ABC of Safety in the Biological Sciences
RESPIRATORS (Also see Face masks)
Respirators provide greater protection than a face mask and are available with gas, particulate, combined gas and particulate or self rescue filters.122 They should only be used in atmospheres of low toxicity which are not immediately harmful to life (up to 0.1% or 10 times the recommended Exposure Standard, whichever is lower). Half mask respirators should not be used where the contaminant is highly toxic or the contamination level is not known. Respirators available for use in medical laboratories are usually of the air purifying type as opposed to the supplied air devices (self-contained breathing apparatus).
Where respirators are in use it is recommended that:
Do not use a respirator for protection against gases and vapours from aniline, arsine, benzyl chloride, bromine, carbon monoxide, chlorine, formaldehyde, formic acid, hydrazine, hydrogen chloride, hydrogen peroxide (90%), phenol, pyridine or quinone (this is not a complete list of all such compounds).