Permissible Exposure Levels: In the provided guidelines, what is the 8-hour PEL value?

• A. Excursion Limit (30 minutes) = 1.0 f/cc
• B. 8 Hr PEL = 0.1 f/cc
• C. MAAL for ambients or clearance = 0.01 f/cc
• D. TEM PEL is 70 structures

Answer: (B)

The 8-hour PEL is the allowable average concentration of fibers a worker can be exposed to over an entire 8-hour shift, expressed as fibers per cubic centimeter (f/cc). For asbestos measured by PCM, this long-term exposure limit is 0.1 f/cc, which is designed to protect workers from health effects associated with chronic exposure.

There is also a short-term exposure limit, which is higher (1.0 f/cc) but only applies to a 30-minute period to address brief spikes in concentration. The other figures listed (0.01 f/cc for ambient clearance and a TEM-based count of 70 structures) refer to different measurement contexts or methods and are not the 8-hour PEL for typical PCM-based asbestos monitoring.