TRAVERSE CITY, Mich. (AP) — Enbridge Inc. will enlarge a pipeline that ruptured nearly two years ago in southwestern Michigan so it can carry more oil from deposits in western Canada and North Dakota, a company official said Thursday.

Replacement of the 286-mile-long line that runs from Griffith, Ind., to Sarnia, Ontario, is part of a $2.6 billion project to boost the flow of oil to refineries in the eastern U.S. and Canada through a network of pipelines that extends through portions of Michigan and other Great Lakes states.

Some parts of the line have been replaced since the leak in July 2010 spilled more than 800,000 gallons of crude into the Kalamazoo River and a tributary called Talmadge Creek near Marshall, about 70 miles southeast of Grand Rapids. When completed, the pipeline's capacity will be 500,000 barrels per day, more than double the present daily maximum of 230,000 barrels.

"This is very much needed infrastructure," said Stephen Wuori, Enbridge's president for liquid pipelines. "It's what brings us our gasoline, diesel fuel and jet fuel. It will bring jobs to communities along the routes of these pipelines."

The project will need approval from the Michigan Public Service Commission, which has scheduled a hearing for June 6, spokeswoman Judy Palnau said.

Environmental groups said the pipeline shouldn't be expanded until the National Transportation Safety Board completes an investigation into what caused the Michigan leak.

They contend the project would increase the Great Lakes region's vulnerability to pollution from oil developed from giant tar sand deposits in the Canadian province of Alberta, where Enbridge is based. Large volumes of water and energy are needed to separate the sticky, tar-like form of petroleum from the sand. Environmentalists say the substance is dirtier, more toxic and more corrosive to pipes than conventional oil.

"This project needs to be sidelined until there's a better understanding of what's going through the lines," said Beth Wallace of the National Wildlife Federation's Great Lakes office in Ann Arbor.

Legislation enacted by Congress in January called for an investigation of whether tar sands oil, also known as diluted bitumen, poses a greater risk of leaks. The National Academy of Sciences is looking into the matter.

Wuori said there is "no substance to the notion that this oil is different than any other crude or that it's different on pipeline systems than any other type of oil."

Some of the oil transported through the pipeline network is light crude from Canadian tar sands and the rest is being developed from Bakken shale in booming North Dakota, which has become the second-leading oil producing state after Texas, Wuori said.

The Griffith-to-Sarnia line connects with another that serves refineries in Detroit and Toledo, Ohio, that are growing and need more volume of oil, he said.

Enbridge earlier announced plans to expand another pipeline that runs from Superior, Wis., to Sarnia, crossing the Upper Peninsula and the Straits of Mackinac. The company said this week it will reverse the flow of other lines to carry more oil to the eastern refineries.