Congressional District # 04
VELSICOL CHEMICAL CORP. (MICHIGAN)EPA ID# MID000722439
Last Updated: February, 2012
The Velsicol Chemical Corp. site is located in Gratiot County, Michigan. From 1936 until 1978, Velsicol (formerly Michigan Chemical Corp.) produced various chemical compounds and products at its fifty-four acre main plant site in St. Louis, Michigan, such as hexabromobenzene (HBB), 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (DDT), polybrominated biphenyl (PBB), and tris(2,3-dibromopropyl) phosphate (tris). In 1982, a Consent Judgment was entered into by Velsicol, U.S. EPA and the State of Michigan, under which Velsicol agreed to construct a slurry wall around and a clay cap over the fifty-four acre main plant site. In return, Velsicol received a broad covenant not to sue from U.S. EPA and the State of Michigan. The Pine River, which borders the main plant site on three sides and was known to contain significant levels of DDT and PBB, was not required to be remediated by the 1982 Consent Judgment. The Pine River contamination was addressed at the time by the State of Michigan with a no-consumption advisory for all species of fish. The fish advisory continues to remain in effect.
Site ResponsibilityThis site is being addressed through federal and state actions.
Threats and ContaminantsOn-site groundwater is contaminated with DDT, chlorobenzene, carbon tetrachloride, trichloroethylene (TCE), and other chlorinated compounds. Onsite soil samples revealed contamination with PBBs, copper, chromium, zinc, and magnesium. The sediments of the Pine River were also contaminated with similar contaminants through direct discharges from the site; however, surface waters do not show any significant impacts. Potential risks exist for people who eat contaminated fish and wildlife in the vicinity of the site.
Cleanup ProgressUnder the 1982 Consent Judgement, Velsicol completed the construction of the containment system at the main plant site in 1985. The containment system consisted of a slurry wall around the fifty-four acre site and a clay cap over the site. The Consent Judgment also required that Velsicol maintain water levels within the containment system at less than 724.13 feet above mean sea level. Water levels within the containment system did not exceed 724.13 until 1993. Velsicol had to pump out 1.25 million gallons of water from the containment system in early 1994 and another 1.28 million gallons in late 1994. EPA and the State of Michigan asked Velsicol to conduct an assessment of the containment system to determine why water levels continued to rise in the system. Velsicol agreed and began the assessment in the summer of 1996 and completed it in March 1997. Velsicol also submitted technical documents to EPA in July 1996 to begin the process for getting approval to inject non-hazardous waste down their deep injection well, which is located five miles from the main plant site. Velsicol constructed an alarm and automatic shut-off system for the deep injection well in 1997. Velsicol received approval from EPA to inject non-hazardous waste down the deep well in 1997.
Around this same timeframe, EPA and the State of Michigan began a reassessment of contamination in the Pine River/St. Louis Impoundment. During summer 1996, sediment cores were collected from 23 locations in the St. Louis Impoundment and analyzed for PBB, HBB, and DDT. Surficial sediment samples also were collected from depositional areas in the lower Pine River (below the St. Louis dam). During summer 1997 the Agencies collected another round of sediment cores from 28 locations and analyzed them for DDT and total organic carbon (TOC). Additionally, the Michigan Department of Environmental Quality (MDEQ) collected fish for analysis.
Results from all sediment surveys indicated that the levels of total DDT in the Pine River and the St. Louis Impoundment were extremely high with a maximum of 32,000 ppm total DDT. A comparison of the 1980, 1981, 1996 and 1997 data showed that the concentration levels, as a whole, had not decreased over time.
On June 8, 1998, EPA signed an Action Memorandum for a time-critical removal action to address the most highly-contaminated sediments in the Pine River. The Action Memorandum called for dredging/ excavating sediments containing 3,000 ppm total DDT or greater (the hot spot), treatment of the sediments with a stabilizing/drying agent, and offsite disposal of the sediments. The removal action also included building necessary infrastructure such as roads, a staging pad, and a water treatment plant. Construction of the infrastructure was substantially complete by November 1998. Sediment removal began in the spring of 1999 and was completed in October 1999.
