Fuel tanks — Is a CDL hazmat endorsement required?
Many carriers use fuel systems to power equipment mounted on a commercial motor vehicle (CMV). Do these tanks that fuel the equipment need placards? And does the driver need a hazmat endorsement on their commercial driver’s license (CDL)?
PHMSA recently clarified how the Hazardous Materials Regulations (HMR) apply to fuel systems powering equipment mounted on a motor vehicle. In this case, a company was asking about mounted fuel tanks used to operate boiler and steam units mounted on their trucks and trailers. The tanks in question were separate from the fuel tanks that powered the engine.
The bottom line? If placards are not required, no hazmat endorsement is needed to drive the vehicle.
When a tank is a fuel tank, no placards required
According to the interpretation, a fuel tank is a tank — other than a cargo tank — used to transport flammable or combustible liquid, or compressed gas, to:
- Supply fuel for propulsion of the transport vehicle to which it is attached, or
- Operate other equipment on the transport vehicle.
PHMSA noted that permanently mounted fuel tanks are not subject to the HMR with respect to their use on the vehicle, if the tanks:
- Meet the requirements of 49 CFR 393.65 and 393.67 for liquid fuel systems,
- Are used only to supply fuel to operate the motor vehicle or its auxiliary equipment, and
- Are not marked as Department of Transportation specification cargo tanks nor meet the definition of a cargo tank, as defined in 171.8.
Fuel tanks that meet these criteria are not subject to the HMR, therefore no placards are required.
When a hazmat endorsement is required
Drivers who operate any size CMV hauling hazmat in quantities that require placarding must obtain a CDL with a hazardous materials endorsement (HME). This is the same in all states and is true whether a carrier operates in intrastate or interstate commerce.
More specifically, drivers must have the HME on their CDL to drive a vehicle that transports:
- Hazardous materials that must be placarded under 49 CFR Part 172, or
- Any quantity of a select agent or toxin listed in 42 CFR Part 73.
Key to remember: If no placard is required, the CDL hazmat endorsement is not needed either.


















































