Chemical Hazards in Construction

173
Chemical Hazards in Construction The Hazard Communication Standard 1 Chemical Terms and Concepts 18 Hazardous Substances Identification 31 Asbestos in the Construction Industry 51 The Hazards of Asphalt Fumes 94 Lead Hazards in Construction 100 Methylene Chloride Hazards in Construction 120 Methylenedianiline Hazards in Construction 136 Crystalline Silica Hazards in Construction 160

description

Hand bokk who are looking for guidance in chemical hazard in construction

Transcript of Chemical Hazards in Construction

Page 1: Chemical Hazards in Construction

Chemical Hazards in

Construction

The Hazard Communication Standard 1

Chemical Terms and Concepts 18

Hazardous Substances Identification 31

Asbestos in the Construction Industry 51

The Hazards of Asphalt Fumes 94

Lead Hazards in Construction 100

Methylene Chloride Hazards in Construction 120

Methylenedianiline Hazards in Construction 136

Crystalline Silica Hazards in Construction 160

Page 2: Chemical Hazards in Construction

Hazard Communication

1

Page 3: Chemical Hazards in Construction

Introduction

Introduction 1

OSHA’s Hazard Communication Standard (HCS) is based on asimple concept—that employees have both a need and a right toknow the hazards and identities of the chemicals they are exposed towhen working. They also need to know what protective measuresare available to prevent adverse effects from occurring. OSHAdesigned the HCS to provide employees with the information theyneed to know.

Knowledge acquired under the HCS will help employers providesafer workplaces for their employees. When employees have infor-mation about the chemicals being used, they can take steps to reduceexposures, substitute less hazardous materials, and establish properwork practices. These efforts will help prevent the occurrence ofwork-related illnesses and injuries caused by chemicals.

The HCS addresses the issues of evaluating and communicatingchemical hazard information to workers. Evaluation of chemicalhazards involves a number of technical concepts, and is a processthat requires the professional judgment of experienced experts.That’s why the HCS is designed so that employers who simply usechemicals—rather than produce or import them—are not required toevaluate the hazards of those chemicals. Hazard determination is theresponsibility of the manufacturers and importers of the chemicals,who then must provide the hazard information to employers thatpurchase their products

Employers that do not produce or import chemicals need onlyfocus on those parts of the rule that deal with establishing a work-place program and communicating information to their workers.This publication is a general guide for such employers to help themdetermine what the HCS requires. It does not supplant or substitutefor the regulatory provisions, but rather provides a simplified outlineof the steps an average employer would follow to meet thoserequirements.

2

Page 4: Chemical Hazards in Construction

Hazard Communication Guidelines for Compliance

Becoming Familiar with the Rule2

OSHA has provided a simple summary of the HCS in a pamphletentitled Chemical Hazard Communication (OSHA 3084). Someemployers prefer to familiarize themselves with the rule’s require-ments by reading this pamphlet. A single, free copy may be obtainedfrom your local OSHA Area Office, or by contacting the OSHAPublications Office at (202) 693-1888.

The standard itself is long and some parts are technical, but thebasic concepts are simple. In fact, the requirements reflect whatmany employers have been doing for years. You may find that youalready largely comply with many of the provisions and will simplyhave to modify your existing programs somewhat. If you are operat-ing in an OSHA-approved State Plan State, you must comply withthe State’s requirements, which may be different than those of theFederal rule. Many of the State Plan States had hazard communica-tion or “right-to-know” laws prior to promulgation of the federalrule. Employers in State Plan States should contact their StateOSHA Offices for more information regarding applicable require-ments. (See the list of contacts in “States with Approved Plans” atthe back of this booklet.)

The HCS requires information to be prepared and transmittedregarding all hazardous chemicals. The HCS covers both physicalhazards (such as flammability) and health hazards (such as irritation,lung damage, and cancer.) Most chemicals used in the workplacehave some hazard potential, and thus will be covered by the rule.

One difference between this rule and many others adopted byOSHA is that this one is performance-oriented. That means youhave the flexibility to adapt the rule to the needs of your workplace,rather than having to follow specific rigid requirements. It alsomeans that you have to exercise more judgment to implement anappropriate and effective program.

The standard’s design is simple. Chemical manufacturers andimporters must evaluate the hazards of the chemicals they produce orimport. Using that information, they must then prepare labels forcontainers and more detailed technical bulletins called materialsafety data sheets (MSDSs).

Chemical manufacturers, importers, and distributors of hazardouschemicals are all required to provide the appropriate labels andmaterial safety data sheets to the employers to whom they ship the

3

Page 5: Chemical Hazards in Construction

3

Becoming Familiar with the Rule

chemicals. The information must be provided automatically. Everycontainer of hazardous chemicals you receive must be labeled,tagged, or marked with the required information. Your suppliers alsomust send you a properly completed MSDS at the time of the firstshipment of the chemicals, and with the next shipment after theMSDS is updated with new and significant information about thehazards.

You can rely on the information received from your suppliers.You have no independent duty to analyze the chemical or evaluatethe hazards of it.

Employers that “use” hazardous chemicals must have a programto ensure the information is provided to exposed employees. “Use”means to package, handle, react, or transfer. This is an intentionallybroad scope, and includes any situation where a chemical is presentin such a way that employees may be exposed under normal condi-tions of use or in a foreseeable emergency.

The requirements of the rule that deal specifically with the hazardcommunication program are found in the standard in paragraphs (e),written hazard communication programs; (f), labels and other formsof warning; (g), material safety data sheets; and (h), employeeinformation and training. The requirements of these paragraphsshould be the focus of your attention. Concentrate on becomingfamiliar with them, using paragraphs (b), scope and application, and(c), definitions, as references when needed to help explain theprovisions.

There are two types of work operations where coverage of the ruleis limited. These are laboratories and operations where chemicalsare only handled in sealed containers (e.g., a warehouse). Thelimited provisions for these workplaces can be found in paragraph(b), scope and application. Basically, employers having these typesof work operations need only keep labels on containers as they arereceived, maintain material safety data sheets that are received andgive employees access to them, and provide information and trainingfor employees. Employers do not have to have written hazardcommunication programs and lists of chemicals for these types ofoperations.

The limited coverage of laboratories and sealed container opera-tions addresses the obligation of an employer to the workers in the

4

Page 6: Chemical Hazards in Construction

Hazard Communication Guidelines for Compliance

4

operations involved, and does not affect the employer’s duties as adistributor of chemicals. For example, a distributor may havewarehouse operations where employees would be protected under thelimited sealed container provisions. In this situation, requirementsfor obtaining and maintaining MSDSs are limited to providing accessto those received with containers while the substance is in theworkplace, and requesting MSDSs when employees request accessfor those not received with the containers. However, as a distributorof hazardous chemicals, that employer will still have responsibilityfor providing MSDSs to downstream customers at the time of thefirst shipment and when the MSDS is updated. Therefore, althoughthey may not be required for the employees in the work operation,the distributor may, nevertheless, have to have MSDSs to satisfyother requirements of the rule.

5

Page 7: Chemical Hazards in Construction

Identifying Responsible Staff 5

Identifying Responsible Staff

Hazard communication will be a continuing program in yourfacility. Compliance with HCS is not a “one shot deal.” In order tohave a successful program, you must assign responsibility for boththe initial and ongoing activities that have to be undertaken tocomply with the rule. In some cases, these activities may be part ofcurrent job assignments. For example, Site Supervisors are fre-quently responsible for on-the-job training sessions. Early identifica-tion of the responsible employees and their involvement in develop-ing your action plan will result in a more effective program design.Involving affected employees also will enhance the evaluation of theeffectiveness of your program.

For any safety and health program, success depends on commit-ment at every level of the organization. This is particularly true forhazard communication, where success requires a change in behavior.This will occur only if employers understand the program and arecommitted to its success, and if the people presenting the informationmotivate employees.

6

Page 8: Chemical Hazards in Construction

Hazard Communication Guidelines for Compliance

Identifying Hazardous Chemicals in the Workplace6

The standard requires a list of hazardous chemicals in the work-place as part of the written hazard communication program. The listwill eventually serve as an inventory of everything for which youmust maintain an MSDS. At this point, however, preparing the listwill help you complete the rest of the program since it will give yousome idea of the scope of the program required for compliance inyour facility.

The best way to prepare a comprehensive list is to survey theworkplace. Purchasing records also may help, and certainly employ-ers should establish procedures to ensure that in the future purchas-ing procedures result in MSDSs being received before using amaterial in the workplace.

The broadest possible perspective should be taken when doing thesurvey. Sometimes people think of “chemicals” as being only liquidsin containers. The HCS covers chemicals in all physical forms—liquids, solids, gases, vapors, fumes, and mists—whether they are“contained” or not. The hazardous nature of the chemical and thepotential for exposure are the factors that determine whether achemical is covered. If it’s not hazardous, it’s not covered. If thereis no potential for exposure, (e.g., the chemical is inextricably boundand cannot be released), the rule does not cover the chemical.

Look around. Identify the chemicals in containers, includingpipes, but also think about chemicals generated in the work opera-tions. For example, welding fumes, dusts, and exhaust fumes are allsources of chemical exposures. Read labels provided by the suppli-ers on hazard information. Make a list of all chemicals in theworkplace that are potentially hazardous. For your own informationand planning, you also may want to note on the list the location(s) ofthe products within the workplace, and an indication of the hazardsas found on the label. This will help you as you prepare the rest ofyour program.

Paragraph (b), scope and application, includes exemptions forvarious chemicals or workplace situations. After compiling thecomplete list of chemicals, you should review paragraph (b) todetermine if any of the items can be eliminated from the list becausethey are exempted materials. For example, food, drugs, and cosmet-ics brought into the workplace for employee consumption areexempt; rubbing alcohol in the first aid kit would not be covered.

7

Page 9: Chemical Hazards in Construction

7

Identifying Hazardous Chemicals in the Workplace

Once you have compiled as complete a list as possible of thepotentially hazardous chemicals in the workplace, the next step is todetermine if you have received material safety data sheets for all ofthem. Check your files against the inventory you have just compiled.If any are missing, contact your supplier and request one. It is agood idea to document these requests, either by copy of a letter or anote regarding telephone conversations. If you have MSDSs forchemicals that are not on your list, figure out why. Maybe you don’tuse the chemical anymore. Or maybe you missed it in your survey.Some suppliers do provide MSDSs for products that are not hazard-ous. These do not have to be maintained by you. If you havequestions regarding the hazard status of a chemical, contact themanufacturer, distributor, or importer.

You should not allow employees to use any chemicals for whichyou have not received an MSDS. The MSDS provides informationyou need to ensure you have implemented proper protective mea-sures for exposure.

8

Page 10: Chemical Hazards in Construction

Hazard Communication Guidelines for Compliance

8 Preparing and Implementing a Hazard Communication Program

The HCS requires all workplaces where employees are exposed tohazardous chemicals to have a written plan that describes how thatfacility will implement the standard. Preparation of the plan is notjust a paper exercise—all of the elements must be implemented inthe workplace to comply with the rule. See paragraph (e) of thestandard for the specific requirements regarding written hazardcommunication programs. The only work operations that do nothave to comply with the written plan requirements are laboratoriesand work operations where employees only handle chemicals insealed containers. See paragraph (b), scope and application, for thespecific requirements for these two types of workplaces.

The plan does not have to be lengthy or complicated. It is in-tended to be a blueprint for implementing your program—an assur-ance that all aspects of the requirements have been addressed.

Many trade associations and other professional groups haveprovided sample programs and other assistance materials to affectemployers. These have been very helpful to many employers sincethey tend to be tailored to the particular industry involved. You maywish to investigate whether your industry trade groups have devel-oped such materials.

Although such general guidance may be helpful, you must remem-ber that the written program has to reflect what you are doing in yourworkplace. Therefore, if you use a generic program, you must adaptit to address the facility it covers.

For example, the written plan must list the chemicals present atthe site and indicate where written materials will be made availableto employees. It also may indicate who is responsible for the variousaspects of the program in your facility.

If OSHA inspects your workplace for compliance with the HCS,the OSHA compliance officer will ask to see your written plan at theoutset of the inspection. In general, the following items will beconsidered in evaluating your program.

The written program must describe how the requirements for labelsand other forms of warning, materials safety data sheets, and em-ployee information and training, are going to be met in your facility.The following discussion provides the type of information compli-ance officers will be looking for to decide whether you have properlyaddressed these elements of the hazard communication program.

9

Page 11: Chemical Hazards in Construction

9

Preparing and Implementing a Hazard Communication Program

Labels and Other Forms of WarningIn-plant containers of hazardous chemicals must be labeled,

tagged, or marked with the identity of the material and appropriatehazard warnings. Chemical manufacturers, importers, and distribu-tors must ensure that every container of hazardous chemicals theyship is appropriately labeled with such information and with thename and address of the producer or other responsible party. Em-ployers purchasing chemicals can rely on the labels provided by theirsuppliers. If the material is subsequently transferred by the employerfrom a labeled container to another container, the employer will haveto label that container, unless it is subject to the portable containerexemption. See paragraph (f) for specific labeling requirements.

The primary information to be obtained from an OSHA-requiredlabel is the identity for the material and appropriate hazard warnings.The identity is any term which appears on the label, the MSDS, andthe list of chemicals, and thus links these three sources of informa-tion. The identity used by the supplier may be a common or tradename (“Black Magic Formula”), or a chemical name (1, 1, 1 -trichloroethane). The hazard warning is a brief statement of thehazardous effects of the chemical (“flammable,” “causes lungdamage”). Labels frequently contain other information, such asprecautionary measures (“do not use near open flame”) but thisinformation is provided voluntarily and is not required by the rule.Labels must be legible and prominently displayed. There are nospecific requirements for size or color or any specified test.

With these requirements in mind, the compliance officer will belooking for the following types of information to ensure that labelingis properly implemented in your facility:

• Designation of person(s) responsible for ensuring labeling ofin-plant containers;

• Designation of person(s) responsible for ensuring labeling ofany shipped container;

• Description of labeling system(s) used;• Description of written alternatives to labeling of in-plant

containers (if used); and,• Procedures to review and update label information when

necessary.

10

Page 12: Chemical Hazards in Construction

Hazard Communication Guidelines for Compliance

10

Employers that are purchasing and using hazardous chemicals—rather than producing or distributing them—will primarily be con-cerned with ensuring that every purchased container is labeled. Ifmaterials are transferred into other containers, the employer mustensure that these are labeled as well, unless they fall under theportable container exemption (paragraph f(7)). In terms of labelingsystems, you can choose to use the labels provided by your supplierson the containers. These will generally be verbal text labels, and donot usually include numerical rating systems or symbols that requirespecial training. The most important thing to remember is that this isa continuing duty—all in-plant containers of hazardous chemicalsmust always be labeled. Therefore, it is important to designatesomeone to be responsible for ensuring that the labels are maintainedas required on the containers in your facility and that newly pur-chased materials are checked for labels prior to use.

Material Safety Data SheetsChemical manufacturers and importers are required to obtain or

develop a material safety data sheet for each hazardous chemical theyproduce or import. Distributors are responsible for ensuring thattheir customers are provided a copy of these MSDSs. Employersmust have an MSDS for each hazardous chemical which they use.Employers may rely on the information received from their suppliers.The specific requirements for material safety data sheets are inparagraph (g) of the standard.

There is no specific format for the MSDS under the rule, althoughthere are specific information requirements. OSHA has developed anonmandatory format, OSHA Form 174, which may be used bychemical manufacturers and importers to comply with the rule. TheMSDS must be in English. You are entitled to receive from yoursupplier a data sheet which includes all of the information requiredunder the rule. If you do not receive one automatically, you shouldrequest one. If you receive one that is obviously inadequate, with,for example, blank spaces that are not completed, you should requestan appropriately completed one. If your request for a data sheet orfor a corrected data sheet does not produce the information needed,you should contact your local OSHA Area Office for assistance inobtaining the MSDS.

11

Page 13: Chemical Hazards in Construction

11

Preparing and Implementing a Hazard Communication Program

Under the rule, the role of MSDSs is to provide detailed informa-tion on each hazardous chemical, including its potential hazardouseffects, its physical and chemical characteristics, and recommenda-tions for appropriate protective measures. This information shouldbe useful to you as the employer responsible for designing protectiveprograms, as well as to the workers. If you are not familiar withmaterial safety data sheets and with chemical terminology, you mayneed to learn to use them yourself. A glossary of MSDS terms maybe helpful in this regard. Generally speaking, most employers usinghazardous chemicals will primarily be concerned with MSDSinformation regarding hazardous effects and recommended protectivemeasures. Focus on the sections of the MSDS that are applicable toyour situation.

MSDSs must be readily accessible to employees when they are intheir work areas during their workshifts. This may be accomplishedin many different ways. You must decide what is appropriate foryour particular workplace. Some employers keep the MSDSs in abinder in a central location (e.g., in the pickup truck on a construc-tion site.) Others, particularly in workplaces with large numbers ofchemicals, computerize the information and provide access throughterminals. As long as employees can get the information when theyneed it, any approach may be used. The employees must have accessto the MSDSs themselves—simply having a system where theinformation can be read to them over the phone is permitted onlyunder the mobile worksite provision, paragraph (g)(9), when employ-ees must travel between workplaces during the shift. In this situa-tion, they have access to the MSDSs prior to leaving the primaryworksite, and when they return, so the telephone system is simply anemergency arrangement.

In order to ensure that you have a current MSDS for each chemi-cal in the plant as required, and that you provide employee access,the compliance officers will be looking for the following types ofinformation in your written program:

• Designation of person(s) responsible for obtaining and main-taining the MSDSs;

• How such sheets are to be maintained in the workplace (e.g., innotebooks in the work area(s) or in a computer with terminalaccess), and how employees can obtain access to them whenthey are in their work area during the workshift;

12

Page 14: Chemical Hazards in Construction

Hazard Communication Guidelines for Compliance

12

• Procedures to follow when the MSDS is not received at thetime of the first shipment;

• For producers, procedures to update the MSDS when new andsignificant health information is found; and,

• Description of alternatives to actual data sheets in the work-place, if used.

For employers using hazardous chemicals, the most importantaspect of the written program in terms of MSDSs is to ensure thatsomeone is responsible for obtaining and maintaining the MSDSs forevery hazardous chemical in the workplace. The list of hazardouschemicals required to be maintained as part of the written programwill serve as an inventory. As new chemicals are purchased, the listshould be updated. Many companies have found it convenient toinclude on their purchase order the name and address of the persondesignated in their company to receive MSDSs.

Employee Information and TrainingEach employee who may be “exposed” to hazardous chemicals

when working must be provided information and be trained prior toinitial assignment to work with a hazardous chemical, and wheneverthe hazard changes. “Exposure” or “exposed” under the rule meansthat an employee is subjected to a hazardous chemical in the courseof employment through any route of entry (inhalation, ingestion, skincontact, or absorption) and includes potential (e.g., accidental orpossible) exposure. See paragraph (h) of the standard for specificrequirements. Information and training may be done either byindividual chemical, or by categories of hazards (such as flammabil-ity or carcinogenicity). If there are only a few chemicals in theworkplace, then you may want to discuss each one individually.Where there are a large number of chemicals, or the chemicalschange frequently, you will probably want to train generally based onthe hazard categories (e.g., flammable liquids, corrosive materials,carcinogens). Employees will have access to the substance-specificinformation on the labels and MSDSs. Employers must ensure,however, that employees are made aware of which hazard category achemical falls within.

Information and training are a critical part of the hazard communi-cation program. Workers obtain information regarding hazards and

13

Page 15: Chemical Hazards in Construction

13

protective measures through written labels and material safety datasheets. It is through effective information and training, however, thatworkers will learn to read and understand such information, deter-mine how to acquire and use it in their own workplace, and under-stand the risks of exposure to the chemical in their workplaces aswell as the ways to protect themselves. A properly conductedtraining program will ensure comprehension and understanding. It isnot sufficient to either just read material to the workers or simplyhand them material to read. You want to create a climate whereworkers feel free to ask questions. This will help you to ensure thatthe information is understood. You must always remember that theunderlying purpose of the HCS is to reduce the incidence of chemi-cal source illnesses and injuries. This will be accomplished bymodifying behavior through the provision of hazard information andinformation about protective measures. If your program works, youand your workers will better understand the chemical hazards withinthe workplace. The procedures you establish, regarding, for ex-ample, purchasing, storage, and handling of these chemicals willimprove, and thereby reduce the risks posed to employees exposed tothe chemical hazards involved. Furthermore, your workers’ compre-hension also will be increased, and proper work practices will befollowed in your workplace.

If you are going to do the training yourself, you will have tounderstand the material and be prepared to motivate the workers tolearn. This is not always an easy task, but the benefits are worth theeffort. More information regarding appropriate training can be foundin Training Requirements in OSHA Standards and Training Guide-lines (OSHA 2254), which contains voluntary training guidelinesprepared by OSHA’s Training Institute. A copy of this document isavailable from the Superintendent of Documents, GovernmentPrinting Office, P.O. Box 371954, Pittsburgh, PA 15250-7954; (202)512-1800.

When reviewing your written program regarding information andtraining, consider the following items:

• Designation of person(s) responsible for conducting training;• Format of the program used (audiovisuals, class room

instruction);• Elements of the training programs (should be consistent with

the elements in paragraph (h) of the HCS); and,

Preparing and Implementing a Hazard Communication Program14

Page 16: Chemical Hazards in Construction

Hazard Communication Guidelines for Compliance

14

• Procedure to train new employees at the time of their initialassignment to work with a hazardous chemical, and to trainemployees when introducing a new hazard into the workplace.

The written program should provide enough details about theemployer’s plans in this area to assess whether or not a good faitheffort is being made to train employees. OSHA does not expect thatevery workers will be able to recite all the information about eachchemical in the workplace. In general, the most important aspects oftraining under the HCS are to ensure that employees are aware thatthey are exposed to hazardous chemicals, that they know how to readand use labels and material safety data sheets, and that, as a conse-quence of learning this information, they are following the appropri-ate protective measures established by the employer. OSHA compli-ance officers will be talking to employees to determine if they havereceived training, if they know they are exposed to hazardous chemi-cals, and if they know where to obtain substance specific informationon labels and MSDSs.

The rule does not require employers to maintain records ofemployee training, but many employers choose to do so. This mayhelp you monitor your own program to ensure that you have trainedall employees appropriately. If you already have a training program,you may simply have to supplement it with whatever additionalinformation is required under the HCS. For example, constructionemployers that are already in compliance with the constructiontraining standard (29 CFR 1926.21 ) will have little extra training todo.

An employer can provide employees information and trainingthrough whatever means found appropriate and protective. Althoughthere would always have to be some training on site (such as inform-ing employees of the location and availability of the written programand MSDSs), employee training may be satisfied in part by generaltraining about the requirements of the HCS which is provided by, forexample, trade associations, unions, colleges, and professionalschools. In addition, previous training, education, and experience ofa worker may relieve the employer of some of the burdens of infor-mation and training that worker. Regardless of the method reliedupon, however, the employer is always ultimately responsible forensuring that employees are adequately trained. If the compliance

15

Page 17: Chemical Hazards in Construction

15

officer finds that the training is deficient, the employer will be citedfor the deficiency regardless of who actually provided the training onbehalf of the employer.

In addition to these specific items, compliance officers also will beasking the following questions in assessing the adequacy of theprogram:

• Does a list of the hazardous chemicals exist in each work areaor at a central location?

• Are methods the employer will use to inform employees of thehazards of non-routine tasks outlined?

• Are employees informed of the hazards associated with chemi-cals contained in unlabeled pipes in their work areas?

• On multi-employer worksites, has the employer provided otheremployers with information about labeling systems and precau-tionary measures where the other employers have employeesexposed to the initial employer’s chemicals?

• Is the written program made available to employees and theirdesignated representatives?

If your program adequately addresses the means of communicat-ing information to employees in your workplace and providesanswers to the basic questions outlined above, it will comply with therule.

Preparing and Implementing a Hazard Communication Program16

Page 18: Chemical Hazards in Construction

Hazard Communication Guidelines for Compliance

16 Checklist for Compliance

The following checklist will help to ensure you comply with therule:

• Obtained a copy of the rule.• Read and understood the requirements.• Assigned responsibility for tasks.• Prepared an inventory of chemicals.• Ensured containers are labeled.• Obtained MSDS for each chemical.• Prepared written program.• Made MSDSs available to workers.• Conducted training of workers.• Established procedures to maintain current program.• Established procedures to evaluate effectiveness.

17

Page 19: Chemical Hazards in Construction

Chemical Terms and Concepts

18

Page 20: Chemical Hazards in Construction

BASIC CHEMISTRY and TOXICOLOGICAL TERMS & CONCEPTS A. Introduction

1. There are 5 to 6 million known chemicals, with this number growing at the rate of 6,000 more each month.

2. 64,000 of these chemicals are known to be hazardous, with 1000 more hazardous chemicals proposed for manufacture each year.

3. Most hazardous chemicals are not regulated.

a. DOT regulates 2,700 chemicals

b. OSHA regulates 400 chemicals

4. Less than 2% of the 64,000 known hazardous chemicals have been studied thoroughly enough to fully understand their health hazards

a. Examples:

(1) There are 3,350 pesticides on the market with information available to make a partial health assessment on about 34% of them.

(2) There are 1,815 drugs on the market with information available to make a partial health assessment on about 36% of them

(3) There are 8,627 food additives on the market with information available to make a partial health assessment on about 19% of them

(4) There are 48,500 other commonly used industrial chemicals on the market with information available to make a partial health assessment on about 10% of them

B. Terminology - for the purposes of this course and for most general usage, the term

hazardous materials or HAZMATS is sufficient to describe chemicals that may be hazardous to people or the environment. But many government regulations attach particular meaning to various terms often thought to synonymous.

19

Page 21: Chemical Hazards in Construction

1. The term "hazardous materials" is used to describe DOT regulated materials that are considered to be a threat in transport.

2. The term "hazardous substances":

a. Is used to describe EPA regulated materials which may threaten the environment

b. OSHA uses this term to describe every chemical regulated by DOT and EPA

3. The term "extremely hazardous substances" is used to describe EPA regulated substances for materials requiring reporting of spills if the spill exceeds the published Reportable Quantity (RQ)

4. The term "toxic chemicals" is used to describe EPA regulated substances whose emissions or releases must be reported annually by manufacturers.

5. The term "hazardous wastes" is used to describe EPA regulated wastes under RCRA.

6. The term "hazardous chemicals" is used by OSHA to denote any chemical that would be a risk to employees in the workplace.

