– The State Department will give the public more time to comment on the Keystone XL pipeline, which could delay the final decision on a project that has been under review for more than five years.

The department is completing a final environmental assessment of the proposed pipeline to carry oil sands crude from Canada to refineries along the Gulf of Mexico.

When that is released, State Department officials will start a process to determine whether TransCanada Corp.’s $5.4 billion project is in the national interest before President Obama’s final decision.

Canadian Prime Minister Stephen Harper is a strong proponent of the pipeline, a key part of the country’s plans to find new markets for its oil.

The Canadian government “has to be concerned about the erosion of approval in Canada, not just in terms of its impact in Canada but also in terms of the U.S.,” said Nik Nanos, president of Nanos Research and global fellow at the Woodrow Wilson International Center.

The State Department will seek public comment during the national interest determination review period, according to the official, who requested anonymity. The agency didn’t specify an amount of time.

For many, Keystone has become a barometer of Obama’s commitment to addressing climate change.Labor unions and many Republicans in Congress back the project to help create jobs and expand the U.S. economy.

The State Department held a hearing and accepted comments for the environmental study. Once it is complete, federal agencies will have 90 days to submit comments on the project.