Washington — U.S. Rep. Debbie Dingell, D-Ann Arbor, asked the CEOs of Ford Motor Co., General Motors Co., Stellantis NV and Toyota Motor Corp. in a letter Thursday to stop using a cancer-causing chemical in their supply chains.
In late July, Tribar Manufacturing in Wixom discharged liquid containing hexavalent chromium, a carcinogenic chemical, into the sanitary sewer system near the plant leading into the Huron River. Tribar is an automotive plating company that supplies the four automakers and others, Dingell said.
“While most of the contamination was captured before it could make its way into the environment this could have been a major environmental disaster,” she wrote. “Strong, respectable American companies should hold their suppliers to the same caliber as their own.”
She added that the Tribar incident has reinforced the need for the auto industry to remove the substance from its supply chains and to review the environmental actions of all its suppliers.
Ford, GM, Stellantis and Toyota did not immediately respond to requests for comment.
The Tribar plant was allowed to resume sending its wastewater to the Wixom Wastewater Treatment Plant in early September, more than a month after the city sent a cease and desist order to the company due to the dump.
The Michigan Department of Environment, Great Lakes and Energy found in an investigation that a Tribar employee overrode waste treatment alarms 460 times and that the company failed to notify the state immediately after learning of the pollution.
The state also found that most of the chemical that was released into the sewer system was either contained or broke down into a less toxic substance before it was discharged, resulting in less pollution than officials initially expected. EGLE determined Tribar Manufacturing released 3,892 pounds of hexavalent chromium into the sewer system on July 29.
The company has also been responsible for releasing perfluoroalkyl and polyfluoroalkyl substances (PFAS) into the Huron River. Hexavalent chromium usually requires the use of PFAS mist suppressants, Dingell said.
The State of Michigan is continuing to monitor water quality near the plant.
Staff Writer Carol Thompson contributed to this report.
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