C. Physical State

1. The Physical State of a chemical is important since a change in physical state may equal an increase in hazard.

a. A solid has definite size & shape (1) It usually has a melting point at which it becomes a liquid

(2) Solids that undergo sublimation turn directly from a solid to a gaseous state

b. A liquid can flow easily, it has no shape but it has volume. (1) It usually has a freezing point at which it becomes a solid

(2) It usually has a boiling point at which it becomes a gas or vapor.

c. A gas has no independent shape or volume.

2

20

Page 22: Chemical Hazards in Construction

(1) It usually may be condensed into a liquid.

d. Many HAZMATS are often in flux.

(1) Gasoline constantly changing from a liquid to a vapor.

(2) Dry ice constantly changing from a solid to a gas.

(3) Ice melting from a solid to a liquid. D. Organic Chemicals

1. Organics vs inorganic compounds a. Organics contain carbon, inorganics do not

b. Common organics include hydrocarbons and many other naturally forming chemicals

2. A very common and basic family of organic chemicals are hydrocarbons.

a. Hydrocarbons are molecules made of atoms of hydrogen and carbon.

b. Hydrocarbons include oil and oil related products such as:

(1) Natural Gas, Propane, kerosene, gasoline, fuel oil etc.

3. Hydrocarbon Derivatives are formed by replacing hydrogen or carbon atoms with another element or molecule; the new element or molecule determines the properties of the new molecule

a. Halogenated hydrocarbons are formed when one or more halogens (fluorine, chlorine, bromine, iodine) are added to a hydrocarbon chain

(1) When possible one should try to avoid halogenated hydrocarbons since they can cause damage to the central nervous system. They are also an environmental hazard since they attack the ozone layer, decompose and emit toxic vapors in fires, and their vapors are heavier than air.

b. Alcohols are formed when the hydroxyl group (oxygen and hydrogen) is added to a hydrocarbon chain.

21

Page 23: Chemical Hazards in Construction

(1) Examples: methyl, ethyl, isopropyl alcohol. (2) The hydroxyl group makes the molecule more water soluble.

(3) The hydroxyl group causes an affinity for oxygen so the alcohol will burn very hot.

(4) Most alcohols are toxic by ingestion or inhalation.

(a) methyl alcohol causes blindness. (b) ethyl alcohol can affect the central nervous system.

c. Ethers are formed when an oxygen atom is placed between two hydrocarbon groups.

(1) Ethers are often highly volatile and burn intensely. (2) Ethers often have low boiling points and flash points.

(3) Ethers tend to react with oxygen to form unstable peroxides.

d. Amines are formed when a nitrogen - hydrogen group is added to a hydrocarbon chain.

(1) Amines are often very toxic and corrosive.

(2) Amines commonly cause respiratory, liver, or kidney damage; and are often carcinogenic

e. Nitros are formed when a nitrogen oxygen group is added to a hydrocarbon

(1) Nitros are often explosive and toxic E. Explosives

1. An explosion can be defined as a "rapid oxidation in a confined space". An "oxidation" of this type is an "oxidation reduction reaction with the evolution of heat and light" which is the definition of fire.

a. In other words, an explosion is a confined fire.

2. The Department of Transportation (DOT) classifies explosives in six categories.

22

Page 24: Chemical Hazards in Construction

(1) Division 1.1 explosives are the most hazardous and represent explosives that could present a massive projectile hazard and/or may be easily detonated.

(2) Division 1.2 explosives represent those explosives with some limited projectile hazard and may include propellants and some pyrotechnics.

(3) Division 1.3 explosives that primarily present a fire hazard.

(4) Division 1.4 explosives that present no significant blast hazard.

(5) Division 1.5 insensitive explosives such as blasting agents that are used to initiate larger explosions in Division 1.1 and 1.2 explosives.

(6) Division 1.6 extremely insensitive detonating substances.

F. Corrosives

1. Corrosives include acids and caustics. Caustics are also referred to as bases or alkalis.

2. ph is a method of expressing the intensity of an acid or base which is determined by measuring the hydrogen-ion concentration.

a. ph is measured on a logarithmic scale which ranges from 1 to 14.

b. A ph < 7 indicates an Acid, while a PH > 7 indicates a base (alkali or caustic). A ph of 7 is neutral.

c. The lower the ph the more acidic a material is.

d. The higher the ph the more caustic a material is.

2. Both acids and caustics are corrosive since they will both damage skin and deteriorate metal.

a. The Department of Transportation (DOT) classifies corrosives by whether or not they will damage skin and deteriorate metal.

b. The Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA) both classify corrosives as either acids or bases in accordance with their ph.

23

Page 25: Chemical Hazards in Construction

3. Although acids and caustics are both classified as corrosives they are actually very different. Acids and caustics are incompatible and may react violently with each other (a neutralization reaction).

4. Inorganic acids (those with no carbon) are usually strong acids.

5. Organic acids (those containing carbon) are usually weak acids, so try to use organic acids.

G. Hazardous Liquids - It is important to note that liquids do not burn. Only the vapors they produce may burn. Therefore a flammable liquid that is not readily producing vapors (like kerosene) is much safer than a flammable liquid that is constantly producing vapors (like gasoline).

1. Flammable liquids

a. Flammable liquids are defined by DOT as liquids having a flashpoint less than or equal to 141º F and combustible liquids are defined as any liquid that does not meet the definition of any other hazard class specified in this subchapter and has a flash point above 60.5°C (141°F) and below 93 °C (200 °F). (DOT has other elements to these definitions also)

b. OSHA defines Flammable and Combustible liquids as follows:

Flammable liquid is any liquid having a flashpoint below 100 deg. F. except any mixture having components with flashpoints of 100 deg. F. or higher, the total of which make up 99 percent or more of the total volume of the mixture. Flammable liquids shall be known as Class I liquids. Class I liquids are divided into three classes as follows:

Class IA includes liquids having flashpoints below 73 deg. F. and having a boiling point below 100 deg. F.

Class IB includes liquids having flashpoints below 73 deg. F. and having a boiling point at or above 100 deg.

Class IC includes liquids having flashpoints at or above 73 deg. F. and

below 100 deg. F.

Combustible liquid is any liquid having a flashpoint at or above 100 deg. F.

Combustible liquids shall be divided into two classes as follows: Class II Liquids Class III Liquids

24

Page 26: Chemical Hazards in Construction

Class II liquids include those with flashpoints at or above 100 deg. F. and below

140 deg. F., except any mixture having components with flashpoints of 200 deg. F.or higher, the volume of which make up 99 percent or more of the total volume of the mixture.

Class III liquids include those with flashpoints at or above 140 deg. F. Class III liquids are subdivided into two subclasses:

Class IIIA liquids Class IIIB liquids

Class IIIA liquids include those with flashpoints at or above 140 deg. F.

and below 200 deg. F., except any mixture having components with flashpoints of 200 deg., or higher, the total volume of which make up 99 percent or more of the total volume of the mixture.

Class IIIB liquids include those with flashpoints at or above 200 deg. F.

2. Toxic liquids are those that are toxic by skin absorption, ingestion, or injection. Only their vapors could be toxic by inhalation. Therefore if the liquid is not readily producing vapors it is more safe than if it were producing vapors.

3. Vapor Pressure is the pressure exerted by vapor from a liquid at equilibrium.

a. Vapor pressure is a measure of the ability of a material to evaporate into a gas or vapor. The higher the vapor pressure of a substance the faster it will turn into a vapor or gas.

b. Volatile liquids are liquids are liquids that have a high vapor pressure at room temperature.

4. Boiling Point is the temperature at which liquid changes to a gas or vapor

a. A higher molecular weight usually means a higher boiling point.

b. A lower boiling point is more dangerous since the material will more readily produce vapors.

5. Flash Point is the lowest temperature at which a material gives off enough vapor to form an ignitable mixture with air.

a. The lower the flash point of a substance the more flammable it is.

25

Page 27: Chemical Hazards in Construction

6. Solubility is the extent to which a substance will dissolve in another (usually water).

7. Specific Gravity is a comparison of the density of a liquid as compared to water which. Water has a specific gravity of 1.

a. A material with a specific gravity < 1 means that it is lighter than water so it will float on water.

b. A material with a specific gravity > 1 means that it is heavier than water so it sinks in water.

H. Hazardous Gases

1. Hazardous Gases include: a. Flammable gases. b. Non-flammable gases.

(1) Even non-flammable, non-toxic gases are hazardous because they are stored and transported under pressure (compressed).

(2) If the vessel in which the gas is contained is heated the gas will expand with the potential of rupturing the container.

c. Poisonous (or toxic) gases. d. Some have multiple hazards.

(1) Some gases may be both flammable and toxic.

2. Vapor Density for gas/vapors is a comparison of the mass/unit volume of the gas/vapor to air. Air has a vapor density of 1.

a. A vapor density < 1 means the material is lighter than air so it will rise in air

b. A vapor density > 1 means the material is heavier than air so it will sink in air

(1) If a material is heavier than air and toxic or flammable it may endanger a very large area

26

Page 28: Chemical Hazards in Construction

(2) If a material is heavier than air and non-toxic or non-flammable it may still displace air and suffocate its victims.

c. Propane has a vapor density of 1.56, while methane has a vapor density of .55

d. Some common materials that are lighter than air are ammonia, hydrogen, acetylene, and natural gas

3. Flammable or Explosive Limits represents the range in which a gas or vapor is mixed with air in a proportion that is flammable.

a. The UEL (Upper Explosive Limit) is the concentration above which the mixture is too "rich" to burn (too much fuel or too little air).

b. The LEL (Lower Explosive Limit) is the concentration below which the mixture is too "lean" to burn (not enough fuel or too much air).

I. Flammable Solids

1. Flammable Solids are solids that readily ignite and burn vigorously.

a. The ignition may be by friction, moisture absorption, or chemical reaction.

2. Melting Point is the temperature at which a solid changes to liquid.

a. Inorganic materials usually have higher melting points than organic.

J. Oxidizers and Organic Peroxides

1. Oxidizers are chemicals that can take the place of oxygen in a fire. For example many materials will burn in a chlorine atmosphere with no oxygen present.

a. Oxidizers may increase fire intensity.

b. Oxidizers may increase sensitivity to heat, shock & friction.

c. Oxidizers may react spontaneously with organic matter.

2. Peroxides react easily to give up their oxygen.

27

Page 29: Chemical Hazards in Construction

a. Peroxides act similarly to oxidizers except instead of replacing oxygen in a reaction they release oxygen contained within their own molecular structure.

a. Oxidizers may increase fire intensity.

b. Oxidizers may increase sensitivity to heat, shock & friction.

c. Oxidizers may react spontaneously with organic matter.

K. Etiologic Agents

1. Etiologic agents cause infectious disease in humans.

a. Examples include hepatitis B and HIV. L. Reactivity

1. Reactivity is the tendency of a material to react with other substances.

a. Some substances tend to easily react with many other substances.

b. An example would be the spontaneous reaction between chlorine and most hydrocarbons.

M. Polymerization

1. Polymerization is the combining of single chemical units (monomers) into chains (polymers).

a. A catalyst is a chemical that is used to speed a reaction but is not itself a part of the reaction. Catalysts can be used to control the speed of polymerization.

b. An inhibitor is sometimes added to prevent polymerization. N. Toxicology

1. Toxicology is the study of chemical or physical agents that produce adverse health effects.

28

Page 30: Chemical Hazards in Construction

2. Toxicity is the extent of the adverse health effects of chemical or physical agents.

3. Exposure - 29 CFR 1910.1200 defines exposure as "any employee subjected to a hazardous chemical in the course of employment through any route of entry".

a. Exposure is dependent upon: (1) Duration of exposure. (2) Concentration of substance.

4. Toxic chemicals may enter our bodies in four different ways. These routes of entry are:

a. absorption through skin

b. inhalation through lungs

c. ingestion through mouth

d. Injection

5. Toxic chemicals effect the internal organs of the human body in many different ways.

a. Etiologic agents cause infectious diseases. b. Hepotoxins produce liver damage.

c. Nephrotoxins produce kidney damage.

d. Neurotoxins produce damage to the nervous system.

e. Pulmonary Toxins irritate or damage the lung tissue.

f. Mutagens effect reproductive capability usually by genetic or chromosome damage.

g. Teratogens affect the development of existing fetuses.

h. Carcinogens cause cancer.

29

Page 31: Chemical Hazards in Construction

6. Acute Effects from hazardous chemicals are immediate short term effects. They are generally the biological effects of a single short term exposure.

7. Chronic Effects from hazardous chemicals are long term effects of repeated exposure.

8. IDLH stands for Immediately Dangerous to Life & Health. a. It usually expressed as a "concentration", often a percentage.

b. IDLH is the maximum concentration of a material from which one could escape within 30 minutes without experiencing irreversible health effects

9. LD50 stands for Lethal Dose 50 which is the dosage by ingestion at which 50% of the lab animals died.

10. LC50 stands for Lethal Concentration 50 which is the dosage by inhalation at which 50% of the lab animals died.

11. TLV stands for Threshold Limit Value which is the airborne concentration of a material that nearly all persons can be exposed day after day without adverse effects.

12. TWA stands for Time Weighted Average which is the TLV related to a normal 8 hour work day.

13. STEL stands for Short Term Exposure Limit which is based on a specific time period, often 15 minute exposure, for a maximum of 4 times/day, with a minimum of 1 hour between exposures, provided the TLV and TWA are not exceeded.

14. PEL stands for Permissible Exposure Limits. This is an OSHA term and represents the maximum allowable exposure for a specific time period.

30

Page 32: Chemical Hazards in Construction

Hazardous Substances

Identification

31

Page 33: Chemical Hazards in Construction

HAZARDOUS SUBSTANCES IDENTIFICATION I. INTRODUCTION At an incident, response personnel may be exposed to a number of substances that are hazardous because of their biological, radiological or chemical characteristics. Biological agents are living organisms (or their products) that can cause sickness or death to exposed individuals. Radiological materials are considered hazardous because of their ability to emit various types of radiation at intensities that may be harmful if response personnel are either inadequately shielded from the radiation source or exposed to the radiation for too long a time. Chemical hazards are classified into several groups, including fire, toxic, corrosive, and reactive hazards. A material may elicit more than one chemical hazard during an incident. For example, toxic vapors can be released during chemical fires. The hazards can be a result of the physical/chemical properties of a material or of its chemical reactivity with other materials or the environment to which it is exposed. Many hazards may be present at any one incident. It is important to understand the fundamentals of each and their relationships so that effective safety practices may be employed to reduce the risk to the public and response personnel. II. BIOLOGICAL HAZARDS There are five general categories of biological agents that are capable of causing infection or disease in exposed individuals. They are: viral, rickettsial/chlamydial, bacterial, fungal, and parasitic. These agent types may be present at hazardous waste sites and hazardous material spills. Like chemical hazards, they may be dispersed throughout the environment via wind and water. Many biological agents have complex life cycles that require host and intermediate (carrier) host organisms to complete their growth cycles. Rodents, for example, which are commonly found at landfills, act as carriers for the rabies virus. Likewise, the Rocky Mountain Spotted Fever tick can carry the bacillus that produces this disease in many.

32

Page 34: Chemical Hazards in Construction

The same personnel protective requirements that are used against a hazard can be applied to biological hazards. Body coverings and respiratory protective equipment should be utilized. Personal cleanliness is especially important. Showering after removing protective clothing and thoroughly washing exposed body parts, including hands and face, should help remove any residual contamination. III. RADIATION HAZARDS

Radioactive materials that may be encountered at a site can emit three types of harmful radiation: alpha particles, beta particles and gamma waves. All three forms harm living organisms by imparting energy which ionizes molecules in the cells. Hence, the three are referred to as ionizing radiation. Ionization may upset the normal cellular function causing cell dysfunction or death.

An alpha particle is positively charged. The beta is an electron possessing a negative charge. Both particles have mass and energy. Both are emitted from the nucleus. They travel short distances in material before interaction with the material causes them to lose their energy. The outer layers of the skin and clothing generally protect against these particles. Therefore, they are considered hazardous primarily when they enter the body through inhalation or ingestion.

Gamma radiation is pure electromagnetic energy and is wave-like rather than particulate. Gamma waves pass through all materials to some degree. Clothing, including protective gear, will not prevent gamma radiation from interacting with body tissue.

Unlike many hazardous substances that possess certain properties which can alert response personnel to over-exposure (odor, irritation or taste), radiation has no such warning properties. Hence, preventing the radioactive material from entering the body or protecting against external radiation is the best protection. As with biological and chemical hazards, the use of respiratory and personnel protective equipment, coupled with scrupulous personal hygiene, will afford good protection against radioactive particles.

IV. CHEMICAL HAZARDS A. Fire Hazards

33

Page 35: Chemical Hazards in Construction

Fire Protection The Fire Tetrahedron Four things must be present at the same time in order to produce fire:

1. Enough oxygen to sustain combustion,

2. Enough heat to raise the material to its ignition temperature,

3. Some sort of fuel or combustible material, and

4. The chemical, exothermic reaction that is fire. Oxygen, heat, and fuel are frequently referred to as the "fire triangle." Add in the fourth element, the chemical reaction, and you actually have a fire "tetrahedron." The important thing to remember is: take any of these four things away, and you will not have a fire or the fire will be extinguished. The concentration of the fuel and the oxygen must be high enough to allow ignition and maintain the burning process. Combustion is a chemical reaction that requires heat to proceed: fuel + oxygen ----------------------> byproducts Heat is either supplied by the ignition source and is maintained by the combustion, or supplied from and external source. Most fires can be extinguished by removing one of these components. For example, water applied to a fire by itself generates enough heat to self-ignite and combust, spontaneous combustion occurs, either as a fire or explosion.

A fire can be defined as a self-sustaining oxidation-reduction reaction with the evolution of heat and light. Each side of the fire tetrahedron represents one of the necessary elements of a fire. A fire requires sufficient heat, fuel in an ignitable form, oxygen in a

34

Page 36: Chemical Hazards in Construction

proper mixture with the fuel, and a chemical chain reaction involving these elements. Removing any one of these elements will extinguish the fire.

Flammability Flammability is the ability of a material to generate a sufficient concentration of combustible vapors under normal conditions to be ignited and produce a flame.

It is necessary to have a proper fuel-to-air ratio (expressed as the percentage of fuel in air) to allow combustion. There is a range of fuel concentrations in air for each material that is optimal for the ignition and the sustenance of combustion. There is a range of fuel concentrations in air for each material that is optimal for the ignition and the sustenance of combustion. This is called the Flammable Range.

UEL

LELFlammable or Flammable or

Explosive RangeExplosive Range

The lowest concentration of fuel in this range is the Lower Flammable Limit (LFL). Concentrations less than the LFL are not flammable because there is too little fuel, that is, the mixture is too "lean". The highest ratio that is flammable is the Upper Flammable Limit (UFL). Concentrations greater than the UFL are not flammable because there is too much fuel displacing the oxygen (resulting in too little oxygen). This mixture is too "rich". Fuel concentrations between the LFL and UFL are optimal for starting and sustaining fire. Example: The LFL for benzene is 1.3% (13,000 ppm), the UFL is 7.1% (71,000 ppm), thus the flammable range is 1.3% to 7.1%. Flash Point

35

Page 37: Chemical Hazards in Construction

The U.S. Department of Transportation (DOT), the Occupational Safety and Health Administration (OSHA), the National Institute for Occupational Safety and Health (NIOSH), and the National Fire Protection Association (NFPA) have established strict definitions for flammability based on the flash point of a material. The flash point is the lowest temperature at which a material will produce sufficient flammable vapors to ignite when an ignition source is present. Flammable and Combustible Liquids A Combustible liquid is any liquid having a flashpoint at or above 100 deg. F. Combustible liquids are divided into two classes: Class II Liquids and Class III Liquids.

Class II liquids include those with flashpoints at or above 100 deg. F. and below 140 deg. F., except any mixture having components with flashpoints of 200 deg. F. or higher, the volume of which make up 99 percent or more of the total volume of the mixture.

Class III liquids include those with flashpoints at or above 140 deg. F. Class III liquids are subdivided into two subclasses: Class IIIA liquids and Class IIIB liquids.

Class IIIA liquids include those with flashpoints at or above 140 deg. F. and below 200 deg. F., except any mixture having components with flashpoints of 200 deg., or higher, the total volume of which make up 99 percent or more of the total volume of the mixture.

Class IIIB liquids include those with flashpoints at or above 200 deg. F.

A Flammable liquid is any liquid having a flashpoint below 100 deg. F. except any mixture having components with flashpoints of 100 deg. F. or higher, the total of which make up 99 percent or more of the total volume of the mixture. Flammable liquids shall be known as Class I liquids. Class I liquids are divided into three classes as follows:

Class IA includes liquids having flashpoints below 73 deg. F. and having a boiling point below 100 deg. F.

Class IB includes liquids having flashpoints below 73 deg. F. and having a boiling point at or above 100 deg.

Class IC includes liquids having flashpoints at or above 73 deg. F. and below 100 deg. F.

36

Page 38: Chemical Hazards in Construction

B. Explosive Hazard 1. Explosives An explosive is a substance which undergoes a very rapid chemical

transformation producing large amounts of gases and heat. Due to the heat produced, any gases produced, for example, nitrogen, oxygen, carbon monoxide, carbon dioxide, and steam, due to the heat produced, rapidly expand at velocities exceeding the speed of sound. This creates both a shockwave (high pressure wave front) and noise (brisance).

2. Types of Explosive Hazards High or detonating: Chemical transformation occurs very rapidly with

detonation rates as high as 4 miles per second. The rapidly expanding gas produces a shock wave which may be followed by combustion.

- Primary high explosive: detonating wave produced in an extremely shore period of time. May be detonated by shock, heat, or friction. Examples are lead azide, mercury fulminate, and lead styphnate.

- Secondary high explosive: generally needs a booster to cause them to detonate. Relatively insensitive to shock, heat, or friction. Examples are tetryl, cyclonite, dynamite, and TNT.

Low or deflagrating: Rate of deflagration up to 1000 feet per second. Generally combustion is followed by a shock wave. Examples are smokeless powder, magnesium, and molotov cocktail.

3. Practical Considerations High or low does not indicate the explosion hazard (or power) but only the

rate of chemical transformation. Explosions can occur as a result of reactions between many chemicals not

ordinarily considered as explosives. Ammonium nitrate, a fertilizer, can

37

Page 39: Chemical Hazards in Construction

explode under the right conditions. Alkali metals and water explode; as will water and peroxide salts. Picric acid and certain ether compounds become highly explosive with age. Gases, vapors, and finely divided particulates, when confined, can also explode if an ignition source is present.

C. Toxic Hazards 1. Toxicity Toxic material cause local or systemic detrimental effects in an organism.

Exposure to such materials does not always result in death, although that is often the most immediate concern. Types of toxic hazards can be categorized by the physiological effect they have on the organism. A material may induce more than one physiological response that may include: asphyxiation, irritation allergic sensitization, systemic poisoning, mutagenesis, teratogenesis and carcinogenesis.

The likelihood that any of these effects will be experienced by an organism

depends not only on the inherent toxicity of the material itself (as measured by its lethal dose) but also by the magnitude of the exposure (acute or chronic) and the route of exposure (ingestion, inhalation, skin absorption.)

These concepts will be described in greater detail in a later chapter. D. Corrosive Hazards 1. Corrosion Corrosion is the process of material degradation. Upon contact, a

corrosive material may destroy body tissues, metals, plastics and other materials. Technically, corrosivity is the ability of material to increase the hydrogen ion or hydronium ion concentration of another materia; it may have the potential to transfer electron pairs to or from itself or another substance. A corrosive agent is a reactive compound or element that produces a destructive chemical change in the material upon which it is acting. Common corrosives are the halogens, acids, and bases (Table 2). Skin irritation and burns are typical results when the body contacts an acidic or basic material.

Table 2. Corrosives. _____________________________________________________________________________

38

Page 40: Chemical Hazards in Construction

Elements Acids Bromine Acetic acid Chlorine Hydrochloric acid Fluorine Hydorfluoric acid Iodine Nitric acid Ozone Sulfuric acid Bases (Caustics) Other Solvents Potassium hydroxide Acetic anhydride Sodium hydroxide Hydrazine ___________________________________________________________________________ The corrosiveness of acids and bases can be compared on the basis of

their ability to dissociate (form ions) in solution. Those that form the greatest number of hydrogen ions (H+) are the strongest acids, while those that form the most hydroxide ions (OH-) are the strongest bases. The H+ ion concentration in solution is called pH. Strong acids have a low pH (any H+ in solution) while strong bases have a high pH (few H+ in solution; many OH- in solution). The pH scale ranges from 0 to 14 as follows:

<--- increasing acidity neutral increasing basicity ---> 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Measurements of pH are valuable because they can be quickly done on-

site, providing immediate information on the corrosive hazard. 2. Practical Considerations When dealing with corrosive materials in the field, it is imperative to

determine: - How toxic is the corrosive material? Is it an irritant or does it cause

severe burns? - What kind of structural damage does it do, and what other hazards

can it lead to? For example, will it destroy containers holding other hazardous materials, releasing them into the environment?

E. Hazards Due to Chemical Reactivity 1. Reactivity Hazards A reactive material is one that can undergo a chemical reaction under

39

Page 41: Chemical Hazards in Construction

certain specified conditions. Generally, the term "reactive hazard" is used to refer to a substance that undergoes a violent or abnormal reaction in the presence of water or under normal room temperature in the absence of added heat, shock, or friction, and the water-reactive flammable solids which will spontaneously combust upon contact with water (See Table 1, p. 4).

2. Chemical Reactions A chemical reaction is the interaction of two or more substances, resulting

in chemical changes. Exothermic chemical reactions, which give off heat, can be the most dangerous. A separate source of heat is required to maintain endothermic chemical reactions. Removing the heat source stops the reaction.

The rate at which a chemical reaction occurs depends on the following

factors: - Surface area of reactants available at the reaction site; for example,

a large chunk of coal is combustible, but coal dust is explosive. - Physical state of reactant (solid, liquid or gas) - Concentration of reactants - Temperature - Pressure - Pressure of a catalyst 3. Compatibility If two or more hazardous materials remain in contact indefinitely without

reaction, they are compatible. Incompatibility, however, does not necessarily indicate a hazard. For example, acids and bases (both corrosive) react to form salts which may or may not be corrosive, and water.

Many operation on waste or accident sites involve mixing or unavoidable

contact between different hazardous materials. It is important to know ahead of time is such materials are compatible. If they are not, then any number of chemical reactions could occur. The results could range from the formation of an innocuous gas to a violent explosion. Table 3 illustrates what happens when some incompatible materials are combined.

