(a) Moderate Areas
Each State in which all or part of a Moderate Area is located shall, with respect to the Moderate Area (or portion thereof, to the extent specified in guidance of the Administrator issued before November 15, 1990), submit to the Administrator the State implementation plan revisions (including the plan items) described under this subsection, within such periods as are prescribed under this subsection, except to the extent the State has made such submissions as of November 15, 1990:

(1) Inventory
No later than 2 years from November 15, 1990, the State shall submit a comprehensive, accurate, current inventory of actual emissions from all sources, as described in section 7502(c)(3) of this title, in accordance with guidance provided by the Administrator.

(2)(A) Vehicle miles traveled
No later than 2 years after November 15, 1990, for areas with a design value above 12.7 ppm at the time of classification, the plan revision shall contain a forecast of vehicle miles traveled in the nonattainment area concerned for each year before the year in which the plan projects the national ambient air quality standard for carbon monoxide to be attained in the area. The forecast shall be based on guidance which shall be published by the Administrator, in consultation with the Secretary of Transportation, within 6 months after November 15, 1990. The plan revision shall provide for annual updates of the forecasts to be submitted to the Administrator together with annual reports regarding the extent to which such forecasts proved to be accurate. Such annual reports shall contain estimates of actual vehicle miles traveled in each year for which a forecast was required.

(B) Special rule for Denver
Within 2 years after November 15, 1990, in the case of Denver, the State shall submit a revision that includes the transportation control measures as required in section 7511a(d)(1)(A) of this title except that such revision shall be for the purpose of reducing CO emissions rather than volatile organic compound emissions. If the State fails to include any such measure, the implementation plan shall contain an explanation of why such measure was not adopted and what emissions reduction measure was adopted to provide a comparable reduction in emissions, or reasons why such reduction is not necessary to attain the national primary ambient air quality standard for carbon monoxide.

(3) Contingency provisions
No later than 2 years after November 15, 1990, for areas with a design value above 12.7 ppm at the time of classification, the plan revision shall provide for the implementation of specific measures to be undertaken if any estimate of vehicle miles traveled in the area which is submitted in an annual report under paragraph (2) exceeds the number predicted in the most recent prior forecast or if the area fails to attain the national primary ambient air quality standard for carbon monoxide by the primary standard attainment date. Such measures shall be included in the plan revision as contingency measures to take effect without further action by the State or the Administrator if the prior forecast has been exceeded by an updated forecast or if the national standard is not attained by such deadline.

(4) Savings clause for vehicle inspection and maintenance provisions of the State implementation plan
Immediately after November 15, 1990, for any Moderate Area (or, within the Administrator's discretion, portion thereof), the plan for which is of the type described in section 7511a(a)(2)(B) of this title any provisions necessary to ensure that the applicable implementation plan includes the vehicle inspection and maintenance program described in section 7511a(a)(2)(B) of this title.

(5) Periodic inventory
No later than September 30, 1995, and no later than the end of each 3 year period thereafter, until the area is redesignated to attainment, a revised inventory meeting the requirements of subsection (a)(1).

(6) Enhanced vehicle inspection and maintenance
No later than 2 years after November 15, 1990, in the case of Moderate Areas with a design value greater than 12.7 ppm at the time of classification, a revision that includes provisions for an enhanced vehicle inspection and maintenance program as required in section 7511a(c)(3) of this title (concerning serious ozone nonattainment areas), except that such program shall be for the purpose of reducing carbon monoxide rather than hydrocarbon emissions.

(7) Attainment demonstration and specific annual emission reductions
In the case of Moderate Areas with a design value greater than 12.7 ppm at the time of classification, no later than 2 years after November 15, 1990, a revision to provide, and a demonstration that the plan as revised will provide, for attainment of the carbon monoxide NAAQS by the applicable attainment date and provisions for such specific annual emission reductions as are necessary to attain the standard by that date.

The Administrator may, in the Administrator's discretion, require States to submit a schedule for submitting any of the revisions or other items required under this subsection. In the case of Moderate Areas with a design value of 12.7 ppm or lower at the time of classification, the requirements of this subsection shall apply in lieu of any requirement that the State submit a demonstration that the applicable implementation plan provides for attainment of the carbon monoxide standard by the applicable attainment date.

(b) Serious Areas

(1) In general
Each State in which all or part of a Serious Area is located shall, with respect to the Serious Area, make the submissions (other than those required under subsection (a)(1)(B) ¹) applicable under subsection (a) to Moderate Areas with a design value of 12.7 ppm or greater at the time of classification, and shall also submit the revision and other items described under this subsection.

(2) Vehicle miles traveled
Within 2 years after November 15, 1990, the State shall submit a revision that includes the transportation control measures as required in section 7511a(d)(1) of this title except that such revision shall be for the purpose of reducing CO emissions rather than volatile organic compound emissions. In the case of any such area (other than an area in New York State) which is a covered area (as defined in section 7586(a)(2)(B) of this title) for purposes of the Clean Fuel Fleet program under part C of subchapter II, if the State fails to include any such measure, the implementation plan shall contain an explanation of why such measure was not adopted and what emissions reduction measure was adopted to provide a comparable reduction in emissions, or reasons why such reduction is not necessary to attain the national primary ambient air quality standard for carbon monoxide.

