Congressional District # 06
WPSC TWO RIVERS MGPEPA ID# WIN000509953
Last Updated: May, 2012
The WPSC Two Rivers former MGP ("Two Rivers") site is located near the West Twin River in Two Rivers, Wisconsin. Manufactured Gas Plants (MGPs) were industrial facilities that produced gas from coal, oil, and other feedstocks. The Two Rivers site totals about 7 acres in size, with about 5 acres on land and about 2 acres of potentially contaminated sediment found in an adjacent stretch of the river.
The Two Rivers site is located in an historically light industrial and riverfront area of the city. The majority of the site is wetlands near the river shore and is accessible by water. The former MGP building and foundations of other structures are still present on the site.
MGPs started operating in the United States in the early 1800s, typically in urban areas where gas was needed for lighting, cooking, and heating. The Two Rivers MGP was operated from 1925 to 1946. Two gas production methods were used at the MGP facility: coal carbonization and carbureted water gas. Both processes produced waste and by-products such as tars, oils, sludges, and acidic waste. Disposal of waste and spills and leaks often resulted in contaminated soil and groundwater at MGP sites. MGPs were often located near waterbodies and thus sediment contamination is also commonly found.
Wisconsin Public Service Corporation (WPSC), an operating utility company, is a potentially responsible party for several former MGPs located throughout Wisconsin, including the Two Rivers site. WPSC is addressing six of its former MGP sites under the Superfund alternative site approach.
The WPSC Two Rivers former MGP site is being addressed through potentially responsible party (PRP) actions under state and federal oversight.
Threats and Contaminants
Soil, groundwater and sediment at former MGP sites are often contaminated. Soil contaminants at the Two Rivers site include polynuclear aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs) including a group of VOCs called benzene, toluene, ethylbenzene, and xylene (BTEX), plus trimethylbenzene, and cyanide. Groundwater at the site flows to the southwest toward the West Twin River. Groundwater contaminants include PAHs, cyanide, napthalene, and BTEX. Sediment in the nearby West Twin River contains PAHs and BTEX contaminants and shows evidence of odor, sheen and/or tar associated with MGP wastes.
People could be exposed to MGP wastes at the Two Rivers site by dermal contact with contaminated soil or river sediment or by drinking contaminated groundwater. Benthic (bottom-dwelling) organisms could be exposed to sediment contaminants in the river. Exposure to the MGP contaminants could cause toxic health effects. However, because residents and nearby businesses use the city water supply for drinking, no one is drinking contaminated groundwater from the site. The potential for exposure to contaminated soil has lessened because a limited soil cleanup action was conducted in the 1990s. Further remedial investigation is necessary to deduce and eliminate other exposure routes to MGP wastes.
WPSC and EPA entered a settlement agreement in May 2006 to address site conditions at six former MGP sites in Wisconsin, including the Two Rivers site. Under the agreement, WPSC has agreed to conduct remedial investigations and feasibility studies at each of the former MGP sites. Because the six sites have similar conditions and contaminants, and WPSC is a potentially responsible party (PRP) for each, the agreement allows a streamlined approach to site investigation and remedy development. Some benefits of the agreement include the use of multi-site documents, a mechanism to review the adequacy of past work, and scheduling flexibility to address the worst problems first.
Prior to this agreement, various investigations of the Two Rivers site were conducted in the 1990s and early 2000s under the Wisconsin Voluntary Cleanup program. Most recently, WPSC conducted a pilot test of in-situ (in place) chemical oxidation of contaminated groundwater from 2003 through 2005; however, the pilot test failed and a new approach for groundwater cleanup was recommended. Routine groundwater monitoring occurs annually.
WPSC will conduct additional investigations of remaining site contaminant levels beginning in 2014 in accordance of the terms of the enforcement agreement with EPA.
ContactsRemedial Project Manager, U.S. EPA
margaret gielniewski (firstname.lastname@example.org)