The U.S. State Department said Friday a challenge to a state law giving Nebraska Gov. Dave Heineman authority over the pipeline's route and the more than 2.5 million public comments meant more time was needed for review.
TransCanada submitted an application for the the cross-border Keystone XL more than five years ago. Supporters say the pipeline will be a source of economic stimulus and add a layer of security to the North American energy sector. Opponents have expressed concern about the environmental harm from the exploitation of Canada's heavier form of crude oil.
Terry O’Sullivan, general president of the Laborers’ International Union of North America, said the delay was a "gutless move" from the Obama administration.
"This is another low blow to the working men and women of our country for whom the Keystone XL pipeline is a lifeline to good jobs and energy security," he said in a statement Friday.
Stephen Kretzmann, executive director of Oil Change International, said the North American energy sector is rich enough with oil that another pipeline isn't needed.
"America has more than enough oil -- what is needed now is far greater investment in clean energy and the political will to stand up to Big Oil," he said.
[Oil Change International]
2014: The Year in Music [PHOTOS]