Initial cleanup of southwestern Michigan waterways and riverbanks from a July oil spill has been completed and most of the 820,000 gallons that leaked from a ruptured pipeline recovered, officials said Thursday.
Crews continue removing contaminated sediments from the Kalamazoo River bottom and searching out isolated pockets of oil onshore. But the operation is shifting from mopping up oil to a long-range project to restore the area to its pre-spill condition.
"The ultimate goal is to remove all oil from the environment," said Mark Durno, the U.S. Environmental Protection Agency's deputy incident commander. But authorities are leaving some to degrade naturally in sensitive wetlands where cleanup efforts could do more harm than good, he said.
Oil began flowing again this week through the 286-mile-long pipeline, which runs from Griffith, Ind., to Sarnia, Ontario. It had been out of service since the leak was detected July 26 near Marshall. The cause remains under investigation.
Pressure on the repaired pipeline is about 20 percent below normal and will remain so for months to come, said Steve Wuori, an executive vice president of Enbridge Ind., the Canadian company that owns the line.
About 760,000 gallons of crude have been captured, Durno said. Some of the rest remains in the environment, but much has evaporated or was contained in the 70,000 cubic yards of soil that was dug up and removed, he said.
In most cases, "you're lucky to get 30 percent of the oil from a spill collected," Durno said.
Replanted vegetation is growing nicely along the river and Talmadge Creek, the tributary into which the oil initially flowed, he said. Aside from a few faint stains on trees and boulders, visible signs of the spill are mostly gone, he said.
EPA has given Enbridge an Oct. 31 deadline to finish removing oil from about 20 locations along the river bottom. Aside from dredging and digging, teams are stirring the water and pumping in air to send oil to the surface where it can be vacuumed up.
The agency also ordered Enbridge to develop a long-term groundwater monitoring plan.
Michigan's Department of Natural Resources and Environmental Quality will oversee the restoration phase of the cleanup, which will include replanting trees and shrubs, plus water and soil sampling.
"Area residents should be aware that work will be ongoing for many months, if not years, until we are satisfied that all the criteria have been met," DNRE Director Rebecca Humphries said.
Enbridge CEO Patrick Daniel said a dented 3,800-foot segment of pipeline that runs under the St. Clair River would be installed by mid-2011.