HETA 96–0226–2640 Lehigh Portland Cement Company Union … · 2002-06-14 · Daniel Almaguer...

HETA 96–0226–2640Lehigh Portland Cement Company

Union Bridge, Maryland

Wayne T. SandersonDaniel Almaguer

This Health Hazard Evaluation (HHE) report and any recommendations made herein are for the specific facility evaluated and may not be universally applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved. Additional HHE reports are available at http://www.cdc.gov/niosh/hhe/reports



This Health Hazard Evaluation (HHE) report and any recommendations made herein are for the specific facility evaluated and may not be universally applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved.


applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved. Additional HHE reports are available at http://www.cdc.gov/niosh/hhe/reports

http://www.cdc.gov/niosh/hhe/reports



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PREFACEThe Hazard Evaluations and Technical Assistance Branch of NIOSH conducts field investigations of possiblehealth hazards in the workplace. These investigations are conducted under the authority of Section 20(a)(6)of the Occupational Safety and Health Act of 1970, 29 U.S.C. 669(a)(6) which authorizes the Secretary ofHealth and Human Services, following a written request from any employer or authorized representative ofemployees, to determine whether any substance normally found in the place of employment has potentiallytoxic effects in such concentrations as used or found.

The Hazard Evaluations and Technical Assistance Branch also provides, upon request, technical andconsultative assistance to Federal, State, and local agencies; labor; industry; and other groups or individualsto control occupational health hazards and to prevent related trauma and disease. Mention of company namesor products does not constitute endorsement by the National Institute for Occupational Safety and Health.

ACKNOWLEDGMENTS AND AVAILABILITY OF REPORTThis report was prepared by Wayne T. Sanderson and Daniel Almaguer, of the Hazard Evaluations andTechnical Assistance Branch, Division of Surveillance, Hazard Evaluations and Field Studies (DSHEFS).Desktop publishing by Kate L. Marlow. We wish to acknowledge special assistance during the plant surveyby Mr. Harvey Kirk III, Mr. James Harris, and the employees of the Lehigh Portland Cement Company.

Copies of this report have been sent to employee and management representatives at the Lehigh PortlandCement Company, and the Mine Safety and Health Administration (MSHA) Regional Office in Pittsburgh,Pennsylvania. This report is not copyrighted and may be freely reproduced. Single copies of this report willbe available for a period of three years from the date of this report. To expedite your request, include aself–addressed mailing label along with your written request to:

NIOSH Publications Office4676 Columbia ParkwayCincinnati, Ohio 45226

800–356–4674

After this time, copies may be purchased from the National Technical Information Service (NTIS) at 5825Port Royal Road, Springfield, Virginia 22161. Information regarding the NTIS stock number may beobtained from the NIOSH Publications Office at the Cincinnati address.

For the purpose of informing affected employees, copies of this report shall beposted by the employer in a prominent place accessible to the employees for aperiod of 30 calendar days.

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Health Hazard Evaluation Report HETA 96–0226Lehigh Portland Cement Company

Union Bridge, MarylandMay 1997

Wayne T. SandersonDaniel Almaguer

SUMMARYOn July 17, 1996, the National Institute for Occupational Safety and Health (NIOSH) received a request fromthe Safety and Training Supervisor of the Lehigh Portland Cement plant in Union Bridge, Maryland, for helpin evaluating an “unidentifiable bleach odor” inside one of the cement kilns. The odor was noticeable onlywhen the kiln was shut down for maintenance. Maintenance personnel working inside the kiln reportedrespiratory and eye irritation. The kiln operates continuously throughout the year and no health hazard hadbeen reported during normal operations. Therefore, the health hazard evaluation was placed on hold untilthe next scheduled maintenance period. NIOSH was notified on November 21, 1996, that the kiln would beshut down for repair from December 2 until December 5, 1996.

On December 3, 1996, workers entered the kiln to remove and replace 25 feet of refractory brick at thefront–end of the kiln. Reported symptoms experienced by workers during previous maintenance operationssuggested that they had been exposed to irritant gases or dusts. Personal breathing zone (PBZ) samples werecollected for chlorine, sulfur dioxide, and respirable and total dust. Area samples were collected at threesampling locations inside the kiln for chlorine, inorganic acid, sulfur dioxide, oxides of nitrogen, ozone,respirable, total, and inhalable dusts. Respirable dust samples were further analyzed for crystalline silica,and total dust samples were further analyzed for arsenic, cadmium, copper, chromium, magnesium, nickel,and zinc content.

Chlorine was not detected on any PBZ samples and only trace concentrations of sulfur dioxide were detectedwhile workers were working inside the kiln. None of the PBZ or area dust samples exceeded the applicableoccupational exposure criteria. Quartz and cristobalite were not detected in any of the dust samples. Areasampling for chlorine and inorganic acid showed no detectable concentrations inside the kiln. Ozone wasnot detected at any location while workers were inside the kiln.

After work inside the kiln had been completed and all workers had exited the kiln, the conditions presentduring previous episodes were recreated. The electrostatic precipitator serving kiln #4 was reduced to halfstrength, the east precipitator unit was turned on, and the west precipitator unit and the induced draft fan wereturned off. Chlorine and ozone measurements were then collected from outside the kiln. Chlorine was notdetected at the front end of the kiln. However, ozone was detected at concentrations of 0.6 to 0.7 ppm ontwo ozone color indicator tubes (0.09 to 0.11 ppm ozone was detected using a Metrosonic pm–7700 ToxicGas Monitor). Background readings for ozone in the plant yard were 0.02 to 0.03 ppm.

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Chlorine and ozone measurements were also collected through a portal at the back end of the kiln. Chlorinewas not detected. However, an ozone indicator tube was saturated after two pump strokes, indicating thatozone concentrations inside the kiln were well above 0.7 ppm. A direct reading meter reveled aconcentration of 4.5 ppm. The NIOSH recommended exposure limit (REL) is 0.1 ppm as a 15-minute ceilinglimit. Afterwards, the electrostatic precipitator was turned completely off and the induced draft (ID) fan wasturned on. Within 10 minutes the ozone concentration detected by the direct reading meter dropped to 0.16ppm and within one–half hour the meter readings had decreased to background levels.

