Arizona Public Service Company officially announced yesterday that it will retire Units 1, 2, and 3 of the Four Corners Power Plant by January 1, 2014 and install long-overdue pollution controls on the plant’s remaining two units by July 31, 2018.

Built before the Clean Air Act was enacted, this coal plant has been operating without modern pollution controls for the past fifty years. Uncontrolled pollution from this plant threatens the health of its Navajo neighbors and mars visibility in surrounding national parks, including the iconic Grand Canyon. Retirement of three of the plant’s units is an important step forward for environmental justice, protection of public lands, and our ongoing struggle against climate change.

Our ability to leverage an interesting interplay of state and federal environmental laws served a key role in yesterday’s announcement. Federal requirements to eliminate manmade haze pollution in our national park and wilderness areas targeted coal plants as primary culprits of pollution that affects our ability to enjoy the beautiful scenery of these parks. And, even among these culprits, Four Corners has the greatest visibility impact on these pristine areas of any coal plant in the country, according to the National Park Service.

Earthjustice weighed in on EPA’s haze regulation of the plant, helping to secure state-of-the art pollution controls on the plant’s largest two units. Meanwhile, California’s greenhouse gas requirements (SB 1368), which prevent California utilities from making long-term investments in coal-fired electricity generation, motivated Southern California Edison Company to sell its share of the plant to its co-owner, Arizona Public Service Company. Here, too, Earthjustice actively participated in California Public Utilities Commission proceedings to ensure SoCal Edison’s timely exit from the plant with minimal ongoing investment. The sale, in turn, allowed APS retire Units 1–3.

But our work is not yet complete. We are representing local environmental justice groups along with national conservation groups in ongoing Clean Air Act enforcement against the owners of the plant. And while we take a moment to acknowledge the environmental gains from yesterday’s announcement, a push continues for additional pollution reductions to support a just transition to a clean energy future in the Southwest.

Earthjustice will continue that push in 2014 and beyond, on behalf of our clients—the National Parks Conservation Association (NPCA), Sierra Club, Diné CARE, and To’ Nizhoni Ani—in ongoing Clean Air Act litigation against the Four Corners power plant.