What is the limit of PAA?

Understanding PAA Exposure Limits in the Workplace

Peracetic acid (PAA) is a strong, pungent chemical commonly used in industrial sanitation, healthcare settings, and food processing due to its powerful antimicrobial properties. However, because it's highly reactive and potentially irritating to the eyes, skin, and respiratory system, safe handling is crucial.

Currently, the Occupational Safety and Health Administration (OSHA) does not have a specific permissible exposure limit (PEL) for PAA. This absence means employers must rely on guidance from other authoritative sources to ensure worker safety. One of the most widely referenced benchmarks comes from the American Conference of Governmental Industrial Hygienists (ACGIH).

ACGIH recommends a Threshold Limit Value (TLV) of 0.4 ppm as a 15-minute Short Term Exposure Limit (STEL). This means that workers should not be exposed to concentrations higher than 0.4 parts per million over a 15-minute period, even if the daily average appears low. This short-term limit is particularly important because PAA can cause immediate irritation at low levels, especially in poorly ventilated areas.

It’s also worth noting that, based on current data, ACGIH does not consider peracetic acid to be classifiable as a human carcinogen. While this is reassuring, it doesn’t eliminate the need for caution. Without an official OSHA standard, adherence to the ACGIH’s TLV remains one of the best practices for minimizing health risks.

Workplaces using PAA should implement proper ventilation, provide appropriate personal protective equipment (PPE), conduct regular air monitoring, and train employees on safe handling procedures—even in the absence of a federal mandate. Following expert guidelines like those from ACGIH helps protect workers while regulatory standards continue to evolve.