Approval and Promulgation of Air Quality Implementation Plans; District of Columbia, Maryland, Virginia; Post 1996 Rate-of-Progress Plans and One-Hour Ozone Attainment Demonstrations

EPA is conditionally approving the severe ozone nonattainment area State Implementation Plan (SIP) revision for the Metropolitan Washington severe ozone nonattainment area. This SIP revision includes the one-hour severe ozone attainment demonstration, the 1996-1999 portion of the severe area rate-of-progress (ROP) plan and transportation control measures for the Metropolitan Washington DC ozone nonattainment area (the Washington area) submitted by the District of Columbia's Department of Health (DoH), by the Maryland Department of the Environment (MDE) and by the Virginia Department of Environmental Quality (VADEQ). EPA is conditioning approval on commitments submitted by DoH, MDE and VADEQ to submit adopted control measures that qualify as contingency measures to be implemented for failure of the Washington area to attain the one-hour ozone standard for serious areas by November 15, 1999 and adopted contingency measures that will be implemented should the area fail to attain by the November 15, 2005 severe ozone attainment deadline or fail to achieve any post- 1996 three-percent year emissions reduction requirement. Approval is also conditioned on commitments that require the Washington area jurisdictions to submit a revised rate-of-progress plan that includes emission reductions of ozone precursors of at least 3 percent per year from November 15, 1999 to the November 15, 2005, an updated attainment demonstration that reflects revised MOBILE6-based motor vehicle emissions budgets, a revised analysis of reasonably available control measures (RACM) and to revise the attainment demonstration as necessary to reflect the revised budgets and RACM analysis. Approval is also conditioned on the Washington area jurisdictions submitting a SIP revision that meets all of the requirements of a severe area SIP including, but not limited to lower major stationary source thresholds, revised offset ratios, any required transportation control strategies and a fee requirement for majo