Occurrences of eye and upper respiratory irritation during kiln repair activities can be causallyrelated to ozone exposures. Ozone generated by an operating electrostatic precipitator back–draftedinto the kiln when the induced draft fan was turned off. Experimental recreations of events resultedin ozone concentrations inside the kiln approaching 5 ppm, 50 times the NIOSH ceiling of 0.1 ppm.It is reasonable to assume that similar exposures were encountered during previous kiln maintenanceoperations. Although dust measurements did not indicate that workers performing maintenanceinside the kiln were exposed to excessive concentrations of dust, crystalline silica, or metals,respirators can reduce concentrations of inhaled dust particles which may dry and irritate nasalpassages and upper airways.

Keywords: SIC 3241 (Portland cement manufacturing), Portland cement, kiln maintenance, electrostaticprecipitator, ozone, respiratory irritation

TABLE OF CONTENTS

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

Acknowledgments and Availability of Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Evaluation Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Ozone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Chlorine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Sulfur Dioxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Particulates, Not Otherwise Classified . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Silica (amorphous, quartz, cristobalite) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Metals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Health Hazard Evaluation Report No. HETA 96–0226

INTRODUCTIONOn July 17, 1996, the National Institute forOccupational Safety and Health (NIOSH)received a request from the Safety and TrainingSupervisor of the Lehigh Portland Cement plant inUnion Bridge, Maryland, for help in evaluating an“unidentifiable bleach odor” inside one of thecement kilns. The odor was only noticeable whenthe kiln was shut down for maintenance.Maintenance personnel working inside the kilnreported respiratory and eye irritation. The kilnoperates continuously throughout the year and nohealth hazard had been reported during normalkiln operations. Therefore, the health hazardevaluation was placed on hold until the nextscheduled maintenance period. NIOSH wasnotified on November 21, 1996, that the kilnwould be shut down for repair from December 2until December 5, 1996. This report describes theresults of the survey that was conducted duringthis period.

The original cement plant was built at UnionBridge, Maryland, in 1910. The plant waspurchased by Lehigh Portland Cement Companyin December 1925, completely modernized in1939, and again in 1957.1 The secondmodernization more than tripled the size of theplant, increasing its annual production capacity to660,000 tons. Three of the kilns built at this timeare currently operating. In 1970, during a thirdmodernization and rebuilding period, a fourth kilnwas constructed, increasing the plant’s productioncapacity to 900,000 tons per year. Thechlorine–like odor and respiratory irritation haveonly been associated with the fourth kiln, whichhas a dust control system separate from the threeolder kilns.

BACKGROUNDPortland cement is produced by heating oxides ofcalcium, silicon, aluminum, and iron in variouscombinations, up to 2700°F in a rotating kiln to

form calcium–aluminum silicates.2 The principalraw materials used at the Union Bridge plant —limestone and shale which provide the calciumand aluminum sources — are obtained from aquarry near the plant; sand — the silicon source,and mill scale — the iron source, are purchasedfrom other companies. No chlorine–containingcompounds are used in manufacturing Portlandcement.

Two methods are used for manufacturing Portlandcement: (1) the dry process in which the rawmaterials are mixed, ground, and transported intothe kiln as a dry powder; and (2) the wet processin which the raw materials are mixed, ground, andtransported into the kiln as a fluid slurry. The dryprocess is used at the Union Bridge plant. Thefour rotary kilns are basically 3/4 inches thickwelded–steel tubes, 11.5 feet in diameter and 400feet in length, lined with high–temperaturerefractory bricks 6 to 9 inches thick. No mortars,binders, or coatings are used on the bricks. Thekilns rotate on a slightly inclined axis, 80 to 90revolutions per hour. The raw materials enter thekiln through a screw feeder at the upper end of thekiln (feed–end or back–end). The materials areheated to progressively higher temperatures untilthey leave the lower end of the kiln( d i s c h a r g e – e n d o r f r o n t – e n d ) a scalcium–aluminum silicate clinkers. Clinkers arehard, dark, glossy nodules of Portland cement.

The clinkers are dropped from the front–end ofthe kilns, cooled by blowing air, and thenconveyed to a storage area. The clinkers aremixed using varying amounts of gypsum(hydrated calcium sulfate) to control the rate atwhich the cement hardens. The mixture is thenground into a fine powder in rotating ball mills toproduce the finished product, Portland cement.Portland cement is then shipped in packages or asbulk in trucks or railcars.

At the Lehigh plant, pulverized coal is the primaryfuel source, and scrap tires are used as asupplemental fuel source. Pulverized coal isblown into the front end of the kilns, inducing

Health Hazard Evaluation Report No. HETA 96–0226 Page 3

temperatures higher than the melting point ofsteel. Tires are automatically dropped into themiddle of the kilns, one tire per revolution. Thepractice of burning scrap tires was begun duringthe summer of 1995. At one time waste oils fromrefineries were also used as a supplemental fuelsource, but this practice was stopped in 1994.

Dust pollution control is an important aspect ofkiln operation. Induced draft (ID) fans draw thewaste gases from the kilns through electrostaticprecipitators to remove dust particles. Theremaining gases are then vented out the stacks.The three kilns which began operation in 1957share a common exhaust system and stack. Thefourth kiln which began operation in 1970 wasinstalled with a separate exhaust system and stack.In 1992 the height of the exhaust stacks wasincreased due to excessive sulfur dioxideexposures from the combustion of coal in thekilns. Since that time no further problems withexcessive sulfur dioxide exposures have beenreported inside the plant.

The first occurrence of respiratory problemsassociated with the repair of kiln #4 was on March19, 1993. Nine workers were replacing refractorybricks approximately 20 to 30 feet from the frontend of the kiln; two were on a scaffold layingbricks in the top of the kiln, two were layingbricks in the bottom of the kiln, two wereremoving bricks from a conveyor and handingthem to the bricklayers, two were placing brickson the conveyor just outside the front of the kiln,and a forklift operator transported pallets of bricksto a position near the conveyor. The ID fan hadbeen turned off at 5:00 a.m. because the nightcrew, who had been replacing bricks, complainedof cold air drafts. The nine dayshift workers hadbegun replacing bricks at 7:00 a.m. By 7:20 a.m.,one of the workers who was laying bricks in thebottom of the kiln reported a severe cough,headache, profuse perspiration, nausea andfatigue. The worker stated that while he was inthe kiln, he noticed a chlorine, bleach–like odor.Other workers reported that they had detected asimilar odor emanating from the worker’s clothes.

