Summary 7 Read: Prudent Practices Ch 4 p. 67­77; Ch 5 p. 81­105 Safety in Academic Labs – Vol. 1, p. 6­9 Acquisition of Chemicals (Purchasing Chemicals) 1. Before purchasing, verify that the chemical is not already in stock 2. Purchase the minimum quantity required for the current use – the cost of disposing of the excess material is likely to exceed the savings from the bulk purchase 3. Verify that you will not be exceeding the maximum quantity of a material allowed in the storage area. Fire codes regulate the quantities of certain materials like flammables and combustibles. 4. Make sure that the material can be managed safely when it arrives – whether it needs refrigeration, a freezer, or a dry box. 5. Extremely unstable materials must be used right away and may require overnight delivery. 6. Verify that the waste can be managed in a satisfactory manner. Decentralizing purchasing makes it more difficult to verify that all these issues have been addressed. A central network of MSDSs should be available. Receiving Chemicals Delivery of chemicals should be to areas that are equipped to handle them such as a loading dock, receiving room, or laboratory. Chains for temporary holding of cylinders and carts designed to safely move various types of chemical containers should be available. Shelves, tables, or caged areas should be used for packages to avoid damage. Receiving room and loading dock personnel should be trained to recognize hazards associated with the chemical they handle and should know how to respond if a package is leaking or if there is a spill. The Department of Transportation (DOT) requires training for anyone involved in the movement (including receiving) of hazardous materials. Chemicals should be transported safely within the facility, preferably in freight only elevators. Cylinders of compressed gases should be secured on carts. The cap should be in place. Due to insurance regulations, the use of privately owned personal vehicles for transport is forbidden. Anyone who needs to transport regulated materials personally between buildings within an institution should walk. Secondary containment, such as a rubber bucket, should always be used for carrying bottled chemicals. When packages are opened in the laboratory, it should be verified that the container is not damaged and there is the required label. The date of receipt should be written on the label and the chemical should be stored in the appropriate location. The chemical should be entered into the labs chemical inventory. Inventory and Tracking of Chemicals A well­managed inventory system can promote economical use of chemicals by making it possible to determine immediately what chemicals are on hand. Information on chemicals with storage or disposal problems helps with planning for their handling.
The following data fields for each item in a chemical inventory:
name as printed on the container,
molecular formula, for further identification and to provide a simple means of searching,
· Chemical Abstract Service (CAS) registry number, for unambiguous identification of chemicals despite the use of different naming conventions,
· source, and
· size of container. · · In addition, the following information may be useful:
hazard classification, as a guide to safe storage, handling, and disposal,
date of acquisition, to ensure that unstable chemicals are not stored beyond their useful life, and
· storage location, in laboratories where multiple locations exist. · · Consider the following general rules for disposing of chemicals
· · · · · · · Dispose of chemicals that will not to be needed within a reasonable period, say, 2 years.
Make sure that deteriorating containers, or containers in which evidence of a chemical change in the contents is apparent (e.g., appearance of peroxide crystals in a bottle of an ether), are inspected and handled by someone experienced in the possible hazards inherent in such situations.
Dispose of or recycle chemicals before the expiration date on the container.
Replace deteriorating labels before information is obscured or lost.
Dispose of odiferous items from storage and inventory as soon as possible.
Dispose of chemicals that require storage at reduced temperature in environmental rooms or refrigerators as soon as possible ­ these chemicals may include air­ and moisture­sensitive materials, they are especially prone to
Dispose of, or remove to storage, all hazardous chemicals at the completion of the laboratory supervisor's tenure or transfer to another laboratory. The institution's cleanup policy for departing laboratory researchers and students should be enforced strictly to avoid accumulation of expensive orphaned unknowns. Labeling Commercially Packaged Chemicals When chemicals from commercial sources repackaged into secondary containers, the new containers should be labeled with all essential information on the original container. The label should contain:
· · · name, address, and telephone number of the chemical manufacturer
chemical identification and identity of hazard component(s)
appropriate hazard warnings.
Labeling Other Chemical Containers and Experimental Materials The contents of beakers, flasks, reaction vessels and process equipment, should be properly identified. The name of the researcher responsible, and other information, such as a laboratory notebook reference, that can readily lead to what is known about the material is important. The Chemical Inventory and Emergency Planning The most important assistance to have in an emergency is access to knowledge about the chemical(s) involved. An organization's emergency preparedness plan should include components on what to do in the event of a hazardous materials release. Storage of Chemicals in Stockrooms and Laboratories Radioactive materials, controlled substances (drugs), consumable alcohol, explosives, needles, hazardous waste, etc. have requirements ranging from locked storage cabinets and controlled access to specified waste containers and "regulated" areas. General Storage Considerations
· · · · · · · · · · · · · Avoid storing materials and equipment on top of cabinets. Maintain a clearance of at least 18 inches from the sprinkler heads to allow proper functioning of the sprinkler system.
