TITTABAWASSEE RIVER, SAGINAW RIVER & BAY
On this page:
- What Is Being Done to Clean Up the Site?
- What Is the Current Site Status?
- EPA’s Involvement at the Site
- Operable Units (opens new page)
- Cleanup Progress (opens new page)
The Dow Chemical Company facility in Midland, Michigan, began operating in 1897. The 1,900-acre facility abuts the Tittabawassee River; most of the plant is located on the east side of the river and south of the city of Midland. At various times, the Midland Plant produced over 1,000 different organic and inorganic chemicals. Dioxins and furans were byproducts formed during the manufacture of chlorine-based products, including chlorophenolic compounds manufactured at the plant since the 1930s. Elevated dioxin levels in and along the Tittabawassee River and downstream appear to be primarily attributable to liquid wastes that were discharged in the past directly into the river from the facility.
Past waste disposal practices at the Midland Plant have resulted in on and off-site contamination that settled in some sediment and built up in some riverbanks and floodplain areas. Off-site contamination extends over 50 miles downstream through the Tittabawassee and Saginaw Rivers and into Saginaw Bay.
What Is Being Done to Clean Up the Site?
The site is being addressed through federal, state and potentially responsible party (PRP) actions.
What Is the Current Site Status?
To manage the cleanup, the Tittabawassee River has been divided into seven segments ranging in length from three to four miles. Work is being done in stages from upstream to downstream, segment by segment.
Segment 1, a 3-mile stretch next to the Midland Plant, is the most upstream segment. Cleanup started in 2012 and finished in 2013. The Segment 1 cleanup removed and treated dense non-aqueous phase liquid (DNAPL). A containment system was installed in three areas of Segment 1 to isolate contaminated sediment. After cleanup, the area will be monitored and cleanup systems will be operated and maintained.
Segment 2 is a four-mile stretch of the river below the Midland Plant. The cleanup plan builds on previous work, removing contaminated sediment in some areas and stabilizing contamination to stop it from moving in others. Nearly 23,000 cubic yards of contaminated sediment was removed and about 2.3 acres of contaminated sediment was isolated and contained. Close to a mile of riverbank was stabilized to keep eroding contaminated soil from washing back into the river. Additional work is ongoing in Segment 2 in 2015.
Segment 3 is a four-mile stretch of the river that starts about seven miles below where the Chippewa River meets the Tittabawassee River. EPA recently proposed a plan to clean up dioxin-contaminated sediment and riverbanks in Segment 3. EPA is currently collecting comments on the proposed plan. EPA will select a final remedy after reviewing the comments.
In 2015, EPA selected a
cleanup planfor contaminated soil in frequently flooded areas along the
Tittabawassee River. Many properties in the
Tittabawassee River floodplain will be affected by EPA's cleanup decision. The
multi-year floodplain cleanup will start in 2015. The floodplain includes about 4,500 acres and extends along 21 miles of the
river below the Dow Chemical Co. plant in Midland. EPA's floodplain cleanup will
protect all people who live, work and play along the Tittabawassee
River. Not all areas in the floodplain will need a cleanup. Because
floodplain land is used in different ways, EPA’s plan uses a combination of
steps. In homeowners' yards that are maintained for typical backyard uses, if
tests show a contamination level greater than 250 parts of dioxin in a trillion
parts of soil – or ppt – soil will be dug up and hauled away. Soil will be
replaced and grasses and plants restored. For other areas such as farms, parks,
commercial properties and natural areas, if tests show a contamination level
greater than 2,000 ppt, soil will either be dug up and hauled away or covered
with clean soil. EPA will work with each property owner on the right approach
and after cleanup, these areas will be replanted.
EPA’s Involvement at the Site
Past waste disposal practices, fugitive emissions and incineration at the Midland Plant have resulted in on and off-site contamination that settled in some sediment and built up in some riverbanks. Off-site contamination extends over 50 miles downstream through the Tittabawassee and Saginaw Rivers and into Saginaw Bay.
During cleanup, a site can be divided into a number of distinct areas depending on its complexity. These areas, called operable units (OUs), may address geographic areas, specific problems, or areas where a specific action is required. Examples of typical operable units include construction of a groundwater pump and treatment system or construction of a cap over a landfill.