The Michigan attorney general's office has opened an investigation into a massive oil spill in the Kalamazoo River.

Mike Cox made the announcement about the probe on Friday. He's one of five Republicans running for governor.

Cox is one of several gubernatorial candidates who have toured the spill area this week.

AG's office spokesman John Sellek says Michigan law gives the state the power to deal with water quality separately from the actions of the U.S. Environmental Protection Agency.

The canadian company that owns the pipeline that leaked the oil also said Friday the oil has been contained.

Enbridge Inc. says on its website its focus is shifting to cleaning up the spilled oil, which it estimates at 820,000 gallons. The Environmental Protection Agency puts the total at over 1 million gallons.

Officials say they don't believe the oil will reach Lake Michigan, where the river empties. EPA says the oil appears to be contained near a spot on the river some 80 miles east of the lake.

RAW:Images:

Calgary, Alberta-based Enbridge said Wednesday that it had redoubled its efforts to clean up the mess. Chief executive Patrick D. Daniel said the company had made "significant progress," though he had no update on a possible cause, cost or timeframe for the cleanup.

On Thursday, the company said it was bringing in additional resources as quickly as possible.

Tom Sands, deputy state director for emergency management and homeland security, said during a conference call with Granholm that he had seen oil past a dam at Morrow Lake. The lake is a key point in the river near a Superfund site upstream of Kalamazoo, the largest city in the region.

But his report could not be immediately confirmed. The company's latest update statement Wednesday said oil was about seven miles short of the opening to Morrow Lake. A press conference scheduled for late Wednesday, which was to include company and EPA officials, was canceled for what a company spokesman called scheduling conflicts.

State and company officials previously said they didn't believe the oil would spread past that dam.

"It's going to hit a Superfund site unless somebody like the EPA and the company get very serious about providing significant additional resources," Granholm said.

The spill has killed fish and coated wildlife as it made its way westward about 35 miles downstream past Battle Creek, a city of 52,000 residents about 110 miles west of Detroit.

Watch:Watch:

A wildlife rehabilitation center has been opened in Marshall Township by the federal officials and Enbridge Inc.

A volunteer group set up shop near the rehabilitation center and is collecting donated dish soap and other materials to assist the effort.

Circle D Wildlife Refuge has sent up a center in Vicksburg, about 30 miles from Battle Creek, where animals found covered in oil can be brought to be cleaned. Volunteers said several geese have been found by residents wandering through back yards. Several dead birds have been found along the riverbank.

Wildlife volunteer Jeff Decuypere said he's fighting with the government to run his rescue center. Although his refuge is licensed with the U.S. Fish and Wildlife Service, Decuypere said he's being told to stay away from the animals because the service only wants to run one official center. But Decuypere said he's willing to go against their wishes in order to save the animals.

Decuypere said he's heard from many people that they are not getting any answers from the service when they call to report oil-covered animals they find.

"Ninety percent of the reports we're getting is that they're not responsive," he said.

Watch:

A duck and Canadian goose were the first animals Decuypere and his volunteers treated. They were cleaned with vegetable oil, Dawn soap a toothbrush and warm water.

"It's frustrating to know that this can happen in the Midwest. We're not on the Gulf, we're not by the ocean. This just doesn't happen in Michigan," one volunteer said.