An Imperial Oil pipeline spilled 843,000 litres of bitumen emulsion northwest of Cold Lake, Alta., last week.

In a statement to CBC News, Imperial Oil spokesperson Lisa Schmidt said teams responded immediately. The release, which occurred April 9, has been stopped and contained, and cleanup and remediation are underway.

“We are sorry this incident occurred," Schmidt wrote.

An Alberta Energy Regulator (AER) spokesperson confirmed the agency sent inspectors to the site of the spill — about 30 kilometres northwest of Cold Lake, a city near the Alberta-Saskatchewan border.

Although, Kevin Timoney, ecologist with Treeline Ecological Research, has studied thousands of spills and believes wildlife and waterbodies could be affected.

“There are always impacts and I know that, in the vast majority of cases, those impacts are not adequately reported,” Timoney said.