When properly fitted, helps provide respiratory protection from certain organic vapors and particulates, chlorine, hydrogen chloride, sulfur dioxide, chlorine dioxide, hydrogen sulfide (escape only), ammonia, methylamine, formaldehyde or hydrogen fluoride at concentrations up to 10 times the Permissible Exposure Limit (PEL). Do not use in environments that are immediately dangerous to life or health (IDLH). OSHA requires that gas-proof goggles be worn with half facepiece respirators when used against formaldehyde.