Enbridge Inc. needs to dredge sections of the Kalamazoo River in Michigan to remove sediments tainted by oil from a massive spill back in July 2010, Environmental Protection Agency (EPA) officials said.
When the original incident occurred, more than 800,000 gallons spewed into the river and a tributary creek after the rupture of an underground pipeline near Marshall in southwestern Michigan. Oil flowed about 35 miles before containment.
An investigation by the National Transportation Safety Board determined the rupture was the result of cracks and corrosion, and the agency faulted Enbridge for failing to take steps that might have prevented it.
The EPA said it confirmed the presence of submerged oil in three areas and determined Enbridge could remove it through dredging.
“The dredging activity required by EPA’s order will prevent submerged oil from migrating to downstream areas where it will be more difficult or impossible to recover,” said officials at the agency’s regional office in Chicago. In a letter to the company, it said the dredging will protect public health and the environment.
The Canadian company has five days to respond to the order and 15 days to provide a work plan. The dredging should begin this spring and is not expected to require closing any of the river, the EPA said.
Enbridge, based in Calgary, Alberta, said it would “study the order in detail and respond accordingly.”
The targeted areas are above Ceresco Dam, upstream from Battle Creek and in the Morrow Lake Delta. The agency also told Enbridge to keep sediment traps in the river to capture oil where they do not have to do dredging.
“We are, as we have always been, focused on cooperation with the EPA and other authorities in doing what is best for the river and the environment based on analysis and sound science,” said spokesman Jason Manshum.
The company acknowledged some oil remains in the river but said it is weathered, degraded and “in extremely small concentrations.” It said the Michigan Department of Community Health had found that incidental contact with the oil would not pose a hazard and that water from private wells near the river was safe to drink.
The EPA initially proposed the additional cleanup work last October and issued the final order Thursday after taking comments from the company and the public.
The agency said it used a method called “poling” to locate the submerged oil. It involves stirring up soft sediments using a pole with an attached disc, causing oil to rise to the surface.
Enbridge response to EPA’s October proposal questioned the accuracy of data from poling and contended there was no immediate need for containment or recovery actions.
The 286-mile-long pipeline extends from Griffith, Ind., to Sarnia, Ontario. Enbridge is replacing and enlarging the line, part of a $2.6 billion project to boost the flow of oil to refineries in the eastern U.S. and Canada.