What is the correct response if the cargo heater is in use while transporting hazardous materials?

The correct response when a cargo heater is in use while transporting hazardous materials is to only use it if it's drained or disconnected. This approach is vital for ensuring safety during transport. Cargo heaters can pose significant risks because, when operational, they can create conditions that may lead to overheating or can exacerbate hazardous situations, particularly with flammable or reactive materials.

By ensuring that the heater is drained or disconnected, the risk of ignition or unintentional chemical reactions is minimized. This precaution is crucial in preventing potential incidents that could lead to spills, fires, or toxic releases, which are especially critical when transporting hazardous materials. This aligns with safety protocols that emphasize caution and preventive measures in hazardous materials transportation.

The other responses imply a level of risk that is not acceptable in these situations, as keeping the heater operational or under minimal settings does not adequately address the potential dangers of heat when dealing with hazardous materials.