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Chapter 7: Risk Management Lecture 2H. Section 7.3.1 Safety for Common Lab Operations

1. Incident 7.3.1.1 Explosion of a Non-Explosion-Proof Refrigerator

2. Learning Lab Operations and Safety Precautions from Othersa. Advanced and Research labs require learning new techniquesb. Written instructions can’t cover everything and can’t answer questionsc. Always ask an experienced colleague or supervisor for help and advised. You may have to go outside your lab to find help for new or rare techniquese. New Chemical Reactions

i. Reduce the scale of the literature reaction by a factor of 10ii. “Pilot Reactions” reduce the risks and give you experience and insightiii. Biggest challenge might be finding microscale or miniscale equipment

3. Safety Considerations for Common Lab Techniques and Equipmenta. A number of processes are common to many chemistry labsb. Accumulated wisdom (tricks of the trade) can make them safer

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4. Working Alonea. Working alone is not advised; instead use the “buddy system”b. Particularly if you are working with hazardous chemicals, someone in the lab

should know what you are using and what the hazards arec. Help during an incident (fire, explosion, exposure to a chemical) can be vital to

preventing a larger incidentd. If you must work alone, consider postponing riskier experiments

5. Sharps: glassware, needles, scalpels, etc….a. Cuts and punctures are probably the most frequent lab incidentb. Slow down. Use safety equipment if available. Consider alternatives

i. Inserting a glass tube through a stopper is a common hazardii. Use an insertion tool, wear gloves, and lubricate the tubing to lessen risk

c. Dispose of sharps appropriately—broken glass in trash will cut custodiansd. Sharps used in biology may be contaminated, in addition to being sharp

6. Weighinga. Balances and the area around balances are often contaminated during transferb. Toxic chemicals should be weighed/measured out in a hood—move the balancec. Clean up after yourself and dispose of any spilled chemicals appropriatelyd. Wear the appropriate glovese. Antistatic guns may be needed to reduce static charges which scatter powders

Especially problematic in the dry conditions of a glove box

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7. Mercury Thermometersa. Avoid their use if you can, but sometimes that is all you have b. Spilled mercury needs cleaned up quickly and properly by a trained personc. Mercury spill kits and mercury staining dyes can help ensure proper cleanup

8. Heatinga. Use spark-proof hot plates when heating flammablesb. Many older hot plates are not spark-proofc. Organic vapors are often heavier-than-air and will “pool” and then ignited. Working in a hood should help disperse flammable vaporse. Heating mantles are safe ways to heat

i. Resister (wire) covered by nonflammable materialii. Variable transformer controls current and thus temperature

f. Oil Baths are not-so-safei. Need an oil that won’t smoke or catch fire at your temp neededii. Silicone oil is often good up to 300 oC (check the label)iii. Mineral oil is a bad idea above 200 oC—will catch fire

g. Heat Gun = turbo-charged hair drieri. Use glowing hot coil to heat air: big-time ignition sourceii. Never use near flammablesiii. Run on “cool” (no heat, air cools coil) setting before turning off

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h. Ovensi. Often used to dry glassware and/or drying agentsii. Make sure all flammable solvents (acetone) have evaporated first (flush w/air)iii. Most don’t have any exhaust so fire hazard as well as chemical hazardiv. Don‘t use a mercury thermometer: heated mercury creates vapor if spilled

i. Microwave Ovensi. Some labs use off-the-shelf microwaves for some heating

- Not spark-proof: can’t use flammables- Flammables may catch on fire from heat without a spark anyway

ii. Don’t heat sealed containers: they can explode when heatediii. Superheated solvents (water) can “explode” when disturbediv. Microwave Synthesizers are becoming popular

- Designed to work with chemicals and to heat organic solvents- Follow all safety recommendations and study specific solvent behavior

j. Sonicatorsi. 16-100Hz (high frequency) sound generated into a bathii. Used to clean small parts or to help solids dissolveiii. Irritating sound can cause health problems: may want to insulate for soundiv. Tissue in contact with the sonicating bath solution can be damaged

