WARREN RECYCLING, INC., AND WARREN HILLS LLC, OWN AND OPERATE THE WARREN RECYCLING SITE. THE SITE OCCUPIES APPROXIMATELY 200 ACRES, WHICH IS IN CLOSE PROXIMITY TO RESIDENTIAL AREAS AND SCHOOLS. SINCE 1994, THE SITE HAS OPERATED AS A CONSTRUCTION AND DEMOLITION LANDFILL. IN THE FALL OF 2001, THE OHIO ENVIRONMENTAL PROTECTION AGENCY FREQUENTLY RECEIVED CITIZEN COMPLAINTS OF ODOR AND HEALTH PROBLEM FROM THE AREAS SURROUNDING THE SITE. IN 2002, U.S. EPA CONDUCTED INDOOR AND OUTDOOR AIR MONITORING FOR H2S AT SEVEN RESIDENTIAL LOCATIONS. H2S IN THE AIR WAS DETECTED AT LEVELS UP TO 6.1 PARTS PER MILLION IN AIR OUTSIDE THE HOUSES AND 38 PARTS PER BILLION INSIDE. ON APRIL 30, 2004, U.S. EPA COLLECTED TWO TEDLAR BAGS FROM RESIDENTIAL COMMUNITIES NEAR THE FACILITY. ANALYTICAL RESULTS SHOWED CONCENTRATIONS OF HYDROGEN SULFIDE AT .06PPM, DIMETHYL SULFIDE AT .53PPM, DIMETHYL DISULFIDE AT .18PPM, METHYL MERCAPTAN AT .75PPM, AND N-BUTYL MERCAPTAN AT .083PPM. ON OCTOBER 4, 2004, U.S. EPA ISSUED A GENERAL NOTICE OF POTENTIAL LIABILITY TO RESPONDENTS. ON NOVEMBER 2, 2004, AND DECEMBER 29, 2004, U.S. EPA ISSUED A PROPOSED ADMINISTRATIVE ORDER BY CONSENT TO RESPONDENTS. NOW U.S. EPA REQUIRES THE RESPONDENTS TO CONDUCT REMOVAL ACTIVITIES, AND RESPONDENTS SHALL REIMBURSE U.S. EPA, UPON WRITTEN DEMAND, FOR ALL RESPONSE COSTS INCURRED BY THE UNITED STATES IN OVERSEEING RESPONDENTS' IMPLEMENTATION OF THE REQUIREMENTS OF THIS ORDER. VIOLATION OF ANY PROVISION OF THIS ORDER MAY SUBJECT RESPONDENTS TO CI