Subsequently, the symptomatic worker was takento the hospital for evaluation. The remaining fiveworkers who were inside the kiln also noticed thechlorine–like odor and reported coughing,headaches, sore throats, and shortness of breath,but their symptoms were not as severe. The threeworkers who were working outside the kilnnoticed the chlorine odor but did not experienceany symptoms. The ID fan was turned back on at7:30 a.m. Soon the chlorine odor was gone andthe workers were able to complete the rebrickingoperation.

The second occurrence of respiratory problemsassociated with the repair of kiln #4 was onFebruary 11, 1996. The kiln was shut down at4:45 a.m. when the kiln feed hopper had becomeclogged with wet raw materials due to a waterspray problem at the back end of the kiln. At11:30 a.m., two workers entered the back end ofthe kiln to loosen the clogged material using ironbars. These workers left the plant at 3:00 p.m.and did not report any odor or respiratorysymptoms associated with their work. However,two replacement workers reported that theyimmediately detected a chlorine odor uponentering the kiln. A third worker joined the tworeplacement workers at 7:30 p.m. At the end oftheir workshift (9:00 p.m.), all three workersreported they had smelled a bleach–like odor andreported symptoms of cough, tightness in thechest, and burning eyes. Subsequently, no oneentered the kiln until four, third shift workersentered at 11:30 p.m. Within a few minutes ofentering the kiln all four workers reported a strongchlorine odor with subsequent symptoms ofcough, chest tightness, nausea, and burning eyesand nose. It is not clear at what time the ID fanwas turned off, but it was not operating at 11:30p.m. when the four workers entered the kiln.However, when the fan was turned on, conditionsbecame so dusty that the workers lost visibility.The workers left the kiln for 15 minutes to allowthe fan to remove the odor, the fan was thenturned off, the workers re–entered the kiln, andthe odor and the workers’ symptoms quicklyreturned. All the workers then exited the kiln and


the unclogging operation was completed byworkers standing outside the kiln.

METHODSNIOSH was requested to monitor workerexposures when kiln #4 was shut down forscheduled maintenance. On December 3, 1996,workers entered the kiln to replace the first 25 feetof refractory brick at the front–end of kiln #4.Symptoms experienced by workers duringprevious maintenance operations suggested thatthey were exposed to irritant gases or dusts.Although the workers reported a chlorine,bleach–like odor, the raw materials for clinkerproduction do not contain chlorine compoundsand chlorine is not used in any aspect of kilnoperations. However, chlorine (chlorides)measurements were collected to evaluate thepossibility of chlorine being the cause of thereported respiratory symptoms. Air samples werealso collected to measure concentrations of sulfurdioxide, oxides of nitrogen, ozone, and inorganicacid inside the kiln.

Sulfur dioxide and oxides of nitrogen are commonby–products of coal combustion, and cause eyeand upper respiratory irritation. Ozone is formedfrom high electrical voltage discharge inelectrostatic precipitators, and has been shown tocause irritation of the eyes and mucousmembranes. These gases were suspected to bepresent during kiln operation. Residual gasconcentrations due to back–draft from the kilnexhaust system could result when the kiln wasshut down for maintenance. Inorganic acids werenot suspected of being present during kilnoperation or maintenance, but were sampled toevaluate chlorine acid vapors as a potential causeof the workers’ symptoms.

Respirable, total, and inhalable dust samples werealso collected. Portland cement dust causesdermatitis and may be irritating to the eyes andnose due its alkaline, hygroscopic, and abrasiveproperties.3 Portland cement has not been

documented to cause pneumoconiosis, butcrystalline silica (quartz and cristobalite), whichcauses silicosis, may be present in the rawmaterials used to manufacture Portland cement.Respirable dust samples, which evaluate dustexposures for the alveolar and lower airways ofthe lungs, were analyzed for crystalline silica toevaluate workers’ potential risk for silicosis.Total dust samples were analyzed for arsenic,cadmium, copper, chromium, magnesium, nickel,and zinc content; these selected metals have beendocumented to affect the respiratory system(please see Evaluation Criteria Section).

Personal breathing zone (PBZ) samples werecollected for chlorine, sulfur dioxide, andrespirable and total dust by attaching samplingmedia to the collars of workers involved in there–bricking operation. Area samples werecollected for chlorine, inorganic acid, sulfurdioxide, oxides of nitrogen, respirable, total, andinhalable dusts at three sampling station locationsinside the kiln. The area samples were collectedby attaching sampling media to tri–podspositioned near the front, middle, and rear of thekiln. Table 1 summarizes all of the air samplingmethods used in this evaluation.

EVALUATION CRITERIAAs a guide to the evaluation of the hazards posedby workplace exposures, NIOSH field staffemploy environmental evaluation criteria for theassessment of a number of chemical and physicalagents. These criteria are intended to suggestlevels of exposure to which most workers may beexposed up to 10 hours per day, 40 hours perweek for a working lifetime without experiencingadverse health effects. It is, however, important tonote that not all workers will be protected fromadverse health effects even though their exposuresare maintained below these levels. A smallpercentage may experience adverse health effectsbecause of individual susceptibility, a pre-existingmedical condition, and/or a hypersensitivity(allergy). In addition, some hazardous substances


may act in combination with other workplaceexposures, the general environment, or withmedications or personal habits of the worker toproduce health effects even if the occupationalexposures are controlled at the level set by thecriterion. These combined effects are often notconsidered in the evaluation criteria. Also, somesubstances are absorbed by direct contact with theskin and mucous membranes, and thus potentiallyincrease the overall exposure. Finally, evaluationcriteria may change over the years as newinformation on the toxic effects of an agentbecome available.

