The source of the CS-4 groundwater plume is a former motorpool used from 1941 to 1973 and a Defense Reutilization and Marketing Office that operated from 1956 to 1983. Spills, leaks, and disposal at the area have resulted in a groundwater plume.

Primary Contaminants

The four primary contaminants of the CS-4 plume are PCE, TCE, 1,1,2,2-tetrachloroethane (1,1,2,2-TCA), and 1,2-dichloroethylene (1,2-DCE), at levels historically below 100 parts per billion (ppb). The safe drinking water standard, or maximum contaminant level, for each is 5 ppb.

Affected Area

The CS-4 plume extends beyond the southern base boundary west of Sandwich Road, underneath the Crane Wildlife Management Area. It is about 11,250 feet long, 550 feet wide, and 40 to 50 feet thick.

Plume Cleanup

A plume containment system consisting of 13 groundwater extraction wells, a carbon treatment facility, and an infiltration gallery began operation in November 1993. Evaluations of the system completed in 1997 raised questions as to whether the system is effectively capturing the western part of the plume or whether the plume is moving downward just before the containment fence.

Next Steps