SITE IS AN ACTIVE RAILROAD SIDING ORIGINALLY DEVELOPED AROUND THE TURN OF THE CENTURY BY UNION PACIFIC AND DENVER AND RIO GRANDE RAILROAD TO SUPPORT LOCAL SMELTERS AND INDUSTRIAL FACILITIES. DURING THE DEVELOPMENT OF THE RAIL WAY, FILL FROM AN UNKNOWN SOURCE WAS BROUGHT IN AND PLACED BENEATH THE TRACKS. SOIL FILL AT THE SITE CONTAINS ELEVATED LEVELS OF ARSENIC, CADMIUM AND LEAD. THERE ARE 4 OR 5 RESIDENCES ON THE WEST SIDE OF THE SITE AND 23 RESIDENCES ARE ON THE EAST SIDE OF THE SITE. MOST OF THE OTHER PROPERTIES ARE COMMERCIAL OR LIGHT MANUFACTURING FACILITIES. ELEVATED CONCENTRATIONS OF ARSENIC, CADMIUM AND LEAD HAVE BEEN DETECTED IN THE SEDIMENTS IN A PARTIALLY OPEN IRRIGATION DITCH THAT TRAVERSES THE SITE.