Tear gas, freezing cold water and rubber bullets were used to disperse a crowd of 400 protesters at the Dakota Access Pipeline in clashes late Sunday and early Monday that left more than 150 activists and one law enforcement officer injured.
Linda Black Elk, a member of the Standing Rock Medic and Healer Council of the Catawba tribe, said she treated protesters for injuries and hypothermia and they were soaked by water in temperatures as low as 23 degrees.
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"Last night was a really critical life or death situation," she told NBC News Monday. "There were hundreds of people out on the frontlines. People were first soaked down with tear gas and then sprayed with a bunch of water."
Standing Rock Sioux Chairman Dave Archambault II told NBC News that between 200-300 people were transported late Sunday night to a gymnasium on the Standing Rock Sioux reservation for treatment for hypothermia, facial and hand wounds, and other minor injuries. Approximately seven people with more serious injuries — including two elders who were tear gassed and who suffered near cardiac arrest — were sent to a hospital in Bismark for emergency treatment, said Archambault.
He said the tribe was reaching out to the White House Monday with a request that the Obama administration intervene "due to the threat to public safety at Standing Rock."
"From the beginning, we've had water protectors attacked by guard dogs, rubber bullets and mace. Last night, law enforcement upped the ante by using exploding tear gas canisters and water cannons in sub-freezing temperatures," said Archambault. "There's no telling what law enforcement will do next."
Protestors say that the clashes began when they tried to remove a roadblock on a bridge north of their Oceti Sakowin "Water Protector" Camp. The roadblock, composed in part of burned-out trucks, has blocked the main route to the city of Bismarck since late October.
"The negotiation from law enforcement stated that they were going to remove them for their emergency services to get through ... to Bismarck. It's been 2.5 weeks, maybe 3, and they still haven't kept their word on that," said E'sha Hoferer,who live-streamed the clashes on Facebook.
Black Elk said the roadblock was an inconvenience and posed a risk for emergency personnel trying to access the protest camp.