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Congressional District # 11


EPA ID# ILD062340641
Last Updated: December, 2011

Site Description

The DePue/New Jersey Zinc/Mobil Chemical Site is located in the Village of DePue, Bureau County, Illinois, and consists of approximately 950 acres. According to the 2010 Census, the Village of DePue's population is 1,838.

The primary zinc smelting facility on the site began operations in 1903 on 175 acres of farmland, but expanded to more than 860 acres over the years as additional plants were added. The original plant produced slab zinc, used in the automobile and appliances industries, and sulfuric acid. Zinc dust was also produced and used as an additive to produce corrosive-resistant paints. In 1967, in response to the increase in the demand for phosphate fertilizer, DePue/New Jersey Zinc constructed a diammonium phosphate (DAP) fertilizer plant. Mobil Chemical leased the DAP and sulfuric acid plants from New Jersey Zinc in 1972 and later purchased the plant in 1975. Due to economics, Mobil ceased manufacturing operations at the plant in August 1987 and the plants were demolished in April 1991.

Two preliminary site assessments were completed in 1980 and 1983, followed by site inspections in 1984 and 1987. Illinois Environmental Protection Agency (IEPA) conducted an expanded site inspection in March 1993 to gather additional soil, sediment, wastewater, and surface water samples. Based on those evaluations and sampling results, IEPA signed an Interim Consent Order with a group of Potentially Responsible Parties (PRPs) known as the DePue Group on November 6, 1995, to perform various investigations and cleanup actions at the site. The DePue Group, which represents former owners and/or operators of the site, consists of ExxonMobil and CBS Corporation (formerly Viacom). In 1999, U.S. EPA formally added the DePue/New Jersey Zinc/Mobil Chemical Superfund Site to the National Priorities List.

To facilitate the investigation and cleanup of contamination, the site has been broken into five (5) areas known as Operable Units, as follows:

• Operable Unit 1, The South Ditch
• Operable Unit 2, Phosphogypsum Stack Area
• Operable Unit 3, The Former Plant Site Area
• Operable Unit 4, Off-Site Soils
• Operable Unit 5, DePue Lake Sediments and Floodplain

IEPA is the lead enforcement agency for the site.

Site Responsibility

The site is being addressed through IEPA and potentially responsible parties' (PRPs') actions.

Threats and Contaminants

Several sources for the contaminants have been identified: a residue pile, a zinc slag pile, lithopone waste material ridges, a cinder fill area, contaminated soils, cooling ponds, a discharge ditch, and the gypsum stack. All sources were found to contain elevated levels of metals including zinc, lead, arsenic, cadmium, chromium, and copper. Contamination of a, state wildlife refuge, and wetlands has been documented in Lake DePue.

Cleanup Progress

The November 1995 Interim Consent Order required the DePue Group to conduct some limited response actions and a Remedial Investigation/Feasibility Study (RI/FS) for the site. The limited response actions included securing the previous manufacturing facility, performing a rigorous dust monitoring and dust control program, and constructing a water treatment plant to treat surface water leaving the plant property and discharging into Lake DePue. The site was secured and dust control implemented during the summer of 1995. In June 1997, the DePue Group completed the construction of the water treatment plant, and it began operating on June 11, 1997. The Interim Consent Order established two sets of discharge limits for the water leaving the treatment plant and for the water entering the lake. The DePue Group was required to meet the second set of limits three years after the interim water treatment plant began operation. On June 11, 2000, the DePue Group finished work at the water treatment plant, as required by Interim Consent Order. The DePue Group has since been operating the water treatment plant.

Several of the Operable Units (OUs) at the site are in the RI/FS phase. During the RI, data is gathered to determine the nature and extent of contamination as well as the risks posed by the contamination. The FS evaluates potential cleanup options. The recent activities and status for each OU at the site are described below.


IEPA conducted an RI/FS in the summer of 1997 to determine the nature and extent of the contamination and to evaluate various cleanup alternatives. In October 2003, the interim cleanup plan or Record of Decision (ROD) addressed the unnatural sediments found on the site during previous IEPA investigations. Cleanup objectives included: reducing the potential for floodwater and water discharges to the South Ditch; mitigating acute exposure risk to sensitive ecological and human receptors; preventing onsite trespass; and mobilizing the unnatural sediments. The ROD selected the removal of contaminated sediment with on-site consolidation. The cleanup for OU1 was completed on June 20, 2006. Although the ROD for OU1 was considered an interim ROD, another ROD for OU1 is not anticipated. Rather, the final remedy for OU1 will be selected as part of the OU5 remedy selection process. 

The first Five-Year Review Report for the DePue/New Jersey Zinc/Mobil Chemical Site was completed on June 25, 2010. The subject of the five-year review was the interim remedial action that had been completed at OU1. The results of the review indicated that the interim remedy at OU1 is protective of human health and the environment in the short term because access to the South Ditch is restricted by a fence and the metals-contaminated sediments that were removed are stored at OU3 in a Corrective Action Management Unit (CAMU) to contain the metals. In order for the remedy at OU1 to be protective in the long term, the remedy selection process for OU5 must be completed and implemented.


