The U.S. Environmental Protection Agency on Feb. 16 told the state of Mississippi that the area around the coal-fired, 400-MW R.D. Morrow plant of the South Mississippi Electric Power Association is in attainment for the SO2 NAAQS.
Under section 107(d) of the Clean Air Act (CAA), EPA must designate areas as either “unclassifiable,” “attainment,” or “nonattainment” for the 2010 one-hour sulfur dioxide (SO2) primary national ambient air quality standard (NAAQS). The CAA defines a nonattainment area as one that does not meet the NAAQS or that contributes to a violation in a nearby area. An attainment area is any area other than a nonattainment area that meets the NAAQS. Unclassifiable areas are defined as those that cannot be classified on the basis of available information as meeting or not meeting the NAAQS.
The state of Mississippi submitted updated recommendations to EPA in September 2015, ahead of a July 2, 2016, deadline for the EPA to designate certain areas. This deadline, established by the U.S. District Court for the Northern District of California in a lawsuit brought by environmental groups, is the first of three deadlines established by the court for the EPA to complete area designations for the 2010 SO2 NAAQS.
Lamar County, Mississippi, contains a stationary source that according to the EPA’s Air Markets Database emitted in 2012 either more than 16,000 tons of SO2 or more than 2,600 tons of SO2 and had an annual average emission rate of at least 0.45 lbs SO2/mmBTU. As of March 2, 2015, this stationary source had not met the specific requirements for being “announced for retirement,” which would exclude it from this process.
Specifically, in 2012, the R.D. Morrow Sr. Generating Plant emitted 3,948 tons of SO2, and had an emissions rate of 0.64 lbs SO2/mmBTU. Pursuant to the March 2, 2015 court-ordered schedule, the EPA must designate the area surrounding the facility by July 2, 2016.
In its submission to EPA, Mississippi recommended that the area surrounding the R.D. Morrow Plant, specifically the entirety of Lamar County, be designated as unclassifiable/attainment. “After careful review of the state’s assessment, supporting documentation, and all available data, the EPA agrees that the Lamar County Area is attaining the standard, and intends to designate Lamar County as unclassifiable/attainment,” said EPA in a Feb. 16 preliminary decision issued ahead of the July 2 deadline.
The R.D. Morrow plant, owned and operated by South Mississippi Electric Power Association, is located in central Mississippi in the eastern portion of Lamar County.