FINAL

Site Inspection Report

High Altitude Aviation Training Site

Gypsum, Colorado

Site Inspection for Perfluorooctanoic Acid (PFOA), Perfluorooctanesulfonic Acid (PFOS), 

Perfluorohexanesulfonic Acid (PFHxS), Perfluorononanoic Acid (PFNA), Hexafluoropropylene 

Oxide Dimer Acid (HFPO-DA), and Perfluorobutanesulfonic Acid (PFBS)

ARNG Installations, Nationwide

August 2023

Prepared for:

Army National Guard Headquarters 

111 S. George Mason Drive 

Arlington, VA 22204

UNCLASSIFIED
This page intentionally left blank
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC i

TABLE OF CONTENTS

Page

LIST OF APPENDICES................................................................................................................iii

LIST OF FIGURES ....................................................................................................................... iv

LIST OF TABLES.......................................................................................................................... v

LIST OF ACRONYMS AND ABBREVIATIONS ...................................................................... vi

EXECUTIVE SUMMARY ...................................................................................................... ES-1

1. INTRODUCTION ............................................................................................... 1-1

1.1 Project Authorization............................................................................... 1-1

1.2 Site Inspection Purpose............................................................................ 1-1

2. FACILITY BACKGROUND.............................................................................. 2-1

2.1 Facility Location And Description........................................................... 2-1

2.2 Facility Environmental Setting ................................................................ 2-1

2.2.1 Geology..................................................................................... 2-2

2.2.2 Hydrogeology ........................................................................... 2-2

2.2.3 Hydrology ................................................................................. 2-4

2.2.4 Climate...................................................................................... 2-4

2.2.5 Current and Future Land Use.................................................... 2-5

2.2.6 Sensitive Habitat and Threatened/Endangered Species............ 2-5

2.3 History of PFAS use ................................................................................ 2-6

3. SUMMARY OF AREAS OF INTEREST........................................................... 3-1

3.1 AOI 1 – Parking Apron/Taxiway............................................................. 3-1

3.2 AOI 2 – HAZMAT Storage Area ............................................................ 3-1

3.3 AOI 3 – Building 1214 ............................................................................ 3-2

3.4 Adjacent Sources ..................................................................................... 3-3

3.4.1 Vail Valley Jet Center............................................................... 3-3

3.4.2 Eagle County Regional Airport ................................................ 3-3

3.4.3 Eagle County Regional Airport Fire Department ..................... 3-4

3.4.4 Gypsum Fire Protection District ............................................... 3-5

3.4.5 Town of Gypsum Wastewater Treatment Plant........................ 3-5

4. PROJECT DATA QUALITY OBJECTIVES ..................................................... 4-1

4.1 Problem Statement................................................................................... 4-1
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC ii

4.2 Information Inputs ................................................................................... 4-1

4.3 Study Boundaries..................................................................................... 4-1

4.4 Analytical Approach ................................................................................ 4-1

4.5 Data Usability Assessment ...................................................................... 4-2

5. SITE INSPECTION ACTIVITIES...................................................................... 5-3

5.1 Pre-Investigation Activities ..................................................................... 5-4

5.1.1 Technical Project Planning ....................................................... 5-4

5.1.2 Utility Clearance ....................................................................... 5-4

5.1.3 Source Water and PFAS Sampling Equipment Acceptability.. 5-5

5.2 Hand Auger Soil Sampling ...................................................................... 5-5

5.3 Soil Borings and Soil Sampling............................................................... 5-5

5.4 Temporary Well Installation and Groundwater Grab Sampling.............. 5-7

5.5 Synoptic Water Level Measurements...................................................... 5-8

5.6 Surveying ................................................................................................. 5-8

5.7 Investigation-Derived Waste ................................................................... 5-8

5.8 Laboratory Analytical Methods............................................................... 5-9

5.9 Deviations from SI UFP-QAPP Addendum ............................................ 5-9

6. SITE INSPECTION RESULTS .......................................................................... 6-1

6.1 Screening Levels...................................................................................... 6-1

6.2 Soil Physicochemical Analyses ............................................................... 6-2

6.3 AOI 1 ....................................................................................................... 6-2

6.3.1 AOI 1 Soil Analytical Results................................................... 6-2

6.3.2 AOI 1 Groundwater Analytical Results.................................... 6-3

6.3.3 Conclusions............................................................................... 6-4

6.4 AOI 2 ....................................................................................................... 6-4

6.4.1 AOI 2 Soil Analytical Results................................................... 6-4

6.4.2 AOI 2 Groundwater Analytical Results.................................... 6-5

6.4.3 Conclusions............................................................................... 6-5

6.5 AOI 3 ....................................................................................................... 6-5

6.5.1 AOI 3 Soil Analytical Results................................................... 6-5

6.5.2 AOI 3 Groundwater Analytical Results.................................... 6-6

6.5.3 Conclusions............................................................................... 6-6

7. EXPOSURE PATHWAYS.................................................................................. 7-1

7.1 Soil Exposure Pathway ............................................................................ 7-2

7.1.1 AOI 1 ....................................................................................... 7-2
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC iii

7.1.2 AOI 2 ....................................................................................... 7-2

7.1.3 AOI 3 ........................................................................................ 7-3

7.2 Groundwater Exposure Pathway.............................................................. 7-3

7.2.1 AOI 1 ........................................................................................ 7-4

7.2.2 AOI 2 ........................................................................................ 7-4

7.2.3 AOI 3 ........................................................................................ 7-4

7.3 Surface Water and Sediment Exposure Pathway..................................... 7-5

7.3.1 AOI 1 ........................................................................................ 7-5

7.3.2 AOI 2 ....................................................................................... 7-5

7.3.1 AOI 3 ........................................................................................ 7-5

8. SUMMARY AND OUTCOME .......................................................................... 8-1

8.1 SI Activities ............................................................................................. 8-1

8.2 Outcome................................................................................................... 8-1

9. REFERENCES .................................................................................................... 9-1

LIST OF APPENDICES

Appendix A. Data Usability Assessment and Validation Reports

Appendix B. Field Documentation

B1. Log of Daily Notice of Field Activities

B2. Sampling Forms 

B3. Survey Data

B4. Field Change Request Form

B5 Investigation-Derived Waste Polygons

Appendix C. Photographic Log

Appendix D. Technical Project Planning Meeting Minutes

Appendix E. Boring Logs and Well Construction Diagrams

Appendix F. Analytical Results

Appendix G. Laboratory Reports
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC iv

LIST OF FIGURES

Figure 2-1 Facility Location

Figure 2-2 Facility Topography

Figure 2-3 Groundwater Features

Figure 2-4 Surface Water Features

Figure 2-5 Groundwater Elevations, July 2022

Figure 3-1 Areas of Interest

Figure 5-1 Site Inspection Sample Locations

Figure 6-1 PFOS Detections in Soil

Figure 6-2 PFOA Detections in Soil

Figure 6-3 PFBS Detections in Soil

Figure 6-4 PFHxS Detections in Soil

Figure 6-5 PFNA Detections in Soil

Figure 6-6 PFOS, PFOA, and PFBS Detections in Groundwater

Figure 6-7 PFHxS and PFNA Detections in Groundwater

Figure 7-1 Conceptual Site Model, AOI 1 

Figure 7-2 Conceptual Site Model, AOI 2

Figure 7-3 Conceptual Site Model, AOI 3
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC v

LIST OF TABLES

ES-1 Screening Levels (Soil and Groundwater)

ES-2 Summary of Site Inspection Findings and Recommendations

5-1 Samples by Medium, High Altitude Aviation Training Site, Gypsum, Colorado,

Site Inspection Report

5-2 Soil Boring Depths and Temporary Well Screen Intervals, High Altitude Aviation 

Training Site, Gypsum, Colorado, Site Inspection Report

5-3 Groundwater Elevation, High Altitude Aviation Training Site, Gypsum, Colorado,

Site Inspection Report

6-1 Screening Levels (Soil and Groundwater)

6-2 PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Surface Soil, Site Inspection 

Report, High Altitude Aviation Training Site

6-3 PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Shallow Subsurface Soil, 

Site Inspection Report, High Altitude Aviation Training Site

6-4 PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Deep Subsurface Soil, Site 

Inspection Report, High Altitude Aviation Training Site

6-5 PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Groundwater, Site Inspection 

Report, High Altitude Aviation Training Site

8-1 Summary of Site Inspection Findings and Recommendations
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC vi

LIST OF ACRONYMS AND ABBREVIATIONS

°C Degrees Celsius

°F Degrees Fahrenheit

% Percent

μg/kg Microgram(s) per kilogram

AECOM AECOM Technical Services, Inc. 

