Proper chemical storage is essential to maintaining a safe laboratory environment, preventing hazardous reactions, and ensuring compliance with federal and state regulations to reduce risk of fire, chemical incompatibilities, and accidental exposure. This guidance provides a framework for safely storing chemicals based on hazard class and compatibility. All laboratories are responsible for ensuring that chemicals are properly labeled, securely stored, and segregated to prevent incompatible interactions. Storage practices must also support safe handling throughout the chemical lifecycle.
The chemical compatibility framework used in this guidance is based on six primary hazard categories: Flammables, Oxidizers, Corrosives (Acids and Bases), Reactives, Toxic/Chronic Hazards, and Compressed Gases. These categories form the basis for the storage requirements and segregation rules outlined in the table below.
General Storage Principles (Regardless of Chemical Classification)
- Maintain compatible chemical segregation at all times
- Store chemicals below eye level when possible
- Keep containers closed when not in use
- Use secondary containment where spill risk exists
- Ensure clear labeling (GHS-compliant)
- Do not store chemicals in fume hoods except for active use
- Inspect containers routinely for integrity and expiration (especially peroxide formers)
Chemical Compatibility and Storage Guidance
| Chemical Class | Storage Requirements | Must Be Segregated From |
| Flammable Liquids (e.g., acetone, ethanol, toluene) | Approved flammable storage cabinet (NFPA 30 compliant); grounded cabinets for large volumes | Oxidizers, ignition sources, strong acids (in large quantities) |
| Oxidizers (e.g., nitrates, perchlorates) | Cool, dry, dedicated oxidizer cabinet | Flammables, organics, reducing agents, combustibles |
| Acids – Inorganic (e.g., HCl, H2SO4, HNO3) | Corrosives cabinet with secondary containment | Bases, cyanides, sulfides, oxidizers (especially nitric acid separation) |
| Acids – Organic (e.g., acetic acid, formic acid) | Corrosives cabinet, separate from inorganic acids when incompatibility or reactivity hazard is present. | Oxidizers, bases, nitrates |
| Bases (Caustics) (e.g., NaOH, KOH, ammonium hydroxide) | Corrosives cabinet with spill containment | Acids, metals, organic halides |
| Water-Reactive Chemicals (e.g., sodium metal, lithium aluminum hydride) | Dry, inert atmosphere if required; desiccator or specialized cabinet | Water, aqueous solutions, acids, oxidizers |
| Pyrophorics (e.g., organolithium reagents | Airtight containers, inert atmosphere (glovebox or Schlenk techniques) | Air, moisture, oxidizers |
| Toxic Chemicals (acute/chronic) | Secure, labeled storage; may require locked cabinets | Incompatible reactives |
| Phenolic Compounds (e.g. Phenol, Cresols, Substituted Phenols) | Dedicated toxic/corrosive storage cabinet or segregated bin system with secondary containment; tightly sealed containers; cool, dry storage conditions; restricted access recommended for concentrated phenol. | Strong inorganic acids (e.g., HCl, H₂SO₄, HNO₃); oxidizers; strong bases; general corrosive acid storage groupings. |
| Peroxide-Forming Chemicals (e.g., ethers, THF, dioxane, hydrogen peroxide > 30%) | Amber bottles, light-protected storage; date opened; periodic testing | Heat, contamination sources, oxidizers |
| Compressed Gases | Cylinders shall be secured upright using chains, straps, or racks. Protective valve caps shall be installed when cylinders are not connected for use. Flammable gas cylinders and oxidizing gas cylinders shall be stored in separate designated storage locations or physically segregated by approved barriers. | Flammable gases; oxidizing gases; incompatible reactive gases (e.g., chlorine with ammonia); ignition sources; incompatible chemical environments based on SDS hazard class. |
| Cryogens (e.g., liquid nitrogen) | Ventilated storage; approved dewars | Enclosed spaces without ventilation; incompatible materials |
| Carcinogens / Reproductive toxins | Designated, labeled, restricted access storage | General reagents; uncontrolled access areas |
| PFAS Compounds (Per-and Polyfluoroalkyl Substances) | PFAS must be stored only in compatible, chemically resistant containers such as high-density polyethylene (HDPE), polypropylene, or fluoropolymer-lined containers with tight-sealing, chemically compatible caps. Glass may be used where appropriate for analytical samples. Containers must be clearly labeled, leak-resistant, and placed within secondary containment trays. Bulk liquids and contaminated solids (e.g., soils, absorbents) must not be stored in food-grade containers (e.g., milk jugs), thin-walled retail plastics, or unsealed transport totes. | Oxidizers; strong acids; strong bases; incompatible reactive chemicals; general organic solvent storage areas; food-grade or non-laboratory-grade containers and waste handling systems. |
| General Laboratory Chemicals | Compatible segregation in standard chemical shelving | Incompatible hazard classes above |
