EPA, REGION IV, FILED THIS CIVIL COST RECOVERY REFERRAL WITH THE DEPARTMENT OF JUSTICE PURSUANT TO SECTION 107 OF CERCLA, REQUESTING THAT DOJ FILE A COST RECOVERY ACTION AGAINST FOUR POTENTIALLY RESPONSIBLE PARTIES (PRPS) TO RECOVER COSTS INCURRED DURING REMOVAL ACTIVITIES CONDUCTED AT TWO SITES. THE SONORA SITE AND THE CARLIE MIDDLETON METAL YARD SITE (THE SITES) ARE LOCATED WITHIN FIVE MILES OF EACH OTHER IN HARDIN COUNTY, KENTUCKY. OVER THE PERIOD BEGINNING IN 1979 AND ENDING IN 1989, THE OPERATORS TRANSPORTED VARIOUS FORMS OF INDUSTRIAL WASTE MATERIALS, INCLUDING TRANSFORMERS AND OTHER FORMS OF ELECTRICAL EQUIPMENT, TO THE SITES. ONCE AT THE SITES, THE OPERATORS SEPARATED VALUABLE METALS FROM THE INDUSTRIAL WASTE MATERIALS BY BURNING OIL AND INSULATION IN OR ON THE WASTES AND BY MANUALLY REMOVING VALUABLE METALS FROM THE RUBBLE. THESE ACTIVITIES RESULTED IN THE RELEASE OF THE HAZARDOUS SUBSTANCES LEAD AND COPPER AT THE SITES. DUE TO THE GEOGRAPHIC PROXIMITY AND THE SIMILARITY OF WASTE STREAMS OF THE SITES, THE SITES WERE TREATED AS SUBSITES FOR PURPOSES OF CONCURRENT REMOVAL ACTIVITIES WHICH WERE CONDUCTED DURING THE PERIOD 1989-1991. THE REFERRAL ADDRESSED COSTS EXPENDED AT BOTH SITES BECAUSE (1) THE SITES WERE COMBINED DURING THE REMOVAL ACTION, (2) OPERATIONS AT THE SITES WERE IDENTICAL AND THE SAME PERSONS OPERATED THE SITES, AND (3) THE DEFENDANTS ARE THE SAME FOR EACH SITE. EPA IDENTIFIED 14 PRPS; HOWEVER, FOR