104 STAT. 2524 PUBLIC LAW 101-549—NOV. 15, 1990 applicable regulations implementing such provisions as the Administrator deems necessary to implement this part. "(c) ENFORCEMENT.—Any person who converts conventional vehicles to clean fuel vehicles pursuant to subsection (b), shall be considered a manufacturer for purposes of sections 206 and 207 and related enforcement provisions. Nothing in the preceding sentence shall require a person who performs such conversions to warrant any part or operation of a vehicle other than as required under this part. Nothing in this paragraph shall limit the applicability of any other warranty to unrelated parts or operations. "(d) TAMPERING. —The conversion from a vehicle capable of operating on gasoline or diesel fuel only to a clean-fuel vehicle shall not be considered a violation of section 203(a)(3) if such conversion complies with the regulations promulgated under subsection (b). "(e) SAFETY.—The Secretary of Transportation shall, if necessary, promulgate rules under applicable motor vehicle laws regarding the safety of vehicles converted from existing and new vehicles to cleanfuel vehicles. 42 USC 7588. " SEC. 248. FEDERAL AGENCY FLEETS. "(a) ADDITIONAL PROVISIONS APPLICABLE.—The provisions of this section shall apply, in addition to the other provisions of this part, in the case of covered fleet vehicles owned or operated by an agency, department, or instrumentality of the United States, except as otherwise provided in subsection (e). " (b) COST OF VEHICLES TO FEDERAL AGENCY.—Notwithstanding the provisions of section 211 of the Federal Property and Administrative Services Act of 1949, the Administrator of General Services shall not include the incremental costs of clean-fuel vehicles in the amount to be reimbursed by Federal agencies if the Administrator of General Services determines that appropriations provided pursuant to this paragraph are sufficient to provide for the incremental cost of such vehicles over the cost of comparable conventional vehicles. "(c) LIMITATIONS ON APPROPRIATIONS.—Funds appropriated pursuant to the authorization under this paragraph shall be applicable only— "(1) to the portion of the cost of acquisition, maintenance and operation of vehicles acquired under this subparagraph which exceeds the cost of acquisition, maintenance and operation of comparable conventional vehicles; "(2) to the portion of the costs of fuel storage and dispensing equipment attributable to such vehicles which exceeds the costs for such purposes required for conventional vehicles; and "(3) to the portion of the costs of acquisition of clean-fuel vehicles which represents a reduction in revenue from the disposal of such vehicles as compared to revenue resulting from the disposal of comparable conventional vehicles. "(d) VEHICLE COSTS. —The incremental cost of vehicles acquired under this part over the cost of comparable conventional vehicles shall not be applied to any calculation with respect to a limitation under law on the maximum cost of individual vehicles which may be required by the United States. "(e) EXEMPTIONS.—The requirements of this part shall not apply to vehicles with respect to which the Secretary of Defense has certified to the Administrator that an exemption is needed based on national security consideration.