CONCO INC. (CONCO) OWNS AND OPERATES A PETROLEUM REFINING FACILITY WHICH CONSISTS OF TWO ADJACENT REFINERIES IN PONCA CITY, OKLAHOMA. CRUDE PETROLEUM IS RECEIVED AND PROCESSED INTO A VERIETY OF PETROLEUM PRODUCTS. OFF-GASES RESULTING FROM MANY PROCESS OPERATIONS ARE SENT TO CENTRAL COLLECTION POINTS CALLED FUEL GAS DRUMS. THESE OFF-GASES COMPRISE WHAT IS CALLED FUEL GAS OR FINERY GAS AND USUALLY CONTAIN SULFUR COMPOUNDS SUCH AS HYDROGEN SULFIDE (H2S). THE FUEL GAS IS DISTRIBUTED FROM THE FUEL GAS DRUMS TO PROCESS HEATE- RS TO BE USED AS FUEL FOR COMBUSTION WHICH PROVIDES ENGRY INPUT TO PROCESS OPERATIONS. THREE PROCESS HEATERS ARE IN- VOLVED IN THIS ACTION AND HAVE BEEN IDENTIFIED BY CONOCO AS HEATERS H-59, H-6014, AND H-6015. THESE THREE PROCESS HEATERS ARE SUBJECT TO THE STANDARDS OF PERFORMANCE FOR PETROLEUM REFINERIES CODIFIED IN 40 C.F.R. PART 60, SUBPART J. CONCO OPERATES A FLUID CATALYTIC CRACKING GAS OIL HYDRO- TREATER (FCCGOH) AT THEIR PONCA CITY FACILITY. HYDROTREAT- ING (HYDRODESULFURIZATION) AS THE PROCESS IS USED IN THIS CASE, INVOLVES TAKING GAS OIL FOR THE FCC AND TREATING IT TO REMOVE SUCH IMPURITIES AS SULFUR, NITROGEN, AND METAL COMP- OUNDS. THIS PRETREATMENT PROLONGS CATALYST LIFE AND THE TIME BETWEEN CYCLES IN THE CRACKER. CONCO ALSO OPERATES A CRYOGENIC RECOVERY UNIT (CRU). A SECOND CRU IS PLANNED FOR START-UP ON