On February 17, EPA publicly released its anticipated second round of proposed area designations under the 1-Hour SO2 standard.  The proposed designations and technical support documents underlying the recommendations are available here.

The proposed designations respond to recommendations from the states and address 66 areas located in 24 states.   Whereas in total the states together recommended only three areas to be designated nonattainment, EPA has recommended a nonattainment designation for 12 areas.  Those areas are located in Illinois (2), Indiana (2), Louisiana (1), Maryland (1), Michigan (1), Missouri (1), Oklahoma (1), and Texas (3).   EPA recommends “unclassifiable / attainment” or “unclassifiable” designations for the remaining 54 areas.  EPA plans to publish its recommendations in the Federal Register and allow 30 days for public review and comment. The area designations are scheduled to be finalized by July 2016.

While the Clean Air Act requires EPA to make final designations within three years of its issuance of a new ambient air quality standard, EPA has established a much longer designation process under the 1-Hour SO2 standard.  The standard was issued in 2010, and in a controversial move, EPA is designating areas in stages over a 10-year period.  EPA issued the first round of area designations in 2013 and designated only those areas with monitored nonattainment of the standard—29 areas in 16 states.  Rather than designating the remaining areas of the country attainment or unclassifiable, as it has under other standards, EPA claimed that it had insufficient information to make any additional designations at that time and indicated that it would undertake a rulemaking to gather the data needed to complete the designation process.

Environmental groups and several states sued EPA for failing meet its statutory obligation to designate all areas. EPA ultimately entered into a consent decree with the environmental groups, setting a schedule for designating areas in three additional phases—July 2016, December 2017 and December 2020.  That consent decree has been appealed by the states.

At the same time that it entered the consent decree, EPA was in the midst of its rulemaking to establish the process and schedule for the remaining area designations. The rule, known as the Data Requirements Rule, defines the data required for purposes of making final area designations under the standard.  In another break with the past, under the 1-Hour SO2 rule, rather than simply relying on ambient monitoring data collected by the states, EPA is authorizing broad use of air quality modeling for area designations. Many of EPA’s nonattainment recommendations released this week are based on air quality modeling as opposed to monitored violations, including modeling submitted by the Sierra Club in some cases.

If you have questions about EPA’s recommended area designations, please contact Margaret Campbell or Mack McGuffey.