The Michigan Department of Environmental Quality is proposing to change the state's standard for 1,4 dioxane to 7.2 parts per billion.
That's a ten-fold difference from the current standard of 85 parts per billion. 1,4 dioxane is a known carcinogen.
The DEQ missed a December, 2015 deadline for issuing updated standards for 308 chemicals, including 1,4 dioxane.
The agency has issued the new standard for 1,4 dioxane first, likely in response to an increased outcry from Ann Arbor city officials and residents.