Line 6B of the Lakehead oil pipeline system burst July 26, 2010, near Marshall, Mich. The U.S. Environmental Protection Agency said it estimated more than 23,000 barrels of so-called heavy oil spill into regional waters.
Beth Wallace, a regional outreach coordinator for the National Wildlife Federation's Great Lakes Regional Center, said there was "a long way to go" to restore the Kalamazoo River more than a year after the spill.
Line 6B carried oil from tar sands in Canada. While some of the compounds evaporated or naturally degraded, environmental groups note heavy oil from Canada usually sinks, complicating cleanup efforts.
"Pipelines were not built or regulated for tar sands oil," Wallace was quoted by the Battle Creek Enquirer as saying.
Enbridge has worked for most of the year with crews from the Environmental Protection Agency. U.S. Rep. Fred Upton, R-Mich., chairman of the House Energy and Commerce Committee, in March claimed the EPA is made up of "unelected bureaucrats" who are throwing up "roadblocks to domestic energy production."
He recently threw his support behind the Keystone XL pipeline, a planned pipeline for heavy Canadian crude.
U.S. Rep. Tim Walberg, R-Mich., told the Enquirer, however, that he was "concerned" about pipeline safety in his state.