The Canadian company Enbridge held an emergency response exercise in the Straits of Mackinac Thursday, testing the company’s readiness in the event of a break in Line 5, the pipeline which runs under the Straits that has continually pumped light crude oil and natural gas liquids since its construction in 1953. The exercise involved nearly 500 specialists from local, state, and federal agencies, which included the U.S. Coast Guard, The U.S. Environmental Protection Agency, the U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration, The Michigan Department of Environmental Quality, the Michigan Department of Natural Resources, and local emergency and law enforcement. Raven Security, of Southfield, Mich., was also on scene at all individual sites during the exercise providing crowd and vehicle control and monitoring of the overall operation.