NATURE OF CASE CONOCO CHEMICALS COMPANY (CONOCO) OWNS AND OPERATES A PLANT IN OKLAHOMA CITY, OKLAHOMA WHICH MANUFACTURES POLYVINYL CHLORIDE (PVC) ONLY BY THE SUSPENSION PROCESS. THE PVC PLANT REPORTEDLY FIRST STARTED OPERATION IN APRIL OF 1971 AND SUBSEQUENTLY HAS COMPLETED TWO SEPARATE EXPANSIONS TO DATE. THIS SUIT IS REQUESTED PURSUANT TO SECTION 113(B)(3) AND (B)(4) OF THE CLEAN AIR ACT. CAUSE OF ACTION FROM APRIL 5,1978 THROUGH MARCH 23,1980, CONOCO'S OKLAHOMA CITY CHEMICAL (PVC) PLANT IDENTIFIED A TOTAL OF 6 VINYL CHLORIDE (VC) DISCHARGES FOR A 166,000 POUNDS OF VC DISCHARGED. CONOCO CHARECTERIZES THESE DISCHARGES AS EMERGENCIES , AN EXCEPTION ALLOWED BY APPLICABLE NESHAP REGULATIONS, TO THE NO DISCHARGE BAN ON THE DISCHARGE OF THIS HAZARDOUS AIR POLLUTANT. REGION 6 DISAGREES, AND VIEWS THEM AS PREVENTABLE DISCHARGES WHICH ARE PROHIBITED. FIVE OF THESE DISCHARGES OF VC WERE REPORTED BY CONOCO AS EMERGENCIES UNDER 40 CFR 61.65(A). REGION 6 FIRST INITIATED INVESTIGATION OF THESE 5 DISCHARGES BY ISSUING A LETTER TO THE OKLAHOMA CITY FACILITY UNDER SECTION 114 OF THE CLEAN AIR ACT, DATED MAY 12, 1981. CONOCO RESPONDED BY LETTER DATED SEPTEMBER 15,1981, AND IDENTIFIED A SIXTH VC DISCHARGE WHICH HAD OCCURRED ON APRIL 5, 1978, AND HAD NOT BEEN REPORTED PREVIOUSLY.