AFFF Aqueous Film Forming Foam

AMEC AMEC Earth and Environmental Inc.

ARFF Aircraft Rescue and Firefighting

AOI Area of Interest

ARNG Army National Guard

ASTM American Society for Testing and Materials

BCC Bird of conservation concern

bgs Below ground surface

CAF Compressed Air Foam

CDPHE Colorado Department of Public Health and Environment

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act

COARNG Colorado Army National Guard 

COC Chain-of-custody

CSM Conceptual site model

DA Department of the Army

DoD Department of Defense

DQI Data quality indicator

DQO Data quality objective

DUA Data Usability Assessment

EA EA Engineering, Science, and Technology, Inc., PBC

EB Equipment Blank 

EDRTM Environmental Data Resources Trademarked

EGE Eagle County Regional Airport

EIS Extraction internal standards

ELAP Environmental Laboratory Accreditation Program

EM Engineer Manual

EPA U.S. Environmental Protection Agency

ERWVFA Eagle River Watershed Valley-Fill Aquifer

FAA Federal Aviation Administration

FB Field blank

FedEx Federal Express

ft Foot (feet)
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC vii

FTA Fire training area

HAATS High Altitude Aviation Training Site

HAZMAT Hazardous materials

HDPE High-density polyethylene

HFPO-DA Hexafluoropropylene oxide dimer acid

IDW Investigation-derived waste

ITRC Interstate Technology Regulatory Council

GA General Aviation

LC/MS/MS Liquid chromatography tandem mass spectrometry

LCS Laboratory control sample 

LCSD Laboratory control sample duplicate

LOQ Limit of quantification

MIL-SPEC military specification

MS Matrix spike

MSD Matrix spike duplicate

NELAP National Environmental Laboratory Accreditation Program 

ng/L Nanogram(s) per liter

NOAA National Oceanic and Atmospheric Administration

NWIS USGS National Wetland Information System

OSD Office of the Secretary of Defense

OWS Oil-water separator 

PA preliminary assessment

PFAS per- and polyfluoroalkyl substances

PFBS perfluorobutanesulfonic acid

PFHxS perfluorohexanesulfonic acid

PFNA perfluorononanoic acid

PFOA perfluorooctanoic acid

PFOS perfluorooctanesulfonic acid

PID photoionization detector

PVC polyvinyl chloride

QA Quality assurance

QAPP Quality Assurance Project Plan

QC Quality control

QSM Quality Systems Manual

RI Remedial investigation 

RPD Relative percent difference
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC viii

SI Site Inspection

SL Screening level

TOC Total organic carbon

TPP Technical Project Planning

UFP Uniform Federal Policy 

USACE U.S. Army Corps of Engineers

USDA U.S. Department of Agriculture

USDA U.S. Department of Agriculture

USFW U.S. Fish and Wildlife Service

USGS U.S. Geological Survey

VVJC Vail Valley Jet Center

Wood Wood Environment & Infrastructure Solutions, Inc. 

WSP WSP USA Environment & Infrastructure Inc.

WWTP Wastewater treatment plant
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC ES-1

EXECUTIVE SUMMARY

The Army National Guard (ARNG) G-9 is performing Preliminary Assessments (PAs) and Site 

Inspections (SIs) at ARNG facilities nationwide based on the current or potential historical use of 

per- and polyfluoroalkyl substances (PFAS) with a focus on the six compounds presented in the 

memorandum regarding Investigating Per- and Polyfluoroalkyl Substances within the 

Department of Defense Cleanup Program (Assistant Secretary of Defense, 2022) from the Office 

of the Secretary of Defense (OSD) dated 6 July 2022. The six compounds listed in the July 2022 

OSD memorandum include perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid 

(PFOA), perfluorobutanesulfonic acid (PFBS), perfluorononanoic acid (PFNA), 

perfluorohexanesulfonic acid (PFHxS), and hexafluoropropylene oxide dimer acid (HFPO-DA)1

. 

These compounds are collectively referred to as “relevant compounds” throughout the document, 

and the applicable screening levels (SLs) are provided below in Table ES-1. 

The PA identified three Areas of Interest (AOIs) where PFAS-containing materials may have 

been used, stored, disposed, or released historically (see Table ES-2 for AOI locations). The

objective of the SI is to identify whether there has been a release to the environment from the 

AOIs identified in the PA and determine whether further investigation is warranted, a removal 

action is required to address immediate threats, or no further action is required based on SLs for

the relevant compounds. This SI was completed at the High Altitude Aviation Training Site

(HAATS) in Gypsum, Colorado and determined further evaluation is warranted for AOI 1: 

Parking Apron/Taxiway and AOI 2: HAZMAT Storage Area. No further action is warranted for

AOI 3: Building 1214. HAATS will also be referred to as the “Facility” throughout this 

document. 

The Facility, operated by the Colorado ARNG (COARNG), encompasses approximately 20

acres leased from the Eagle County Regional Airport (EGE). The Facility is located at 315 N 

Airport Road, Gypsum, Colorado, which is north of the EGE airfield. The Facility consists of 

hangar space, classrooms, administrative areas, hazardous material storage, a parking apron and 

taxiway, and is designed to train military pilots in high altitude mountainous terrain. The Facility 

and surrounding airport property are zoned as a planned unit development (AMEC Earth and 

Environmental, Inc., [AMEC], 2010; AECOM, 2020).

The PA identified three AOIs for investigation during the SI phase. SI sampling results from the 

three AOIs were compared to OSD SLs. Table ES-2 summarizes the SI results for each AOI.

Based on the results of this SI, further evaluation under the Comprehensive Environmental 

Response, Compensation, and Liability Act (CERCLA) is warranted in a Remedial Investigation 

(RI) for AOI 1 and AOI 2. No further action is warranted for AOI 3.

1 Of the six PFAS compounds presented in the 6 July 2022 OSD memorandum, HFPO-DA (commonly referred to 

as GenX) was not included as an analyte at the time of this SI. Based on the conceptual site model (CSM) developed 

during the PA and revised based on SI findings, the presence of HFPO-DA is not anticipated at the facility because 

HFPO-DA is generally not a component of military specification (MIL-SPEC) aqueous film forming foam (AFFF) 

and based on its history including distribution limitations that restricted use of GenX, it is generally not a component 

of other products the military used. In addition, it is unlikely that GenX would be an individual chemical of concern 

in the absence of other PFAS.
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC ES-2 

Table ES-1. Screening Levels (Soil and Groundwater)

Analyte2

Residential

(Soil)

(μg/kg)1 

(0-2 feet bgs)

Industrial / Commercial

Composite Worker

(Soil)

(μg/kg) 1 

(2-15 feet bgs)

Tap Water

(Groundwater)

(ng/L)1 

PFOA 19 250 6

PFOS 13 160 4

PFBS 1,900 25,000 601

PFHxS 130 1,600 39

PFNA 19 250 6

Notes:

1. Assistant Secretary of Defense. July 2022. Risk Based Screening Levels in Groundwater and 

Soil using United States Environmental Protection Agency’s (EPA’s) Regional Screening 

Level Calculator. Hazard Quotient (HQ)=0.1. May 2022. 

2. Of the six PFAS compounds presented in the 6 July 2022 OSD memorandum, HFPO-DA 

(commonly referred to as GenX) was not included as an analyte at the time of this SI. Based 

on the CSM developed during the PA and revised based on SI findings, the presence of 

HFPO-DA is not anticipated at the facility because HFPO-DA is generally not a component 

of MIL-SPEC AFFF and based on its history including distribution limitations that 

restricted use of GenX, it is generally not a component of other products the military used. 

