The National Institute for Occupational Safety and Health (NIOSH) is responsible for conducting research and making recommendations for the prevention of work-related injury and illness.
NIOSH is also directly responsible for several regulations.
NIOSH issues recommendations for respirator use. Industrial type approvals are in accordance to the NIOSH federal respiratory regulations 42 CFR Part 84: Approval of respiratory protective devices. Development of respirator standards are in concert with various partners from government and industry.
In the United States, the National Institute for Occupational Safety and Health defines the following categories of particulate filters
NIOSH APPROVED: N95
95% efficient against particulate aerosols free of oil. This respirator helps protect against certain particulate contaminants but does not eliminate exposure to or the risk of contracting disease or infection. Misuse may result in sickness or death.