### June 26 , 2014

Marcelo Calle

O ffice of Surface Mining Western Region 1999 Broadway, Suite 3320 Denver, Colorado 80202

- 5733

Harrilene Yazzi

Bureau of Indian Affairs Navajo Regional Office

301 West Hill Street

P.O. Box 1060

G allup, N ew M exico 87305

Subject: EPA Comments on the Four Corners Power Plant and Navajo Mine Energy Project Draft

Environmental Impact Statement, Navajo Nation, San Juan County, New Mexico (CEQ # 20140097 )

Dear Mr. Calle:

The U.S. Envir onmental Protection Agency (EPA) has reviewed the above

- referenced document

pursua nt to the National Environmental Policy Act (NEPA), Council on Environmental Quality (CEQ) regulations (40 CFR Parts 1500

- 1508), and our NEPA review authority under Section 309 of the Clean

Air Act. Our detailed comments are enclosed.

The Draft Envir onmental Impact Statement (DEIS) assesses the impacts from the continued operation of

the Four Corners Power Plant (FCPP) , a coal

- fired power plant with a generating capacity of up to 1,500 megawatts (2 units)

, should the Bureau of Indian Affairs (BIA) app rove Arizona Public Service Company’ s proposed lease amendment and application for right

- of

- way renewals for operation through

2041

. The project also involves continued and extended surface coal mining at the Navajo Mine

, should

the Office of Surface Mining (OSM) renew the Navajo Mine’s existing Surface Mining Control and Reclamation Act (SMCRA) permit for 5 years a nd approve an application for a new S MCRA p ermit for

the Pinabete Permit Area. Lastly, the project proposes right

- of

- wa y renewal s by BIA for portions of

four transm ission lines.

EPA is a cooperating agency for the proposed project and provided comments on the Preliminary DEIS

to the OSM and BIA on February 6, 2014. We found the DEIS t o be largely responsive to our

commen ts

, and appreciate the changes made to the document to address them. C omments that were not fully addressed are reiterated in the attached Detailed Comments

. Based on our review of the DEIS , we have rated the Preferred Alternative A a s Environmental Concerns

– Insufficient Information (EC

- 2) (see enclosed “ Summary of Rating Definitions”). Our concerns regard the existing c ontamination of groundwater from coal combustion residue (CCR) disposal and the need for enforceable commitment s regarding future CCR management, monitoring and remediation. We also have concerns regarding the UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION IX

75 Hawthorne Street San Francisco, CA 94105assessmentofcumulativehealthimpactsfromcontinuedoperationoftheproject,giventheseverelycompromisedexistingpublichealthenvironment.PollutantsfromthedisposalofCCRhavecontaminatedgroundwaterattheFCPP.TheDEISincludesanumberofvoluntarymeasurestobetakenbyArizonaPublicService(APS)regardingoperations,design,groundwatermonitoring,correctiveaction,andclosureandpost-closureofCCRdisposalfacilitiesattheFCPP.BecausefutureregulationsbyEPAregardingCCRmanagementmaynotapplyonTriballands,westronglyrecommendthatthevoluntarymeasuresbeincorporatedasconditionsofapprovalbytheBIAintheeventitapprovesAPS’sproposedleaseamendmentandapplicationforrightof-wayrenewals.GroundwatercontaminationfrompastdisposalofCCRinNavajoMinehasalsooccurredandwerecommendmonitoringofgroundwaterattheNavajoMinetoconfirmtheDEISconclusionsthatconstituentsofconcernwouldbeattenuatedasgroundwatertravelstowardstheSanJuanRiverandtheChacoRivers.TheDEISconcludesthatthatcumulativeimpactstopublichealthfromboththeFCPPandtheMinewouldbeminor.EmissionsofsomepollutantsfromthepowerplantwillbereducedasaresultofEPA’sFederalImplementationPlan-BestAvailableRetrofitTechnology,andthesereductionsareexpectedtohaveapositiveimpactonpublichealth.Nevertheless,asdisclosedintheDETS,healthoutcomesforNavajo,intermoflifeexpectancyandmortalityrates,areworsethanforthegeneralpopulationinSanJuanCounty,partlyduetohealthcaredisparities.Thecumulativehealthburdenalsoincludestheimpactsfromin-homeburningofcoalthatisprovidedbytheNavajoMinetolocaltribalmembersfreeoratlow-cost.Thiscoalisoftenburnedinimproperly-ventedstovesnotdesignedtoburncoal.BecausemanyNavajodonothaveaccess,oraffordableaccess,toelectricity,theprovisionoffreeorcheapcoalbytheprojectdirectlycontributestothecumulativehealthburdenfromindoorexposuretocoalsmoke.WerecommendthattheFinalEISincorporatetheseverelycompromisedexistingpublichealthenvironmentintoitscumulativehealthimpactsassessmentandincludecommitmentstomitigationfortheproject’scontributiontotheongoingenvironmentaljusticeandcumulativehealthimpacts.PleaseseetheenclosedDetailedCommentsforourrecommendationsregardingmitigation.EPAappreciatestheopportunitytoreviewthisDEISandlooksforwardtocontinuedcoordinationwithOSM,BIA,andtheothercooperatingagenciesduringtheNEPAprocess.WhentheFinalEISisreleasedforpublicreview,pleasesendonecopytotheaddressabove(mailcode:CED-2).Ifyouhaveanyquestions,pleasecontactmeat(415)972-3521,orcontactKarenVitulario,theleadreviewerforthisproject,at415-947-4178orvitulano.karen@epa.gov.Sinceely,KathleenMartynGoforth,ManagerEnvironmentalReviewSectionEnclosure:SummaryofEPARatingDefinitionsEPA’sDetailedComments2

