Updated

UN Ambassador Susan Rice, already under fire from Republicans, is now taking hits from the left over six-figure investments in the company behind a controversial oil pipeline.

Rice, rumored to be on the short list to replace Hillary Clinton as Secretary of State, owns between $300,000 and $600,000 in TransCanada Corp. stock, according to the TheHill.com, which cites Rice's financial disclosure forms. TransCanada is the company whose 1,700-mile Keystone XL pipeline, which would bring oil from Canada down to Gulf refineries has been repeatedly delayed and now is in regulatory limbo.

The liberal group RootsAction.org, has started an online petition demanding that Rice "immediately sell every dollar of stock" in the company behind the $7 billion project. Environmentalists say the pipeline would pollute air and water supplies as well as harm fragile ecosystems. Energy industry officials argue that the Keystone XL would be no different from an extensive network of energy pipelines already in place – and some say its state-of-the-art design would make it safer than many of the country’s aging pipelines.

The State Department would have to sign off on the pipeline because it spans the border between the U.S. and Canada

"It's indefensible that Susan Rice has millions of dollars invested in oil companies and banks that will make huge profits if the State Department gives approval to the XL pipeline," the group says in a statement online.

The website, OnEarth.org, published a story Wednesday on Rice's reported investments in more than a dozen Canadian oil companies and banks that would stand to benefit from the pipeline.

"It’s really amazing that they’re considering someone for Secretary of State who has millions invested in these companies,” Bill McKibben, a writer and founder of the activist groups 350.org and Tar Sands Action, told the website. "The State Department has been rife with collusion with the Canadian pipeline builders, and it’s really distressing to have any sense that that might continue to go on."