7.9.1 General Storage Guidelines

Laboratories should adhere to the following storage guidelines for the proper and safe storage of chemicals. By implementing these guidelines, laboratories can ensure safer storage of chemicals and enhance the general housekeeping and organization of the lab. Proper storage of chemicals also helps utilize limited laboratory space in a more efficient manner.

Receipt and Unpacking

This is where chemical lifecycle management begins. Deferred unpacking is one of the most common sources of chemical inventory gaps and fire load accumulation.

• Remove chemicals from all shipping packaging immediately upon receipt. Cardboard boxes and Styrofoam inserts must not remain in chemical storage areas. These are combustible materials.
• Combustible packing materials must not be stored in any space designated for hazardous chemicals, including H-occupancy rooms (H-rooms), flammable storage rooms and cabinets, and areas where chemicals are actively used.
• Shipping containers and packaging are for transport only. Once a chemical is placed in its designated storage location, all packaging must be removed and disposed of.
• Date the container upon receipt.
• Immediately inventory the chemical after receiving and unpacking. 

Note on floor storage during receiving: Temporary floor placement during active unpacking is acceptable. Chemicals must be moved to designated storage before personnel leave the area.  No chemicals should be stored long-term on the floor.

Labeling

An unlabeled container is, by definition, an unknown hazard.

• All chemical containers must be labeled at all times with:
  • Full chemical name
  • Hazard information 
• Inspect labels regularly. Replace any label that is deteriorating, obscured, or detaching before the chemical becomes unidentifiable.
• Secondary containers (beakers, transfer vessels, aliquots) must be labeled even for short-term use. 
• Label the exterior of all refrigerators and freezers: indicate contents category (e.g., “Chemicals only, no food or beverages”).

Segregation and Compatibility

Storing chemicals by alphabet is a known cause of laboratory fires and toxic gas releases. Alphabetical order places Acetic acid next to Acetone (flammable + oxidizer-adjacent), or Nitric acid next to Nitromethane (oxidizing acid + flammable solvent).

Store all chemicals by hazard class compatibility, not by name. Consult the chemical’s SDS Section 7 (Handling/Storage) and Section 10 (Reactivity) to confirm compatibility before placing it in storage.

Please see Chapter 7.11: Chemical Segregation for more guidance on chemical segregation.

Special Hazard Class Requirements

Please see Chapter 8: Chemical Hazards for more guidance on chemical hazards.

Flammable and Combustible Liquids

• It is best practice to store flammable chemicals in properly rated flammable storage cabinets.  EHS can assist in the selection on the appropriate storage cabinet for your lab.
• Do not store acids in flammable storage cabinets. Acid vapors degrade cabinet integrity and accelerate corrosion of stored containers.
  • Exception: Certain organic acids are classified as both flammable and corrosive. Acetic acid is a common example and concentrations of acetic acid over 80% need to be stored in a flammable cabinet. 
• Do not store flammable liquids in standard (non-explosion-proof) refrigerators or freezers. Only store flammables in units explicitly rated by the manufacturer for flammable storage.
• Fume hood storage of chemicals must be limited to the experiment in progress. Excess containers reduce airflow, decrease working space, and increase fire and spill risk.

Corrosive Chemicals

• Corrosive liquids must be stored in corrosion-resistant cabinets.
• Corrosive chemicals must not be stored above eye level. In general, it is best practice that no chemicals be stored above eye level.
• Secondary containment is required for all liquid corrosive containers.

Peroxide Forming Chemicals

Please see Chapter 8.7 Peroxide Forming Compounds for more guidance on peroxide forming chemicals.

Peroxide forming chemicals are capable of forming shock-sensitive crystalline peroxides over time. Risk varies significantly by chemical class:

• High risk: require strict dating, periodic testing, and disposal on schedule: diethyl ether, THF, 1,4-dioxane, diisopropyl ether, 1,3-dioxolane, and other cyclic or branched ethers.
• Lower risk: relevant only under adverse conditions (prolonged storage, light exposure, elevated temperature): isopropanol, ethanol, certain alkenes. 
• Date all peroxide-forming containers at receipt.
• Test for peroxide formation every 6 months.
• Dispose of peroxide-forming chemicals that have exceeded their safe storage period. Do not attempt to open containers with visible crystals. Contact EHS immediately.
• Maintain only the quantity needed. Do not allow peroxide-formers to accumulate.

Particularly Hazardous Substances (PHS) and Highly Toxic Chemicals

• Highly toxic chemicals (e.g., inorganic cyanides, select carcinogens) must be stored in locked secondary containment.
• Minimize quantities to the absolute minimum necessary for active research.
• Maintain awareness of any required antidotes or specific medical countermeasures (e.g., calcium gluconate for hydrofluoric acid). See Cornell EHS guidance on Chapter 9: Particularly Hazardous Substances.

Physical Storage Practices

Cabinet and Shelf Organization

• Store larger bottles toward the back and smaller bottles in front where they are visible.
• Turn all labels facing outward so contents can be identified without moving containers.
• Apply the FIFO principle (First In, First Out): place newly received containers at the back and move older containers to the front. Rotation is based on receipt date, not remaining volume.
• Use shelves with anti-roll lips or equivalent restraint (heavy-gauge wire or twine barriers) to prevent bottles from falling.

Bench Tops and Fume Hoods

• Bench top storage must be kept to a minimum. Active reagents only; everything else returns to storage after use.
• Every chemical must have a designated storage location and must be returned to that location after use. Undesignated chemicals become orphan chemicals.

Floor Storage

• Chemicals must not be stored on the floor. Floor storage creates tripping hazards, increases spill risk, and impedes emergency egress.
• If floor placement is temporarily unavoidable, containers must be:
  • Placed in secondary containment (trays)
  • Located away from aisle spaces and egress paths
  • Moved to proper storage before personnel leave the area

Secondary Containment

• Secondary containment is required for all liquid chemical containers.
• Containment capacity must be at least 110% of the primary container volume (or the largest single container if multiple are in the same tray). This standard is consistent with EPA/RCRA 40 CFR 264.175 and is adopted as Cornell EHS best practice for all laboratory chemical storage.

Environmental Controls

• Do not store chemicals in direct sunlight or adjacent to heat sources (radiators, ovens, hot plates).
• Store chemicals requiring refrigeration only in units appropriate for that chemical class.

Inventory Minimization and Lifecycle Management

• Order only the quantity needed for current research. Smaller quantities reduce waste disposal costs, minimize hazard accumulation, and improve inventory accuracy.
• When ordering, first check the chemical inventory system to determine if the needed chemical already exists in your laboratory or in a neighboring lab willing to share.
• Check container expiration dates regularly. Dispose of expired chemicals promptly through EHS Hazardous Waste.
• Containers must remain closed when not in use. Open containers accelerate degradation, increase vapor exposure, and contribute to unintentional reactions.

Emergency Preparedness in Storage Areas

• Spill kits and spill control equipment must be immediately accessible in all areas where chemicals are stored or used. All personnel must know the location of spill kits and must have received training on their use.
• Emergency eyewash and shower equipment must be accessible within 10 seconds or 50 feet of travel from any point where hazardous chemicals are handled. 
• Be aware of any chemical-specific emergency response requirements (e.g., calcium gluconate availability for HF use areas).

If you need further information, call EHS at 607-255-8200, or send an e-mail to askEHS@cornell.edu.