Which level of protection is NOT designed for oxygen-deficient areas?

Level C protection is designed for situations where the atmospheric concentration of substances is known, and the presence of harmful substances can be monitored. This level typically includes chemical-resistant clothing and is appropriate for environments that contain oxygen at sufficient levels. In contrast, Level C is not suitable for oxygen-deficient areas because it does not include a self-contained breathing apparatus (SCBA).

In environments lacking sufficient oxygen, the use of SCBA is essential to ensure the safety of responders since respirators used in Level C do not provide independent oxygen supply. Level A, with a fully encapsulated suit and SCBA, is specifically intended for highly hazardous materials and situations where both chemical exposure and oxygen deficiency are concerns. Similarly, Level B is also equipped with SCBA, making it suitable for similar hazardous conditions. Level D is the lowest level of protection and is generally used for work activities with minimal risk and sufficient oxygen. Thus, the correct answer highlights the limitation of Level C in oxygen-deficient scenarios.