Some homes have been evacuated and a state of emergency has been declared due to a gas leak in downtown Wheatley.
People are being asked to avoid the area.
Officials say the cause of the leak is under investigation. The situation doesn't involve a natural gas line but rather naturally occurring hydrogen sulfide gas that is coming up from the ground.
Crews responded to a report of a gas leak at a restaurant at 16 Erie Street North before 2:30 p.m. on Wednesday.
A property owner had detected the smell of rotten eggs in their building and saw something bubbling up from the drain in their basement, according to Chatham-Kent's chief administrative officer Don Shropshire.
"The gas is both flammable and toxic. That warranted establishing a safety zone around the site," he told reporters at a news conference Thursday.
A hazmat team from Windsor was brought to the scene to assist on Wednesday evening.
About 20 electricity customers have had their service shut off, including 13 residential customers.
Overall, Shropshire said he believed 16 homes have been evacuated, some to emergency shelter and others staying with family and friends.
Chatham-Kent fire chief Chris Case said the response is still in the emergency phase but based on previous experiences, it could take weeks or months to stop the gas from leaking. The gas is coming up from two or three different places.
The region has many hydrogen sulfide wells and some deposits that are untapped, officials explained.
Case said the release of the gas suggests it could be coming from a capped well.
"We're currently working with agencies to try to determine the source whilst making the scene safe," he said.
Dr. David Colby, medical officer of health for Chatham-Kent, said the gas is toxic but exposure is easy to detect at low concentrations.
"You smell it long before it gets to dangerous levels. And that is a very good thing," he said.