National Public Radio, through a series of Freedom of Information Act requests, found the Environmental Protection Agency is letting oil companies release wastewater on tribal lands that could contain potentially toxic chemicals associated with oil drilling.
State regulators governing wastewater on their land use rules the broadcaster reports are stricter than what the EPA is using on tribal lands. Wes Martel, vice chairman of a tribal government in Wyoming, told the broadcaster the situation with wastewater there doesn't "look too cool."
Outside of tribal areas, most wastewater is injected underground. Environmental records from tribal regulators, NPR reports, found "toxic levels" of some chemicals, dead animals and elevated water temperatures associated with water sampled downstream from some oil fields.
Bob Whisonant, a regional manager for Marathon Oil, told the broadcaster that water quality was within EPA requirements.
"As far as I know, there has never been concerns and opposition for the quality of the water that I'm aware about," he said. Some ranchers in the area also brushed off quality concerns.
The EPA didn't speak directly to the broadcaster but offered a statement saying it was planning to meet with tribal governments "in upcoming weeks to discuss next steps."