Which type of supplied air respirators is prohibited for use?

Demand only respirators are indeed prohibited for use in certain hazardous environments. These types of respirators only provide air when the wearer inhales, which means they rely on the user's respiratory effort. In situations where there is a risk of exposure to harmful airborne contaminants or a sudden release of hazardous substances, this design can be insufficient because the respirator may not deliver adequate air supply during moments of high breathing demand, such as heavy physical exertion.

The continuous flow respirators, powered air-purifying respirators, and self-contained breathing apparatus are designed to provide a continuous supply of clean air, making them much safer for use in environments where airborne hazards are present. This continuous airflow helps ensure that the user receives an adequate supply of breathable air, regardless of their breathing pattern or activity level.