Table 3. Hazards due to chemical reactions (incompatibilities). _________________________________________________________________________ Hazard Example

40

Page 42: Chemical Hazards in Construction

Generation of Heat Acid and water Fire Hydrogen sulfide and calcium hypochlorite Explosion Picric acid and sodium hydroxide Toxic gas or vapor production Sulfuric acid and plastic Flammable gas or vapor production Acid and metal Formation of a substance with a greater toxicity than the reactants Chlorine and ammonia Formation of shock or friction sensitive compounds Ammonia and iodine Pressurization of closed vessels Fire extinguisher Solubilization of toxic substances Hydrochloric acid and chromium Dispersal of toxic dusts and mists Phosphorus trichloride and water Violent polymerization Ammonia and acrylonitrile The identity of unknown reactants must be determined by chemical

analysis to establish compatibility. On the basis of their properties, a chemist then should be able to anticipate any chemical reactions resulting from mixing the reactants. Judging the compatibility of more than two reactants is very difficult; analysis should be performed on a one-to-one basis.

Response personnel who must determine compatibilities should refer to "A

Method for Determining the Compatibility of Hazardous Waste" (EPA 600/2-80--76), published by EPA's Office of Research and Development. Final decisions about compatibilities should only be made by an experienced chemist.

Sometimes the identity of a waste is impossible to ascertain due to money

and time constraints. In this event, simple tests must be performed to determine the nature of the material or mixture. Tests such as pH, oxidation-reduction potential, and flashpoint are useful In addition, very small amounts of the reactants may be carefully combined to determine compatibility.

41

Page 43: Chemical Hazards in Construction

4. Practical Considerations If material are compatible they may be stored together in bulk tanks or

transferred to tank trucks for ultimate disposal. It is necessary, then, to establish the compatibility of the materials through analyses prior to bulking them.

Compatibility information is also very important in evaluating an accident

involving several different hazardous materials. The ultimate handling and treatment of the materials may be partially based on such information.

F. Physical Properties of Chemicals

Chemical compounds possess inherent properties which determine the type and degree of the hazard they represent. Evaluating risks of an incident depends on understanding these properties and their relationship to the environment.

1. Solubility / Miscibility The ability of a solid, liquid, gas or vapor to dissolve in a solvent is

solubility. An insoluble substance can be physically mixed or blended in a solvent for a short time but is unchanged when it finally separates. The solubility of a substance is independent of its density or specific gravity.

The solubility of a material is important when determining its reactivity,

dispersion, mitigation, and treatment. Solubility is generally given in parts per million (ppm), percent by weight (w/v), or percent by volume (v/v).

Miscibility refers specifically to the solubility of a ligand in a solvent. This term is most often encountered when dealing with non-aqueous solutions.

2. Density and Specific Gravity The density of a substance is its mass per unit volume, commonly

expressed in grams per cubic centimeter (g/cc). The density of water is 1 g/cc, since 1 cc has a mass of 1 g.

Specific gravity (SpG) is the ratio of the density of a substance (at a given

temperature) to the density of water at the temperature of its maximum density (4 degrees C)).

Numerically, SpG is equal to the density in g/cc, but is expressed as pure

number without units. If the SpG of a substance is greater than 1 (the SpG of water), it will sink in water. The substance will float on water if its SpG is less than 1. This is important when considering mitigation and treatment methods.

42

Page 44: Chemical Hazards in Construction

3. Vapor Density The density of a gas or vapor can be compared to the density of the

ambient atmosphere. If the density of a vapor or gas is greater than that of the ambient air, then it will tend to settle to the lowest point. If vapor density is close to air density or lower, the vapor will tend to disperse in the atmosphere. Vapor density is given in relative terms similar to specific gravity.

In settling, dense vapor creates two hazards. First, if the vapor displaces

enough air to reduce the atmospheric concentration of oxygen below 16%, asphyxia may result. Second, if the vapor is toxic, then inhalation problems predominate even if the atmosphere is not oxygen deficient. If a substance is explosive and very dense, the explosive hazard may be close to the ground rather than at the breathing zone (normal sampling heights).

4. Vapor Pressure The pressure exerted by a vapor against the sides of a closed container is

called vapor pressure. It is temperature dependent. As temperature increases, so does the vapor pressure. Thus, more liquid evaporates or vaporizes. The lower the boiling point of the liquid, the greater the vapor pressure it will exert at a given temperature. Values for vapor pressure are most often given as millimeters of mercury (mmHg) at a specific temperature.

5. Boiling Point The boiling point is the temperature at which a liquid will change to a

vapor - that is, it is the temperature where the pressure of the liquid equals atmospheric pressure. The opposite change in phases is the condensation point. Handbooks usually list temperatures as degrees Celsius (C) or Fahrenheit (F). A major consideration with toxic substances is how they enter the body. With high-boiling point liquids, the most common entry is by body contact. With low-boiling point liquids, the inhalation route is the most common and serious.

6. Melting Point The temperature at which a solid changes phase to a liquid is the melting

point. This temperature is also the freezing point, since a liquid can change phase to a solid. The proper terminology depends on the direction of the phase change.

43

Page 45: Chemical Hazards in Construction

If a substance has been transported at a temperature that maintains a

sold phase, then a change in temperature may cause the solid to melt. The particular substance may exhibit totally different properties depending on the phase. One phase could be inert while the other highly reactive. Thus, it is imperative to recognize the possibility of a substance changing phase due to changes in the ambient temperature.

7. Flash Point If the ambient temperature in relation to the material of concern is right,

then it may give off enough vapor at its surface to allow ignition by an open flame or spark.

The minimum temperature at which a substance produces sufficient

flammable vapors to ignite is its flash point. If the vapor does ignite, combustion can continue as long as the temperature remains at or above the flash point.

The relative flammability of a substance is based on its flash point. An

accepted relation between the two is: Highly flammable: Flash point less than 100 deg F Moderately flammable: Flash point greater than 100 deg F but less than 200 deg F Relatively inflammable: Flash point greater than 200 deg F 8. Viscosity Viscosity is the resistance of a fluid to flow. Normally, viscosity decreases

with an increase in temperature, ie, heating a fluid makes it easier to pour. 9. Ignition Temperature The minimum temperature at which an external heat source is capable of

igniting a flammable gas/air mixture is called the ignition temperature for a specific fuel. The temperature ranges from 400-1000 deg F for typical hydrocarbon fuels and must not be confused with the flash point (see above).

10. Flammable Range The flammable range of a liquid is the concentration range, given as

percent, of the vapor in air which will support combustion. The minimum concentration (%) of fuel is termed the Lower Flammable

44

Page 46: Chemical Hazards in Construction

Limit (LFL) or Lower Explosive Limit (LEL). Similarly, UFL and UEL are used to denote the maximum concentration (%) which will ignite when mixed with air.)

HAZARDOUS SUBSTANCE IDENTIFICATION SYSTEMS I. INTRODUCTION Hazardous materials are frequently stored and transported in large quantities. An accidental release of these material presents a potential hazard to the public and environment. Such an incident can be managed more expeditiously when the hazardous material is specifically identified and characterized. Unfortunately, the contents of storage tanks or trucks may not be specifically or properly identified. Records or shipping papers may be inaccessible. Even with such information, an experienced person is needed to define the hazards and their seriousness. Because of the immediate need for information concerning a hazardous material, two systems for hazard identification have been developed. Both help responders to deal with a hazardous material incident quickly and safely, and both were devised for persons untrained in chemistry. The first is the National Fire Protection Association (NFPA) 704M System, which is used on storage tanks and smaller containers (fixed facility). The second system is used exclusively on containers and tanks transported in interstate commerce. The U.S. Department of Transportation (DOT) is responsible for this system. Its use, by way of placards and labels, is required under DOT regulations found in the Code of Federal Regulations 49 (49 CFR). II. NFPA 704M HAZARD IDENTIFICATION SYSTEM A. Description

NFPA 704M is a standardized system which uses numbers and colors on a sign to define the basic hazards of a specific material under fire conditions. Health, Flammability and Reactivity are identified and rated on a scale of 0 to 4 depending on the degree of hazard presented (Figure 1).

The ratings for individual chemicals can be found in the NFPA "Guide to Hazardous Materials". Other references such as the U.S. Coast Guard Manual, CHRIS Volume 2 and the National Safety Council's "Fundamentals of Industrial Hygiene" contain the NFPA ratings for specific chemicals. Such information can

45

Page 47: Chemical Hazards in Construction

be useful not only in emergencies but also during long-term remedial activities when extensive evaluation is required.

Figure 1. NFPA 704M Hazard Identification System

B. Summary of Hazard Ranking System 1. Health Hazard (BLUE) Rank Number: 4 Description: Materials that on very short exposure could cause death or

major residual injury even though prompt medical treatment was given. Examples: Acrylonitrile, Bromine, Parathion Rank Number: 3 Description: Materials that on short exposure could cause serious or

major residual injury even though prompt medical treatment was given. Examples: Aniline, Sodium hydroxide, Sulfuric Acid Rank Number: 2

46

Page 48: Chemical Hazards in Construction

Description: Materials that on intense or continued exposure could cause temporary incapacitation or possible residual injury unless prompt medical treatment was given.

Examples: Bromobenzene, Pyridine, Styrene Rank Number: 1 Description: Materials that on exposure would cause irritation but only

minor residual injury even if no treatment was given. Examples: Acetone, Methanol Rank Number: 0 Description: Materials that on exposure would offer no health hazard. Examples: 2. Flammability Hazard (RED) Rank Number: 4 Description: Materials that (1) rapidly or completely vaporize at

atmospheric pressure and normal ambient temperatures and burn readily or (2) are readily dispersed in air and burn readily.

Examples: 1, 3-Butadiene, Propane, Ethylene oxide Rank Number: 3 Description: Liquids and solids that can be ignited under almost all

ambient temperature conditions. Examples: Phosphorus, Acrylonitrile Rank Number: 2 Description: Materials that must be moderately heated or exposed to

relatively high ambient temperatures before ignition can occur.

13

47

Page 49: Chemical Hazards in Construction

Examples: 2-Butanone, Kerosene Rank Number: 1 Description: Materials that must be pre-heated before ignition can occur. Examples: Sodium, Red phosphorus Rank Number: 0 Description: Materials that will not burn. Examples: 3. Flammability Hazard (RED) Rank Number: 4

Description: Materials that in themselves are readily capable of detonation or of explosive decomposition or reaction at normal temperatures and pressures.

Examples: Benzoyl peroxide, Picric acid, TNT Rank Number: 3 Description: Materials that (1) in themselves are capable of detonation or

explosive reaction but require a strong initiating source or (2) must be heated under confinement before initiation or (3) react explosively with water.

Examples: Diborane, Ethylene oxide, 2-Nitropropadene Rank Number: 2 Description: Materials that (1) in themselves are normally unstable and

readily undergo violent chemical change but do not detonate or (2) may react violently with water or (3) may form potentially explosive mixtures with water.

14

48

Page 50: Chemical Hazards in Construction

Examples: Acetaldehyde, Potassium Rank Number: 1 Description: Materials that in themselves are normally stable but which

can (1) become unstable at elevated temperatures or (2) react with water with some release of energy but not violently.

Examples: Ethyl ether, Sulfuric Acid Rank Number: 0 Description: Materials that in themselves are normally stable, even when

exposed to fire, and that do not react with water. Examples: 4. Special Information (WHITE) The white block is designated for special information about the chemical.

For example, it may indicate that the material is radioactive by displaying the standard radioactive symbol, or unusually water-reactive by displaying a large W with a slash through it (W). For a more complete discussion of these various hazards, consult the NFPA Standard 704M.

III. DOT HAZARD IDENTIFICATION SYSTEM The DOT's Hazardous Materials Transportation Administration regulates over 1,400 hazardous materials. The regulations require labels on small containers and placards on tanks and trailers. These placards and labels indicate the nature of the hazard presented by the cargo. The classification used for the placards and labels is based on the United Nations Hazard Classes (Table 1). The UN hazard class number is found in the bottom corner of a DOT placard or label. The various hazards are defined in Table 2 at the end of this section. Also shown is a color chart of the current DOT placards and labels.

15

49

Page 51: Chemical Hazards in Construction

Table 1. UN Hazard Class System. United Nations Hazard Class Number Description _____________________________________________________________________________ 1 Explosives 2 Compressed gases 3 Flammable liquids 4 Flammable solids, spontaneously combustible substances and water-reactive substances 5 Oxidizing materials, including organic peroxides 6 Poisons, irritants and etiologic (disease-causing) materials 7 Radioactive materials 8 Corrosive materials (acids, alkaline liquids and certain corrosive liquids and solids)

9 Miscellaneous hazardous materials not covered by any of the other classes

_____________________________________________________________________________ To facilitate handling a hazardous material incident some placards are being altered to accept a 4-digit identification number (Figure 2). This number comes from the Hazardous Material Table in the DOT regulations, 49 CFR 172.101. This ID number also must be written on the shipping papers or manifest. In the event of an incident, the ID number on the placard will be much easier to obtain than the shipping papers. Once the number is obtained, the DOT's "Emergency Response Guide Book" can be consulted. This book describes the proper methods and precautions for responding to a release of each hazardous material with an ID number. The DOT system goes one step further in aiding response personnel than the NFPA system. However, using both systems when responding to hazardous material incidents will help to properly identify and characterize the materials involved.

16

50

Page 52: Chemical Hazards in Construction

Asbestos in the

Construction Industry

51

Page 53: Chemical Hazards in Construction

1

Introduction

What is asbestos?

Asbestos is the generic term for a group of naturallyoccurring, fibrous minerals with high tensile strength,flexibility, and resistance to heat, chemicals, and electricity.

In the construction industry, asbestos is found in installedproducts such as sprayed-on fireproofing, pipe insulation,floor tiles, cement pipe and sheet, roofing felts and shingles,ceiling tiles, fire-resistant drywall, drywall joint compounds,and acoustical products. Because very few asbestos-containing products are being installed today, most workerexposures occur during the removal of asbestos and therenovation and maintenance of buildings and structurescontaining asbestos.

What are the dangers of

asbestos exposure?

Asbestos fibers enter the body when a person inhalesor ingests airborne particles that become embedded in thetissues of the respiratory or digestive systems. Exposureto asbestos can cause disabling or fatal diseases such asasbestosis, an emphysema-like condition; lung cancer;mesothelioma, a cancerous tumor that spreads rapidly inthe cells of membranes covering the lungs and body organs;and gastrointestinal cancer. The symptoms of these diseasesgenerally do not appear for 20 or more years after initialexposure.

What construction activities

does this booklet cover?

The asbestos standard for the construction industry(29 CFR Part 1926.1101, see www.osha.gov) regulatesasbestos exposure for the following activities:

■ Demolishing or salvaging structures where asbestos ispresent.

52

Page 54: Chemical Hazards in Construction

2

■ Removing or encapsulating asbestos-containing material(ACM).

■ Constructing, altering, repairing, maintaining, orrenovating asbestos-containing structures or substrates.

■ Installing asbestos-containing products.

■ Cleaning up asbestos spills/emergencies.

■ Transporting, disposing, storing, containing, andhousekeeping involving asbestos or asbestos-containingproducts on a construction site.

Note: The standard does not apply to asbestos-containingasphalt roof coatings, cements, and mastics.

53

Page 55: Chemical Hazards in Construction

3

Provisions ofthe OSHA Standard

OSHA has established strict exposure limits andrequirements for exposure assessment, medical surveillance,recordkeeping, competent persons, regulated areas, andhazard communication.

What is work classification?

The OSHA standard establishes a classification systemfor asbestos construction work that spells out mandatory,simple, technological work practices that employers mustfollow to reduce worker exposures. Under this system, thefollowing four classes of construction work are matchedwith increasingly stringent control requirements:

■ Class I asbestos work is the most potentially hazardousclass of asbestos jobs. This work involves the removalof asbestos-containing thermal system insulation andsprayed-on or troweled-on surfacing materials. Employersmust presume that thermal system insulation and surfacingmaterial found in pre-1981 construction is ACM. Thatpresumption, however, is rebuttable. If you believe thatthe surfacing material or thermal system insulation is notACM, the OSHA standard specifies the means that youmust use to rebut that presumption. Thermal systeminsulation includes ACM applied to pipes, boilers, tanks,ducts, or other structural components to prevent heat lossor gain. Surfacing materials include decorative plaster onceilings and walls; acoustical materials on decking, walls,and ceilings; and fireproofing on structural members.

■ Class II work includes the removal of other types of ACMthat are not thermal system insulation such as resilientflooring and roofing materials. Examples of Class II workinclude removal of asbestos-containing floor or ceiling tiles,siding, roofing, or transite panels.

■ Class III asbestos work includes repair and maintenanceoperations where ACM or presumed ACM (PACM) aredisturbed.

54

Page 56: Chemical Hazards in Construction

4

■ Class IV work includes custodial activities where employeesclean up asbestos-containing waste and debris produced byconstruction, maintenance, or repair activities. This workinvolves cleaning dust-contaminated surfaces, vacuumingcontaminated carpets, mopping floors, and cleaning upACM or PACM from thermal system insulation orsurfacing material.

What is the permissible

exposure limit for asbestos?

Employers must ensure that no employee is exposed to anairborne concentration of asbestos in excess of 0.1 f/cc as an8-hour time-weighted average (TWA). In addition, employeesmust not be exposed to an airborne concentration of asbestosin excess of 1 f/cc as averaged over a sampling period of30 minutes.

Which asbestos operations must

employers monitor and assess?

Employers must assess all asbestos operations for thepotential to generate airborne fibers, and use exposuremonitoring data to assess employee exposures. You must alsodesignate a competent person to help ensure the safety andhealth of your workers.

What is the function of a

competent person?

On all construction sites with asbestos operations,employers must designate a competent person—one whocan identify asbestos hazards in the workplace and has theauthority to correct them. This person must be qualified andauthorized to ensure worker safety and health as requiredby Subpart C, General Safety and Health Provisionsfor Construction (29 CFR Part 1926.20). Under these

55

Page 57: Chemical Hazards in Construction

5

requirements for safety and health prevention programs, thecompetent person must frequently inspect job sites, materials,and equipment.

The competent person must attend a comprehensivetraining course for contractors and supervisors certified bythe U.S. Environmental Protection Agency (EPA) or a state-approved training provider, or a complete a course that isequivalent in length and content.

For Class III and IV asbestos work, training must includea course equivalent in length, stringency, and content to the16-hour Operations and Maintenance course developed byEPA for maintenance and custodial workers. For morespecific information, see 40 CFR Part 763.92(a)(2).

What is an initial exposure assessment?

To determine expected exposures, a competent personmust perform an initial exposure assessment to assessexposures immediately before or as the operation begins.This person must perform the assessment in time to complywith all standard requirements triggered by exposure dataor the lack of a negative exposure assessment and to providethe necessary information to ensure all control systemsare appropriate and work properly. A negative exposureassessment demonstrates that employee exposure duringan operation is consistently below the permissible exposurelimit (PEL).

The initial exposure assessment must be based on thefollowing criteria:

■ Results of employee exposure monitoring, unless a negativeexposure assessment has been made; and

■ Observations, information, or calculations indicatingemployee exposure to asbestos, including any previousmonitoring.

56

Page 58: Chemical Hazards in Construction

6

For Class I asbestos work, until employers document thatemployees will not be exposed in excess of the 8-hour TWAPEL and short-term exposure limit STEL, employers mustassume that employee exposures are above those limits.

What is a negative exposure assessment?

For any specific asbestos job that trained employeesperform, employers may show that exposures will be belowthe PELs (i.e., negative exposure assessment) through thefollowing:

■ Objective data demonstrating that ACM, or activitiesinvolving it, cannot release airborne fibers in excess of the8-hour TWA PEL or STEL;

■ Exposure data obtained within the past 12 months fromprior monitoring of work operations closely resembling theemployer’s current work operations (the work operationsthat were previously monitored must have been conductedby employees whose training and experience were no moreextensive than that of current employees, and the data mustshow a high degree of certainty that employee exposureswill not exceed the 8-hour TWA PEL or STEL under currentconditions); or

■ Current initial exposure monitoring that used breathingzone air samples representing the 8-hour TWA and 30-minute short-term exposures for each employee in thoseoperations most likely to result in exposures over the 8-hourTWA PEL for the entire asbestos job.

Are employers required to perform

exposure monitoring?

Yes. Employers must determine employee exposuremeasurements from breathing zone air samples representingthe 8-hour TWA and 30-minute short-term exposures foreach employee.

57

Page 59: Chemical Hazards in Construction

7

Employers must take one or more samples representingfull-shift exposure to determine the 8-hour TWA exposurein each work area. To determine short-term employeeexposures, you must take one or more samples representing30-minute exposures for the operations most likely to exposeemployees above the excursion limit in each work area.

You must also allow affected employees and theirdesignated representatives to observe any employee exposuremonitoring. When observation requires entry into a regulatedarea, you must provide and require the use of protectiveclothing and equipment.

When must employers conduct

periodic monitoring?

For Class I and II jobs, employers must conductmonitoring daily that is representative of each employeeworking in a regulated area, unless you have produced anegative exposure assessment for the entire operation andnothing has changed. When all employees use supplied-airrespirators operated in positive-pressure mode, however, youmay discontinue daily monitoring. When employees performClass I work using control methods not recommended in thestandard, you must continue daily monitoring even whenemployees use supplied-air respirators.

For operations other than Class I and II, employers mustmonitor all work where exposures can possibly exceed thePEL often enough to validate the exposure prediction.

If periodic monitoring shows that certain employeeexposures are below the 8-hour TWA PEL and the STEL,you may discontinue monitoring these employees’ exposures.

58

Page 60: Chemical Hazards in Construction

8

Is additional monitoring ever needed?

Changes in processes, control equipment, personnel,or work practices that could result in new or additionalexposures above the 8-hour TWA PEL or STEL requireadditional monitoring regardless of a previous negativeexposure assessment for a specific job.

Are employers required to establish

medical surveillance programs for

employees?

It depends. Employers must provide a medical surveillanceprogram for all employees who do the following:

■ Engage in Class I, II, or III work or are exposed at orabove the PEL or STEL for a combined total of 30 or moredays per year; or

■ Wear negative-pressure respirators.

In addition, a licensed physician must perform or superviseall medical exams and procedures that you provide at no costto your employees and at a reasonable time.

Employers must make medical exams and consultationsavailable to employees as follows:

■ Prior to employee assignment to an area where negative-pressure respirators are worn;

■ Within 10 working days after the 30th day of combinedengagement in Class I, II, and III work and exposure ator above a PEL, and at least annually thereafter; and

■ When an examining physician suggests them morefrequently.

If an employee was examined within the past 12 monthsand that exam meets the criteria of the standard, however,another medical exam is not required.

59

Page 61: Chemical Hazards in Construction

9

Medical exams must include the following:

■ Medical and work histories;

■ Completion of a standardized questionnaire with the initialexam (see 29 CFR Part 1926.1101, Appendix D, Part 1)and an abbreviated standardized questionnaire with annualexams (see 29 CFR Part 1926.1101, Appendix D, Part 2);

■ Physical exam focusing on the pulmonary andgastrointestinal systems; and

■ Any other exams or tests deemed necessary by theexamining physician.

Employers must provide the examining physician withthe following:

■ Copy of OSHA’s asbestos standard and its appendices D,E, and I;

■ Description of the affected employee’s duties relating toexposure;

■ Employee’s representative exposure level or anticipatedexposure level;

■ Description of any personal protective equipment andrespiratory equipment used; and

■ Information from previous medical exams not otherwiseavailable.

It is the employer’s responsibility to obtain the physician’swritten opinion containing results of the medical exam as wellas the following information:

■ Any medical conditions of the employee that increase healthrisks from asbestos exposure.

■ Any recommended limitations on the employee orprotective equipment used.

60

Page 62: Chemical Hazards in Construction

10

■ A statement that the employee has been informed of theresults of the medical exam and any medical conditionsresulting from asbestos exposure.

■ A statement that the employee has been informed of theincreased risk of lung cancer from the combined effect ofsmoking and asbestos exposure.

Note: A physician’s written opinion must not revealspecific findings or diagnoses unrelated to occupationalexposure to asbestos. You must provide a copy of thephysician’s written opinion to the employee involved within30 days after receipt.

Do employers have to keep

any employee records?

Yes. Employers must maintain employee recordsconcerning objective data, exposure monitoring, and medicalsurveillance.

If using objective data to demonstrate that productsmade from or containing asbestos cannot release fibers inconcentrations at or above the PEL or STEL, employers mustkeep an accurate record for as long as it is relied on andinclude the following information:

■ Exempt products.

■ Objective data source.

■ Testing protocol, test results, and analysis of the materialfor release of asbestos.

■ Exempt operation and support data descriptions.

■ Relevant data for operations, materials, processes, oremployee exposures.

61

Page 63: Chemical Hazards in Construction

11

Employers must keep records of all employee exposuremonitoring for at least 30 years, including followinginformation:

■ Date of measurement.

■ Operation involving asbestos exposure that you monitored.

■ Methods of sampling and analysis that you used andevidence of their accuracy.

■ Number, duration, and results of samples taken.

■ Type of protective devices worn.

■ Name, social security number, and exposures of theemployees involved.

Employers must also make exposure records availablewhen requested to affected employees, former employees,their designated representatives, and/or OSHA’s AssistantSecretary.

In addition to retaining a copy of the information providedto the examining physician, employers must keep all medicalsurveillance records for the duration of an employee’semployment plus 30 years, including the followinginformation:

■ Employee’s name and social security number.

■ Employee’s medical exam results, including the medicalhistory, questionnaires, responses, test results, andphysician’s recommendations.

■ Physician’s written opinions.

■ Employee’s medical complaints related to asbestosexposure.

62

Page 64: Chemical Hazards in Construction

12

Employers must also make employees’ medicalsurveillance records available to them, as well as to anyonehaving specific written consent of an employee, and toOSHA’s Assistant Secretary.

Also, employers must maintain other records. Employersmust maintain all employee training records for 1 yearbeyond the last date of employment.

If data demonstrate ACM does not contain asbestos,building owners or employers must keep associated recordsfor as long as they rely on them. Building owners mustmaintain written notifications on the identification, location,and quantity of any ACM or PACM for the duration ofownership, and transfer the records to successive owners.

When employers cease to do business without a successorto keep their records, employers must notify the Director ofthe National Institute for Occupational Safety and Health(NIOSH) at least 90 days prior to their disposal and transmitthem as requested.

What is a regulated area?

A regulated area is a marked-off site where employeeswork with asbestos, including any adjoining areas wheredebris and waste from asbestos work accumulates or whereairborne concentrations of asbestos exceed, or can possiblyexceed, the PEL.

