Regulators & Standards Bodies

NIOSHNational Institute for Occupational Safety and Health

The research agency, part of the CDC, that studies workplace hazards and recommends occupational-safety standards.

Reviewed June 2026 by Enterprise Health

Key facts

  • The research arm for occupational safety & health, part of the CDC.
  • Publishes Recommended Exposure Limits (RELs) and certifies respirators (e.g., N95).
  • Researches the science that often becomes OSHA standards.

What it means

Unlike OSHA, which regulates, NIOSH researches. It develops recommended exposure limits (RELs), certifies respirators (the familiar N95 designation is a NIOSH approval), runs the spirometry and hearing-conservation training that occupational programs rely on, and publishes the science that often becomes the basis for OSHA standards. Occupational-health teams reference NIOSH criteria when designing medical-surveillance and exposure-monitoring protocols.

Frequently asked

What's the difference between NIOSH and OSHA?

NIOSH researches and recommends; OSHA regulates and enforces. NIOSH develops RELs, certifies respirators and runs surveillance training, while OSHA sets the legally enforceable standards.

What does the NIOSH approval on a respirator mean?

It means NIOSH tested and certified the respirator to a performance class — the familiar 'N95' designation is a NIOSH approval. Occupational programs specify NIOSH-approved respirators in their respiratory-protection plans.

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