Record of Decision System (RODS)
|Site Name:||KOPPERS COKE|
|Address:||1000 N HAMLINE AVENUE|
|City & State:||ST. PAUL MN 55104|
|NPL Status:||Currently on the Final NPL|
|ROD Type:||Record of Decision|
|Contaminant:||VOCs, semi-VOCs, PAHs, metals, cyanide|
Please note that the text in this document summarizes the Record of Decision for the purposes of facilitating searching and retrieving key text on the ROD. It is not the officially approved abstract drafted by the EPA Regional offices. Once EPA Headquarters receives the official abstract, this text will be replaced.
The 38-acre Koppers Coke site is a former coking facility located in St. Paul, Minnesota. Approximately 15,000 people live within a one-mile radius of the Site. No wetlands or surface-water areas are present except for two small retention ponds orignally developed for dewatering purposes. Two surface water bodies are near the site: Lake Como, about three-quarters of a mile to the northeast of the Site, and the Mississippi River, which is two and three-quarters of a mile to the northwest of the Site and five miles away to the southeast.
Koppers Company, Inc. operated a coking facility at the site from January 1917 to May 1979. On June 16, 1988, Koppers was acquired by Delaware-based BNS, Inc., a subsidiary of Beazer PLC. The facility operated 24 hours a day, seven days a week, and produced foundry coke. By-products of this process included: coal tars and distillates, oils and greases, and liquid and semi-solid wastes. These wastes caused contamination of both the site's soil and groundwater. The primary contamination includes VOCs, semi-VOCs, PAHs, metals, and cyanide compounds. The most significant potential source areas of groundwater contamination at the site include OW-10 Area (West End Disposal Area), G-3 (diesel fuel tank), Area 2 or OW-2 (tank farm), Area 7 (spray pond), Area 8 (effluent sump), Area 9 (sump area adjacent to tank farm), Area 10 (gas holders, benzol washers, and final coolers), Area 11 (tar storage tanks and flushing liquor settling basin), and Area 12 (naphthalene pit).
In 1977 and 1978, Koppers and the Minnesota Pollution Control Agency entered into Stipulation Agreements to correct air quality problems and investigate contamination. Koppers chose to cease operations and demolish the facility structures rather than install the air pollution control equipment required by the 1977 agreement. Demolition was completed in October 1982. The 1978 agreement required Koppers to investigate the extent of soil and groundwater contamination, which it did during 1979. In 1982, MPCA tentatively approved limited site development and purchased the site in October 1982. Under the terms of the purchase agreement, Koppers agreed to dispose of any contaminated soils the MPCA encountered during development of Energy Park. The September 1992 RI outlines that during Phase I of the demolition from May 1979 through January 1980, 20,000 cubic yards of coal tar wastes and contaminated soil were excavated and shipped to an approved hazardous waste landfill in Calumet, IL. Koppers also shipped 2,500 cubic yards of lesser contaminated soil for use in Energy Park road construction. A 1982 evaluation report released by Koppers confirmed the presence of elevated concentrations of major cations and anions and PAHs in the unconsolidated deposits and the Decorah Formation aquifers. Phase II of the facility demolition extended from 1980 through 1981. Underground pipes, demolition debris, and foundations were removed. About 240,000 gallons of tar products from 20 tanks were removed, and 20,000 cubic yards of surface and subsurface soils were shipped to the IL landfill. In 1981, 2,600 cubic yards of contaminated soils were excavated and sent to the IL landfill or for Energy Park road construction. The EPA Remedial Planning/Field Investigation Team submitted a report to MPCA in 1984, which indicated that on-site and off-site groundwater were contaminated with PAHs and VOCs. During the Site Clearing and Grading Phase of the demolition (1982-1983), 85,000 cubic yards of soil were excavated. Some was shipped to the IL landfill, while the less contaminated soil was processed through an asphalt plant. An unknown volume of soil was shipped from OW-10 Area in September of 1982, and another 3,500 cubic yards of soil were processed at an asphalt plant in November 1983. In 1983, 12,100 cubic yards were removed from Area 7 and 4,800 cu yards from Area 8 and shipped to the IL landfill. Also in 1983, 360,000 cubic yards were excavated, with the visibly contaminated soil stockpiled for later disposal at the IL landfill. Uncontaminated soil was used as fill. Another 3,235 cubic yard of soil were excavated during the September 1984 to February 1986 Construction Phase. Some was shipped to the IL landfill, while the less contaminated soil was processed through an asphalt plant. On August 20, 1992, Twin City Testing submitted the Soil Disposal Assessment Report/Work Plan for the First Bank Expansion on the site. Approximately three 5-gallon buckets of soil contaminated with a tar-like substance were removed and are currently being stored on the First Bank's property until an appropriate disposal method can be determined. Approximately 15,000 cubic yards of soil with low levels of contamination (below a level of concern) were placed in a vacant area of the site, adjacent and west of the First Bank building, and covered with 12 inches of clean soil.
This ROD presents the selected remedial action for groundwater (OU1) that has been contaminated by the source areas. Investigations indicate that the glacial aquifer has been impacted by Site releases, but do not conclusively indicate that the bedrock aquifers (Platteville Limestone and St. Peter Sandstone) have been impacted. As part of the implementation of the groundwater remedial action, the MPCA staff will require the RP to conduct additional soil investigations at the Site to evaluate whether additional soil contamination continues to affect groundwater. If so, a ROD for OU2 may be necessary.
|Remedy:||This remedy will be implemented in a phased approach including: pre-design laboratory and field work, including monitoring well decommissioning and replacement, LNAPL investigation, soil and groundwater characterization, microbial characterization, bench-scale nutrient study, and slurry/respirometry study); conducting the phase 1 RD/RA groundwater pilot study; installing about 45 injection wells to deliver oxygen using sparging techniques, and introducing nutrients to the surficial glacial aquifer to promote biological breakdown of contaminants; and implementing the phase 2 RD/RA full-scale groundwater treatment system. If the remedy is not adequate, a groundwater extraction, treatment, and discharge option will be implemented. The RP shall monitor groundwater for a minimum of four years beyond final termination of the treatment system.|
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