U.S. pipeline regulator notified of concern over Great Lakes pipeline WASHINGTON, Dec. 12 (UPI) -- U.S. senators from the Great Lakes region expressed concern to federal pipeline regulators about the safety of an oil pipeline in the Straits of Mackinac. U.S. Sens. Dick Durbin, D-Ill., Carl Levin, D-Mich., and Debbie Stabenow, D-Mich., expressed concern to the federal Pipeline and Hazardous Materials Safety Administration about Line 5, an oil pipeline operated by Enbridge Energy Partners. Enbridge announced recently it was sending another 50,000 barrels of oil per day through the 60-year-old pipeline, which runs beneath the Mackinac Bridge in the Straits of Mackinac. "If the pipeline running beneath the Straits of Mackinac were to leak or burst, it could have devastating effects on the Great Lakes and the entire region's economy," the senators said in a letter Wednesday. The Great Lakes constitute 95 percent of the nation's surface fresh water supply and are directly connected to more than 1.5 million jobs, with $62 billion in annual wages. The senators said the PHMSA labeled the Straits of Mackinac a high risk area. Enbridge pipeline Line 6b ruptured in southern Michigan in 2010, resulting in one of the worst incidents of onshore oil pollution in U.S. history. There was no statement from the PHMSA or Enbridge in response to the letter.