### 3

cc: Ben Shelly, President, Navajo Nation Stephen B. Etsitty, EPA Director, Navajo Nation Herman Honanie, Chairman, Hopi Tribe Gayl Honanie, Environmental Director, Hopi Tribe

## S U MM ARY O F E P A RA T I N G D E F I N I T I O N S

T h i s r a ti n g s y s t e m w a s d e v e l op e d a s a m ea n s t o s u mm a r i z e E P A ' s l e v e l o f c on ce r n w it h a p r opo s e d ac ti on.
T h e r a ti n g s a r e a c o m

b i n a ti on o f a l ph a b e ti ca l ca t e g o r i e s f o r e v a l u a ti on o f t h e e n v i r on m e n t a l i m p ac t s o f t h e

p r opo s a l a nd nu m e r i ca l ca t e g o r i e s f o r e v a l u a ti on o f t h e a d e qu ac y o f t h e E I S

.



### E NV I R O N M E N T A L I M P AC T O F T H E AC T I O N

" L O " ( L a c k o f O b j ec ti o n s )

T h e E P A r e v i e w h a s no t i d e n ti f i e d a n y po t e n ti a l e n v i r on m e n t a l i m p ac t s r e qu i r i n g s ub s t a n ti v e c h a n g e s t o t h e

p r opo s a l

. T h e r e v i e w m a y h a v e d i s c l o s e d oppo r t un iti e s f o r a pp li ca ti on o f m iti g a ti on m ea s u r e s t h a t c ou l d b e

acc o m p li s h e d w it h no m o r e t h a n m i no r c h a n g e s t o t h e p r opo s a l

.

" EC " ( E n v i r o n m e n t a l C o n ce r n s )

T h e E P A r e v i e w h a s i d e n ti f i e d e n v i r on m e n t a l i m

p ac t s t h a t s hou l d b e a v o i d e d i n o r d e r t o f u ll y p r o t ec t t h e

e n v i r on m e n t

. C o rr ec ti v e m ea s u r e s m a y r e q u i r e c h a n g e s t o t h e p r e f e rr e d a lt e r n a ti v e o r a pp li ca ti on o f

m iti g a ti on m ea s u r e s t h a t ca n r e du ce t h e e n v i r on m e n t a l i m p ac t

. E P A w ou l d li k e t o w o r k w it h t h e l ea d a g e n c y

t o r e du ce t h e s e i m

p ac t s

.

"

E O " ( E n v i r o n m e n t a l O b j ec ti o n s )

T h e E P A r e v i e w h a s i d e n ti f i e d s i g n i f i ca n t e n v i r on m e n t a l i m

p ac t s t h a t m

u s t b e a v o i d e d i n o r d e r t o p r o v i d e

a d e qu a t e p r o t ec ti on f

o r t h e e n v i r on m e n t

. C o rr ec ti v e m ea s u r e s m a y r e qu i r e s ub s t a n ti a l c h a n g e s t o t h e

p r e f e rr e d a lt e r n a ti v e o r c on s i d e r a ti on o f s o m e o t h e r p r o j ec t a lt e r n a ti v e ( i n c l ud i n g t h e no ac ti on a lt e r n a ti v e

o r a n e w a lt e r n a ti v e )

. E P A i n t e nd s t o w o r k w it h t h e l ea d a g e n c y t o r e du ce t h e s e i m p ac t s

.