In addition, it is unlikely that GenX would be an individual chemical of concern in the 

absence of other PFAS.

Abbreviations: 

μg/kg = microgram(s) per kilogram

bgs = below ground surface

ng/L = nanogram(s) per liter

Table ES-2. Summary of Site Inspection Findings and Recommendations

AOI

Potential Release 

Area

Soil – 

Source Area

Groundwater – 

Source Area

Groundwater – 

Facility Boundary Future Action

1 Parking 

Apron/Taxiway

Proceed to RI

2 HAZMAT Storage 

Area

NA Proceed to RI

3 Building 1214 NA No further action

Legend:

 = Detected; exceedance of screening levels

 = Detected; no exceedance of screening levels

 = Not detected
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC 1-1

1. INTRODUCTION

1.1 PROJECT AUTHORIZATION

The Army National Guard (ARNG) G-9 is the lead agency in performing Preliminary 

Assessments (PAs) and Site Inspections (SIs) at ARNG facilities nationwide based on the current 

or potential historical use of per- and polyfluoroalkyl substances (PFAS) with a focus on the six 

compounds presented in the memorandum regarding Investigating Per- and Polyfluoroalkyl 

Substances within the Department of Defense Cleanup Program (Assistant Secretary of Defense, 

2022) from the Office of the Secretary of Defense (OSD) dated 6 July 2022. The six compounds 

listed in the July 2022 OSD memorandum are referred to as “relevant compounds” throughout 

this document and include perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), 

perfluorobutanesulfonic acid (PFBS), perfluorononanoic acid (PFNA), perfluorohexanesulfonic 

acid (PFHxS), and hexafluoropropylene oxide dimer acid (HFPO-DA)1. The ARNG performed 

this SI at the High Altitude Aviation Training Site (HAATS) in Gypsum, Colorado. The High

Altitude Aviation Training Site is also referred to as the “Facility” throughout this document. 

The SI project elements were performed in accordance with the Comprehensive Environmental 

Response, Compensation, and Liability Act (CERCLA) (U.S. Environmental Protection Agency 

[EPA] 1980), as amended, the National Oil and Hazardous Substances Pollution Contingency 

Plan (40 Code of Federal Regulations Part 300; EPA 1994), and in compliance with U.S. 

Department of the Army (DA) requirements and guidance for field investigations.

1.2 SITE INSPECTION PURPOSE

A PA was performed at the High Altitude Aviation Training Site (AECOM Technical Services, 

Inc. [AECOM] 2020) that identified three Areas of Interest (AOIs) where PFAS-containing 

materials may have been used, stored, disposed, or released historically. The objective of the SI 

is to identify whether there has been a release to the environment from the AOIs identified in the 

PA and determine whether further investigation is warranted, a removal action is required to 

address immediate threats, or no further action is required based on screening levels (SLs) for the 

relevant compounds.

1 Of the six PFAS compounds presented in the 6 July 2022 OSD memorandum, HFPO-DA (commonly referred to as 

GenX) was not included as an analyte at the time of this SI. Based on the conceptual site model (CSM) developed 

during the PA and revised based on SI findings, the presence of HFPO-DA is not anticipated at the facility because 

HFPO-DA is generally not a component of military specification (MIL-SPEC) aqueous film forming foam (AFFF) 

and based on its history including distribution limitations that restricted use of GenX, it is generally not a component 

of other products the military used. In addition, it is unlikely that GenX would be an individual chemical of concern 

in the absence of other PFAS.
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC 1-2

This page intentionally left blank
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC 2-1

2. FACILITY BACKGROUND

2.1 FACILITY LOCATION AND DESCRIPTION

The HAATS property encompasses approximately 20 acres leased from the Eagle County

Regional Airport (EGE) for Colorado ARNG (COARNG) use in the town of Gypsum, within 

Eagle County, Colorado (Figure 2-1). The Facility includes hangar space, classrooms, 

administrative areas, hazardous material [HAZMAT] storage, a parking apron and taxiway, and 

is designed to train military pilots in high altitude mountainous terrain. The Facility and 

surrounding airport property are zoned as a planned unit development (AMEC Earth and 

Environmental, Inc. [AMEC], 2010; AECOM, 2020).

Starting in approximately 1990, the COARNG HAATS Facility originally operated out of

Building 1213A. Building 1213A was constructed in the 1970s and was used as the main hangar

for the Mountain Flying Service until the building was leased to the COARNG. Construction on

the current Facility (which includes Building 1214, HAZMAT Storage, and the current flight

ramp and parking apron/taxiway) began in 2011 and was completed in 2013. In 2013, the 

COARNG moved operations to Building 1214, which serves as the COARNG HAATS main

hangar. After moving operations to the new Facility, Building 1213A was transferred to the Vail

Valley Jet Center (VVJC), and the COARNG ceased to maintain or operate the building 

(AECOM, 2020).

2.2 FACILITY ENVIRONMENTAL SETTING

HAATS and the area surrounding the larger EGE complex are a mix of industrial and

commercial properties, undeveloped land, agricultural land, and residential areas. The Eagle

River is located approximately 0.5 miles north of the Facility and flows west, and Highway 6 is 

located approximately 400 feet (ft) north of the Facility. The Facility sits within the Eagle River 

Valley on the western slope of the Colorado Rocky Mountains. Topography across the Facility

has been graded to drain to the northwest, and the greater area surrounding the Facility generally 

slopes northwest towards the Eagle River (AMEC, 2010; AECOM, 2020).

Most of the Facility is paved with asphalt or concrete, with the exception of some gravel and 

grassy areas surrounding the improved portions of the Facility. The HAATS property is bounded 

on the north side by a chain-link fence. Sanitary sewer service and potable water are provided to 

the Facility by the Town of Gypsum (AECOM, 2020).

The adjoining properties to the east, west, and south are all included within the EGE, which is 

zoned as a planned unit development. The VVJC Maintenance Hangar, which is the former 

location of the COARNG HAATS, is located immediately to the east. The property to the west 

includes the air traffic control tower. The runway and taxiways are located to the south of the 

Facility. The EGE commercial terminal is located further to the south, across the airfield. The 

property to the north, between the Facility and Highway 6, is zoned as industrial (AMEC, 2010; 

AECOM, 2020). It is currently undeveloped and is being used as a gravel mine. 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC 2-2

2.2.1 Geology

According to the 1978 Geologic Map of the Leadville Quadrangle compiled for the U.S.

Geological Survey (USGS), the primary geologic unit occurring in the vicinity of the Facility is 

the unconsolidated gravel and alluvium deposited as stream, terrace, and outwash material during 

the Quaternary Period (USGS, 1978; AECOM, 2020). The much older Eagle Valley Evaporite, a

series of gypsum, anhydrite, and interbedded siltstone and dolomite, make up the valley walls

not far from the Facility and likely lie beneath the unconsolidated surficial deposits at the 

Facility (AECOM, 2020).

Based on soil survey data published by the US Department of Agriculture (USDA) Natural

Resources Conservation Service, the primary soil type at the subject property is the Dotsero

sandy loam, which forms on terraces and toes of mountain slopes through the weathering of 

colluvium derived from basalt and other igneous rocks. The Dotsero sandy loam forms with 1 to 

12 percent (%) slopes and is typically well drained with moderate infiltration rates and high 

conductivity. Runoff is classified as low, and the frequency of flooding or ponding is low to 

none. The depth to the water table in the soil type is greater than 80 inches (USDA, 2019;

AECOM, 2020).