Do not store materials on top of high cabinets where they will be hard to see or reach.
Avoid storing heavy materials up high.
Keep exits, passageways, areas under tables or benches, and emergency equipment areas free of stored equipment and materials.
Label all chemical containers appropriately with the user’s name and date
Provide a definite storage place for each chemical and return the chemical to that location after each use.
Avoid storing chemicals on bench tops
Avoid storing chemicals in laboratory hoods
Store volatile toxics and odoriferous chemicals in a ventilated cabinet. Check with the institution's environmental health and safety officer.
Provide ventilated storage near laboratory hoods.
If a chemical does not require a ventilated cabinet, store it inside a closable cabinet or on a shelf that has a lip to prevent containers from sliding off in the event of a fire, serious accident, or earthquake.
Do not expose stored chemicals to heat or direct sunlight.
Observe all precautions regarding the storage of incompatible chemicals. TABLE 4.1 Related and Compatible Storage Groups Inorganic Family Nitric acid, other inorganic acids Metals, hydrides Halides, sulfates, sulfites, thiosulfates, pentoxide Sulfur, phosphorus, arsenic, phosphorus Organic Family
phosphates, halogens Amides, nitrates (except ammonium nitrate) , nitrites, azides Hydroxides, oxides, silicates, carbonates, carbon Sulfides, selenides, phosphides, carbides, nitrides Chlorates, perchlorates, perchloric acid, chlorites, hypochlorites, peroxides, hydrogen peroxide Acids, anhydrides, peracids Alcohols, glycols, amines, amides, imines, imides Hydrocarbons, esters, aldehydes Ethers, ketones,ketenes, halogenatedhydrocarbons, ethylene oxide Epoxy compounds, isocyanates Peroxides, hydroperoxides, azides Arsenates, cyanides, cyanates Sulfides, polysulfides, sulfoxides, nitrites Borates, chromates, manganates, permanganates Phenols, cresols NOTE: Store flammables in a storage cabinet for flammable liquids or in safety cans. Separate chemicals into their organic and inorganic families and then related and compatible groups, as shown. Separation of chemical groups can be by different shelves within the same cabinet. Do NOT store chemicals alphabetically as a general group. This may result in incompatibles appearing together on a shelf. Rather, store alphabetically within compatible groups. This listing is only a suggested method of arranging chemical materials for storage and is not intended to be complete. TABLE 4.2 Storage Limits for Flammable and Combustible Liquids for Laboratories: B Classification with Sprinkler System Class of Liquid Flash Point ( o C) Amount (gallons per 100 square feet) Class I Flammable Below 38 4 Class II Combustible 38­60 4 Class IIIA Combustible 60­93 12 Class IIIB Combustible Above 93 Unlimited NOTE: Liquid (pumpable) flammable waste is included in the storage limitation. Non­pumpable waste is not included. Locations with an H (hazard) classification have much higher limits. Inside storage rooms for flammable liquids, the limits are from 5 to 10 gallons per square foot, depending on the size and construction of the room. SOURCE: NFPA (1991c), Chapter 2­2, "Laboratory Unit Fire Hazard Classification." TABLE 4.3 Container Size for Storage of Flammable and Combustible Liquids Container Glass c Metal or approved plastic Safety cans Flammable Liquids a Combustible Liquids b Class IA Class IB Class IC Class II Class IIIA Liters Gallons Liters Gallons Liters Gallons Liters Gallons Liters Gallons 0.5 0.12 1 0.25 4 1 4 1 4 1 4 1 20 5 20 5 20 5 20 5 7.5 2 20 5 20 5 20 5 20 5 Containers and Equipment
·Use corrosion­resistant storage trays or secondary containers to retain materials if the primary container breaks or leaks.
·Provide vented cabinets beneath laboratory hoods for storing hazardous materials. Chemical Storage Refrigerators
· · Use chemical storage refrigerators only for storing chemicals.
Label these refrigerators with the following signage:NO FOOD—CHEMICAL STORAGE ONLY
Seal containers to minimize escape of corrosive, flammable, or toxic vapors.
Label all materials in the refrigerator with contents, owner, date of acquisition or preparation, and nature of any potential hazard.
· Only store flammable liquids in an explosion proof refrigerator. · · Storing Flammable and Combustible Liquids Store combustibles in their original containers or in safety cans. Whenever possible, store 1 liter or greater quantities of flammables in cans. The National Fire Protection Association (NFPA) limits the quantity of flammable and combustible liquids per 100 ft 2 of laboratory space as shown in Table 4.2 for Lab B Classification with Sprinkler Systems. Container sizes are shown in Table 4.3. Storing Highly Reactive Substances
Dispose of (or recycle) highly reactive material prior to expiration date.
