MACKINAW CITY, MI -- Enbridge Energy's Line 5 would gush 2,436,000 gallons of oil, slick 437 miles of Great Lakes shoreline and cost the Canadian company $1.86 billion in damages under a worst-case scenario spill, according to a risk analysis study spearheaded by Michigan Technological University.
According to the study's analysis of 4,300 spill simulations, the worst-case scenario spill would also endanger 47 wildlife species and 60,000 acres of habitat.
The 398-page draft study released Thursday, July 19, is the last of five analyses requested by Gov. Rick Snyder as he deliberates decommissioning and possible alternatives for the twin oil and gas pipelines under the Straits of Mackinac.
Snyder has set a deadline of Sept. 30 to formalize an agreement with Enbridge on the future of Line 5. Members of the public can weigh in on the draft study during a 6 p.m. meeting Aug. 13 at the Boyne Highlands Convention Center in Harbor Springs. The public comment event is hosted by the Michigan Tech team.
For years activists and environmental groups have called on officials to shut down the controversial, aging pipeline. When an anchor struck the lines April 1, it resulted in three dents and an abrasion and renewed calls to shutdown the 65-year-old twin pipelines.
A study commissioned by Enbridge and released in late June determined that implementing a ship warning system and placing piles of fist-sized rocks onto the pipelines is the most viable solution to prevent anchor strikes.
The "Independent Risk Analysis for the Straits Pipelines" was lead by professor Guy Meadows of Michigan Tech's Great Lakes Research Center and involved numerous faculty from nine universities and staff from National Oceanic and Atmospheric Administration.
"The worst-case approach implemented in the study is based on the accumulation of worst-case assumptions and explicitly excludes consideration of the probability of such event," according to a joint release from state officials. "As a result, the assessment extends to events with low probabilities of occurrence but high consequences."
The determined worst-case scenario would damage recreation in 15 counties, impact 13 others to a lesser degree, including the Milwaukee shoreline. Also impacted would be the municipal water intakes of Mackinac Island, St. Ignace, the city of Green Bay, Cheboygan and Manitowoc, the study states.
Counties in green would have damage to recreation and counties in yellow would be impacted to a lesser degree under the worst-case scenario. The red lines indicates oiled shorelines.
The worst-case scenario involves a rupture on both pipelines and failures of safety, detection and automatic shutoff equipment under inclimate weather. The estimated time to manually shut all valves and pumps is two hours, under this scenario.
Enbridge spokesperson Ryan Duffy cautioned against taking the report as something likely to happen.
"The scenarios presented in this report are purely hypothetical and the probability of the events actually occurring is extraordinarily unlikely because Enbridge operates our pipelines with multiple layers of safety in mind," Duffy said.
The measures, Duffy said, include automatic shut-off valves, people equipped for spill response and a 24-hour control center which can begin a pipe shutdown in minutes.
"We all agree that the state's natural resources are a treasure that must be protected," he said. "While Line 5 continues to operate safely, and there never has been a release in the Straits since it was installed, the State and Enbridge are working on new safeguards to enhance pipeline safety."
But not all scenarios in the report are "extraordinarily unlikely."
Even with all systems and responses functioning normally, the more minor spill scenarios of 184,800 to 361,200 gallons of oil released result from a 3-inch "pinhole" leak in one of the twin lines.
"A pinhole leak could plausibly be caused by corrosion, defects, fatigue or third party damage, with fatigue being most likely," the report states.
The study pointed to past issues of coating gaps on the lines which left bare metal exposed to the environment and corrosion. Enbridge previously said no corrosion on gap sites were detected.
"Even though no evidence of metal loss was found to date, the absence of coating increases the probability of corrosion and thus could plausibly contribute to future pinhole leakage," according to the report.
Because the study set out to assess the worst-case scenario, it did not estimate what damage these more minor spills would cause.
Keith Creagh, director of the Michigan Department of Natural Resources and co-chair of the Pipeline Safety Advisory Board, said Line 5 "cannot remain in the Straits in its current form."
Mike Shriberg, regional director of the National Wildlife Federation and a member of the Pipeline Safety Advisory Board, called into question the study's assumed quick response by Enbridge.
"One assumption that jumps out is that Enbridge would detect a leak within 5 minutes or less, when it took them 17 hours to detect the Kalamazoo River oil spill and weeks to assess the damage caused by this past April's anchor strike," he said. "Given Enbridge's track record, a 5-minute detection time seems closer to a best-case scenario, not a worst-case."
During the 2010 Kalamazoo River oil spill, Enbridge failed to recognize that Line 6B had ruptured until at least 17 hours afterward, causing 843,000 gallons of heavy crude oil to spill.
Lisa Wozniak, executive director of the Michigan League of Conservation Voters, again called on state leaders to shut down the aging pipeline and not replace it with an alternative.
"Each day oil pumps through Line 5 under the Straits of Mackinac is another day we risk an oil spill that would devastate our precious Great Lakes, upend our recreation and tourism industries and cost our state billions of dollars," Wozniak said. "Today's report reinforces the fact that oil pipelines do not belong in the Great Lakes."
The Line 5 pipeline, built in 1953, runs 645 miles from Superior, Wisconsin, to Sarnia, Canada, and transports up to 540,000 barrels of light crude oil and natural gas liquids per day.