The term "immediately dangerous to life or health" is defined by the US National Institute for Occupational Safety and Health as exposure to airborne contaminants that is "likely to cause death or imm
Personal protective equipment for IDLH conditions: pressure-demand supplied-air respirator equipped with a full facepiece in combination with an auxiliary pressure-demand self-contained breathing apparatus
Personal protective equipment for IDLH conditions: pressure-demand self-contained breathing apparatus with a full facepiece
A self-contained breathing apparatus is a respirator worn to provide an autonomous supply of breathable gas in an atmosphere that is immediately dangerous to life or health from a gas cylinder. They a
Immediately dangerous to life or health
…air through the gaps (which occur between the edges of the mask and the face sometimes). Textbook NIOSH recommended for use in IDLH conditions only pressure-demand self-contained breathing apparatus with a full facepiece, or pressure-demand supplied-air respirator equipped with a full facepiece in combination with an auxiliary pressure-demand…
Self contained breathing apparatus
1842 sketch of the Deane brothers' diving helmet, the first surface-supplied diving dress equipment in the world.
Siebe Gorman Savox in a coal mining museum
SCBA packs carried on a rack in a firetruck