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.

March 24, 1987

Ivan W. Russell, Director
Occupational Safety and
Health Division
State of Minnesota
Department of Labor
and Industry
444 Lafayette Road
St. Paul, Minnesota 55101

Dear Mr. Russell:

This is in response to your letter of February 13, concerning the acceptance of a closed-circuit self-contained breathing apparatus (CCSCBA) for fire-fighting. Your concern is that there is an apparent contradiction between policies of the Occupational Safety and Health Administration (OSHA) and the National Institute for Occupational Safety and Health (NIOSH).

In 1983, OSHA issued a memorandum which recognized two CCSCBAs manufactured by the Biomarine Industries; namely, the Biopak 60P and the Biopak 30P, as positive pressure devices. OSHA accepted these devices for fire-fighting. However, NIOSH's position is that only the Biopak 240P is certified as a positive pressure device with the following use limitation:

"Do not use this apparatus where there is direct exposure to open flames or in high radiant heat."

The reason for OSHA's acceptance of the Biopak 60P and Biopak 30P for fire-fighting is that these rebreathers are positive pressure devices based on test results performed by the Lawrence Livermore and Los Alamos National Laboratories as well as NIOSH. Unfortunately, the respirator certification regulations, 30 CFR 11, did not recognize the positive pressure CCSCBAs before November 1985. Before that time, NIOSH could not certify these devices as positive pressure rebreathers. The Biopak 60P has a service life of one hour, however, the service life for NIOSH's certified one-hour open-circuit SCBA can only deliver 40 to 45 minutes. Long service life SCBA's are needed for certain fire situations such as in high rise buildings and inside long tunnels where the open-circuit devices would not provide a sufficient margin of safety.

NIOSH's concern is that an oxygen rebreather may become a potential fire hazard when it is used in direct exposure to flame or high radiant heat. Since only a very small amount of oxygen is leaked through the facepiece seal, this quantity may not be significant to present a hazard unless the facepiece is dislodged from the face of the wearer. In this case the wearer would be overcome by the large quantity of toxic substances in the combustion products. Oxygen rebreathers have been used by the Navy in submarines for years with no serious problems being reported.

The issue of safety of the CCSCBAs in a fire environment was a major issue of OSHA's rulemaking on fire brigades. There was insufficient information to demonstrate that a CCSCBA could become a potential safety hazard in the fire environment. OSHA recognized the lack of data in this area and has jointly funded a study with the California Division of Occupational Safety and Health (CalOSHA) on this problem. The Lawrence Levermore National Laboratory (LLNL) is performing the study; the results will be available in the near future. As a part of this study, the LLNL sponsored a symposium on the role of closed-circuit breathing apparatus in structural fire-fighting in October 1984. Several speakers, who described their experience with the positive pressure CCSCBAs indicated that there were no serious incidents. The transcripts of their speeches are enclosed for your information.

We will review the LLNL data and restate our position on the acceptance of the positive-pressure closed-circuit self-contained breathing apparatus when the LLNL study becomes available. In the meantime, we maintain our position as stated in the 1983 memorandum.


Edward J. Baier
Directorate of Technical Support