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k. Chromatography = separation based on polaritya. Often use silica or alumina small particles as the stationary phaseb. Small particles can cause lung damage upon repeated exposurec. Solvents used are often toxic and/or flammabled. Do the chromatography in the hoode. “Flash Chromatography” pushes solvent with compressed air

- Have the right glassware and connections and use appropriate pressure- Glassware under pressure can break

l. Distillation and Refluxinga. Reflux = heating a reaction at the boiling point of the solventb. Distillation = purification of a liquid by boiling it away from contaminantsc. Water cooled condenser often used to return vapor to liquid stated. Secure water hoses with wire or clips to avoid flooding (especially overnight)e. If water cooling is lost, reaction my dry out, overheat, boil off solventf. Devices exist to turn off heating if water pressure is lostg. Distillation pot should always be placed on a lab jack

- Overheating: lower lab jack to lower heat source- Without a lab jack, you have to grab hot, spewing glassware to remove

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m. Recrystallization = precipitation of pure solid from a (hot) solutioni. Often involves flammable solventsii. Remove all ignition sourcesiii. Do in the hood to remove solvent vapors (toxic, flammable)iv. Don’t add a solid to a boiling solvent: causes it to boil overv. Add solid to cool solvent, then heat to boiling, then add more solvent

n. Extraction = transferring solute from one solvent to a more soluble solventi. Separatory funnel used to get the layers apartii. Shaking the funnel mixes the two solvent and allows movement of soluteiii. Vapors generated and pressure builds up: vent to release pressure

- Usually, the first extraction is the worst at building pressure: vent soon- Turn Separatory Funnel upside down and vent with valve at bottom

iv. Grease will seal stopper, but organic solvent dissolve greasev. Leaks are common—be vigilant, wear gloves, do in the hood

o. Stirringi. Stirring reactions ensures effective mixing, distributes heat, prevents bumpingii. Bumping = solution boils violently all at once, often splashes out iii. Teflon stir bars on a stirring hot plateiv. Motor driven stirrers with shaft into solution from top—viscousv. Spark-proof motors, stir reactions in hood to avoid vapors/aerosols

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p. Centrifuging: separating based on densityi. Bench-top models (500 rpm) to large floor models are used (30,000 rpm)ii. Get help from an experienced user of each specific centrifugeiii. Minimize breakage by balancing tubes on opposite sides (use plastic tubes)iv. If tubes break (tell by the noise), leave lid closed 1 hr for aerosols to settlev. Toxic or infectious? Use capped chambers for the tubes in case of breakage

q. Vacuum Pumpsi. Make sure guards cover any belts or other moving partsii. Exhaust into a hood if possible; oil collecting outflow traps are availableiii. Use cryogenic trap to prevent vapors from making it into the pump (and out)

r. Refrigerators and Freezersi. Only store chemicals in explosion proof refrigerators

- Internal light and thermostat switches eliminated or moved outside- Ordinary fridges will spark inside (and explode flammable vapors)

ii. Never store food or drinks in the lab fridge

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I. Radiation Safety1. Incident 7.3.2.1 Exposure to Airborne Plutonium

2. The Radiation Safety Programa. The Nuclear Regulatory Commission requires a license to use Ionizing Radiationb. Radiation Safety Program (RSP) managed by Radiation Safety Officer (RSO)c. If you don’t comply: may be contaminated and may lose privileges to use

3. Detecting Radiationa. Radiation can’t be detected by our senses, but can harm tissuesb. Passive Detector: badges that react with radiation over time to estimate exposurec. Active Detector: direct detection by reaction to ionizing radiation particles/ray

ALHLT 1021 RADIATION SAFETY AND PROTECTIONA comprehensive course designed to provide the student with principles of radiation protection. Radiation-protection responsibility by the radiographer to patients, personnel, and the public is presented, as well as self-protection methods for personnel working around ionizing radiation. Dose limit and regulatory involvement arediscussed, as well as radiation monitoring and measurement. F

