Chemical Storage and Segregation
Proper chemical storage is a necessity for any laboratory using hazardous materials. By adhering to a few simple guidelines laboratories can minimize the hazards associated with leaks, spills, and accidental comingling of incompatible chemicals.
- Compressed gases. Use appropriate handcarts to move compressed gas cylinders. Gas cylinders should be capped and secured to a cart during transport. Highly toxic gases should not be moved through the corridors, particularly during business hours. Always consider cylinders as full and handle them with corresponding care.
- Gas cylinders should be stored in well-ventilated areas with their protective caps on. Gas cylinders should be secured (i.e., strapped or chained in place) to reduce the chance of being knocked over. Do not store cylinders near heat or high traffic areas. Do not store flammables and oxidizers together or empty and full cylinders together. Storage of large quantities of cylinders should be in an approved gas cylinder storage area.
- Containers. Verify the integrity of all containers. If deteriorated containers are found, dispose of the chemical, or transfer it to a properly labeled new container. Make sure that the container is appropriate for the chemical stored. For example, hydrofluoric acid must not be stored in glass, and some oxidizers should not be stored in plastic containers. Halogenated solvents may not be stored in metal safety cans due to the potential for corrosion.
- Cryogenic liquids. These items present the potential hazards of fire or explosion, pressure buildup, embrittlement of structural materials, frostbite, and asphyxiation. Work areas must be well ventilated. Cryogenic liquids must be stored, shipped, and handled in containers that are designed specifically for this purpose. Because of the extreme cold and splash hazards, skin protection and eye protection — preferably a face shield — should be worn when handling cryogenic liquids. First-time users of cryogenic liquids should have direct supervision and instruction from an experienced user when attempting transfers from one container to another.
- Handling. Use poly-coated bottles or bottle carriers when transporting chemicals that are in glass containers. Pour chemicals carefully and close caps securely. Never add water to concentrated acid; instead prepare dilute solutions by adding acid to water. Containers holding more than five gallons should be grounded when transferring flammable liquids. Provide secondary containment for liquids when moving them between work areas.
- Inventory. Inventories should be reviewed on a regular basis to identify deteriorating chemicals before they become problems, and to avoid excess purchases. Having updated inventories improves emergency responses, helps EHS with activities such as hazardous waste determinations and safety reviews, and allows participation in the campus wide recycling program.
- Registered Users are required to maintain an inventory of all hazardous materials in their work areas. EHS also requires Registered Users to submit an inventory of hazardous materials at least annually. To assist Registered Users with these inventories, EHS has established a Hazardous Material (Chemical) Inventory System. The on-line inventory system allows Registered Users to confirm that they have completed an annual inventory, print copies of the inventories, and query the entire database to determine if a certain hazardous material is available on campus.
- Labels. Make sure all labels are legible. Label all containers of hazardous materials with the chemical name and appropriate hazard class. Containers of non-hazardous materials need only to be labeled with the chemical name. Instructions on labeling unwanted hazardous materials can be found on the Chemical Labeling page.
- Date all peroxidizable and other chemicals which may become unstable over time; test and/or dispose of them when appropriate. Common examples of chemicals that form peroxides upon aging are ethyl ether, isopropyl ether, tetrahydrofuran, and dioxane. See the Peroxide Forming Chemicals page for a more complete listing of chemicals that can form peroxides upon aging.
- Storage. Avoid storing chemical containers in hard to reach areas. Containers larger than one gallon should not be stored above shoulder height. Chemicals should be segregated by hazard classification to avoid incompatibilities. Once segregated by hazard class, chemicals may be stored alphabetically. EHS recommends the following as a minimum:
- store flammable solvents in a flammable storage cabinet; non-flammable solvents may be stored in the same cabinet
- store concentrated acids in a separate storage cabinet
- keep strong oxidizers away from organic materials
- keep acids away from bases
- keep cyanides and sulfides away from acids
- Laboratories with large numbers of hazard classifications may choose to further segregate chemicals.
- Volatile chemicals may be stored temporarily in fume hoods when flammable storage cabinets are unavailable. If volatile substances are stored in a hood, other uses of the hood should be restricted to activities compatible with the chemical and physical properties of the stored or used chemicals. When volatiles must be stored in a cooled atmosphere, flammable material refrigerators, explosion-proof refrigerators, or cold rooms designed specifically for this purpose must be used.
The manual Prudent Practices in the Laboratory: Handling and Management of Chemical Hazards provides an authoritative reference for the handling and disposal of chemical at the laboratory level. While this book provides an excellent resource for faculty, students, and staff, it may contain information that is contradicted by current MU EHS protocols and therefore it should be used only as a general reference source.