(a) Approval - On January 12, 1993, the Connecticut Department of Environmental Protection submitted a revision to the carbon monoxide State Implementation Plan for the 1990 base year emission inventory. The inventory was submitted by the State of Connecticut to satisfy Federal requirements under sections 172(c)(3) and 187(a)(1) of the Clean Air Act as amended in 1990, as a revision to the carbon monoxide State Implementation Plan for the Hartford/New Britain/Middletown carbon monoxide nonattainment area, the New Haven/Meriden/Waterbury carbon monoxide nonattainment area, and the Connecticut Portion of the New York-N. New Jersey-Long Island carbon monoxide nonattainment area.

(b) Approval - On September 30, 1994, the Connecticut Department of Environmental Protection submitted a request to redesignate the Hartford/New Britain/Middletown Area carbon monoxide nonattainment area to attainment for carbon monoxide. The redesignation request and the 1995-2005 initial ten-year maintenance plan meet the redesignation requirements in sections 107(d)(3)(E) and 175A of the Act as amended in 1990, respectively.

(c) Approval - On January 12, 1993 and April 7, 1994, the Connecticut Department of Environmental Protection submitted revisions to the carbon monoxide State Implementation Plan for VMT forecasts, contingency measures, and attainment demonstration for CO. These VMT forecasts, contingency measures, and attainment demonstration were submitted by Connecticut to satisfy Federal requirements under sections 187(a)(2)(A), 187(a)(3) and 187(a)(7) of the Clean Air Act, as amended in 1990, as revisions to the carbon monoxide State Implementation Plan.

(d) Approval - On January 17, 1997, the Connecticut Department of Environmental Protection submitted a request to redesignate the New Haven/Meriden/Waterbury carbon monoxide nonattainment area to attainment for carbon monoxide. The redesignation request and the 1998-2008 initial ten-year maintenance plan meet the redesignation requirements in sections 107(d)(3)(E) and 175A of the Act as amended in 1990, respectively.

(e) Approval - In December, 1996, the Connecticut Department of Environmental Protection submitted a revision to the carbon monoxide State Implementation Plan for the 1993 periodic emission inventory. The inventory was submitted by the State of Connecticut to satisfy Federal requirements under section 187(a)(5) of the Clean Air Act as amended in 1990, as a revision to the carbon monoxide State Implementation Plan.

(f) Approval - On May 29, 1998, the Connecticut Department of Environmental Protection submitted a request to redesignate the Connecticut portion of the New York-N. New Jersey-Long Island carbon monoxide nonattainment area to attainment for carbon monoxide. The redesignation request and the 2000-2010 initial ten-year maintenance plan meet the redesignation requirements in sections 107(d)(3)(E) and 175A of the Act as amended in 1990, respectively.

(g) Approval - On October 7, 1999, the Connecticut Department of Environmental Protection submitted a revision to the carbon monoxide State Implementation Plan that removes the oxygenated fuel requirement for the Connecticut portion of the New York - N. New Jersey - Long Island area and converts the program to a contingency measure. If a violation of the carbon monoxide ambient air quality standard were to occur, the State would be required to reimplement the program.

(h) Approval - On June 28, 2004, the Connecticut Department of Environmental Protection (CT DEP) submitted a request to establish limited maintenance plans for the Hartford-New Britain-Middletown Connecticut carbon monoxide attainment area, the New Haven-Meriden-Waterbury Connecticut carbon monoxide attainment area, and the Connecticut portion of the New York-Northern New Jersey-Long Island carbon monoxide attainment area for the remainder of the individual area's initial ten-year maintenance plan. As part of the maintenance plan request, CT DEP also requested approval of a second follow-on ten-year carbon monoxide maintenance plan for the Hartford-New Britain-Middletown carbon monoxide attainment area (period 2006 to 2015), for the New Haven-Meriden-Waterbury carbon monoxide attainment area (period 2009 to 2018), and for the Connecticut portion of the New York-Northern New Jersey-Long Island carbon monoxide attainment area (period 2011 to 2020). The State of Connecticut has committed to: maintain a continuous carbon monoxide monitoring network in each carbon monoxide maintenance area; implement contingency measures in the event of an exceedance of the carbon monoxide National Ambient Air Quality Standard (NAAQS) in any of the three maintenance areas; coordinate with EPA in the event the carbon monoxide design value(s) in any maintenance area(s) exceed 7.65 ppm, to verify the validity of the data and, if warranted based on the data review, develop a full maintenance plan(s) for the affected maintenance area(s); and, ensure that project-level carbon monoxide evaluations of transportation projects in each area are carried out as part of environmental reviews or Connecticut's indirect source permitting program. The limited maintenance plans satisfy all applicable requirements of section 175A of the Clean Air Act. Approval of a Limited Maintenance Plan is conditioned on maintaining levels of ambient carbon monoxide levels below the required limited maintenance plan 8-hour carbon monoxide design value criterion of 7.65 parts per million. If the Limited Maintenance Plan criterion is no longer satisfied, Connecticut must develop a full maintenance plan to meet Clean Air Act requirements.