Laboratory storage of chemicals is an important aspect of chemical safety. While storage requirements and locations will vary significantly from laboratory to laboratory, the following general guidelines should be followed. Additional storage requirements for specific hazard classes are included in those sections.
A. Compatible Chemical Storage
Chemicals should always be segregated into compatible groups during storage to prevent hazardous reactions in the event of an accident. Storage areas and shelves should be clearly labeled as to their appropriate hazard class. The major laboratory chemical distributors have established color coded systems for chemical storage based on compatibility. Be aware that the systems vary somewhat between distributors. Appendix V(c)-A provides examples of incompatible chemical classes. Appendix V(c)-B provides examples for specific chemicals.
Manufacturers' container labels are the primary source of information on the physical and health hazards of a particular chemical. These labels should never be removed or defaced until the container is empty, and decontaminated if necessary (see Section XI for requirements for acutely hazardous waste). Empty bar-coded containers must be returned to the science center stockroom. Storage areas should be checked frequently to ensure that labels are tightly affixed to the container. Any loose labels should immediately be taped on using clear packing tape.
Bar-code labels are affixed to containers at the time of initial purchase or initial laboratory inventory. These bar-codes need to remain on the containers and should be reaffixed should they become loose. If a container is bar-coded, do not reuse the container. Return the empty container to the science center stockroom.
Containers into which chemicals are transferred or in which solutions are prepared must be labeled with, at a minimum, the chemical name. Containers larger than 1 liter in which the chemical is to be stored must also be labeled with appropriate hazard warning. All labeling should be done with a marker resistant to the contents of the container, or the label covered with clear tape.
C. Storage Areas
Storage areas should be isolated from working areas whenever possible. Exposure to heat or sunlight should be avoided; and storage areas for volatile chemicals should be ventilated when feasible. Bench tops should not be used for storage, and hazardous chemicals should not be stored on shelves between bench tops. Shelving should be sturdy and firmly anchored.
Storage in hoods severely diminishes their effectiveness, and is prohibited in hoods that are used for chemical handling. Hoods used to store noxious or acutely hazardous materials should be designated solely for storage.
All chemicals stored in hoods, on counters with a sink, or in any other area where a spill could reach a drain should be stored in secondary containment. The secondary containment must provide for separation of chemicals that are incompatible. Chemicals should not be stored on the floor with the exception of 5-gallon pails in secondary containment, or in areas well protected from foot traffic. Trays for use as secondary containment are available at no cost through the science center stockroom.
D. Chemical Evaluation
Faculty and departments should periodically review the chemicals stored in their laboratories and chemical storage areas. The review should answer the following questions with the resulting action as described. The Chemical Hygiene Officer or Stockroom Manager may request a review for the purposes of chemical inventory or regulatory compliance, and is available to assist with the review.
- Is the chemical still in use?
If the answer is yes, confirm that the container is labeled properly (chemical name and if >1L hazard(s)), the container remains in good condition (no rust, discoloration, disfigurement, contamination on the exterior, etc.) and that it is stored in the correct location. If necessary, relabel the container or repackage the chemical. If you are repackaging a bar-coded container, return the empty bar-coded container to the science center stockroom. If the answer is no, continue to question 2.
- Is the chemical still useable?
If the answer is no, due to age, contamination, deterioration, etc., then the chemical should be classified as waste and a hazardous waste determination done. If the answer is yes, continue to question 3.
- Will I use the chemical in this laboratory in the future?
If the answer is no, in that you no longer have a use for the chemical in your laboratory, and the chemical is in an original manufacturers container, then the material should be transferred to the centralized stockroom or department storage for use by others in your department or the sciences. If the chemical is not in the original manufacturer labeled container then it should be classified as waste.