(a) Applicability. An internal combustion engine, self-propelled vehicle, mechanized equipment containing an internal combustion engine, or a battery powered vehicle or equipment is subject to the requirements of this subchapter when transported as cargo on a transport vehicle, vessel, or aircraft if—

(1) The engine or fuel tank contains a liquid or gaseous fuel. An engine may be considered as not containing fuel when the fuel tank, engine components, and fuel lines have been completely drained, sufficiently cleaned of residue, and purged of vapors to remove any potential hazard and the engine when held in any orientation will not release any liquid fuel;

(2) It is equipped with a wet electric storage battery other than a non-spillable battery; or

(3) Except as provided in paragraph (d)(1) of this section, it contains other hazardous materials subject to the requirements of this subchapter.

(b) Requirements. Unless otherwise excepted in paragraph (b)(4) of this section, vehicles, engines and equipment are subject to the following requirements:

(1) Flammable liquid fuel. A fuel tank containing a flammable liquid fuel must be drained and securely closed, except that up to 500 mL (17 ounces) of residual fuel may remain in the tank, engine components, or fuel lines provided they are securely closed to prevent leakage of fuel during transportation. Self-propelled vehicles containing diesel fuel are excepted from the requirement to drain the fuel tanks, provided that sufficient ullage space has been left inside the tank to allow fuel expansion without leakage, and the tank caps are securely closed.

(2) Flammable liquefied or compressed gas fuel. Fuel tanks and fuel systems containing flammable liquefied or compressed gas fuel must be securely closed. For transportation by water, the requirements of §§ 176.78(k) and 176.905 of this subchapter apply. For transportation by air, the fuel tank and fuel system must be emptied and securely closed or must be removed, packaged and transported in accordance the requirements of this subchapter.

(3) Truck bodies or trailers on flat cars—flammable liquid or gas powered. Truck bodies or trailers with automatic heating or refrigerating equipment of the flammable liquid type may be shipped with fuel tanks filled and equipment operating or inoperative, when used for the transportation of other freight and loaded on flat cars as part of a joint rail and highway movement, provided the equipment and fuel supply conform to the requirements of § 177.834(l) of this subchapter.

(4) Modal exceptions. Quantities of flammable liquid fuel greater than 500 mL (17 ounces) may remain in self-propelled vehicles and mechanical equipment only under the following conditions:

(i) For transportation by motor vehicle or rail car, the fuel tanks must be securely closed.

(ii) For transportation by vessel, the shipment must conform to § 176.905 of this subchapter.

(iii) For transportation by aircraft designed or modified for vehicle ferry operations, the shipment must conform to § 175.305 of this subchapter.

(c) Wet battery powered or installed. Wet batteries must be securely installed and fastened in an upright position. Batteries must be protected against short circuits and leakage or removed and packaged separately under § 173.159. Battery powered vehicles, machinery or equipment including battery powered wheelchairs and mobility aids are excepted from the requirements of this subchapter when transported by rail, highway or vessel.

(d) Other hazardous materials. (1) Items of equipment containing hazardous materials, fire extinguishers, compressed gas accumulators, safety devices and other hazardous materials which are integral components of the motor vehicle, engine or mechanical equipment and are necessary for the operation of the vehicle, engine or equipment, or for the safety of its operator or passengers must be securely installed in the motor vehicle, engine or mechanical equipment. Such items are not otherwise subject to the requirements of this subchapter.

(2) Other hazardous materials must be packaged and transported in accordance with the requirements of this subchapter.

(e) Exceptions. Except as provided in paragraph (d)(2) of this section, shipments made under the provisions of this section—

(1) Are not subject to any other requirements of this subchapter, for transportation by motor vehicle or rail car; and

(2) Are not subject to the requirements of subparts D, E and F (marking, labeling and placarding, respectively) of part 172 of this subchapter or § 172.604 of this subchapter (emergency response telephone number) for transportation by vessel or aircraft. For transportation by aircraft, all other applicable requirements of this subchapter, including shipping papers, emergency response information, notification of pilot-in-command, general packaging requirements, and the requirements specified in § 173.27 must be met. For transportation by vessel, additional exceptions are specified in § 176.905 of this subchapter.