During the SI, well graded gravel with sand and silt was observed as the dominant lithology of 

the unconsolidated soils below the Facility, encountered below 10 to 18.5 ft below ground 

surface (bgs), with interbedded layers of clay, with variable amounts of silt and sand, and silty 

sand. The rounded to subangular gravel was comprised of sedimentary and igneous rocks and

included rock up to 15 centimeters in diameter. The upper lithologies consisted of organic soils 

with variable amounts of sand and lean clay with sand. Bedrock was recovered at one boring

(from 103 ft bgs), HAATS-03, and determined to be mudstone with quartz veins. The borings 

were completed at depths between 80 and 120 ft bgs. Samples for grain analyses were collected

at three locations, AOI01-05, AOI02-01, and AOI03-01, and analyzed via American Society for 

Testing and Materials (ASTM) Method D-422. The results from samples collected within the 

dominant lithology show sand range from 31.1% to 86.9%, silt from 5% to 60.7%, gravel from 

0% to 14.5%, and clay from 0.6% to 8.2%. These results underrepresent gravel in the lithology 

due to the size of gravel encountered and the packing of soil in sample jars for shipment. Results 

from an upper lithology logged as lean clay with sand report silt at 37.8%, sand at 31.7%, clay at 

18.87%, and gravel at 11.7%. These results and Facility observations are consistent with the 

reported depositional environment of the region. Boring logs are presented in Appendix E and 

grain size results are presented in Appendix F.

2.2.2 Hydrogeology

The groundwater flow direction in the vicinity of the Facility is to the northwest due to

topography and the influence of the Eagle River, as shown in Figure 2-2. Based on the 

preliminary data review conducted for this SI through the USGS National Wetland Information 

System (NWIS), the depth to groundwater in the vicinity of the Facility varies from 25 to 117 ft 

bgs. 

The Town of Gypsum overlies the Eagle River watershed valley-fill aquifer (ERWVFA). The

ERWVFA is an unconfined aquifer found within the alluvial deposits along the Eagle River and
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC 2-3

its tributaries, starting near the town of Vail, CO and heading west to Dotsero, CO (USGS, 2009; 

AECOM, 2020). Being unconfined, recharge of the aquifer across HAATS occurs through direct

infiltration of precipitation and/or irrigation and drainage ditch water. Deep groundwater at

HAATS is found in bedrock aquifers comprised of the hydrogeologic units associated with the

Eagle Basin-Central Colorado Trough. The uppermost group includes the Weber Aquifer,

Maroon-Minturn Aquifer, and the Belden-Molas confining unit. The primary water-bearing rock

type in this group is sandstone (Barkmann et al., 2020; AECOM, 2020).

Potable and non-potable water is provided to EGE and its tenants through the Town of Gypsum. 

There are no water wells located at the Facility. Potable water is used for drinking water at 

HAATS, and non-potable water is strictly used for irrigation. The water is owned by the Town of 

Gypsum and stored in various large water tanks throughout the town. The Town of Gypsum 

2022 Drinking Water Quality Report (covering data for calendar year 2021) lists four sources of 

water; Eagle River (surface water intake), Little Gypsum Creek (surface water intake), Mosher 

Springs Pond (surface water intake), and Gypsum Creek (surface water intake, Town of Gypsum, 

2022). Most of the known intake points associated with Mosher Springs and Gypsum Creek 

would be unaffected by potential PFAS releases at the HAATS Facility because they are located

upstream from the creek’s confluence with the Eagle River. The Norgaard Water Treatment 

Plant and associated intake point is located on Gypsum Creek upstream of the confluence of 

Gypsum Creek and Eagle River. Based on the synoptic water level measurements made during 

the SI, the intake point is likely cross-gradient of the Facility. The locations of the Eagle River

intake and the T2 well (identified in the 2016 town water quality report), are unknown (AECOM,

2020).

The airport receives its water through several water mains located on the south side of the

airfield to support the commercial terminal area and on the north side of the airfield to support 

the HAATS and GA hangars (EGE, 2014). As part of the PA, an Environmental Data Resources 

(EDRTM) well search was conducted within a 1-mile radius surrounding the Facility. Using 

additional online resources, such as state and local GIS databases, wells were researched to a 4-

mile radius of the Facility. Numerous wells of various use exist in all directions surrounding the 

Facility (AECOM, 2020). Based on the synoptic water level measurements made during the SI, 

there are three commercial wells that are potentially downgradient of the Facility. One of the 

commercial wells is located on the property just north of the facility that is currently being used 

to mine gravel. Commercial well permits allow for commercial use that includes drinking and 

sanitation facilities inside a business (Colorado Division of Water Resources, 2023). 

No PFAS analyses results for the Town of Gypsum public water system were available. Based

on information available, it does not appear that the Town of Gypsum public water system was

included in the EPA Unregulated Contaminant Monitoring Rule 3 (UCMR3) program.

Additionally, the Town of Gypsum 2022 Drinking Water Quality Report (covering data for

calendar year 2021) does not include results for the analysis of PFAS.

Depths to water measured in July 2022 during the SI ranged from 75.04 to 94.24 ft bgs. 

Groundwater elevation contours from the SI are presented on Figure 2-5 and indicate the 

groundwater flow direction primarily to the northwest, toward the Eagle River. 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC 2-4

2.2.3 Hydrology

The Facility is located within the Eagle River Watershed. Surface water at HAATS is limited to 

drainage ditches that intermittently contain water. There are several nearby surface water areas 

designated by the US Fish and Wildlife Service (USFWS) National Wetlands Inventory 

(USFWS, 2019; AECOM, 2020), Figure 2-4. The “Chattfield and Bartholomew Ditch” is 

designated as a freshwater emergent wetland or as riverine habitat, depending on location and

encroaches on the southern and western boundaries of the Facility. The “CKP Ditch” is also 

designated as both freshwater emergent wetland and riverine habitat depending on location, and 

it encroaches on the northern and western boundaries of the Facility as well (USFWS, 2019; 

AECOM, 2020).

The HAATS 2017 Spill Prevention, Control, and Countermeasure Plan indicates that surface

runoff generally flows to the northwest, with some local flow to the southwest, on the Flight

Ramp, immediately south of Building 1214 (COARNG, 2017; AECOM, 2020). As-built utility

drawings show stormwater inlets on the north side of Building 1214 that discharge to a low point 

at the north Facility boundary. Another stormwater inlet is located in a low point north of the 

apron which flows toward a ditch on the east side of the apron. An oil-water separator (OWS),

associated with the sanitary sewer, is located near the northeast corner of Building 1214. The

stormwater system ultimately flows north towards the Eagle River (COARNG, 2017; AECOM,

2020). The storm sewer and Facility drainage information are shown on Figure 2-4.

Stormwater runoff across the airport property drains to the north and west, into the Eagle River,

towards the Town of Gypsum. The EGE stormwater system is composed of open channels and

pipes directing the flow of water, and drainage basins to collect runoff. The majority of the

airport drains to the northwest, while the eastern edge of the airfield drains east before turning

north towards the Eagle River (EGE, 2014; AECOM, 2020).

Sanitary services are provided through the Town of Gypsum, Public Works Department.

Wastewater is collected and processed through the Town’s nitrification/de-nitrification

wastewater treatment plant (WWTP) located approximately 2.6 miles west of the Facility.

Sludge disposal is performed by a third-party contractor (EGE, 2014; AECOM, 2020). 

Flood Insurance Rate Maps for Eagle County and the region immediately surrounding the airport

indicate that no flood zones are located within airport property. The nearest flood zone is north

of the airport by approximately one-half mile (EGE, 2014; AECOM, 2020).

2.2.4 Climate

Data from the EGE weather station indicate that the annual average temperature between 1981

and 2010 was 44.7 degrees Fahrenheit (oF). The warmest months are July and August, with 

normal daily average temperatures of 67.2oF and 66.0oF, respectively. January is the coldest 

month, with an average temperature of 21.3oF. Average annual precipitation measured from 1981 

to 2010 at the airport was 11.31 inches, with the most rain occurring August through September 

(National Oceanic and Atmospheric Administration [NOAA], 2020; AECOM, 2020). The

average annual snowfall for EGE, as reported by the Western Regional Climate Center, is 48
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC 2-5

inches. The majority of snowfall occurs between December and January (Western Regional 

Climate Center, 2020; AECOM, 2020). 

