All vessels are required to have a Type B fire extinguisher on board if one or more of the following conditions exist:
- Closed compartments under seats where portable fuel tanks may be stored
- Closed storage compartments in which flammable or combustible materials may be stored
- Closed living spaces
- 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.