Located on the Navajo Nation outside Page, Arizona, and less than 20 miles from the Grand Canyon, the coal-fired power plant was constructed in the mid-1970s.
NGS is owned by several entities, including the Bureau of Reclamation, Arizona Public Service, Tucson Electric Project and Salt River Project, which also operates the facility.
The Los Angeles Department of Water and Power and NV Energy also own part of the plant, but both have revealed plans in 2013 to sell their stakes.
The EPA plan, when fully implemented by 2030, is expected to reduce NOx emissions by approximately 80% and the visual impairment from NGS by about 73% at 11 national parks and wilderness areas.
EPA regional administrator for the Pacific Southwest Jared Blumenfeld said: "By cutting pollution from NGS, millions of visitors will see the magnificent vistas of the Grand Canyon with greater clarity.
"This flexible and practical solution will also generate critical tribal revenues, improve public health, provide long-term certainty to power and water utilities and set the stage for a transition to a clean energy future."
