Which level of protection is needed when working in atmospheres with IDLH concentrations of a specific substance that present a severe inhalation hazard?

For situations involving atmospheres with Immediately Dangerous to Life or Health (IDLH) concentrations of a specific substance, the appropriate level of protection is crucial for ensuring the safety of the worker. Level B protection is specifically designed for environments that pose a severe inhalation hazard but may not require the highest level of skin protection.

Level B protection includes a full-face respirator and provides a higher degree of respiratory protection than Level C, which only requires a standard respirator. It allows for the use of supplied air systems that ensure that workers have a safe supply of breathable air in high-risk environments. This is particularly important in IDLH situations where the air may contain toxic vapors or gases that could lead to serious health consequences if inhaled.

In contrast, Level A protection involves a fully encapsulated suit and is typically reserved for the most hazardous environments where both respiratory and skin exposure to hazardous materials is a significant threat. Level C and D provide lower levels of protection and are not suitable for environments classified as IDLH. Level C uses lower-level respirators, and Level D does not require any respiratory protection at all, making them inappropriate choices for situations where inhalation hazards are severe.