Chatham-Kent's Director of Public Works, Ryan Brown, announced that combustible gas was released at the Wheatley site on Friday.
The initial flare was followed by a second event later in the evening and the municipality confirmed that the systems, procedures and venting stack worked according to design and there was no danger to public safety.
Chatham-Kent Fire and Emergency Services were also on-site and monitored the air around the perimeter of the evacuation zone to ensure safety.
The municipality said that following the second incident the flare stack was ignited to control the gas and the site was set up for overnight observation. Gas levels lowered and the stack was extinguished at 9 a.m. on Saturday.
"We are pleased that the mitigation equipment/procedures on-site are working exactly as planned and are confident that the current evacuation zone remains secure," Brown said in a release.
Wheatley's evacuation zone was just reduced a little under two weeks ago.