Infrastructure SIP Requirements for the 2006 PM Standard

The EPA is proposing to approve some elements, and disapprove other elements, of State Implementation Plan (SIP) submissions by Illinois, Indiana, Michigan, Minnesota, Ohio, and Wisconsin regarding the infrastructure requirements of sections 110(a)(1) and (2) of the Clean Air Act (CAA) for the 2006 24-hour fine particle national ambient air quality standards (2006 PM2.5 NAAQS). The EPA is proposing to approval all but two revisions submitted by Wisconsin.

Wisconsin submitted revisions to its PSD program on May 12, 2011, intended to meet the requirements of the 2008 NSR Rule. Specifically, WDNR’s revisions to NR 405.02(27)(a)(5) include the significant emissions rates for direct PM2.5, and SO2 and NOX as PM2.5 precursors, consistent with the 2008 NSR Rule. However, Wisconsin’s PSD regulations include only generic language to define what constitutes a regulated NSR pollutant that does not directly account for PM2.5 and its precursors in NSR permitting. NR 405(02)(25i) defines ‘‘Regulated NSR air contaminant’’ as ‘‘[a]ny air contaminant for which a national ambient air quality standard has been promulgated and any constituents or precursors for the air contaminants identified by the administrator * * *.’’

The 2008 NSR Rule obligates the State to explicitly identify the precursors to PM2.5 to be addressed in NSR permitting as part of the definition for ‘‘Regulated NSR air contaminant.’’ EPA notes that although Wisconsin has incorporated the significant emissions rates in accordance with the 2008 NSR Rule, WDNR has not explicitly identified SO2 and NOX as precursors to PM2.5 in defining pollutants regulated by the PSD program. Therefore, we are proposing to disapprove this narrow portion of Wisconsin’s infrastructure SIP submission for the 2006 PM2.5 NAAQS with respect to the requirements of section 110(a)(2)(C) regarding the identification of PM2.5 precursors.

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Wisconsin submitted revisions to its PSD program on May 12, 2011. However, these revisions do not incorporate the necessary changes regarding the regulation of condensables for PM2.5 and PM10, nor does Wisconsin’s existing SIP account for PM2.5 and PM10 condensables.

Therefore, EPA is proposing to disapprove this narrow portion of Wisconsin’s infrastructure SIP submission for the 2006 PM2.5 NAAQS with respect to the requirements of section 110(a)(2)(C) regarding the regulation of PM2.5 and PM10 condensables in the PSD program.

In the proposed rulemaking the EPA pledges to work with the DNR to remedy Wisconsin’s deficiencies, and therefore will not be imposing a FIP.

EPA will actively work with Wisconsin to incorporate changes to its PSD program that explicitly identify PM2.5 precursors and account for PM2.5 and PM10 condensables in permitting emissions limits, consistent with the 2008 NSR Rule. In the interim, EPA expects WDNR to adhere to the associated requirements of the 2008 NSR Rule in its PSD program, specifically with respect to the explicit identification of PM2.5 precursors, and the accounting for PM2.5 and PM10 condensables in permitting emissions limits.

The rulemaking notes, “Although not specific to this action, EPA will also continue to work with WDNR to ensure that revisions to the State’s PSD program contain provisions that explicitly identify NOX as a precursor to ozone, consistent with the Phase 2 Rule.”

Comments on the EPA’s proposed rulemaking approving the changes to Wisconsin’s SIP must be received on or before September 4, 2012.

This post was authored by GLLF staff attorney Emily Kelchen.