In 1991, EPA excavated and disposed of an on-site waste filter clay pile. In 1997, EPA posted warning signs on the Henry Hudson Trail which is located near the site and the tarp covering the remaining waste filter clay pile was replaced to prevent human contact and limit the migration of the contamination. Arsenic and metals continued to be found in soils in the vicinity of this site. In April 2002, EPA excavated and disposed of a by area of soil containing a tar-like material discovered outside of the fenced area. The presence of elevated levels of PCBs and lead in this material may have presented a physical contact threat to trespassers. In April 2004, 18,000 cubic yards of contaminated soil were removed from Birch Swamp Brook and adjacent properties. In August 2007, EPA arranged for