Reference

What Happens If a Respirator Doesn't Fit: A respirator that does not seal properly against the face stops working as rated. Fit failure collapses the assigned protection factor (APF) - a half-face respirator with an APF of 10 can deliver as little as 2× protection if the face seal leaks.

Can You Reuse an N95: N95 filtering facepiece respirators (FFRs) are designated as single-use devices under NIOSH's 42 CFR Part 84 approval system. NIOSH does not approve any N95 for routine reuse.

NIOSH vs. OSHA Explained (2026 Guide): NIOSH (National Institute for Occupational Safety and Health) is a research and certification agency within the CDC that approves PPE and sets recommended exposure limits.