On December 8, 2010, U.S. EPA proposed to approve a July 29, 2010 request by Illinois EPA (IEPA) to exempt sources in Illinois ozone nonattainment areas from additional NOx RACT requirements. These existing NOx sources are located in areas previously found to be violating the 1997 8-hour ozone standard, however, IEPA has provided data to U.S. EPA demonstrating that these areas are currently achieving that standard. As such, further emissions reductions (e.g., as would be required by the NOx RACT rules for industrial boilers codified under 35 IAC 217 Subpart E) which would take effect in 2012, are not necessary to meet the 1997 8-hour ozone air quality standard. As detailed by U.S. EPA in the January 14, 2005 policy document "Guidance on Limiting Nitrogen Oxides(NOx) Requirements Related to 8-Hour Ozone Implementation", per Section 182(f) of the Clean Air Act, certain control requirements for NOx emissions (e.g., RACT) can be waived if found to be unnecessary in achieving the ozone standard. IEPA has noted that, while the NOx RACT reductions are not necessary to comply with the current ozone standard, they would likely be relied upon as part of the future compliance efforts for the new ozone standard (which is likely to be finalized later in 2011).
Once the proposed U.S. EPA rulemaking is finalized, it is likely that IEPA would proceed with a state rulemaking effort to in some way revise (perhaps by extending the compliance date) or revoke portions of the existing NOx RACT rules. This rulemaking could present a delay in the upcoming 2012 compliance timeline for sources subject to the NOx RACT limits, but would also create an opportunity for the limits to be revised (and possibly lowered) as part of future compliance efforts for the new ozone standard which is anticipated to be significantly more stringent than the current standard. Sources currently subject to NOx RACT limits should closely follow IEPA rulemaking efforts to look for any proposals related to revising the NOx RACT rules.