An unsupported span of Enbridge Energy’s Line 5 oil pipeline beneath the Straits of Mackinac has grown to 81 feet, surpassing the 75-foot limit outlined in the company’s easement agreement with the state.

Enbridge notified the state of the development Wednesday and said it applied for approvals to place screw anchors or supports along that segment of the pipeline in March 2018 but is still waiting on an answer for the U.S. Army Corps of Engineers. The Canadian company said it already has received state permits for the work from the Michigan Department of Environment, Great Lakes and Energy.

The unsupported span measured 66 feet last summer, but officials discovered it had grown to 81 feet last month, Enbridge spokesman Ryan Duffy said Wednesday. The company's easement agreement allows for a 90-day window in which to address the unsupported span, he said.

Exposed sections of the Line 5 oil pipeline that don’t lie on the lake bed are required to have supports or screw anchors attached to them at least every 75 feet. The areas needing support change from year to year as soil washes away or erodes.

"Since learning about it, we’ve been talking with the Army Corps and have told them we want to get out there as quick as we can," Duffy said.

Gov. Gretchen Whitmer's office learned of the span's situation Wednesday and is reviewing the information Enbridge provided, Whitmer spokeswoman Tiffany Brown said.

The news from Enbridge "reinforces the need to decommission Line 5 as quickly as possible," Attorney General Dana Nessel's spokeswoman Kelly Rossman-McKinney said.

"We know the currents in the Straits of Mackinac are complex, variable, and remarkably fast and strong — clearly strong enough to erode an additional 15 feet of bottom land that was supporting the pipeline within the last year," Rossman-McKinney said in a statement.

"This erosion makes the 66-year-old pipeline increasingly vulnerable to anchor strikes and potential ruptures and reinforces the need for the legal action Attorney General Nessel has taken to remove the pipeline from the Straits.”

Enbridge's request to the Army Corps and state Department of Environment, Great Lakes and Energy was for a total of 54 screw anchors to place along the entirety of the line, Duffy said. But he noted that the plans for a tunnel to house the pipeline were the most ideal long-term solution to address the issue.

"There wouldn’t be spans needing the supports if the tunnel was built and the line was in the tunnel," Duffy said.

The idea of placing screw anchors along the pipeline is not embraced by all environmental groups as it could lift the line farther off the lake bed, further exposing it to currents and anchor strikes, said Sean McBrearty, campaign coordinator for Oil and Water Don't Mix.

"This is just another sign that the pipeline needs to be decommissioned as soon as possible like the attorney general’s lawsuit seeks to do," McBrearty said. He suggested Wednesday was one of the first times Enbridge reported a suspected easement violation "without environmental groups or the state finding that violation and making it public.”

The company notified the state of the issue Wednesday to maintain compliance with one of the agreements it made with the state in 2018 that required Enbridge to report any issues related to the spans on the roughly 4-mile pipeline within 30 days of discovery. Nessel has since opined that the agreement is unconstitutional.

"Enbridge is reporting the span length on this one span because it believes its agreement with the state is valid," the company said in a statement. "We remain in compliance with the easement."

The disclosure of the lengthening unsupported span comes as Enbridge is suing the state regarding the future of Line 5.

One lawsuit seeks a court ruling on the validity of the 2018 agreements with the state that cemented plans for the construction of a $500 million utility corridor beneath the Straits of Mackinac to house Line 5.

A second lawsuit filed by Nessel seeks a court injunction on the operation of Line 5 by alleging that Enbridge is violating its easement by continuing to operate its 66-year-old dual pipelines in the Straits.

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