Xtreme Heaters Engine Compartment Heaters are designed to meet rigid Coast Guard and ABYC safety standards and have been tested for MIL-SPEC vibration, humidity and temperature performance compliance. Xtreme heaters are designed to safely operate in engine compartments and bilge areas which may contain explosive fuel vapors. Don't rely on unsafe alternatives like space heaters or trouble lights - Get an Xtreme Heater and get peace of mind.