2.2.5 Current and Future Land Use

HAATS is the primary training center for ARNG helicopter pilots conducting high-altitude

flying in mountainous terrain and/or high temperatures. HAATS is the only Department of

Defense Aviation Training site for high altitude power management environmental training. The

Facility trains over 400 aircrews annually from all branches and components for the National

Guard Bureau and Fort Rucker as well as active Army, Army Reserves, and international 

military aircrews. The Facility is fenced as part of EGE airport property and access to parking

apron, taxiway, and runway is restricted by gate to Transportation Security Administration

trained badged personnel. The Facility was recently expanded to add entirely new features and 

amenities, with the ability for continued expansion. Future use of the HAATS Facility is 

anticipated to remain the same (AECOM, 2020).

EGE is the major conduit for commercial airline passengers to and from the Vail Valley. The

airport’s location provides access to the heart of the Colorado Rocky Mountains and is a short

drive to the Vail & Beaver Creek Ski Resorts, making EGE a primary gateway for tourists during

both winter and summer seasons. Future use of EGE is anticipated to remain the same (EGE, 

2014; AECOM, 2020).

2.2.6 Sensitive Habitat and Threatened/Endangered Species

A wildlife survey has not occurred at the Facility, and the Facility does not have any significant 

areas of habitat. The following species have not been identified at the Facility but may be present 

in the surrounding area.

The following species are listed as federally endangered, threatened, proposed, and/or candidate 

species in Gypsum, Colorado (USFWS, 2022):

Birds: Mexican Spotted Owl, Strix occidentails lucida (threatened), Yellow-billed Cuckoo, 

Coccyzus americanus (threatened)

Birds (migratory presence from June to early July): Bald Eagle, Haliaeetus leucocephalus 

(vulnerable), Black Swift, Cypseloides niger (Bird of conservation concern [BCC]), Brown 

Capped Rosy-finch, Leucosticte australis (BCC), California Gull, Larus californicus (BCC), 

Cassin’s Finch, Carpodacus cassinii (BCC), Clark’s Nutcracker, Nucifraga columbiana (BCC), 

Evening Grosbeak, Coccothraustes vespertinus (BCC), Lewis’s Woodpecker, Melanerpes lewis 

(BCC), Olive-sided Flycatcher, Contopus cooperi (BCC), Pinyon Jay, Gymnorhinus 

cyanocephalus (BCC), Virginia’s Warbler, Vermivora virginiae (BCC), Western Grebe, 

aechmophorus occidentalis (BCC)

Fishes: Bonytail, Gila elegans (endangered), Colorado Pikeminnow, Ptychocheilus lucius 

(endangered), Humpback Chub, Gila cypha (threatened), Razorback Sucker, Xyrauchen texanus

(endangered)
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC 2-6

Flowering Plants: Ute Ladies’-tresses, Spiranthes diluvialis (threatened)

Insects: Monarch Butterfly, Danaus plexippus (candidate)

Mammals: Canada Lynx, Lynx canadensis (threatened), Gray Wolf, Canis lupus (endangered)

2.3 HISTORY OF PFAS USE

Three AOIs were identified in the PA where aqueous film-forming foam (AFFF) may have been 

used, stored, disposed, or released historically at the Facility, although there are no known PFAS 

releases since the construction of the Facility in 2013. Five potential release areas were grouped 

into three AOIs based on preliminary findings and presumed groundwater flow directions. These 

AOIs were identified as the Parking Apron/Taxiway, HAZMAT Storage Area, and Building 

1214. A description of each AOI is presented in Section 3. 
Facility Boundary

3

P:\Project\AMEC Inter-Office Projects\3031200026 HAATS\3031200026 HAATS\2-1_FacilityLocationMap-1.mxd

Army National Guard Site Inspections

High Altitude Aviation Training Site

Gypsum, Colorado

Figure 2-1

Facility Location

CO

Data Sources: 

ESRI 2020

AECOM 2020

Date:......................JANUARY 2023

Prepared By:............................WSP

Prepared For:.......................USACE

Projection:.........NAD 83 StatePlane

^_

Facility Data

Facility Boundary
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC 2-8

This page intentionally left blank
Facility Boundary

P:\Project\AMEC Inter-Office Projects\3031200026 HAATS\3031200026 HAATS\2-2_FacilityTopography-1.mxd

^_ CO

Army National Guard Site Inspections

High Altitude Aviation Training Site

Gypsum, Colorado

Figure 2-2

Facility Topography

Data Sources: 

ESRI 2020

AECOM 2020

Date:......................JANUARY 2023

Prepared By:............................WSP

Prepared For:.......................USACE

Projection:.........NAD 83 StatePlane

Facility Data

Facility Boundary

3

0 4,000

Feet
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC 2-10

This page intentionally left blank
!P

A@

!P

!P

!P

A@ A@

A@

A@

!P

A@

A@ A@

A@

A@

A@ !P

A@

A@

A@ A@ A@

A@

!P

A@ A@

A@

!P A@ A@

A@A@ A@

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P !P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P!P

!P

!P

!P

!P

!P

!P

!P!P !P

!P

!P

!P

!P

!P

!P

!P

!P !P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P!P

!P

!P

!P

A@

!P

!P

!P

!P

!P

!P

!P!P !P

!P

!P

!P

!P

!P!P!P !P

!P!P

A@P !P

!P

!P

!P !P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P

A@A@

A@

!P

P

A@

A@

!P

!P

!P

!P

A@

McHatten Creek

Gypsum

Creek

Cottonwood Creek

Eagle River

Alkali Creek

Alkali Creek

Eagle River

Spring Creek

0 4,000

Feet

3 P:\Project\AMEC Inter-Office Projects\3031200026 HAATS\3031200026 HAATS\2-3_GroundwaterFeatures.mxd

Facility Data

!P Commercial

!P Domestic

!P Industrial

!P Irrigation

A@ Monitoring/Sampling

4-Mile Radius

FacilityBoundary

Streams And Rivers

Water Bodies

Lower Gypsum Creek WaterShed

Outlet Eagle River Water Shed

Spring Creek-Eagle River Water Shed

Date:.............................APRIL 2023

Prepared By:............................WSP

Prepared For:.......................USACE

Projection:.........NAD 83 StatePlane

Data Sources: 

ESRI 2020

AECOM 2020

Army National Guard Site Inspections

High Altitude Aviation Training Site

Gypsum, Colorado

Figure 2-3

Groundwater Features

^_ CO

Norgaard Water

Treatment Plant
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC 2-12

This page intentionally left blank
!(

!(

")

")

") ") ")

!(

!(!(

Facility Boundary

CKP Ditch

Chattfield

and Bartholomew Ditch

Stremme and Gates Ditch

0 400

Feet

3

P:\Project\AMEC Inter-Office Projects\3031200026 HAATS\3031200026 HAATS\2-4_SurfaceWaterFeatures.mxd

Facility Data

") Inlet

!( Manhole

Ditches

Surface Water Flow Direction

Storm Sewer

Drainage Swale

Streams And Rivers

Facility Boundary

Army National Guard Site Inspections

High Altitude Aviation Training Site

Gypsum, Colorado

Figure 2-4

Surface Water Features

^_ CO

Date:......................JANUARY 2023

Prepared By:............................WSP

Prepared For:.......................USACE

Projection:.........NAD 83 StatePlane

Data Sources: 

ESRI 2020

AECOM 2020
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC 2-14

This page intentionally left blank
!? !?

!?

!?

!?

!?

!?

!?

!?

!?

!?

