WASHINGTON - The State Department announced Friday that construction of the Keystone XL Pipeline is unlikely to have a significant impact on climate change, a finding that could open the door for President Obama to approve the controversial project.

The 1,700-mile pipeline would bring oil from the Alberta oil sands in Canada to U.S. refineries on the Gulf Coast. The Congressional Research Service has estimated that crude oil from the sands could produce 14 percent to 20 percent more planet-warming gases than the average oil in U.S. refineries.

But the State Department said Friday that denying the pipeline wouldn't stop the Canadian oil from getting to market by rail or construction of other new pipelines.

"Approval or denial of any one crude oil transport project, including the proposed project, remains unlikely to significantly impact the rate of extraction in the oil sands," according to the State Department's environmental analysis.

Environmental groups expressed outrage at the finding. They said the oil industry wouldn't have spent millions lobbying for the $7 billion Keystone pipeline if it weren't important for developing the oil sands.

Keystone is fundamental to the industry's plan to triple production in the sands, said Danielle Droitsch, project director for the Natural Resources Defense Council. The pipeline will produce the equivalent of putting 6 million new cars on the road, Droitsch said.

"It is a total myth that tar sands expansion will continue to grow even if Keystone XL were rejected," she said. "It is not in the public's best interest to expand America's dependence on tar sands. It undermines our effort to move to clean energy and fight climate change."

Industry groups said the State Department's analysis confirms it is time to stop delaying the pipeline.

"The Keystone XL project has become one of the most closely examined infrastructure projects in our nation's history, and it continues to pass with flying colors," said Chamber of Commerce energy spokeswoman Karen Harbert. "Once again, the State Department has confirmed that this project is environmentally sound."

It's not a done deal. There will be a 45-day comment period after the State Department's analysis is formally published in about a week. Then the State Department will review the comments and create a final environmental impact statement for the pipeline project.

At that point, the State Department will decide whether the project is in the national interest and will ask other agencies their views on whether it should go ahead.

Obama has made clear he'll have final say on the pipeline.