The primary sources of environmental evaluationcriteria for the workplace are: (1) NIOSHRecommended Exposure Limits (RELs),4 (2) theAmerican Conference of Governmental IndustrialHygienists' (ACGIH) Threshold Limit Values(TLVs™),5 and (3) the U.S. Department of Labor,OSHA Permissible Exposure Limits (PELs).6In July 1992, the 11th Circuit Court of Appealsvacated the 1989 OSHA PEL Air ContaminantsStandard. OSHA is currently enforcing the 1971standards which are listed as transitional values inthe current Code of Federal Regulations; however,some states operating their own OSHA approvedjob safety and health programs continue toenforce the 1989 limits. NIOSH encouragesemployers to follow the 1989 OSHA limits, theNIOSH RELs, the ACGIH TLVs, or whicheverare the more protective criterion. The OSHAPELs reflect the feasibility of controllingexposures in various industries where the agentsare used, whereas NIOSH RELs are basedprimarily on concerns relating to the prevention ofoccupational disease. It should be noted whenreviewing this report that employers are legallyrequired to meet those levels specified by anOSHA standard and that the OSHA PELsincluded in this report reflect the 1971 values.

A time–weighted average (TWA) exposure refersto the average airborne concentration of asubstance during a normal 8– to 10–hourworkday. Some substances have recommendedshort–term exposure limits (STEL) or ceiling

values which are intended to supplement theTWA where there are recognized toxic effectsfrom higher exposures over the short–term. Theimmediately dangerous to life or health (IDLH)concentration is considered the maximumconcentration above which only a highly reliablebreathing apparatus providing maximum workerprotection is permitted. The purpose of the IDLHis to ensure that workers can escape withoutinjury or irreversible health effects from an IDLHexposure in the event of the failure of respiratoryprotection equipment.

OzoneOzone is a blue gas. The gas possesses acharacteristic odor in concentrations of less than2 ppm. Ozone is used as a disinfectant for air andwater; for bleaching textiles, oils, and waxes; andin organic syntheses. It is also produced inwelding arcs and corona discharges and byultraviolet radiation.7

Ozone is an irritant of the mucous membranes andthe lungs. The primary target of ozone is therespiratory tract. Symptoms range from nose andthroat irritation to cough, dyspnea, and chest pain.The toxic effects of ozone can be attributed to itsstrong oxidative capacity. Specifically, ozonemay act by initiating peroxidation ofpolyunsaturated fatty acid present in the cellmembrane or by direct oxidation of amino acidsand proteins also found in the membranes. Ifdamage is severe, the cell dies; necrosiscommonly is reported in the lungs of heavilyexposed animals. In animal studies, acharacteristic ozone lesion occurs at the junctionof the conducting airways and the gas–exchangeregion of the lung following acute exposure. Thisanatomical site is probably affected in humans aswell.8

The NIOSH REL is 0.1 ppm to be measured as a15–minute ceiling concentration.4 NIOSH hasalso recommended an IDLH of 10 ppm for ozone.9

The current OSHA PEL for ozone is 0.1 ppm asan 8–hour TWA, and 0.3 ppm as a 15–minute


ceiling concentration.6 The current ACGIH TLVis also 0.1 ppm to be measured as a 15–minuteceiling concentration. However, the ACGIH hasissued a notice of intended change. The proposedACGIH TLV is based on amount of physicalexertion or work load required for the job beingaccomplished and is to be average over an 8–hourperiod. The proposed TLV is 0.1 ppm for jobsrequiring light physical exertion, for a moderatephysical exertion the TLV is lowered to 0.08 ppm,and for a heavy physical exertion the TLV islowered to 0.05 ppm.5

ChlorineChlorine is a greenish–yellow gas with a verypungent odor. It is slightly soluble in water,forming hydrochloric acid. Chlorine reacts withmoisture in the eyes and respiratory airways toform acids. It is extremely irritating to the skin,eyes, and mucous membranes. Chlorine in highconcentrations acts as an asphyxiant by causingcramps in the muscles of the trachea, swelling ofthe mucous membranes, nausea, vomiting, andanxiety. Acute respiratory distress includingcough, blood in sputum, chest pain, dyspnea, andtracheobronchitis, pulmonary edema, andpneumonia occurs with exposure to excessiveconcentrations.

The NIOSH REL is 0.5 ppm to be measured as a15–minute ceiling concentration.4 NIOSH hasalso recommended an IDLH of 10 ppm for ozone.9

The current OSHA PEL for chlorine is 1.0 ppm asa ceiling concentration.6 The current ACGIHTLV is 0.5 ppm as an 8–hour TWA and 1.0 ppmas a 15–minute ceiling concentration.5

Sulfur DioxideSulfur dioxide is intensely irritating to the eyes,mucous membranes, and respiratory tract. It cancause burning of the eyes and tearing, coughing,and chest tightness. Exposure may cause severebreathing difficulties. It forms sulfurous acid oncontact with moist membranes.8 Chronic

exposure may result in nasopharyngitis, fatigue,altered sense of smell, and chronic bronchitissymptoms such as dyspnea on exertion, cough,and increased mucous excretion. Someindividuals have become sensitized followingrepeated exposures. NIOSH, OSHA, and ACGIHhave set a TWA exposure limit of 2 ppm (5.2milligrams per cubic meter [mg/m3]) for sulfurdioxide, and a 5 ppm (13 mg/m3) short–termexposure limit.

Particulates, Not OtherwiseClassifiedOften the chemical composition of the airborneparticulate does not have an establishedoccupational health exposure criterion. It hasbeen the convention to apply a generic exposurecriterion in such cases. Formerly referred to asnuisance dust, the preferred terminology for thenon–specific particulate ACGIH TLV criterion isnow "particulates, not otherwise classified(n.o.c.)," [or "not otherwise regulated" (n.o.r.) forthe OSHA PEL]. In comments to OSHA onAugust 1, 1988, on their “Proposed Rule on AirContaminants,” NIOSH questioned whether theproposed PEL for PNOR (10 mg/m3) wasadequate to protect workers from recognizedhealth hazards.

Particulates not otherwise regulated (nuisancedusts) have a long history of little adverse effecton lungs and do not produce significant organicdisease or toxic effect when exposures are keptunder reasonable control. Portland cement dustsare considered in this category. The lung tissuereaction caused by inhalation of nuisance dustshas the following characteristics: (1) thearchitecture of the air spaces remains intact; (2)scar tissue is not formed to a significant extent;and (3) the tissue reaction is potentiallyreversible.7 Respirable particulate refers tomaterials that are able to reach the gas–exchangeregion of the lung.


