General Storage Rules
- Do not sort and store chemicals alphabetically unless they have first been separated into hazard classes.
- Ensure that caps and lids on all chemical containers are tightly closed to prevent evaporation of contents.
- Avoid storing chemicals on countertops or in fume hoods except for those being currently used. In these locations chemicals are more readily knocked over, laboratory personnel chance of exposure is greatly increased, and the chemicals are unprotected if a fire were to occur in the laboratory.
- Chemicals must never be stored on the floor, not even temporarily, to greatly reduce the chance that the chemical is knocked over by someone who does not see the container.
- Spill trays can be used in situations, such as tissue culture vacuum lines, to contain chemical or media waste bottles.
- Chemicals should be dated when received and when opened. If the chemical is one that degrades in quality or becomes unsafe after prolonged storage, the shelf-life expiration date should also be included.
- Maintain a permanent inventory that is verified annually.
- Do not store chemicals (except cleaners) under sinks.
- Avoid stockpiling chemicals. Purchase only what is needed.
- Conduct periodic cleanouts to prevent accumulating unnecessary chemicals.
- Chemicals that are no longer to be used for research purposes should be properly disposed of or given to another research group that has a use for it.
- Avoid exposure of chemicals to heat or direct sunlight. This may lead to the deterioration of storage containers and labels, as well as the degradation of the chemicals.
- Flammable materials (flammable liquids, flammable solids, etc) must be stored in a certified flammable safety cabinet.
- NEVER store flammable liquids in a domestic refrigerator. Only laboratory safe, explosion proof, or certified flammable liquid refrigerators can be used to store solvents.
Specific Storage Requirements
- Segregate oxidizing acids from organic acid and flammable and combustible materials.
- Segregate acids from bases.
- Segregate acids from reactive metals such as sodium, potassium, and magnesium.
- Store acetic acid as a flammable liquid. This is an organic (carboxylic) acid that will react if it comes in contact with an oxidizing acid.
- Nitric acid and hydrochloric acid may be stored in the same corrosive storage cabinet, but they must be kept in separate drip trays. These can combine to form chlorine and nitrosyl chloride gases—both are toxic.
- Segregate acids from chemicals that could generate toxic or flammable gases upon contact, such as sodium cyanide, iron sulfide and calcium carbide.
- Segregate bases from acids, metals, explosives, organic peroxides and easily ignitable materials.
- Do not store aqueous sodium and potassium hydroxide solutions in aluminum drip trays. These will corrode aluminum.
Solvents (flammable and combustible liquids)
- Store in approved safety cans or cabinets.
- Segregate from oxidizing acids and oxidizers.
- Keep away from any source of ignition: heat, sparks, or open flames.
- Never store flammable liquids in a domestic refrigerator. Only laboratory safe, explosion proof, or certified flammable liquid refrigerators can be used to store solvents.
- Keep away from combustible and flammable materials.
- Keep away from reducing agents such as zinc, alkali metals, hydrazine, oxalic acid, and formic acid.
- Segregate from aqueous solutions, acids and oxidizers.
- Store in a cool, dry place, away from any water source.
- Make certain that a Class D fire extinguisher is available in case of fire.
- If in original container store in a cool, dry place, making provisions for an airtight seal.
- Store in a glove box after the material has been opened.
- Store in amber bottles in a cool, dry, dark place.
- Most peroxide forming chemicals are also flammable liquids. Therefore, store in airtight containers in a flammable storage locker.
- Segregate from oxidizers and acids.
- Store according to the nature of the chemical, using appropriate security where necessary.
Flammable Liquid Storage
All flammable and combustible liquids and solids must be stored in an appropriate manner to ensure that people and property are protected from fire and explosion hazards presented by these classes of chemicals. In Case laboratories, if there is more than 2 gallons (7.6 liters) net volume in an area of flammable liquids or solids, all flammable material must be stored in a certified flammable storage cabinet when it is not in use.
Flammable storage cabinets are an important component of fire safety because they will extend the amount of time it takes for a fire to spread to other areas, thus allowing personnel time to escape and time for fire protection to arrive. The following information can be found in the Case EHS Standard Operating Procedure for Flammable Safety Cabinets (PDF attachment):
- Maximum allowed flammable liquids in a laboratory
- Location of and storage of Flammable Storage Cabinets
- Recommended size of Flammable Liquid Storage Cabinets for different amounts of material
Why should solvents never be stored in a domestic refrigerator?
- A flammable liquid is defined, by the OSHA Hazard Communication Standard any liquid, which has a flashpoint at or below 93°C (200°F). (Flashpoint is the lowest temperature at which a liquid can form an ignitable mixture in air near the surface of the liquid. The lower the flash point, the easier it is to ignite the material.)
- Refrigerator temperatures are typically higher than the flash points of flammable liquids stored inside, therefore vapor accumulation can occur.
- There are a number of sources of ignition which are within or exposed to the refrigerated storage area of a standard domestic fridge such as thermostats, light switches, and heater strips.
- Vapors from flammable liquid spills or leaks can readily accumulate in the bottom of a refrigeration unit which is where the compressor and it's circuits are typically located.
- All of these factors combined create a situation where the possibility of fire and explosion is high.
- The table below indicates a number of frequently refrigerated substances that should never be stored in a domestic refrigerator:
|Chemical||Flash point (°F)||Chemical||Flash point (°F)|
Storing chemicals by compatibility will prevent certain accidents from occurring in the laboratory. Chemicals can be stored by compatibility by following these four easy steps for each chemical that you wish to store together.
1. Identify the Chemical Hazard
Physical: Corrosive, Flammable, Oxidizer, Reactives
Segregate chemicals into like type hazards. Be aware that some chemicals have multiple hazards and therefore require further segregation.
2. Determine the pH Value
Acid, Neutral, Base
Continue to segregate the chemical groups by identifying if they are acidic (pH < 4), neutral (pH 4 - 10), or basic (pH > 10).
3. Inorganic or Organic
Identify whether a chemical is an inorganic or organic compound. Organic compounds have carbon (C) in the chemical formula. (The C must not be followed by another lowercase letter: Cd is cadmium, Ca calcium, Cl chlorine (Cl), etc.). This step is extremely important for the segregation and storage of corrosives and oxidizing chemicals.
4. Solid or Liquid
Solid and liquid chemicals should be stored separately to minimize the involvement of chemicals in the event of a liquid spill.
Once all information has been complied for the chemical you want to place into storage, compare the information. The chemicals that have the same answers in all 4 categories can be stored in the same secondary containment. If one category is different, other storage options must be examined such as segregation with spill trays or storage in different areas.
This quick guide to chemical compatibility (pdf) is available in a printable version which includes a table that can be used to compile the necessary information and safely store laboratory chemicals.
A more elaborate chemical compatibility chart (pdf) is also available.
If you have any questions you should contact EHS at (216) 368-2907.