All Class I, II, and III asbestos work, or any otheroperations where airborne asbestos exceeds the PEL, mustbe performed within regulated areas. Only persons permittedby an employer and required by work duties to be present inregulated areas may enter a regulated area. The designatedcompetent person supervises all asbestos work performed inthis area.

Employers must mark off the regulated area in a mannerthat minimizes the number of persons within the area and

63

Page 65: Chemical Hazards in Construction

13

protects persons outside the area from exposure to airborneasbestos. You may use critical barriers (i.e., plastic sheetingplaced over all openings to the work area to prevent airborneasbestos from migrating to an adjacent area) or negative-pressure enclosures to mark off a regulated area.

Posted warning signs demarcating the area must be easilyreadable and understandable. The signs must bear thefollowing information:

DANGER

ASBESTOS

CANCER AND LUNG DISEASE HAZARD

AUTHORIZED PERSONNEL ONLY

RESPIRATORY AND PROTECTIVE CLOTHINGARE REQUIRED IN THIS AREA

Employers must supply a respirator to all persons enteringregulated areas. (See respiratory protection requirementselsewhere in this booklet.) Employees must not eat, drink,smoke, chew (tobacco or gum), or apply cosmetics inregulated areas.

An employer performing work in a regulated area mustinform other employers onsite of the following:

■ Nature of the work,

■ Regulated area requirements, and

■ Measures taken to protect onsite employees.

The contractor creating or controlling the sourceof asbestos contamination must abate the hazards.All employers with employees working near regulatedareas, must daily assess the enclosure’s integrity or theeffectiveness of control methods to prevent airborneasbestos from migrating.

64

Page 66: Chemical Hazards in Construction

14

General contractors on a construction project mustoversee all asbestos work, even though they may not be thedesignated competent person. As supervisor of the entireproject, the general contractor determines whether asbestoscontractors comply with the standard and ensures that theycorrect any problems.

Who is responsible for communicating

asbestos hazards at worksites?

The communication of asbestos hazards is vital to preventfurther overexposure. Most asbestos-related constructioninvolves previously installed building materials. Building/facility owners often are the only or best source ofinformation concerning these materials.

Building/facility owners, as well as employers of workerswho may be exposed to asbestos hazards, have specific dutiesunder the standard.

Before work begins, building/facility owners must identifyall thermal system insulation at the worksite, sprayed ortroweled-on surfacing materials in buildings, and resilientflooring material installed before 1981. They also must notifythe following persons of the presence, location, and quantityof ACM or PACM:

■ Prospective employers applying or bidding for work in oradjacent to areas containing asbestos.

■ Building owners’ employees who work in or adjacent tothese areas.

■ Other employers on multi-employer worksites withemployees working in or adjacent to these areas.

■ All tenants who will occupy the areas containing ACM.

65

Page 67: Chemical Hazards in Construction

15

Employers discovering ACM on a worksite must notifythe building/facility owner and other employers onsitewithin 24 hours regarding its presence, location, and quantity.You also must inform owners and employees working innearby areas of the precautions taken to confine airborneasbestos. Within 10 days of project completion, you mustinform building/facility owners and other employers onsiteof the current locations and quantities of remaining ACMand any final monitoring results.

At any time, employers or building and facility ownersmay demonstrate that a PACM does not contain asbestos byinspecting the material in accordance with the requirementsof the Asbestos Hazard Emergency Response Act (AHERA)(40 CFR Part 763, Subpart E) or by performing tests of bulksamples collected in the manner described in 40 CFR Part763.86. (See 29 CFR Part 1926.1101 for specific testingrequirements.)

Employers do not have to inform employees of asbestos-free building materials present; however, you must retain theinformation, data, and analysis supporting the determination.(See recordkeeping requirements elsewhere in this publicationfor more specific information.)

Does the OSHA standard require

the posting of warning signs?

Yes. At the entrance to mechanical rooms or areas withACM or PACM, the building/facility owner must post signsidentifying the material present, its specific location, andappropriate work practices that ensure it is not disturbed.

Also, employers must post warning signs in regulatedareas to inform employees of the dangers and necessaryprotective steps to take before entering. (See the regulatedarea requirements elsewhere in this publication.)

66

Page 68: Chemical Hazards in Construction

16

Must employers provide asbestos

warning labels?

Employers must attach warning labels to all products andcontainers of asbestos, including waste containers, and allinstalled asbestos products, when possible. Labels must beprinted in large, bold letters on a contrasting background andused in accordance with OSHA’s Hazard CommunicationStandard (29 CFR Part1910.1200). All labels must containa warning statement against breathing asbestos fibers andcontain the following legend:

DANGER

CONTAINS ASBESTOS FIBERS

AVOID CREATING DUST

CANCER AND LUNG DISEASE HAZARD

Labels are not required if asbestos is present inconcentrations less than 1 percent by weight. They also arenot required if bonding agents, coatings, or binders havealtered asbestos fibers, prohibiting the release of airborneasbestos over the PEL or STEL during reasonable use,handling, storage, disposal, processing, or transportation.

When building owners or employers identify previouslyinstalled asbestos or PACM, employers must attach or postclearly noticeable and readable labels or signs to informemployees which materials contain asbestos.

Do employers have to train employees

regarding asbestos exposure?

Yes. Employers must provide a free training program forall employees who are likely to be exposed in excess of a PELand for all employees performing Class I through IV asbestosoperations. Employees must be trained prior to or at initialassignment and at least annually thereafter. Training courses

67

Page 69: Chemical Hazards in Construction

17

must be easily understandable and include the followinginformation:

■ Ways to recognize asbestos.

■ Adverse health effects of asbestos exposure.

■ Relationship between smoking and asbestos in causinglung cancer.

■ Operations that could result in asbestos exposure and theimportance of protective controls to minimize exposure.

■ Purpose, proper use, fitting instruction, and limitations ofrespirators.

■ Appropriate work practices for performing asbestos jobs.

■ Medical surveillance program requirements.

■ Contents of the standard.

■ Names, addresses, and phone numbers of public healthorganizations that provide information and materials orconduct smoking cessation programs.

■ Sign and label requirements and the meaning of theirlegends.

■ Written materials relating to employee training and self-help smoking cessation programs at no cost to employees.

Also, the following additional training requirements applydepending on the work class involved:

■ For Class I operations and for Class II operations thatrequire the use of critical barriers (or equivalent isolationmethods) and/or negative pressure enclosures, trainingmust be equivalent in curriculum, method, and length to theEPA Model Accreditation Plan (MAP) asbestos abatementworker training (see 40 CFR Part 763, Subpart E,Appendix C).

68

Page 70: Chemical Hazards in Construction

18

■ For employees performing Class II operations involving onegeneric category of building materials containing asbestos(e.g., roofing, flooring, or siding materials or transitepanels), training may be covered in an 8-hour course thatincludes hands-on experience.

■ For Class III operations, training must be equivalent incurriculum and method to the 16-hour Operations andMaintenance course developed by EPA for maintenance andcustodial workers whose work disturbs ACM (see 40 CFRPart 763.92). The course must include hands-on training onproper respirator use and work practices.

■ For Class IV operations, training must be equivalent incurriculum and method to EPA awareness training (see 29CFR Part1926.1101 for more information). Training mustfocus on the locations of ACM or PACM and the ways torecognize damage and deterioration and avoid exposure.The course must be at least 2 hours in length.

Note: Employers must provide OSHA’s AssistantSecretary and the Director of NIOSH all information andtraining materials as requested.

69

Page 71: Chemical Hazards in Construction

19

Methods of Compliance

What methods must employers use to

control asbestos exposure levels?

For all covered work, employers must use the followingcontrol methods to comply with the PEL and STEL:

■ Local exhaust ventilation equipped with HEPA-filter dustcollection systems (a high-efficiency particulate air [HEPA]filter is capable of trapping and retaining at least 99.97percent of all mono-dispersed particles of 0.3 micrometersin diameter).

■ Enclosure or isolation of processes producing asbestos dust.

■ Ventilation of the regulated area to move contaminated airaway from the employees’ breathing zone and toward afiltration or collection device equipped with a HEPA filter.

■ Feasible engineering and work practice controls to reduceexposure to the lowest possible levels, supplemented byrespirators to reach the PEL or STEL or lower.

Employers must use the following engineering controlsand work practices for all operations regardless of exposurelevels:

■ Vacuum cleaners equipped with HEPA filters to collect allasbestos-containing or presumed asbestos-containing debrisand dust.

■ Wet methods or wetting agents to control employeeexposures except when infeasible (e.g., due to the creationof electrical hazards, equipment malfunction, and slippinghazards).

■ Prompt cleanup and disposal in leak-tight containers ofasbestos-contaminated wastes and debris.

70

Page 72: Chemical Hazards in Construction

20

The following work practices and engineering controls areprohibited for all asbestos-related work or work that disturbsasbestos or PACM regardless of measured exposure levels orthe results of initial exposure assessments:

■ High-speed abrasive disc saws not equipped with apoint-of-cut ventilator or enclosure with HEPA-filteredexhaust air.

■ Compressed air to remove asbestos or ACM unless thecompressed air is used with an enclosed ventilation system.

■ Dry sweeping, shoveling, or other dry cleanup of dustand debris.

■ Employee rotation to reduce exposure.

In addition, OSHA’s asbestos standard has specificrequirements for each class of asbestos work in construction.

What are the compliance requirements

for Class I work?

A designated competent person must supervise all Class Iwork, including installing and operating the control system.The competent person must inspect onsite at least once duringeach work shift and upon employee request.

Employers must place critical barriers over all openings toregulated areas or use another barrier or isolation method toprevent airborne asbestos from migrating for the followingjobs:

■ All Class I jobs removing more than 25 linear or 10 squarefeet of thermal system insulation or surfacing material.

■ All other Class I jobs without a negative exposureassessment.

■ All jobs where employees are working in areas adjacent toa Class I regulated area.

71

Page 73: Chemical Hazards in Construction

21

If using other barriers or isolation methods instead ofcritical barriers, employers must perform perimeter areasurveillance during each work shift. No asbestos dust shouldbe visible. Perimeter monitoring must show that clearancelevels are met (as contained in 40 CFR Part 763, Subpart Eof the EPA Asbestos in Schools rule) or that perimeter arealevels are no greater than background levels.

Employers must ensure the following for all Class I jobs:

■ Isolating heating, ventilating, and air-conditioning (HVAC)systems in regulated areas by sealing with a double layerof 6 mil plastic or the equivalent.

■ Placing impermeable drop cloths on surfaces beneath allremoval activity.

■ Covering and securing all objects within the regulatedarea with impermeable drop cloths or plastic sheeting.

■ Ventilating the regulated area to move the contaminatedair away from the employee breathing zone and towarda HEPA filtration or collection device for jobs withouta negative exposure assessment or where exposuremonitoring shows the PEL is exceeded.

In addition, employees performing Class I work must useone or more of the following control methods:

■ Negative-pressure enclosure systems when theconfiguration of the work area does not make it infeasibleto erect the enclosure.

■ Glove bag systems to remove ACM or PACM from piping.

■ Negative-pressure glove bag systems to remove asbestos orPACM from piping.

■ Negative-pressure glove box systems to remove asbestos orACM from pipe runs.

72

Page 74: Chemical Hazards in Construction

22

■ Water spray process systems to remove asbestos or PACMfrom cold-line piping if employees carrying out the processhave completed a 40-hour training course on its use inaddition to training required for all employees performingClass I work.

■ Small walk-in enclosure that accommodates no more than2 people (mini-enclosure) if the disturbance or removal canbe completely contained by the enclosure.

For the specifications, limitations, and recommendedwork practices of these required control methods, refer toOccupational Exposure to Asbestos, 29 CFR Part 1926.1101.

Employers may use different or modified engineeringand work practice controls if they adhere to the followingprovisions:

■ Control method encloses, contains, or isolates the processor source of airborne asbestos dust, or captures andredirects the dust before it enters into the employees’breathing zone.

■ Certified industrial hygienist or licensed professionalengineer qualified as a project designer evaluates the workarea, the projected work practices, and the engineeringcontrols and certifies, in writing, that based on evaluationsand data the planned control method adequately reducesdirect and indirect employee exposure to or below the PELunder worst-case conditions. The planned control methodalso must prevent asbestos contamination outside theregulated area, as measured by sampling meeting therequirements of the EPA Asbestos in Schools rule orperimeter monitoring.

■ Employer sends a copy of the evaluation and certificationto the OSHA National Office, Office of Technical Support,Room N3653, 200 Constitution Avenue, N.W., Washington,DC 20210, before using alternative methods to remove

73

Page 75: Chemical Hazards in Construction

23

more than 25 linear or 10 square feet of thermal systeminsulation or surfacing material.

What are the compliance requirements

for Class II work?

In addition to all indoor Class II jobs without a negativeexposure assessment, employers must use critical barriersover all openings to the regulated area or another barrier orisolation method to prevent airborne asbestos from migratingfor the following:

■ When changing conditions indicate exposure above thePEL, or

■ When ACM is not removed substantially intact.

If using other barriers or isolation methods instead ofcritical barriers, employers must perform perimeter areamonitoring to verify that the barrier works properly. Inaddition, impermeable drop cloths must cover all surfacesbeneath removal activities.

All Class II asbestos work can use the same workpractices and requirements as Class I asbestos jobs.Alternatively, Class II work can be performed using workpractices set out in the standard for specific jobs.

For removing vinyl and asphalt flooring materialscontaining asbestos or installed in buildings constructedbefore 1981 and not verified as asbestos-free, employers mustensure that workers observe the following:

■ Do not sand flooring or its backing,

■ Do not rip up resilient sheeting,

■ Do not dry sweep,

■ Perform mechanical chipping only in a negative-pressureenclosure,

74

Page 76: Chemical Hazards in Construction

24

■ Use vacuums equipped with HEPA filters to clean floors,

■ Remove resilient sheeting by cutting with wetting of thesnip point and wetting during delamination,

■ Use wet methods to scrape residual adhesives and/orbacking,

■ Remove tiles intact, unless impossible (you may omitwetting when tiles are heated and removed intact), and

■ Assume resilient flooring material—including associatedmastic and backing—is asbestos-containing unless anindustrial hygienist determines that it is asbestos-free.

To remove asbestos-containing roofing materials,employers must ensure that workers do the following:

■ Remove them intact if feasible,

■ Use wet methods when intact removal is infeasible, and

■ Mist cutting machines continuously during use, unless thecompetent person determines misting to be unsafe.

When removing built-up roofs using a power roof cutteremployers must ensure that workers observe the followingprocedures:

■ Use power cutters equipped with HEPA dust collectors orperform HEPA vacuuming along the cut line for roofs thathave asbestos-containing roofing felts and an aggregatesurface.

■ Use power cutters equipped with HEPA dust collectors,or perform HEPA vacuuming along the cut line, or gentlysweep along the cut line and then carefully and completelywipe up the still-wet dust and debris that was acquired forroofs that have asbestos-containing roofing felts and asmooth surface.

75

Page 77: Chemical Hazards in Construction

25

■ Do not drop or throw to the ground ACM that has beenremoved from a roof.

■ Carry or pass the ACM to the ground by hand, or lowerthe material to the ground via covered, dust-tight chute,crane or hoist.

■ Lower both intact ACM and non-intact ACM to theground as soon as it is practicable, but no later than theend of the work shift.

■ Keep material wet if it is not intact, or place it inimpermeable waste bags, or wrap it in plastic sheetingwhile it remains on the roof.

■ Lower to the ground, as soon as possible or by the endof the work shift, any unwrapped or unbagged roofingmaterial using a covered, dust-tight chute, crane, or hoist.

■ Place unwrapped materials in closed containers to preventscattering dust after the materials reach the ground.

■ Isolate roof level heating and ventilation air intake sourcesor shut down the ventilation system.

When removing cement-like asbestos-containing siding orshingles, or asbestos-containing transite panels on buildingexteriors other than roofs, employers must ensure thatemployees adhere to the following:

■ Do not cut, abrade, or break siding, shingles, or transitepanels unless methods less likely to result in asbestos fiberrelease cannot be used;

■ Spray each panel or shingle with amended water beforeremoving (amended water is water to which a surfactant[wetting agent] has been added to increase the ability ofthe liquid to penetrate ACM);

76

Page 78: Chemical Hazards in Construction

26

■ Lower immediately to the ground any unwrapped orunbagged panels or shingles using a covered dust-tightchute, crane, or hoist, or place them in an imperviouswaste bag or wrap them in plastic sheeting and lower themto the ground no later than the end of the work shift; and

■ Cut nails with flat, sharp instruments.

When removing asbestos-containing gaskets, employersmust ensure that employees do the following:

■ Remove gaskets within glove bags if they are visiblydeteriorated and unlikely to be removed intact;

■ Wet the gaskets thoroughly with amended water prior toremoving;

■ Place the wet gaskets in a disposal container immediately;and

■ Keep the residue wet if removed by scraping.

For removal of any other Class II ACM, employers mustensure that employees observe the following:

■ Do not cut, abrade, or break the material unless infeasible;

■ Wet the material thoroughly with amended water beforeand during removal;

■ Remove the material intact, if possible; and

■ Bag or wrap removed ACM immediately or keep it wetuntil transferred to a closed receptacle no later than the endof the work shift.

Employers may use different or modified engineering andwork practice controls under the following conditions:

■ If they can demonstrate that employee exposure will notexceed the PEL under any anticipated circumstances; and

77

Page 79: Chemical Hazards in Construction

27

■ If a competent person evaluates the work area, theprojected work practices, and the engineering controls andcertifies, in writing, that these different or modified controlswill reduce all employee exposure to or below the PELsunder all expected conditions of use and that they meetthe requirements of the standard. This evaluation mustinclude, and be based on, data representing employeeexposure during use of the controls under conditions closelyresembling those of the current job. Also, the employeesparticipating in the evaluation must not have better trainingand more experience than that of the employees who are toperform the current job.

What are the compliance requirements

for Class III work?

Employers must use wet methods and local exhaustventilation, to the extent feasible, during Class III work.When drilling, cutting, abrading, sanding, chipping, breaking,or sawing of asbestos-containing thermal system insulation orsurfacing materials occurs, employers must use impermeabledrop cloths as well as mini-enclosures, glove bag systems, orother effective isolation methods and ensure that workerswear respirators. If the material is not thermal systeminsulation or surfacing material and a negative exposureassessment has not been produced or monitoring showsthe PEL is exceeded, employers must contain the areawith impermeable drop cloths and plastic barriers orother isolation methods and ensure that employees wearrespirators. (See also respirator requirements elsewhere inthis publication.) In addition, the competent person mustinspect often enough to assess changing conditions andupon employee request.

78

Page 80: Chemical Hazards in Construction

28

What are the compliance requirements

for Class IV work?

Employees conducting Class IV asbestos work musthave attended an asbestos awareness training program.They must use wet methods and HEPA vacuums to promptlyclean asbestos-containing or presumed asbestos-containingdebris. When cleaning debris and waste in regulated areas,employees must wear respirators. In areas where thermalsystem insulation or surfacing material is present, workersmust assume that all waste and debris contain asbestos.

Does the competent person have duties

that apply to more than one work class?

Yes. For Class II, III, and IV jobs, the competent personmust inspect often enough to assess changing conditions andupon employee request.

For Class I or II asbestos work, the competent personmust ensure the integrity of the enclosures or othercontainments by onsite inspection and supervise thefollowing activities:

■ Setup of regulated areas, enclosures, or other containments.

■ Setup procedures to control entry to and exit from theenclosure or area.

■ Employee exposure monitoring by ensuring it is properlyconducted.

■ Use of required protective clothing and equipment byemployees working within the enclosure or using glovebags (a plastic bag-like enclosure affixed around ACM,with glove-like appendages through which materials andtools may be handled).

■ Setup, removal, and performance of engineering controls,work practices, and personal protective equipment throughonsite inspection.

79

Page 81: Chemical Hazards in Construction

29

■ Use of hygiene facilities by employees.

■ Required decontamination procedures.

■ Notification requirements.

What does the OSHA standard require

concerning respirators?

Employees must use respirators during the followingactivities:

■ Class I asbestos jobs.

■ Class II work where ACM is not removed substantiallyintact.

■ Class II and III work not using wet methods.

■ Class II and III work without a negative exposureassessment.

■ Class III jobs where thermal system insulation or surfacingACM or PACM is cut, abraded, or broken.

■ Class IV work within a regulated area where respiratorsare required.

■ Work where employees are exposed above the TWA orexcursion limit.

■ Emergencies.

Employers must provide respirators at no cost to workers,selecting the appropriate type from among those certified byNIOSH.

Employers must provide employees performing Class Iwork with full-facepiece supplied air respirators operatedin pressure-demand mode and equipped with an auxiliarypositive-pressure, self-contained breathing apparatus whenexposure levels exceed 1 f/cc as an 8-hour TWA.

80

Page 82: Chemical Hazards in Construction

30

Employers must provide half-mask purifying respirators—other than disposable respirators—equipped with high-efficiency filters for Class II and III asbestos jobs wherework disturbs thermal system insulation or surfacing ACMor PACM.

If a particular job is not Class I, II, or III and exposuresare above the PEL or STEL, the asbestos standard, 29 CFRPart 1926.1101, contains a table specifying types ofrespirators to use.

According to 29 CFR Part 1910.134, employers mustinstitute a respiratory program that includes the following:

■ Procedures for selecting respirators for use in theworkplace;

■ Fit testing procedures for tight-fitting respirators;

■ Procedures for proper use of respirators in routine andreasonably foreseeable emergency situations;

■ Procedures and schedules for cleaning, disinfecting,storing, inspecting, repairing, discarding, and maintainingrespirators;

■ Procedures to ensure adequate air quality, quantity, andflow of breathing air for atmosphere-supplying respirators;

■ Training of employees in the respiratory hazards to whichthey are potentially exposed during routine and emergencysituations;

■ Training of employees in the proper use and maintenanceof respirators, including putting on and removing them,and any limitations on their use; and

■ Procedures for regularly evaluating the effectiveness ofthe program.

(See Respiratory Protection, 29 CFR Part 1910.134, forcomplete program requirements.)

81

Page 83: Chemical Hazards in Construction

31

With regard to fit testing, employers must do thefollowing:

■ Ensure that employees are fit tested with the same make,model, style, and size of respirator that they will be using;

■ Ensure that employees using a tight-fitting facepiecerespirator pass an appropriate qualitative fit test (QLFT)or quantitative fit test (QNFT);

■ Ensure that an employee using a tight-fitting facepiecerespirator is fit tested prior to initial use of the respirator,whenever a different size, style, model or make ofrespirator facepiece is used, and at least annually thereafter.

■ Conduct an additional fit test whenever an employeereports (or the employer, physician or other licensedhealth-care professional, supervisor, or programadministrator makes) visual observations of changesin an employee’s physical condition that could affectrespirator fit. Such conditions include, but are not limitedto, facial scarring, dental changes, cosmetic surgery, oran obvious change in body weight.

Employers must not assign any employee to tasksrequiring respirator use who, based on the most recentphysical exam and the examining physician’s recommendations,would be unable to function normally. Employers must assignsuch employees to other jobs or give them the opportunity totransfer to different positions in the same geographical areaand with the same seniority, status, pay rate, and job benefitsas they had before transferring, if such positions areavailable.

Do employers have to provide

protective clothing for employees?

Employers must provide and require the use of protectiveclothing—such as coveralls or similar whole-body clothing,head coverings, gloves, and foot coverings—for the following:

82

Page 84: Chemical Hazards in Construction

32

■ Employees exposed to airborne asbestos exceeding the PELor STEL;

■ Work without a negative exposure assessment; or

■ Employees performing Class I work involving the removalof over 25 linear or 10 square feet of thermal systeminsulation or surfacing ACM or PACM.

Employers must ensure that the laundering ofcontaminated clothing does not release airborne asbestosin excess of the PEL or STEL. Employers who givecontaminated clothing to other persons for laundering mustinform them of the requirement to follow procedures that donot release airborne asbestos in excess of the PEL or STEL.

Employers must transport contaminated clothing in sealed,impermeable bags or other closed impermeable containersbearing appropriate labels. (See the hazard communicationsection elsewhere in this publication for label requirements.)

The competent person must examine employee worksuitsat least once per work shift for rips or tears. Rips or tearsfound while an employee is working must be mended or theworksuit replaced immediately.

What are the hygiene-related requirements

for employees performing Class I asbestos

work involving more than 25 linear feet or

10 square feet of thermal system insulation

or surfacing ACM or PACM?

For this class of asbestos work, the requirements are asfollows:

■ Employers must create a decontamination area adjacentto and connected with the regulated area.

■ Workers must enter and exit the regulated area throughthe decontamination area.

83

Page 85: Chemical Hazards in Construction

33

The decontamination area must include an equipmentroom, shower area, and clean room in series and complywith the following:

■ Equipment room must have impermeable, labeled bags andcontainers to store and dispose of contaminated protectiveequipment.

■ Shower area must be adjacent to both the equipment andclean rooms, unless work is performed outdoors or thisarrangement is not feasible (in either case, employers mustensure that employees remove asbestos contaminationfrom their worksuits in the equipment room using a HEPAvacuum before proceeding to a shower not adjacent to thework area or remove their contaminated worksuits in theequipment room, don clean worksuits, and proceed to ashower not adjacent to the work area).

■ Clean room must have a locker or appropriate storagecontainer for each employee.

Note: When it is not feasible to provide a change areaadjacent to the work area, or when the work is performedoutdoors, employees may clean protective clothing with aportable HEPA vacuum before leaving the regulated area.Employees then must shower and change into “streetclothing” in a clean change area meeting the requirementsdescribed above.

To enter the regulated area, employees must pass throughthe equipment room. But before entering the regulated area,employees must do the following:

■ Enter the decontamination area through the clean room.

■ Remove and deposit street clothing within a providedlocker.

■ Put on protective clothing and respiratory protection beforeleaving the clean area.

84

Page 86: Chemical Hazards in Construction

34

Before exiting the regulated area, employees must dothe following:

■ Remove all gross contamination and debris.

■ Remove protective clothing in the equipment room(depositing the clothing in labeled, impermeable bags orcontainers).

■ Remove respirators in the shower and then shower beforeentering the clean room to change into “street clothing.”

Note: When workers consume food or beverages at theClass I worksite, employers must provide lunch areas withairborne asbestos levels below the PEL and/or excursion limit.

What are the hygiene-related requirements

for employees performing other Class I

asbestos work and Class II and III asbestos

work where exposures exceed a PEL or

where a negative exposure assessment

has not been produced?

