EPA designated the Pittsfield plant and several miles of the Housatonic to be a Superfund site in 1997, and ordered GE to remediate the site.[192] Aroclor 1254 and Aroclor 1260, made by Monsanto, was the primary contaminant of the pollution.[193][194] The highest concentrations of PCBs in the Housatonic River are found in Woods Pond in Lenox, Massachusetts, just south of Pittsfield, where they have been measured up to 110 mg/kg in the sediment.[194] About 50% of all the PCBs currently in the river are estimated to be retained in the sediment behind Woods Pond dam.