Many tribe members believe the coal ash has caused asthma attacks, cancer, heart disease and even some premature deaths among the 200 residents living here. They've noticed these illnesses since the 1980s, and can't point to an exact number of deaths linked to the plant. But Vicki Simmons, who sits on the tribe’s environmental committee, said it includes her brother.

“My brother worked down at that plant. He was 31 years old when he passed away,” said Simmons, who heads air quality testing for the reservation. “I just realized how many sick people there are — people I work with, my neighbors and the people that live next to them. So it started having a pattern to me.”

A small hill overlooks the tribe's cemetery, which sits next to the power station.

“Whoever could speak, they did. A lot of those people are dead, or now they're ill,” Simmons added as she stood on the hill. “People are just dropping like flies.”