Dow’s facilities in Midland, Michigan, where the company is headquartered along the Tittabawassee River, produced chlorine-based products from the early 1900s. The company released dioxins, chemicals which can cause reproductive damage and cancer in the river.
Pollution has accumulated in sediments in and along the river and in its flood plains, extending 50 miles downstream across the Saginaw River and Saginaw Bay.
The US Environmental Protection Agency (EPA) superfund program has overseen Dow’s site cleanup since 2012, and the final part of the project is expected to be completed in 2021.
In the three-mile section of contamination closest to the Midland plant, Dow removed sediment and placed a cap on the other sediment.
Former EPA officials warned that the cleanup project was probably not designed to protect against a flood event of this magnitude and said high-speed water could damage the cap and release sediment contaminated in the river.
“They would certainly have considered high water flows. I don’t think they would have considered something as blatant as a dam failure, “said Bill Muno, former EPA director for the region.
The flood could also potentially break a containment system built for contaminated soil, depending on how it was built, said Muno.
Toxic soil could spread floodwater to the surrounding community and to residents’ yards.
The Dow facility could also be at risk of flooding. Downtown Midland may soon have up to 9 feet of water, authorities have warned.
Kyle Bandlow, a spokesperson for Dow, told the New York Times that the floodwaters had reached the outer limits of the facility and were entering ponds designed to hold water runoff from the site.
Dow did not immediately respond to a request for comment on the risk of flooding the superfund site.
The EPA said that at the time, “Dow did not report any chemical releases to the river.”
“The EPA’s clean-up plan for this site requires Dow to perform a post-flood assessment to determine if there is recontamination or if the built-in clean-up remedies have been damaged,” said the federal agency.
“The EPA assessment following a major flood in 2017 determined that the impact on the superfund site was minimal and Dow made necessary and minor repairs as needed. “