TRAVERSE CITY, Mich. — Michigan's two senators called Friday for temporarily shutting down twin oil pipelines in a sensitive Great Lakes waterway that may have been damaged by a ship anchor strike, which also is suspected in the leak of coolant fluid from nearby electric cables.
With an underwater inspection planned for early next week, Democratic Sens. Gary Peters and Debbie Stabenow said oil should not continue flowing through Enbridge Inc.'s Line 5 in the Straits of Mackinac until it's certain the pipes are in good shape. A wintry storm bearing down on the area made the situation more perilous, Peters said.
"Upcoming blizzard conditions and high winds pose a threat to the already-damaged pipeline and —even worse — would render on-site cleanup equipment ineffective in the event of an oil spill," he said. "We simply cannot afford that kind of risk to Michigan's most precious natural resource."
Enbridge spokesman Ryan Duffy said the Canadian company was monitoring the situation and "should the weather deteriorate to a point where we are concerned about the ability for our personnel to respond to an incident, we will temporarily shut down."
Line 5 carries about 23 million gallons (87 million liters) of crude oil and liquefied natural gas daily between Superior, Wisconsin, and Sarnia, Ontario. The segment that crosses the 5-mile-wide (8-kilometer-wide) straits linking Lakes Huron and Michigan is divided into two side-by-side pipes that were laid on the lake bottom in 1953.
Enbridge used mechanical tools to inspect their interior after two electric cables in the vicinity leaked 600 gallons (2,270 liters) of insulation fluid containing mineral oil and benzene earlier this month. One pipe had two small dents and the other had one, the company said, describing them as minor and insisting the integrity of the lines weren't compromised.
The Coast Guard says it's investigating the cause of the electric cable leak and that "vessel activity" may have been a factor. But it has declined to confirm speculation by Gov. Rick Snyder and other elected officials that a dropped anchor was the culprit. The straits area is used frequently by cargo ships and recreational boats.
Peters, who questioned Coast Guard officers about the investigation during a Commerce Committee hearing Thursday in Washington, D.C., said Friday he was told in a separate briefing that a visual inspection was needed to fully assess the extent of the oil pipeline damage.
Enbridge plans to deploy a remote underwater vehicle to examine the pipes' exterior Monday, Duffy said.
The American Transmission Company, owner of the ruined power cables, also plans a separate remote probe of the ruined electric cables next week.
Snyder pressed Enbridge on Wednesday to expedite studies of ways to prevent damage to Line 5 from an anchor, including replacing the pipes with others in a tunnel beneath the lake bed.
Asked Friday for a response to the senators' call for a Line 5 shutdown, Snyder spokeswoman Anna Heaton said Lt. Gov. Brian Calley visited the site earlier this week and met with Coast Guard officials.
"They reported no immediate threat from Line 5," Heaton said. "If we receive any information that indicates an immediate health or safety threat from this source of heat for the Upper Peninsula during the approaching winter storm, we will act accordingly."
The Coast Guard and other agencies have been monitoring the straits by boat and air but have reported no sheen or other evidence of pollution. Those operations were suspended for the weekend because of the expected storm.