For the remaining contaminated sediments not addressed by the removal action, a streamlined Remedial Investigation and Feasibility Study (RI/FS) Report and Proposed Plan were made available to the public in August 1998. EPA signed a Record of Decision (ROD) on February 12, 1999, selecting Alternative 4 (Hydraulic Modification of the Pine River, Excavation of Sediments, Dewatering and Water Treatment) and Alternatives 5 and 6 (disposal of contaminated sediments in either a Resource Conservation and Recovery Act Subtitle D or C landfill). The ROD contemplated the use of temporary cofferdams and the dry excavation of sediments, but also recognized that the installation of temporary cofferdams might not be implementable in all locations in the St. Louis Impoundment and that some of the sediment removal might need to be completed using mechanical or hydraulic dredging. In accordance with the ROD, remedial action work in the Pine River would include the following components: installation of temporary cofferdams in the St. Louis Impoundment; dewatering of the areas within the cofferdams; dry excavation of the sediments; stabilization of the sediments with a drying agent; treatment of the water removed from the excavation areas; ongoing monitoring of operations to ensure protection of workers and the community; ongoing water column and air monitoring; and sediment sampling after completion of the excavation work to ensure the completion of the project. In addition, the State of Michigan would continue to monitor fish levels until the fish advisory can be removed.
EPA began Phase I remedial action work in the fall of 1999 with the installation of sheet piling to construct cofferdams and to divide the southern half of the river into manageable cells. Phase I cleanup activities were completed during the 2003 construction season. Within the Phase I area, an access road with 20 seven-foot diameter culverts was built. This access road would later be utilized during the Phase II remedial action activities in order to reach the northern half of the river. EPA began dewatering and sediment removal in the northern half of the river (Phase II) in the summer of 2004 and completed the work in 2005, with the removal of the northern sheet piling completed in early 2006. During the 2006 construction season, EPA again dewatered the southern half of the river so that the in-river haul roads could be removed and the remaining contamination in the equalization basin could be excavated and shipped offsite for disposal. The remedial action work in the river was completed by the end of 2006.
The use of dry excavation methods for cleanup of the Pine River sediments facilitated the discovery that the slurry wall around the 52-acre former plant site was failing, and Dense Non-Aqueous Phase Liquid (DNAPL) was migrating from the main plant site into the glacial till underlying the river sediments. Adaptive change management during the Pine River remedial action handled the discovery of DNAPL without losing construction time. By the end of 2006, a total of approximately 4,355 gallons of DNAPL had been pumped from the river bottom (3,275 gallons of which were pumped out during 2002), approximately 640,000 cubic yards of sediment had been removed, an estimated 222 tons of DDT had been removed from the river, and approximately 1,400 linear feet of interceptor trench had been installed along the riverbank to collect DNAPL migrating from the plant site (including an additional section of interceptor trench installed in 2006 in the area near the former equalization basin). Laterals to the trench were installed to extend into the cells where residual DNAPL within the till was left in place due to the proximity to the lower water table. EPA also constructed a clay cap over the areas of the river bottom with residual DNAPL to isolate the contaminants from the river.
Following the discovery that the slurry wall surrounding the former plant site was failing, the Agencies began an RI/FS at the main plant site, designated as operable unit 1 (OU1). (The Pine River sediment remediation project is designated as OU2.) MDEQ is the lead agency conducting the RI/FS and U.S. EPA is the support agency. MDEQ has included as part of OU1 not only the main plant site, but also adjacent or nearby properties and the "former burn area" at the Gratiot County Golf Course site located across the Pine River. Total site acreage for OU1 and OU2 is estimated to be approximately 100 acres.
MDEQ released the RI Report for OU1 in late November 2006 and held a public meeting to discuss the findings in early December 2006. A copy of the report is available at the St. Louis public library. The report includes the results of site investigation work at the main plant site, as well as at adjacent or nearby properties and at an area known as the "former burn area" on the Gratiot County Golf Course site located across the Pine River. The report concludes that soils and groundwater at the site are contaminated with a variety of chemicals. Soils are contaminated with volatile organic compounds, semi-volatile organic compounds, pesticides, specialty chemicals, and inorganics; the areas with the highest concentrations of contaminants and the most contaminant detections were in the shallow outwash unit soils on the former plant site. Groundwater is contaminated with volatile organic compounds, semi-volatile organic compounds, pesticides, specialty chemicals, and inorganics. Volatile organic compounds are the predominant contaminants present in groundwater at the former plant site in terms of the frequency detected and the concentrations observed, with the highest concentrations detected in the northeast and western portions of the former plant site. The RI Report concluded that remedial activities will be needed to mitigate the soil and groundwater contamination at the site. The final phase of the RI was completed in Jnauary 2009.
