The State Department opened its draft environmental review up for public comment earlier this year. It said it published about 100,000 of the 1.2 million received, a first for a project of its kind.
Pipeline company TransCanada aims to build Keystone XL to deliver Canadian crude oil through the United States to Gulf Coast refineries.
The U.S. House of Representatives sent a bill to the Senate that removes the decision from U.S. President Barack Obama's hands, saying it's been vetted enough. A presidential permit is required for pipeline because it would cross international borders. Obama said he'd veto the House measure if it passes the Senate, which is unlikely.
Supporters of the project say it would help ensure North American energy sector and stimulate the regional economy. Opponents expressed concern because pipelines carrying Canadian crude oil seem more prone to spills.
The State Department's draft review said environmental effects of Canadian crude oil production, seen as carbon intensive, would be prevalent with or without the pipeline. It added that existing rail infrastructure should be considered when weighing the project's national interest.
"The department decided to post these comments as part of its continued effort to maximize transparency in the federal presidential permit review process," it said.
More publications are expected weekly.