EPA: Toxic solvent plume in Ann Arbor eligible to be added to roster of most polluted sites

The U.S. Environmental Protection Agency has determined a plume of a toxic solvent moving under Ann Arbor is eligible for inclusion on the National Priorities List, a federal roster of the nation's most concerning polluted sites, state environmental officials and U.S. Rep. Debbie Dingell announced Friday.

Placement on the list would mean the plume, known as the Gelman Sciences plume, becomes part of the EPA's Superfund program. If the site is listed, the agency will work on a feasibility study to determine how it will remedy the pollution.

The Michigan Department of Environment, Great Lakes, and Energy "is committed to working closely with USEPA and affected communities to ensure a smooth transition to federal oversight, and that residents are protected throughout the process," said EGLE director Phil Roos. "We support the communities' desire to bring federal resources to bear on this longstanding issue, and will support them and EPA going forward."

The EPA investigated the plume of 1,4 dioxane last year to determine whether it was a fit for the federal program after local government leaders pushed for the agency to step in, contending it could use its regulatory power to require Gelman to take stronger action to clean up the pollution.

The agency determined levels of the compound are three times higher than typical levels found in the area and said it is eligible for inclusion on the Superfund program's National Priorities List.

"We're not finished yet ― we won't stop until we have the final rule and the plan in place — but this is a very important step," Dingell said of Friday's announcement that the Gelman plume is eligible for the EPA Superfund program. "I'm committed to seeing this through and finally ending this nightmare for all the residents who have been dealing with this for too long."

1, 4 dioxane is a solvent that can cause liver and kidney damage through long-term exposure. It is probably cancer-causing, according to the EPA.

The plume was created by Gelman Sciences Inc., which used 1,4 dioxane to manufacture medical filters from 1966 through 1986. The company dumped wastewater into unlined lagoons, a deep injection well and disposed of it through spray irrigation.

The waste has spread underground from the manufacturing site on South Wagner Road through Ann Arbor Township, Scio Townships and western Ann Arbor. The plume is now roughly four miles long and one mile wide, according to EGLE.

The company monitors the plume and treats some of it, but the pollution continues to move and affect a growing swath of Washtenaw County.

Communities have undertaken the monitoring work that helps determine the size of the plume. Well water testing costs Scio Township roughly $50,000 per year, Trustee Kathy Knol told The Detroit News last year. About 200 Scio Township homes have been annexed into Ann Arbor so they could access the city's drinking water system.

Ann Arbor installed two monitoring wells last year at a cost of approximately $400,000 to determine how close the plume is to its drinking water intake.

ckthompson@detroitnews.com