United States Regional Administrator Region 9, Arizona, California 

Environmental Protection 75 Hawthorne Street Hawaii, Nevada, Guam 

Agency San Francisco, CA 94105-3901 American Samoa, 

Northern Marianas Islands 

For Immediate Release: October 6, 2010

Contact: Margot Perez-Sullivan, (415) 947-4149, perezsullivan.margot@epa.gov

EPA proposes pollution controls for nation’s largest source of NOx: Four Corners Power 

Plant 

Move would reduce 36,000 tons of NOx - equal to taking half gasoline cars and trucks in 

Arizona off the road - improving public health and visibility 

SAN FRANCISCO – Today, the U.S. Environmental Protection Agency proposed requiring 

additional pollution controls for the Four Corners Power Plant located on the Navajo Nation near 

Farmington, New Mexico to improve visibility and human health. EPA’s proposal will require 

plant operators to install the most stringent pollution control technology available for this type of 

facility. These controls will reduce emissions of nitrogen oxides (NOx) from approximately 

45,000 tons per year to 9,000 tons per year. 

Every year over 280 million people visit our nation’s most treasured parks and wilderness areas. 

Yet, many visitors aren’t able to see the spectacular vistas because of the veil of white or brown 

haze that hangs in the air, reducing visibility and dulling the natural beauty. There are 16 

national parks and wilderness areas in the vicinity of the Four Corners Power Plant, including the 

Mesa Verde and the Petrified Forest. These controls are estimated to reduce the visibility impact 

by an average of 57% at these areas. 

In addition to reducing visibility, nitrogen oxides (NOx) react with other chemicals to form 

ozone and small particles, both harmful to the public’s health. Ozone forms when nitrogen 

oxides and volatile organic compounds react in the presence of heat and sunlight. Children, the 

elderly, people with lung diseases such as asthma, and people who work or exercise outside are 

at risk for adverse effects from ozone and particulate matter. 

“The Four Corners Power Plant is the largest source of nitrogen oxides in the nation,” said Jared 

Blumenfeld, EPA’s Regional Administrator for the Pacific Southwest Region. “Adding new 

pollution controls at this 45-year old plant will reduce these emissions by 80%—we will all be 

able to see the results and breathe cleaner, healthier air.” 

The Clean Air Act’s Regional Haze Rule requires the use of Best Available Retrofit Technology 

at older coal-fired power plants to reduce haze and improve visibility. EPA’s proposal is 

achievable by installing and operating Selective Catalytic Reduction on all five units at the plant. 

The installation and operation of SCR is estimated to increase the electricity bill for the average 

Arizona Public Service residential customer by about 70 cents per week. 
SCR is cost effective technology that will result in the greatest visibility improvement of all 

devices the agency considered. When the proposal is finalized, the Four Corners Power Plant 

will have five years to add the controls. 

EPA will continue to consult with the Navajo Nation and other affected tribes, and the Federal 

Land Managers before taking any final action. There will be a 60-day public comment period on 

the proposed action as well as two public hearings in the Four Corners area. 

For additional information on the proposed rulemaking and opportunities to provide input, please 

go to: http://www.epa.gov/region9/air/navajo/index.html#proposed