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Respiratory Protection — A Quick Review

Respirators play a key role in maintaining a safe work environment, and are among the most important pieces of protective equipment for working in hazardous conditions. Selecting the right respirator requires an assessment of all workplace operations, processes and environments. To choose the correct respirator, you must first be able to identify the hazard that exists, as well as any concentrations of airborne particles. This assessment should be conducted by experienced safety personnel or by an industrial hygienist. What follows is a summary of the OSHA Standard for Respiratory Protection, types of respirators, and a quick list of what employers should know about when implementing the standard in the workplace.

OSHA Standard 29 CFR 1910.134 States: In the control of those occupational diseases caused by breathing air contaminated with harmful dusts, fogs, fumes, mists, gases, smokes, sprays, or vapors, the primary objective shall be to prevent atmospheric contamination. This shall be accomplished as far as feasible by accepted engineering control measures (for example, enclosure or confinement of the operation, general and local ventilation, and substitution of less toxic materials). When effective engineering controls are not feasible, or while they are being instituted, appropriate respirators shall be used pursuant to this section. You can read the full OSHA Standard 29 CFR 1910.134 and related information here.

Types of Respirators

have been ruled out, the respirator selection process can begin. There are several different respirators for various hazard situations. The respirator you choose should provide protection against the hazard for which it was designed, in addition to being NIOSH approved.

Air-Purifying Respirators can be either filtering face piece, full-face or half masks with mechanical or chemical cartridges to filter dusts, mists, fumes, vapors or gases. They are available in three types: disposable, reusable, and disposable/reusable.

Filtering Facepiece Respirators are meant to be disposable, one-time use devices. These are used to filter out particulate matter only.

Disposable Air-Purifying Respirators are intended to be used once or until the cartridge expires. The cartridges are permanently attached and have no replacement parts.

Reusable Air-Purifying Respirators use both replaceable cartridges and parts.
Disposable/reusable Air-Purifying Respirators have few or no replaceable parts except cartridges.

Gas Masks are designed for slightly higher concentrations of organic vapors, gases, dusts, mists and fumes. The volume of sorbent used as the medium is higher than a chemical cartridge.

Powered Air-Purifying Respirators use a blower to pass the contaminated air through a filter. The purified air is then delivered into a mask or hood. They filter dusts, mists, fumes, vapors and gases, just like ordinary air-purifying respirators.

Air-purifying respirators cannot be used in oxygen-deficient atmospheres, which can result when another gas displaces the oxygen or consumption of oxygen by a chemical reaction occurs. Oxygen levels below 19.5% require either a source of supplied air or supplied-air respirator protection. Levels below 16% are considered to be unsafe and could cause death.

Supplied-Air Respirators provide the highest level of protection against highly toxic and unknown materials. Supplied air refers to self-contained breathing apparatuses (SCBAs) and air-line respirators. SCBAs have a limited air supply that is carried by the user, allowing for good mobility and fewer restrictions than air-line respirators.

Air-Line Respirators have an air hose that is connected to a fresh air supply from a central source. The source can be from a compressed air cylinder or air pump that provides at least Grade D breathing air.

Emergency Escape Breathing Apparatuses (EEBAs) provide breathing air for 5, 10 or 15 minutes depending on the unit. These are for emergency situations in which a worker must escape from environments immediately dangerous to life or health (IDLH).

  • Identify and evaluate respiratory hazards in the workplace.
  • Provide a medical evaluation to determine an employee’s ability to use a respirator.
  • Ensure fit testing occurs prior to initial use, whenever a different respirator facepiece is used, and at least annually thereafter.
  • Conduct evaluations of the workplace as necessary to ensure proper implementation of the program and consult with employees to ensure proper use.
  • Select and provide an appropriate respirator based on the respiratory hazard(s) to which the worker is exposed and workplace and user factors that affect respirator performance and reliability.
  • Select a respirator certified by the National Institute for Occupational Safety and Health (NIOSH), which must be used in compliance with the conditions of its certification.

Fit Testing

Employers are required to fit test any employee who needs to wear a respirator. This includes dust/mist respirators. Fit testing is a requirement of 29 CFR 1910.134.

Written Program

Anytime a respirator is used in the workplace, a written program must be established. A program outlines very specific procedures for respirator use in all situations. The program can vary in format, but must contain specific information on topics ranging from buying a respirator to employee training.

Ongoing workplace monitoring ensures that employees are adequately protected. Any change in the workplace operations may change the levels of contaminants or introduce new hazards. If a change occurs, the entire respirator program should be re-evaluated to determine its effectiveness.

One exception, is that employers are not required to include in a written respiratory protection program those employees whose only use of respirators involves the voluntary use of filtering facepieces. Voluntary use guidelines are found in 29 CFR 1910.134 Appendix D.

Commonly Asked Questions

QWhat are nuisance levels? ANuisance levels refer to concentrations of contaminants below the OSHA permissible exposure level. QWhat is the shelf life of a cartridge? ACartridges have an indefinite shelf life, unless otherwise specified by the manufacturer. QWhat does HEPA stand for? AHigh Efficiency Particulate Absolute. HEPA filters remove from the air 99.97% or more of particles having a diameter of 0.3 microns.


Respiratory Protection, 29 CFR 1910.134.
Air Contaminants Standard, 29 CFR 1910.1000.

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