It came as bad news late last week that an enamel coating on a section of the controversial twin petroleum pipelines that sit on the bottom of the Straits of Mackinac has sustained some degree of damage.

It came as shocking news that the company that owns and operates the lines — Enbridge — knew about the damage for some years and for reasons that remain murky at this writing, chose to keep that information to itself — after saying the polar opposite about six months ago.

Line 5, which carries up to 23 million gallons of light crude oil and liquid natural gas daily across parts of northern Wisconsin and Michigan to refineries in Sarnia, Ontario, has been the subject of significant interest and attention, by both private environmental groups and the state of Michigan.

Enbridge has maintained that the pipes, which are 64-years old, are in good condition and pose no hazard. The state has been investigating and in March, Enbridge officials told the Michigan Pipeline Safety Advisory Board they knew of no places where bare metal was exposed on the underwater sections, which spokesman Ryan Duffy said was “accurate to the best of their awareness,” the Associated Press reported.

But late last week, company officials changed their tune, conceding they knew since 2014 that the enamel had been damaged during the installation of line supports.

The news hit like a bombshell. Valerie Brader, executive director of the Michigan Agency for Energy and co-chair of the Michigan Pipeline Safety Advisory Board, said Enbridge should apologize for not providing the information earlier, AP reported.

“This issue is too important to the people of Michigan not to tell the truth in a timely manner, and right now any trust we had in Enbridge has been seriously eroded,” Brader said.

“I am concerned by Enbridge’s lack of transparency when it comes to Line 5,”said Capt. Chris Kelenske, deputy state director of emergency management and homeland security.

It’s inconceivable that Enbridge didn’t fully grasp the importance of full disclosure as the line has been subject to significant controversy.

For their part, company workers are repairing the damage to the coating. Damage to its relationship with state regulators and the public is another matter.