IN 2000 AND 2003, O-N MODIFIED ITS ROTARY KILN WITHOUT FILING ANY PERMIT APPLICATIONS WITH VA-DEQ. A 2007 STACK TEST SHOWED THAT SO2 EMISSIONS INCREASED DRAMATICALLY FOLLOWING THE MODIFICATIONS, RESULTING IN AN INCREASE IN SO2, WHICH TRIGGERS PSD, AND AN INCREASE IN MAXIMUM HOURLY EMISSION RATE OF SO2, WHICH TRIGGERED THE NSPS FOR LIME KILNS (40 CFR PART 60, SUBPART HH). FOLLOWING SALE OF FACILITY, NEW OWNER CHARGED OPERATING PARAMETER FOR ROTARY KILN AND RE-STACK TESTED IN 2008, WHICH SHOWED SO2 EMISSIONS AT PRE-2000 (PRE-MODIFICATIION) LEVELS. O-N HAS SIGNED ADMIN. COMPLIANCE ORDER REQUIRING IT INSTALL SO2 CEMS AND MEET SO2 EMISSION RATE IN BART PERMIT TO BE ISSUED BY VADEQ.