United States Environmental Protection Agency, Region 9

NHPA Project Description Summary

McElmo Creek Unit Oil Production Facility, PSD Permit No. NU 05-01

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National Historic Preservation Act Section 106 Consultation

Project Description Summary

McElmo Creek Unit Oil Production Facility

Proposed Amended Clean Air Act Prevention of Significant Deterioration Permit 

PSD Permit No. NU 05-01

September 30, 2015

INTRODUCTION

The United States Environmental Protection Agency, Region 9 (EPA) is acting on an application 

for an amendment to a Clean Air Act Prevention of Significant Deterioration (PSD) air quality 

permit, in accordance with the Clean Air Act and the PSD air quality regulations (40 CFR 

52.21), for the gas flare (called the “Main Flare”) at the McElmo Creek Unit Oil Production 

Facility (MCU Facility or Facility), an existing oil and gas production operation. Pursuant to 

Section 106 of the National Historic Preservation Act (NHPA), 54 U.S.C. §100101 et seq., and 

its implementing regulations at 36 CFR Part 800, prior to issuing the permit amendment, EPA is 

required to take into account the effects of its undertaking (e.g. issuance of a permit amendment)

on historic properties listed in or eligible for inclusion in the National Register of Historic Places. 

Consultation with the State Historic Preservation Officer and/or the Tribal Historic Preservation 

Officer is required for all undertakings that have the potential to affect historic properties. 

Section 106 consultations assess whether historic properties exist within an undertaking’s area of 

potential effects (APE) and, if so, whether the undertaking will adversely affect such properties. 

The term “historic properties” means prehistoric or historic districts, sites, buildings, structures, 

or objects included in, or eligible for inclusion in, the National Register of Historic Places 

maintained by the Department of the Interior. The EPA is the lead federal agency for this 

undertaking. As such, EPA must meet its NHPA Section 106 obligations for this project prior to 

issuing a final permit decision.

DESCRIPTION OF THE UNDERTAKING

EPA’s undertaking, as defined in 36 CFR 800.16(y) and which triggers the application of the 

NHPA, is the issuance of an amended PSD air quality permit (PSD Permit) for the Main Flare at 

the MCU Facility. While the Facility is an existing oil and gas production operation located on 

the McElmo Creek Unit oilfield in San Juan County, Utah, EPA’s action is focuses on the 

existing Main Flare, which is used to control pollution from the operation of the MCU Facility. 
NHPA Cultural Resources Summary

McElmo Creek Unit Oil Production Facility, PSD Permit No. NU 05-01

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The MCU Facility is located in Section 31, Township 40 South, Range 25 East within the Four 

Corners area on the Navajo Nation Reservation near the city of Aneth, San Juan County, Utah.

(See Figure 1.) The MCU Facility is also located on the McElmo Creek Unit oilfield, which is 

one of four oilfield units in the greater Aneth oilfield on the Navajo Nation Reservation in 

southeastern Utah. (See Figure 2.)

Figure 1: Location of McElmo Creek Unit Oil Production Facility

The MCU Facility started operation in the 1950s and was owned by Superior Oil at the time. 

Mobil Exploration and Producing U.S. Inc. (Mobil) purchased the Facility in 1984. Resolute 

Natural Resources Company (Resolute), in partnership with Navajo Nation Oil and Gas 

Company, acquired Mobil’s ownership interest in April 2006 and assumed operation of the 

Facility on June 1, 2006. 

The field operations located on the McElmo Creek Unit oilfield consist of approximately 90 

producing wells where petroleum crude oil is recovered from producing strata, brought to the 
NHPA Cultural Resources Summary

McElmo Creek Unit Oil Production Facility, PSD Permit No. NU 05-01

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surface to be stored at either a satellite or a tank battery. There are eleven satellites that function 

as testing facilities for producing wells and four tank batteries. The gas compression plant is 

used to support tertiary recovery of crude oil in the McElmo Creek Unit oilfield, and includes the 

Main Flare. 

EPA’s PSD Permit action is to incorporate pollution limits, terms, and conditions of a federal 

Consent Decree (United States v. Mobil Exploration and Producing U.S. Inc., Case No. 2:05-

CV-319, filed June 8, 2005) for the Main Flare at the MCU Facility’s gas compression plant. 

These pollution limits, terms, and conditions include Best Available Control Technology 

(BACT) emission limitations for nitrogen oxides, carbon monoxide, sulfur dioxide, and volatile 

organic compounds for the Main Flare.

Figure 2: Oil field Units in the Aneth Oil Field

(Source: Resolute Natural Resources Company)
NHPA Cultural Resources Summary

McElmo Creek Unit Oil Production Facility, PSD Permit No. NU 05-01

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Additionally, EPA is amending the permit to remove certain equipment, and the applicable 

permit requirements that apply because this equipment has been shut down and removed from 

the site. Other than the potential replacement of an existing fan to provide better pollution control 

at the Main Flare, EPA’s amendments to the PSD permit do not authorize any new construction 

or modification of existing equipment at the MCU Facility.

On October 15, 2014, EPA issued the amended PSD Permit for public comment. A final permit 

decision will be issued following completion of the Agency’s NHPA Section 106 consultation

process.

AREA OF POTENTIAL EFFECTS

Since the EPA’s permit action does not authorize any new construction or modification of 

existing equipment at the MCU Facility, other than potential replacement of an existing fan at the 

Main Flare, this action is not expected to result in any new ground disturbance or change in 

operations at the MCU Facility. As such, in consultation with the Navajo Nation Historic 

Preservation Department (NNHPD), the APE for this project consists of an area within a 2 km 

(1.2 miles) radius around the Main Flare as shown in Figure 3. 

Figure 3: Map of 2 km Area of Potential Effects for MCU Facility

HISTORIC PROPERTIES & CULTURAL RESOURCES WITHIN THE AREA OF POTENTIAL EFFECTS

Resolute Natural Resources, LLC, contracted with Dinétahdóó Cultural Resources Management 

(DCRM) to identify historic properties, as defined by the NHPA and its implementing 

regulations, within the APE of 2 km of the Main Flare. DCRM’s assessment of historic 
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McElmo Creek Unit Oil Production Facility, PSD Permit No. NU 05-01

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properties, dated September 2, 2015 (DCRM Report), is provided as an attachment to this 

Cultural Resources Report document. 

Prior to conducting the fieldwork, DCRM examined records at the NNHPD office in Window 

Rock, Arizona, to determine whether cultural resources inventories had been performed within 

the project area. DCRM identified fifty (50) previously recorded archaeological sites within the 

APE based upon a literature search conducted at the NNHPD records room. These specific sites 

are described in the DCRM Report. None of these sites were determined to be listed in the 

National Register of Historic Places maintained by the Department of the Interior. Under the 

NHPA Section 106 and 36 CFR 60.4, cultural resources may be eligible for nomination to the 

National Register of Historic Places if they are more than 50 years old and “possess integrity of 

location, design, setting, material, workmanship, feeling, and association.” 

Between May 21, 2015 and June 3, 2015, DCRM conducted fieldwork which consisted of 

cultural resource assessments of the historic and in-use properties within the APE. DCRM 

identified and evaluated thirteen (13) historic structures and nine (9) in-use sites. These specific 

historic structures and in-use sites are provided in the DCRM Report. None of these sites were 

determined to be in the National Register of Historic Places maintained by the Department of the 

Interior. 

CONCLUSION

Based on the accompanying information and the opinions already offered by the NNHPD 

regarding this project, EPA has determined that issuance of the amended PSD Permit for the 

Main Flare will have no effect upon historic properties within the APE.