The Michigan Department of Health and Human Services lifted recommendations that the public avoid the Huron River in Oakland and Livingston counties, as state environmental regulators learned the release of carcinogenic hexavalent chromium from a Wixom auto supplier was not as extensive as feared.

State health officials had issued a no-contact recommendation Aug. 2 after hexavalent chromium was released into the Wixom Sewage Treatment Facility from Tribar Manufacturing in Wixom the weekend of July 29. The sewer discharges to the Huron River system. 

The Michigan Department of Environment, Great Lakes and Energy's investigation has found:

Of 146 water samples collected throughout 42 river miles since the release, hexavalent chromium was detected in three samples. Chromium was found in six of 146 samples. Hexavalent chromium is a known carcinogen that can cause a number of adverse health effects through ingestion, skin contact or inhalation.  

Officials have emphasized that there was no immediate threat to drinking water. The closest drinking water intake is in Ann Arbor, nearly 30 miles away. The city has been notified of the release and is also taking steps to monitor incoming water. The state health department and EGLE plan to conduct sampling for total chromium and hexavalent chromium three times a week at multiple locations upstream of the Ann Arbor intake in Barton Pond. Authorities als once a week for potentially health-harming, nonstick, per- and polyfluoroalkyl substances (PFAS).

The location and timing of sampling is designed to assure protection of the drinking water, EGLE officials said. The public can view the water testing results at michigan.gov/EGLETribarResponse.

EGLE on Aug. 9 issued a notice of "egregious" violation of state environmental law to Tribar. In the notice, EGLE officials asked Tribar Manufacturing officials to answer why company data showed an operator, over a weekend when the factory was not in production, overrode alarms 460 times in about three hours on July 29, as a storage tank's contents were released to the Wixom wastewater treatment plant.

Tribar, in a statement, said the employee involved resigned from the company last week when questioned about the release. 

EGLE spokeswoman Jill Greenberg said despite the spill ending up not as dangerous as first thought, the violation notices stand, with responses due from the company later this month.

"While the release of hexavalent chromium into the river system was much less than initially feared, any unauthorized discharge into a waterway is of concern," she said. "EGLE continues its investigation to determine how and why this release occurred and establish a timeline of events."

Contact Keith Matheny: kmatheny@freepress.com.