The current OSHA PEL for particulates nototherwise regulated is 15 mg/m3 for total dust and5 mg/m3 for the respirable portion, measured as an8–hour TWA.6 The ACGIH TLV for particulatesnot otherwise classified is 10 mg/m3 for inhalableparticulate and 3 mg/m3 for respirable particulate.5These criteria were established to minimizemechanical irritation of the eyes and nasalpassages, and to prevent visual interference.These are generic criteria for airborne dusts whichdo not produce significant organic disease or toxiceffect when exposures are kept under reasonablecontrol.5 These criteria are not appropriate fordusts that have a biologic effect.

Silica (amorphous, quartz,cristobalite)Amorphous silica does not have a crystallinelattice molecular configuration. Historicalevaluations of amorphous silica suggest that it isof low toxicity, and it has not been reported toproduce fibrotic nodules in lung tissue(characteristic of crystalline silica exposure).8,10

The NIOSH REL for exposure to amorphoussilica is a full–shift, total particulate TWA of6 mg/m3, providing the silica contains less than1% crystalline forms.9 The OSHA PEL is80 mg/m3 divided by the %SiO2, as an 8–hourTWA. The ACGIH TLV for amorphous silicacontaining less than 1% crystalline silica is10 mg/m3 for inhalable particulate as an 8–hourTWA, and 3 mg/m3 for respirable particulate as an8–hour TWA.

Crystalline silica (quartz) and cristobalite havebeen associated with silicosis, a fibrotic disease ofthe lung caused by the deposition of fine particlesof crystalline silica in the lungs. Symptomsusually develop insidiously, with cough, shortnessof breath, chest pain, weakness, wheezing, andnon–specific chest illnesses. Silicosis usuallyoccurs after years of exposure, but may appear ina shorter period of time if exposure concentrationsare very high. The NIOSH RELs for respirablequartz and cristobalite are 50 micrograms per

cubic meter (:g/m3), as TWAs, for up to 10 hoursper day during a 40–hour work week.4 TheseRELs are intended to prevent silicosis. However,evidence indicates that crystalline silica is apotential occupational carcinogen and NIOSH isc u r r e n t l y r e v i e w i n g t h e d a t a o ncarcinogenicity.11,12,13,14 The OSHA PELs forrespirable quartz is 10 mg/m3 divided by the value“%SiO2+2,” the PEL for cristobalite is ½ thecalculated value for quartz.9 The ACGIH TLVsfor respirable quartz and cristobalite are 100 and50 :g/m3, as 8–hour TWAs, respectively.

MetalsChromium (Cr) exists in a variety of chemicalforms and its toxicity varies among the differentforms. For example, elemental chromium isrelatively non–toxic. Other chromium compoundsmay cause skin irritation, sensitization, andallergic dermatitis. In the hexavalent form[Cr(VI)], Cr compounds are corrosive, andpossibly carcinogenic.8 Until recently, the lesswater–soluble Cr(VI) forms were consideredcarcinogenic while the water–soluble forms werenot considered carcinogenic. Recentep idemi o l ogi ca l ev idence ind i ca t e scarcinogenicity among workers exposed to solubleCr(VI) compounds. Based on this new evidence,NIOSH recommends that all Cr(VI) compoundsbe considered as potential carcinogens.4 TheNIOSH REL and the ACGIH TLV for chromiummetal is 0.5 mg/m3, and the OSHA PEL is 1mg/m3 for chromium metal.4,5,6

Inhalation of copper fume has resulted inirritation of the upper respiratory tract, metallictaste in the mouth, and nausea.8 Exposure hasbeen associated with the development of metalfume fever.4 The NIOSH REL, the ACGIH TLV,and the OSHA PEL for copper dust is 1 mg/m3 asa TWA.4,5,6

Magnesium can cause eye and nasal irritation.Exposure has been associated with thedevelopment of metal fume fever.4 NIOSH didnot agree with OSHAs proposed rule for


magnesium and did not adopt an REL for thissubstance, the ACGIH TLV and the OSHA PELis 10 mg/m3 as an 8–hour TWA.4,5,6

Zinc has been associated with shortness of breath,minor lung function changes, and metal fumefever.4 The NIOSH REL for zinc oxide fume andzinc oxide as total dust is 5 mg/m3, the ACGIHrecommends a TLV of 5 mg/m3 for zinc oxidefume and 10 mg/m3 for zinc dust, and the OSHAPEL is 5 mg/m3 for zinc oxide fume, 10 mg/m3 astotal dust and 5 mg/m3 as respirable dust.4,5,6

RESULTSOn December 2, 1996, at 7:00 p.m., kiln #4 wasshut down for removal and replacement ofrefractory bricks from the first 25 feet of the lowerend of the kiln. Kilns #1, #2, and #3 continued tooperate during this maintenance operation. OnDecember 3, at 7:00 a.m., the kiln was coolenough for workers to begin removing a coatingof hard fused rock material and old refractorybricks from the interior of the kiln. By thatevening, the removal portion of the operation hadbeen completed. Repair crews then workedaround the clock to complete the rebrickingoperation by midnight on December 4. By 2:00a.m. on December 5, the scheduled maintenancehad been completed and all workers had exited thekiln. Dust and gas samples were then placed inthe middle and at the back end of the kiln. Thenkiln conditions under which workers hadexperienced respiratory symptoms on February11, 1996, were re–created (i.e., the ID fan wasturned off and the electrostatic precipitator wasoperated at half capacity). During this experimentworkers were not allowed inside the kiln.

The results of PBZ air samples collected fromworkers performing the removal and rebrickingtasks are presented in Table 2. Dust exposureswere somewhat higher while workers wereremoving coating and bricks from the kiln;however, none of the PBZ dust measurementsexceeded current exposure criteria. Chlorine was

not detected on the PBZ air samples and onlytrace quantities of sulfur dioxide were detected.

The results of the dust measurements collected atarea sampling stations inside the kiln arepresented in Table 3. None of these area dustsamples exceeded current exposure criteria. Theaverage total and inhalable dust measurementswere similar, but the respirable samples wereapproximately 80% to 90% lower than the totaldust measurements indicating that most of theinhaled airborne dust would be deposited in thenose, throat, and upper airways, rather than thealveoli and lower airways. The inconsistenciesbetween the total and inhalable dustconcentrations reported may be due to samplervariabilities.

