Leaked oil is sticking to debris pulled from Gleniffer Lake. (Denis Genereux/CBC)

Crews are trying to clean up a spill of crude oil that's left an oily sheen on a popular central Alberta lake.

Between 75 and 125 barrels of oil leaked from the pipeline that runs under the Red Deer River near Sundre, 130 kilometres northwest of Calgary. The pipeline is licensed to Pembina Pipelines, the Alberta Energy Resources Conservation Board said Monday.

The agency said an aerial search of the river detected an oil sheen on Gleniffer Lake, about 33 kilometres downstream from the leak. Crews are using booms to try to capture the oil on the lake.

Workers at Pembina Pipelines realized the line was losing pressure shortly after 9 p.m. Sunday, said company official Brad Smith. He said he didn't know how the leak happened or how much of the oil has been recovered.

Crews work on recovering oil from the lake on Monday. (Denis Genereux/CBC)

An ERCB investigation is underway.

"We haven't detected any oil on the Red Deer River," said ERCB spokesman Davis Sheremata. "Due to heavy rains, the water in the river is moving really fast."

Gleniffer Lake, home of two resorts, a campground and hundreds of cottages, is a popular spot for recreational water sports.

"We certainly had some concerns," said Bill Gourley of Carefree Resort, which has about 100 guests this week and is near where the river flows into the lake. "We can see a little skim of a sheen on the water."

The Gleniffer Lake Resort said it has between 400 and 500 guests this week, a number that swells to up to 1,500 on weekends.

The lake is a popular spot for recreational water sports. (CBC)

Cheryl Robb, spokeswoman for Alberta Environment, said crews are taking safety precautions to protect the people who use the lake.

"There's two drinking water intakes on the lake that have been shut, so the drinking water that's been in the treated reservoirs is still available to use but nothing's coming off the lake now," she said. "Downstream, the users in Innisfail and Red Deer — because the Red Deer River flows through — they're not being affected right now, but they have been notified."

Smith said the pipeline, built in 1959, was last inspected in January.

Rachel Notley, Alberta's NDP environment critic, slammed the provincial government for a shortage of pipeline inspectors.

"Alberta has 392,000 kilometres of pipeline and only 85 inspectors," Notley said in a news release Monday. "That means each inspector is in charge of a stretch of pipe that could reach from Edmonton to Florida."

In August 2000, a pipeline owned by Pembina Pipelines ruptured in B.C., spilling about 6,200 barrels of light crude oil into the Pine River, about 110 kilometres upstream of the community of Chetwynd. The Pine River flows into Alberta's Peace River.

The company was charged by Environment Canada and was eventually fined $5,000 and ordered to pay $198,000 to repair damaged fish habitat.

With files from the Canadian Press