2-30. APPROVING AGENCIES
At one time, the US Bureau of Mines was the governmental agency responsible
for approval of respirators. The NIOSH and the Mine Safety and Health Administration
(MSHA) have assumed this responsibility. Manufacturers of respirators are to submit
respirators to NIOSH for testing and certifying. When a respirator is found to be
satisfactory for use against a specific contaminant and concentration, NIOSH issues it a
"TC" number indicating that it has been "tested and certified" with Federal Law.
Thereafter, it must be used as a unit as certified. If it requires any replacement parts,
they must be replaced by parts identical to those being replaced.