What designation is included in respirator numbers that are tested and certified by NIOSH or MSHA?

• A. TC
• B. NS
• C. OSHA
• D. MSHA

Answer: (A)

Respirator numbers that have been tested and certified by NIOSH (and recognized by MSHA) include the prefix TC in the approval number. This TC prefix stands for the official testing and certification that the device has undergone and met the required standards, and you’ll typically see something like TC-21C-XXXX on the label. The other options aren’t prefixes used to mark these approval numbers: NS isn’t a standard designation, OSHA is the regulatory agency rather than a label prefix, and MSHA is an agency name, not the numeric prefix used in approvals. So the best answer is the TC prefix because it directly identifies the NIOSH/MSHA-tested and certified respirator designation.