Standard Interpretations - Table of Contents
• Standard Number: 1910.134(b); 1910.134(g)(4); 1910.155(c)(26); 1910.156(a)(2)

July 8, 2002

Mr. Robert Weilding
23115 McGuire Road
Wilmington, Illinois 60481

Dear Mr Weilding:

Thank you for your April 3 letter to the Occupational Safety and Health Administration (OSHA) regarding fire brigades and the use of respirators. This letter constitutes OSHA's interpretation only of the requirements discussed and may not be applicable to any question not delineated within your original correspondence. Your questions are restated below, followed by our replies.

Question: If there is visible smoke present during a structure/building fire, would responders be required to wear SCBA units within the contaminated atmosphere as stated in 29 CFR 1910.134(g)(4)?

Reply: The presence of visible smoke itself does not trigger a requirement to wear any particular type of respirator. Fires that have not progressed beyond the incipient stage, such as stove grease fires, might be extinguished without the responders needing to wear any respiratory protection. Larger fires, which have progressed beyond the incipient stage, would require SCBAs for entry.

Question: If responders are required to wear SCBAs, would this be considered beyond the incipient stage fire as defined in 29 CFR 1910.155?

Reply: An incipient stage fire is defined as a fire that is in the initial or beginning stage and can be controlled or extinguished by portable fire extinguishers, Class II standpipe, or small hose systems without the need for protective clothing or breathing apparatus. Wearing more protective equipment than necessary for that fire, such as an SCBA, would not upgrade the class of fire.

Question: If responders are required to extinguish fires and/or rescue people, and there is visible smoke and the responders are wearing SCBAs, is this considered interior structural fire fighting as stated in