"Three Lake Michigan beaches remain closed after a northwest Indiana steel mill dumped toxic chemicals into a tributary earlier this week, an incident that was not reported to the public until hundreds of dead fish began floating past boaters.
Luxembourg-based ArcelorMittal notified Indiana officials on Monday that a plume of cyanide and ammonia from its Burns Harbor steel mill had spilled into a branch of the Little Calumet River. But the mayor of Portage, a lakefront city west of the plant, said the state’s environmental agency did not alert local officials or citizens until Thursday.
As a precaution, the National Park Service closed the Portage Lakefront and Riverwalk beach area at Indiana Dunes National Park. The neighboring community of Ogden Dunes also closed its beach and restricted its Lake Michigan water intake."