OSHA requires the use of respiratory protection whenever work is conducted in hazardous atmospheres. Different respirators are required in different atmospheric situations, but in all cases, training must be provided to employees using these devices. All required respirators must be NIOSH-approved.
OSHA outlines the different types of respiratory protection available and their proper usage:
Single-strap dust masks: These are usually not NIOSH-approved and not for use as protection from hazardous atmospheres. However, they can be used to block pollen or other allergens.
Full-face respirator: These offer the same protection from vapors and gases as the half-face respirator, but have a face shield that adds eye and face protection from irritants and contaminants. Mask filters and cartridges must match contaminants and be changed periodically.
Approved filtering face pieces (dust masks): These 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, mists and welding fumes.
Half-face respirator: These can be used to protect against most vapors, gases, dust and welding fumes. 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: SCBAs have their own air tank and are for use in situations where the atmosphere is oxygen deficient or otherwise immediately dangerous to life and health.