Canadians familiar with North America's largest oil pipeline operation, Enbridge Inc., say they are not surprised that the company has spilled oil again.

Greenpeace protesters dressed as oil workers walks past the flow of molasses and water meant to represent an oil spill outside the offices of pipeline and energy company Enbridge in Vancouver, British Columbia July 28, 2010. The Greenpeace group were protesting the pipeline burst on the Kalamazoo River in the United States and the future plans to build a new pipeline in British Columbia. REUTERS/Andy Clark Enbridge, based in Calgary, last week reported that an estimated 819,000 gallons of crude oil had leaked from its 41-year-old pipeline into Talmadge Creek and the Kalamazoo River. The Line 6B pipe carries crude from Indiana to Ontario.

As lawsuits begin to emerge, so has information about the company's history of failed pipelines.

Patrick Daniel, Enbridge president and chief executive officer, said Saturday there has "never" been a leak of this "consequence" in the company's history.

The spill is the largest for Enbridge in the United States by volume and the company has a history of spills throughout Canada and the U.S., according to the Polaris Institute, an Ottawa-based advocacy group for democratic social change.

The institute reports that Enbridge was responsible for 610 spills that released more than 5.5 million gallons of oil between 1999 and 2008. The total is about half of what spilled from the Exxon Valdez after it ran aground in the Prince William Sound in Alaska in 1989.

"The Michigan spill should be wake-up call for those who would allow Enbridge to build two 1,170 kilometer pipelines from the Alberta tar sands to the (British Columbia) coast," the institute said on its website Wednesday. "The question is not 'if' a catastrophic spill will occur on this route, but 'when'."

The institute is referring to plans Enbridge has to ship super tankers carrying bitumen, an asphalt-like substance, from the Alberta tar sands through the coast of British Columbia, including the fragile Great Bear Rainforest. The Canadian federal government also is reviewing company plans to build twin 715-mile underground pipes capable of transporting 525,000 barrels daily across Alberta and British Columbia.

Canadian Union of Public Employees on Thursday issued a statement of opposition to the plan spurred by the Kalamazoo River and Gulf of Mexico disasters. It joined First Nations, representing ethnic Canadian Aboriginal groups, and environmental organizations in opposing the Enbridge Northern Gateway plan."As we've seen in Michigan and the Gulf coast, any kind of oil spill on our coast would have a tremendous impact on the natural environment and would impact wildlife, including salmon and the Kermode bear which is unique to the Great Bear Rainforest," said Leanne Louie, CUPE British Columbia diversity vice-president for aboriginal workers, in a statement. "With the BP oil spill, the damage is irreversible. We can't let that happen here."

Greenpeace Canada on Wednesday occupied an Enbridge office in Vancouver demanding that Enbridge withdraw its Northern Gateway application.

With oil collected from the Gulf oil spill, activists wrote "B C Next?" on its glass office doors, according to its website. They set up a mock pipeline outside the office to simulate an oil spill in British Columbia's natural habitats.

Enbridge stock prices have fallen $1.92 between opening on July 26 at $50.56 per share -- before the leak was announced -- and closing Friday at $48.64 per share on the New York Stock Exchange, despite a positive second quarter report Wednesday.

"While we're very proud of our second quarter financial performance, unfortunately, we are reporting those results at the same time as members of our team are in Michigan doing their utmost to respond to the leak," Daniel said in a statement, noting the leak has been stopped and clean-up operations are in full swing.

Despite the Kalamazoo spill being one of Enbridge's largest, financial analysts have said it appears the oil spill will not have a significant effect on the company's bottom line. They are encouraged by the fact that the company is insured against these types of disasters and that it has plans to expand.

The company reported Wednesday its U.S. affiliate, Houston-based Enbridge Energy Partners, plans to buy the natural gas pipeline and processing company Elk City Gathering and Processing System for $682 million. Its 800 miles of pipe extend from Oklahoma to Texas.

Analysts say, however, that because of the protests and recent oil spill, the company will have a harder time selling its Enbrige Northern Gateway expansion plan in British Columbia.