Imperial Oil says the tailings pond overflow at Kearl Lake was due to a combination of equipment and process failure.Nicholas Vardy/Supplied
After almost a year of tainted water from a tailings pond leaking into the environment around the Kearl oil sands project, a lake at the northeastern edge of the northern Alberta site now contains levels of toxins that exceed government guidelines.
The most recent round of water testing, commissioned by the Alberta Energy Regulator (AER), confirmed the finding, which was announced Wednesday evening.
The small lake, which feeds into a tributary of the Firebag River, also contains naphthenic acids, which are formed from the breakdown of petrochemicals and are typically found in oil sands tailings.
The tailings leak at Kearl has been going on since last May, and one of the project’s owners, Imperial Oil Resources Ltd. IMO-T, still doesn’t know how much tainted water has escaped since the leak was first detected.
Later this month, chief executive Brad Corson will fly to Ottawa to testify before the House of Commons environment committee to explain how Imperial has handled the problem. Laurie Pushor, the CEO of the AER, will testify before the committee on April 24.
The federal government, local Indigenous communities and the public at large were not informed of the seepage from Kearl until this February, after a separate incident spilled 5.3 million litres of industrial wastewater laced with pollutants from a drainage pond into the environment.
A combination of equipment problems and process failures caused that spill, Imperial said in a statement posted to its website Wednesday evening.
According to its investigation, measurement equipment was not accurately reading the level of the drainage pond. That meant a pump that is normally automatic was instead in manual mode and failed to lower the level of the water.
The pond in question collects water from surface drainage systems and Kearl’s seepage interception system, as well as silt and sediment from the surrounding area, which accumulate over time. Imperial said it was this gradual buildup of sediment that affected the accurate measurement of the pond level.
Human eyes also monitor Kearl ponds, but Imperial said “routine operator inspection rounds did not initially detect the high pond level due to winter conditions and low visibility.”
The spill occurred on Jan. 31, the company said, and was eventually noticed on Feb. 4, when it was reported to the AER.
“This incident should not have happened. We have identified the issues and are taking actions to prevent potential reoccurrence,” Simon Younger, Imperial’s senior vice-president of upstream operations, said in a statement.
The company said cleanup work from the spill is complete.
Meanwhile, independent sampling results released by the AER late Wednesday have confirmed the presence of hydrocarbons and naphthenic acids in the lake just beside the Kearl site.
The water samples were taken from multiple locations on April 6 and reported to the AER on April 10. The regulator said in a statement that the toxins “are potential indicators of industrial wastewater,” adding that it is communicating directly with Indigenous communities, stakeholders and government authorities about the results.
Low levels of naphthenic acids were detected at two locations close to the continuing leak and at a new location near the outlet of the lake, which is home to fish and other aquatic life. The AER noted that no guidelines exist for naphthenic acids, which occur naturally in the region.
The regulator said it has directed Imperial to take additional measures to reduce and restrict the outflow of water from the lake. Both the AER and Imperial say no adverse effects on fish or wildlife have been observed.
The provincial government is planning to ramp up monitoring frequency during the spring melt near the Kearl site and along the Firebag River.