SYNOPSIS OF THE CASE A. DEFENDANT'S FACILITY AND BUSINESS THE FACILITY IS ENGAGED IN THE MANUFACTURE OF PORTLAND CEMENT, SIC CODE 3241. THE FACILITY UTILIZES THE DRY PRO- CESS. TOTAL PRODUCTION CAPACITY IS APPROXIMATELY 2,850 TONS OF CLINKER PER DAY. CEMENT IS SHIPPED FROM THE FACILITY BOTH BAGGED AND IN BULK. SHIPPING IS PREDOMINANTLY BY TRUCK WITH THE BALANCE BY RAIL. THE FACILITY UTILIZES ONE LIMESTONE QUARRY AND TWO CLAY PITS. THE LIMESTONE QUARRY IS LOCATED APPROXIMATELY THREE MILES NORTHWEST OF THE FACILITY. THE PRIMARY CRUSHER IS LOCATED AT THE QUARRY WITH THE CRUSHED LIMESTONE TRUCKED TO THE FACILITY. FUGITIVE DUST AT THE LIMESTONE QUARRY AND FACILITY IS CONTROLLED BY A WATER WAGON. THE HAUL ROAD FROM THE LIMESTONE QUARRY IS OILED. ONE CLAY PIT IS LOCATED IN THE SOUTHWESTERN PORTION OF THE CITY AND CLAY IS BROUGHT FROM THIS PIT BY SELF-PROPELLED SCRAPER. THE OTHER CLAY PIT IS LOCATED SOUTHEAST OF THE CITY. CLAY IS BROUGHT FROM THIS PIT BY TRUCK. THERE IS ONE ROTARY CLAY DRYER AT THE FACILITY. THIS DRYER IS NATURAL GAS-FIRED (INTERRUPTIBLE SERVICE) WITH NO. 2 FUEL OIL STANDBY. EMISSIONS FROM THIS DRYER ARE CON- TROLLED BY A MULTICLONE AND ELECTROSTATIC PRECIPITATOR. THERE ARE NOW THREE KILNS AT THE FACILITY. THE APPROX- IMATE CLINKER PRODUCTION CAPACITIES &