Question A tank endorsement is: Answers Only required when transporting gases. Only required when transporting liquids. Required to transport both liquids and gases. Optional when transporting hazardous materials. Explanation Subject to certain conditions, a tank endorsement is required to operate a tank vehicle that is used to haul either liquids or gases. This questions appears in the following tests: Arkansas Air Brakes District Of Columbia Class B Knowledge Test Illinois Air Brakes Indiana Air Brakes Minnesota Class A Knowledge Test Nebraska Class A Knowledge Test New Hampshire Class B Knowledge Test New Jersey Air Brakes South Dakota Double