The U.S. Environmental Protection Agency estimated more than 23,000 barrels of heavy oil from Alberta tar sands spilled in 2010 from a pipeline into the Kalamazoo River and nearby Talmadge Creek.
Enbridge Energy, the operator of the ruptured Line 6B of the Lakehead pipeline system, has since worked to clean up the surrounding community as tar sands oil tends to linger in the environment longer than conventional crude.
The Michigan Department of Community Health, in its final public health assessment, said there were no lingering heath concerns from contact with the spill.
"MDCH has concluded that contact with the submerged oil will not cause long-term health effects or a higher than normal risk of cancer," the agency stated. "At the same time, contact with the submerged oil may cause temporary effects, such as skin irritation."
The agency noted, however, that its assessment dealt with direct contact with submerged oil, not vapors associated with spilled oil.
Enbridge in May reported to Michigan regulators that it planned to replace more than 200 miles of Line 6B.