The National Institute for Occupational Safety and Health (NIOSH) is in the process of developing new regulations for several types of respirators, in particular, for closed circuit self-contained breathing apparatus (CC-SCBA), supplied-air respirators (SARs) and powered air-purifying respirators (PAPR or PAPRs). Each of these proposals not only updates existing industrial requirements, but also has a chemical, biological, radiological and nuclear (CBRN) component.

The largest impact of the new regulations will be for the PAPR category, where a large amount of change is occurring and several new requirements are being considered. In the present respirator regulations (Title 42, Code of Federal Regulations, Part 84 — also known as 42 CFR 84), there presently is no subpart specifically for PAPRs.

Most users believe PAPRs to be positive-pressure units. But in fact, many existing models can and do go negative during inhalation and the user may or may not be aware of this, especially during high work rates when one's mind is focused on the task at hand. With the new requirements that NIOSH is proposing, PAPRs will have to remain positive during NIOSH testing. They will be tested on a machine that simulates breathing and the PAPRs will be required to monitor and warn users when or if the inside air pressure goes below ambient. PAPRs also will be required to monitor battery life and warn when the battery becomes low.