For this class of asbestos work, the requirements are asfollows:

■ Employers must establish an equipment room or areaadjacent to the regulated area for the decontamination ofemployees and their equipment.

■ Workers must cover area with an impermeable drop clothon the floor or horizontal work surface and must be largeenough to accommodate equipment cleaning and personalprotective equipment removal without spreadingcontamination beyond the area.

■ Workers must clean area with a HEPA vacuum beforeremoving work clothing.

85

Page 87: Chemical Hazards in Construction

35

■ Workers must clean all equipment and surfaces ofcontainers filled with ACM before removal.

■ Employers must ensure employees enter and exit theregulated area through the equipment room or area.

What are the hygiene-related requirements

for employees performing Class IV work?

For this class of asbestos work, the requirements areas follows:

■ Employers must ensure that workers cleaning up dust,waste, and debris while a Class I, II, or III activity is stillin progress observe the hygiene practices required of theworkers performing that activity.

■ Workers cleaning up asbestos-containing surfacing materialor thermal system insulation debris from a Class I or IIIactivity after the activity is finished must be provideddecontamination facilities required for Class I workinvolving less than 25 linear or 10 square feet of material,or for Class III work where exposure exceeds a PEL or nonegative exposure assessment exists.

Note: For any class of asbestos work, employers mustensure that workers do not smoke in any work area withasbestos exposure.

What are an employer’s

housekeeping responsibilities?

Asbestos waste, scrap, debris, bags, containers,equipment, and contaminated clothing consigned fordisposal must be collected and disposed of in sealed, labeled,impermeable bags or other closed, labeled impermeablecontainers. When vacuuming methods are selected, employeesmust use and empty HEPA-filtered vacuuming equipmentcarefully and in a way that will minimize asbestos reentryinto the workplace.

86

Page 88: Chemical Hazards in Construction

36

Unless the building/facility owner demonstrates that theflooring does not contain asbestos, all vinyl and asphaltflooring material must be maintained in accordance withthe following conditions:

■ Sanding flooring material is prohibited.

■ Employees stripping finishes must use wet methods andlow abrasion pads at speeds lower than 300 revolutionsper minute.

■ Burnishing or dry buffing may be done only on flooringwith enough finish that the pad cannot contact the flooringmaterial.

■ Employees must not dust, dry sweep, or vacuum without aHEPA filter in an area containing thermal system insulationor surfacing material or visibly deteriorated ACM.

■ Employees must promptly clean up the waste and debrisand accompanying dust, and dispose of it in leak-tight,labeled containers.

For a quick reference to the OSHA standard’s provisionsby work class, please see the following table.

87

Page 89: Chemical Hazards in Construction

37

Qu

ick R

efe

ren

ce o

f P

rov

isio

ns b

y W

ork

Cla

ss*

Cla

ss I

Cla

ss I

IC

lass

III

Cla

ss I

V

Def

initi

onR

emov

al o

f th

erm

al s

yste

mR

emov

al o

f m

ater

ial

othe

rM

aint

enan

ce a

nd r

epai

rH

ouse

keep

ing

and

cust

odia

lin

sula

tion

(TSI

) an

d su

rfac

ing

than

TSI

or

SM c

onta

inin

gop

erat

ions

dis

turb

ing

mat

eria

lcl

eanu

p of

dus

t, w

aste

, an

dm

ater

ial

(SM

) co

ntai

ning

> 1%

asb

esto

sco

ntai

ning

> 1

% a

sbes

tos

debr

is fr

om C

lass

I, I

I, or

> 1%

asb

esto

sII

I ac

tiviti

es

Reg

ulat

edR

equi

red

(war

ning

sig

nsR

equi

red

(war

ning

sig

nsR

equi

red

(war

ning

sig

nsR

equi

red

(war

ning

sig

nsA

reas

man

dato

ry)

man

dato

ry)

man

dato

ry)

man

dato

ry)

Com

pete

nt■

Mus

t be

ons

ite■

Mus

t be

ons

ite■

Mus

t be

ons

ite■

Mus

t be

ons

itePe

rson

■M

ust

insp

ect

each

wor

kshi

ft■

Mus

t in

spec

t of

ten

■M

ust

insp

ect

ofte

n■

Mus

t in

spec

t of

ten

■M

ust

atte

nd s

uper

viso

ry■

Mus

t at

tend

sup

ervi

sory

■M

ust

atte

nd o

pera

tiona

l■

Mus

t at

tend

ope

ratio

nal

trai

ning

trai

ning

and

mai

nten

ance

tra

inin

gan

d m

aint

enan

ce t

rain

ing

Air

■In

itial

if

no n

egat

ive

■In

itial

if

no N

EA■

Initi

al i

f no

NEA

■In

itial

if

no N

EAM

onito

ring

expo

sure

ass

essm

ent

(NEA

)■

Dai

ly u

nles

s po

sitiv

e pr

essu

re■

Peri

odic

to

accu

rate

ly■

Peri

odic

to

accu

rate

ly■

Dai

ly u

nles

s po

sitiv

e pr

essu

rem

ode

resp

irato

r is

used

pred

ict

if >

PELs

pred

ict

if >

PELs

mod

e re

spira

tor

is us

ed■

Add

ition

al i

f co

nditi

ons

■A

dditi

onal

if

cond

ition

s■

Add

ition

al i

f co

nditi

ons

■A

dditi

onal

if

cond

ition

s ch

ange

chan

gech

ange

chan

geN

ote:

Ter

min

ate

if <

perm

issib

leN

ote:

Te

rmin

ate

if <

PELs

Not

e:

Term

inat

e if

< PE

LsN

ote:

Te

rmin

ate

if <

PELs

expo

sure

lim

its (

PELs

)

*Thi

s is

an o

verv

iew

of

the

stan

dard

s’ re

quir

emen

ts.

You

mus

t co

nsul

t th

e st

anda

rd f

or t

he s

peci

fics

of t

he r

equi

rem

ents

for

eac

h cl

ass.

88

Page 90: Chemical Hazards in Construction

38

Qu

ick R

efe

ren

ce

of P

rov

isio

ns b

y W

ork

Cla

ss*

(continued)

Cla

ss I

Cla

ss I

IC

lass

III

Cla

ss I

V

Med

ical

Req

uire

d if

Req

uire

d if

Req

uire

d if

Req

uire

d if

Surv

eilla

nce

■W

eari

ng n

egat

ive-

■W

eari

ng n

egat

ive-

■W

eari

ng n

egat

ive-

■W

eari

ng n

egat

ive-

pres

sure

res

pira

tor,

orpr

essu

re r

espi

rato

r, or

pres

sure

res

pira

tor,

orpr

essu

re r

espi

rato

r, or

■>

30 d

ays

of w

ork/

year

■>

30 d

ays

of w

ork/

year

■>

30 d

ays

of w

ork/

year

■>

PEL

for

mor

e th

an30

day

s/ye

ar

Res

pira

tors

Man

dato

ry f

or a

ll C

lass

I j

obs

Man

dato

ry i

fM

anda

tory

if

Man

dato

ry■

Non

-inta

ct r

emov

al,

or■

No

NEA

, or

■In

reg

ulat

ed a

rea

whe

re■

No

NEA

, or

■T

SI o

r SM

dist

urbe

d, o

rre

quire

d, o

r■

> PE

L, o

r■

> PE

L, o

r■

If >

PEL,

or

■D

ry r

emov

al (

exce

pt f

or■

Dry

rem

oval

(ex

cept

for

■In

em

erge

ncie

sro

ofin

g),

orro

ofin

g),

or■

In e

mer

genc

ies

■In

em

erge

ncie

s

Prot

ectiv

eR

equi

red

for

all

jobs

if

Req

uire

d fo

r al

l jo

bs i

fR

equi

red

for

all

jobs

if

Req

uire

d fo

r al

l jo

bs i

fC

loth

ing

and

■>

25 li

near

or

10 s

quar

e■

No

NEA

, or

■N

o N

EA, o

r■

No

NEA

, or

Equi

pmen

t

feet

of T

SI o

r■

> PE

L■

> PE

L■

> PE

L■

SM r

emov

al,

or■

No

NEA

, or

■>

PEL

Tra

inin

gEq

uiva

lent

to

EPA

Mod

elEq

uiva

lent

to

MA

P co

urse

Equi

vale

nt t

o A

HER

AEq

uiva

lent

to

AH

ERA

Acc

redi

tatio

n Pl

an (

MA

P)if

criti

cal

barr

iers

req

uire

d;co

urse

for

mai

nten

ance

cour

se f

or m

aint

enan

ceas

best

os a

bate

men

t w

orke

rsot

herw

ise,

tra

in o

n sp

ecifi

can

d cu

stod

ial

staf

fan

d cu

stod

ial

staf

fco

urse

wor

k pr

actic

es a

nd e

ngin

eeri

ngco

ntro

ls th

at m

ust

be u

sed

*Thi

s is

an o

verv

iew

of

the

stan

dard

s’ re

quir

emen

ts.

You

mus

t co

nsul

t th

e st

anda

rd f

or t

he s

peci

fics

of t

he r

equi

rem

ents

for

eac

h cl

ass.

89

Page 91: Chemical Hazards in Construction

39

Qu

ick R

efe

ren

ce

of P

rov

isio

ns b

y W

ork

Cla

ss*

(continued)

Cla

ss I

Cla

ss I

IC

lass

III

Cla

ss I

V

Empl

oyee

Req

uire

d if

> 25

line

ar o

r 10

If >

PEL

or n

o N

EAIf

> PE

L or

no

NEA

If c

lean

ing

up a

sbes

tos

and

squa

re f

eet

TSI

or

SM r

emov

al■

Equi

pmen

t ro

om/a

rea

■Eq

uipm

ent

room

/are

aco

ntai

ning

sur

faci

ng m

ater

ial

orEq

uipm

ent

■Fu

ll de

con

unit

re

quire

d

requ

ired

ther

mal

sys

tem

ins

ulat

ion

debr

isD

econ

tam

i-■

Equi

pmen

t ro

om,

show

er,

and

■Im

perm

eabl

e dr

opcl

oths

■Im

perm

eabl

e dr

opcl

oths

from

a C

lass

I o

r III

act

ivity

natio

ncl

ean

room

in

serie

s co

nnec

ted

requ

ired

r

equi

red

afte

r th

e ac

tivity

is

finis

hed

to t

he r

egul

ated

are

a; o

ther

■A

rea

mus

t ac

com

mod

ate

■A

rea

mus

t ac

com

mod

ate

■Eq

uipm

ent

room

/are

ade

con

faci

lity

arra

ngem

ents

are

clea

nup

clea

nup

requ

ired

acce

ptab

le i

f th

e sp

ecifi

ed s

erie

s■

Mus

t cl

ean

wor

k cl

othe

s■

Mus

t cl

ean

wor

k cl

othe

s■

Dro

pclo

ths

requ

ired

arra

ngem

ent

is n

ot f

easi

ble

with

HEP

A v

acuu

m b

efor

ew

ith H

EPA

vac

uum

bef

ore

■A

rea

mus

t ac

com

mod

ate

(see

29

CFR

Par

t 19

26.1

101,

rem

oval

rem

oval

clea

nup

Subp

art

Z)

■M

ust

Dec

onta

min

ate

all

■M

ust

Dec

onta

min

ate

all

■M

ust

clea

n w

ork

clot

hes

■Lu

nch

area

sPP

EPP

Ew

ith H

EPA

vac

uum

bef

ore

■M

ust

ente

r re

gula

ted

area

■M

ust

ente

r re

gula

ted

area

rem

oval

thro

ugh

equi

pmen

t ro

om/

thro

ugh

equi

pmen

t ro

om/

■M

ust

deco

ntam

inat

e al

l PP

Ede

con

area

d

econ

are

a■

Mus

t en

ter

regu

late

d ar

ea■

Mus

t en

ter

regu

late

d ar

ea■

Mus

t en

ter

regu

late

d ar

eath

roug

h eq

uipm

ent

room

/th

roug

h eq

uipm

ent

room

/th

roug

h eq

uipm

ent

room

/de

con

area

deco

n ar

ea

dec

on a

rea

No

smok

ing

in w

ork

area

No

smok

ing

in w

ork

area

If N

EA m

ust

vacu

um

No

smok

ing

in w

ork

area

*Thi

s is

an o

verv

iew

of

the

stan

dard

s’ re

quir

emen

ts.

You

mus

t co

nsul

t th

e st

anda

rd f

or t

he s

peci

fics

of t

he r

equi

rem

ents

for

eac

h cl

ass.

Not

e:

If cl

eani

ng u

p du

st,

was

te,

and

debr

is w

hile

aC

lass

I,

II, o

r III

act

ivity

is

still

in p

rogr

ess,

the

req

uire

men

tsof

tha

t ac

tivity

app

ly.

Not

e:

Mus

t fo

llow

det

aile

dde

cont

amin

atio

n pr

oced

ures

(se

e29

CFR

Par

t 19

26.1

101(

j)(1)

(iii)

If <

25 li

near

or

10 s

quar

e fe

etT

SI o

r SM

rem

oval

■Eq

uipm

ent

room

/are

a re

quir

ed■

Impe

rmea

ble

drop

clot

hsre

quir

ed■

Are

a m

ust

acco

mm

odat

e cl

eanu

p■

Mus

t de

cont

amin

ate

all

pers

onal

prot

ectiv

e eq

uipm

ent

(PPE

)■

Mus

t en

ter

regu

late

d ar

ea t

hrou

gheq

uipm

ent

room

/dec

on a

rea

No

smok

ing

in w

ork

area

90

Page 92: Chemical Hazards in Construction

40

Qui

ck R

efer

ence

of P

rovi

sion

s by

Wor

k Cl

ass*

(continued)

Cla

ss I

Cla

ss I

IC

lass

III

Cla

ss I

V

Gen

eral

ly R

equi

red

■W

et m

etho

ds■

Wet

met

hods

■W

et m

etho

ds■

Wet

met

hods

Wor

k Pr

actic

es a

nd■

HEP

A v

acuu

m■

HEP

A v

acuu

m■

HEP

A v

acuu

m■

HEP

A v

acuu

mEn

gine

erin

g C

ontr

ols

■Pr

ompt

cle

anup

/dis

posa

l■

Prom

pt c

lean

up/d

ispo

sal

■Pr

ompt

cle

anup

/dis

posa

l■

Prom

pt c

lean

up/d

ispo

sal

Req

uire

d W

ork

■H

EPA

loc

al e

xhau

st■

HEP

A l

ocal

exh

aust

■H

EPA

loc

al e

xhau

st■

HEP

A l

ocal

exh

aust

Prac

tices

and

■En

clos

ure

or i

sola

tion

■En

clos

ure

■En

clos

ure

■En

clos

ure

Engi

neer

ing

Con

trol

s■

Dir

ecte

d ve

ntila

tion

■D

irec

ted

vent

ilatio

n■

Dir

ecte

d ve

ntila

tion

■D

irec

ted

vent

ilatio

nto

Com

ply

with

■O

ther

wor

k pr

actic

es■

Oth

er w

ork

prac

tices

■O

ther

wor

k pr

actic

es■

Oth

er w

ork

prac

tices

PEL

s■

Res

pira

tors

■R

espi

rato

rs■

Res

pira

tors

■R

espi

rato

rs

Proh

ibite

d W

ork

■H

igh-

spee

d ab

rasi

ve■

Hig

h-sp

eed

abra

sive

dis

c■

Hig

h-sp

eed

abra

sive

dis

c■

Hig

h-sp

eed

abra

sive

dis

cPr

actic

es a

nddi

sc s

aws

with

out

HEP

Asa

ws

with

out

HEP

Asa

ws

with

out

HEP

Asa

ws

with

out

HEP

AA

dmin

istr

ativ

e■

Com

pres

sed

air

with

out

■C

ompr

esse

d ai

r w

ithou

t■

Com

pres

sed

air

with

out

■C

ompr

esse

d ai

r w

ithou

tC

ontr

ols

capt

ure

devi

ceca

ptur

e de

vice

capt

ure

devi

ceca

ptur

e de

vice

■D

ry s

wee

ping

/sho

velin

g■

Dry

sw

eepi

ng/s

hove

ling

■D

ry s

wee

ping

/sho

velin

g■

Empl

oyee

rot

atio

n

Con

trol

s an

d■

Cri

tical

bar

rier

s/is

olat

ion

For

indo

or w

ork

only

■C

ritic

al b

arri

ers

requ

ired

See

Gen

eral

ly R

equi

red

Wor

k Pr

actic

esm

etho

ds r

equi

red

if■

Cri

tical

bar

rier

s/is

olat

ion

• If

no N

EAW

ork

Prac

tices

and

•>

25 li

near

or

10 s

quar

em

etho

ds r

equi

red

if•

> Pe

l vi

a m

onito

ring

Eng

inee

ring

Con

trol

sfe

et o

f T

SI o

r SM

rem

oval

•no

NEA

■Im

perm

eabl

e dr

opcl

oths

in t

his

tabl

e•

< 25

line

ar o

r 10

squ

are

•lik

ely

> a

PEL

requ

ired

feet

of

TSI

or

SM r

emov

al•

non-

inta

ct r

emov

al■

Loca

l H

EPA

exh

aust

only

if n

o N

EA o

r th

ere

■Im

perm

eabl

e dr

opcl

oths

requ

ired

are

adja

cent

wor

kers

requ

ired

■H

VA

C i

sola

tion

requ

ired

*Thi

s is

an o

verv

iew

of

the

stan

dard

s’ re

quir

emen

ts.

You

mus

t co

nsul

t th

e st

anda

rd f

or t

he s

peci

fics

of t

he r

equi

rem

ents

for

eac

h cl

ass.

91

Page 93: Chemical Hazards in Construction

41

Qu

ick R

efe

ren

ce

of P

rov

isio

ns b

y W

ork

Cla

ss*

(continued)

Cla

ss I

Cla

ss I

IC

lass

III

Cla

ss I

V

Con

trol

s an

d■

Impe

rmea

ble

drop

clot

hsFo

r re

mov

al o

f vi

nyl

and

Not

e:

Encl

osur

e or

iso

latio

nW

ork

Prac

tices

requ

ired

asph

alt

floor

ing

mat

eria

lsof

ope

ratio

n re

quire

d if

TSI

(continued)

■D

irec

ted

vent

ilatio

n re

quir

ed■

No

sand

ing

or S

M i

s dr

illed

, cu

t, ab

rade

d,if

no N

EA o

r >

a PE

L■

HEP

A v

acuu

msa

nded

, sa

wed

, or

chi

pped

■O

bjec

ts m

ust

be c

over

ed■

Wet

met

hods

■N

o dr

y sw

eepi

ngO

ne o

r m

ore

of t

he f

ollo

win

g■

Any

mec

hani

cal

chip

ping

mus

t be

cont

rols

mus

t be

use

d:do

ne i

n ne

gativ

e-pr

essu

re e

nclo

sure

■N

egat

ive-

pres

sure

enc

losu

re■

Inta

ct r

emov

al i

f po

ssib

le■

Glo

ve b

ag■

Dry

hea

t re

mov

al a

llow

ed■

Neg

ativ

e-pr

essu

re g

love

bag

■A

ssum

e co

ntai

ns a

sbes

tos

■N

egat

ive

pres

sure

glo

ve b

oxw

ithou

t an

ana

lysi

s■

Wat

er s

pray

pro

cess

■M

ini

encl

osur

eFo

r re

mov

al o

f ro

ofin

g m

ater

ials

■In

tact

rem

oval

if

poss

ible

■W

et m

etho

ds i

f fe

asib

le■

Cut

ting

mac

hine

mis

ting

■H

EPA

-vac

uum

deb

ris

■Lo

wer

to

grou

nd a

s so

on a

spo

ssib

le b

ut n

o la

ter

than

day

’s en

d■

Con

trol

dus

t of

unb

agge

d m

ater

ial

■Pr

even

t in

take

of

airb

orne

asb

esto

sth

roug

h ro

of v

ent

syst

em

*Thi

s is

an o

verv

iew

of

the

stan

dard

s’ re

quir

emen

ts.

You

mus

t co

nsul

t th

e st

anda

rd f

or t

he s

peci

fics

of t

he r

equi

rem

ents

for

eac

h cl

ass.

92

Page 94: Chemical Hazards in Construction

42

*Thi

s is

an o

verv

iew

of

the

stan

dard

s’ re

quir

emen

ts.

You

mus

t co

nsul

t th

e st

anda

rd f

or t

he s

peci

fics

of t

he r

equi

rem

ents

for

eac

h cl

ass.

Qui

ck R

efer

ence

of P

rovi

sion

s by

Wor

k Cl

ass*

(continued)

Cla

ss I

Cla

ss I

IC

lass

III

Cla

ss I

V

Con

trol

s an

dFo

r re

mov

al o

f ce

men

t-lik

e si

ding

,W

ork

Prac

tices

shin

gles

, or

tra

nsite

pan

els

(continued)

■In

tact

rem

oval

if

poss

ible

■W

et M

etho

ds■

Low

er t

o gr

ound

via

dus

t-tig

htch

ute,

cra

ne,

or h

oist

im

med

iate

lyor

pla

ce i

n an

im

perv

ious

was

teba

g or

wra

p in

pla

stic

she

etin

gan

d lo

wer

to

grou

nd b

y da

y’s

end

■C

ut n

ail

head

s

For

rem

oval

of

gask

ets

■U

se g

love

bag

s if

not

inta

ct■

Wet

rem

oval

■Pr

ompt

dis

posa

l■

Wet

scr

apin

g

Add

ition

al r

equi

rem

ents

■W

et m

etho

ds■

Inta

ct r

emov

al i

f po

ssib

le■

Cut

ting,

abr

adin

g, o

r br

eaki

ngpr

ohib

ited

93

Page 95: Chemical Hazards in Construction

The Hazards of Asphalt

Fumes

94

Page 96: Chemical Hazards in Construction

Common Name: ASPHALT FUMES

CAS Number: 8052-42-4DOT Number: NA 1999 (Asphalt)-----------------------------------------------------------------------------

HAZARD SUMMARY* Asphalt fumes can affect you when breathed in.* Asphalt fumes contain substances known to cause cancer.* Asphalt fumes can irritate the eyes on contact.* Breathing Asphalt fumes can irritate the nose, throat and

lungs causing coughing, wheezing and/or shortness ofbreath.

* Exposure to Asphalt fumes can cause severe irritation ofthe skin and may cause dermatitis and acne-like lesions.

* Breathing Asphalt fumes can cause headache, dizzinessand nausea.

* Long-term contact can cause skin pigment change which ismade worse by sunlight exposure.

* Cutback and Rapid Curing Liquid Asphalt are FLAM-MABLE and FIRE HAZARDS.

* Asphalt is derived from petroleum. Asphalt and Coal TarPitch are different. If you are actually working with CoalTar Pitch chemicals,

IDENTIFICATIONAsphalt is a blackish-brown mass. Asphalt fumes areproduced during the manufacture and heating of Asphalt,which is used for road building and roofing, and in rubber andadhesives.

REASON FOR CITATION* Asphalt fumes are on the Hazardous Substance List

because they are cited by ACGIH, DOT, NIOSH and NFPA.* Definitions are provided on page 5.

HOW TO DETERMINE IF YOU ARE BEINGEXPOSEDThe HAZCOM Standard requires most employers tolabel chemicals in the workplace and requires employersto provide their employees with information and trainingconcerning chemical hazards and controls.

RTK Substance number: 0170-----------------------------------------------------------------------------

* Exposure to hazardous substances should be routinelyevaluated. This may include collecting personal and area airsamples. You can obtain copies of sampling results fromyour employer. You have a legal right to this informationunder OSHA 1910.1020.

* If you think you are experiencing any work-related healthproblems, see a doctor trained to recognize occupationaldiseases. Take this Fact Sheet with you.

WORKPLACE EXPOSURE LIMITSNIOSH: The recommended airborne exposure limit is

5 mg/m3, which should not be exceeded at anytime.

ACGIH: The recommended airborne exposure limit is0.5 mg/m3 (as the inhalable fraction) averagedover an 8-hour workshift.

* Asphalt fumes contain substances known to causeCANCER in humans. There may be no safe level ofexposure to a carcinogen, so all contact should be reducedto the lowest possible level.

WAYS OF REDUCING EXPOSURE* Enclose operations and use local exhaust ventilation at the

site of chemical release. If local exhaust ventilation orenclosure is not used, respirators should be worn.

* Wear protective work clothing.* Wash thoroughly immediately after exposure to Asphalt

fumes and at the end of the workshift.* Post hazard and warning information in the work area. In

addition, as part of an ongoing education and trainingeffort, communicate all information on the health and safetyhazards of Asphalt fumes to potentially exposed workers.

95

Page 97: Chemical Hazards in Construction

ASPHALT FUMES

This Fact Sheet is a summary source of information of allpotential and most severe health hazards that may result fromexposure. Duration of exposure, concentration of thesubstance and other factors will affect your susceptibility toany of the potential effects described below.-----------------------------------------------------------------------------

HEALTH HAZARD INFORMATION

Acute Health EffectsThe following acute (short-term) health effects may occurimmediately or shortly after exposure to Asphalt fumes:

* Asphalt fumes can irritate the eyes on contact.* Breathing Asphalt fumes can irritate the nose, throat and

lungs causing coughing, wheezing and/or shortness ofbreath.

* Exposure to Asphalt fumes can cause severe irritation ofthe skin and may cause dermatitis and acne-like lesions.

* Breathing Asphalt fumes can cause headache, dizzinessand nausea.

Chronic Health EffectsThe following chronic (long-term) health effects can occur atsome time after exposure to Asphalt fumes and can last formonths or years:

Cancer Hazard* Asphalt fumes contain substances such as

Benzo(a)pyrene and Dibenz(a,h)anthracene that areknown to cause cancer in humans.

Reproductive Hazard* According to the information presently available

Asphalt fumes have not been tested for their ability toaffect reproduction.

Other Long-Term Effects* Long-term contact can cause skin pigment change which is

made worse by sunlight exposure.* Very irritating substances may affect the lungs. It is not

known whether Asphalt fumes cause lung damage.

MEDICAL

Medical TestingBefore beginning employment and at regular times after that,for those with frequent or potentially high exposures, thefollowing are recommended:

* Lung function tests.

Any evaluation should include a careful history of past andpresent symptoms with an exam. Medical tests that look fordamage already done are not a substitute for controllingexposure.

Request copies of your medical testing. You have a legal rightto this information under OSHA 1910.1020.

