What is OSHA's standard for hydrogen sulfide (H2S) exposure?

The correct choice reflects OSHA’s permissible exposure limit (PEL) for hydrogen sulfide (H2S) in the workplace, which is set at 20 parts per million (ppm) for an 8-hour workday. This standard aims to protect workers from the health effects of H2S, including respiratory issues and potential neurological damage, since H2S is a toxic and potentially lethal gas encountered in various industrial sectors. Establishing a limit of 20 ppm helps ensure that workers are not exposed to hazardous levels that could lead to acute or chronic health risks.

The other options, although representing various levels of exposure, do not correspond to OSHA's established PEL for H2S. The focus on 20 ppm is crucial for maintaining safety standards in environments where this gas might be present.