Which statement is NOT true of a supplied-air respirator?

The statement indicating that a supplied-air respirator provides a virtually unrestricted supply of air is not true. While supplied-air respirators are designed to deliver breathing air from a clean, filtered source, they are not completely unrestricted. These systems often have limitations, such as the length of the hose, the air pressure from the supply, and potential blockages or obstructions that can affect airflow.

In emergency situations or hazardous environments, the supply of air must be managed carefully to ensure the safety of the user. The other statements accurately reflect relevant characteristics and considerations when using supplied-air respirators, such as the hazards related to the air supply hose, the need to avoid using pure oxygen, and the frequent usage of these respirators during emergency responses.