The cleanup for OU2 is addressed under Illinois State Landfill Closure regulations. The stack was capped and vegetated. An engineered treatment wetland was constructed adjacent to the landfill as part of the landfill closure. A pilot test to change the vegetative cover from Kentucky 31 fescue (a potential source of fungus to grazing animals) to native prairie habitat is ongoing.


Much of the plant operations took place at OU3. The zinc smelting process produced slag waste, which was stored on-site. Currently, the slag pile is an estimated 65 ft high and one-fourth of a mile long containing various metals and 750, 000 tons of zinc. The water treatment plant operated by the DePue group is also on site. The plant treats water from the lift station for copper, zinc, manganese and low pH. In 2010, a total of 229,000 pounds of zinc, manganese and copper were removed from 24 million gallons of water prior to discharge.

Phase I of the RI/FS at OU3 has been completed and the Phase II RI report is scheduled to be submitted in early 2012. 


The removal assessment sampling results from the off-site soils showed that off-site soils were generally below the “Removal Action Level” for lead (1200 mg/kg) and pertinent removal action levels for other metals. IEPA has therefore decided that the off-site soils do not warrant an immediate removal action. There is, however, sufficient information available to indicate that cleanup of some off-site soils will be required. IEPA and the DePue Group are currently developing plans to address the sampling and cleanup of the off-site soils. 


Lake DePue sits to the south of the Village of DePue and receives both contaminated surface water and groundwater discharged from the plant property. RI sampling began in July 2006 and was completed in the fall of 2007. The DePue Lake RI Report was finalized in July 2009. Results indicated that concentrations of metals (zinc, cadmium, copper, lead, etc.) are elevated. The highest concentrations of these metals were located near the South Ditch discharge area and south of Division Street.

The Illinois Department of Natural Resources (IDNR) has issued an advisory to limit consumption of catfish and carp to 1 meal per month of any size, and 6 meals/year of fish less than 24 inches. Please see the 2011 Illinois Fishing information booklet from IDNR for more detailed information. The fish advisory is the result of PCB contamination; these contaminants are not related to the DePue Site.

IEPA has placed complete copies of the OU5 RI Report, maps, and all data sets in the public repository at the DePue Public Library. IEPA anticipates completion of the risk assessment in early 2012. 


As mentioned above, a five-year review was completed in June 2010 to evaluate the interim remedial action that had been completed at OU1. (See OU1 section above for more information.) A site-wide protectiveness statement could not be made because remedy selection and remedial actions have not been initiated at all operable units of the Site.


Success Story

The site was a barren, slag-covered 150+ acres in the middle of town in 1995 when the Interim Consent Order was signed. The IEPA considered the barren contaminated soil to represent a potential source of airborne particulate exposure. To assess and reduce this potential, an extensive long-term airborne particulate monitoring program was initiated along with revegetation of the major land mass of the former plant site. No risk or airborne contaminated particulate release has been noted in the sampling program.

The interim water treatment plant, constructed in 1996 and brought fully into compliance with state and federal discharge standards in 2000, has substantially reduced discharges of contaminated water to DePue Lake. This unit removes, for off-site disposal, in excess of 72,000 pounds of zinc, 5,400 pounds of manganese and 2,000 pounds of copper annually.

Community Involvement

The Village of DePue residents formed a Citizens’ Advisory Group and hosted two Lake Festivals with the IEPA Bureau of Water outreach programs in 2002 and 2004. The CAG currently meets monthly.

The land use committee guiding the Superfund Redevelopment Initiative Pilot Project relied on the participation of 13 active DePue residents. On an annual basis, the IEPA issues a DePue/New Jersey Zinc/Mobil Chemical Site Fact Sheet summarizing activities at the site. The current mailing list for IEPA’s DePue Fact Sheets include all 600 registered postal customers in DePue and an additional 180 households that have attended public meetings or otherwise expressed interest in the project. All fact sheets are written in both English and Spanish and one or more bilingual individuals attend all public meetings to provide translation support.

The DePue/New Jersey Zinc/Mobil Chemical Site is an Environmental Justice Site and managed accordingly by the IEPA.

Property Reuse

A Superfund Redevelopment Initiative Pilot Project was completed under a U.S. EPA grant in August 2004 and involved a broadly-based committee to guide the effort. The result of this redevelopment project was an assessment of viable potential future land uses and village-wide projects. 


Remedial Project Manager, U.S. EPA
colleen moynihan (moynihan.colleen@epa.gov)
(312) 353-8196

Community Involvement Coordinator, U.S. EPA
patricia krause
(312) 886-9506




Site Profile Information

This profile provides you with information on EPA's cleanup progress at this Superfund site.


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