Nearly 150 Michigan residents were treated for symptoms such as nausea and headaches in the aftermath of Enbridge’s oil spill two years ago, but it’s the potential for long-term health effects that has experts most worried.

Documents obtained through the Michigan Department of Community Health reveal that 145 people were treated by health care providers after the July 25, 2010 spill that polluted local wetlands and the Kalamazoo River, and 320 locals reported experiencing illnesses in surveys.

A total of 41 calls were also made to poison control, the most common symptoms being headaches, nausea, vomiting and respiratory problems.

Among those affected was Michelle Barlond-Smith, who said her stomach felt like it “had rocks in it.”

“You had nausea, you didn’t want to eat,” Barlond-Smith told CTV News. “I don’t want anyone to ever go through what we’ve gone through here.”

Health Officer Jim Rutherford of the Calhoun County Health Department said officials had their hands full for the first two to four weeks after the spill, but the short-term symptoms were identified and treated.

What they’re less clear about are the long-term impacts residents may face.

“It’s such a significant incident that it’s just not going to go away overnight. We’ve got remnants of submerged oil, and what does that mean five years from now? That’s the big question for me,” Rutherford said.

The state health department refused to launch a long-term study on the issue due to the cost, however, instead concluding that the oil remaining in the Kalamazoo River “will not result in long-lasting health effects” or a “higher than normal risk of cancer.”

Enbridge agrees, assuring that is has been monitoring ground water and no contamination has been reported.

“There was never any effect on water wells,” said Stephen Wuori, president of Enbridge pipeline operations. “And the air quality issue went away relatively quickly.”

Some in the research community aren’t so sure, though, and are warning British Columbians about the potential harms they could face should the Northern Gateway pipeline be approved and result in a spill.

Marine toxicologist Dr. Ricki Ott has been studying the health impacts of oil spills for years, and has been featured in multiple award-winning documentaries about the Exxon Valdez disaster. She now fears the Michigan spill could have been a “triggering event” for illness.

“In other words, it can trigger illnesses that your body is carrying but hasn’t expressed yet because your body successfully fought back,” Ott said. “And it can weaken your body to the extent that other illnesses will crop up.”

The Northern Gateway pipeline, as it’s proposed now, would run through a number of B.C. communities –Burns Lake, Bear Lake and Kitimat, to name a few – creating the potential for human contact in the event of a spill.

There is currently no evidence to prove Michigan residents will experience long-term impacts, but many say they’re still wary about swimming in certain local waters.

While public health officials reopened most of the Kalamazoo River in the spring, sections of Morrow Lake remain closed as the cleanup continues two years later.

“It’s still dirty, it’s nasty,” said Fred Lutz, a local who has been swimming in the river since he was a child. “It’s not a good sight.”

With a report from CTV British Columbia’s Scott Roberts