For many decades after they were forced onto reservations in the late 1800s, Native American tribes had virtually no control over their land and environment.

But today, 15 of the more than 500 tribes in the United States run their own air-quality programs under the federal Clean Air Act. Twenty tribes run water-quality programs approved by the Environmental Protection Agency, under the Clean Water Act. And more tribes are in the process of establishing their own enforcement programs.

Congress created the environmental laws in the early 1970s, to establish national air and water quality standards and regulate pollutants. Both laws at first ignored the tribes, and empowered only the federal government and states.

But Congress has amended the laws, allowing tribes to apply for similar status as state governments — what’s known as TAS, which stands for Treatment As State. To win this status, a tribe must clear a series of hurdles and be judged “reasonably” capable of consistently administering an environmental program. Then a tribe can monitor and enforce its own air and water standards, issue permits and wield subpoena and investigative powers over any potential polluter on the reservation.

Establishing a tribal program takes money, expertise and years of work, typically with assistance from the EPA. Only four other tribes have successfully classified themselves as “Class I airsheds” — which puts them on par with national parks and wilderness areas — since the Northern Cheyenne reached that milestone in 1977: the Confederated Salish and Kootenai Tribes on the Flathead Reservation in northwest Montana; the Sioux and Assiniboine tribes on the Fort Peck Reservation in northeast Montana; the Yavapai-Apache on the Camp Verde Reservation, Arizona; and the Spokane Reservation in Washington.

Other tribes with top air and water programs include the Gila River Tribe in Arizona, the Navajo, the Yakama in Washington, and the Isleta Pueblo near Albuquerque (HCN, 2/2/98: A tiny tribe wins big on clean water).