Municipal officials reported a hydrogen sulphide gas emission in Wheatley on Sunday, but are crediting safety measures for working as intended to mitigate the situation.
Contractors drilling a monitoring well near the APEC 2 site hit a pocket of the toxic gas 85 feet below the surface at 11:05 am, according to a release.
Safety measures “worked as designed,” officials added, and the site was evacuated. There were no injuries. A loud hissing noise accompanied the emission, which lasted until 11:20 am
Thomas Kelly, Chatham-Kent’s general manager of infrastructure and engineering, stated in the release a mobile vent stack system at the site of the well drilling was successfully deployed, allowing the gas to vent to atmosphere without an issue.
Drilling was stopped and the crew moved out of the hot zone after connecting the well to the prepared vent system to dissipate the gas. Work has since resumed, officials added.
Fire and emergency service Chief Chris Case said a safety plan had been rehearsed for such an event.
“As part of our response plan, we have firefighters 24/7 on site, they are supported by the Wheatley firefighters who were called,” he said. “We do not use lights/sirens so as not to cause stress to the local community.”
Additional chief officers and medics were deployed on standby as the engineering team continued the work.
Hazmat personnel and technicians ensured the area was safe while fire crews and other technicians began mobile monitoring in the vicinity.
“We were advised that the event had concluded and that apart from the detectors close to the drill site no gas had traveled creating a risk to the community,” Case added. “All response teams were stood down around midday and the engineers have returned to work. I am pleased to advise that the plans, which are practiced and drilled regularly, worked.”
He said the incident shows the unpredictable and potentially dangerous conditions that can occur and supports the cautious approach taken by authorities to only allow access to properties when work is not underway.
Kelly said the APEC 2 monitoring well is the first of two monitoring wells to be installed.
One well will reside inside the investigation area and the second just outside the evacuation zone, the release added. These wells will allow investigators to obtain groundwater and gas samples in support of the chemical modeling work.