(Michigan News Connection) The U.S. Army Corps of Engineers has announced an 18-month delay in permitting a controversial oil-tunnel construction project under the Great Lakes.

Federal engineers said they need the extra time to study the massive volume of public comments submitted about the project.

Sean McBrearty, campaign coordinator for the conservation group Oil and Water Don't Mix, said the delay will push builder Enbridge's Line 5 project well beyond its original timeline.

"This was entirely predictable," McBrearty asserted. "From the beginning, Oil and Water Don't Mix, and our allies have been saying that this is going to take a lot longer than what Enbridge was trying to sell, and that likely this project will not be able to be permitted."

Line 5 is a pair of aging oil pipelines under the Mackinac Straits Enbridge wants to replace with an underground tunnel. Conservation groups oppose the project over its potential to damage the environment. A spokesman said Enbridge is "disappointed with the delay."

McBrearty emphasized environmental groups want the pipeline closed down, predicting a leak or a break under the lakes could bring damage which could last a generation or longer. He added many experts question the safety of building an underwater oil tunnel.

"We have a 70-year-old pipeline pumping 23 million gallons of oil a day, through the worst spot in the Great Lakes for an oil spill," McBrearty pointed out. "The oil tunnel may never exist, but the pipeline sitting at the bottom of the Straits of Mackinaw does exist."

A coalition of Michigan conservation groups, Native American tribes and elected officials are pushing the Biden administration to shut down the current pipeline. The original timeline for completing of the tunnel project, which could cost $2 billion, was 2024, but if it is built, it will won't be completed until 2029.