What is a hazardous atmosphere?

According to OSHA, a “hazardous atmosphere” is an atmosphere that may expose employees to the risk of death, incapacitation, impairment of ability to self-rescue, injury, or acute illness from one or more of the following causes:
- Flammable gas, vapor, or mist in excess of 10 percent of its lower flammable limit (LFL)
- Airborne combustible dust at a concentration that meets or exceeds its LFL
Note: This concentration may be approximated as a condition in which the combustible dust obscures vision at a distance of 5 feet (1.52 meters) or less.
- Atmospheric oxygen concentration below 19.5% or above 23.5%
- Atmospheric concentration of any substance with an OSHA permissible exposure limit above the permissible exposure limit (PEL)
- Any other atmospheric condition that is immediately dangerous to life or health
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Written by Bob Henderson | President

Bob Henderson is President of GfG Instrumentation, Inc. in Ann Arbor, Michigan.Robert has been a member of the American Industrial Hygiene Association since 1992. He is an active member of the AIHA Real Time Detection Systems Technical Committee, and the AIHA Confined Spaces Committee. He is also a past chair of the Instrument Products Group of the International Safety Equipment Association. Robert has over 37 years of experience in the design, sale and marketing of atmospheric monitoring instruments used in confined space, industrial safety, and industrial hygiene monitoring applications.
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