With some exceptions, air purifying respirators can be used for most air contaminants. Respirators for gases and vapors must either be equipped with an ESLI or the employer must implement a canister or cartridge change schedule.
Air purifying respirators must not be worn in atmospheres unknown and/or IDLH, atmospheres in oxygen deficient atmospheres, or in situations
where the employer cannot prevent the canister or cartridge from becoming saturated. They also cannot be worn if prohibited by the respirator requirements for substance specific standards (e.g., methylene chloride) or other OSHA standards (e.g., abrasive blasting per 29 CFR 1910.94, Ventilation). Also, respirator manufacturers have lists of contaminants for which air purifying respirators are not recommended.