6350

6360

6365

6370

6375

6355

Facility Boundary

AO101-05

DRY

AO101-01

DRY

AO103-01

6348.04

HAATS-02

6373.26

HAATS-01

6376.11

HAATS-03

6378.69

AO101-02

6371.04

AO101-04

6371.34

AO101-03

6370.43

AO102-01

6356.04

AO102-02

6351.63

0 300

Feet

3 P:\Project\AMEC Inter-Office Projects\3031200026 HAATS\3031200026 HAATS\2-5_GWElevationContours.mxd

Facility Data

!? Groundwater Wells

Groundwater Flow Direction

Groundwater Elevation Contour

Facility Boundary

Army National Guard Site Inspections

High Altitude Aviation Training Site

Gypsum, Colorado

Figure 2-5

Groundwater Elevations

Date:.............................APRIL 2023

Prepared By:............................WSP

Prepared For:.......................USACE

Projection:.........NAD 83 StatePlane

Data Sources: 

ESRI 2020

AECOM 2020

^_ CO
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

 

EA Engineering, Science, and Technology, Inc., PBC 2-16

This page intentionally left blank
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 3-1

3. SUMMARY OF AREAS OF INTEREST

The PA evaluated areas where PFAS-containing materials may have been used, stored, disposed, 

or released historically. Based on the PA findings, five potential release areas were identified at 

HAATS and grouped into three AOIs, identified as AOI 1 Parking Apron/Taxiway, AOI 2 

HAZMAT Storage Area, and AOI 3 Building 1214. The AOIs are shown on Figure 3-1.

3.1 AOI 1 – PARKING APRON/TAXIWAY

The Facility parking apron is located southeast of Building 1214 and is circumscribed by a 

taxiway. The apron is used for aircraft staging and maintenance. According to those interviewed 

during the PA, no incidents requiring AFFF use have occurred on the parking apron. Four TriMaxTM wheeled mobile fire extinguishers containing AFFF are staged on the taxiway on the 

north side of the parking apron. According to Facility personnel, the Tri-MaxTM units are in good

condition, have no history of leaks or spills, have never been used at the Facility, and are 

inspected monthly for integrity; however, based on the corrosive nature of AFFF and the storage 

of the Tri-MaxTM units outside, it is possible that AFFF may have been released to the parking 

apron area. Monthly inspection records for the Tri-MaxTM extinguishers were not made available 

for inclusion in the PA report. The type and concentration of AFFF stored within the Tri-MaxTM

extinguishers are unknown (AECOM, 2020).

Occasionally, water salutes are performed for retiring pilots on the taxiway on the south side of

the parking apron. The salutes involve EGE Fire Department firetrucks spraying water across the

taxiway while a grounded aircraft is taxiing. The water sprayed during the salutes likely travels

across the taxiway and parking apron on the HAATS property. Only water is sprayed during the

water salutes; however, it is possible the water is sprayed from EGE firetrucks that also store

AFFF (AECOM, 2020).

Due to the corrosive nature of AFFF and the storage of the Tri-MaxTM units outside, and the

performance of water salutes across the Facility’s southern taxiway, the parking apron was

identified as an AOI (AECOM, 2020).

3.2 AOI 2 – HAZMAT STORAGE AREA

HAZMATs stored by the COARNG at the Facility are kept in the HAZMAT storage area located 

on the north side of Building 1214. The area is also used for the storage of waste and is the 

location of an aboveground storage tank containing diesel fuel. According to Facility personnel, 

one Tri-MaxTM 30 Cold Compressed Air Foam (CAF) fire extinguisher containing AFFF is 

stored in the HAZMAT storage area, however, the Tri-MaxTM unit has not been used. The TriMaxTM unit is in good condition, has no history of spills or leaking, and is inspected monthly for 

integrity; however, based on the corrosive nature of AFFF and the storage of the Tri-MaxTM unit 

outside, it is possible that AFFF may have been released to the HAZMAT storage area. TriMaxTM unit inspection records were not available for inclusion in the PA report. No emergencies 

requiring the use of the Tri-MaxTM unit have occurred in the HAZMAT storage area, or 

anywhere else on the Facility. Additionally, COARNG personnel do not train with the TriMaxTM units. The Eagle Fire Department responds to emergencies at the Facility. The type and 

concentration of AFFF stored within the unit is unknown. A fire hydrant is also located adjacent 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 3-2

to the HAZMAT storage area for use in response to an emergency. Due to the corrosive nature of 

AFFF and the storage of the Tri-MaxTM fire extinguisher outside, the HAZMAT storage area was 

identified as an AOI (AECOM, 2020).

3.3 AOI 3 – BUILDING 1214

Building 1214 is located on the western end of the Facility. Construction of Building 1214 was 

completed in 2013, and the building serves as the HAATS main hangar and includes classroom 

areas, administrative office areas, and billets. The building is constructed with an AFFF fire 

suppression system that contains Buckeye Premium 3% Military Specification AFFF

concentrate. Although the Safety Data Sheet for this AFFF product indicates that it does not

contain PFOS or PFOA, it is unknown whether it may contain or degrade into other PFAS

compounds. The size of the AFFF tank serving the fire suppression system is unknown. A 55-

gallon drum containing the same AFFF concentrate product is also stored within Building 1214. 

According to Facility personnel, whose collective tenure span the entire history of Building 

1214, the fire suppression system has never been tested in a manner that released AFFF, nor has 

it been used in response to an emergency. The fire suppression system is tested annually in an 

enclosed manner that recycles the AFFF concentrate without a release. Regular maintenance of 

the alarm, pumps, and valves is also conducted without release (AECOM, 2020).

Fueling of aircraft stored in Building 1214 occurs on the Flight Ramp south of Building 1214.

Facility personnel stated that fuel spills in the area are uncommon, and that AFFF is not used as a

precautionary measure in response to fuel spills. The EGE Fire Department responds to

emergencies at the Facility, but no emergencies have occurred at Building 1214 requiring 

emergency response (AECOM, 2020).

Floor drains in Building 1214 connect to municipal sanitary sewers. Surface runoff at Building 

1214 flows generally to the northwest, except on the southern side of the building, where it flows 

southwest. Although AFFF is stored indoors at Building 1214, and the fire suppression system 

undergoes regularly scheduled maintenance, the building has been identified as an AOI due to 

the storage of materials that potentially contain PFAS (AECOM, 2020).

Facility personnel stated during the PA interviews that annual fire training is performed near the 

southeastern corner of Building 1214 on the Flight Ramp, adjacent to the parking apron/taxiway. 

The fire training involves the lighting of diesel fuel in a drip pan and the subsequent

extinguishing of the flames using ABC dry chemical handheld fire extinguishers. According to

interviewees whose collective tenure span the entire history of the new Facility (2013- present), 

no AFFF has ever been used during the annual fire training. Records are not kept documenting 

the annual training. Mobile Tri-MaxTM 30 Cold CAF fire extinguishers that contain AFFF are 

stored at the Facility, but Facility personnel stated that they have never been used for fire training 

purposes (AECOM, 2020). Based on this information, the PA report did not identify the flight 

ramp fire training area (FTA) as a potential PFAS release area (AECOM, 2020). However, due 

to the historic use of AFFF at FTAs in general, it was incorporated into AOI 3.
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 3-3

3.4 ADJACENT SOURCES

Several potential off-Facility sources of PFAS adjacent to the Facility, not under the control of 

the COARNG, were identified during the PA through interviews, review of the Environmental 

Data ResourcesTM report for a 1-mile radius surrounding the Facility, and historical document

review. 

3.4.1 Vail Valley Jet Center

EGE has one fixed base operator on the airfield, the VVJC. The VVJC main hangar is located

south of the runway and east of the EGE commercial terminal, upgradient of the Facility.

Services performed at the VVJC include aircraft line service, apron parking, hangar storage

space, on-site catering, and flight planning. The VVJC also provides aircraft fueling along with

aircraft maintenance and deicing. The VVJC owns and operates two aboveground fuel storage

tanks on the north airfield to support its fueling services, which includes fueling for HAATS 

aircraft operations. The VVJC also occupies the former HAATS, Building 1213A. The VVJCs 

operation of Building 1213A began in 2013, when construction of the current Facility was 

complete. Building 1213A was previously occupied by the COARNG and served as the former

HAATS between 1990 and 2013. The VVJC uses Building 1213A for additional hangar space 

(AECOM, 2020).

Information provided from an interview with an EGE Fire Department firefighter indicated that

Building 1213A had an AFFF bladder system that was not used or tested. During interviews 

conducted as part of the PA, COARNG personnel stated that no known AFFF was ever used or 

stored in the building. The tenure of COARNG personnel interviewed span the use of both the 

current and former Facility over 32 years (AECOM, 2020).