" E U " ( E n v i r o n m e n t a ll y U n s a ti s f a c t o r y )

T h e E P A r e v i e w h a s i d e n ti f i e d a d v e r s e e n v i r on m e n t a l i m p ac t s t h a t a r e o f s u ff

i c i e n t m a g n it ud e t h a t t h e y a r e

un s a ti s f ac t o r y fr o m t h e s t a ndpo i n t o f pub li c h ea lt h o r w e l f a r e o r e n v i r on m e n t a l qu a lit y

. E P A i n t e nd s t o w o r k

w it h t h e l ea d a g e n c y t o r e du ce t h e s e i m p ac t s

. I f t h e po t e n ti a ll y un s a ti s f ac t o r y i m p ac t s a r e no t c o rr ec t e d a t

t h e f i n a l E I S s t a g e
, t h i s p r opo s a l w ill b e r ec o mm e nd e d f o r r e f e rr a l t o t h e C E Q

.



### AD E Q UACY O F T H E I M P AC T S T A TE M E N T

C a t e go r y 1 " ( A d e q u a t e )

E P A b e li e v e s t h e d r a f

t E I S a d e qu a t e l y s e t s f

o r t h t h e e n v i r on m e n t a l i m p ac t ( s ) o f t h e p r e f

e rr e d a lt e r n a ti v e a nd

t ho s e o f t h e a lt e r n a ti v e s r ea s on a b l y a v a il a b l e t o t h e p r o j ec t o r ac ti on. N o f

u r t h e r a n a l y s i s o r d a t a c o ll ec ti on i s

n ece ss a r y , bu t t h e r e v i e w e r m a y s u gg e s t t h e a dd iti on o f c l a r i f y i n g l a n g u a g e o r i n f

o r m a ti on.

" C a t e go r y 2 " ( I n s u ff i c i e n t I n f o r m a ti o n )

T h e d r a f t E I S do e s no t c on t a i n s u ff i c i e n t i n f o r m a ti on f

o r E P A t o f

u ll y a ss e ss e n v i r on m e n t a l i m p ac t s t h a t s hou l d

b e a v o i d e d i n o r d e r t o f

u ll y p r o t ec t t h e e n v i r on m e n t

, o r t h e E P A r e v i e w e r h a s i d e n ti f i e d n e w r ea s on a b l y

a v a il a b l e a lt e r n a ti v e s t h a t a r e w it h i n t h e s p ec t r u m o f a lt e r n a ti v e s a n a l y s e d i n t h e d r a f t E I S

, w h i c h c ou l d r e du ce

t h e e n v i r on m e n t a l i m

p ac t s o f t h e ac ti on. T h e i d e n ti f i e d a dd iti on a l i n f

o r m a ti on, d a t a
, a n a l y s e s , o r d i s c u ss i on

s hou l d b e i n c l ud e d i n t h e f i n a l E I S

.

" C

a t e go r y 3 " ( I n ad e q u a t e )

E P A do e s no t b e li e v e t h a t t h e d r a f t E I S a d e qu a t e l y a ss e ss e s po t e n ti a ll y s i g n i f i ca n t e n v i r on m e n t a l i m

p ac t s o f t h e

ac ti on, o r t h e E P A r e v i e w e r h a s i d e n ti f i e d n e w
, r ea s on a b l y a v a il a b l e a lt e r n a ti v e s t h a t a r e ou t s i d e o f t h e s p ec t r u m

o f a lt e r n a ti v e s a n a l y s e d i n t h e d r a f t E I S

, w h i c h s hou l d b e a n a l y s e d i n o r d e r t o r e du ce t h e po t e n ti a ll y s i g n i f i ca n t

e n v i r on m e n t a l i m

p ac t s

. E P A b e li e v e s t h a t t h e i d e n ti f i e d a dd iti on a l i n f

o r m a ti on, d a t a
, a n a l y s e s
, o r d i s c u ss i on s

a r e o f s u c h a m a g n it ud e t h a t t h e y s hou l d h a v e f u ll pub li c r e v i e w a t a d r a f t s t a g e

. E P A do e s no t b e li e v e t h a t t h e d r a f t E I S i s a d e qu a t e f

o r t h e pu r po s e s o f t h e N E P A a nd / o r S ec ti on 309 r e v i e w
, a nd t hu s s hou l d b e f o r m a l l y

r e v i s e d a nd m a d e a v a il a b l e f o r pub li c c o mm e n t i n a s upp l e m e n t a l o r r e v i s e d d r a f t E I S

. O n t h e b a s i s o f t h e

po t e n ti a l s i g n i f

i ca n t i m p ac t s i n v o l v e d, t h i s p r opo s a l c ou l d b e a ca nd i d a t e f o r r e f e rr a l t o t h e C E Q

.

