TRAVERSE CITY (AP) — Enbridge’s plans for drilling an oil pipeline tunnel beneath a channel linking two of the Great Lakes do not meet industry standards and pose significant hazards to workers and the environment, experts who reviewed project documents on behalf of opposition groups told The Associated Press.

Two geologists and a hazardous waste specialist said they found numerous shortcomings with the Canadian company’s proposals to the Michigan Department of Environment, Great Lakes and Energy, which is considering whether to allow construction of the tunnel under the Straits of Mackinac.

“What Enbridge has submitted to the state of Michigan doesn’t come close to properly designing and preparing for a tunnel underwater,” said Brian O’Mara, a geological engineer who has worked on dozens of tunnel projects.

The analysis was requested by Oil & Water Don’t Mix, a coalition of environmental, business and tribal organizations. They are fighting to shut down Line 5, an Enbridge pipeline that crosses the bottom of the waterway connecting Lake Michigan and Lake Huron.

Enbridge spokesman Ryan Duffy said the tunnel plans were developed in consultation with experienced geologists and engineers.

Jay Dee Contractors Inc. and the U.S. affiliate of Japanese tunnel construction firm Obayashi Corp. are constructing the tunnel. Arup, an engineering and consulting firm, is helping with design.

“Jay Dee and Obayashi have a collective track record of constructing more than 400 pressurized-face tunnels consisting of more than 2.4 million feet (about 732,000 meters) of tunnelway,” Duffy said. “A number of those projects involved high pressure and ground condition parameters similar to those that will exist in the Straits of Mackinac.”

The company contends the 67-year-old Line 5 that runs between Superior, Wisconsin, and Sarnia, Ontario, is in good condition but wants to replace the 4-mile-long (6.4-kilometer-long) underwater segment with another to be housed in a nearby subterranean tunnel. Enbridge says it would pay the estimated $500 million cost.

Opponents planned to release their reviewers’ findings at a news conference Monday.