Section 257.681 - Bus; fire extinguisher required(1) A person, owner, or motor carrier shall not drive a bus or cause or permit a bus to be driven or moved, unless the bus is equipped with properly filled fire extinguishers as follows: (a) If the bus is used to transport hazardous materials and required to be marked or placarded pursuant to 49 C.F.R. parts 100 to 199, a fire extinguisher having an underwriters laboratories rating of 10 B:C or more.(b) If the bus is not used to transport hazardous materials, either a fire extinguisher having an underwriters laboratories rating of 5 B:C or more, or 2 fire extinguishers having an underwriters laboratories rating of 4 B:C or more.(2) The fire extinguishers required by this section shall be securely mounted on the vehicle in a location readily accessible for use. The fire extinguishers shall be designed, constructed, and maintained to permit a determination of whether they are fully charged and in proper operating condition.(3) A fire extinguisher, required under this section, must have an extinguishing agent that does not need protection from freezing.(4) A fire extinguisher, required under this section, must not use a vaporizing liquid that gives off vapors more toxic than those shown as having toxicity rating of 5 or 6 in the underwriters' laboratories classification of comparative life hazard of gases and vapors.(5) Each fire extinguisher required under this section must be labeled or marked with its underwriters' laboratories rating.Add. 1988, Act 219, Imd. Eff. 7/1/1988 .