Do not open, but call your institution's hazardous waste coordinator for special instructions if a container of highly reactive material is past its expiration date or a liquid organic peroxide or peroxide former contains crystals.
· Segregate the following materials: o oxidizing agents from reducing agents and combustibles, o powerful reducing agents from readily reducible substrates, o pyrophoric compounds from flammables, and o perchloric acid from reducing agents.
· · · · · · · Store highly reactive liquids in trays large enough to hold the contents of the bottles.
Store perchloric acid bottles in glass or ceramic trays.
Store peroxidizable materials away from heat and light.
Store materials that react vigorously with water away from possible contact with water.
Store thermally unstable materials in a refrigerator. Use a refrigerator with these safety features: o all spark­producing controls on the outside, o a magnetic locked door, and o an alarm to warn when the temperature is too high. Storing Toxic Substances
Store chemicals known to be highly toxic (including carcinogens) in ventilated storage in unbreakable, chemically resistant secondary containers.
· Keep quantities at a minimum working level.
· Label storage areas with appropriate warning signs, such as · CAUTION! REPRODUCTIVE TOXIN STORAGE or CAUTION! CANCER­SUSPECT AGENT STORAGE and limit access to those areas.
· Maintain an inventory of all highly toxic chemicals. Recycling Recycling some of the chemicals used in large undergraduate courses may be especially cost effective because the needs of the users are known well in advance. Recycling activities may require a waste treatment permit under the Resource Conservation and Recovery Act (RCRA). This issue is discussed in Chapter 9. Solvents may be recycled by distillation. Mercury may be cleaned of particulates by slowly poring through conical filter paper. Some heavy metals may be recovered by precipitation. Review of Working with Chemicals 1. Observe professional personal behavior 2. Minimize exposure to chemicals 3. Follow good house keeping practices 4. Transport chemicals properly –chemicals in break­resistant secondary containers and gas cylinders strapped to carts. 5. Store chemicals as described earlier. 6. Equipment and glassware should be well­maintained 7. For a fire to start, an ignition source, fuel, and oxidizer must be present. To prevent a fire make sure one or more components is not available. 8. When scaling up a reaction additional cooling may be necessary for exothermic reactions.
9. Avoid working alone in the lab. Design unattended experiments so that if there is an interruption of utility service no hazardous substances are released. If possible, arrange for periodic inspections. Disposal of Chemicals
· Hazardous or flammable waste solvents should be collected in an appropriate container before transfer to the satellite site and pickup by an outside disposal agency. Waste solvents can usually be mixed for disposal, with due regard for the compatibility of the components. However, halogenated and nonhalogenated wastes must be segregated for separate handling.
· · · · · · · The container used for the collection of liquid waste must be appropriate for its use. Glass bottles are impervious to most chemicals but present a breakage hazard, and narrow necks can cause difficulty in emptying the bottles. The use of plastic (e.g., polyethylene jerrycans) or metal (galvanized or stainless steel) safety containers for the collection of liquid waste is required for flammable liquids.
Galvanized steel safety cans should not be used for halogenated waste solvents because they tend to corrode and leak. Flame arresters in safety cans can easily become plugged if there is sediment and may need to be cleaned occasionally.
Waste containers should be clearly and securely labeled as to their contents and securely capped when not in immediate use.
Aqueous waste should be collected separately from organic solvent waste. Glass should not be used for aqueous waste if there is danger of freezing. Adjustment of the pH of aqueous waste may be required. Such adjustment requires consideration of the possible consequences of the neutralization reaction that might take place: gas evolution, heat generation, or precipitation.
Solid chemical waste, such as reaction by­products, or contaminated filter or chromatography media, should be placed in an appropriately labeled container to await disposal or pickup.
