A Michigan regulatory agency has denied Enbridge's request for quick approval of its plan to put a replacement oil pipeline beneath a Great Lakes channel. The state Public Service Commission on Tuesday voted to conduct a full review of Enbridge's proposal. Enbridge wants to extend the pipeline through a tunnel that would be drilled beneath the Straits of Mackinac, connecting Lakes Huron and Michigan. It would replace dual Line 5 pipes that lie on the bottom of the straits. The company contends it doesn't need the public service commission's approval for the new line because the agency allowed the original pipes in 1953.