Which gas is known for having a ceiling limit of 3 ppm and an IDLH of 50 ppm?

The chosen answer, nitrogen dioxide, is indeed recognized for its specific ceiling limit and immediately dangerous to life or health (IDLH) value. Nitrogen dioxide (NO2) is a significant air pollutant, especially in industrial environments and is formed during combustion processes. The ceiling limit is set at 3 parts per million (ppm) to protect workers from the harmful effects associated with chronic exposure to lower concentrations. An IDLH value of 50 ppm indicates that exposure to this concentration or higher poses an imminent threat to life or health, making it critical for monitoring and ensuring safety in the workplace.

The other gases listed do not align with these specific ceiling and IDLH values. Sulfur dioxide, carbon monoxide, and carbon dioxide have different established safe limits, which vary based on their toxicological profiles and effects on human health. Understanding these limits and values is vital in the mining industry where exposure to hazardous gases can occur, making it necessary for mine foremen to be familiar with these safety standards.