ST. IGNACE, MI -- Michigan officials are demanding information from Enbridge Inc. about several areas where protective coating has been lost down to the bare metal on the company's Line 5 oil pipeline under the Straits of Mackinac.

Enbridge says two, possibly three areas of the twin underwater pipeline are entirely missing the protective coating that keeps the pipeline from corroding, and the gaps were caused during previous work on the line.

The news prompted a statement from Gov. Rick Snyder, who has said little to date about the controversial pipeline.

"Protection of Michigan's natural resources is of utmost importance, and I am greatly concerned by the new information regarding Line 5," Snyder said. "I have directed our departments to accelerate an aggressive review of Enbridge operations and maintenance procedures throughout the state."

The company disclosed the findings in a letter to Michigan tribal leaders this week and notified the Environmental Protection Agency.

"We believe its tied to previous anchor installation work we've done where we bumped the pipe during that or other construction work," said Ryan Duffy, Enbridge spokesperson.

"We confirmed this within the last two weeks."

In March, Enbridge denied there were any areas of bare pipeline metal exposed to water during a state pipeline board meeting presentation on confirmed areas where the outer-wrap coating had failed.

One confirmed bare metal spot is on the west pipe leg, the other confirmed and suspect spots are on the east leg, Duffy said. One spot is "Band-Aid" sized, about three inches by a half inch.

He couldn't estimate how long the bare metal had been exposed. Despite the coating gaps, "we haven't had any corrosion whatsoever."

Enbridge says the coating gaps are not evidence of immediate danger to the pipeline integrity because Line 5's cathodic protection has not been compromised. State officials nonetheless issued strongly worded statements on Wednesday afternoon, Aug. 30, expressing displeasure at the coating gaps and calling for immediate repair.

The Michigan Agency for Energy, Department of Environmental Quality, Department of Natural Resources and State Police are jointly demanding immediate inspection around every Line 5 anchor, a report on the findings, video of recent work performed on the pipeline and repair within 30 days of any damage to the coating.

Attorney General Bill Schuette issued a statement expressing "great concern."

"We need to focus on a timeline to close Line 5, with a defined plan to ensure that Michigan residents in the UP have reliable access to propane and protect our lakes with sound science and modern regulatory policy," he said.

DEQ director Heidi Grether called the situation "unacceptable."

"The possibility this loss of coating occurred during the anchor installation process and was not immediately addressed is completely unacceptable," she said.

The DEQ and the U.S. Army Corps of Engineers are presently reviewing a permit request by Enbridge to install 22 anchors on the pipeline, which the company says are needed to proactively guard against areas where currents wash away the lakebed underneath.

Grether said Enbridge must, "at minimum," submit any video it has of previous anchor installation work. The company installed four anchors on the pipeline last fall.

"I want a greater assurance that the integrity of all aspects meant to protect the Great Lakes is the company's utmost priority," she said.

MAE director Valerie Brader cited the human error aspect.

"The fact that human error, not a mussel, created them is something that raises real concern," said Brader.

"Human error was a major factor in Enbridge's spill into the Kalamazoo River. These coating gaps point to other areas where human error, not the environment, are creating problems," she said.

Enbridge has parked a barge over the pipeline for the past couple weeks while inspecting the impact invasive zebra and quagga mussels are having on the pipeline coating. The work is required by a 2016 settlement with the federal government over the 2010 spill.

Duffy said Enbridge plans to make repairs as soon as possible, but is exploring whether it needs to obtain any special state or federal permits for the work.

Liz Kirkwood, a leading advocate for shutting down the pipeline, suggested the coating loss represents a violation of Enbridge's 1953 easement with the state.

"I think the ball has shifted back into the state's hands to enforce the expressed terms of the easement because it's clear that Enbridge is not acting as a reasonable prudent person as required," said Kirkwood, director of the nonprofit FLOW.

"This is further evidence of lack of stewardship and transparency."

Lisa Wozniak, director of the Michigan League of Conservation Voters, said the news "only strengthens the case for the Snyder administration to do what needs to be done by shutting down this out-dated, poorly maintained, and dangerous pipeline."