Mr. J. Brian Powers
NGV Sales and Service Manager
BC Gas Utility Ltd.
207-4190 Lougheed Highway
Burnaby, British Columbia
Canada V5C 6A8

Dear Mr. Powers:

This responds to your letter asking whether Compressed Natural Gas (CNG) containers used as fuel tanks for motor vehicles in the United States require periodic hydrostatic testing. You stated that these containers had been purchased by BC gas and stored in a warehouse, but did not state the date of their manufacture. The answer is no. This agency, the National Highway Traffic Safety Administration (NHTSA), has no authority to require the periodic testing of motor vehicles or items of motor vehicle equipment, after the first consumer purchase.

Congress has authorized NHTSA to issue Federal motor vehicle safety standards (FMVSSs) for new motor vehicles and new items of motor vehicle equipment. The agency has exercised this authority to issue FMVSS No. 304, Compressed natural gas fuel container integrity, (49 CFR 571.304) which specifies requirements for the integrity of new CNG containers used to fuel motor vehicles. One such requirement is that each new CNG container comply with a hydrostatic burst test. Each new CNG container manufactured on or after March 27, 1995 (the date the standard took effect) must comply with the hydrostatic burst test and the other requirements in FMVSS No. 304 and be certified as complying with that standard when it is sold. However, after the first consumer purchase of a motor vehicle or an item of motor vehicle equipment, NHTSA's authority is much more limited and does not extend to periodic hydrostatic testing (or any other periodic testing) of motor vehicles or such equipment.

I wish to note that another agency of the U.S. Department of Transportation, the Research and Special Programs Administration (RSPA), is authorized by Congress to issue standards for containers used to transport hazardous materials, including CNG containers. RSPA, however, does not have the statutory authority to regulate CNG containers that are used to fuel a motor vehicle. In other words, there are no Federal requirements applicable to the periodic retesting of CNG containers designed to fuel a motor vehicle.

Even though there are no Federal requirements about the periodic hydrostatic testing of CNG containers used to fuel motor vehicles, each state has the authority to regulate motor vehicles while they are in use. Accordingly, a state could regulate the testing of CNG containers in the aftermarket.

I hope you find this information helpful. If you have any other questions, please contact Marvin Shaw at this address or by phone at (202) 366-2992.


Samuel J. Dubbin Chief Counsel

ref: 304 d:4/19/96