Approval and Promulgation of Air Quality Implementation Plans; Illinois; Revisions to Emission Reduction Market System

In 1997, Illinois adopted and submitted rules establishing a cap and trade program regulating emissions of volatile organic compounds (VOC). The program, known as the Emission Reduction Market System (ERMS), was designed to address VOC sources in the Chicago area with potential to emit at least 25 tons per year. Then, in 2004, the Chicago ozone nonattainment area was in effect reclassified from severe to moderate, which according to EPA guidance revised the applicable definition of major sources from 25 tons per year to 100 tons per year. This "reclassification" could have resulted in the program no longer including sources with potential to emit more than 25 but less than 100 tons per year. Instead, Illinois adopted rule revisions, submitted to EPA on January 10, 2007, which required that these sources remain part of the program. Illinois' rule revisions also addressed other potential ramifications of the "reclassification." EPA is approving these rule revisions.