The hidden, long-term effects of the 2010 pipeline accident that spilled more than a million gallons of heavy Canadian crude oil into Michigan's Kalamazoo River became public last week when the EPA revealed that large amounts of oil are still accumulating in three areas of the river.
The problem is so serious that the EPA is asking Enbridge Inc., the Canadian pipeline operator, to dredge approximately 100 acres of the river. During the original cleanup effort, dredging was limited to just 25 acres because the EPA wanted to avoid destroying the river's natural ecology. The additional work could take up to a year and add tens of millions of dollars to a cleanup that has already cost Enbridge $809 million.
The EPA notified Enbridge of its proposed order on Oct. 3, saying the additional clean-up is "critical" and the work "should be conducted in an expeditious manner" to remove the oil before it recontaminates the river.
"The increased accumulation demonstrates that submerged oil is mobile and migrating, evidencing that submerged oil removal is warranted to prevent downstream migration ... ," Ralph Dollhopf, the EPA's on-scene coordinator and Incident Commander, said in the letter notifying Enbridge of the agency's findings.
In June an InsideClimate News investigation revealed that the cleanup of the Kalamazoo has been unusually difficult, because the pipeline that ruptured was carrying dilbit, a mixture of heavy Canadian bitumen that has been diluted with liquid chemicals, some of them toxic. Bitumen, also known as tar sands oil, has the consistency of peanut butter and is too heavy to flow through pipelines without being thinned with chemicals. When Pipeline 6B split open, the chemicals began evaporating and the reconstituted bitumen began sinking to the river's bottom.
"More than two years after the spill of diluted bitumen, this proposed order demonstrates that EPA is still tackling the problem of how to remove the heavy oil from the Kalamazoo River," said Sara Gosman, an adjunct professor of environmental law and policy at the University of Michigan Law School.
The EPA's determination that more cleanup is needed was based on the findings of a year-long survey of nearly 6,000 locations along the 40 miles of river contaminated when pipeline 6B ruptured in July 2010. Enbridge has until next week to request a conference with the EPA to discuss the additional work and 30 days to submit written comments.
Steve Hamilton, a Michigan State University professor who was among the experts who worked on the study, said the recommendation for dredging was driven by concern that during flooding the pools of oil could break loose and recontaminate parts of the river that have already been cleaned—or flow downriver into areas that were never touched by the gooey oil.
"We will never get all of the oil out [of the river]. It's impossible," Hamilton said. "The challenge is to determine when do you get to a point of diminishing returns where the eradication is too environmentally destructive to warrant the removal."
The EPA acknowledged in the proposed order that Enbridge had conducted substantial cleanup since the pipeline ruptured, but "despite these response actions, oil remains in the Kalamazoo River."
Enbridge did not respond to requests for comment for this story. But in an Aug. 24 letter to the EPA, the company said it did not believe that more dredging—especially in the area near the Ceresco Dam—was necessary.
"Enbridge's position is that we have reached a point of diminishing returns where further invasive activities would do more harm than good," Richard Adams, Enbridge's vice president of field operation in the United States, said in the letter.
"In fact, we strongly believe that such action solely for the purpose of aesthetics would both negatively impact the riverine environment and create a significant disturbance and inconvenience to local landowners and other river users."
The company also disputed the EPA's concern that oil is still pooling in the river, especially near the Ceresco Dam.
"[T]he most significant evidence of submerged oil has been sheen which, when collected, has amounted to a volume of less than 1 gallon of product in total during 2012," Adams wrote, referring to the area around the dam.