It is unknown whether the main VVJC hangar space located on the south side of the runway uses

an AFFF suppression system, or whether AFFF has ever been used or stored in the area in

general. Due to the lack of available data surrounding both VVJC areas, they are considered

potential PFAS release areas (AECOM, 2020).

3.4.2 Eagle County Regional Airport

EGE is publicly owned and consists of 632 acres that operate as a commercial airport. Its airfield 

configuration consists of one active runway, designated as Runway 7/25, that is positioned 

nearly east/west, immediately upgradient of the Facility. The asphalt taxiway system consists of 

one full length parallel taxiway on the south side of Runway 7/25, one partial parallel taxiway on 

the north side, and several connector taxiways. There are several aprons serving different needs 

at EGE. Both the Commercial Aviation Apron and the General Aviation (GA) Apron for the

fixed base operators at the airport are located south of the runway. There are two aprons located

on the north side of Runway 7/25. These aprons include the COARNG apron, which supports the

Facility, as well as an additional GA Apron to the east of the Facility, serving the associated GA 

hangars and the VVJC (AECOM, 2020).

The EGE commercial terminal was constructed in 1996, but the runway was dedicated for GA
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 3-4

services in 1947. The terminal is located on the west end of the main Commercial Aviation

Apron. At the time of the PA, five airlines leased space throughout the terminal: American, 

Continental, Delta, United, and United Express (AECOM, 2020).

EGE has several hangars on the airfield. VVJC provides the majority of hangar space on the

main GA Apron with four hangars. There is also one additional privately-owned corporate

hangar on the east end of the main GA Apron. On the GA Apron north of the runway, there are

nine medium sized hangars that are either airport- or privately-owned. In addition to the hangars,

there are ten airport-owned, T-Hangar style aircraft storage units (AECOM, 2020).

Representatives of EGE were not interviewed as a part of the PA. As such, it is unknown

whether any of the EGE hangars store or use AFFF or any other known PFAS-containing

materials (AECOM, 2020).

In 2005, a Gates Learjet 35A crashed and came to rest in a shallow ravine approximately 331

feet north of the runway. The crash fire was responded to by EGE Fire Department. In 2017, a

private Cessna crashed onto a small road east of the EGE runway; it is unknown whether a fire 

occurred during the crash. It is unknown if AFFF was used in response to either of these crashes

(AECOM, 2020).

The EGE Fire Station 10, which is located on the south side of the EGE runway and west of the

commercial terminal, responds to emergencies at the airport and for airport tenants, including

COARNG. Due to the lack of data regarding responses to crashes on the EGE runway and

surrounding areas, and the propensity for runways to be used during nozzle testing and fire

training by airport fire departments, Runway 7/25 is considered a potential PFAS release area

(AECOM, 2020).

3.4.3 Eagle County Regional Airport Fire Department

The EGE Fire Station 10 is located south of the runway at the southwest corner of the EGE

Commercial Apron, upgradient of the Facility. The building was built in 1989 and serves as the

administrative offices for EGE staff, as well as the airport administration office, maintenance, 

and operations center. Maintenance on equipment occurs at the fire station inside the vehicle 

bays. There is additional storage for fire department equipment on the north airfield, in storage 

buildings; however, firefighters with the EGE Fire Department stated that Aircraft Rescue and 

Firefighting (ARFF) equipment has only ever been stored in the fire station on the south side of 

the runway (AECOM, 2020).

As a commercial airport, the EGE Fire Department must comply with FAA safety and

emergency requirements, including ARFF services. To comply with FAA ARFF requirements,

the EGE Fire Department has four active ARFF response vehicles for aircraft emergencies.

According to the 2014 EGE Master Plan, these vehicles include one 2006 Oshkosh Striker 3000,

one 1988 Oshkosh T-1500, one 1993 Oshkosh T-1500, and one 2004 Tote ARFF foam trailer

(EGE, 2014; AECOM, 2020).

According to interviewees, the EGE Fire Department trains in Denver, Colorado; however, it is

unknown whether the fire department has ever trained within the EGE airport property, or
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 3-5

whether it has ever been necessary to use AFFF in response to an emergency on EGE property.

According to the EGE master plan, the fire department performs vehicle maintenance at Fire

Station 10; however, it is unclear if any other maintenance, such as nozzle tests, are performed

elsewhere at the airport. Due to the likelihood that AFFF has been stored and/or released at the

fire station as a result of training and maintenance exercises, Fire Station 10 is considered a

potential PFAS release area (AECOM, 2020).

3.4.4 Gypsum Fire Protection District

The Gypsum Fire Protection District is a combination fire department comprised of full-time and

part-time personnel as well as volunteer firefighters serving the Town of Gypsum. The Gypsum

Fire Protection District fire station is located approximately two miles west of the Facility, in the 

Town of Gypsum, cross gradient of the Facility. It is unknown whether the fire department stores 

or uses AFFF during training or emergency response. Given the tendency for local fire 

departments to store AFFF for emergency purposes, it is possible AFFF is stored at the Gypsum 

Fire Protection District fire station. It is also unclear whether the fire department performs 

vehicle maintenance, such as nozzle tests, at the fire station. Due to the likelihood that AFFF has 

been stored and/or released at the fire station as a result of potential training and maintenance, 

the Gypsum Fire Protection District fire station is considered a potential PFAS release area 

according to the PA. Although the Gypsum Fire Protection District is identified in the PA as a 

potential adjacent source, the river potentially acts as a hydraulic barrier between the Facility and 

the Gypsum Fire Protection District, so it is unlikely that a release at the fire station would 

impact the Facility (AECOM, 2020).

3.4.5 Town of Gypsum Wastewater Treatment Plant

There are no WWTPs located at the Facility. The Town of Gypsum WWTP is the nearest 

WWTP and is located approximately 2.6 miles to the west, along the Eagle River. WWTPs are 

not usually a primary potential release area of PFAS, but sludges and liquids from areas of 

potential release that are treated at WWTPs may create a secondary source of contamination. No 

known PFAS releases have occurred at the Facility, but AFFF releases may have occurred 

elsewhere on the larger EGE property and could have resulted in the migration of PFAS in 

wastewater to the Town of Gypsum WWTP. If undocumented releases of AFFF have entered 

floor drains at the Facility, then it is possible the Facility has contributed to PFAS migration to 

and through the WWTP. The WWTP uses nitrification/de-nitrification technology to treat 

wastewater. Sludge generated at the WWTP is removed and disposed of by a third-party 

contractor. The location of disposed sludge is unknown. Due to the potential for AFFF releases 

to have occurred elsewhere on the EGE property and in the town of Gypsum, the WWTP is 

considered a potential PFAS release area. Although the WWTP is identified in the PA as a 

potential adjacent source, the river potentially acts as a hydraulic barrier between the Facility and 

the WWTP (AECOM, 2020).
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 3-6

This page intentionally left blank
A@ !P

A@ A@

A@

!P

A@ A@

A@

A@

A@

A@

A@ A@ A@

A@

!P

!(G

!(G

A@

A@

!P A@ A@

A@A@ A@

!P

!P

!P

!P

!P

!P

!P

!P

!(G

!P

!P

!P

!P

!P

!P !P

!P

!(PG

!P

!P !P !P

!P

!P

!(G !(G

!P !P

!(G

!(G !(G !(G

!(G

!P

!P

!P

!P

!P !P

!P

!P

!P

!P

!P

!(G

!P

!P !P

!P

!P

!P

A@

!P

!P

!P

!P

!P

!P

!P

!P

!P

!P !P !P !P !P

!P !P

A@!P

!P

!P

!P

!P !P

!P

!P

!P

!P

!P

!P!P

!P

!P

!P

!P

!P

A@A@

A@

A@

!P

A@

HAZMAT Storage

AOI 3

AOI 1

Vail Valley Jet Center- Parking Apron/Taxiway Building 1213A

Flight Ramp

EGE Fire

Station 10

EGE Commercial 

Terminal

Vail Valley

Jet Center

Vail Valley

Jet Center Hanger

Vail Valley

Jet Center Hanger

Vail Valley

Jet Center Hanger

Vail Valley

Jet Center Hanger

Gypsum Fire

Protection

District

Town of

Gypsum WWTP

Outlet Eagle

River

Watershed

Spring Creek-Eagle

River Watershed

Lower Gypsum

Creek

Watershed

AOI 2

Building 1214

Flight Ramp FTA

EGE Runway

7/25

0 2,000

Feet

3

P:\Project\AMEC Inter-Office Projects\3031200026 HAATS\3031200026 HAATS\3-1_AreaofInterest.mxd

