OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at https://www.osha.gov.

July 11, 1991



SUBJECT:            Manufacturer Supplying Halon 1301 Systems for Fire and
                   Explosion Suppression

This memorandum is in response to your May 23 memorandum with enclosures on employer use of Halon 1301 for explosion and fire suppression in the workplace. Specifically, the following guidance is provided with respect to questions posed in the May 8 memorandum to you from the Pittsburgh Area Office.

The only OSHA standard which addresses explosion suppression systems is 29 CFR 1910.272(p)(8)(i) on grain handling facilities. However, use of Halon as an explosion suppression agent is not addressed by any OSHA standards. Fire suppression systems are covered by 29 CFR 1910.162. Apparently, the 1301 Halon system described in the internal Penn Champ Inc. memorandum of October 22, 1987, is installed to suppress explosions in conjunction with the use of pressure and radiant energy detectors, and to suppress fires in conjunction with the use of thermal detectors. Therefore, 29 CFR 1910.162, which covers fire suppression systems, is applicable to the latter combination. Workplace safety and health hazards associated with Halon 1301 systems used exclusively for explosion suppression are citable under section 5(a)(1) the OSH Act. For your information, the 1986 edition of NFPA 69 standard addresses "Explosive Prevention Systems".

Halon 1301 itself and associated products of combustion provide a potential hazard to employees. These hazards are addressed in A-1-6.1 of Appendix A of the NFPA 12A standard on Halon 1301 Fire Extinguishing Systems. The employer can meet OSHA standards for storage and handling of flammable and combustible liquids by means exclusive of explosion prevention systems, including the explosion suppression method employing Halon 1301.