Quartz and cristobalite were not detected in any ofthe PBZ or area respirable dust samples.However, quartz was detected in three bulk dustsamples collected at the front end of the kiln, atthe middle of the kiln, and at the back end of thekiln in concentrations of 2.3%, 3.5%, and 2.6%,respectively. Cristobalite was not detected in anyof these samples. Concentrations of cadmium,chromium, copper, magnesium, nickel, and zincfound in the PBZ total dust samples, area totaldust samples, and bulk dust samples are presentedin Table 4. Arsenic was not detected in any ofthese samples. Only one area air sample collectedat the back end of the kiln contained detectablequantities of cadmium and nickel. None of theconcentrations detected in the air samplesexceeded current exposure criteria. Magnesiumwas the only metal detected in the bulk samples inmore than trace quantities. Hexavalent chromium,which has been reported to cause allergicdermatitis due to sensitization of the skin, wasdetected in bulk samples collected at the front, themiddle, and the back of the kiln in concentrationsof 16, 12, and 49 :g/gm, respectively.

Chlorine was not detected inside the kiln usingeither the silver membrane filters or thedirect–reading color indicator tubes. Also,inorganic acids were not detected inside the kiln.


A trace quantity of sulfur dioxide was detected inone area sample, collected at the back end of thekiln between 3:52 a.m. and 8:15 a.m., onDecember 5 (17.98 :g/m3 = 0.007 ppm). Ozonewas not detectable using either the direct–readingcolor indicator tubes or the Metrosonic Toxic GasMonitor direct–reading monitor at any locationwhile workers were inside the kiln. Due toanalytical laboratory error the results of the oxidesof nitrogen samples could not be accuratelydetermined.

After all workers had exited the kiln, samplingequipment for total dust, inhalable dust, respirabledust, and metals, was placed inside between 3:30and 4:00 a.m. on December 5, and at 4:01 a.m. theID fan was turned off. The electrostaticprecipitator serving kiln #4 was reduced to halfstrength, with the east precipitator unit turned onand the west precipitator unit turned off. Between4:30 and 5:00 a.m., workers who were working onthe kiln floor near the front of kiln #4 reported afaint odor resembling the odor they had smelledwhen workers experienced respiratory symptomson February 11, 1996; the odor was described asa chlorine or bleach–like. The odor wasdistinctive, but intermittent. At 6:45 a.m. theNIOSH investigator began taking chlorinemeasurements using direct–reading color indicatortubes and ozone measurements usingdirect–reading color indicator tubes and theMetrosonic Toxic Gas Monitor direct–readingmeter near the front and back ends of kiln #4.Chlorine was not detected on two color indicatortubes collected at the front of the kiln. However,a reading of 0.6 to 0.7 ppm ozone was detected ontwo ozone color indicator tubes and a reading of0.09 to 0.11 ppm ozone was detected using theMetrosonic monitor at the front end of the kiln.Background readings collected with theMetrosonic monitor in the plant yard yielded 0.02to 0.03 ppm.

At 7:15 a.m., investigators collected chlorine andozone measurements through a portal at the backend of the kiln. Chlorine was not detected usinga color indicator tube, but two pump strokes on an

ozone indicator tube saturated the tube. (Theozone color indicator tube is calibrated to detectozone concentrations between 0.05 and 0.7 ppmwith +25% accuracy using ten strokes of ahand–held air pump.) This measurementindicated that the ozone concentrations inside thekiln were well above 0.7 ppm. The Metrosonicdirect– reading meter detected a concentration of4.5 ppm, and the reading remained stable forseveral minutes. The hands and sleeves of theinvestigator who took the measurements throughthe portal had a strong, pungent chlorine orbleach–like odor. Several workers stated that theodor on the investigator’s hands and clothing wasidentical to the odor they had smelled during thetwo previous respiratory irritation episodes.

At 7:40 a.m., the electrostatic precipitator wasturned off and the ID fan was turned on. By7:50 a.m. the ozone concentration detected usingthe Metrosonic direct–reading meter had droppedto between 0.16 to 0.17 ppm. Within onehalf–hour after the ID fan was turned on and theprecipitator was turned off, the Metrosonic meterreadings had decreased to background levels. Asummary of the ozone measurements is presentedin Table 5.

DISCUSSIONThe measurements collected during the kiln repairoperations at the Lehigh Portland cement plantbetween December 3 and December 5, 1996,support the conclusion that the previousoccurrences of eye and upper respiratory irritationwere caused by exposure to ozone and notchlorine compounds. The source of the ozone wasthe electrostatic precipitator. When the ID kilnexhaust fan had been turned off while theprecipitator continued to operate, ozoneback–drafted from the precipitator into the kilnarea. Measurements indicated that the ozoneconcentrations may have approached 5 ppm, wellabove existing exposure criteria.


1. Booklet describing the Lehigh PortlandCement Plant at Union Bridge, Maryland. LehighPortland Cement Company, Allentown,Pennsylvania.

2. Shreve RN, Brink JA [1977]. ChemicalProcess Industries. New York, NY: McGraw–HillBook Company.

3. NIOSH [1977]. Occupational Diseases: AGuide to their Recognition. Cincinnati, OH: U.S.Department of Health, Education, and Welfare,Public Health Service, Centers for DiseaseControl, National Institute for OccupationalSafety and Health, DHEW (NIOSH) PublicationNo. 77–181.

4. NIOSH [1992]. Recommendations foroccupational safety and health: compendium ofpolicy documents and statements. Cincinnati,OH: U.S. Department of Health and HumanServices, Public Health Service, Centers forDisease Control, National Institute forOccupational Safety and Health, DHHS (NIOSH)Publication No. 92–100.

Sulfur dioxide was only detected in traceconcentrations and was unlikely to havecontributed to the irritation outbreaks. Airbornedust levels and quartz and metals concentrationsdid not indicate that workers were at increasedrisk for pneumoconiosis (silicosis) or othersignificant pulmonary effects. However, whileworking inside the kiln the wearing of personalrespirators can reduce concentrations of inhaleddust particles which may dry and irritate nasalpassages and upper airways. The irritationoutbreaks were not temporally associated with theburning of used tires or waste oils, so combustionproducts from these materials probably did notcause the irritation symptoms. Chlorine was notdetected at any of the sample locations and is notused in the production of Portland cement. Thedistinctive chlorine–like odor and the irritationsymptoms experienced by workers on previousoccasions was clearly caused by ozone from theelectrostatic precipitators.