* F r o m E P A M a nu a l 1640

, “ P o li c y a n d P r o ce d u r e s f o r t h e R e v i e w o f F e d e r a l A c ti o n s I m p ac ti ng t h e E nv i r o n m e n t

. ”

### 1

EPA DETAILED COMMENTS ON THE FOUR CORNERS POWER PLANT AND NAVAJO MINE ENERGY PROJECT
DRAFT ENVIRONMENTAL IMPACT STATEMENT, NAVAJO NATION, NEW MEXI CO, JUNE 26 , 2014



### C oal C ombustion R esidue (CCR) Management and Contamination

CCR management at the Four Corners Power Plant EPA expects to finalize the CCR rule by the end of 2014

, which will determine whether CCR is managed as hazardous waste under Subtitle C of the Resource Conservation and Recovery Act (RCRA)

, as solid waste under Subtitle D of RCRA , or in some other manner . The DEIS indicates that CCR at the

F our C orners P ower P lant will be managed in accordance with this final EPA determination, and notes
that

, if EPA regulates CCR through Subtitle D, the authority to implement the regulations would be at the state level, which would not apply on tribal lands (p. 4.15

- 5). OSM proposes mitigation to address

this regulatory gap, and we agree this is necessary. However, the DEIS identifies the mitigation measures as voluntary recommendations to Arizona Public Service

, while also p ortraying them a s if they were legal requirement s

. For example, on page 4.15

- 27

, the DEIS states that both new and exis ting disposal units would be subject to groundwater monitoring requirements and

, if certain hazardous constituents are detected at a level exceeding groundwater protection standards, the FCPP would have 90 days to assess corrective measures and select a re medy that would protect human health and the environment. It is not clear what groundwater protection standards are being referenced. The DEIS notes that the Navajo Nation does not have groundwater quality standards (p. 4.15

- 18). Additionally

, the speci fic timeline and reference to corrective measures imply a rigorous enforcement program. The

h azardous and solid w aste m itigation m easures on p ages 4.15

- 31 through 4.15

- 32 reference a “permit program” and “inspection requirements” and specify operating, design, groundwater monitoring, corrective action, and closure and post

- closure requirements

, but these “requirements” are simply recommendations to APS ( “OSMRE recommends APS implement the measures below”

– p. 4.15

- 31).

Recommendations: T he hazardous and solid waste mitigation measures presented on pages 4.15

- 31 through 4.15

- 32 should be enforceable conditions of the project since it is a possibility that coal ash could be regulated under Subtitle D and the standards would not have an enf orcement agency on tribal lands. We strongly agree with the need for the identified operating, design, groundwater monitoring, corrective action, and closure and post

- closure requirements

. Office of Surface Mining, Reclamation and Enforcement does not ha ve a federal action at the FCPP

, but

the BIA is a cooperating agency and is using this EIS to inform its decision on the FCPP lease

renewal. T he hazardous and solid waste mitigation measures should be conditions of BIA’s lease approval and enforceable thr ough BIA’s lease conditions and its NEPA Record of

Decision. We recommend that they be identified as such in the Final EIS.

C ontamination from past CCR mine disposal Contamination from coal combustion residue (CCR) placed at the Navajo Mine has leached, and will continue to leach, directly into groundwater of the Fruitland Formation coal seams and the P ictured

C liffs S andstone Formation. The DEIS acknowledges “ high levels of chemical constituents of concern exist within the wells in the historic mining area ” (p. 4.5

- 44). The DEIS concludes

, however

, that “ Thus far, negligible impacts have resulted from the CCR placement. It is also unlikely that any significant future effects will ensue from the CCR placement at the Navajo Mine because of the very slow

g roundwater movement and the likely attenuation of contaminants of concern as they migrate through the subsurface ” and that “ Therefore, past CCR placement at the Navajo Mine is determined to have no impact in the short

- or long

- term ” (p. 4.5

- 1 4). Elsewhere it states that the potential impacts to current and future water uses from CCR placement at the Navajo Mine are minor (p. 4.5

- 44), despite the identified major impacts for pH, b oron, s elenium, f luoride and s ulfate (p. 4.5

- 44) , with concentrations of

### 2

b oron
, f luoride, s ulfate, and t otal d issolved s olids ( TDS ) exceeding the criteria for livestock watering , a designated post reclamation land use

.

