THE SITE IS LOCATED IN MIAMI, DADE COUNTY, FLORIDA. THE SITE CONSISTS OF SEVERAL PARCELS OF LAND ON WHICH AIRCO DISPOSED OF HAZARDOUS SUBSTANCES GENERATED IN ITS ELECTROPLATING OP- ERATIONS FROM 1957 - 1973.THE DISPOSAL ACTIVITIES CONSISTED OF DISCHARGES OF FOUR WASTESTREAMS GENERATED FROM AIRCO'S OPERATIONS. THE FOUR WASTESTREAMS INCLUDED: 1) A CHROMIC A- CID STREAM; 2) A SODIUM CYANIDE STREAM; 3) AN ACID (SULFURIC AND MURIATIC) AND ALKALI STREAM; AND 4) A CADMIUM, COPPER, ZINC, AND TIN STREAM. THREE UNDERGROUND STORAGE TANKS WERE USED TO COLLECT THESE EFFLUENTS PRIOR TO TREATMENT. THE CHROMIC, CYANIDE AND ACID AND ALKALI STREAMS WERE PLACED IN TANKS FOR TREATMENT. EFFLUENTS FROM THE TREATMENT PROCESSES AND ANY SLUDGE THAT WAS GENERATED WAS ULTIMATELY DISPOSED OF IN THREE UNLINED SEEPAGE PONDS LOCATED AT THE SITE. THE OTHER WASTESTREAM CONSISTED OF A DIRECT DISCHARGE FROM THE PLATING OPERATION INTO THE SEEPAGE PONDS. FROM 1970 - 1986, ON SEVERAL OCCASIONS, THE FLORIDA DEPARTMENT OF ENVIRONMEN- TAL RESOURSES MANAGEMENT (DERM) AND THE FLORIDA DEPARTMENT OF ENVIRONMENTAL REGULATION (FDER) INSPECTED THE SITE AND DETECTED VIOLATIONS OF STATE AND LOCAL ENVIRONMENTAL REGULA- TIONS. FROM 1971 - 1992, EPA INSPECTED THE SITE ON SEVERAL OCCASIONS. THESE INSPECTIONS CONFIRMED, AMONG OTHER THINGS, THE DISPOSAL OF WASTEWATERS CONTAINING CYANIDE, CHROMIUM, CADMIUM, COPPER, ZINC, AND TIN INTO THE PONDS, AND THE PRE- SENCE OF HAZARDOUS SUBSTANCES INCLUD