Koppers Co., Inc. (Charleston Plant)

• Site Profile
• Administrative Record Index (All PDF): OU1 (25 pp., 1.5M), OU1 ESD (2 pp., 123K)
• Additional Site Documents including Five Year Reviews, Records of Decisions (ROD) and Explanation of Significant Differences (ESD).
• For documents not available on the website, please contact the Region 4 Freedom of Information Office (http://www.epa.gov/region4/foiapgs/submit.htm).

Site Background:
The Koppers Co., Inc. site is approximately 102 acres in size and is located in the neck area of north Charleston, South Carolina on the west side of the peninsula formed by the Ashley and Cooper Rivers. Wood-treating operations were conducted on-site by the Koppers Company from 1940 to 1978. Wood-treating operations consisted primarily of treating raw lumber and utility poles with creosote. For short periods of time, pentachlorophenol and copper chromium arsenate were also used as preservatives in the wood-treating processes. The plant treated utility poles, foundation pilings for building docks and wharfs, railroad ties and other construction materials. Under an Administrative Order by Consent with EPA, Beazer East, Inc. (formerly Koppers) completed the RI/FS at the site in December 1996. On-site soils are contaminated with Polynuclear Aromatic Hydrocarbons (PAHs), pentachlorophenol with trace amount of dioxin, arsenic and lead. Creosote has been observed in the sediments and surface waters of drainage ditches leading from the site. Free creosote product has been discovered in the groundwater at three locations underlying the site. Sediments in the Ashley River and neighboring tidal marshes have demonstrated toxicity to ecological receptors. The area surrounding the site is primarily industrial, but the Rosemont residential community is located approximately 1/4 mile north.

Cleanup Progress: Actual Construction Underway
While a final site-wide remedy was developed, EPA issued an Interim Action Record of Decision (ROD) in March 1995 to mitigate off-site migration of contaminants and to eliminate potential exposure to sediments/surface waters of several drainage ditches. Beazer East, Inc. implemented the Interim Action via a Unilateral Administrative Order with EPA. Physical construction began in August, 1996 and full scale operation of the interim action extraction wells began in January 1997.  The ROD for the final remedy was issued on April 1998.  The remedy required excavation and off-site disposal of soil; installation of a cap over contaminated soil; reconstruction of drainage ditches; continued recovery of groundwater and creosote; covering of Ashley River sediments via enhanced sedimentation; and restoration of disturbed tidal marshes.   Two Explanation of Significant Differences (ESDs) were issued to the April 1998 ROD.  An ESD was issued in August 2001 that changed the Ashley River remedy from enhanced sedimentation to placement of an engineered, subaqueous cap.  In April 2003, an ESD was issued for the Barge Canal and Northwest Corner of the site.  This ESD changed the Barge Canal remedy from placement of an engineered subaqueous cap, to natural deposition and monitored natural recovery; and changed the groundwater/creosote component for the Northwest Corner from active creosote recovery with extraction wells to immobilization using stabilization and solidification techniques. 

Physical construction was completed at the Koppers-Charleston site in September 2003, at an estimated cost of $20.4 million.  In general, this involved the following components; excavation and off-site disposal of 22,000 tons of impacted soils; installation of a 40 acre protective cap over surface soils; reconstruction of 3,600 linear feet of surface water drainage ditches; excavation and restoration of the North and South Tidal Marshes; installation of a 3 acre cap over Ashley River sediments; Monitored Natural Recovery for Barge Canal sediments and active recovery of groundwater and creosote underlying the former treatment area and old impoundment area.