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i. Geiger Counter: ionizing chamber gas reacts with radiation (click or count)- Portable, can be used to pinpoint radiation source- May not detect particles (a, b) that have to pass through surface

ii. Scintillation Detector: detecting material emits light when irradiated- Usually not portable, but more sensitive- Require collection of a sample to analyze

4. ALARA = As Low as Reasonably Achievablea. Since radiation causes biological damage, goal is to minimize exposureb. NRC has strictly enforced maximum dose limits (5 rem/year)

5. Instrument Radiation Sourcesa. X-Ray diffraction instruments (and others) generate ionizing radiation to functionb. Special training and education required to operatec. Methods to minimize exposure

i. Limit the time you are exposedii. Increase distance between you and the source (dose inverse square of distance)iii. Use shielding between you and the source:

- Lead is particularly effective- Charged particles (a, b) are more easily shielded because they interact

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6. Open Source Radiation: solids or solutions containing radiationa. Monitor work area frequently for contaminationb. Decontaminate and re-monitor if contamination is foundc. Work in a specialized chemical hood if any chance of aerosolsd. Use portable shielding when you openly handle radioisotopes

i. a-particles don’t penetrate skin, shielding usually not usedii. b-emitters: see-through acrylic shielding is effective (found in many labs)iii. Lead aprons and/or lead bricks used with g-rays or X-rays

e. Good safety practices and housekeeping: goggles, gloves, no eating, etc…f. Lock radioisotopes in secured container inside secured cabinet inside locked lab

J. Laser Safety1. Incidents 7.3.3.1 Eye damage from a pulsed laser

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2. Incident 7.3.3.2 Shock from a laser power supply

3. Laboratory Lasersa. LASER = Light Amplification by the Stimulated Emission of Radiation

i. Single wavelength of light (red pointer = 650 nm; green laser = 532 nm)ii. Very bright source of light

b. Principle Hazard is Eye Damagec. High Voltage power supplies are often used with lab lasersd. MPE = Maximum Permissible Exposure (watts/cm2, or joules/cm2)

Energy, wavelength, length of exposure, spatial coherence of laser determine MPE4. Old Laser Classes are still used (phased out starting 2002)

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5. New Laser Classes phased in since 2007

6. Eye Protection from Lasersa. Never stare directly into the beam of any laserb. Work with Class 3B or Class 4 lasers requires eye protectionc. No universal laser goggle (except a blindfold)d. Specific wavelength must be in mind when choosing eye protectione. Damage to retina most likely for 400-1400 nm, cornea damage 1400nm—1mmf. Lenses in protective goggles may be colored and reduce ability to see: keep in mindg. Laser goggles are not chemical splash goggles; may need different sets

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7. Safety Measures for Handling Lasersa. Educate yourself and get advice from experience users if you will use laserb. Key switches and safety locks required for Class 3B and Class 4 Lasersc. Never shine a laser at a reflective surface (mirror)d. Get training in using the high voltage power supply often needede. Only use laser pointers in Class 2 or 3R with power < 5 mW

K. Biological Safety Cabinets1. Incident 7.3.4.1 Meningitis in the Lab

2. Containment of Infectious Agents = Biosafetya. Exposure to a few molecules of a toxic chemical will probably not harm you.b. Exposure to just a few microbes may infect you.c. Emphasis: prevent exposured. Aerosols produced in the biological lab can carry microbes and be inhaled/ingested

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e. Fomite = inanimate object/surface acting as a point of exposurei. Ex: Glove to sink handle to bare hand to noseii. Hand-washing is particularly important in Biosafetyiii. Routine surface decontamination: remove organisms that can survive in airiv. Dilute Bleach = 1:100 household bleach to water or Alcohol (EtOH, i-PrOH)

