Dan Martin / news@WHMI.com

Michigan Governor Gretchen Whitmer paved the way this week for federal Superfund status for the Gelman Sciences contaminated groundwater plume in Ann Arbor.

Governor Whitmer sent a letter concurring with the transfer to the U.S. EPA. An industrial solvent, called 1-4 dioxane, is spreading beneath western Ann Arbor and Scio Township.

It comes from decades of pollution from Gelman Sciences, a chemical company. The plume has forced the city of Ann Arbor to close one of its drinking water wells, and a number of people with private wells had to be connected to the city's drinking water system due to the contamination.

Local officials and advocates have been asking that the site be included on the national priorities list. The governor's letter to the EPA says placing the site on the NPL is the most viable way to address the issue.

EGLE Director Phil Roos said the agency has worked closely with EPA on managing the site and will ensure that the transition to Superfund status is seamless and effective.

“We welcome all available resources to address what is a very complex site of legacy contamination,” said Roos, who lives in Ann Arbor. “We’ve listened to the community and concur with their wishes to ask the EPA to make this a priority site. We’ll continue to work with the community and EPA to ensure residents are protected.”

The federal environmental agency’s policy is to secure agreement from states before proposing a site to the list, according to the EPA’s most recent update on the Gelman plume.

Still, a decades-long legal battle over the pollution continues to play out in state courts, with lawyers representing Washtenaw County and Gelman Sciences appearing in late November for the latest round of arguments in the 35-year-old case over the plume.