The following is a notice from the Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, and NIOSH:
"Worker safety can be compromised by using replacement component parts or accessories that are not NIOSH-approved for the specific respirator. Although NIOSH-approved respirators are comprised of various component parts, they are approved as a complete unit. The use of components which are not part of the approved assembly results in a respirator that has not been evaluated and certified by NIOSH. This applies not only to parts supplied by other vendors, but also to those supplied by the original equipment manufacturer, if the component parts have not been evaluated by NIOSH as part of the respirator. Unevaluated respirator assemblies may not function at the expected level of protection, putting the worker at risk for exposure to airborne hazards. Manufacturers’ quality systems confirm replacement components for use, fit and function, and ensure reliability and repeatable performance. NIOSH issues certificates of approval for specific and complete respirator assemblies. The approval is granted after the respirator has been evaluated, tested, and found to be in compliance with all of the applicable requirements of the NIOSH regulations in Title 42, Code of Federal Regulations, Part 84. Manufacturers are required to have an effective quality assurance program that meets or exceeds the standard, and to control the important aspects of the components and their assemblies."