CONCLUSIONSThe chlorine–like odor and respiratory and eyeirritation symptoms that workers experiencedwhen repairing kiln #4, were caused by ozone.Ozone back–drafted into the kiln from theelectrostatic precipitator when the precipitatorwas operating and the induced draft (ID) fan wasturned off. The ozone concentrations inside thekiln during previous maintenance operations mayhave approached 5 ppm, 50 times the NIOSHceiling REL. Ozone is a potent irritant to the eyesand all mucous membranes.15 Symptomsfollowing acute exposure to ozone includecoughing, chest tightness, burning eyes, headache,and severe fatigue. Pulmonary edema may occur,sometimes several hours after exposure hasceased.

Chlorine was not detected inside the kiln.Concentrations of sulfur dioxide detected insidethe kiln were well below established criteria andwould not cause eye and respiratory irritation.Dust measurements did not indicate that workersperforming maintenance inside the kiln wereexposed to excessive concentrations of dust,crystalline silica, or metals.

RECOMMENDATIONSBefore workers enter the kiln, the electrostaticprecipitator should be turned off and the ID fanshould continue to operate. If the ID fan has to beturned off, the precipitator should remain off andthe fan should be run for several minutes toremove residual ozone before workers enter thekiln. While workers are inside the kiln, the ozonelevels should be periodically monitored.

Workers should be warned of the symptoms ofexcessive exposure to ozone. If they begin toexperience these symptoms, they should exit thearea (kiln) and report their symptoms to theirsupervisor and plant health and safety staff.

REFERENCES


5. ACGIH [1996]. 1996 TLVs® and BEIs® thres-hold limit values for chemical substances andphysical agents and biological exposure indices.Cincinnati, OH: American Conference ofGovernmental Industrial Hygienists.

6. Code of Federal Regulations [1993]. 29 CFR1910.1000. Washington, DC: U.S. GovernmentPrinting Office, Federal Register.

7. ACGIH [1991]. Documentation of thethreshold limit values and biological exposureindices. 6th ed. Cincinnati, OH: AmericanConference of Governmental IndustrialHygienists, with supplements through 1994.

8. Hathaway GJ, Proctor NH, Hughes JP, andFischman MJ [1991]. Proctor and Hughes'Chemical Hazards of the Workplace. 3rd. ed.New York, NY: Van Nostrand Reinhold.

9. NIOSH [1994]. Pocket Guide to ChemicalHazards. Cincinnati, Ohio: U.S. Department ofHealth and Human Services, Public HealthService, Centers for Disease Control andPrevention, National Institute for OccupationalSafety and Health, DHHS (NIOSH) PublicationNo. 94–116.

10. NIOSH [1986]. Occupational respiratorydiseases. Cincinnati, OH: U.S. Department ofHealth and Human Services, Public HealthService, Centers for Disease Control, NationalInstitute for Occupational Safety and Health,DHHS (NIOSH) Publication No. 86–102.

11. NIOSH [1974]. Abrasive blasting respiratoryprotective practices. Washington, DC: U.S.Department of Health, Education, and Welfare,Public Health Service, Center for Disease Control,National Institute for Occupational Safety andHealth, DHEW (NIOSH) Publication No. 74–104,p 106.

12. IARC [1987]. IARC monograms on theevaluation of carcinogenic risk of chemicals tohumans: silica and some silicates. Vol 42. Lyons,France: World Health Organization, International

Agency for Research on Cancer, pp 49,51,73–111.

13. NIOSH [1988]. NIOSH testimony to the U.S.Department of Labor: statement of the NationalInstitute for Occupational Safety and Health.Presented at the public hearing on OSHAPELs/crystalline silica, July 1988. NIOSH policystatements. Cincinnati, OH: U.S. Department ofHealth and Human Services, Public HealthService, Centers for Disease Control, NationalInstitute for Occupational Safety and Health.

14. DHHS [1991]. Sixth annual report oncarcinogens: summary 1991. Research TrianglePark, NC: U.S. Department of Health and HumanServices, Public Health Service, National Institutefor Environmental Health Sciences, pp 357–364.

15. Lippman M [1989]. Health effects of ozone:a critical review. Journal Air Pollution ControlAssociation 39:672–695.


Table 1 (Page 1 of 2)Summary of Sampling and Analytical Methods

Lehigh Portland Cement CompanyUnion Bridge, Maryland

HETA 96–0226

Substance Flow Rate(Lpm)

Sample Media Analytical Method Analytical Limit ofDetection (LOD) per

Sample

Chlorine1.0 PTFE prefilter (25 mm diameter, 0.5 :m

pore size) followed by silver membranefilter (25 mm diameter, 0.45 :m poresize)

NIOSH Method No. 60111 :g

0.02 Dräger™ color indicator tube Color reaction with solidsorbent material 0.1 ppm

Sulfur Dioxide 1.0 Cellulose ester membrane filter (37 mmdiameter, 0.8 :m pore size) followed bya sodium carbonate–treated celluloseester filter

NIOSH Method No. 60040.5 :g

Oxides of Nitrogen 0.025 Two triethanolamine–treated molecularsieve sorbent tubes with oxidizer tubeplaced in between

NIOSH Method No. 60141 :g

OzoneNA Metrosonic pm–7000 toxic gas monitor Electrochemical sensor 0.02 ppm

Hand–heldbellows pump

Dräger™ color indicator tube Color reaction with solidsorbent material 0.05 ppm

Inorganic Acid 0.5 Silica gel in a sorbent tube NIOSH Method No. 7903,Acids, inorganic 3 :g

Table 1 (Page 2 of 2)Summary of Sampling and Analytical Methods


HETA 96–0226

Substance Flow Rate(Lpm)

Sample Media Analytical Method Analytical Limit ofDetection (LOD) per

Sample


Respirable Particulate andCrystalline Silica

1.7 Tared PVC filter (37 mm diameter,0.8 :m pore size)

NIOSH Method No. 0500, Gravimetric analysisNIOSH Method No. 7500,Quartz and cristobaliteanalysis

10 :g gravimetric10 :g quartz

20 :g cristobalite

Total Particulate andMetals (As, Cd, Cu, Cr,Mg, Ni, Zn)

2.0 Tared PVC filter (37 mm diameter,0.8 :m pore size)

NIOSH Method No. 0500,Gravimetric analysisNIOSH Method No. 7300, Trace metal analysis

10 :g gravimetric3 :g arsenic

0.008 :g cadmium0.5 :g chromium0.08 :g copper

0.5 :g magnesium0.5 :g nickel0.5 :g zinc

Inhalable Particulate 1.0 Tared PVC filters in an IOMcassette

Filters were pre–weighedand post–sampling weighedon a Mettler A–20 balance. The difference between theinitial and final weightsyielded total weight.

