Approval and Promulgation of Air Quality Implementation Plans; Illinois

EPA is approving a revision to the Illinois Ozone State Implementation Plan (SIP). On August 17, 2005, Illinois requested that five compounds be added to its list of compounds that are exempt from being considered as volatile organic compounds (VOCs). EPA no longer considers four of the compounds to be VOCs for control and recordkeeping/reporting purposes because the compounds were shown to be negligibly photochemically reactive, and do not lead to ozone formation. EPA, however, determined that tertiary-butyl acetate (t- butyl acetate) has negligible contribution to ozone formation, and, therefore, is not considered a VOC for emission limits and VOC control requirements, it should, noneless, continue to be covered by recordkeeping, emission reporting, and inventory requirements. Illinois provided a supplementary submission on January 29, 2008, correcting the August 17, 2007, submittal by clarifying the restrictions pertaining to the compound t-butyl acetate.