(Recasts with pipeline being shut indefinitely, Husky apology, details on wildlife impact, investigation)
By Rod Nickel and Nia Williams
July 25 (Reuters) - Husky Energy Inc has indefinitely closed a pipeline that leaked oil into a major Canadian river, a company official said on Monday, as the spill forced a second city to stop drawing drinking water.
Heavy oil and diluent leaked from a 19-year-old pipeline in Husky's Saskatchewan Gathering System on Thursday, flowing into the North Saskatchewan River, which supplies water to several communities in the western Canadian province.
The northern part of the system will remain down until Husky has "dealt with the crisis at hand," said Husky executive Al Pate, adding the company was "deeply sorry."
Canada's federal environment department is investigating the incident, said spokeswoman Lo Cheng.
The oil reached Prince Albert, population 35,000, hours earlier than expected on Monday, widening the impact and cost of the spill. Workers there raced to stretch a 30-kilometre (19-mile) hose to draw drinking water from another source.
A sheen was visible on the river in the morning, spurring the city to shut its water treatment plant intake, said city manager Jim Toye. It has two days worth of stored water before it must find another source.
"We thought we had more time," Toye said in an interview. "We (will) really hit the wall after two days."
Less than half of the 1,572 leaked barrels of oil had been recovered as of Monday, Saskatchewan environment official Wes Kotyk said.
Upstream of Prince Albert, the city of North Battleford stopped drawing drinking water from the river last week.
Once Prince Albert's stored water is exhausted, it hopes to use rainfall collected in a retention pond, buying itself four more days, Toye said. After that it would rely on water from a 12-inch (30 centimeter) diameter hose to the South Saskatchewan River, running along a highway.
Farms outside of Prince Albert that rely on city water have had supplies cut off.
"It's a real nuisance. And for some it could become a real health issue," said farmer Larry Fladager. "Can't drink, can't shower, can't wash your clothes."
Prince Albert's water plan covers two months, but Toye said its supply may be strained longer.
The cost will run into millions of dollars and the city is "very disappointed" by limited communication and assistance from Husky, Toye said.
Pate said Husky is in daily contact with communities and would cover unspecified costs.
He declined to say how the spill has affected production. (Reporting by Rod Nickel in Winnipeg, Manitoba, with additional reporting by Nia Williams in Calgary; Editing by Jeffrey Hodgson)