EPA Extends SO2 Designations Timeline

The EPA is extending the deadline for area designations for the 2010 primary SO2 standard until June 3, 2013 due to insufficient information.

The Clean Air Act requires the EPA to complete the designation process within two years of the promulgation date of a revised standard unless there is insufficient information to make these decisions.

On June 3, 2010, the EPA revised the health-based standard for SO2 by setting a new 1-hour standard of 75 parts per billion (ppb). In March 2011, the EPA issued guidance on designations for the 2010 primary SO2 standard. This guidance included recommendations on how to conduct modeling for designations. In addition, in October 2011, the EPA published draft guidance on state implementation plan submissions for the 2010 primary SO2 standard and invited public comment on the draft guidance from October 3, 2011, to December 2, 2011.

In light of the comments received on the September 2011 Guidance, including those regarding the timing and approach for issuing initial area designations, and the subsequent comments received as part of the stakeholder outreach process in May and June 2012, the EPA acknowledges that it remains significantly uncertain what analytic approach sources, states, and the EPA will consistently and cooperatively use to make the determinations required under the CAA with respect to both current and future air quality. Because the issues involved, and the comments received on the draft guidance, relate to determinations of both the boundaries of areas currently meeting or not meeting the NAAQS and whether such areas will or will not meet the NAAQS in the future, the EPA agrees that it should make effective use of the additional time allowed under the CAA to promulgate designations. The EPA has insufficient data at this time to promulgate designations, including where it is necessary to identify nearby contributing areas and to determine boundaries of possible nonattainment areas, which the EPA cannot expect to definitively determine with full cooperation of stakeholders in advance of resolving outstanding issues and uncertainty regarding the most appropriate implementation approach, including determining whether an area meets or does not meet the new NAAQS. Therefore, the EPA concludes that it currently has insufficient information to promulgate designations by June 2012, and intends under these circumstances to take additional time, up to 1 additional year, allowed under the CAA for promulgating initial designations for the 2010 primary SO2 NAAQS.

By taking the additional time, the EPA is now required under CAA section 107 to promulgate designations by June 3, 2013. The EPA expects to take additional time, as necessary, to appropriately assess designations. For some areas, EPA anticipates it will not be necessary to take the full additional year, and in those cases EPA will proceed sooner than June 2013. For example, the EPA intends to make its best effort to promulgate final designations for areas with monitored violations of the SO2 NAAQS by the end of calendar year 2012, subject to being able to resolve issues related to nonattainment boundary determinations and contributions from nearby areas, rather than take until June 2013 for those areas.

Additional information on the SO2 standards, including information on Wisconsin’s implementation process, is available on this Regulatory Watch website.

This post was authored by GLLF staff attorney Emily Kelchen.