Mixed Exposures* Exposure to sunlight may make skin effects of Asphalt

fumes worse.* Because smoking can cause heart disease, as well as lung

cancer, emphysema, and other respiratory problems, it mayworsen respiratory conditions caused by chemicalexposure. Even if you have smoked for a long time,stopping now will reduce your risk of developing healthproblems.

WORKPLACE CONTROLS AND PRACTICES

Unless a less toxic chemical can be substituted for a hazardoussubstance, ENGINEERING CONTROLS are the most effectiveway of reducing exposure. The best protection is to encloseoperations and/or provide local exhaust ventilation at the siteof chemical release. Isolating operations can also reduceexposure. Using respirators or protective equipment is lesseffective than the controls mentioned above, but is sometimesnecessary.

In evaluating the controls present in your workplace, consider:(1) how hazardous the substance is, (2) how much of thesubstance is released into the workplace and (3) whetherharmful skin or eye contact could occur. Special controlsshould be in place for highly toxic chemicals or whensignificant skin, eye, or breathing exposures are possible.

In addition, the following controls are recommended:

* Where possible, automatically transfer Asphalt or pumpliquid Asphalt from drums or other storage containers toprocess containers.

* Before entering a confined space where Asphalt may bepresent, check to make sure that an explosive concentrationdoes not exist.

Good WORK PRACTICES can help to reduce hazardousexposures. The following work practices are recommended:

* Workers whose clothing has been contaminated byAsphalt should change into clean clothing promptly.

* Do not take contaminated work clothes home. Familymembers could be exposed.

* Contaminated work clothes should be laundered byindividuals who have been informed of the hazards ofexposure to Asphalt.

* Eye wash fountains should be provided in the immediatework area for emergency use.

* If there is the possibility of skin exposure, emergencyshower facilities should be provided.

* On skin contact with Asphalt, immediately wash or showerto remove the chemical. At the end of the workshift, washany areas of the body that may have contacted Asphalt,whether or not known skin contact has occurred.

96

Page 98: Chemical Hazards in Construction

ASPHALT FUMES

* Do not eat, smoke, or drink where Asphalt is handled,processed, or stored, since the chemical can be swallowed.Wash hands carefully before eating, drinking, smoking, orusing the toilet.

PERSONAL PROTECTIVE EQUIPMENT

WORKPLACE CONTROLS ARE BETTER THAN PERSONALPROTECTIVE EQUIPMENT. However, for some jobs (such asoutside work, confined space entry, jobs done only once in awhile, or jobs done while workplace controls are beinginstalled), personal protective equipment may be appropriate.

OSHA 1910.132 requires employers to determine theappropriate personal protective equipment for each hazard andto train employees on how and when to use protectiveequipment.

The following recommendations are only guidelines and maynot apply to every situation.

Clothing* Avoid skin contact with Asphalt. Wear protective gloves

and clothing. Safety equipment suppliers/manufacturerscan provide recommendations on the most protectiveglove/clothing material for your operation.

* All protective clothing (suits, gloves, footwear, headgear)should be clean, available each day, and put on beforework.

Eye Protection* Wear indirect-vent, impact and splash resistant goggles

when working with liquids or semi-solids.* Wear a face shield along with goggles when working with

corrosive, highly irritating or toxic substances.

Respiratory ProtectionIMPROPER USE OF RESPIRATORS IS DANGEROUS. Suchequipment should only be used if the employer has a writtenprogram that takes into account workplace conditions,requirements for worker training, respirator fit testing andmedical exams, as described in OSHA 1910.134.

* Where the potential exists for exposure over 0.5 mg/m3,use a MSHA/NIOSH approved supplied-air respirator witha full facepiece operated in a pressure-demand or otherpositive-pressure mode. For increased protection use incombination with an auxiliary self-contained breathingapparatus operated in a pressure-demand or other positive-pressure mode.

HANDLING AND STORAGE

* Prior to working with Asphalt you should be trained on itsproper handling and storage.

* Asphalt may ignite or explode when mixed with NAPHTHA,other VOLATILE SOLVENTS, and LIQUID OXYGEN.

* Asphalt is not compatible with OXIDIZING AGENTS (suchas PERCHLORATES, PEROXIDES, PERMAN-GANATES,CHLORATES, NITRATES, CHLORINE, BROMINE andFLUORINE).

* Store in tightly closed containers in a cool, well-ventilatedarea.

* Sources of ignition, such as smoking and open flames, areprohibited where Cutback and Rapid Curing Asphalt areused, handled, or stored.

* Metal containers involving the transfer of Cutback andRapid Curing Asphalt should be grounded and bonded.

* Wherever lighter or liquid forms of Asphalt are used,handled, manufactured, or stored, use explosion-proofelectrical equipment and fittings.

QUESTIONS AND ANSWERS

Q: If I have acute health effects, will I later get chronic healtheffects?

A: Not always. Most chronic (long-term) effects result fromrepeated exposures to a chemical.

Q: Can I get long-term effects without ever having short-term effects?

A: Yes, because long-term effects can occur from repeatedexposures to a chemical at levels not high enough tomake you immediately sick.

Q: What are my chances of getting sick when I have beenexposed to chemicals?

A: The likelihood of becoming sick from chemicals isincreased as the amount of exposure increases. This isdetermined by the length of time and the amount ofmaterial to which someone is exposed.

Q: When are higher exposures more likely?A: Conditions which increase risk of exposure include

physical and mechanical processes (heating, pouring,spraying, spills and evaporation from large surface areassuch as open containers), and "confined space"exposures (working inside vats, reactors, boilers, smallrooms, etc.).

Q: Is the risk of getting sick higher for workers than forcommunity residents?

A: Yes. Exposures in the community, except possibly incases of fires or spills, are usually much lower than thosefound in the workplace. However, people in thecommunity may be exposed to contaminated water as wellas to chemicals in the air over long periods. This may bea problem for children or people who are already ill.

Q: Don't all chemicals cause cancer?A: No. Most chemicals tested by scientists are not cancer-

causing.97

Page 99: Chemical Hazards in Construction

ASPHALT FUMES

DEFINITIONS

ACGIH is the American Conference of Governmental IndustrialHygienists. It recommends upper limits (called TLVs) forexposure to workplace chemicals.

A carcinogen is a substance that causes cancer.

The CAS number is assigned by the Chemical AbstractsService to identify a specific chemical.

A combustible substance is a solid, liquid or gas that will burn.

A corrosive substance is a gas, liquid or solid that causesirreversible damage to human tissue or containers..

DOT is the Department of Transportation, the federal agencythat regulates the transportation of chemicals.

EPA is the Environmental Protection Agency, the federalagency responsible for regulating environmental hazards.

A fetus is an unborn human or animal.

A flammable substance is a solid, liquid, vapor or gas that willignite easily and burn rapidly.

The flash point is the temperature at which a liquid or solidgives off vapor that can form a flammable mixture with air.

HHAG is the Human Health Assessment Group of the federalEPA.

IARC is the International Agency for Research on Cancer, ascientific group that classifies chemicals according to theircancer-causing potential.

A miscible substance is a liquid or gas that will evenlydissolve in another.

mg/m3 means milligrams of a chemical in a cubic meter of air. Itis a measure of concentration (weight/volume).

MSHA is the Mine Safety and Health Administration, thefederal agency that regulates mining. It also evaluates andapproves respirators.

A mutagen is a substance that causes mutations. A mutationis a change in the genetic material in a body cell. Mutationscan lead to birth defects, miscarriages, or cancer.

NAERG is the North American Emergency ResponseGuidebook. It was jointly developed by Transport Canada, theUnited States Department of Transportation and the Secretariatof Communications and Transportation of Mexico. It is a guidefor first responders to quickly identify the specific or generichazards of material involved in a transportation incident, and toprotect themselves and the general public during the initialresponse phase of the incident.

NCI is the National Cancer Institute, a federal agency thatdetermines the cancer-causing potential of chemicals.

NFPA is the National Fire Protection Association. It classifiessubstances according to their fire and explosion hazard.

NIOSH is the National Institute for Occupational Safety andHealth. It tests equipment, evaluates and approves respirators,conducts studies of workplace hazards, and proposesstandards to OSHA.

NTP is the National Toxicology Program which tests chemicalsand reviews evidence for cancer.

OSHA is the Occupational Safety and Health Administration,which adopts and enforces health and safety standards.

PIH is a DOT designation for chemicals which are PoisonInhalation Hazards.

ppm means parts of a substance per million parts of air. It is ameasure of concentration by volume in air.

A reactive substance is a solid, liquid or gas that releasesenergy under certain conditions.

A teratogen is a substance that causes birth defects bydamaging the fetus.

TLV is the Threshold Limit Value, the workplace exposure limitrecommended by ACGIH.

The vapor pressure is a measure of how readily a liquid or asolid mixes with air at its surface. A higher vapor pressureindicates a higher concentration of the substance in air andtherefore increases the likelihood of breathing it in.

98

Page 100: Chemical Hazards in Construction

>>>>>>>>>>>>>>>>> E M E R G E N C Y I N F O R M A T I O N <<<<<<<<<<<<<<<<<

Common Name: ASPHALT FUMESDOT Number: NA 1999 (Asphalt)NAERG Code: 130CAS Number: 8052-42-4

Hazard rating NJDHSS NFPAFLAMMABILITY - 1, 2 or 3

REACTIVITY - 0FLAMMABLE OR COMBUSTIBLE DEPENDING ON

CONSISTENCYPOISONOUS GASES ARE PRODUCED IN FIRECONTAINERS MAY EXPLODE IN FIRE

Hazard Rating Key: 0=minimal; 1=slight; 2=moderate;3=serious; 4=severe

FIRE HAZARDS

* Cutback and Rapid Curing Asphalt are FLAMMABLE.* Typical or Medium to Slow Curing Asphalt liquids are

COMBUSTIBLE.* Use dry chemical, CO2, water spray, or foam extinguishers.* POISONOUS GASES ARE PRODUCED IN FIRE.* CONTAINERS MAY EXPLODE IN FIRE.* Use water spray to keep fire-exposed containers cool.* Vapors may travel to a source of ignition and flash back.* If employees are expected to fight fires, they must be trained

and equipped as stated in OSHA 1910.156.

SPILLS AND EMERGENCIES

If Asphalt is spilled or leaked, take the following steps:

* Evacuate persons not wearing protective equipment fromarea of spill or leak until clean-up is complete.

* Remove all ignition sources.* Cover with dry lime, sand or soda ash, and place in covered

containers for disposal.* Ventilate and wash area after clean-up is complete.* Keep Asphalt out of a confined space, such as a sewer,

because of the possibility of an explosion, unless the seweris designed to prevent the build-up of explosiveconcentrations.

* It may be necessary to contain and dispose of Asphalt as aHAZARDOUS WASTE. Contact your state Department ofEnvironmental Protection (DEP) or your regional office of thefederal Environmental Protection Agency (EPA) for specificrecommendations.

* If employees are required to clean-up spills, they must beproperly trained and equipped. OSHA 1910.120(q) may beapplicable.

==============================================FOR LARGE SPILLS AND FIRES immediately call your firedepartment. You can request emergency information from thefollowing:

CHEMTREC: (800) 424-9300NJDEP HOTLINE: 1-877-WARN-DEP==============================================

HANDLING AND STORAGE (See page 3)

FIRST AID

Eye Contact* Immediately flush with large amounts of water. Continue

without stopping for at least 30 minutes, occasionally liftingupper and lower lids. Seek medical attention immediately.

Skin Contact* Remove contaminated clothing. Wash contaminated skin

with soap and water.

Breathing* Remove the person from exposure.* Begin rescue breathing (using universal precautions) if

breathing has stopped and CPR if heart action has stopped.* Transfer promptly to a medical facility.

PHYSICAL DATA

Flash Point:Cutback Asphalt: less than 50oF (10oC)Slow to Rapid Curing Asphalt: 80oF (27oC) to 225oF (107oC)Typical Asphalt: 400oF (204oC)Water Solubility: Insoluble

OTHER COMMONLY USED NAMES

Chemical Name:Asphalt fumesOther Names:Road Tar; Mineral Pitch; Petroleum Pitch; Bitumen

99

Page 101: Chemical Hazards in Construction

Lead Hazards in Construction

100

Page 102: Chemical Hazards in Construction

101

Page 103: Chemical Hazards in Construction

102

Page 104: Chemical Hazards in Construction

103

Page 105: Chemical Hazards in Construction

104

Page 106: Chemical Hazards in Construction

105

Page 107: Chemical Hazards in Construction

106

Page 108: Chemical Hazards in Construction

107

Page 109: Chemical Hazards in Construction

108

Page 110: Chemical Hazards in Construction

109

Page 111: Chemical Hazards in Construction

110

Page 112: Chemical Hazards in Construction

111

Page 113: Chemical Hazards in Construction

112

Page 114: Chemical Hazards in Construction

113

Page 115: Chemical Hazards in Construction

114

Page 116: Chemical Hazards in Construction

115

Page 117: Chemical Hazards in Construction

116

Page 118: Chemical Hazards in Construction

117

Page 119: Chemical Hazards in Construction

118

Page 120: Chemical Hazards in Construction

119

Page 121: Chemical Hazards in Construction

Methylene

Chloride in the Construction

Industry

120

Page 122: Chemical Hazards in Construction

Background When established under the authority of the Occupational Safety and Health Act of I970, the Occupational Safety and Health Administration (OSHA) had 2 years to adopt existing federal standards or national consensus standards1 so it would have Standards in place to enforce. OSHA chose to adopt existing federal standards issued under the Walsh-Healey Public Contracts Act, which were derived from threshold limit values of the American Conference of Governmental Industrial Hygienists and consensus standards from standards developing organizations such as the American National Standards Institute (ANSI).

For methylene chloride, OSHA adopted an ANSI standard under Subpart Z of Title 29 Code of Federal Regulations (CFR ), Part 1910.1000 to ensure that employee exposure did not exceed 500 parts per million parts of air (500 ppm) as an 8-hour time-weighted average (TWA}---i.e., the average exposure during an 8-hour period. Since 1971, however, industrial experience, new developments in technology, and emerging scientific data clearly indicate that this limit did not adequately protect worker health. The agency realized the need to better control worker exposure to methylene chloride due to its harmful health effects. Methylene chloride, also called dichloromethane, is a volatile, colorless liquid with a chloroformlike odor. Inhalation and skin exposure are the predominant means of exposure to methylene chloride. Inhaling the vapor causes mental confusion, light-headedness, nausea, vomiting, and headache. With acute, or short term exposure, methylene chloride acts as an anesthetic; continued exposure may cause staggering, unconsciousness, and even death. High concentrations of the vapors may cause irritation of the eyes and respiratory tract and aggravate the symptoms of angina. Sin contact with liquid methylene chloride causes irritation and burns. Splashing methylene chloride into the eyes causes irritation. Studies on laboratory animals indicate that long-term (chronic)exposure causes cancer.

Methylene chloride is used in various industrial processes in many different industries: paint stripping, pharmaceutical manufacturing, paint remover manufacturing, metal cleaning and degreasing, adhesives manufacturing and use, polyurethane foam production, film base manufacturing, polycarbonate resin production, and

1Consensus standards are developed by private, standards-developing organizations and are discussed and substantially agreed upon through consensus by industry, labor, and other representatives.

121

Page 123: Chemical Hazards in Construction

distribution and formulation of solvents. The agency adopted the methylene chloride final rule on January 10, 1997 as published in the Federal Register. The rule becomes effective on April 10,1997. Scope and Application OSHA standard (Title 29 Code of Federal Regulations, Parts 1910.1052, 1915.1052, and 1926.1152) covers all occupational exposures to methylene chloride in all workplaces in general industry, shipyard employment, and construction. Provisions of the Standard Exposure Limits The employer must ensure that no employee is exposed to an airborne concentration of methylene chloride in excess of 25 ppm as an 8-hour TWA. Reaching or exceeding the action level signals that employers must begin compliance activities such as exposure monitoring and medical surveillance. The action level for a concentration of airborne methylene chloride is 12.5 ppm calculated as an 8-hour TWA. Reaching or exceeding the action level signals that employers must begin compliance activities such as exposure monitoring and medical surveillance. Regulated Areas The standard requires that the employer establish a regulated area where exposure to airborne concentrations of methylene chloride exceeds or can be expected to exceed either the PEL or the STEL. Only authorized employees2 may enter a regulated area. Employers must demarcate regulated areas to effectively alert employees of the boundaries and minimize the number of authorized employees exposed. Employers at multi-employer worksites must notify other employers onsite of the locations of all regulated areas and access restrictions. For each person entering a regulated area, the employer must supply appropriate respiratory protection. (See the respirator selection and use requirements elsewhere in this publication.) In addition, the employer must ensure that employees wearing regulators do not engage in activities,

2An authorized employee is any person specifically permitted by the employer or required by work duties to be present.

122

Page 124: Chemical Hazards in Construction

such as taking medication or chewing gum, that may interfere with respirator seal or performance.

The standard prohibits non-work activities -such as eating, drinking, smoking, chewing gum or tobacco, taking medication, or applying cosmetics-in regulated areas. Employees must not store any products associated with these activities in a regulated area. Hazard Communication

Provisions in the methylene chloride standard are consistent with those in OSHA’s Hazard Communication Standard---29 CFR 1910.1200, 29 CFR 1915.1200, and 29 CFR 1926.59---which require employers to inform employees of the hazards and identities of chemicals that they are exposed to when working. Specifically, the methylene chloride rule requires the employer to communicate on labels and in material safety data sheets (MSDSs) the health hazards of working with methylene chloride, including cancer, cardiac effects (including the elevation of carboxyhemoglobin), central nervous system effects, and skin and eye irritation. Exposure Monitoring

Through air sampling and monitoring, employers can better determine methylene chloride exposure, identify the source, and select the proper control methods-resulting in better protection for employees. Exposure monitoring also is key to determining which other requirements of the standard need to be met. To determine employees exposure to methylene chloride, the employer must use breathing zone air samples representative of the employees' 8-hour TWA and 15-minute exposure. To determine how employee exposures relate to the 8-hour TWA PEL, employers must take one or more personal breathing zone air sample representing full- shift exposure for each shift for at least one employee in each job classification in each work area. To determine how employee exposure relate to the STEL, employers must take one or more samples representing 15-minute exposures associated with those operations for each shift for at least one employee in each job classification in each work area. When the employer can document comparable exposure levels for similar operations in different work shifts, the employer only needs to determine representative employee exposures for the one shift where the highest exposure is expected.

123

Page 125: Chemical Hazards in Construction

Initial Monitoring All employers must monitor employee exposure initially to accurately determine

the airborne concentrations of methylene chloride. However, initial monitoring can be waived • if objective data---representing the highest methylene chloride exposure likely to

occur during processing using, or handling---demonstrate that methylene chloride cannot be released in airborne concentrations above the action level or the STEL,

• if the employer monitored employee airborne exposure within 1 year prior to the effective date of the standard and the monitoring satisfies all other requirements, or

• where employees are exposed to methylene chloride for fewer than 30 days per year (e.g., on a construction site) and the employer uses direct-reading instruments giving immediate results (such as a detector tube) and providing sufficient infor-mation to determine what control measures are necessary to reduce exposure to acceptable levels.

Employers with fewer than 20 employees must complete all initial monitoring within 300 days after the effective date of the standard, or by February 4, 1998, or after introduction of methylene chloride into the workplace; polyurethane foam manufacturers with 20 to 99 employees-within 210 days, or by November 6, 1997; and all other employers---within 120 days, or by, August 8,1997. Periodic Monitoring

The employer must begin an exposure monitoring program for all tasks where initial monitoring shows employee- exposures are above the action level or STEL.(See Table 1 for monitoring requirements in the standard.)

If employee exposure is above the action level, but at or below both the PEL and STEL, employers must monitor employees at least every 6 months. If exposure is above the PEL or STEL, employers must monitor employees at least every 3 months.

For employees with two consecutive measurements taken at least 7 days apart that indicate that exposure has decreased below both the PEL and STEL, employers may change the monitoring schedule from every 3 months to every 6 months. When periodic monitoring taken two consecutive times at least 7 days apart shows employee exposure is below the action level and the STEL, employers may discontinue

124

Page 126: Chemical Hazards in Construction

monitoring for those employees represented by the monitoring data.

Employers must perform additional monitoring when workplace conditions change---for example, when there is an indication that employee exposures have increased; changes occur in the production, process, control equipment, or work practices that could affect exposure levels; and leaks, ruptures, or other breakdowns occur.3

Table 1: Monitoring Requirements

Exposure Scenario Required Monitoring Activity Below the action level and at or below the STEL Below the action level and monitoring; above the STEL At or above the action level, at or below the PEL, and at or below the STEL At or above the action level, at or below the PEL, and above the STEL

Above the PEL and at or below the STEL Above the PEL and above the STEL

No 8-hour TWA or STEL monitoring required No 8-hour TWA monitoring required; monitor STEL exposures every 3 months. Monitor 8-hour TWA expo-sures every 6 months Monitor 8-hour TWA expo-sures every 6 months and monitor STEL exposures every 3 months. Monitor 8-hour exposures every 3 months. Monitor 8-hour TWA expo-sures and STEL exposures every 3 months.

3Cleanup of methylene chloride spills and repairs to leaks must be mace prior to performing exposure monitoring.

125

Page 127: Chemical Hazards in Construction

Employers must notify employees of all monitoring results, in writing, either individually or by posting the results in an accessible location, within 15 working days after receipt. When monitoring results show exposures above the PEL or STEL, the notification also must describe the corrective action being taken to reduce exposures to or below these limits.

Employers must allow affected employees or their designated representatives to observe any monitoring. The employer also must provide employees with appropriate protective clothing or equipment needed to enter regulated areas where the monitoring is performed. Employees and their designated representatives must wear the protective clothing and equipment provided and must comply with all other applicable safety and health procedures. Medical Surveillance

Medical surveillance is a comprehensive way to determine if exposure to workplace hazards adversely affects employee health. Through frequent required medical exams or tests, early detection of occupational diseases is possible and preventive measures can be taken to curtail overexposure.

Employers must put in place a medical surveillance program for all employees exposed to methylene chloride, unless the affected employees will be exposed to methylene chloride at or above the action level for fewer than 30 days per year or that affected employees will be exposed at, or above the PEL or STEL for fewer than 10 days during the year. Employers also must provide medical surveillance to any employee exposed above the PEL or STEL who has been identified by a physician or other licensed health care professional as at risk for cardiac disease or some other serious methylene chloride-related health condition and who requests inclusion, regardless of the duration of methylene chloride exposure; and to all employees during an emergency.

Employers must provide medical surveillance at no cost to the employee, without loss of pay, and at a reasonable time and place. Medical surveillance must be available • within 180 days of the effective date of the standard, or by October 7, 1997, or

before initial work assignment, whichever is most recent, unless adequate records show an affected employee has received appropriate medical surveillance within the past I2 months for employers with 20 or more employees,

• within 1 year of the effective date of the standard, or by April 10,1998, for employers with fewer than 20 employees,

126

Page 128: Chemical Hazards in Construction

• within 270 days of the effective date of the standard, or by January 5,1998, for foam manufacturers with 20 to 99 employees,

• within 1 year of any initial or subsequent mechanical surveillance. The frequency of required periodic medical exams varies by age of the employee,4

• at the end of employment or reassignment to an area where methylene chloride exposure is consistently below the action level and STEL, and/or

• when recommended in the physician's or licensed health care professional's5 written opinion.

For employees working in an atmosphere with methylene chloride concentrations above the PEL or STEL---and therefore required to use a respirator---the examining, physician or licensed health care professional must determine the employee's ability to wear an air-supplied respirator in negative-pressure mode or a gas mask with organic vapor canister for emergency escape and state this in a written opinion to both the employee and employer. A physician or licensed health care professional must supervise all medical procedures. Medical exams6 must include at least

• a comprehensive medical and work history,7 • a physical exam with special emphasis on the lungs, cardiovascular system, liver,

nervous system and skin, including blood pressure and pulse, • laboratory surveillance8 based on the employee's observed health status and

medical and work history, and 4Periodic medical exams are required as follows: employees 45 years or older---within 12 months of initial or subsequent medical surveillance; employees younger than 45 years---within 36 months of initial or subsequent medical surveillance (unless warranted sooner by a licensed health care professional, based on employee's annual medical and work history.)

5A person whose legally-permitted scope of practice allows him or her to independently perform the required health care surveillance activities. 6Medical surveillance---such as referrals for consultation or examination---may be provided.

7See Appendix B for an example of the medical and work history format that satisfy this requirement.

8See Appendix B for an example of the methylene chloride standard for medical test recommendations.

127

Page 129: Chemical Hazards in Construction

• any other information,9 the examining physician or licensed health care professional determines necessary to provide an appropriate assessment.

Employers, must ensure medical emergency exams are available in emergency situations and include, at a minimum,

• the appropriate medical treatment and decontamination of the exposed employee,

• a comprehensive physical exam with special emphasis on the nervous system, cardiovascular system, lungs, liver, and skin including blood pressure and pulse,

• an updated medical history as appropriate for the employee's medical condition and

• laboratory surveillance as indicated by the employee's health status. The employer must provide the examining physician or health care processional or any specialist involved in the diagnosis of methylene chloride-induced health effects with

• a copy of the methylene chloride standard and its appendices, • a description of the affected employee's past, current, and anticipated future

duties relating to methylene chloride exposure, • the employee's former or current methylene chloride exposure levels or

anticipated levels, their frequency, and anticipated exposure levels associated with emergencies,

• a description of any personal protective equipment (i.e., respirators) used or to be used, and

• information from previous employment-related medical surveillance. The physician or other licensed health care professional must give the employer and affected employee the written opinion regarding exam results within 15 days of completing the evaluation of the medical and lab findings, but no more than 30 days after

9When the examining physician or other licensed health care professional deems it necessary, the scope of the medical exam may be expanded and the appropriate additional medical surveillance provided.

128

Page 130: Chemical Hazards in Construction

the exam. The written medical opinion must be limited to

• the physician or licensed health care professional’s opinion whether the

employee has any detected medical conditions that would increase the risk of material, impairment from exposure to methylene chloride,

• any recommended limitations on employee exposure to methylene chloride and on the use of personal protective clothing or equipment and respirator,

• a statement that the physician or licensed, health care professional has informed the employee that ethylene chloride is a potential occupational carcinogen, of the risk factors for heart disease, and the potential exacerbation of underlying heart disease from methylene chloride exposure and its metabolism to carbon monoxide, and

• a statement that the physician or licensed health care professional has informed the employee of medical exam results and any medical conditions resulting from methylene chloride exposure requiring further explanation or treatment.

The examining physician or licensed health care professional must not reveal to the employer, orally or in writing, any specific records, findings, or diagnoses that have no bearing on occupational exposures to methylene chloride.

