We’re now learning oil from last week’s Exxon Mobil pipeline rupture under Montana’s Yellowstone River has traveled much further downstream than the oil giant originally estimated. Reports now say the oil has traveled at least 15 miles down the river. The Billings Gazette reports hundreds of workers are now involved in the cleanup effort:

Monday afternoon, much of the cleanup efforts were concentrated on the Thiel Road area east of Laurel, where gobs of black crude cover much of the riverbank, sticking to the tall grass and low-hanging tree limbs. Swirls of red-brown oil sit in pools of standing river water next to the road. Dozens of white-clad cleanup crews were there, scooping up sticky oil-covered river debris and placing it in black trash bags. Booms and pads were sitting in the water catching oil as it floated in the current. A small crew at Mystic Park was on hands and knees wiping oil from clumps of grass where the river had receded.

The sad reality is that much of the oil will be impossible to “clean.” As I learned when I visited Louisiana in April, a full year after the Gulf oil disaster began and despite the work of an army of BP contractors, it’s not hard to find oil still fouling coastal wetlands.

While Exxon Mobil has been eager to talk to the press, they’ve been less forthcoming with Montana residents. The National Wildlife Federation’s Alexis Bonogofsky lives on the Yellowstone River and her farm’s pasture, already flooded by high river water, is now coated in oil. Alexis says that while elected officials were allowed into a news conference on Sunday, she and her husband Mike were shut out. Yesterday, Mike returned to look for answers while Alexis was treated for oil exposure:

After the news conference, Pruessing was confronted by an angry goat farmer and environmental activist who said his wife had been sickened by oil fumes and had to be taken to the emergency room. “I need to know what we’ve been exposed to. People are sick now,” said Mike Scott, who also works for the Sierra Club. Scott said his wife, Alexis Bonogofsky, was diagnosed Monday with acute hydrocarbon exposure after experiencing dizziness, nausea and trouble breathing. Bonogofsky, who works for the National Wildlife Federation, had gone to the riverbank with her camera to photograph oil on their property south of Billings.

Alexis is home now, but it’s a reminder of how dangerous oil can be and the risks of approaching it without full protective gear. You can get more updates from Alexis by following @ABonogofsky on Twitter.

Including the Gulf oil disaster and Michigan’s Kalamazoo River oil spill, the Yellowstone River spill becomes America’s third major oil disaster in just the last 15 months. As the National Wildlife Federation has documented, oil and gas disasters are tragically common.

Now the oil industry wants to build a new pipeline crossing through Montana, South Dakota, Nebraska, Kansas, Oklahoma and Texas. The Keystone XL pipeline would carry tar sands, one of the dirtiest fuels on the planet.

The Obama administration hasn’t yet given final approval to the pipeline, which means we still have a chance to protect our public water supplies, crop lands, wildlife habitats. Please take a moment right now to ask President Obama to say no to tar sands.