"They knew there was seepage to groundwater," said Mandy Olsgard, an environmental toxicologist who has consulted for area First Nations.Imperial said in a statement that seepage was anticipated in Kearl's original design. Spokeswoman Lisa Schmidt said the company has kept both the regulator and area communities informed.
"During this period, there were no signs that indicated the system was not functioning according to its intended design." Substances found at concentrations above desired limits included naphthenic acids, dissolved solids and sulphates — a common proxy for hydrocarbon residue. Oilsands tailings are considered toxic to fish and other wildlife.
"These original interception pumping wells were first activated in early 2021 in response to the detection of process affected water above control objectives, in accordance with approved operating procedures," Schmidt said. That sampling station is south of the Kearl lease. The releases that trigged the protection order were on the north side.Stewart said Imperial has increased its monitoring frequency and is working to understand the extent of the release.