Information Summary:

Supplemental Notice of Proposed Rulemaking on Best Available Retrofit Technology 

Determination (BART) for Four Corners Power Plant (FCPP)

Today’s Action: 

Today, EPA is issuing a Supplemental Notice seeking comment on an alternative to the 

original October 2010 BART proposal for the Four Corners Power Plant. EPA proposed 

action on the FCPP in order to improve visibility in the nearby national parks and wilderness 

areas and to protect public health. FCPP is located on the Navajo Nation tribal land near 

Farmington, New Mexico. 

Today’s proposal would allow FCPP to close units 1, 2, and 3, the three older and dirtier 

units, by 2014 and install selective catalytic reduction (SCR) technology to reduce emissions 

of nitrogen oxides (NOx) on units 4 and 5 by 2018. 

If FCPP cannot secure the lease agreements or regulatory approvals needed to implement the 

alternative proposal, EPA is proposing to require FCPP to comply with EPA’s BART 

determination, as finalized. 

Proposal Comparisons: 

Today’s proposal would reduce emissions of NOx from 45,000 tons by 87%, to less than 

6000 tons per year (tpy). 

The October 2010 proposal would reduce emissions of NOx from 45,000 tons by 80%, to 

about 9000 tpy. 

Today’s proposal would reduce visibility impacts of the Four Corners Power Plant by 72 % on 

the 16 wilderness areas and national parks. 

The October 2010 proposal would reduce visibility impacts of the Four Corners Power Plant 

by 57% on the 16 wilderness areas and national parks.

Today’s proposal would meet an emission limit of 0.098 lb/MMBtu (million BTU). 

The October 2010 proposal would meet an emission limit of 0.11 lb/MMBtu. 

Today’s proposal will not result in any layoffs, according to the FCPP owners. 

The October 2010 proposal could have resulted in layoffs, according to the FCPP owners. 

Today’s proposal would cost less to implement than the October 2010 proposal. 
Background: 

FCPP is the largest source of NOx in the country. NOx and particulate emissions from the 

Four Corners Power Plant contribute to reduced visibility at 16 nearby national parks and 

wilderness areas, including Mesa Verde. 

Visibility is important to tourism and the economic vitality of the state, local and tribal 

communities. 

Visible haze is related to nearly every other air pollution issue because the same emissions 

that cause haze affect public health, damage forest and crops, harm buildings and vehicles, 

and contaminate lakes and streams. 

Public Participation: 

EPA is requesting comment on the Supplemental proposal to allow APS the option to close 

Units 1 – 3 by 2014 and install SCR on Units 4 and 5 by 2018, in lieu of complying with our 

BART proposal requiring SCR on Units 1 – 5 and new PM controls on Units 1 – 3. 

The comment period on both the original October 2010 proposal and today’s alternative 

proposal will close on May 2, 2011. 

EPA will also provide four opportunities for the public to engage. During the week of March 

28, 2011 interested members of the public may attend open houses with EPA officials. Each 

open house will be followed by an official hearing. These events will take place in the Four 

Corners area: one in Shiprock, on the Navajo Nation, one in Fruitland, on the Navajo Nation, 

one in Farmington, NM, and one in Durango, Colorado. For more details, please visit: 

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