Windsor firefighters spent six hours at the Chrysler plant early Wednesday, flushing out the source of a strong odour of gas come from the sewers.
Fire prevention officer John Lee says the problem was traced to the paint plant, where runoff waste became clogged in the sewers.
A hazardous materials crew flushed more than 470,000 litres of water down the sewers to reduce the gas levels, Lee said.
He said recent heavy rainfall forced the gasoline odours to rise. A vacuum truck was to be brought in to clean up the runoff. Minivan production wasn't interrupted and the gas did not pose a threat to safety, Lee said.