Methods of Compliance Control Measures Engineering and work practice controls are the primary methods used to reduce occupational exposure to methylene chloride. Employers must use engineering controls and work practices to effectively reduce and maintain employee exposure to methylene chloride at or below the PEL---except when the employer can prove these controls infeasible. Engineering Controls Engineering controls reduce employee exposure in the workplace either removing or isolating the hazard or isolating the worker from. Engineering controls reduce or remove ambient air contaminant exposure hazards. Local exhaust ventilation, general and special isolation devices or enclosures are examples of engineering controls.

129

Page 131: Chemical Hazards in Construction

Employers must institute and maintain the effectiveness of engineering controls to reduce employee exposure to or below the PEL. It is important to note that when engineering controls alone do not reduce methylene chloride exposure to or below the PEL and STEL, employers must reduce exposure to the lowest possible levels achievable and supplement them with the use of respirators. All other employers must implement the required engineering controls within l year after the effective date of the standard, or by April 10 1998. Employers with fewer than 20 employees are given 3 years to implement the required engineering controls and foam manufacturers with 20 to 99 employees have 2 years to implement the engineering control. Work Practice Controls Work practice controls reduce the likelihood of exposure by altering the manner in which a task is performed. An example would be to provide washing facilities and ensure that employees use them to prevent further methylene chloride exposure after leaving the work area.. Another safe practice is to require employees to eat, drink, smoke, take medication, or apply cosmetics outside of the methylene chloride work area. Administrative Controls

An administrative control removes the worker from exposure. For example, one method of controlling worker exposure to contaminants is by scheduling operations with the highest when the fewest employees are present. Employee rotation---i.e., scheduling several employees to perform work in the exposure area for shorter time limits---however, is not an effective means to control methylene chloride exposure since it may reduce individual exposure but increase the number of employees exposed. Employee rotation as a means of compliance with the PELs is strictly prohibited by this standard.

Under the methylene chloride rule, the employer must implement procedures to detect methylene chloride leaks. In work areas where spills may occur, provisions must be in place to contain them, promptly clean up, and safely dispose of any methylene

130

Page 132: Chemical Hazards in Construction

chloride contaminated waste materials. All leaks must be repaired and spills cleaned by employees wearing the appropriate personal protective equipment and who are trained in proper cleanup methods.10

Employers covered by this standard also may be covered by the provisions of 29 CFR 1910.120(q), Emergency Response to Hazardous Substance Releases. Respiratory Protection Unlike engineering and work practice controls, which reduce the hazard and result in a more "universal" protection, respirators protect employees individually. The sole use of engineer in a and work practice controls may not be enough to reduce occupational exposure below the PEL. In these cases, the combinations of engineering and work practice controls and respirators provide appropriate protection for all employees where methylene chloride is used. The employer must provide, at no cost to each affected employee, and ensure the use of respirators when

• an employee’s exposure to methylene chloride is likely to exceed the PEL and STEL,

• installing or implementing feasible engineering and work practice controls, • the employer demonstrates that engineering and work practices controls are

infeasible, such as some maintenance operations and repair activities, • feasible engineering controls and work practices do not sufficiently reduce

exposures to or below the PEL, and • in emergencies.

Appropriate respiratory protection varies with exposure levels, as specified in Table 2. Atmosphere-supplying respirators must be selected from those approved by the National Institute for Occupational Safety and Health (NIOSH). Employers may provide gas masks with organic vapor canisters, approved by NIOSH, only for use in emergency escape. the canisters, however, must be replaced after each use prior to returning the respirator to service. Where respirators are used, the employer must institute a comprehensive respiratory protection program that complies with 29 CFR 1910.134, Respiratory Protection

10See Appendix A in the methylene chloride standard for examples of procedures, satisfying this requirement.

131

Page 133: Chemical Hazards in Construction

Table 2: Minimum Requirements for Respiratory Protection for Airborne Methylene Chloride

Methylene Chloride Airborne Concentration (ppm) or Condition of Use

Minimum Respirator Required*

Up to 625 ppm (25 X PEL) (1)Continuous flow supplied-air respirator, hood, or helmet.

Up to 1250 ppm (50 X PEL) (1)Full facepiece supplied-air respirator operated in negative pressure (demand) mode. (2)Full facepiece self-contained breathing apparatus (SCBA) operated in negative pressure (demand) mode.

Up to 5000 ppm (200 X PEL) (1)Continuous flow supplied-air respirator, full facepiece (2)Pressure demand supplied-air respirator, full facepiece. (3)Positive pressure full facepiece SCBA.

Unknown Concentration, or above 5000 ppm (Greater than 200 X PEL)

(1)Positive pressure full facepiece SCBA. (2)Full facepiece pressure demand supplied-air respirator with an auxiliary self-contained air supply.

Firefighting Positive pressure full facepiece SCBA

Emergency Escape (1)Any continuous flow or pressure demand SCBA. (2)Gas mask with organic vapor canister.

*Respirators assigned for higher airborne concentrations may be used at the lower concentrations.

132

Page 134: Chemical Hazards in Construction

Each respirator issued must be fitted properly for the least possible facepiece leakage. For negative-pressure respirators used during emergencies, the employer must perform either qualitative or quantitative fit tests at the initial fitting and at least annually thereafter. The employer must allow employees wearing respirators to leave tie regulated area to readjust them for proper fit and to wash their faces and respirator facepieces as necessary. Hygiene Facilities and Practices

If through splashes, spills, or improper work practices employ ees can have skin contact with solutions containing 0. 1 percent or more methylene chloride, the employer must provide conveniently located washing facilities and ensure their use. Similarly, where there is potential for eye contact with solutions containing 0.1 percent or more methylene chloride, the employer must provide eyewash facilities within the immediate work area for emergency use. and ensure their use when necessary. Protective Work Clothing and Equipment

Employees must use personal protective clothing and equipment where needed to prevent methylene chloride-induced skin or eye irritation. The employer must provide the methylene chloride resistant clothing and equipment at no cost to the employees and ensure its use. The employer must clean, launder, repair, replace, and properly dispose of the protective clothing and equipment to keep it effective. Recordkeeping

The employer must establish and keep accurate records for all objective data, exposure monitoring, and medical surveillance, in accordance with Access to Employee Exposure and Medical Records, 29 CFR 1910.1020.

All records must be available for examining and copying by affected employees, former employees, designated employee representatives, and, following written requests, the Assistant Secretary of OSHA and the Director of NIOSH.

133

Page 135: Chemical Hazards in Construction

Objective Data Records If an employer relies on objective data to show that initial monitoring is unnecessary, the record supporting that exemption must include information on

• the methylene chloride-containing material in question, • the source of the objective data, • the testing protocol, results, and/or analysis of the material • a description of the exempted operation and the reasons why the data support

that exemption, and • other data relevant to the operations, materials, processing, or employee

exposure coverage by the exemption. The employer must maintain this record for as long as he/she relies on the

objective data. Exposure Measurement Records Employers with 20 or more employees must keep records of employee exposure measurements, for at least 3 years. These records must include

• the date of measurement for each sample taken, • the monitored operation involving methylene chloride exposure, • the sampling and analytical methods used and evidence of their accuracy. • the number, duration, and results of samples taken; • the type of personal protective equipment (i.e., respirators) worn, and • the name, social security number, job classification, and exposure monitoring

data for all represented employees, indicating which employees were actually monitored.

Employers with fewer than 20 employees must keep records of employee exposure measurements for at least 30 years. These records must include

• the date of measurement for each sample, • the number, duration, and results of samples taken, and • the name, social security number, job classification, and exposure monitoring

data for all represented employees, indicating which employees were actually monitored.

134

Page 136: Chemical Hazards in Construction

Medical Surveillance Records The employer must keep medical surveillance records for the duration of each

affected employees employment plus, 30 years. These records must include

• the name and social security number of each affected employee and a description of duties,

• physician or other licensed health care professionals' written opinions, and • employee medical conditions related to methylene chloride exposure.

Employee Information and Training The employer must provide information and training to all employees potentially exposed to methylene chloride prior to or when initially assigned to a job.

In addition to information required under OSHA's Hazard Communication Standard---29 CFR 1910.1200,1915.1200, and 1926.59---employers inform and train employees in an understandable way of the following:

• standard requirements, information available in the standard's appendices, and how to access a copy of it in the workplace, and

• the quantity, location, manner of use, release, and storage of methylene chloride and the specific nature of operations that could result in methylene chloride exposure, especially for exposures above the PEL or STEL-when employees" exposure to methylene chloride exceeds or can be expected to exceed the action level.

The employer must retrain employees as needed to ensure that each employee exposed at or above the action level or STEL maintains a good understanding of the principles of safe use and handling of methylene chloride in the workplace.

Also, when workplace procedures change or are added---such as task modifications---that increase employee exposures that exceed or can be expected to exceed the action level, the employer must update training to ensure continued understanding of methylene chloride hazards and control measures. Employers of employees at multi-employer worksites must notify other employers onsite in accordance with OSHA’s hazard communication standard.

135

Page 137: Chemical Hazards in Construction

Methylenedianiline in the

Construction Industry

136

Page 138: Chemical Hazards in Construction

Introduction

On August 10, 1992, the Occupational Safety and Health Administration (OSHA) issued a final standard regulating occupational exposure to 4,4' Methylenedianiline (MDA), the result of the agency's first negotiated rulemaking effort.

MDA is a light-brown crystalline solid with a faint amino-like odor. It is slightly soluble in water and very soluble in alcohol and benzene. MDA is produced commercially by the condensation of aniline and formaldehyde. Crude MDA (40 to 60 percent) is either a liquid or a hard wax-like substance. Purified MDA (99 percent) is either light yellow crystalline flakes or white granules.

Routes of exposure to MDA include skin absorption, inhalation, and ingestion. Short-term (acute) overexposure to MDA produces fever, chills, loss of appetite, vomiting, and/or jaundice. Short-term contact with MDA may irritate the skin, eyes, and mucous membranes and sensitization to MDA also may occur. Long-term (chronic) overexposure may cause cancer as well as damage to the liver, kidneys, blood, and spleen.

Ninety-eight percent of MDA currently produced is used directly in the manufacture of 4,4' Methylenediphenyl diisocyanate (MDI).1 The remaining 2 percent of MDA is used as a precursor in the manufacture of plastic fibers, antioxidants, dyestuff 1 Federal Register 57(154):35633, August 10, 1992.

137

Page 139: Chemical Hazards in Construction

intermediates, corrosion preventatives, and special polymers.Purified MDA is used in defense applications and inmanufacturing epoxy resin curing agents, wire coatingapplications, polyurethane co-reactants, and pigments anddyes.

In the construction industry, MDA is primarily used to coatexterior surfaces, such as concrete structures, pipes, andfloors. These surfaces located inside or outside of buildings,usually are coated by spray application. The standard,however, covers both spray and roll-on applications.

The following sections discuss the MDA standard as it pertainsto the construction industry. OSHA also has developed aseparate booklet that discusses the MDA standard's applicationto the general and maritime industries.

Scope and Application

The OSHA standard for exposure to MDA in the constructionindustry is outlined in Title 29 Code of Federal RegulationsPart 1926.60. The standard applies to all construction work inwhich there is exposure to MDA, including:

• construction, alteration, repair, maintenance, orrenovation of structures or portions thereof containingMDA;

138

Page 140: Chemical Hazards in Construction

• installation of, or finishing of surfaces with productscontaining MDA;

• MDA spill/emergency clean-up at construction sites; and• transportation, disposal, storage, or containment of MDA

or products containing MDA at construction sites.

Provisions of the StandardPermissible Exposure Limit

Time-Weighted Average and Short-Term Exposure Limit

No employee maybe exposed to MDA above the permissibleexposure limit (PEL) of 10 parts per billion (ppb) as an 8-hourtime-weighted average (TWA), or above a short-term exposurelimit (STEL) of 100 ppb over a 15-minute sampling period.

Action Level

The action level for a concentration of airborne MDA is 5 ppb asan 8-hour TWA. When the action level is reached, an employermust begin compliance activities such as exposure monitoring,medical surveillance, or temporary removal.

139

Page 141: Chemical Hazards in Construction

Regulated Areas

Regulated areas must be established where airborneconcentrations exceed the PEL or can reasonably be expectedto exceed the PEL and where employees handle or use non-airborne MDA liquids or mixtures. These areas must bedemarcated from the rest of the workplace to minimize thenumber of persons potentially exposed.

No eating, drinking, smoking, chewing of tobacco or gum, orappIying of cosmetics is permitted in regulated areas. Access toregulated areas must be limited to authorized persons only,and personal protective equipment and clothing are required tobe worn by employees working in these areas.

Decontamination Areas

Decontamination areas, located outside of but as near aspractical to the regulated area, also must be established fordecontaminating workers, materials, and equipmentcontaminated with MDA. The decontamination area mustinclude an equipment storage area, wash area, and cleanchange area.

Communication and Training Requirements

An employer performing work with MDA on multi-employer sitesmust inform other employers at the site of the nature of thework with MDA and the existence of requirements for regulatedareas.

140

Page 142: Chemical Hazards in Construction

Warning signs must be posted in each regulated area and at all entrances or accessways to regulated areas. These signs must bear the following information:

The employer must ensure that labels or other appropriate forms of warning are provided for containers of MDA anywhere in the workplace. The labels shall include the following legends:

Labels for containers of pure MDA must contain the following information:

Warning labels for containers of mixtures containing MDA must include the following information:

DANGER MDA

MAY CAUSE CANCER LIVER TOXIN

AUTHORIZED PERSONNEL ONLY RESPIRATORS AND PROTECTIVE CLOTHING ARE REQUIRED TO BE WORN IN THIS AREA

DANGER CONTAINS MDA

MAY CAUSE CANCER

DANGER CONTAINS MDA

CONTAINS MATERIALS WHICH MAY CAUSE CANCER

LIVER TOXIN

141

Page 143: Chemical Hazards in Construction

Material safety data sheets for MDA must be made available to employees in accordance with the OSHA Hazard Communication standard.2

Initial and annual employee training -- including an explanation of the MDA standard, the medical surveillance program, and the medical removal provisions -- are required as well. All written materials and information relating to employee training must be made available to all affected employees without cost.

Emergency Situations

The employer must develop a written plan for emergency situations for each construction operation. The employer must identify emergency escape routes at each specific construction site before construction operations begin. The plan also must require the use of appropriate protective equipment and clothing for employees and a means to alert and evacuate employees in the case of an emergency.

2 Under the provisions of the Hazard Communication standard, Title 29 CFR Part 1910.1200, employers must inform employees of the hazards and the identities of workplace chemicals to which they are exposed when working.

142

Page 144: Chemical Hazards in Construction

Exposure Monitoring

Breathing-zone air samples that are representative of each employee's exposure to airborne MDA over an 8-hour period will determine employee exposure. Determination of employee exposure to the STEL must be made from breathing zone air samples collected over a 15-minute sampling period. Representative employee exposure will be determined on the basis of one or more samples representing full-shift exposure for each shift for each job class in each work area where MDA exposure can occur. Where the employer can document that exposure levels are equivalent for similar operations in different shifts, the employer only is required to determine representative employee exposure for that operation during one shift.

The MDA standard requires that initial monitoring be performed for employees exposed to MDA unless objective or historical monitoring data prove that exposures are below the action level. (See section on Recordkeeping for requirements for monitoring data.) If exposure is at the PEL, monitoring must be repeated every 6 months; if above the PEL, every 3 months; if below the action level, monitoring may be discontinued.

The method of monitoring must be accurate to a confidence level of 95 percent and accurate to within plus or minus 25 percent for airborne concentrations of MDA.

When there is a change in the production process, chemicals present, control equipment, personnel, or work practices, new monitoring is required.

143

Page 145: Chemical Hazards in Construction

Within 15 working days, the employee must be notified in writing of monitoring results and must be informed of the corrective action the employer is taking to reduce exposures to or below the PEL when the PEL is exceeded. The employer is required to provide the employee or the employee representative(s) an opportunity to observe the measuring or monitoring of employee exposure to MDA.

The employer also must perform routine visual inspections of employee skin for dermal exposure (MDA turns skin yellow) and take appropriate corrective action when there is an indication of exposure. The employer must determine the source of exposure, implement protective measures to correct the hazard, and maintain all records of the corrective action.

MDA operations within a regulated area need not be monitored periodically if all employees are wearing supplied-air respirators while working in that regulated area.

144

Page 146: Chemical Hazards in Construction

Medical Surveillance

A medical surveillance program is required, under thesupervision of a licensed physician, without cost, for thoseemployees:

• exposed at or above the action level for more than 30days per year;

• subject to 15 or more days of dermal exposure;• exposed in an emergency; and• who show signs and symptoms of MDA exposure.

Initial medical exams are required before January 7, 1993, orbefore initial assignment and must include a detailed history,physical exam, lab tests including liver function tests andurinalysis, and any additional tests deemed necessary by thephysician. No initial medical exam is required, however, ifadequate records show the employee was examined accordingto the requirements listed above within the 6 months prior toJanuary 7, 1993, or the date of initial assignment.

The employer must conduct annual exams following the initialexam, emergency situations, or when the employee developssigns and symptoms associated with MDA exposure. Theexamining physician must provide in writing the results of theseexams to the employer and employee.

145

Page 147: Chemical Hazards in Construction

The employer must provide the examining physician(s) with:

• a copy of the MDA standard and its appendices;• a description of the affected employee's duties related to

potential MDA exposure;• the employer's current actual or representative MDA

exposure level;• a description of the protective equipment or clothing used;

and• information from previous employment-related medical

exams.

Multiple Physician Review Mechanism

When the employer selects the initial physician to conduct anymedical examination for the employee, the employee has theoption of a second medical opinion when the employee -- (1)has signs/symptoms of occupational exposure to MDA; (2)disagrees with the opinion of the examining physician; and/or(3) has questionable job status as a result of the physician'sopinion.

It is important to note that the employer must promptly informthe employee of the right to seek a second opinion following aninitial examination. The employer may condition hisparticipation in, and payment for, the multiple physician reviewmechanism upon the employee taking two actions within 15days after receipt of the first opinion -- (1) informing theemployer of the intention to seek a second opinion; and/or (2)initiating steps to make an appointment with a secondphysician.

146

Page 148: Chemical Hazards in Construction

If the second set of determinations differ from the initial ones,the employer must ensure the disagreement is resolvedbetween the two physicians. If unable to resolve such adisagreement quickly, the affected employee and employerthrough their physicians may designate a third physician toreview findings and conduct exams, tests, and discussions withthe prior physicians.

Medical Removal Provisions

An employer must temporarily remove an employee from workwhen occupational exposure to MDA is at or above the actionlevel or where dermal exposure to MDA may occur in thefollowing circumstances:

• following an initial exam;• following periodic exams;• following an emergency situation;• when an employee has signs/symptoms indicative of

acute MDA exposure; and/or• when the examining physician determines an employee's

abnormal liver function tests are not associated with MDAexposure but may be exacerbated as a result ofoccupational exposure to MDA.

147

Page 149: Chemical Hazards in Construction

The employer also must remove the employee each time a finalmedical determination3 results in a finding or opinion that theemployee has detected medical conditions that put him/her atan increased health risk from MDA exposure. The employermust implement special protective measures or establishlimitations for the employee when recommended by a finalmedical determination.

An employee may return to former job status when:

• he/she no longer shows signs or symptoms of MDAexposure;

• the physician so advises; or• a subsequent medical determination shows the employee

no longer has a detected medical condition that poses anincreased health risk from MDA exposure.

Limitations or special protective measures also may bediscontinued when a subsequent medical determination showsthem to be no longer necessary.

The employer must provide an employee up to 6 months ofmedical removal protection benefits4 each time the employee isremoved from MDA exposure. The employer, however, maycondition medical removal protection benefits on theemployee's participation in followup medical surveillanceprovided. If the removed employee files a worker'scompensation claim, the employer must continue to providemedical removal protection benefits pending disposition of theclaim.

3 A final medical determination is the outcome of the physician'sreview mechanism required through the medical surveillanceprovisions of the standard.

4 Medical removal protection benefits include maintaining theemployee's earnings, seniority, and other employment rightsand benefits as they would be if no removal had occurred.

148

Page 150: Chemical Hazards in Construction

When an employer voluntarily removes or places limitations onan employee who is exposed to MDA, medical removalprotection benefits are still required.

If an employee does not recover within 6 months of removalfrom MDA exposure, the employer must:

• make a medical exam available to obtain a final medicaldetermination;

• ensure the final medical determination indicates whetherthe employee can be returned to former job status and, ifnot, what steps to take to protect the employee's health;and

• continue to provide medical removal protection benefitsuntil the employee is returned to former status or a finalmedical determination shows that the employee isincapable of ever safely returning to former status.

149

Page 151: Chemical Hazards in Construction

Methods of ComplianceCompliance Program

The employer must establish and implement a writtencompliance program to reduce employee exposure to the PELor below by the use of engineering and work practice controlsand by the use of respiratory protection. Such plans must bereviewed every 12 months to ensure they reflect the currentstatus of operations.

Control Methods

Engineering and work practice controls are primary methodsused to reduce occupational exposure to MDA to levels at orbelow the PEL. To achieve compliance with the PEL, one or acombination of the following control methods must be used:

• local exhaust ventilation equipped with HEPA5 filtereddust collection systems;

• general ventilation systems;• other engineering controls, such as isolation and

enclosure; and• work practices.

5A high-efficiency particulate air (HEPA) filter is at least 99.97 ,percent efficient against mono-dispersed particles of 0.3micrometers or larger.

150

Page 152: Chemical Hazards in Construction

Where feasible engineering controls and work practices alone are not sufficient to reduce MDA exposure to the PEL or below, respiratory protection also is required. Specifically, for those employees engaged in spray application methods, respiratory protection is required in addition to feasible engineering controls and work practices to reduce exposures to or below the PEL.

Employee rotation, however, is prohibited as a means to reduce exposure. Compressed air may not be used to remove MDA unless it is used in conjunction with an enclosed ventilation system designed to capture the dust cloud created by the compressed air.

Respiratory Protection

Employers must provide, at no cost to the employee, and ensure the use of respirators when engineering and work practice controls are being installed; when engineering and work practice controls are not sufficient to reduce exposure to or below the PEL; when engineering controls are not feasible in repair or maintenance and spray application processes; and during emergencies.

Respirators must be selected from among those approved by the Mine Safety and Health Administration and the National Institute for Occupational Safety and Health (NIOSH). (See chart page 16.) Where respiratory protection is required, the employer must develop a respiratory protection program.

151

Page 153: Chemical Hazards in Construction

Respiratory Protection for MDA Airborne concentration of MDA or condition of use

Respirator type

a. Less than or equal to 10 x PEL

(1) Half-mask respirator with HEPA1 cartridge.2

b. Less than or equal to 50 x PEL

(1) Full-facepiece respirator with HEPA cartridge1 and canister.2

c. Less than or equal to 1000 x PEL

(1) Full-facepiece powered air-purifying respirator with HEPA1

cartridges.2 d. Greater than 1000 x PEL or unknown concentration

(1) Self-contained breathing apparatus with full facepiece in positive-pressure mode. (2) Full-facepiece positive- pressure demand supplied-air respirator with auxiliary self-contained air supply.

e. Escape (1) Any full-facepiece air-purifying respirator with HEPA1 cartridges2 (2) Any positive-pressure or continuous-flow self-contained breathing apparatus with full facepiece or hood

f. Firefighting (1) Full-facepiece self-contained breathing apparatus in positive-pressure mode.

Source: Federal Register 57(154):35684, August 10, 1992 Note: Respirators assigned for higher environmental conditions may be used at lower concentrations. 1High-Efficiency Particulate Air (HEPA) filter is one that is at least 99.97 percent efficient against mono-dispersed particles of 0.3 micrometers or larger. 2Combination HEPA/organic vapor cartridges shall be used whenever MDA is in liquid form or a process requiring heat is used. 16

152

Page 154: Chemical Hazards in Construction

If an employee cannot wear negative-pressure respirators, he/she must be given the option of wearing a positive-pressure respirator or a supplied-air respirator operated in continuous-flow or pressure-demand mode.

Where air-purifying respirators are used, the employer must replace the air-purifying element as needed to maintain effectiveness. Employees who wear respirators are allowed to leave the regulated area to adjust or readjust the facepiece or to wash their faces or respirator facepieces to minimize skin irritation associated with respirator use.

Quantitative or qualitative fit testing must be performed and recorded at the initial fitting and at least annually thereafter for each employee wearing a negative-pressure respirator.

Protective Clothing and Equipment

The employer must provide personal protective equipment and clothing, at no cost to the employee, and ensure their proper use when the employee is subject to dermal exposure to MDA; where liquids containing MDA can be splashed into the eyes; or where airborne concentrations of MDA are in excess of the PEL. Recommended protective clothing and equipment may include, but are not limited to aprons, coveralls, gloves, foot coverings, faceshields, and/or goggles.

153

Page 155: Chemical Hazards in Construction

Employees must use decontamination areas to remove MDA-contaminated work clothing and equipment at the end of the workshift. Employers also must ensure that during their workshift, employees remove all MDA-contaminated protective clothing or equipment prior to leaving a regulated area.

All protective clothing and equipment must be cleaned, laundered, repaired, or replaced as needed to maintain effectiveness. When rips or tears are detected, the personal protective equipment and clothing must be repaired or replaced immediately.

No MDA-contaminated protective work gear may be removed from a decontamination area except by authorized employees for laundry, maintenance, or disposal. MDA-contaminated items must be placed, stored, and transported in sealed, labeled, and closed containers or impermeable bags. Removal of MDA via blowing, shaking, or any method that allows MDA reentry into the workplace is prohibited. The employer must inform those responsible for laundering or cleaning protective clothing and equipment of the potential harmful effects of MDA exposure.

Hygiene Facilities and Practices The employer must provide decontamination areas for those employees required to work in regulated areas. In small-scale short-term operations, however, the employer may permit

154

Page 156: Chemical Hazards in Construction

employees to clean their protective clothing or dispose of it before leaving the regulated area.

Change areas must be equipped with separate storage facilities for personal protective equipment and clothing and street clothing.

The equipment area must be supplied with impermeable labeled bags and containers for the disposal of contaminated protective equipment and clothing. If these bags or containers and their contents are to be removed from the workplace to be cleaned, disposed of, or maintained, they must be labeled and sealed to prevent MDA contact.

When feasible, shower facilities must be provided where the possibility exists of employee exposure to airborne MDA in excess of the PEL.

Where dermal exposure to MDA occurs, the employer must ensure that materials spilled or deposited on the skin are removed as soon as possible.

