Local news media reported this week that US Steel’s Portage, Indiana mill spilled 56.7 pounds of chromium into a tributary of Lake Michigan on Oct. 25, although local residents and regional environmental groups were not informed at the time.
US Steel said in a statement to media that the chromium was released after a “wastewater treatment system malfunction.”
The company reportedly discovered the malfunction on Oct. 26 and notified the Indiana Department of Environmental Management (IDEM) on Oct. 27. According to the Chicago Tribune, a US Steel official sent a request to the IDEM Office of Water Quality on Oct. 31, asking to “be afforded confidential treatment of the incident under all applicable statutes.”
U.S. Steel spokesperson Meghan Cox told media that the confidentiality request was made “due to business sensitive material,” although she did not offer specifics. The request has since been waived.
Officials with Indiana Dunes National Lakeshores and Indiana American Water did not learn of the spill until earlier this week, and an EPA spokeswoman said Indiana state officials didn’t notify the agency until Nov. 14.
US Steel said the spill “did not pose any danger to water supply or human health” and that it is working with state officials to ensure there is no “environmental impact” from the spill. Chromium, which is used to make steel, has been known to cause cancer.
The recent spill marks the second from the same facility this year; over 300 pounds of hexavalent chromium was dumped into a small waterway near Lake Michigan in April.