What Is A PEL?

The Occupational Safety and Health Administration (OSHA) bases its air quality standards on “permissible exposure limits,” or PEL’s. A PEL is a maximum amount of substance in the air that a worker can be exposed to over the course of an eight-hour shift. The exposure is measured as a time-weighted average (TWA). If an exposure goes over the PEL, penalties can ensue.

Adhering to PELs is important for many reasons. First, workers’ health depends on it. PEL’s are set based on evidence of health effects, and they represent the maximum safe exposure. In fact, OSHA has said that many of today’s PEL’s might be outdated. Many of OSHA’s PEL’s were set in the early days of the agency, and it is possible that stricter limits are needed to adequately protect workers. The agency advises that employers err on the side of caution when setting air quality goals. Here are PEL’s for some common industrial contaminants:

• Cadmium: 0.005 mg/m3
• Hexavalent chromium: 0.005 mg/m3
• Lead: 0.05 mg/m3
• Nickel: 1.0 mg/m3
• Manganese: 5.0 mg/m3