THE CLARK FORK BASIN SUPERFUND SITES ARE A SERIES OF FIVE GEOGRAPHICALLY CONNECTED SUPERFUND SITES IN SOUTHWESTERN MONTANA. THE SILVER BOW CREEK/BUTTE AREA (ORIGINAL PORTION) SUPERFUND SITE (SBCO) IS PART OF THE CLARK FORK BASIN COLLECTION OF SUPERFUND SITES. THE SITE BEGINS AT THE HEADWATERS OF SILVER BOW CREEK NEAR BUTTE IN SOUTHWEST MONTANA, PROCEEDS DOWN SILVER BOW CREEK TO THE WARM SPRINGS PONDS, WHERE IT NOW ENDS. AT ONE POINT, THE SITE CONTINUED DOWN THE CLARK FORK RIVER TO THE MILLTOWN RESERVIOR FIVE MILES EAST OF MISSOULA. MINING, MILLING AND SMELTING ACTIVITIES, CONDUCTED FOR OVER 100 YEARS IN THE AREA, PRODUCED SUBSTANTIAL QUANTITITIES OF WASTE CONTAMINATED WITH HEAVY METALS. THESE WASTES WERE DISCHARGED OR DUMPED INTO SILVER BOW CREEK, WARM SPRINGS CREEK, AND THE CLARK FORK RIVER. THE CONTAMINATED WASTE ENTERED THE RIVERS IN THE FORM OF SUSPENDED SEDIMENTS PRIMARILY FROM TAILINGS AND SMELTER WASTE AND DISSOLVED METALS PRIMARILY FROM ACID MINE WATER. THE WASTES CONTAIN CONCENTRATED ARSENIC, LEAD, CADMIUM, ZINC, AND COPPER, AS WELL AS OTHER METALS. IN ADDITION TO CONTAMINANTS FROM THE BUTTE MINING OPERATIONS, THE MONTANA POLE AND ROCKER WOOD TREATING FACILITIES CONTRIBUTED TO THE CONTAMINANT LOAD OF SILVER BOW CREEK. BOTH WOOD TREATING OPERATIONS USED PENTACHLOROPHENOL AND CREOSOTE WHICH SEEPED INTO SILVER BOW CREEK. THE ROCKER PLANT SITE ITSELF