NATURE OF THE CASE BRIGHTON LANDFILL IS A HAZARDOUS WASTE LANDFILL LOCATED IN BRIGHTON, ILLINOIS. SINCE 1980, THE LANDFILL HAS ACCEPT- ED HAZARDOUS WASTE FOR BURIAL WHILE OPERATING UNDER RCRA INTERIM STATUS. ON SEPTEMBER 28, 1984, U.S. EPA ISSUED BRIGHTON LANDFILL AN ADMINISTRATIVE COMPLAINT AND COMPLIANCE ORDER FOR, AMONG OTHER THINGS, VIOLATIONS OF RCRA GROUND- WATER MONITORING REQUIREMENTS. U.S. EPA AND BRIGHTON LAND- FILL SETTLED THE ADMINISTRATIVE MATTER ON SEPTEMBER 10, 1985 BY ENTERING INTO A CONSENT AGREEMENT AND FINAL ORDER (CAFO). UNDER THE TERMS OF THE CAFO, BRIGHTON LANDFILL IS REQUIRED TO IMPLEMENT A GROUNDWATER MONITORING SYSTEM WHICH MEETS THE APPROVAL OF U.S. EPA. IN JANUARY 1986, U.S. EPA RECEIVED NOTIFICATION THAT BRIGHTON LANDFILL AND THE ILLINOIS ATTORNEY GENERAL HAD ENTERED INTO AN AGREEMENT APPROVED BY A STATE COURT ON DECEMBER 20, 1985 ( JUDGEMENT ORDER ). THE JUDGMENT ORDER CONTAINS PROVISIONS REGARDING GROUNDWATER MONITORING WHICH CONFLICT DIRECTLY WITH THE RCRA GROUNDWATER MONITORING RE- QUIREMENTS TO WHICH BRIGHTON LANDFILL HAD EARLIER AGREED IN THE FEDERAL CAFO. MOREOVER, PROVISIONS OF THE JUDGMENT ORDER REGARDING CLOSURE AND POST-CLOSURE CARE AT BRIGHTON LANDFILL ARE INCONSISTENT WITH THE RCRA CLOSURE AND POST- CLOSURE REQUIREMENTS. SUCH RCRA REQUIREMENTS BECAME APPLI- CABLE TO BRIGHTON LANDFILL ON NOVEMBER