The U.S. Environmental Protection Agency (EPA) Region 5 invites the public to comment on the Proposed Remedy for the former Tecumseh Products Company (TPC) Facility in Tecumseh, Michigan. The Proposed Remedy includes groundwater treatment, soil treatment and excavation, and institutional controls to prevent future exposures.
The former TPC Facility once occupied approximately 750,000 square feet of buildings on approximately 53 acres of land. TPC has used the Facility since 1934 for the manufacturing of automotive parts, refrigeration systems, small tools and toys, and reconditioning of compressors and condensing units for refrigeration. Manufacturing processes conducted at the Facility included parts degreasing, unit assembly, paint preparation, unit painting, unit reconditioning and shipping and receiving, which continued until operations ceased at the Facility in June 2008.
The use of solvents in degreasing, and the storage of hazardous waste solvents and paints under the Resource Conservation and Recovery Act (RCRA) resulted in releases of contamination to the property and some of the surrounding area. Under an EPA legal order, TPC has been testing the groundwater (underground water), soil gas (underground air), soil, and indoor air at and around the property on Patterson Street since 2009. Initial work identified that contaminated groundwater extended off-site and TPC undertook efforts to locate and decommission water wells within the area of contamination, and connected affected residents to the municipal water supply. TPC also helped the City of Tecumseh develop a Groundwater Use Ordinance to prevent the use of groundwater in the affected area. Further work focused on “vapor intrusion”, which occurs when contaminated underground water gives off gases that can rise through the soil and into buildings through foundation cracks, possibly causing unsafe indoor air quality. Chemicals called “volatile organic compounds,” or VOCs, are especially prone to vapor intrusion, and were the main chemicals used at the TPC site. After addressing these concerns, efforts focused on options for cleanup.
TPC has been evaluating the conditions to prepare a cleanup plan that eliminates the risks from potential exposure to contamination. The investigation was conducted in the multiple phases, resulting in the following:
- 288 temporary soil borings
- 66 Membrane Interface Probe borings
- 76 permanent groundwater monitoring wells
- 26 soil gas locations
- 19 Permeable Reactive Barrier well
A conceptual site model (CSM) was developed based on the nature and extent of contamination and investigation data. The CSM evaluated potential exposure pathways, and identified potential receptors. As concerns were identified, they were addressed through Interim Remedial Measures, including:
- A Groundwater Ordinance
- Well Decommissioning/Municipal Hookup
- 7 Off-site Sub Slab Depressurization Systems
- 2 On-site Permeable Reactive Barriers
- 2 On-site Soil Vapor Extraction Systems
- Soil Source Excavation
- Facility Restrictive Covenant
Purpose of cleanup
The EPA legal order requires TPC to demonstrate that pollution from its facility related to contaminated soil, contaminated groundwater, and contaminated air is not a health risk. People can be exposed to contamination by ingesting, inhaling, contacting the contamination directly, and the purpose of the cleanup is to prevent those exposures from happening.
Trichloroethene and other VOCs were detected above EPA Regional Screening Levels (RSLs) in on-site soil samples. Soil will be remediated to site-specific levels using soil vapor extraction (along with excavation) in four areas, to supplement two prior cleanup areas. The goal is to reduce contamination to levels that prevent additional off-site migration of groundwater contamination, and eliminate the off-site vapor intrusion potential. Residual contamination will be managed on-site with a restrictive covenant, a soil management plan, impermeable surfaces, and vapor mitigation controls for buildings used in the future to protect visitors and site workers following redevelopment.
Groundwater sampling shows two narrow bands of contamination coming from the property. The City Groundwater Ordinance eliminates the ingestion risk by preventing people from drinking contaminated groundwater. However, since contaminated groundwater also extends under some houses in the community, TPC proposes enhanced in-situ bioremediation of the groundwater to reduce
contamination to levels that eliminate the threat of vapor intrusion into buildings above the off-site groundwater plume, followed by monitored natural attenuation. The short-term goal is to eliminate off-site vapor intrusion concerns; the long-term goals are to protect the wetland to the east, and restore the aquifer.
Cleanup levels for individual chemicals in soil and groundwater are the site-specific, pathway-specific cleanup objectives shown in the Statement of Basis.
A site-specific TPC risk assessment for the Facility identified unacceptable risks, and the cleanup proposal is designed to eliminate all unacceptable risks.
- 5 On-site Groundwater EISB Treatment Cells.
- On-site SVE System Expansion in 3-4 Areas
- Soil Excavation/Disposal from 4th Soil Area.
- Existing Building Sub Slab Depressurization
- Vapor Intrusion Controls on New Buildings
- Contaminated Soil Management
- Site Use Restrictions
- Monitored Natural Attenuation Off-site
For More Information
A public meeting will be held Wednesday, Nov. 7, 2018 from 6:00 to 7:30 pm at the Tecumseh Fire Station at 101 E. Russell Road.
EPA's Administrative Record and related documents are available: Hazardous Waste Cleanup:Tecumseh Products Company Facility - Tecumseh, Michigan EPA will make a Final Decision on the Proposed Remedy after the public comment period ends and all comments are reviewed. EPA may modify the Proposed Remedy based on any new information and comments from the public.
Comments or requests for information must be submitted prior to the expiration of the public comment period, which ends November 25, 2018.