Chicago argues U.S Steel’s plant in Portage violated the federal clean water act. The factory says 350 pounds of chromium spilled into a runoff that feeds into Lake Michigan. Chromium is a chemical used for welding and is considered a carcinogen.

In April of 2017, a pipe broke and started spilling chemicals into the water 100 yards away from Lake Michigan. As a result, the nearby Indiana Dunes National Park was closed.

The Indiana Department of Environmental Management reports U.S Steel failed to notify any downstream users of the waters contaminated by the spill

Another spill happened again in October 2017. Chicago claims U.S. Steel failed to properly report the second spill and the amount discharged into the water.

The lawsuit asks for injunctive relief and civil penalties against U.S Steel.

You can find the full release from the Chicago Mayor Rahm Emanuel here.