Enbridge Line 5 is a 645-mile oil pipeline owned by the Canadian multinational corporation Enbridge. Constructed in 1953, the pipeline conveys crude oil from western Canada to eastern Canada via the Great Lakes states. Line 5 is part of the Enbridge Lakehead System and passes under the environmentally-sensitive Straits of Mackinac, which connect Lake Michigan to Lake Huron. The 30-inch pipeline carries 540,000 barrels (86,000 m3) of synthetic crude, natural gas liquids, sweet crude, and light sour crude per day as of 2013.