(3) Oxygenated gasoline

(A) Within 2 years after November 15, 1990, the State shall submit a revision to require that gasoline sold, supplied, offered for sale or supply, dispensed, transported or introduced into commerce in the larger of—

(i) the Consolidated Metropolitan Statistical Area (as defined by the United States Office of Management and Budget) (CMSA) in which the area is located, or

(ii) if the area is not located in a CMSA, the Metropolitan Statistical Area (as defined by the United States Office of Management and Budget) in which the area is located,

be blended, during the portion of the year in which the area is prone to high ambient concentrations of carbon monoxide (as determined by the Administrator), with fuels containing such level of oxygen as is necessary, in combination with other measures, to provide for attainment of the carbon monoxide national ambient air quality standard by the applicable attainment date and maintenance of the national ambient air quality standard thereafter in the area. The revision shall provide that such requirement shall take effect no later than October 1, 1993, and shall include a program for implementation and enforcement of the requirement consistent with guidance to be issued by the Administrator.

(B) Notwithstanding subparagraph (A), the revision described in this paragraph shall not be required for an area if the State demonstrates to the satisfaction of the Administrator that the revision is not necessary to provide for attainment of the carbon monoxide national ambient air quality standard by the applicable attainment date and maintenance of the national ambient air quality standard thereafter in the area.

(c) Areas with significant stationary source emissions of CO

(1) Serious Areas
In the case of Serious Areas in which stationary sources contribute significantly to carbon monoxide levels (as determined under rules issued by the Administrator), the State shall submit a plan revision within 2 years after November 15, 1990, which provides that the term "major stationary source" includes (in addition to the sources described in section 7602 of this title) any stationary source which emits, or has the potential to emit, 50 tons per year or more of carbon monoxide.

(2) Waivers for certain areas
The Administrator may, on a case-by-case basis, waive any requirements that pertain to transportation controls, inspection and maintenance, or oxygenated fuels where the Administrator determines by rule that mobile sources of carbon monoxide do not contribute significantly to carbon monoxide levels in the area.

(3) Guidelines
Within 6 months after November 15, 1990, the Administrator shall issue guidelines for and rules determining whether stationary sources contribute significantly to carbon monoxide levels in an area.

(d) CO milestone

(1) Milestone demonstration
By March 31, 1996, each State in which all or part of a Serious Area is located shall submit to the Administrator a demonstration that the area has achieved a reduction in emissions of CO equivalent to the total of the specific annual emission reductions required by December 31, 1995. Such reductions shall be referred to in this subsection as the milestone.

(2) Adequacy of demonstration
A demonstration under this paragraph shall be submitted in such form and manner, and shall contain such information and analysis, as the Administrator shall require. The Administrator shall determine whether or not a State's demonstration is adequate within 90 days after the Administrator's receipt of a demonstration which contains the information and analysis required by the Administrator.

(3) Failure to meet emission reduction milestone
If a State fails to submit a demonstration under paragraph (1) within the required period, or if the Administrator notifies the State that the State has not met the milestone, the State shall, within 9 months after such a failure or notification, submit a plan revision to implement an economic incentive and transportation control program as described in section 7511a(g)(4) of this title. Such revision shall be sufficient to achieve the specific annual reductions in carbon monoxide emissions set forth in the plan by the attainment date.

(e) Multi-State CO nonattainment areas

(1) Coordination among States
Each State in which there is located a portion of a single nonattainment area for carbon monoxide which covers more than one State ("multi-State nonattainment area") shall take all reasonable steps to coordinate, substantively and procedurally, the revisions and implementation of State implementation plans applicable to the nonattainment area concerned. The Administrator may not approve any revision of a State implementation plan submitted under this part for a State in which part of a multi-State nonattainment area is located if the plan revision for that State fails to comply with the requirements of this subsection.

(2) Failure to demonstrate attainment
If any State in which there is located a portion of a multi-State nonattainment area fails to provide a demonstration of attainment of the national ambient air quality standard for carbon monoxide in that portion within the period required under this part the State may petition the Administrator to make a finding that the State would have been able to make such demonstration but for the failure of one or more other States in which other portions of the area are located to commit to the implementation of all measures required under this section (relating to plan submissions for carbon monoxide nonattainment areas). If the Administrator makes such finding, in the portion of the nonattainment area within the State submitting such petition, no sanction shall be imposed under section 7509 of this title or under any other provision of this chapter, by reason of the failure to make such demonstration.

(f) Reclassified areas
Each State containing a carbon monoxide nonattainment area reclassified under section 7512(b)(2) of this title shall meet the requirements of subsection (b) of this section, as may be applicable to the area as reclassified, according to the schedules prescribed in connection with such requirements, except that the Administrator may adjust any applicable deadlines (other than the attainment date) where such deadlines are shown to be infeasible.

(g) Failure of Serious Area to attain standard
If the Administrator determines under section 7512(b)(2) of this title that the national primary ambient air quality standard for carbon monoxide has not been attained in a Serious Area by the applicable attainment date, the State shall submit a plan revision for the area within 9 months after the date of such determination. The plan revision shall provide that a program of incentives and requirements as described in section 7511a(g)(4) of this title shall be applicable in the area, and such program, in combination with other elements of the revised plan, shall be adequate to reduce the total tonnage of emissions of carbon monoxide in the area by at least 5 percent per year in each year after approval of the plan revision and before attainment of the national primary ambient air quality standard for carbon monoxide.