3. HEPA (High Efficiency Particulate Air) Filtersf. Developed by the military to remove 99.97% of 0.3 mm particles from airg. Made from borosilicate glass fibers woven into a sheet; binder makes waterproofh. Folded into pleats to increase surface areai. Handle carefully: dropping may make ineffectivej. Must be tested once they are in placek. Minimize dust/aerosols in the lab so not to damagel. Special procedures for “bagging” exposed filter

4. BSC Classes

P = PersonalE = EnvironmentPr = ProductNV= non-volatileV = volatile

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5. Designa. Air drawn into the front of the hood goes downward through a HEPA filterb. Some is recirculated down the front of the hood: “curtain of air” protects “product”c. Some is exhausted through another HEPA filter back into the labd. Goals

a. Prevent “product” from being contaminatedb. Protection of the “personnel” from productc. Protection of the environment from product

e. Face velocity ~75-100 ft/min in fixed openingf. NOT Designed for chemicalsg. Safe for chemicals only if vented outsideh. Only use small amounts of volatile chemicals; otherwise, use chemical fume hoodi. Canopy can vent chemical vapors and provide normal lab airflow

6. Using BSC’sa. Get training by an experienced user in that labb. Most have a gauge measuring pressure drop across HEPA

i. Large pressure gain might mean clogged HEPA filterii. Large pressure drop might mean hole in HEPA filteriii. Either one means the filter is not protecting you any more

c. “Laminar Flow” = smooth air flow is required; impediments to flow are unsafe

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d. Don’t go in and out often (disrupts flow); have what you need before startinge. Small arm movements, straight in and out are better than large or side-to-sidef. BSL (Biosafety Level) determines what BSC you can useg. Work as far inside the BSC as you canh. Regularly decontaminate surfaces (bleach, alcohol); especially when turning oni. Let BSC run for a few minutes prior to use (get air flow stabilized)j. Use absorbent paper to contain any small spills or splashes; keep away from grillk. Biohazard bag for discarded items should be inside the hoodl. Autoclave glassware and contaminated material to decontaminate them

7. Certification and Testinga. BSC must be certified upon installation and tested yearlyb. Should be a sticker with the last test date on itc. Maintenance requires sterilization first, to protect maintenance workers

a. Formaldehyde, HOOH, or ClO2 vapors are usedb. Selection of the decontamination agent depends on the organisms used

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L. Protective Clothing and Respirators1. Incident 7.3.5.1 t-Butyllithium Fire and Fatality

2. Incident 7.3.5.2 Misuse of a Respirator

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3. Protective Clothing for the Laba. Lab Coats or Lab Aprons

i. Protects you from contaminants, splashes, exposuresii. Always wear if handling hazardous materialiii. Easy to remove quickly if splashed on, with 2nd layer of clothes protecting youiv. Never wear in public places—risk exposing others to hazardsv. Wash at work (if possible) or separately at homevi. Fire-resistant lab coats available if working with flammables

i. Nomex, Indura, or Excel have fire retardant in themii. Consider fire resistance of your own clothes as well: cotton > synthetics

vii. Chemical resistant materials can be used for lab coatsi. Tyvek, Proshield, NexGen, etc…ii. Won’t keep all chemicals out (just like gloves)

4. Respirators—The Last Resorta. Used where contaminated atmospheres are present to avoid breathing contaminantsb. Chemical Fume Hoods should provide the necessary protectionc. Labs should not require their use, unless something has gone wrong: spill cleanupd. Before you wear a respirator

i. Using the correct one and trained in its useii. Medically Fit for respirator use and Respirator is Properly Fitted to you

