Energy giant TransCanada is suing the United States for canceling the controversial Keystone XL oil pipeline.
TransCanada filed its suit Friday, saying it was seeking $15 billion to recover costs and other losses. It announced its intention to sue in January, but said it wanted to give arbitration a chance first. The company said it was unable to reach an "amicable settlement" with the U.S.
TranCanada sued under provisions in the North American Free Trade Agreement that aim to protect foreign investors.
The Keystone XL was to have carried crude oil from western Canada's tar sands oil fields to U.S. refineries along the Gulf of Mexico. President Barack Obama stopped the project last year, saying it was not in the U.S. national interest to build a huge fossil-fuel related project while at the same time leading the fight against global warming.
Conservatives and other critics blasted the president, saying the project would have created thousands of jobs.
Environmentalists say crude oil from tar sands is incredibly dirty and a spill from the pipeline could have been a catastrophe.