The Standing Rock Sioux tribe believes that the pipeline would put the Missouri River , the water source for the reservation , at risk . They pointed out two recent spills , a 2010 pipeline spill into the Kalamazoo River in Michigan , which cost over billion to clean up with significant contamination remaining , and a 2015 Bakken crude oil spill into the Yellowstone River in Montana . The Tribe was also concerned that the pipeline route may run through sacred Sioux sites . In August 2016 protests were held , halting a portion of the pipeline near Cannon Ball , North Dakota . Peaceful protests continued and drew indigenous people from throughout North America , as well as other supporters . A number of planned arrests occurred when people locked themselves to heavy machinery
a 2010 pipeline spill into the Kalamazoo River
Kalamazoo River oil spill
Dakota Access Pipeline protests