The regulator says 27,000 litres of contaminated water were released underground on Jan. 3 at the company’s troubled Primrose field.
Darin Barter, a spokesman for the regulator, says the leak has been stopped.
He says none of the water reached the surface or contaminated underground aquifers.
Barter says the leak was caused by a well failure — unlike a leak last summer that also remains under investigation.
In the previous leak, more than a million litres of bitumen seeped to the surface.
The company says that leak was also due to well failure.
Barter says the regulator doesn’t yet accept that explanation.