OSHA requires respiratory protection to be worn whenever work is being conducted in hazardous atmospheres. Although different respirators are required in different atmospheric situations, in all cases training must be provided to employees using such devices. All required respirators must be approved by NIOSH.
OSHA outlines different types of respiratory protection available and their proper usage:
Single-strap dust masks – These masks usually are not NIOSH-approved and are not for use as protection from hazardous atmospheres. They can, however, be used to block pollen and other allergens.
Approved filtering facepieces (dust masks) – These masks do not provide protection against dangerous gases or vapors, and are not for use when working with lead or asbestos. Dust masks are helpful for blocking dust, mist and welding fumes.
Half-face respirator – These masks can be used to protect against vapors, gases, dust and welding fumes. Mask filters and cartridges must match contaminants and must be changed periodically.
Full-face respirator – This offers the same protection from vapors and gases as the half-face respirator, but has a faceshield that protects from irritants and contaminants. Mask filters and cartridges must match contaminants and be changed periodically.
Loose-fitting powered air purifying respirators – These respirators use a battery-powered fan to pull air through filters and circulate throughout the helmet or hood. Filters and cartridges must match contaminants and be changed periodically.
Self-contained breathing apparatus – These apparatus have their own air tank and are used in situations in which the work atmosphere is or may become oxygen-deficient or is otherwise immediately dangerous to life and health.