...
(a) Applicability. The rules in this section apply to compressed natural gas (CNG) fuel containers used for supplying fuel for the operation of commercial motor vehicles or for the operation of auxiliary equipment installed on, or used in connection with commercial motor vehicles.
(b) CNG containers manufactured on or after March 26, 1995. Any motor vehicle manufactured on or after March 26, 1995, and equipped with a CNG fuel tank must meet the CNG container requirements of FMVSS No. 304 (49 CFR 571.304) in effect at the time of manufacture of the vehicle.
(c) Labeling. Each CNG fuel container shall be permanently labeled in accordance with the requirements of FMVSS No. 304, S7.4.
[70 FR 48053, Aug. 15, 2005]