A worker lifts oil-covered debris from the Kalamazoo River on Tuesday. (John Grap/Battle Creek Inquirer/Associated Press)

As Calgary-based Enbridge Inc. works to clean up a major oil spill from one of its aging pipelines in Michigan, Alberta officials say the province's network is safe.

About 3.7 million litres of oil leaked into the Kalamazoo River on Monday near Battle Creek, Mich., from a pipeline leading to Sarnia, Ont.

Crews are trying to prevent the spill from reaching Lake Michigan, about 125 kilometres away.

While the Michigan pipeline was built in the late 1960s, most of the lines in Alberta are newer, said Energy Resources Conservation Board spokesman Bob Curran.

"Although the pipeline system has grown exponentially over the last decade or so, the safety record has improved dramatically over that same period of time," he said.

But the Pembina Institute, an environmental group, says Albertans should be worried about the safety of the approximately 400,000 kilometres of pipelines criss-crossing the province.

'It's unlikely that there would be many segments in Alberta that are decades old.'— Bob Curran, Energy Resources Conservation Board

"What concerns me is that we could be seeing more and more pipeline failures in the next while because the pipeline infrastructure is aging," said the institute's Karen Campbell.

Older pipelines are regularly inspected by the Energy Resources Conservation Board, and the companies that own them routinely replace corroded segments, Curran said.

"It's unlikely that there would be many segments in Alberta that are decades old, unless they're on the types of lines where they're not really prone to corrosion or leaks. Or they're carrying substances that wouldn't cause a lot of problems if there was a leak."

For every 1,000 kilometres of pipeline, about two failures happen every year, including damaged lines or leaks. There are about 800 failures a year, the regulator said.

2008 oil leak into Alberta waterways

In June 2008, heavy river flows lifted a section of a pipeline and caused a leak of as much as 32,000 litres of oil into the Red Deer River and Gleniffer Lake north of Calgary.

The popular recreational lake was closed for about 10 days and led to restrictions on drinking water in the area. The pipeline, owned by Pembina Pipelines, was subsequently repaired to the energy board's satisfaction.

Board officials will review the Michigan spill once the cause has been made public, Curran said.

Patrick Daniel, Enbridge's CEO, has vowed that "anything and everything" affected by the oil will be cleaned. The U.S. Environmental Protection Agency has taken charge at the spill site, saying it will work with Enbridge to clean up and contain the oil.