The product-audit program obtains targeted respirators through normal commercial channels and tests the devices to insure they continue to perform to the applicable standard.  The product-audit program is focused on filtering-facepiece respirators because these respirators comprise the bulk of NIOSH approvals and they are the most commonly used respiratory-protective product in the workplace. 

Long Term Field Evaluations are directed at maintaining long term effectiveness in the self-contained, closed-circuit, escape breathing apparatus used to protect the nation's coal miners in the event of an underground explosion or fire. The Certified Product Investigation Process is the corrective instrument of the respirator approval process, investigating potential issues reported on respirator models currently on the market. The Technology Evaluation Branch also conducts a limited applied-engineering evaluation of respirator test methods and respirator technology to support the certification function.