Many risks are posed by by the KXL pipeline for First Nation people. On top of water pollution and numerous other environmental dangers, these people may face the damage or destruction of sacred and/or historically significant sites/structures- 93 in total. Moreover, the risks of water pollution include cancer- many kinds of cancer including some very rare types such as bile duct cancer.
First Nation people have faced immense difficulties throughout history as they try to preserve a nature-oriented spirituality in an increasingly industrial society. In a day and age where every American is encouraged to stand up for their right to be able to practice their own individual religions, this is more than a matter of the environment, or even of the price of oil.
This is a matter of morality.