20 :g


Table 2Personal–breathing–zone Air Samples Collected

During Maintenance on Kiln #4Lehigh Portland Cement Company

Union Bridge, MarylandHETA 96–0226

Type of Sample Time Sample Collected Concentrationmg/m3

December 3, 1996 – Workers Removing Coating and Old Bricks from First 25 feet of Kiln #4

Total Dust 11:04 a.m. – 6:36 p.m. 3.75

Respirable Dust 11:04 a.m. – 6:36 p.m. 0.41

Chlorine 10:56 a.m. – 6:38 p.m. ND

Sulfur Dioxide 10:56 a.m. – 6:38 p.m. Trace

December 4, 1996 – Workers Rebricking First 25 feet of Kiln #4

Total Dust 7:32 a.m. – 3:45 p.m. 1.24

Respirable Dust 7:32 a.m. – 3:45 p.m. 0.13

Chlorine 7:41 a.m. – 4:50 p.m. ND

Sulfur Dioxide 7:41 a.m. – 4:50 p.m. Trace

Abbreviations:ND – nondetectableTrace – quantity detected is between the analytical limit of detection and the analytical limit ofquantitation


Table 3Area Air Samples for Dust Collected at Locations Inside Kiln #4


HETA 96–0226

Location/OperationID

Fan Date TimeTotal Dust

Concentrationmg/m3

Inhalable DustConcentration

mg/m3

Respirable DustConcentration

mg/m3

27 ft inside front of kiln; workersremoving coating and old bricks from first25 ft of front of kiln

On 12/3/96 11:46 a.m. – 12:42p.m.

4:54 p.m. – 9:01 p.m.

0.84 0.88 0.10

5 ft uphill from chains in back end of kiln;workers removing coating and old bricksfrom first 25 ft of front end of kiln

On 12/3/96 5:42 p.m. – 9:26 p.m. 0.54 1.13 0.10

5 ft uphill from chains in back end of kiln;workers rebricking first 25 ft of front endof kiln

On 12/4/96 8:26 a.m. – 5:13 p.m. 2.67 0.93 0.21

30 ft uphill from tire door near middle ofkiln; no workers inside kiln

Off 12/5/96 3:43 a.m. – 8:25 a.m. 0.67 0.70 0.15

5 ft uphill from chains in back end of kiln;no workers inside kiln

Off 12/5/96 3:52 a.m. – 8:15 a.m. 0.96 1.49 0.20


Table 4Concentrations of Selected Metals from Personal and Area Total Air Filter Samples and Bulk Dust Samples


HETA 96–0226

Personal and Area Air Filter Samples Date TimeMetals Concentrations in Air Filter Samples (::::g/m3)

Cd Cr Cu Mg Ni Zn

Personal: Worker removing coating andold bricks from first 25 ft of kiln #4

12/3/96 11:04 a.m. – 6:36 p.m. <LOD 1.0 0.49 175 <LOD 3.6

Personal: Worker rebricking first 25 ft ofkiln #4

12/4/96 7:32 a.m. – 3:45 p.m. <LOD 0.82 0.62 143 <LOD 2.1

Area: 27 ft inside front of kiln 12/3/96 11:46 a.m. – 12:42p.m.

4:54 p.m. – 9:01 p.m.

<LOD <LOD 0.36 35 <LOD 3.0

Area: 5 ft uphill from chains in back endof kiln

12/3/96 5:42 p.m. – 9:26 p.m. <LOD <LOD 0.45 13 <LOD 2.7


12/4/96 8:26 a.m. – 5:13 p.m. 0.09 6.3 0.58 122 2.4 2.3

Area: 30 ft uphill from tire door nearmiddle of kiln

12/5/96 3:43 a.m. – 8:25 a.m. <LOD <LOD <LOD 17 <LOD 3.4


12/5/96 3:52 a.m. – 8:15 a.m. <LOD <LOD <LOD 13 <LOD 2.8

Bulk Dust Samples Collected from Locations Inside Kiln Metals Concentrations in Bulk Dust Samples (::::g/gm)

Bulk: Front end of kiln 3.4 39 16 14,000 14 120

Bulk: Middle of kiln near tire insert door 8.6 270 19 15,000 21 120

Bulk: Back end of kiln near start of chains 17.0 740 38 13,000 350 94


Table 5Summary of Ozone MeasurementsLehigh Portland Cement Company

Union Bridge, MarylandHETA 96–0226

Location & Operation Date SamplingInstrument

ID Fan ElectrostaticPrecipitator

OzoneConcentration

(ppm)

Plant Yard – Background Dec. 3–4 color indicator tubeNA NA

ND

Metrosonic meter 0.02 – 0.03

Inside Front End of Kiln –Workers Replacing Kiln

Bricks

Dec. 3–4 color indicator tubeON OFF

ND

Metrosonic meter 0.03

Inside Back End of Kiln –Workers Replacing Kiln

Bricks

Dec. 3–4 color indicator tubeON OFF

ND


Just Outside Front End ofKiln – No Workers Inside

Kiln

Dec. 5 color indicator tubeOFF ON

0.6 – 0.7

Metrosonic meter 0.09 – 0.11

Through Portal in Back Endof Kiln – No Workers

Inside Kiln

Dec. 5 color indicator tubeOFF ON

>0.7


HETA 96–0226–2640 Lehigh Portland Cement Company Union … · 2002-06-14 · Daniel Almaguer...

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Transcript of HETA 96–0226–2640 Lehigh Portland Cement Company Union … · 2002-06-14 · Daniel Almaguer...