MDEQ and U.S. EPA began work on a Feasibility Study to evaluate potential cleanup options for addressing the contamination at the site. In May 2010, EPA and MDEQ presented the possible cleanup options for the site to U.S. EPA's National Remedy Review Board due to the expected cost of the site remedy to be over $25 million. The Feasibility Study was completed in November 2011. The Proposed Plan was issued in February 2012 and the preferred remedy includes the following:
- Installation of a vertical barrier surrounding the FPS to decrease the potential for DNAPL and dissolved-phase contaminants to directly discharge to the Pine River from the shallow unit.
- Installation of a perimeter drain system to capture contaminated groundwater from the shallow unit for treatment and to maintain an inward hydraulic gradient.
- Continued operation of the existing DNAPL/GWCS to capture DNAPL and contaminated groundwater migrating from the shallow unit and prevent recontamination of the Pine River and sediments.
- Installation of an additional (new) DNAPL/GWCS segment as shown in Figure 28 to address possible DNAPL and groundwater contamination from the MW-19 area.
- Implementation of in-situ thermal treatment to address the two DNAPL-contaminated areas. The ISTT system would be operated until the maximum practical volume of DNAPL, defined as 95 percent of the theoretical volume, is achieved. The primary objective for ISTT implementation is to reduce the potential for mobile DNAPL within the FPS to recontaminate the sediments of the Pine River and prevent migration into the lower unit.
- Collection of DNAPL in the lower unit (100 feet bgs) near the WMW-48 location through the use of a collection sump and transportation of collected fluids offsite for incineration.
- In situ chemical oxidation, or excavation with offsite disposal, of up to four potential source areas (75,090 cubic yards). Two potential source areas will be excavated (42,939 cubic yards) to the Csat concentration with subsequent offsite disposal. Two potential source areas (32,151 cubic yards) with groundwater contamination greater than respective water solubility concentrations will be treated by ISCO until the concentration of COCs are below their respective water solubility concentrations.
- Installation of an engineered cap meeting the requirements of RCRA Subtitle C and Michigan Part 111 to eliminate the direct contact threat and prevent infiltration.
- Replacement of the City of St. Louis, Michigan municipal water supply to avoid increased, non-cost-effective long-term groundwater extraction and treatment costs.
- Restoration of groundwater to drinking water standards outside the POC, and containment within the POC through groundwater extraction and treatment.
- Excavation and offsite disposal of soils exceeding 5 ppm total DDT, 1.2 ppm PPB, and 4.4 ppm TRIS in the ANP to address risk to human health and the environment. Excavated properties will be backfilled with clean fill and restored.
- Monitoring well installation and groundwater monitoring program
- Site restoration
- Institutional controls
The MDEQ concurs with U.S. EPA's preferred remedy. After the public comments are addressed, U.S. EPA will devleop a Record of Decision for the former Velsicol plant site. The Record of Decision is expected to be signed by May 2012. Cleanup of the residential properties will likely begin in the summer of 2012.
Community InvolvementA Technical Assistance Grant (TAG) has been issued to the Pine River Superfund Task Force. Monthly meetings are held with the community, EPA and the State to discuss issues associated with the Velsicol site.
ContactsRemedial Project Manager, U.S. EPA
thomas alcamo (firstname.lastname@example.org)
Community Involvement Coordinator, U.S. EPA
AliasesVELSICOL CHEM CORP DUSTMASTERS DIV
VELSICOL CHEMICAL CORP.(MICHIGAN)
VELSICOL CHEM CORP ST LOUIS PLT
VELSICOL CHEM ST LOUIS PT
VELSICOL CHEMICAL MICH