Update 4/4/19: The story has been updated to include comments from the U.S. Coast Guard and Enbridge.
An activist group wants to know what happened during an anchor strike on the Line 5 oil pipeline.
Last April, a tugboat dragged its anchor along the bottom of the Straits of Mackinac, damaging the pipeline.
Straits of Mackinac Alliance Chairperson Patty Peek says they want a U.S. Coast Guard report that shows how much the Straits are at risk.
"What it says to us is that if there was a real event from Enbridge's pipeline number five where there was a significant oil spill that, there may not be an ability to gather that oil up and protect our waters," she says.
Peek says the amount of ice cover and weather conditions can make it hard to quickly respond to a leak. She also says the various currents on the Straits could make the cleanup effort much harder.
U.S. Sen. Gary Peters (D-Mich.) has asked for the report and says his office will closely monitor the situation.
A Coast Guard spokesperson says the report has concluded at the local level and has been sent to another office for review and further investigation. He says the report will be made available to the public when it is complete.
Enbridge, which owns Line 5, says the proposed tunnel project in the Straits would stop an anchor strike from causing damage.
"The Line 5 tunnel project in the Straits of Mackinac would reduce the chance of any product being released to near zero, because the Line would be 100 feet below the lakebed, in a tunnel with foot thick concerte walls," says spokesperson Ryan Duffy.