Approval of Post-1996 Rate of Progress Plan: Indiana

In this action, EPA is approving the Lake and Porter Counties, Indiana Post-1996 Rate of Progress (ROP) Plan, including a 1990 inventory adjustment, as revisions to the State Implementation Plan (SIP). The Indiana Department of Environmental Management (IDEM) submitted the Post-1996 ROP Plan on December 17, 1997, with a supplemental submission on January 22, 1998. The control strategies in the plan are designed to reduce volatile organic compounds (VOC) emissions in Lake and Porter Counties by 9 percent (%) from 1990 baseline levels. The Clean Air Act (the Act) requires that these reductions occur by November 15, 1999. The Post- 1996 ROP Plan is designed to reduce VOC emissions in Lake and Porter Counties by at least 77,366 pounds (lbs) per day; from a projected 369,387 lbs/day to 292,021 pounds/day. VOC emissions combine with oxides of nitrogen in the atmosphere to form ground-level ozone, a pollutant which can cause inflammation of the lungs, decrease lung capacity, and aggravate asthma. The purpose of this Federal Register action is to explain what EPA is approving and to discuss the rationale for today's approval.