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Respiratory Protection and the selection of respirators

An estimated 5 million workers are required to wear respirators in 1.3 million workplaces throughout the United States. Respirators protect workers against insufficient oxygen environments, harmful dusts, fogs, smokes, mists, gases, vapors, and sprays.


These hazards may cause cancer, lung impairment, diseases, or death. Compliance with the OSHA Respiratory Protection Standard could avert hundreds of deaths and thousands of illnesses annually.

Respirators protect the user in two basic ways. The first is by the removal of contaminants from the air. Respirators of this type include particulate respirators, which filter out airborne particles, and air-purifying respirators with cartridges/canisters which filter out chemicals and gases. Other respirators protect by supplying clean respirable air from another source. Respirators that fall into this category include airline respirators, which use compressed air from a remote source, and self-contained breathing apparatus (SCBA), which include their own air supply.


Each type of respirator can come in several varieties, each with its own set of cautions, limitations, and restrictions of use. Tight fitting respirators require fit testing to ensure an adequate fit to the face, and cannot be used with facial hair. Certain escape respirators use a nose clip and mouthpiece, which is clenched between your teeth, similar to a snorkel. Some respirators prevent the user from talking while others have speaking diaphragms or electronic communication devices. Every respirator contaminated with hazardous chemicals should be cleaned and decontaminated or disposed of properly.

All respirators require training in order to be properly used. Sometimes you can practice using your own respirator. Some escape respirators come in a package that must remain sealed until use, so you need to be trained using a special “practice” version. Training is extremely important in regard to the storage, maintenance, use, and disposal of the respirator. This information is provided by the supplier of the respirator (i.e., seller, distributor, or manufacturer). If you do not use a respirator correctly, it is very likely that it will not adequately protect you and may even hurt you.

Not everyone can wear a respirator. Breathing through a respirator is more difficult than breathing in open air. People with lung diseases, such as asthma or emphysema, elderly people, and others may have trouble breathing. People with claustrophobia may not be able to wear a full face piece or hooded respirator. People with vision problems may have trouble seeing while wearing a mask or hood (there are special masks for people who need glasses). Employees must be medically evaluated before assigned to use a respirator.

Considerations for respirator selection

  • What protection (which chemicals and particles, and at what levels) does the respirator provide?
  • Is there more than one size?
  • Which size should I use?
  • How do I know if the gas mask or respirator will fit?
  • What type of training do I need?
  • Are there any special maintenance or storage conditions?
  • Will I be able to talk while wearing the respirator?
  • Does the hood restrict vision or head movement in any way?
  • Can I carry the device in the trunk of my automobile?
  • Is a training respirator available?

Exposure Assessment to select an appropriate respirator
The employer must conduct an exposure assessment to determine the type and amount of hazardous exposure. Employers must characterize the nature and magnitude of employee exposures to respiratory hazards before selecting respiratory protection equipment. The employer is required to identify and evaluate the respiratory hazard(s) in the workplace. Employers must make a "reasonable estimate" of the employee exposures anticipated to occur as a result of those hazards, including those likely to be encountered in reasonably foreseeable emergency situations, and must also identify the physical state and chemical form of such contaminant(s). The final rule does not specify how the employer is to make reasonable estimates of employee exposures for the purposes of selecting respirators.

The employer must understand and consider the “Assigned Protection Factors” of each type of respirator to be selected. The assigned protection factor (APF) of a respirator reflects the level of protection that a properly functioning respirator would be expected to provide to a population of properly fitted and trained users. For example, an APF of 10 for a respirator means that a user could expect to inhale no more than one tenth of the airborne contaminant present. This calculation would then be repeated for each contaminant present.

The employer must also understand and consider the “Maximum Use Concentration” of each type of respirator to be selected. The maximum use concentration (MUC) is the maximum concentration of hazardous substance or air contaminants outside the respirator, the employee is allowed to be exposed to when measured outside the respirator. Employers must not apply MUCs to conditions that are immediately dangerous to life or health (IDLH); instead, they must use respirators listed for IDLH conditions. Also, the respirator selected shall be appropriate for the concentration, chemical state and physical form of the contaminant.

For example, consider a disposable half face piece respirator for a stainless steel welder whose highest exposure is 25 micrograms per cubic meter (μg/m3) of hexavalent chromium as an 8-hour average. This respirator class has an APF of 10, and the “Permissible Exposure Limit” (PEL) for hexavalent chromium is 5 micrograms per cubic meter (μg/m3). In this case the maximum concentration of hexavalent chromium a welder could safely work in with this respirator is 10 x 5 = 50 μg/m3. Since the actual exposure (25 μg/m3) is less than the calculated maximum, this would be an appropriate respirator selection.

Fit Testing

In addition, the employer is required to develop and implement a written respiratory protection program with required worksite-specific procedures and elements for required respirator use. The program must be administered by a suitably trained program administrator. The respiratory protection program must include worksite-specific procedures. The program must be updated as necessary to reflect those changes in workplace conditions that affect respirator use. The programs must also include procedures for selecting respirators for use in the workplace; medical evaluations of employees required to use respirators; fit testing procedures for tight-fitting respirators; procedures for proper use of respirators in routine and reasonably foreseeable emergency situations; procedures and schedules for cleaning, disinfecting, storing, inspecting, repairing, discarding, and otherwise maintaining respirators; procedures to ensure adequate air quality, quantity, and flow of breathing air for atmosphere-supplying respirators; training of employees in the respiratory hazards to which they are potentially exposed during routine and emergency situations; training of employees in the proper use of respirators, including putting on and removing them, any limitations on their use, and their maintenance; and Procedures for regularly evaluating the effectiveness of the program.

As you can see, careful considerations and planning are required to implement and maintain an effective respiratory protection program in the workplace. For more information about respiratory protection, exposure assessments, respiratory protection programs and other training resources, please visit the SafetyFlorida Consultation Program website at www.usfsafetyflorida.com and request a consultation visit.