When do investigators typically return to their duties during a Toxic Gas casualty?

Investigators typically return to their duties during a Toxic Gas casualty when they are relieved by the fire party or repair party. This is crucial because, during a toxic gas incident, the initial responders, including investigators, must prioritize their safety and the safety of others. The fire party or repair party, upon being trained and equipped, will take over the responsibilities, allowing investigators to step back from an environment that may still pose an imminent risk.

This process ensures a smooth transition of responsibility and reinforces the importance of having personnel specifically trained for hazardous situations managing the scene. Investigators cannot assess the air quality or the safety of the situation effectively while they are still engaged in active response roles, and thus they must wait for the appropriate relief to take over before resuming any investigative duties.