Canadian energy distributor Enbridge was working Wednesday to contain more than three million litres of oil that leaked from one of its pipelines in southern Michigan, damaging water and wildlife in the Kalamazoo River.

The 41-year-old pipeline belonging to the Calgary-based company usually carries about 30 million litres of oil daily to Sarnia, Ont., from Griffith, Ind.

Enbridge said Wednesday it is doubling its work force on the containment and cleanup effort in affected areas, including the Kalamazoo, which is one of the state's major waterways and empties into Lake Michigan.

About 300 employees and contractors are trying to contain the spill, and the company is adding more barricades in nearby waterways to help contain the leaked crude, officials said.

'Our intent is to return your community to its original state and the waterways to their original state.'— Patrick Daniel, Enbridge CEO

"We've made significant progress," Enbridge CEO Patrick D. Daniel said. "But we still have a long way to go in terms of cleanup."

The U.S. Environmental Protection Agency also was bringing in additional contractors. There was no update on a possible cause, cost or length of cleanup.

"Our intent is to return your community to its original state and the waterways to their original state," Daniel said at a media briefing Wednesday.

Enbridge came under some fire initially from Michigan Gov. Jennifer Granholm for an "anemic" cleanup effort.

Granholm declared a state of disaster in Calhoun County and potentially affected areas along the river, which eventually bisects the city of Kalamazoo and meanders to Saugatuck.

Officials don't believe oil will spread past a dam upstream of Kalamazoo.

Enbridge said Wednesday it already had roughly 4,200 metres of absorbent booms on the water and vowed to increase that to 13,700 metres at 10 additional sites along the river.

Stay away from Kalamazoo River, officials warn

Many area residents were surprised to learn that a pipeline was so close to the Great Lakes river.

"I just can't believe they allowed that to happen, and they're not equipped to handle it," said Owen Smith, 53, of Galesburg, Mich.

Smith lives near the river and stopped at several points far upstream on Tuesday to see what might be headed his way.

The air was pungent with the smell of oil, but health officials said they have been satisfied with the results from air quality tests so far. Groundwater testing is expected to begin soon.

Still, health officials warned residents to stay away from the river, saying it should be closed to fishing and other recreational activities, and irrigation. No injuries or illnesses have been reported, but a few households near the spill have been evacuated.

"It was really strong. It was an irritating smell, burned my eyes and nose, and my son was sick and my wife's pregnant," said Battle Creek resident Jim Gantz. "So we called them and they said call this number, they gave us a number and it was a man from Enbridge Oil Company and he said get out."

Local, state and federal agencies also are involved, and the National Transportation Safety Board has launched an investigation. Crews have started to dig up the pipe to try to determine exactly what caused the leak.

U.S. President Barack Obama has pledged a swift response to requests for assistance, White House spokesman Matt Lehrich said.

The river already faced major pollution issues. A 128-kilometre segment of the river and eight kilometres of a tributary, Portage Creek, were placed on the federal Superfund list of high-priority hazardous waste sites in 1990.

The Kalamazoo site also includes four landfills and several defunct paper mills.

Greenpeace protests at Enbridge's Vancouver office

Meanwhile, Greenpeace protesters staged a mock oil spill Wednesday at the downtown Vancouver office of Enbridge, after the pipeline company took responsibility for the spill.

The protesters were trying to draw attention to an Enbridge proposal to build a 1,000-kilometre pipeline from the Alberta oilsands to the West Coast in B.C.

The proposed project has generated opposition from First Nations and environmental groups that fear a spill could jeopardize the environment.

With files from The Associated Press