Background/ History
The Dow Chemical Co. site is located on 169 acres at 500 Dow Industrial Drive in Pevely. The active facility is located in the northwest portion of the property and is largely covered with buildings, roads, and asphalt parking lots. The facility was built in 1956 and began operations in 1957 producing Styrofoam® brand insulation. From 1975 to 1983, Dow produced Tyril® styrene-acrylonitrile resins. Dow also produced Deraspan® from 1976 until 1981, when it was discontinued. Styron® polystyrene resin, a Dow polymer in the production of Styrofoam®, has been produced at the facility since 1975.
A variety of hazardous wastes are produced as part of the facility operations. Dow stored the hazardous wastes in containers in two storage areas before shipping off-site for disposal. Dow operated the hazardous waste storage areas under the “interim status” portions of the federal Resource Conservation and Recovery Act (RCRA). Currently, the main business at the facility is the manufacture and shipment of Styrofoam® (expanded polystyrene foam insulation) and Styron® (polystyrene pellets). The facility no longer stores hazardous waste at the site for more than 90 days. The containers are managed under generator storage requirements in 10 CSR 25-5.
Cleanup Summary
In 1994, Dow decided to close the hazardous waste storage unit according to their approved interim status closure plan. The department accepted Dow ’s closure certification for the hazardous waste storage areas in 1988 and 1995. Dow is not subject to the permitting requirements of the Missouri Hazardous Waste Management Law or federal Hazardous and Solid Waste Amendments for post-closure care because they “clean closed” the interim status hazardous waste areas.
DOW is subject to corrective action because they completed closure of the interim status hazardous waste management units after the effective date of the federal Hazardous and Solid Waste Amendments. Initial investigations confirmed the soil and groundwater are contaminated with volatile organic compounds, semi-volatile organic compounds and some metals. On November 22, 2006, the department and DOW voluntarily entered into a Letter of Agreement, in an effort to simplify and streamline the corrective action process. The department approved Dow’s RCRA Facility Investigation in June 2011; however, additional investigation was recommended to delineate the extent of metals in the soil and contaminants of potential concern. It was also recommended that a more intensive groundwater investigation be performed. On June 24, 2013, the department approved DOWs Phase 1 Facility Investigation report and provided comments on a Phase 2 work plan for conducting additional investigations at the site.