These conclusions, especially that of “no impact”

, do not appear to be supported. The modeling assumption that contaminants would be attenuated as they migrate through the subsurface has not been

confirmed 1



### . Additionally, t he assumption that pollutants would be diluted by the larger San Juan River groundwater flow, even if they are not attenuated during transport to the Fruitland Formation, is brought into question since the transport modeling and sampling that occurred seems to have not fully recognized the possibility of a significant vertical (fracture) flow in the Fruitland Formatio n . T he DEIS indicates that the general flow direction of groundwater in the Fruitland Formation is downward through the interbedded shale and coal units to the lower strata of the Fruitland Formation, with marginal upward

movement from the P ictured Cliffs S andstone into the Fruitland Formation (p. 4.5

- 13). One can infer from the vertical flow directions that fracture flow might play a prominent role in the movement of bedrock groundwater in the FCPP area 2 

### . This parameter was not considered in the groundwa ter modeling of the FCPP area. If vertical (and lateral) fracture flow is substantial, the assumed attenuation would not occur because fracture flow results in a much smaller residence time of groundwater in the bedrock formations and a limited opportunit y for the contaminants to be adsorbed by bedrock clay. This

would lead to a potentially larger groundwater impact downgradient of CCR placement than is predicted

in the DEIS

.

The DEIS is not clear whether any ongoing groundwater or surface water monitoring w ould occur as a condition of this project. The DEIS seems to indicate that only groundwater and surface water monitoring that are part of the new SMCRA permit groundwater monitoring plan (originally from BHP Navajo Coal Company

, but which the Navajo Transitional Energy Company will implement) would occur, which relate s to the new mine areas and the Pinabete and Cottonwood arroyos . It does not specify any monitoring of the historic contamination areas nor confirm that contaminated groundwater i s not reaching the San Juan or Chaco R iver surface water or alluvia

.

Recommendation: The FEIS should include additional information to support its groundwater and surface water impact assessment conclusions. We recommend that monitoring of groundwater q uality at Areas I and II of the Navajo Mine and the San Juan River alluvium occur to confirm the model predictions that constituents of concern would be attenuated as

1 The DEIS references the “Cumulative Hydrologic Impact Assessment of the BHP Billiton Navajo Coal Company, N avajo Mine” for this assumption

, but this assessment is not summarized nor appended to the DEIS.

2 Wilson, T.H. et al., (2012): “Fracture and 3D seismic interpretations of the Fruitland Formation and cover strata: Implications for CO 2 retention and tracer movement, San Juan Basin Pilot test”. International Journal of Coal Geology

, Volume 99 , 1 September 2012, Pages 35

– 53. http://www.sciencedirect.com/sc ience/article/pii/S0166516212000432

McCord, J. et al., (1992) “Heat

- flow data suggest large ground

- water fluxes through Fruitland coals of the northern San Juan basin, Colorado

- New Mexico”, International Journal of Coal Geology , v. 20 no. 5, 1992, p. 419

- 4 22. http://dx.doi.org/10.1016/j.coal.2012.02.007

Haerer and McPherson (2008) “Evaluating the impacts and capabilities of long term subsurface storage in the context of carbon sequestration in the San Juan basin, NM and CO”. Energy Procedia

, Volume 1, Issue 1 , February 2009, Pages 2991

– 2998. Proceedings of the 9th International Conference on Greenhouse Gas Control Technologies (GHGT

- 9), 16

– 20 November 2008, Washington DC, USA. http://www.sciencedirect.com/science/article/pii/S187661020900719X

### 3

groundwater travels towards the San Juan River and the Chaco River. Because the groundwa ter
of the Fruitland and P ictured C liffs S andstone formations that enter into the alluvium also discharges into the San Juan River in the area of the Navajo Mine, monitoring of the San Juan River surface water quality upstream, along the mine reach, and do wnstream should occur if the groundwater monitoring results identify elevated levels of pollutants in the San Juan River

alluvium that exceed Navajo Nation Water Quality Standards

.

In addition, the baseline groundwater quality should be clarified. The DEIS summarizes baseline results for Cottonwood, Pinabete, and No Name Arroyo alluvial wells in Table 4.5

- 5 ; however the presentation of this information is not useful. EPA previously commented that this summary does not allow an assessment of ground wate r impacts by source

, and we recommended including some mon itoring results by well in the D EIS. In addition, t he identification/location of

these baseline wells is of importance in order to confirm they do

, indeed

, represent baseline

conditions and do not include contamination that is related to past CCR disposal . This

information should be included in the FEIS

.

Monitoring for CCR contamination from Four Corners Power Plant

The DEIS reports two areas of groundwater seepage at the existing Dry Fly Ash Disposal Areas (DFADAs) k nown as the “north seep” and “ south seepage area”

, which have contaminated groundwater (p. 4.5

- 57)

. According to the DEIS, APS has installed extraction wells and constructed the north intercept trench to collect seepag e and prevent contamination of the Chaco River , and is currently constructing a south i ntercept trench to remediate groundwater to protect the river. The DEIS does not

i ndicate how the groundwater is being remediated. With this action and the monitoring of the existing trenches, the DEIS concludes that continued operation and expansion of the DFADAs would have less potential to contaminate local groundwater and water quality in Chaco Wash (p. 4.5

- 57)

.

