104 STAT. 2480 PUBLIC LAW 101-549—NOV. 15, 1990 Ohio. Wisconsin. Regulations. Petroleum. model year light-duty vehicles and light-duty trucks shall contain standards which provide that emissions of carbon monoxide from such vehicles and trucks when operated at 20 degrees Fahrenheit may not exceed 3.4 grams per mile (gpm) in the case of light-duty vehicles and 4.4 grams per mile (gpm) in the case of light-duty trucks up to 6,000 GVWR and a level comparable in stringency in the case of light-duty trucks 6,000 GVWR and above. "(ii) In determining for purposes of this subparagraph whether 6 or more nonattainment areas have a carbon monoxide design value of 9.5 ppm or greater, the Administrator shall exclude the areas of Steubenville, Ohio, and Oshkosh, Wisconsin. "(3) USEFUL-LIFE FOR PHASE I AND PHASE II STANDARDS. —In the case of the standards referred to in paragraphs (1) and (2), for purposes of certification under section 206 and in-use compliance under section 207, the applicable useful life period shall be 5 years or 50,000 miles, whichever first occurs, except that the Administrator may extend such useful life period (for purposes of section 206, or section 207, or both) if he determines that it is feasible for vehicles and engines subject to such stemdards to meet such standards for a longer useful life. If the Administrator extends such useful life period, the Administrator may make an appropriate adjustment of applicable stemdards for such extended useful life. No such extended useful life shall extend beyond the useful life period provided in regulations under subsection (d). "(4) HEAVY-DUTY VEHICLES AND ENGINES. —The Administrator may also promulgate regulations under subsection (a)(1) applicable to emissions of carbon monoxide from heavy-duty vehicles and engines when operated at cold temperatures.". SEC. 205. EVAPORATIVE EMISSIONS. Section 202 of the Clean Air Act (42 U.S.C. 7521) is amended by adding the following new subsection after subsection (j): "(k) CONTROL OF EVAPORATIVE EMISSIONS.—The Administrator shall promulgate (and from time to time revise) regulations applicable to evaporative emissions of hydrocarbons from all gasolinefueled motor vehicles— "(1) during operation; and "(2) over 2 or more days of nonuse; under ozone-prone summertime conditions (as determined by regulations of the Administrator). The regulations shall take effect as expeditiously as possible and shall require the greatest degree of emission reduction achievable by means reasonably expected to be available for production during any model year to which the regulations apply, giving appropriate consideration to fuel volatility, and to cost, energy, and safety factors associated with the application of the appropriate technology. The Administrator shall commence a rulemaking under this subsection within 12 months after the date of the enactment of the Clean Air Act Amendments of 1990. If final regulations are not promulgated under this subsection within 18 months after the date of the enactment of the Clean Air Act Amendments of 1990, the Administrator shall submit a statement to the Congress containing an explanation of the reasons for the delay and a date certain for promulgation of such final regulations in accordance with this Act. Such date certain shall not be later than 15 months after the expiration of such 18 month deadline.".