What is considered an oxygen-deficient atmosphere?

An oxygen-deficient atmosphere is defined as one that contains less than 19.5% oxygen. This threshold is significant because it falls below the levels necessary for normal respiratory function in most people. At levels below this percentage, individuals may not receive adequate oxygen, posing serious health risks, including disorientation, unconsciousness, and potential suffocation.

Defining the critical threshold at 19.5% helps safety professionals set guidelines for working in confined spaces or environments where oxygen levels may be compromised, such as during asbestos abatement projects. This standard allows for the implementation of appropriate safety measures, including oxygen monitoring and the use of supplemental oxygen when necessary.

The less than 18% threshold would indeed indicate an oxygen-deficient atmosphere, but the more commonly accepted standard for an oxygen-deficient environment is the 19.5% level. Environments with no oxygen or fluctuating oxygen levels present different hazards and considerations, but they do not specifically reflect the designation of an oxygen-deficient atmosphere as defined in safety regulations and practices.