(MARYSVILLE) — Officials from the U.S. and Canada plan to join pipeline operator Enbridge to conduct an oil spill response exercise next year in the St. Clair River. Rick Loster, port security specialist with the U.S. Coast Guard in Detroit, says the full-scale exercise will simulate a 13-minute, 5,000-barrel break in Line 5 at Marysville. The date for the exercise is May 25 with a rain date set June 2. The exercise follows a similar one in September involving local, state and federal agencies as well as Enbridge crews. That drill simulated a leak from Line 5 in the Straits of Mackinac. The pipelines are part of a network that runs from North Dakota to Sarnia, Ontario. Enbridge says Line 5 is safe, but environmental groups want it shut down.