(CNN) - Van Jones, a former green jobs official in the Obama administration and a CNN contributor, said Friday that if the controversial Keystone oil pipeline is constructed under President Barack Obama's watch, it could become part of his legacy.
"Now it's the 'Obama Pipeline' and it leaks," he said, posing the hypothetical situation of a spill along its 1,700-mile length.
"His legacy could be the worst oil disaster in American farmland history. He's got to make a tough choice," Jones said.
A required State Department report on Friday said the "construction and normal operation" of the latest proposed route would have no significant environmental effect.
The State Department assessment is necessary because the route crosses an international border - from Canada into the north-central United States.
Environmental advocates, however, see it differently, as does Jones, who was a special adviser to Obama on the topics of green jobs, enterprise, and innovation at the Council on Environmental Quality.
"This is a shockwave going through the environmental community right now, the scientific community right now," he said.
The reason is that tar sands, a particularly raw form of oil, would be traveling through the pipeline, and Jones described it as "the most corrosive nasty fuel on the Earth."
The Obama administration previously delayed the project by turning down a prior route proposal from oil company TransCanada. Republicans, including 2012 GOP presidential nominee Mitt Romney, have hammered him over the issue.
"And with respect to this pipeline that Governor Romney keeps on talking about, we've built enough pipeline to wrap around the entire Earth once," Obama said at a presidential debate last fall. "So I'm all for pipelines. I'm all for oil production. What I'm not for is us ignoring the other half of the equation," including green energies, Obama said.
Jones said several "myths" exist about the Keystone pipeline - including the number of jobs it would create and the amount of oil it would mean for U.S. consumption.
"It's going through the United States to China," he said of the oil, which would be processed in facilities along the Gulf Coast. "We won't get a drop of it. So we risk our water, risk our farmland and get no oil - bad deal for America."