We believe that such actions to capture and treat contaminated groundwater are necessary to ensure that the continued operation and expansion of the DFADAs does not contribute significantly to the existing pollutant load in the Chaco River. The operation of the intercept trenches, as well as the monitori ng of groundwater in existing and

, possibly

, new monitoring wells, is critical to ensuring that any pollutant sources present in ground water that re

- surfaces via seeps can be traced so that appropriate corrective

actions can be undertaken.

Recommendati on: We recommend that any FCPP lease renewal by the BIA include conditions requiring the continued monitoring and remediation of groundwater at the DFADAs. We also recommend that the FEIS identify the method of groundwater remediation that is occurring o r will occur.

Dam Safety We appreciate the information in the DEIS that states that all recommendations from the 2009 Coal Ash Impoundment

– Site Specific Assessment Report for the FCPP were completed in 2009 (p. 4.14

- 4). On p. 4.15

- 22 , however, the DEIS states that APS indicated that the suggested items would be addressed and completed prior to the end of 2009. The DEIS specifically identifies some of the recommendations

, but does not indicate whether the following are occurring: (From section 12.4 of the recommendations):

 Continue monitoring seepage at the downstream toe of the south embankment (Pond #4 toe) for any changes in seepage quantity and flow rate or evidence that the flow is carrying soil/ash particles from the embankment.

### 4

 Expand pr ogram to include additional monitoring of potential seepage under the dam at the northwest corner of the LAI, where the LAI embankment was not tied

- in to the underlying

Pond 3

- 4 embankment to provide continuity of seepage control, and where a potential see page pathway exists if the HDPE lining fails. Install additional piezometers to address this potential seepage pathway and expand documentation in APS dam safety inspections to note any evidence of seepage near the downstream toe of the dam in this area.

 Repair or replace the two settlement plates that do not appear to be providing useful information and that may have been damaged during construction or maintenance activities.

Recommendation: For clarity in the FEIS, indicate whether the above recommend ed actions and monitoring from the 2009 Coal Ash Impoundment

– Site Specific Assessment Report for the FCPP

are occurring. If the requested monitoring has occurred, include results of seepage monitoring

efforts

.

Dust Control from CCR Management The DEIS provides information regarding the FCPP Dust Control Plan. The DEIS states that, “During placement of CCR, compaction control, added moisture, and slope control are used, as well as dust suppressant and periodic fabric covering of slopes” . The DEIS states that DFADA 1 and 2 will continue to be used until they reach capacity in 2016. DFADA 1 is tallest on the west berm, approximately 110 feet above natural grade (p. 4.15

- 12). The DEIS also states that APS would

construct five additional DFADAs to accommodate future disposal of all fly ash, bottom ash, and flue gas desulfurization waste generated through the duration of the lease term. Each site is anticipated to be approximately 60 acres and approximately 120 feet high (p. xiii and p. 3

- 15). On page 4.15

- 27, the DEIS states that the new DFADA’s would be approximately 80 feet high, so it is not clear which height represents the height above natural grade.

If the height of the DFADAs will be 120 feet above natural grade, t o th e extent there is any settlement in

the down

- wind directions, fugitive dust control on such a high active face would be difficult to maintain

. EPA has received complaints from nearby residents regarding fugitive dust, therefore renewed efforts at

dust con trol

, and monitoring of dust control effectiveness

, is essential.

Recommendation: Clarify in the FEIS whether the height of the DFADAs will be 80 feet or 120 feet above natural grade. For either heig ht, we recommend that the DFADA s be continu ously

spra yed with water to ensure dust is controlled. Slope control and the other dust control measures in the Dust Control Plan should be monitored regularly to ensure they are effective. When wind speeds are elevated, more frequent dust control should be implem ented.

We recommend that a dust complaint procedure and hotline be developed to allow local residents

to report ineffective dust control conditions . APS should conduct outreach to the local population , in Navajo as well as English, to ensure awareness of this complaint procedure.

Cumulative Health Impacts The EIS should acknowledge the cumulative health impacts that the residents in the vicinity of the project experience. The DEIS largely relies on the air quality analysis conclu sions for its public health impact assessment. The DEIS s tate s that the combined impacts to air quality from the Navajo Mine and

the Four Corners Power Plant (FCPP) are minor (p. 4.1

- 85) because modeled criteria pollutant emissions

meet the National Ambie nt Air Quality Standards (NAAQS). EPA sets the NAAQS at a level requisite to protect public health with an adequate margin of safety, taking into consideration effects on

### 5

susceptible populations

, based on the scientific literature ; h owever, as we previous ly commented, E PA’s

Particulate Matter a nd Ozone Integrated Science Assessments (U.S. EPA, 2009 and U.S. EPA, 2013) determined that there is no evidence of a population

- level threshold in PM

- and ozone

- related health

effects in t he epidemiological literatu re . This means that there is not a level below which is there is no impact. Instead, h ealth impacts that occur below the standards are assumed to be more uncertain than those occurring above the standards

.

