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Permit Request On February 20, 2015, EPA Regio n 9 received an application from Salt River Project Agricultural Improvement and P ow er District (SRP) requesting a m inor NSR permit for the Navajo Generating Station (NGS) in accordance the requirements of the Tribal Minor NSR permitting program at 40 CFR Part 49.151

- 161. The NGS is a facility with three existing coal fired electricity generating unit s (EGU s ) located within the exterior boundaries of the Navajo Nation Indian Reservation in the northern part of the State of Arizona near the town of Page. The facility location is given below:

Sec 2 T40N R9 E

Latitude: 36

. 903135 N Longitude:

- 111.390242 W Coconino County , Arizona

The proposed minor NSR permit would authorize SRP to construct and operate a refined coal treatment system (RCTS), including ancillary equipment, in order to treat coal with cement

kiln dust and calcium bromide prior to combustion in existing boiler units 1, 2, and 3 . The proposed permit for the RCTS Project would result in increases in emissions of particulate matter (PM, PM 10 , and PM 2.5 )

. Increases in particulate matter emissions will originate primarily from increased truck delivery traffic on existing unpaved roads at NGS . There will also be some particulate matter emissions increases from new dust collectors to be installed on the RTCS conveyor belt systems and new baghouses associated with cement kiln dust storage silos and day

bins

. A very small increase in emissions will originate from the existing Units 1, 2 and 3 due to

the increased ash content of the coal , however, this increase will not result in changing the permitted emissions limits for the EGUs

. Air pollution emissions from the RCTS Proj ect are below Prevention of Significant Deterioration ( PSD ) thresholds and will not cause or contribute to violations of any National Ambient Air Quality Standards (NAAQS).

The existing PSD permit issued to SRP in 2008 for the installation of a Low

- NOx b urner project at NGS (see PSD Permit No. AZ 8

- 01A), is being amended under this action to incorporate the minor NSR permit conditions, including operational standards and recordkeeping requirements for cement kiln dust and calcium bromide deliveries

, as we ll as testing and recordkeeping requirements for new equipment to be installed under the RCTS project. There are no changes in any established emission limits for the existing boiler units 1, 2, and 3.

Air Quality Review

The Tribal Minor NSR regulations at 40 CFR 49.154(d) require that an Air Quality Impact Assessment (AQIA) modeling analysis be performed if there is reason to ensure that new construction will not cause or contribute to a NAAQS or PSD increment violation. If an AQIA reveals that the propo sed construction could cause or contrib ute to a NAAQS or PSD increment violation, such impacts must be addressed before a pre

- construction permit can be issued.

For purposes of Executive Order 12898 on environmental justice, the EPA has recognized that c ompliance with the NAAQS is “emblematic of achieving a level of public health protection that, based on the level of protection afforded by a primary NAAQS, demonstrates that minority or low

- income populations will not experience disproportionately high an d adverse human health or environmental effects due to the exposure to relevant criteria3

pollutants.” In re Shell Gulf of Mexico, Inc. & Shell Offshore, Inc

. , 15 E.A.D. 103, 156 (EAB 2010). This is because the NAAQS are health

- based standards, designed to protect public health with an adequate margin of safety, including sensitive populations such as children, the elderly,

and asthmatics.

The proposed RCTS Project at NGS will result in increased emissions of PM, PM 10 , and

PM 2.5 . Although all emission increases due to the proposed project are below PSD thresholds

, increases in PM and PM 10 exceed minor NSR permitting thresholds. An analysis for PM is not required because there is no longer a NAAQS for PM. A primary and secondary NAAQS exists

for PM 10 , th erefore , impacts due to PM 10 are being analyzed to ensure that they do not contribute or cause any impacts on the annual and 24

- hour PM 10 NAAQS or a PSD increment violation

. SRP conducted a PM 10 and PM 2.5 modeling analysis for the R CTS Project to determine the impact of emissions increases on the annual and 24

- hour PM 10 and PM 2.5 NAAQS

. Although an analysis is not required for PM 2.5 , SRP submitted a modeling report for PM 2.5 to demonstrate that

PM 2.5 emissions from the RCTS project a re not expected to exceed the minor NSR threshold. The modeling showed that maximum concentrations of PM 10 and PM 2.5 occur within the existing facility boundary and that i ncreases of these pollutants do not exceed the Significant Impact Levels ( SILs ) outside the facility boundary and do not result in ambient concentrations that

exceed the NAAQS. Therefore, due to the fact that the emissions beyond the facility boundary are insignificant, we are proposing to grant the mi nor NSR permit because the construction and operation of the proposed RCTS project will not have any adverse effect on ambient air quality

.

Environmental Impacts to Potentially Overburdened Communities

This m inor NSR permit action authorizes the construction of new equipment and changes in operational standards which will cause an increase in air emissions of particulate matter at the NGS facility . The increased air emissions at the existing facility will not contribute to or cause any violation of the NAAQS. All emissions due to the RTCS P roject will be well controlled at all

times and subject to federally enforceable permit conditions . This permit action will have no adverse ambient air quality impacts.

Furthermore, the existing PSD permit that was issued in 2008 contains provisions stating,

“ At all times, including periods of startup, shutdown and malfunction, Permittee shall, to the extent practicable, maintain and operate the facility including associated air pollution control equipment in a manner consistent with good air pollution control practices for minimizing

emissions

, ” and “ Permittee shall construct and operate this project in compliance with this PSD Permit, the application on which this Permit is based, and all other a pplicable federal, state, and local air quality regulations. This PSD Permit does not release the Permittee from any liability for compliance with other applicable federal, state and local environmental laws and regulations, including the Clean Air Act. ” N oncompliance with these permit provisions is a violation of the permit and is grounds for enforcement action and for permit termination or revocation. As a result, the EPA concludes that proposed issuance of this m inor NSR permit and incorporating its cond itions into the existing PSD permit will not have disproportionately high or

adverse human health effects on communities in the vicinity of the Navajo Nation Indian

Reservation.

A report made using EPA’s EJSCREEN tool showing demographics based on the U.S. Census

Bureau 2010 data in the area surrounding the NGS facility is attached to this memorandum.4

Public Participation Given the presence of potentially overburdened communities in the vicinity of the NGS facility, we are providing an enhanced public participation process for this permit. 1. The minor source permit application was submitted to both the EPA and the Navajo Nation

EPA per the application instructions (see http://www3.epa.gov/air/tribal/tribalnsr.html ).

2. Navajo Nation EPA ha d 10 business days to communicate to us any preliminary questions and comments on the application.

3. In the event an Air Quality Impact Analysis is necessary in addition to the initial application

,

we typically email a copy of that document to Navajo Natio n EPA within 5 business days from

the date we receive it. This step was not necessary because t he applicant has attached the Air Quality Impact Analysis to the application and submitted it to Navajo Nation EPA.

4. We are notify ing Navajo Nation EPA , ot her affected states and tribes, and other interested parties of the public comment period for the proposed minor NSR permit and provid ing copies of the notice of public comment opportunity to post in various locations on and around the

Reservation. We will also notify Navajo Nation EPA

, other affected states and tribes, and other interested parties, of the issuance of the final permit.

Attachment s (1) EJSCREEN Census 2010 Summary Report

– Area within an 9

- mile radius of Navajo Generating Station (2) EJ S CREEN Report of area within an 9

- mile radius of Navajo Generating Station