Larry Peplin for Crain's Detroit Business The Marathon refinery in Detroit is partially supplied by liquids carried by Line 5 and provides 18 percent of Michigan's petroleum products. A coalition of chambers of commerce for Canada, the U.S., Michigan, Wisconsin and Ohio have mounted a united front against Gov. Gretchen Whitmer's attempts to have Enbridge Inc.'s Line 5 oil pipeline shutdown today, arguing such a move would trigger "energy emergencies" in both countries. The U.S. Chamber of Commerce, Canadian Chamber of Commerce and Wisconsin and Ohio's chambers joined the Michigan Chamber of Commerce on Wednesday in filing an amicus brief in a federal lawsuit involving Enbridge's continued use of twin underwater pipelines that carry 540,000 barrels of oil daily across the environmentally sensitive waterway connecting Lakes Huron and Michigan.