Deliveries resumed Wednesday through both pipes in Enbridge Inc.’s 540,000 b/d Line 5 across the lake floor of the Straits of Mackinac in Michigan, after a safety examination shuttered one of the conduits for 11 weeks.

The Pipeline and Hazardous Materials Safety Administration (PHMSA) allowed the Calgary-based operator to restore full capacity. The Michigan Circuit Court also lifted an oil traffic restraining order obtained by Gov. Gretchen Whitmer and Attorney General Dana Nessel in June.

The PHMSA said neither staff nor an independent expert retained for additional checks detected a threat of a leak from a damaged underwater pipe support anchor, which triggered the prolonged safety review.

“We continue to work toward and look forward to the day when a replacement for...