Approval and Promulgation of State Implementation Plans; Illinois

The EPA is approving a site-specific revision to the Illinois volatile organic compound (VOC) State Implementation Plan (SIP) for Argonne National Laboratory's (Argonne) degreasing operations. Argonne is a United States government-owned research and development facility in Argonne, DuPage County, Illinois. By its submittal dated March 11, 2004, the Illinois Environmental Protection Agency (Illinois EPA) requested that EPA approve an Adjusted Standard, from Illinois' cold cleaning regulations, for Argonne's solvent cleaning operations because its research activities require sample surface areas to be completely free of any residual contamination, necessitating the use of cleaning solvents that exceed the vapor pressure limitations of Illinois' cold cleaning regulations. EPA is approving this adjusted standard because there are no feasible alternatives for the preparation of sample materials and associated apparatus used for research and development at Argonne's DuPage facility and also because no more than one ton per year of solvents are used for cold cleaning. The rationale for the approval and other information are provided in this rulemaking action.