According to OSHA regulations, what is the maximum time-weighted concentration at which 95% of exposed, healthy adults suffer no adverse effects over a 40-hour work week?

The maximum time-weighted concentration that ensures 95% of exposed, healthy adults suffer no adverse effects during a 40-hour work week is referred to as the Permissible Exposure Limit (PEL). PELs are established by the Occupational Safety and Health Administration (OSHA) as legal limits on the amount or concentration of a substance in the air in the workplace. These limits are based on extensive research and are designed to protect workers’ health by ensuring that exposure does not cause significant risk of harm over a standard work week.

In contrast, Lethal Dose (LD50) refers to the amount of a substance that is sufficient to kill 50% of a test population, which is not relevant for determining safe exposure limits for healthy workers. Radiation Absorbed Dose (RAD) is a unit of measurement for ionizing radiation exposure, which is specific to radiation and not a broad standard for chemical exposures in the workplace. Parts Per Million/Parts Per Billion are units of measurement that express low concentrations of substances, but they do not represent a regulatory limit like a PEL does.

Therefore, the PEL is the correct answer as it specifically addresses workplace safety standards established to prevent adverse health effects in employees exposed to hazardous substances.