What is the maximum permissible exposure limit (PEL) for asbestos over an 8-hour TWA?

The maximum permissible exposure limit (PEL) for asbestos is established to protect workers from the harmful effects of asbestos exposure, which is known to be a serious health hazard. The correct answer, which is 0.1 fibers per cubic centimeter (F/CC) over an 8-hour time-weighted average (TWA), is in line with the standards set by organizations such as the Occupational Safety and Health Administration (OSHA).

This limit reflects extensive scientific research demonstrating that prolonged exposure to asbestos fibers can lead to serious illnesses, including asbestosis, lung cancer, and mesothelioma. By establishing the PEL at 0.1 F/CC, regulatory bodies aim to minimize the risk of these health effects while allowing for necessary work processes that might involve asbestos.

The other listed options, such as 0.05 F/CC, 0.2 F/CC, and 0.5 F/CC, would either be too stringent or too lenient compared to the established standard. A limit of 0.05 F/CC would be more restrictive than current regulations, and limits of 0.2 F/CC or 0.5 F/CC would not provide adequate protection given the known risks associated with asbestos exposure