http://www.cdc.gov/nasd/docs/d000101-d000200/d000111/d000111-s.html
This document also available in Spanish
National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention
This fact sheet delineates the procedures of the proper care, storage, and inspection of respirators. The fact sheet considers the proper fit for respirators and explains that they should be used for protection and is not a source of oxygen supply.