THE SITE IS A FORMER PRIVATE LANDFILL THAT ACCEPTED MUNICIPAL SOLID WASTE, AS WELL AS WASTE FROM NEARBY COMMERCIAL AND INDUSTRIAL CONCERNS. THE PRIMARY CONTAMINANTS OF CONCERN AT THE SITE ARE THE FOLLOWING CONTAMINANTS, WHICH ARE FOUND IN GROUNDWATER BENEATH THE SITE AND IN A GROUNDWATER PLUME EXTENDING AT LEAST 3800 FEET OFF-SITE; BENZENE, CHLOROFORM; 1,2-DCA; TRANS-1,2-DCE; PCE; TCE; AND VINYL CHLORIDE. ON SEPTEMBER 27, 1996, U.S. EPA SENT SPECIAL NOTICE LETTERS TO 58 PRP'S (SOME OF WHICH U.S. EPA MAY RECOGNIZE AS DE MINIMIS PARTIES IN THE FUTURE), OFFERING THOSE PRPS THE OPPORTUNITY TO NEGOTIATE FOR PERFORMANCE OF THE REMEDIAL DESIGN AND REMEDIAL ACTION FOR THE SITE. IN THE RECORD OF DECISION FOR THE SITE, U.S.EPA AND THE WISCONSIN DNR SELECTED THE FOLLOWING REMEDY: MAINTENANCE OF THE EXISTING SINGLE BARRIER CAP OVER THE LANDFILL; OPERA