Unwanted reagents should be segregated for disposal in their original containers, if possible. If original containers are used, labels should be intact and fully legible. Every effort should be made to use, share, or recycle unwanted reagents
Nonhazardous solid waste can be disposed of in laboratory trash or segregated for recycling Responding to Accidents and Emergencies Everyone working in a lab should know the following:
How to report a fire, injury, chemical spill, or other emergency to summon emergency response;
· The location of emergency equipment such as safety showers and eyewashes;
· The location of fire extinguishers and spill control equipment; and
· · The locations of all available exits for evacuation from the laboratory. Handling the Accidental Release of Hazardous Substances 1. Notify other laboratory personnel of the accident and, if necessary, evacuate the area 2. Tend to any injured or contaminated personnel and, if necessary, request help. 3. Take steps to confine and limit the spill if this can be done without risk of injury or contamination 4. Clean up the spill using appropriate procedures. Dispose of contaminated materials properly. Treatment of Injured and Contaminated Personnel Spills on Skin 1. Immediately flush with flowing water for no less than 15 minutes. 2. If there is no visible burn, wash with warm water and soap, removing any jewelry to facilitate clearing of any residual materials. 3. Check the Material Safety Data Sheet (MSDS) to see if any delayed effects should be expected. 4. Seek medical attention for even minor chemical burns. 5. Do not use creams, lotions, or salves. Spills on Clothes 1. Do not attempt to wipe the clothes. 2. Quickly remove all contaminated clothing, shoes, and jewelry while using the safety shower. 3. Seconds count, so do not waste time because of modesty. 4. Take care not to spread the chemical on the skin or, especially, in the eyes. Use caution when removing pullover shirts or sweaters to prevent contamination of the eyes; it may be better to cut the garments off. 5. Immediately flood the affected body area with warm water for at least 15 minutes. Resume if pain returns. 6. Get medical attention as soon as possible. 7. Discard contaminated clothes or have them laundered separately from other clothing. Splashes in Eyes 1. Immediately flush with tepid potable water from a gently flowing source for at least 15 minutes. 2. Hold the individual's eyelids away from the eyeball, and instruct him or her to move the eye up and down and sideways to wash thoroughly behind the eyelids.
3. Use an eyewash. If one is not available, place the injured person on his or her back and pour water gently into the eyes for at least 15 minutes. 4. Follow first aid by prompt treatment by a member of a medical staff or an ophthalmologist who is acquainted with chemical injuries. Spill Containment Typical spill kits contain:
· · · · · · Spill control pillows. These commercially available pillows generally can be used for absorbing solvents, acids, and caustic alkalis, but not hydrofluoric acid.
Inert absorbents such as vermiculite, clay, sand, kitty litter, and Oil Dri ® . Paper is not an inert material and should not be used to clean up oxidizing agents such as nitric acid.
Neutralizing agents for acid spills such as sodium carbonate and sodium bicarbonate.
Neutralizing agents for alkali spills such as sodium bisulfate and citric acid.
Large plastic scoops and other equipment such as brooms, pails, bags, and dust pans.
Appropriate personal protective equipment, warnings, barricade tapes, and protection against slips or falls on wet floor during and after cleanup. Spill Clean­up – General Guidelines
Materials of low flammability that are not volatile or that have low toxicity. This category of hazardous substances includes inorganic acids (e.g., sulfuric and nitric acid) and caustic bases (e.g., sodium and potassium hydroxide). For cleanup, appropriate protective apparel, including gloves, goggles, and (if necessary) shoe coverings should be worn. Absorption of the spilled material with an inert absorbent and appropriate disposal are recommended. The spilled chemicals can be neutralized with materials such as sodium bisulfate (for alkalis) and sodium carbonate or bicarbonate (for acids), absorbed on Floor­Dri ® or vermiculite, scooped up, and disposed of according to the procedures detailed in Chapter 7, section 7.B.8.
· Flammable solvents. Fast action is crucial when a flammable solvent of relatively low toxicity is spilled. This category includes petroleum ether, pentane, diethyl ether, dimethoxyethane, and tetrahydrofuran. Other workers in the laboratory should be alerted, all flames extinguished, and any spark­producing equipment turned off. In some cases the power to the laboratory should be shut off with the circuit breaker, but the ventilation system should be kept running. The spilled solvent should be soaked up with spill absorbent or spill pillows as quickly as possible. These should be sealed in containers and disposed of properly. Nonsparking tools should be used in cleanup.
· Highly toxic substances. The cleanup of highly toxic substances should not be attempted alone. Other personnel should be notified of the spill, and the appropriate safety or industrial hygiene office should be contacted to obtain
· assistance in evaluating the hazards involved. These professionals will know how to clean up the material and may perform the operation. Handling Leaking Gas Cylinders – in all cases signs should be posted that describe the hazards and state warnings. Flammable, inert or oxidizing gases ­ move to an isolated area, away from combustible material if the gas is flammable or an oxidizing agentExercise care when moving leaking cylinders of flammable gases so that accidental ignition does not occur. If feasible, leaking cylinders should always be moved into laboratory hoods until exhausted. Corrosive and toxic gases ­ Corrosive gases may increase the size of the leak as they are released. The cylinder should be moved to an isolated, well­ventilated area, and suitable means used to direct the gas into an appropriate chemical neutralizer. Mercury spills ­ isolate the spill area and begin the cleanup procedure. Those doing the cleanup should wear protective gloves. The cleanup should begin with collecting the droplets. Commercial mercury spill cleanup sponges and spill control kits are available.