Elmont Online

WATERVLIET -- A sprawling World War II-era dump at the Watervliet Arsenal has been cleaned enough to present no threat to public health or the environment, the state Department of Environmental Conservation said.

DEC is proposing to remove the arsenal's "Siberia Area," a 15-acre fenced dump south of Watervliet Junior-Senior High School, from a state list of inactive hazardous waste sites, where it has been included since 1987.

This change would come as the Army, which operates the 140-acre arsenal, has agreed to open 60 unused acres for private development. Removing the dump from the hazardous waste list would relieve the state of responsibility for continuing to monitor groundwater, and transfer that role to the Army under the federal Resource Recovery and Conservation Act.

Beginning in the early 1940s, arsenal workers used the dump for a variety of waste oils, solvents, metals and other materials. Other wastes were burned in an open pit at the site.

Subsequent tests of groundwater and soils in the 1990s found the presence of PCBs, mercury, chromium, cadmium, barium, arsenic, iron, lead, xylene, vinyl chloride and other toxic substances.

According to a 2008 DEC report and the Army, cleanups done between 1997 and 2007 included removal of about 20,000 cubic yards of contaminated soil; the use of "biological agents, such as bacteria or plants, to remove or neutralize contaminants"; capping of areas with asphalt or gravel; and installation of a reactive underground wall in 1998 to intercept tainted groundwater.

The Army paid for the cleanup and will be responsible for monitoring groundwater on the site, with annual reports filed with the state, said DEC spokesman Rick Georgeson. No dollar figure for the cleanup work was immediately available.

The 2008 DEC report also found contaminated groundwater was not leaving the area, and that three tests of soil gas samples at the north end of the site -- near the high school and a residential neighborhood -- did not exceed safety limits.

"Direct contact with contaminants in the soil of the Siberia area is unlikely because soil removal actions have been completed and soil contamination remaining on site is covered by clean soil, gravel or asphalt," according to DEC site health assessment.