Hydrogen sulphide gas has again been detected at the site of an explosion in downtown Wheatley, Ont., according to municipal officials, six weeks after an explosion injured 20 people and has displaced many residents and business owners.
The toxic, combustible gas was picked up by monitoring equipment at 4 a.m. ET Friday, the Municipality of Chatham-Kent said in a news release.
The municipality said that as of Friday morning, the gas is still being detected.
"We believe gas is building up underground in some type of cavern and then it is relieving itself, and that's the pressure relief we are seeing," said Chatham-Kent general manager of infrastructure and engineering, Thomas Kelly, in a media briefing Friday.
Kelly explained this is the fourth time a "relief" of the underground gas has happened since June, including when an explosion occurred in August.
"Our goal is to find out where that's occurring, and that's the work we did this week."
This week, underground surveys were conducted searching for cavities where gas could be building up.
According to officials, gas detection equipment is being used to monitor the evacuation zone and surrounding perimeter. No gas has been detected outside of that zone.
No additional evacuations have been ordered, but the public will be notified if the situation changes.
Various emergency officials are on the scene, including firefighters and the provincial hazmat team. Samples of the gas have been sent to the University of Windsor for analysis.
Kelly said the university's findings will be extremely helpful when it comes to locating the source of the gas leak underground.
The Aug. 26 explosion destroyed two buildings and has displaced more than 100. They remain out of their homes and businesses.
A hydrogen sulphide leak is believed to be the cause of the blast, but officials have not yet located the source.
Those displaced were told they could be out of their homes for up to six months.
On Friday, officials asked the community to be patient.
Kelly said he understands residents and business owners need to access their properties, but Friday's gas detection is an example of why the site is not secure enough to do so.
He said the municipality is working hard to find a safe way to accommodate the community.