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5. Categories of Respiratorsa. Simple Masks

i. Often Disposable (use once or for period of time and dispose of)ii. N = not resistant to oil; P = resistant to oiliii. Number indicating percent efficiency: Ex: N95 or P100iv. Used by healthcare personnel in emergency environmentsv. Particulate filters only, don’t protect against gasesvi. Not suitable for the chemical labvii. Don’t provide a tight fit around mouth and nose

b. Cartridge Respiratorsi. Must provide a tight seal around the mouth and noseii. Forces all inhaled air through a cartridge filteriii. “Half-face” cover mouth and nose; “Full-face” cover entire faceiv. OSHA has a color code for the cartridges and what they can be used forv. OSHA requires a “Respiratory Protection Plan” for industry including “fit

testing” to ensure a proper seal around the facevi. Only trained, authorized personnel should use respiratorsvii. Generally applicable for industry; Lab conditions should not require them

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c. Self Contained Breathing Apparatus (SCBA)i. Used by firefighters or HAZWOPER trained respondersii. Clean air supply carried in a tank on the responder’s backiii. Specialized training is requirediv. Few Scientists would ever use SCBA during their careers

6. Before Using a Respiratora. Fitness, training, fit-testing: ignoring these can cause worse problem b. Not normal safety devices; generally used by experts as a last resort

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M. Safety in the Research Lab1. Incident 7.3.6.1 Runaway Research Reaction

2. Undergraduate Researcha. Research is doing something that has not been done beforeb. Exciting, rewarding, frustrating, even dangerousc. Many new hazards might be encountered d. Supervision may not be as direct as in Laboratory Coursese. Direct experience with “doing science” rather than learning about science

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3. Considerations When Performing Researcha. Consult an experienced researcher when faced with a new reaction or techniqueb. Formal and Informal safety information is transmitted this wayc. Attitude: When in doubt, ask. d. Safety culture in the research lab may not be ideal

i. Routine hazardous experiments dull respect for safetyii. By-passing safety measures in favor of “getting something done”iii. If the lab doesn’t value your safety, you don’t want to work in that lab.iv. You have to take responsibility for your own safety: insist on minimizing risk

e. Synthesizing new compounds: NO ONE KNOWS HOW TOXIC IT ISf. Think about worst-case scenario, and then act to avoid itg. Even when “experienced”, go over your procedure for new procedures with others

4. Safety Steps in Researcha. Consider safety questions BEFORE you do the experimentb. Know where the safety equipment, exits, etc… arec. Understand how waste generated will be disposed of (not down the sink)d. Unattended reactions

i. Post a sign nearby detailing reaction, start/stop times, contact number, etc…ii. Make sure sufficient gas, cooling water wired up, secondary containment, etc..

e. Supervisor might allow working alone in lab, if what you are doing is “safe”

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N. Process Safety for Chemical Operations1. Incident 7.3.7.1 Explosion from Scale-up of Reaction

2. What is Process Safety?a. Process Safety = developing and understanding hazards of a chemical process and

developing methods to safely manage and minimize the risksb. Chemical Industry uses this for new processes for industrial productionc. It really begins in the labd. Bhopal Tragedy an example of process safety gone wrong

3. Basic Concepts: Process Hazard Analysis (PHA)a. Team of chemists, engineers, managers go over every step identifying hazardsb. What can go wrong? is the approach they takec. Can’t manage the risk to a hazard you didn’t anticipated. Runaway reactions are particularly looked for and attempts made to eliminate them

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4. The Chemist’s Role in Process Safetya. Minimize hazardous chemicalsb. Substitute or replace hazardous materialsc. Moderate the conditions: lower temperature and pressured. Simplify the process: fewer steps

5. Ideal Industrial Process Chemical Stepsa. High yield with little or no by-productsb. Fast reaction kineticsc. Single phase (solution, gas, etc…)d. Ambient temperature and pressuree. Not strongly exothermicf. Insensitive to small changes in conditions

6. Process Safety Management (PSM)a. OSHA established performance standards for industry following incidents in 80-

90’sb. Performance standard to make sure PHA is followedc. Example: Failure to use PSM

i. Synthron Explosion in Morgantown, North Carolina in 2006ii. Shows how PSM could have been more effectively used

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