From NPR: A bizarre exception to EPA regulations allows oil companies to dump their wastewater at the surface rather than reinjecting it into another well, which is the typical method of disposal.  Wyoming ranchers argued in the 1970s that banning these oil companies from dumping their wastewater would harm livestock and wildlife that rely on this dirty water for survival (a claim that continues to this day).  Most states have enacted and enforce toxic waste disposal laws more strict than the EPA; however the state does not have jurisdiction over the reservation and it is up to the EPA.  They interviewed my acquaintance, Dr. Rob Jackson at Duke University, for expert opinion on the science of this issue.
Read or listen to this news story on NPR’s “All Things Considered” here.