The Sporlan Valve Plant #1 Site consists of an unoccupied four-acre parcel at 611 East Seventh Street in Washington, Franklin County, Missouri, and a groundwater contamination plume originating at the property and migrating beyond the property boundaries. The full extent of this plume has not been identified, but based on groundwater monitoring results, it is known to extend to the south past Eighth Street and to the east past MacArthur Street, traveling beneath residential structures. Vapor Intrusion (VI) sampling conducted in 2015 by the Missouri Department of Natural Resources (MDNR) identified concentrations of TCE that exceeded indoor air screening levels at three residential properties. During this sampling event, four residential properties were identified to have subslab TCE vapor exceeding screening levels.
Currently EPA has a Unilateral Administrative Order with SV Land LLC to install Vapor Mitigation systems in residential homes to the South and East of the Site. In addition, a Removal Site Evaluation is being conducted to determine if a source area can be defined on the former Sporlan property or if any additional homes are threatened from the TCE groundwater plume originating from the Site.
