Husky Oil said a leak from one of its pipelines spilled about 200,000 litres of heavy oil mixed with a thinning chemical into the North Saskatchewan River near Lloydminster, Sask., Thursday.

The company said it shut the pipelines, part of its Saskatchewan gathering system, which halted the release.

The line was moving heavy oil with a product called diluent, which helps the oil flow. The spill into the river was noticed as a sheen on the water Thursday morning. It entered the river about 30 kilometres east of Lloydminster.

According to the company, the total volume was "estimated at 200 to 250 cubic metres." A cubic metre is equivalent to 1,000 litres.

The nearest town to the leak is Maidstone, Sask.,which is approximately 220 kilometres northwest of Saskatoon.

The provincial government confirmed the leak and noted Husky activated an emergency response team and berms were being used to contain the spill.

Another berm was being set up further downstream near Paynton, Sask.

Husky said the company is working closely with authorities and area municipalities.

We will be watching the water. - North Battleford, Sask., official Tammy MacCormack

Spokesman Mel Duvall said in an email that the oil was in a line that runs from the company's heavy oil operations to its processing facilities in Lloydminster.

"A sheen was observed on the North Saskatchewan River," Duvall said. "Husky immediately deployed spill response equipment and crews to commence clean up, recovery and water sampling."

The province said an environmental protection officer had been dispatched to the site. It also said Husky, with co-operation from the province, was notifying river users downstream of the spill.

Water sources being monitored

In North Battleford, Sask., which draws its water supply from the North Saskatchewan River downstream from the spill, city officials said they had been informed and were taking precautions.

"The spill might not reach the city as cleaning efforts are underway, including the use of river booms near Paynton that will skim for materials," Susanne Abe, a communications official for the city, said in a statement. "In case the oil spill reaches North Battleford, the city has taken precautionary measures."

Tammy MacCormack, the city's environment manager, said it was unknown how long it would take for the flow to reach North Battleford. But water samples were being taken, she said, and supply intakes would be shut if the oil spill reached the city.

"Our plan is to be shut down when it goes by," said MacCormack. "We will be watching the water."

According to the city, the oil could reach North Battleford by Friday morning.

"The oil spill does not pose a health risk to consumers," Abe said in her statement.

She added that in the event the water treatment system is shut down, the city would turn to an alternate facility that uses ground water for its supply.

In that case, the city would ask residents to reduce water use.

Duvall said the company was "working closely" with a number of regulatory agencies and government officials on the matter and added more details would be provided as their investigation into the leak proceeds.