All vessels are required to have a Type B, USCG–approved fire extinguisher on board if one or more of the following conditions exist:
- Inboard/outboard or inboard engine
- Closed compartments
- Closed living spaces
- Closed storage compartments in which flammable or explosive gases or vapors may become entrapped
- Permanently installed fuel tanks
Approved types of fire extinguishers are identified by the following marking on the label—“Marine Type USCG Approved”—followed by the type and size symbols and the approval number.