Cenovus Energy is tackling a release from a heavy oil site north of Paynton. The thermal plant is about 80 km southeast of Lloydminster.
A visible plume was reported, but the company said it was mostly water vapour and dirt.
The company statement adds that it is updating nearby communities and monitoring air quality. Also, Cenovus is making provisions so that farmers can get into their fields.
Also, it was injecting water into the well to bring it under control. This is causing increased odour in the area.
Cenovus put in berms at the Rush Lake 2 Facility on Monday afternoon for containment.
The plant is described as a Steam-assisted gravity drainage operation. This means it uses steam, which is injected underground to make the oil easier to extract.