By Ken Paulman, Midwest Energy News

Enbridge, the company responsible for a pipeline leak that spilled more than 800,000 gallons of oil into a Michigan river this week, has a history of breaches on its network of oil and gas pipelines.

A May report by the Polaris Institute (PDF), drawing on government and Enbridge data, identified 49 “significant incidents” on the company’s pipelines between 1999 and 2009. The accidents, in total, resulted in three worker deaths, 26,000 barrels (more than 1 million gallons) of oil and other materials spilled, and more than $30 million in property damage.

Minnesota was the state with the largest number of these incident (18), including a 2002 spill that leaked more than 250,000 gallons of oil into a marsh near the town of Cohasset, previously the company’s largest U.S. spill.

Between 1999 and 2008, according to Enbridge’s own Corporate Responsibility Report, there were 610 spills on the company’s pipeline network, releasing 5.5 million gallons of oil and gas into the environment.

The cause of Monday’s spill, near Marshall, Mich., has not yet been determined.

Ken is the director of the Energy News Network at Fresh Energy and is a founding editor of both Midwest Energy News and Southeast Energy News. Prior to joining Fresh Energy, he was the managing editor for online news at Minnesota Public Radio. He started his journalism career in 2002 as a copy editor for the Duluth News Tribune before spending five years at the Spokesman-Review in Spokane, Washington, where he worked as a copy editor, online producer, features editor and night city editor. A Nebraska native, Ken has a bachelor's degree from the University of Nebraska-Lincoln and a master's degree from the University of Oregon. He is a member of the Society of Professional Journalists and Investigative Reporters and Editors.