ABSTRACT
Respirators are considered the last line of defense in protecting employees from harmful dusts, mists, fumes, gases and vapors. Respirator standards published by Occupational Safety and Health Administration (OSHA) and American National Standards Institute (ANSI) require that atmospheric hazards preferably be controlled by substituting less toxic materials or by providing engineering controls such as ventilation. Respirators must fit properly and users must be provided with an opportunity to wear them in a test atmosphere. If atmosphere-supplying equipment such as self-contained breathing apparatus or air-line devices is used, the breathing air must meet specific criteria for quality. Air-supplied respirators must be provided with an adequate supply of air if they are to provide their rated level of protection. Quantitative fit-testing methods indicate the level of protection afforded under controlled conditions, and actual workplace conditions may result in a lower level of protection. Respirator users should receive a comprehensive medical examination to determine if they are physically capable of wearing a respirator.
