I haven't followed the ins and outs of this, since, well, I really don't care. Everybody has a different story about whether the pipeline is really on Indian land or just close to it and an affront to their ability to control stuff they don't actually control by playing the 'Cultural significance' card.
However, I am laughing at all the 'Chemical warfare against our water' crap they've been flinging lately. Hey, remember how the Alaska pipeline ruined all the ground water there, or how Louisiana became a poisoned wasteland? What? You mean that didn't happen? But...but...