Whenever food or beverages are consumed at the work site and employees are exposed to MDA, the employer must provide clean lunch areas where MDA levels are below the action level or where no dermal exposure to MDA can occur. Prior to eating, drinking, smoking, or applying cosmetics, employees must wash their hands and faces with soap and water. No one may enter lunch facilities with contaminated protective work clothing or equipment.

155

Page 157: Chemical Hazards in Construction

Housekeeping

All surfaces must be maintained as free as possible of accumulations of MDA. A regular visual inspection program must be instituted to detect MDA leaks, spills, or discharges. All leaks must be repaired, and liquid or dust spills promptly cleaned. The use of compressed air for cleaning is prohibited, but shoveling or dry sweeping is permissible where HEPA-filtered vacuuming or wet cleaning is not feasible. In any case, contaminated debris -- including waste, scrap, debris, bags, containers, equipment and clothing contaminated with MDA -- must be collected and disposed of in a manner that prevents re-entry of MDA into the workplace.

Recordkeeping

All records must be made available to affected employees or their representative(s), OSHA, and NIOSH upon request in accordance with the Access to Employee Exposure and Medical Records standard, Title 29 CFR Part 1910.20. If the employer ceases to do business, all records must be transferred to successor employers or, if there is no successor, to NIOSH.

In addition, the MDA standard has specific requirements for keeping records pertaining to objective and historical monitoring data and training.

156

Page 158: Chemical Hazards in Construction

Objective Data

Under the MDA standard, an accurate record must bemaintained of initial monitoring or of the objective data thatexempted the operations from initial monitoring requirements.The record must be kept for the duration of reliance on the dataand must include at least the following information:

• the product qualifying for exemption;• the source of the objective data;• the testing protocol, testing results, and/or analysis of

material for release of MDA;• a description of the exempted operation and how the data

support that exemption; and• other data relevant to the operations, materials,

processing, or employee exposures covered by theexemption.

Historical Monitoring Data

The MDA standard also requires that an accurate record bekept of all historical data upon which the employer has relied todemonstrate that a particular job will be below the action levelto exempt initial monitoring requirements. The information mustreflect the following conditions:

• the data are scientifically sound and are collected usingsufficiently accurate and precise methods;

157

Page 159: Chemical Hazards in Construction

• the processes and work practices used were obtained inessentially the same manner as those that would havebeen used during the job for which initial monitoring willnot be performed;

• the characteristics of the MDA-containing material beinghandled are the same as those on a job for which initialmonitoring will not be performed;

• environmental conditions obtained were the same asthose for which initial monitoring will not be performed;and

• other relevant data on the operations, materials,processing, or employee exposures covered by theexemption are substantially similar.

The MDA construction standard allows, however, the employerto maintain historical records through the services of competentorganizations, such as a trade association or an employeeassociation.

Exposure Measurements and Medical Surveillance

The employer must keep an accurate record of allmeasurements taken to monitor employee MDA exposure for atleast 30 years. This record must include:

• the date of measurement;• the operation involving MDA exposure;• the sampling and analytical methods used and evidence

of their accuracy;

158

Page 160: Chemical Hazards in Construction

• the number, duration, and results of samples taken; adescription of the type of respiratory protective devicesused; and

• the name, social security number, and exposure of theemployees whose exposures are represented through theinformation.

Similarly, the employer must maintain for at least 30 years anaccurate record of each employee subject to medicalsurveillance, including:

• the name and social security number of the employee;• the medical exam results, including medical history, test

results, and physician's recommendations;• the examining physician's written opinions;• any employee medical complaints related to MDA

overexposure; and• a copy of all information provided to the examining

physician.

Training Records

The MDA standard requires employers to maintain all employeetraining records for 1 year beyond the last date of theemployee's employment.

159

Page 161: Chemical Hazards in Construction

The Hazards of Crystalline Silica Dust

160

Page 162: Chemical Hazards in Construction

1

Contents

Introduction ____________________________________________________ 2

What is silicosis? _________________________________________________ 3Silicosis is a lung disease caused by breathing dust containingparticles of crystalline silica.

Who should be concerned about silicosis? ______________________ 4You should be concerned about silicosis if your workplace is dustyand uses materials that contain crystalline silica.

How do you prevent silicosis?___________________________________ 4The most important thing you can do to prevent silicosis is toeliminate crystalline silica dust from your workplace.

How much crystalline silica is hazardous? ______________________ 7The answer depends on a worker’s exposure level and on acalculation called the permissible exposure limit.

Determining when crystalline silica dust is hazardous —two examples ___________________________________________________ 8

Here’s how an industrial hygienist might use the permissibleexposure limit to find out if a worker is overexposed to crystallinesilica dust.

Key terms _______________________________________________________ 11

161

Page 163: Chemical Hazards in Construction

Silicosis: What you should know about it and how to prevent it

Introduction

Silicosis is an occupationaldisease caused by exposureto dust from crystalline silica,

one of the most common mineralson our planet.

Silicosis isn’t curable — sadly,workers still die from the disease —but it is preventable. The keys toprevention are straightforward:Identify workplace activities thatproduce crystalline silica dust andthen eliminate the dust or control itso that workers aren’t exposed.

You may be using products ormaterials that contain crystallinesilica and not even know it. If yourworkplace is a dusty one or if youwork with materials that producedust, you should be concerned aboutsilicosis and crystalline silica hazards.

We want to advance and improveworkplace safety and health for allworking Oregonians. One way todo that is to inform you about work-place hazards you can control —and crystalline silica is one of thosehazards. This guide will help youlearn about silicosis, what causes it,and how to prevent it.

2

162

Page 164: Chemical Hazards in Construction

What is silicosis?

Silicosis is a progressive,disabling lung disease causedby breathing dust containing

particles of crystalline silica —particles so small you can see themonly with a microscope. The cause ofsilicosis has been known for centuries— the earliest cases of silicosis wererecorded before the first century —yet workers continue to die every yearfrom the disease. Crystalline silicaexists almost everywhere in ournatural environment. It’s abundant insoil, sand, dust, quartz, and graniterock. Not surprisingly, crystallinesilica also exists in products that wemake or use every day at home and atwork. For example, china tableware ismade from materials containing silicaflour, which is finely ground quartz.And unwashed root vegetables likepotatoes are coated with soil contain-ing crystalline silica — a possiblehealth hazard for those who harvest,sort, and bag them without appropri-ate exposure controls.

Keep in mind that crystallinesilica can cause silicosis only whenwe breathe it into our lungs as dust ora fine powder. Here’s what happens:The silica particles become trapped inthe lungs and damage the tissue. As aresult, the lung tissue scars and formssmall, rounded masses called nodules.Over time, the nodules grow, makingbreathing increasingly difficult.

Though silicosis shows no symp-toms at first, the victim eventually hastrouble breathing and develops asevere cough. Other symptomsinclude fatigue, loss of appetite, chestpains, and fever. Only a completework history, a chest X-ray, and alung-function test will determine

whether or not a worker has thedisease. Those who think they mayhave silicosis shouldsee a medical doctorwho specializes inoccupational medicine.

Chronic silicosis

Silicosis can affectyou in three ways.Most workers who getsilicosis don’t showany symptoms for 10or more years. That’sbecause their expo-sures to crystallinesilica are fairly low, butfrequent. They developa condition calledchronic silicosis.

Acceleratedsilicosis

As exposure levelsincrease, however,silicosis symptoms canappear much earlier.For example, thosediagnosed with accel-erated silicosis showsymptoms within fiveto 10 years.

Acute silicosisWorkers exposed to

extremely high levelsof crystalline silicadust may develop acute silicosis, acondition that can show symptomswithin only a few weeks of an initialexposure. Acute silicosis is mostcommon among sand blastersbecause of the high levels of silicadust they breathe.

3

About crystalline silicaWhat is it?Crystalline silica is the scientificname for a group of mineralscontaining silicon and oxygen.Crystalline means that the oxygenand silicon atoms are arranged ina specific pattern.

Forms of crystalline silicaCrystalline silica exists in severalforms, including quartz, cristobalite,and tridymite. Tridymite is the mostpotent, but least common form.Cristobalite, which occurs naturallyin volcanic rock, is often foundwith quartz in the Pacific Northwest.Of these forms, quartz is the mostcommon; in fact it’s the secondmost common mineral on the planet.(Feldspar is most common.)The cause of silicosis is linkedto cancerCrystalline silica causes silicosis,but it has also been linked to cancer.As a result, any material thatcontains more than 0.1 percentcrystalline silica must meet thelabeling, information, and trainingrequirements of the HazardCommunication Standard(Subdivision 2/Z, 1910.1200).

163

Page 165: Chemical Hazards in Construction

Silicosis: What you should know about it and how to prevent it

Who should beconcerned aboutsilicosis?

Any worker exposed to dustcontaining crystalline silica— dust from crushed rock,

soil, dirt, gravel, or sand, for example— should be concerned about silico-sis. In fact, more than 100,000workers in this country are exposedevery year. The following tableshows some of the activities that putthem at risk.

Because crystalline silica is sucha common mineral — so prominentin the products that we make and use— you should be concerned aboutworking with any material thatcontains more than 0.1 percentcrystalline silica.

How do youprevent silicosis?

T he best way to preventsilicosis is to identify work-place activities that produce

crystalline silica dust and then toeliminate or control the dust.

How to identify activitiesthat produce crystallinesilica dust

Do you know what activities atyour workplace expose workers tocrystalline silica dust? Suspect anyactivity that produces dust from rock,soil, dirt, gravel, sand, or any productmade from these materials.

If you haven’t done so, make a listof the suspect activities.

Then, determine which of thoseactivities put work-ers at risk. Anindustrial hygienistcan help you makethat determinationby sampling the airworkers breathe andcalculating a per-missible exposurelimit (PEL). (SeeHow much crystal-line silica is hazardous? Page SEVEN.)

Activities that could put workers at risk:

ManufacturingMetal castingGlass productsCeramics, clay and potteryAsphalt paving materialCut stone and stone productsAbrasivesPaint and rubber productsFiltered foods and beverages

ConstructionChipping, hammering, and drilling rockCrushing, loading, hauling, and dumping rockAbrasive blastingSawing, hammering, drilling, grinding, andchipping masonry or concreteDemolition of concrete or masonry structuresDry sweeping or using pressurized air to blowconcrete, rock or sand dust

AgricultureOnion harvesting, topping, sorting, grading, andbaggingPotato harvesting, sorting, grading, washing, andbagging

A key termThe permissibleexposure limit (PEL)is the maximumamount of airbornecrystalline silicadust that one can beexposed to during afull work shift.

164

Page 166: Chemical Hazards in Construction

How to eliminate or con-trol crystalline silica dust

Once you’ve identified activitiesthat expose workers to hazardouslevels of crystalline silica, you needto eliminate the exposure or controlit so that it isn’t hazardous. How canyou eliminate or control crystallinesilica exposures at your workplace?Here are some suggestions:

Use substitutes. The best way toeliminate exposure is to usematerials that don’t containcrystalline silica. This is anexample of the “engineering”approach to hazard control. Theengineering approach eliminateshazards by selecting tools andequipment and by designingwork processes that are hazard-free. Examples of materials thateliminate crystalline-silicaexposure include the following:

Use dust-containment systems.Other ways to eliminate exposureinclude installing dust-collectionsystems on machines that gener-ate dust or using enclosed cabi-nets with gloved armholes to dohazardous tasks.

Work wet. Use wet drilling orsawing methods to control dust.Remove dust and debris with awet vacuum or hose it downrather than blowing it aroundwith compressed air or dry-sweeping it.

Ventilate. Use local-exhaustventilation systems to keep workareas dust free.

Use personal protective equip-ment when it’s necessary.Personal protective equipmentcan protect workers from haz-ards, but it doesn’t eliminatehazards. If the equipment fails,or it’s not appropriate for aparticular task, a worker can stillbe exposed.

Respirators are a special type ofpersonal protective equipment.When carefully selected, worn,and used, respirators will protectworkers from inhaling crystallinesilica dust. But you should usea respirator only if you can’teliminate or control the dust withany other method, and you needto understand the requirementsfor using respirators. (See theRespiratory Protection Standard,Subdivision 2/I, 1910.134 formore information on usingrespirators properly.) Don’t usea respirator as your only meansof protection!

aluminum oxidealuminum shotambient polycarbonateapricot pitscorn cobscryogenic polycarbonateemerygarnetglass beadsmelamine plasticnovaculitepolycarbonatesilicon carbidestainless cast shotstainless cut wiresteel gritsteel shoturea plasticwalnut shellswheat grainwhite aluminum oxidezircon

5

165

Page 167: Chemical Hazards in Construction

Silicosis: What you should know about it and how to prevent it

Monitor the air and workers’health. Air monitoring is amethod of determining workers’exposures to silica dust (See Howmuch crystalline silica is hazard-ous? Page SEVEN.) Air monitor-ing results can also help youdecide the most appropriatemethods for controlling crystal-line silica dust.

Workers who may be exposed tocrystalline silica dust should haveregular medical exams. Theyshould be examined before theybegin their jobs and at least everythree years thereafter. Examina-tions should include medical andwork histories, chest X-rays, andtuberculosis evaluations. Medicalexaminations should supplementair monitoring and other controlmethods — not replace them.

Practice good personal hygiene.Those who work with materialscontaining crystalline silicashould wash their hands before

eating, drinking, or smoking.They should shower, if possible,and change into clean clothesbefore leaving the worksite. Theyshould never eat, drink, or usetobacco in abrasive blastingareas.

Train and educate. Make sureworkers know about silicosis,silica-dust hazards, and how tocontrol their exposure. Theirtraining and education shouldcover the following:

The health effects of exposureto crystalline silica

The importance of effectivecontrols, safe work practices,and personal hygiene

How to use material safetydata sheets (MSDSs) forsilica, masonry products, andabrasives. (See the HazardCommunication Standard formore information on materialsafety data sheets.)

The purpose of boundaries orsigns that identify work areascontaining crystalline silicadust

How to safely handle, label,and store hazardous materials

How to use and care forpersonal protective equipment

For more information on silica-hazards training, see the HazardCommunication Standard.

6

Guidelines for preventing silicosis

Identify work areas, tasks, and equipment that exposeworkers to crystalline silica dust.Use materials that don’t produce crystalline silica.Work wet and use dust-containment systems to controldust.Ventilate to keep work areas dust free.Use personal protective equipment when necessary.(See the Respiratory Protection Standard, Subdivision 2/I,1910.134, for more information on using respirators properly.)Monitor the air to determine worker exposure levels.Give exposed workers regular medical exams.Practice good personal hygiene.Educate workers about silica-dust hazards and silicosis;train them how to control their exposure.Label products that contain crystalline silica.

166

Page 168: Chemical Hazards in Construction

Communicate and inform.Make sure any product thatcontains silica has a label thatsays so. Materials or productsthat contain more than 0.1 per-cent crystalline silica must have amaterial safety data sheet. (Seethe Hazard CommunicationStandard for more information onlabeling and material safety datasheets.)

Post warning signs. Put up signsthat identify the work areas,tasks, and equipment that mayexpose workers to crystallinesilica. The signs should warnworkers about crystalline-silicahazards and identify any requiredpersonal protective equipment.

How muchcrystalline silicais hazardous?

U nfortunately, there’s not asimple answer that you canapply to every task or

workplace. How much crystallinesilica is hazardous depends on aworker’s exposure to crystallinesilica and on a calculated valuecalled the permissible exposure limit(PEL). The permissible exposurelimit is the maximum amount ofairborne crystalline silica dust thatone can be exposed to during a fullwork shift.

A trained specialist, such as anindustrial hygienist, can determinewhether a worker is overexposed bysampling the air a worker breathesand calculating a permissible expo-sure limit. Here’s how an industrialhygienist makes the determination:

First, the hygienist will collect anair sample in the worker’s breathingzone. She’ll have a laboratory ana-lyze the sample to determine theweight of the dust present and thepercentage of free crystalline silica inthe sample.

Then she’ll use the percentage offree silica in an equation to calculatea value for the permissible exposurelimit. She’ll compare the permissibleexposure limit value with the weightof the respirable dust from thesample. If the weight of the respi-rable dust is greater than the permis-sible exposure limit, then the workeris overexposed to crystalline silica.The following examples describethese calculations in more detail.

I’m an employer. What do I do ifan employee is overexposed tocrystalline silica?

The first thing you should do is tellthe employee. You should also makesure the employee gets a medicalexamination from an occupationalmedical doctor.

Then, eliminate the exposure. Ifyou can’t do that, you’ll need to controlit to prevent overexposure by doingone or more of the following:

Use a silica substituteUse engineering controlsImprove work practicesUse personal protective equipment

Also, review How do you preventsilicosis? (Page FOUR)

7

167

Page 169: Chemical Hazards in Construction

Silicosis: What you should know about it and how to prevent it

Determining when crystalline silica dustis hazardous — two examples

Example 1Determining the PEL for crystalline silica quartz

This example highlights the calculations an industrial hygienist mightuse to determine if a worker was exposed to unsafe levels of crystal-line silica quartz dust. Recall that crystalline silica quartz is the most

common form of crystalline silica; other forms are tridymite and cristobalite.

The permissible exposure limit (PEL) for crystalline silica quartz is basedon the following equation and is expressed in milligrams per cubic meter(mg/m3).

Assume the hygienist sampled the air near a worker using a rock-grindingmachine. She had a laboratory analyze the sample to determine the weight ofrespirable dust and the percentage of free silica quartz. The laboratory re-ported the following results:

She plugged 25 percent into the PEL equation and calculated a value of0.37 mg/m3, as shown below.

The weight of airborne respirable dust in the sample = 0.45 mg/m3

The calculated PEL value = 0.37 mg/m3

0.45 mg/m3 is greater than 0.37 mg/m3

Therefore, the worker is overexposed

Because the weight of the airborne breathable dust in the sample (0.45mg/m3) is greater than the calculated PEL value (0.37 mg/m3), the hygienistconcludes that the worker is overexposed.

PEL(Crystalline

silica quartz)

10 mg/m3

[Percentage of free silica quartz in an air sample] + 2=

PEL(Crystalline

silica quartz)

10 mg/m3

25 + 2= = 0.37 mg/m3

Results

Labreport

What was sampled Value

Weight of respirable silica dust 0.45 mg/m3

Percentage of free silica quartz 25.00%

168

Page 170: Chemical Hazards in Construction

Example 2Determining the PEL for crystalline silica quartz and cristobalite

In this example, the hygienist sampled the air in the breathing zone of aworker using a jackhammer on concrete. The laboratory has reported thefollowing results:

What was sampled ValueWeight of respirable silica dust 30.00 mg/m3

Percentage of free silica quartz 6.50%Percentage of cristobalite 3.20%

To calculate the PEL for crystalline silica quartz and cristobalite, thehygienist plugs the above results into the PEL equation (below).

To calculate the worker’s exposure, compare the concentration of respirabledust with the calculated PEL as shown below.

The weight of airborne breathable dust in the sample = 30.00 mg/m3

The calculated PEL value = 0.67 mg/m3

30.00 mg/m3 is greater than 0.67 mg/m3

Therefore, the worker is overexposed

Because the concentration of respirable dust (30 mg/m3) is greater thanthe calculated PEL value (0.67 mg/m3), the worker is overexposed to respi-rable dust containing crystalline silica quartz and cristobalite.

Labreport

Results

PEL 10 mg/m3

Percentage of free silica quartz + 2 (Percentage of cristobalite) + 2=

0.67 mg/m3=

10 mg/m3

6.50 + 2(3.20) + 2=

169

Page 171: Chemical Hazards in Construction

Key terms

Accelerated silicosis A form of silicosis that shows symptoms within five to 10years.

Acute silicosis A form of silicosis that develops in workers exposed to veryhigh levels of crystalline silica. Symptoms may appearwithin only a few weeks of an initial exposure.

Chronic silicosis The most common form of silicosis. Workers usuallydon’t show symptoms for ten years or more after an initialexposure.

Cristobalite A form of crystalline silica that is stable at the highesttemperature. It occurs naturally in volcanic rock.

Crystalline Having a very structured molecular arrangement

Exposure control A means of eliminating or reducing workplace hazards.Examples include engineering, work-practice, and adminis-trative controls.

Free crystalline silica Pure crystalline silica that is chemically uncombined.

Hazard Communication Standard (Subdivision 2/Z, 1910.1200). Ensures that chemical hazardsare properly evaluated and that employers and their employ-ees understand the hazards. Requirements focus on properlabeling, material safety data sheets, and training.

Industrial hygienist A health professional trained to recognize, evaluate anddevelop controls for occupational health hazards.

Material safety data sheet (MSDS) Printed material that describes a hazardous chemical inaccordance with the Hazard Communication Standard.

Mineral Naturally occurring crystalline solids, usually made fromoxygen, silicon, sulfur, and any of six common metals ormetal compounds.

Permissible exposure limit (PEL) The maximum amount of airborne crystalline silica dust thatone can be exposed to during a full work shift.

Quartz The most common type of crystalline silica.

Respirable dust Dust that contains particles small enough to enter the gas-exchange region of the human lung. (about 3.5 microns).

Respiratory Protection Standard Identifies what employers must do to ensure their employeesuse respirators safely and responsibly. (Subdivision 2/I,1910.134)

Silicosis A disease that results from exposure to high levels of respi-rable silica dust and characterized by scarred lung tissue.

Tridymite A form of crystalline silica found in volcanic rocks and infired silica bricks.

11170

Page 172: Chemical Hazards in Construction

“Crystalline Silica Exposure”Health Hazard Information

for Construction Employees

What is crystalline silica?Crystalline silica is a basic component of soil, sand, granite, andmany other minerals. Quartz is the most common form of crystallinesilica. Cristobalite and tridymite are two other forms of crystalline silica.All three forms may become respirable size particles when workers chip,cut, drill, or grind objects that contain crystalline silica.

What are the hazards of crystalline silica?Silica exposure remains a serious threat to nearly 2 million U.S. workers,including more than 100,000 workers in high risk jobs such as abrasiveblasting, foundry work, stonecutting, rock drilling, quarry work andtunneling. The seriousness of the health hazards associated with silicaexposure is demonstrated by the fatalities and disabling illnesses thatcontinue to occur in sandblasters and rockdrillers. Crystalline silica hasbeen classified as a human lung carcinogen. Additionally, breathingcrystalline silica dust can cause silicosis, which in severe cases can bedisabling, or even fatal. The respirable silica dust enters the lungs andcauses the formation of scar tissue, thus reducing the lungs’ ability totake in oxygen. There is no cure for silicosis. Since silicosis affectslung function, it makes one more susceptible to lung infections liketuberculosis. In addition, smoking causes lung damage and adds tothe damage caused by breathing silica dust.

What are the symptoms of silicosis?

Silicosis is classified into three types: chronic/classic, accelerated,and acute.

Chronic/classic silicosis, the most common, occurs after 15–20years of moderate to low exposures to respirable crystalline silica.Symptoms associated with chronic silicosis may or may not beobvious; therefore, workers need to have a chest x-ray to determineif there is lung damage. As the disease progresses, the worker mayexperience shortness of breath upon exercising and have clinicalsigns of poor oxygen/carbon dioxide exchange. In the later stages,the worker may experience fatigue, extreme shortness of breath,chest pain, or respiratory failure.

Accelerated silicosis can occur after 5–10 years of high exposuresto respirable crystalline silica. Symptoms include severe shortnessof breath, weakness, and weight loss. The onset of symptoms takeslonger than in acute silicosis.

Acute silicosis occurs after a few months or as long as 2 yearsfollowing exposures to extremely high concentrations of respirablecrystalline silica. Symptoms of acute silicosis include severedisabling shortness of breath, weakness, and weight loss, whichoften leads to death.

For more information, contact your local OSHA office (listed in thetelephone directory under United States Government—Departmentof Labor—Occupational Safety and Health Administration) or visitOSHA’s website at www.osha.gov <http://www.osha.gov>.171

Page 173: Chemical Hazards in Construction

U.S

. Dep

artm

ent o

f Lab

orO

ccup

atio

nal S

afet

y an

d H

ealth

Adm

inis

trat

ion

OSH

A 31

7720

02 (R

evis

ed)

Where are construction workers exposedto crystalline silica?Exposure occurs during many different constructionactivities. The most severe exposures have occurred duringabrasive blasting with sand to remove paint and rust frombridges, tanks, concrete structures, and other surfaces.Other construction activities that may result in severeexposure include: jack hammering, rock /well drilling,concrete mixing, concrete drilling, brick and concrete blockcutting and sawing, tuck pointing, tunneling operations.

How is OSHA addressing exposureto crystalline silica?OSHA has an established Permissible Exposure Limit,or PEL, which is the maximum amount of crystallinesilica to which workersmay be exposed during an 8-hourwork shift (29 CFR 1926.55,1910.1000). OSHA alsorequires hazard communication training for workersexposed to crystalline silica, and requires a respiratorprotection program until engineering controls areimplemented. Additionally, OSHA has a National EmphasisProgram (NEP) for Crystalline Silica exposure to identify,reduce, and eliminate health hazards associated withoccupational exposures.

■■■■■ Replace crystalline silica materials with safer substitutes, whenever possible.■■■■■ Provide engineering or administrative controls, where feasible, such as

local exhaust ventilation, and blasting cabinets. Where necessary toreduce exposures below the PEL, use protective equipment or otherprotective measures.

■■■■■ Use all available work practices to control dust exposures, such as watersprays.

■■■■■ Wear only a N95 NIOSH certified respirator, if respirator protectionis required. Do not alter the respirator. Do not wear a tight-fittingrespirator with a beard or mustache that prevents a good seal betweenthe respirator and the face.

■■■■■ Wear only a Type CE abrasive-blast supplied-air respirator for abrasiveblasting.

■■■■■ Wear disposable or washable work clothes and shower if facilities areavailable. Vacuum the dust from your clothes or change into cleanclothing before leaving the work site.

■■■■■ Participate in training, exposure monitoring, and health screening andsurveillance programs to monitor any adverse health effects caused bycrystalline silica exposures.

■■■■■ Be aware of the operations and job tasks creating crystalline silica exposuresin your workplace environment and know how to protect yourself.

■■■■■ Be aware of the health hazards related to exposures to crystalline silica.Smoking adds to the lung damage caused by silica exposures.

■■■■■ Do not eat, drink, smoke, or apply cosmetics in areas where crystallinesilica dust is present. Wash your hands and face outside of dusty areasbefore performing any of these activities.

■■■■■ Remember: If it’s silica, it’s not just dust.

What can employers/employees do toprotect against exposures to crystalline silica?

172