A Canadian energy company has defied an order from Michigan Gov. Gretchen Whitmer to shut down a controversial oil and gas pipeline Wednesday amid growing concern that doing so could lead to fuel disruptions similar to those resulting from last week’s cyberattack on an East Coast system. The Democratic governor gave Canadian pipeline company Enbridge until Wednesday to shut down Line 5, which runs under the Straits of Mackinac, amid fears that it could spill in a channel linking two of the Great Lakes. “These oil pipelines in the Straits of Mackinac are a ticking timebomb, and their continued presence violates the public trust and poses a grave threat to Michigan’s environment and economy,” Whitmer’s office said in a statement. However, Enbridge refused to comply with the order, saying that only the federal government has regulatory authority over its operations. It says leaks have never occurred in the underwater section …