Imperial Oil penalized $120K for substantial 2023 wastewater spill at Kearl Site

An image of the industrial wastewater leak at Imperial Oil's Kearl Mine site north of Fort McMurray. (Source: Nick Vardy)

Imperial Oil has been penalized $120,000 for a wastewater spill at its Kearl oilsands mine near Fort McMurray, Alta.

Alberta’s energy regulator laid nine charges against the company last year in connection to the 2023 spill, which saw about 5.2 million litres of wastewater overflow from a drainage pond.

An agreed statement of facts shared Thursday by the regulator says the company agreed to plead guilty last month to one of the offences: releasing substances from the mine to the surrounding watershed without approval.

The other charges were withdrawn. They included failing to report the spill as soon as it was known and releasing a substance that “caused or may have caused a significant adverse effect.”

The court document says the pond contained wastewater from bitumen processing, precipitation and seepage from other ponds at the mine.

It says the pond had a digital measurement system to sound alarms and activate pumps if the capacity limit was reached.

However, sensors were designed so alarms would be triggered even if the pond wasn’t near capacity, which led workers to believe the sensors weren’t reliable indicators.

As a result, workers routinely monitored the pond’s capacity themselves and manually turned on pumps to lower levels if necessary.

The court document says that on the morning of Jan. 28, 2023, a worker turned on the pumps to lower the pond. An alarm sounded 21 minutes after the pumps were shut off, but no action was taken.

Staff noticed the spill a week later and reported it to the regulator.

The document says wastewater didn’t reach another body of water, as it froze just outside of the company’s lease area. Affected snow, ice and soil were removed in the weeks that followed.

Imperial Oil spent about $2 million remediating the area, says the document, and soil quality tests show normal amounts of metals and petroleum hydrocarbons.

A court order issued Thursday says most of the $120,000 penalty is to fund a still-to-be-determined project to benefit Alberta’s public lands, Indigenous territories, wetlands or surrounding ecosystems.

A spokesperson for Imperial Oil said in a statement that it regrets the spill and has made equipment and training changes.

“No water from this overflow entered any rivers and there continues to be no indication of adverse impacts to local wildlife,” said Lisa Schmidt.

“We continue to share monitoring data with local Indigenous communities and provide site tours of the area.”

Imperial Oil was previously fined $50,000 for a wastewater spill at the same mine in 2022.

That spill, which involved wastewater containing tailings, led to outrage from First Nations in the area, as its full scope wasn’t disclosed for nine months — when the 2023 spill was announced.

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This report by The Canadian Press was first published June 11, 2026.