The DEIS acknowledges that the cumulative pub lic health effects depend on the respiratory health status of residents in the area (p. 4.18

- 54)

, yet it does not appear that respiratory health was considered in the

conclusions that project impacts to public health from the FCPP are negligible for criteria pollutants (p.

xli , p. 4.17

- 22 ) and minor for hazardous air pollutants (p. p. 4.17

- 24)

, and that cumulative impacts to public health from both the FCPP and the Mine are minor (p. 4.18

- 54)

. The DEIS does disclose San Juan County’s most recent Community Health Profile , which found that San Juan County has a higher

incidence of chronic lo wer respiratory disease

, comprised of chronic bronchitis, asthma, and emphysema

, compared to New Mexico or the rest of the United States. It also cites a study by the New Mexico Department of Health that found that San Juan County residents are 34 percent more likely to

have asthma

- related medical visits after 20 parts per billion increases in local ozone levels ( p. 4.17

- 4). A study by Bu n nell , et al, also cite d in the DEIS, documents disproportionately high rates of respiratory

disease in the Indian Health Service’s Shiprock Service area (p. 4.11

- 14)

. None of this information

appear s to have been factor ed in to the DEIS ’ conclusions regarding cumulative public health impacts

.

The DEIS also discusses the unique situation of in

- home coal burning from coal provided free of charge

to Navajos who reside within a certain radius of the mine , which was part of the original mining lease

agreement

. The DEIS states that

, f rom October through March, coal for personal use by project employees and local Chapter residents is placed in the Community Coal Stockpile, located adjacent to

the Nava jo Mine Area III office (p. 2

- 12 ). Because many Navajo are able to obtain cheap or free coal, and they do not have access , or affordable access, to electricity

– an existing environmental justice vulnerability

- - many use coal to heat their homes. It is not unusual for the coal to be burned in stoves that were not designed to burn c oal, nor is it unusual that the stoves are poorly maintained or improperly

vented. The Bunnell study revealed that air quality from coal c ombustion inside dwellings used for cooking and heating had an average 24

- h ou r wintertime PM 2.5 

### level exceed ing EPA’s ambient air

standard for PM 2.5 

### (note that EPA does not regulate indoor air pollution levels). This cumulative impact, which directly relates to the mine operation s for which this EIS is being prepared , should be considered in the cumulative public health impact conclusions

, as well as referenced in the environmental justice impact conclusions

.

Recommendation: We recommend that the cumulative public health impact assessment

conclusions factor in the respiratory health status of residents in the area, as the DEIS states should occur on page 4.18

- 54. The FEIS should document how the lack of access to electric power and the provision of free or low

- cost coal by the project have contributed to indoor air quality cumulative impacts

, as well as outdoor air pollution during stagnant winter weather

conditions

. Because the DEIS does not define what would constitute a moderate or major impact to cumulative public health and does not define a level of significance, we recommend identifying mitigation measures fo r this impact

, since the existing public health environment is severely compromised (h ealth outcomes for Navajo are worse than for the general population in San Juan County ; l ife expectancy is lower, mortality rates far exceed the national rates ; i nvestmen t in healthcare services on Navajo land is about half of that for the general population ; and h ealthcare disparities between Navajo and the general population are pronounced due to lack

### 6

of access and funding

- p. 4.10

- 15). The DEIS notes that the results from th e Bunnell study suggest that the added risk f r o m in

- home coal burning could be reduced by making relatively simple and inexpensive changes to methods of home heating (p. 4.17

- 4). Such changes should be further discussed and identified as possible m itigation for this cumulative public health and environmental justice impact.

EPA previously recommended mitigation for cumulative impacts from in

- home coal combustion supplied by the continued operation of the mine. At a minimum, the following potential

m itigation measures should be identified and considered : funding for replacement of old stoves with more efficient stoves appropriate for the fuel types being used; funding for replacement of old coal and wood stoves with propane gas heaters; ass istance to the affected community for residential solar, wind or other electrical generation projects ; assistance to Navajo Tribal Utility Authority for local electricity connections and subsidies to any affected residents ; and education

on how to properly operate, vent, and maintain existing stoves, perhaps locating this information in Navajo at the Community Coal Stockpile or producing an instructional video to play in Indian Health Service clinic waiting rooms

. Selection of any of the above measures sho uld be done in

consultation with the affected residents.

