The Canadian company that wants to build the disputed Keystone XL pipeline in the US submitted a new application for the project on Friday after changing the route to avoid environmentally sensitive land in Nebraska.
TransCanada said it applied again to the State Department for permission to build the pipeline to carry oil from so-called tar sands in western Canada to a company hub in Steele City, Nebraska. From there, the project would link up with other pipelines operated by the company to carry oil to refineries on the Texas Gulf Coast.
President Barack Obama blocked the pipeline earlier this year, citing uncertainty over the Nebraska route - a decision that drew fire from Republicans. TransCanada initially proposed a new route last month that would veer east around the groundwater-rich Sandhills region before looping back to the original route.
State Department approval is needed because the 7 billion US dollars (£4.3 billion) pipeline would cross a US border. The department confirmed on Friday the application for the new route had been received.
Mr Obama is under pressure to support the pipeline from Republicans and business and labour leaders who argue it would create jobs; the State Department estimates it could result in up to 6,000 new jobs.
"The multi-billion dollar Keystone XL pipeline project will reduce the United States' dependence on foreign oil and support job growth by putting thousands of Americans to work," said Russ Girling, TransCanada's president and chief executive officer. "Our application for a presidential permit builds on more than three years of environmental review already conducted for Keystone XL," Girling added.
The pipeline's opponents, including Democrats and environmental groups, say it would transport "dirty oil" from tar sands in Alberta, Canada, that would require huge amounts of energy to extract. They also worry about a possible spill. The pipeline would travel through Montana, South Dakota, Kansas and Oklahoma, in addition to Nebraska.
In blocking the pipeline in January, Mr Obama said there was not enough time for a fair review before a looming deadline forced on him by congressional Republicans. The action did not kill the project but put off a tough choice on the once-obscure pipeline, which has become a flashpoint in the bitter partisan political fight over jobs and the environment and a focus of the presidential campaign between Mr Obama and his likely Republican opponent, Mitt Romney.
Nebraska Governor Dave Heineman signed a Bill last month that allows the state to proceed with its review of the proposed pipeline through his state, regardless of what happens at the federal level.
A senior State Department source said US officials would conduct a thorough review of the new application, with a final decision not expected until early next year - well after the presidential election.