BY THIS LETTER, THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY(U.S. EPA ) IS TRANSMITTING TO THE DEPARTMENT OF JUSTICE A LITIGATIONREPORT THAT DOCUMENTS VIOLATIONS OF THE CLEAN AIR ACT, 42 U.S C.SECTION 7401 ET SEQ., BY MARATHON OIL COMPANY . MARATHON, THROUGH ITSOWNERSHIP AN OPERATION OF A PETROLEUM REFINERY LOCATED IN ROBINSON,ILLINOIS (REFINERY) , HAS VIOLATED THE CLEAN WATER ACT AND THE STATE OFILLINOIS IMPLEMENTATION PLAN (SIP) RULES GOVERNING OPERATION ANDLIMITING OPACITY AND PARTICULAR MATTER EMISSIONS. ON MARCH 2, 1994, U.S. EPA ISSUED A NOTICE OF VIOLATION (NOV) TOMARATHON FOR THREE VIOLATIONS AT ITS FLUIDS CATALYTIC CRACKINGUNIT-CARBON MONOXIDE BOILER (FCCU-CO BOILER). FIRST, MARATHON EXCEEDEDPARTICULATE EMISSIONS DURING A MAY 12, 1993, STACK TEST, IN VIOLATION OFILLINOIS SIP RULE 212.381 WHICH PROHIBITS THE EMISSION OF PARTICULATEMATTER FROM CATALYST REGENERATORS OF FCCUS IN EXCESS OF AN EMISSION RATEBASED ON THE WEIGHT OF MATERIAL PROCESSED BY THE SOURCE PER HOUR.SECOND, MARATHON EXCEEDED PARTICULATE EMISSION LIMITS AND OPACITY LIMITSAT ITS FCCU-CO BOILER DURING AN AUGUST 4 AND 5, 1993, STACK TEST, INVIOLATION OF ILLINOIS SIP RULES 212.381 AND 212.123. ILLIONIS SIP RULE212.123 REGULATES VISIBLE EMISSIONS OF PARTICULATES MATTER BYPROHIBITING THE DISCHARGE INTO THE ATMOSPHERE FROM ANY SINGLE SOURCE OFEMIS