THE FLORIDA STEEL CORPORATION (FSC) SITE IS A 150-ACRE FACILITY LOCATED ON HIGHWAY 710 ABOUT 35 MILES NORTHWEST OF WEST PALM BEACH IN MARTIN COUNTY, FLORIDA. FSC OPERATED A STEEL MILL ON THE SITE FROM 1970 TO 1982. ALL OF THE SURROUNDING LAND IS ZONED INDUSTRIAL AND PRESENT LAND USE IN THE VICINITY OF THE SITE IS PRIMARILY UNDEVELOPED. FSC,S PROPERTY WAS UNDEVELOPED PRIOR TO ITS OPERATION OF THE MILL. THE INDIANTOWN MILL USED AN ELECTRIC ARC FURNACE TO RECYCLE SCRAP STEEL INTO NEW PRODUCTS, PRIMARILY STEEL REINFORCING BARS. EMISSION CONTROL (EC) DUST IS THE PRIMARY SITE CON- TAMINANT. FSC DISPOSED OF EC DUST ON-SITE UNTIL NOVEMBER 17 1980 WHEN EPA DETERMINED EC DUST TO BE A TOXIC HAZARDOUS WASTE. GROUNWATER IS CONTAMINATED WITH METALS, AS WELL AS WITH RADIUM, A NATURALLY OCCURING ELEMENT THAT MAY HAVE BEEN CONCENTRATED IN THE GROUNDWATER BY THE DISCHARGE OF A WATER SOFTENING SYSTEM AT THE SITE. IN ADDITION, THERE IS PCB SOIL CONTAMINATION DUE TO LEAKS OF HYDRAULIC FLUID WHICH WAS USED AT THE MILL UNTIL ABOUT 1975. IN DECEMBER 1982, EPA LISTED THE SITE ON THE NPL DUE TO THE EC DUST REMAINING ON- SITE. FSC CONDUCTED THREE CLEANUP ACTIVITIES BETWEEN 1985 AND 1987 TO ADDRESS THE EC DUST AND PCB SOIL CONTAMINATION. DURING EVALUATION OF THE EC DUST, IT WAS DISCOVERED THAT SOILS IN THE VICINITY OF A PROCESS WATER RESERVOIR WERE CON- TAMINATED WITH PCB'S, APPARENTLY DUE TO CONTAMINATED HYD- RAULIC FLUIDS USED AT THE MILL PRIOR