This type of respirator can be half-mask or full-face mask. They have replaceable cartridges to remove chemicals from the air; different types of cartridges protect against different materials. Cartridges are color-coded, based on the protection they offer. For example, cartridges that protect against organic vapors such as pesticide vapors are black, with “organic vapors” written on the label. (Pesticides are organic compounds; they consist of carbon molecules.) A pink and black cartridge removes pesticide dusts, mists, and fine particles along with organic vapors (such as pesticides). See TC Numbers and Cartridge Colors for more information on cartridge colors. All cartridges must be labeled with the appropriate NIOSH-approval label. Replacement cartridges, parts and other accessories for respirators must be made specifically for that respirator make and model.
The half-mask respirator covers the nose and mouth. If the pesticide label requires eye protection, you must wear goggles or another type of eye protection in addition to the half-mask respirator. A full-face respirator protects the eyes, nose, and face.
The chemical cartridge respirator is meant to protect against light concentrations of chemicals, such as when mixing pesticides outdoors or applying a pesticide product diluted with water or another carrier. A pre-filter cartridge also provides protection from particulate matter. The pesticide label will indicate if the chemical cartridge respirator is appropriate, and the type of cartridge required. The cartridge respirator should not be used if the pesticide product does not have good warning properties, meaning the pesticide cannot be tasted or smelled. This is because one of the warning signs that a cartridge is spent or the respirator is not working correctly is tasting or smelling the chemical while wearing the respirator.
Do not wear a chemical cartridge respirator in an area considered immediately dangerous to life or health (IDLH). This is an area where dangerous gases can build up, creating a deadly atmosphere that can kill in seconds. Examples are a manure pit or silo with gases; a chemical cartridge respirator will not provide adequate protection in these situations.
From CDC/OSHA