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Types of Respirators

The employer shall select and provide an appropriate respirator based on the respiratory hazard(s) to which the worker is exposed.  The respirator selected shall be appropriate for the chemical state and physical form of the contaminant.  The employer shall select a NIOSH-certified respirator which shall be used in compliance with the conditions of its certification.

Dust Masks and Filter Respirators

Particulate respirators capture particles in the air such as dusts, mists and fumes. They do not protect against gases or vapors. They generally become more effective as particles accumulate on the filter and plug spaces between the fibers. Filters should be replaced when a user finds it difficult to breathe through them. 

Particulate respirators are the simplest, least expensive, and least protective of the respirator types available.  These respirators only protect against particles (e.g., dust).  They do not protect against chemicals, gases, or vapors, and are intended only for low hazard levels.  The commonly known “N-95” filtering face piece respirator or “dust mask” is one type of particulate respirator, often used in hospitals to protect against infectious agents. Particulate respirators are “air purifying respirators” because they clean particles out of the air as you breathe.

Chemical Cartridge Respirators

Cartridge and canister respirators are normally used when there are only hazardous gases and vapors in the air. They use chemical filters (called cartridges or canisters) to remove dangerous gases and vapors. They do not protect against airborne particles. They are designed to protect against specific gases or vapors. They only provide protection as long as the filter's absorbing capacity is not depleted. The service life of the filter depends on many factors and can be estimated through various methods. Cartridges may be assigned a color designating the type of contaminant they filter. 

Contaminant Color
Acid gases White
Hydrocyanic acid gas White with 1/2 inch green stripe completely around the canister near the bottom
Chlorine gas White with 1/2 inch yellow stripe completely around the canister near the bottom
Organic vapors Black
Ammonia gas Green
Acid gases and ammonia gas Green with 1/2 inch white stripe completely around the canister near the bottom.
Carbon monoxide Blue
Acid gases and organic vapors Yellow
Hydrocyanic acid gas and chloropicrin vapor Yellow with 1/2 inch blue stripe completely around the canister near the bottom.
Acid gases, organic vapors, and ammonia gases Brown
Radioactive materials except tritium and noble gases Purple (magenta)
Pesticides Organic vapor canister plus a particulate filter
Multi-contaminant and chemical, biological, radiological, and nuclear agent (CBRN) Olive
Any particulates - P100 Purple
Any particulate - P95, P99, R95, R99, R100 Orange
Any particulates free of oil - N95, N99, N100 Teal