In April, the U.S. Occupational Safety and Health Administration (OSHA) released a new guidance document, Assigned Protection Factors (APF), which provides employers with vital information for selecting respirators for employees exposed to contaminants in the air. OSHA revised its existing respiratory protection standard in 2006 to add APFs and Maximum Use Concentration (MUC) provisions.

APFs indicate the level of respiratory protection a respirator or class of respirators is able to provide to workers. The higher the APF (5 to 10,000), the greater the level of protection provided to the user. The MUC represents the limit at which the class of respirator is expected to provide protection. Whenever a hazard’s exposure level exceeds the MUC, employers should select a respirator with a higher APF.

The APF and MUC are mandatory respirator selection requirements that can only be used after respirators are properly selected and are used in compliance with the entire standard. The respiratory protection standard requires fit testing, medical evaluations, specific training and proper respirator use. To read the new OSHA document, click here.

For more information, contact Stephanie Salmon, AFS Washington Office, at 202/842-4864 or This e-mail address is being protected from spam bots, you need JavaScript enabled to view it .