Excluding Fugitive Dust from the Human Health Risk Assessment (HHRA) EPA previously commented that fugitive dust should have been included in the Human Health Risk

Assessment and that unce rtainty regarding the assumption of equal toxicity of PM species does not warrant the exclusion of fugitive dust from the impacts analysis (on the basis of having a lower proportion of metals and other toxic substances). OSM has chosen , instead, to includ e a discussion of potential impacts from PM 2.5 

### , including baseline and projected future emissions.

Recommendation: We recommend that the F EIS clearly state that fugitive dust was not included

in the HHRA.

Potential for Mine Methane Capture The DEIS quantifies the fugitive methane emissions that would be liberated from coal seams during mining (p. 4.2

- 22). Methane has a global warming potential more than 20 times higher than CO 2 

### for a

100

- year period 3



### . Methane can be captured at surface mines through pre

- mine dr ainage , either from the surface or through horizontal boreholes. EPA is aware that t here are surface mines in operation in the

Powder River B asin in Wyoming and elsewhere around the world that are recovering methane through

pre

- mi ne drainage and

, thus

, mitigating the impact from this powerful greenhouse gas

. Also note that

surface mine methane capture is now eligible for carbon credits

- a market tracking system that supports the implementation of California’s Cap

- and

- Trade Progra m

- for greenhouse gas emission r eductions associated with the capture and destruction of methane in the U.S. that would otherwise be vented into the atmosphere as a result of mining operations at active underground and surface coal mines. See: http://www.arb.ca.gov/newsrel/newsrelease.php?id=602

. In addition, the DEIS states that BIA is currently evaluating , under NEPA, Western Oil & Gas’s proposal to develop 600 natural gas wells in the Burnham, Upper Fruitland, and Nenahnezad/San Juan Chapters, which would involve the installation of new pipeline (p. 4.18

- 13).

3 http://www.epa.gov/climatechange/ghgemissions/gases .html

### 7

Recommendation: We recommend that the FEIS discuss the feasibility of capturing methane from Navajo Mine. Include the economic benefits that could occur from selling the carbon

credits in California’s Cap

- and

- Trade Program 

### , as well as the possible interconnection or use of natural gas infrastructure nearby from Western Oil & Gas’s proposed natural gas wells

.

Additional information regarding methane recovery at surface mines is available in the following

EPA documents:

 

### “Case Study

– Methane Recovery at Surface Mines”

- http://epa.gov/coalbed/docs/CMOP

- Methane

- Recovery

- Surface

- Mines

- March

- 2014.pdf

 “US Surface Coal Mine Methane Recovery Opportunities”

- http://epa.gov/coalbed/docs/cmm_recove ry_opps_surface.pdf

Petroleum Contamination

The DEIS states that “ Secondary containment is not provided for mobile refueling vehicles in areas where NTEC staff are present, and the maximum amount of time before a discharge would be detected is

less than 24 hours ” (p. 4.15

- 6). It is unclear why it could take hours before a discharge from mobile refueling is detected. The DEIS states that the bioremediation of petroleum

- contaminated soils takes place on

- site (p. 4.15

- 6). The source of this contaminated s oil is not identified.

Recommendation: The FEIS should identify the source of the petroleum

- contaminated soils and indicate whether they are originating from mobile refueling operations. We recommend that the applicant review and , as needed, update its Spill Prevention, Control, and Countermeasure (SPCC) Plan to i dentify applicable general containment or drainage control measures

, as required by 40 CFR 112.7(c) for mobile refuelers and mobile refueling

, to ensure that releases

associated with these o perations are detected as soon as possible. For the continued operation of the FCPP and Navajo Mine, we recommend that additional measures be explored to prevent and

contain releases when mobile refuelers may be unattended and during mobile refueling

oper ations.

Additional comments

 Table 4.1

- 28 on p. 4.1

- 67 is confusing. The second column is labeled “Estimated Post

- 2014
Baseline Emissions”

, but it is not clear what is meant by post

- 2014 emissions. The text says that

the reductions in the third column represent the reductions from ful ly implementing BART , but

our estimate for mercury reductions under BART implementation is 61%, not the 81% listed. It is possible that the table is intended to represent the additional reductions in mercury that could

oc cur from implementation of the mercury and air toxics standards ( MATS )

. If so, this should

be clarified in the FEIS and a definition of “Post

- 2014 Baseline Emissions” should be provided.

 In Table 4.5

- 6 on page 4.5

- 20, the result for mercury is listed as >0.001

. Should this have been

< 0.001 ?

 In the Hazardous and Solid Waste chapter, the PDEIS states that “specific study of the disposal of CCR in Navajo Mine has not identified adverse effects” (p. 4.15

- 5). This does not appear to be supported

, given the contamination identified in the Water Resources chapter. Groundwater

contamination is an adverse effect

.