The National Institute for Occupational Safety and Health (NIOSH) is a research agency for the Centers for Disease Control (CDC) dedicated to worker safety and health. N95 respirators are awarded NIOSH approval when they have been evaluated in a laboratory and found compliant with the requirements laid on in Title 42, Code of Federal Regulations, Part 84. The manufacturer must also submit a quality plan that must be approved.  When using N95 respirators in a professional setting, you should always use N95 respirators that are NIOSH approved.