PORTAGE, Ind. (AP) – Two environmental groups are suing a steelmaker for allegedly violating the Clean Water Act at its northwestern Indiana facility more than 100 times in the past five years, including an August spill that killed over 3,000 fish.

The Environmental Law and Policy Center and Hoosier Environmental Council filed the lawsuit Wednesday after previously alerting ArcelorMittal of their plans to sue.

The groups allege ArcelorMittal breached its Clean Water Act permit after releasing impermissible levels of cyanide and ammonia in August.

The spill killed fish, forced nearby beaches to close and kept visitors away from the newly designated Indiana Dunes National Lakeshore.