ILN000510194, Superfund Alternative Approach Agreements Sites | Region 5 Superfund

U.S. EPA REGION 5
COOK COUNTY
CHICAGO

Congressional District # 03

PEOPLES GAS THROOP STREET FORMER MGP

EPA ID# ILN000510194
Last Updated: November, 2008

Site Description

The Throop Street Station Former Manufactured Gas Plant (MGP) site is located at the intersection of South Throop Street, South Eleanor Street, and West 25th Street in Section 29, Township 39 North, Range 14 East in Chicago, Cook County, Illinois. The site encompasses approximately 15.5 acres and is bounded to the north by the South Branch of the Chicago River, to the south by South Eleanor Street and West 25th Street, to the west by Loomis Street, and to the east by Commonwealth Edison. The western portion of the site was part of the former South Station but is included in the site because of the common ownership and use. Land use near the site is predominantly industrial and residential. The site is currently owned by Brandenburg Demolition, Inc. (Brandenburg) and is used as a storage yard for equipment and debris. Office buildings, tractor trailers, cranes, construction material, and debris associated with the demolition company are located on-site. Much of the site is covered in crushed rock and gravel. Although environmental conditions at the site have not been thoroughly investigated, surface staining has been observed; this staining may be associated with Brandenburg’s operations or with earlier manufactured gas operations.

The Throop Street Station was constructed in 1892 by Consumers Gas Company as a gas holder facility. MGP structures at the site included three gas holders (with capacities of 4.2 million, 5 million, and 10 million cubic feet) and associated underground water tanks, aboveground tar and oil tanks, exhaust holders, and boiler and pump houses. The Peoples Gas Light and Coke Company (“Peoples Gas”) acquired the site in 1897. The site operated as a manufactured gas storage and distribution facility. In 1944, a mixing plant was constructed to mix manufactured and natural gas on-site. The 4.2 million cubic foot gas holder was retired from service in 1954 and dismantled in 1957. The 5 million cubic foot gas holder was retired by 1963 and the 10 million cubic foot gas holder was retired in 1971. The station was closed in 1972 and sold to Brandenburg in 1981. All above ground structures associated with the gas holder facility have been demolished.

Site Responsibility

The site is being addressed through federal and potentially responsible parties actions.

Threats and Contaminants

Two soil borings were installed in the southwest corner of the site by Burns and McDonnell in 2002 on behalf of Peoples Gas. Black, stained soils exhibiting strong odors were observed beneath the water table and a sheen was observed on the groundwater surface. No ground water samples were collected as part of this investigation and no other site investigation activities have been conducted on-site. The general direction of groundwater flow at the site is expected to be north toward the South Branch of the Chicago River. Site-specific groundwater quality data is not available at this time, but contaminants likely to be present in groundwater at the site include the volatile organic compounds (VOCs) benzene, toluene, ethylbenzene, and xylene (BTEX), polyaromatic hydrocarbons (PAHs), metals, and cyanide.

Limited site investigation activities were conducted in the southwest corner of the site by Hygieneering, Inc., (Hygieneering) in March 2001 and by Burns and McDonnell in June 2002. No subsurface investigation activities have been conducted at the remainder of the site. In the southwest corner of the Throop Street site, Hygiengineering reported the presence of blue-green soils, strong odors, and elevated organic vapor readings in soils. Burns and McDonnell’s investigation revealed the presence of black staining, odors, elevated organic vapor readings, and petroleum sheen on the groundwater surface. Analytical results for soil samples collected in the southwest corner of the site indicate the presence of elevated concentrations of PAHs. No other soil sampling is known to have been conducted at the site and no additional information regarding site-specific soil characteristics is known at this time. Other contaminants likely to be present in site soils include BTEX, PAHs, metals, and cyanide.

The site is adjacent to the South Branch of the Chicago River. Sediment samples were collected from a location in the South Branch approximately 750 feet downstream of the site (adjacent to the South Station Former MGP site) in 2000 as part of an Agency study of sediment contamination. These samples contained high levels of PAHs, polychlorinated biphenyls (PCBs), oil and grease, and metals; the concentrations of these substances generally increased with depth. Many of the reported concentrations of total and individual PAHs, PCBs, and metals suggest toxicity to organisms that live in the sediment (benthic invertebrates). Burns and McDonnell investigated the conditions in the sediments adjacent to the site on behalf of Peoples Gas in 2006. Tar-like impacts were observed in a number of the sediment borings.

Cleanup Progress

The Agency was approached by Wisconsin Public Service Corp. (WPSC) in 2005, to investigate and clean up seven former Manufactured Gas Plants (MGPs) throughout Wisconsin under EPA’s Superfund Alternative Sites (SAS) program. The SAS Program takes sites that might otherwise be eligible for the National Priorities List (NPL), but which will be investigated and cleaned up by a cooperative responsible party, without formally listing the site on the NPL. When WPSC merged with Peoples Energy to form Integrys Energy Group, EPA was approached by Peoples Energy in 2007, to address thirteen former MGPs in Illinois under the same SAS program. The Throop Street Station is one of those thirteen sites.

EPA and Integrys entered into an Administrative Order on Consent (AOC) for Remedial Investigations and Feasibility Studies at the two Waukegan site and an AOC for Engineering Evaluations and Cost Analyses (EE/CAs) at the eleven Chicago sites. Since the twenty sites have similar conditions and contaminants, and Integrys is responsible for each, the agreements allow 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 allow progress on the worst problems first. By the end of 2008, all of the mult-site documents had been approved, and site-specific work had begun on several of the sites. On October 31, 2008 EPA and Integrys entered into an AOC which converted the EE/CA AOC for the 11 Chicago former MGP sites to an RI/FS AOC.

To more effectively manage all 11 original Chicago sites, the RI/FS AOC organizes them into 4 sites: the North Shore Avenue Site, the North Branch Site, the South Branch Site. and the Crawford Site. Both the North Branch Site and the South Branch Site have several operable units. The North Branch Site is comprised of the Division Street Station Operable Unit (OU), the North Station OU, and the Willow Street/Hawthorned Avenue Station OU. One site is the the North Shore Avenue Station Site. The South Branch Site is comprised of the 22nd Street Station Upland OU, the Hough Place Station Upland OU, the Pitney Court Station Upland OU, the South Station Upland OU, the Throop Station Upland OU, and the South Branch River OU.

Investigations and Remediation Previously Performed

The on-site environmental investigations performed to date have been limited to a few borings in the southwest corner of the site in 2001-2002. Conditions in the river adjacent to the site were investigated by installing borings at selected locations in 2006. Evidence of tar impacts (e.g., tar globules, sheen, and odor) was observed at a number of sediment boring locations. Data obtained with a tar-specific green optical screening tool (“TarGOST”) device indicate the presence of coal tar at several locations, and laboratory analysis of sediment samples found high levels of PAHs.

No investigation or remediation of the land portion of the property has been performed to date on behalf of Peoples Gas.

Additional investigation of the remaining contamination will take place under the RI/FS. A schedule for completion of the RI/FS will be established once more information is available to prioritize all 11 Chicago former MGP sites.

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