OSHA addresses Toxic and Hazardous Substances in the “Z” tables (29 CFR 1910 Subpart Z-Toxic and Hazardous Substances). When questions arise related to hazardous materials, NFPA 400-Hazardous Materials Code can provide some additional technical information.
One of the most frequent questions we are asked about hazardous materials is what quantity can be used or stored. NFPA 400, the Hazardous Materials Code, breaks this down by hazard, by occupancy type, as well as whether it is in storage or in use.
There are several tables in NFPA 400 that provide Maximum Allowable Quantities (MAQs) of hazardous materials per control area. The MAQs are a threshold quantity, and if the quantities used or stored are under the MAQ, then no special construction features are required.
Certain hazardous material categories are not regulated by NFPA 400 but are incorporated by reference for informational purposes. For example, MAQs for flammable liquids from NFPA 30 and MAQs for gases and cryogenic fluids from NFPA 55 are included in the NFPA 400 MAQ tables.
The MAQs are not an absolute maximum. Once the MAQ is exceeded, additional controls will need to be put in place to make the facility safe and code compliant. Either the materials need to be separated into multiple control areas, or provisions for protection levels need to be applied (like automatic sprinklers, spill control, secondary containment, and separation from other occupancies).
Ready to check that you are within the MAQ or have the necessary controls put in place? Access the latest edition of NFPA 400 for free at www.nfpa.org/400.
Staff Liaison: Laura Moreno