Service Layer Credits: Source: Esri, Maxar, Earthstar Geographics, and the GIS User Community

Facility Data

Well Type

!P Domestic

!P Commercial

!P Industrial

!P Irrigation

A@ Monitoring/Sampling

!(G Municipal

Hydrology/Hydrogeology

River/Stream

Water Bodies

Facility Data

Potential PFAS Release

No Suspected Release

Area of Interest

Facility Boundary

Army National Guard Site Inspections

High Altitude Aviation Training Site

Gypsum, Colorado

Figure 3-1

Areas of Interest

Date:......................JANUARY 2023

Prepared By:............................WSP

Prepared For:.......................USACE

Projection:.........NAD 83 StatePlane

Data Sources: 

ESRI 2020

AECOM 2020

^_ CO
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 3-8

This page intentionally left blank
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 4-1

4. PROJECT DATA QUALITY OBJECTIVES

As identified during the Data Quality Objective (DQO) process and outlined in the SI Uniform 

Federal Policy (UFP)-Quality Assurance Project Plan (QAPP) Addendum (EA Engineering, 

Science, and Technology, Inc., PBC [EA]/ Wood Environment & Infrastructure Solutions, Inc.

[Wood], 2022), the objective of the SI is to identify whether there has been a release to the 

environment at the AOIs identified in the PA. For each AOI, ARNG determines if further 

investigation is warranted, a removal action is required to address immediate threats, or whether 

no further action is warranted. This SI evaluated groundwater and soil for the presence or 

absence of relevant compounds at each of the sampled AOIs.

4.1 PROBLEM STATEMENT

ARNG will recommend an AOI for remedial investigation (RI) if related soil and groundwater 

samples have concentrations of the relevant compounds above the OSD risk-based SLs. The SLs 

are presented in Section 6.1 of this report.

4.2 INFORMATION INPUTS

Primary information inputs for the SI include the following:

• The PA Report for HAATS (AECOM, 2020);

• Analytical data from groundwater and soil samples collected as part of this SI in 

accordance with the site-specific UFP –QAPP Addendum (EA/Wood, 2022); and

• Field data collected during the SI, including groundwater elevation and water quality 

parameters measured at the time of sampling.

4.3 STUDY BOUNDARIES

The scope of the SI was bounded horizontally by the property limits of the Facility (Figure 2-2). 

The scope of the SI was bounded vertically by the depth of temporary monitoring wells installed 

within groundwater, where encountered (maximum depth of 120 feet bgs). Off-facility sampling 

was not included in the scope of this SI. If future off-facility sampling is required, the proper 

stakeholders will be notified, and necessary rights of entry will be obtained by ARNG with 

property owner(s). Temporal boundaries were limited to the earliest available time field 

resources were available to complete the study.

4.4 ANALYTICAL APPROACH

Samples were analyzed by Eurofins, accredited under the Department of Defense (DoD)

Environmental Laboratory Accreditation Program (DoD ELAP; Accreditation Number 1.01) and 

the National Environmental Laboratory Accreditation Program (NELAP; Certificate Number 

021). Data were compared to applicable SLs within this document and decision rules as defined 

in the UFP-QAPP Addendum (EA/Wood, 2022). 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 4-2

4.5 DATA USABILITY ASSESSMENT

The Data Usability Assessment (DUA), which is provided in Appendix A, is an evaluation at the 

conclusion of data collection activities that uses the results of both data verification and 

validation in the context of the overall project decisions or objectives. Using both quantitative 

and qualitative methods, the assessment determines whether project execution and the resulting 

data have met installation specific DQOs. Both sampling and analytical activities are considered 

to assess whether the collected data are of the right type, quality, and quantity to support the 

decision-making (DoD 2019a, DoD 2019b, EPA 2017).

Based on the DUA, the environmental data collected during the SI were found to be acceptable 

and usable for this SI evaluation with the qualifications documented in the DUA and its 

associated data validation reports. While not all planned samples were collected due to field 

conditions (see Section 5.9), the data that was obtained allowed for an assessment of whether 

there had been a release to the environment at the three AOIs identified in the PA. These data are

of sufficient quality to meet the objectives and requirements of the UFP-QAPP (EA, 2020).
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 5-3

5. SITE INSPECTION ACTIVITIES

This section describes the environmental investigation and sampling activities that occurred as 

part of the SI. The SI sampling approach was based on the findings of the PA and was 

implemented in accordance with the following approved documents. 

• Final Preliminary Assessment Report, HAATS, Gypsum, Colorado, dated August

2020 (AECOM, 2020)

• Final Programmatic Uniform Federal Policy-Quality Assurance Project Plan,

Site Inspections for Per- and Polyfluoroalkyl Substances Impacted Sites, ARNG 

Installations, Nationwide, dated December 2020 (EA, 2020)

• Final Site Inspection Uniform Federal Policy-Quality Assurance Project Plan 

Addendum, HAATS, Colorado dated January 2022 (EA/Wood, 2022)

• Final Programmatic Accident Prevention Plan, Revision 1, dated November 2020

(EA, 2020)

• Accident Prevention Plan/Site Safety and Health Plan Addendum, HAATS, 

Gypsum, Colorado dated August 2021 (EA/Wood, 2021)

The SI field activities were conducted during two mobilizations to the Facility. The first 

mobilization was from 13 April to 14 April 2022. and consisted of utility clearance, hand 

auguring to a depth of 2 ft bgs and soil sample collection. The second mobilization 

occurred from 7 June to 14 July 2022 and consisted of additional utility clearance, 

rotosonic boring and soil sample collection, temporary monitoring well installation, grab 

groundwater sample collection, and land surveying. Field activities were conducted in 

accordance with the UFP-QAPP Addendum (EA/Wood, 2022), except as noted in 

Section 5.9.

The following samples were collected during the SI and analyzed for 24 compounds via 

liquid chromatography/tandem mass spectrometry (LC/MS/MS) compliant with Quality 

Systems Manual (QSM) Version 5.3 Table B-15 to fulfill the project DQOs:

• Twenty seven (27) soil samples from 11 boring locations;

• Nine (9) grab groundwater samples from 11 temporary well locations;

• Fifty-one (51) quality assurance (QA)/QC samples.

Figure 5-1 provides the sample locations for all media across the Facility. Table 5-1

presents the list of samples collected for each medium. Field documentation is provided 

in Appendix B. A log of Daily Notice of Field Activity was completed throughout the SI 

field activities, which is provided in Appendix B1. Sampling forms are provided in 

Appendix B2, land survey data are provided in Appendix B3, a Field Change Request 

form is provided in Appendix B4, and investigation-derived waste (IDW) polygons are
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 5-4

provided in Appendix B5. Additionally, a photographic log of field activities is provided 

in Appendix C.

5.1 PRE-INVESTIGATION ACTIVITIES

In preparation for the SI field activities, project team members participated in a Technical Project 

Planning (TPP) meeting, performed utility clearance, and sampled decontamination source 

water. Details of these activities are presented below. 

5.1.1 Technical Project Planning

The U.S. Army Corps of Engineers (USACE) TPP Process, Engineer Manual (EM) 200-1-2 

(DA, 2016a) defines four phases to project planning: (1) defining the project phase; (2) 

determining data needs; (3) developing data collection strategies; and (4) finalizing the data 

collection plan. The process encourages stakeholder involvement in the SI, beginning with 

defining overall project objectives, including DQOs, and formulating a sampling approach to 

address the AOIs identified in the PA. 

A combined TPP Meeting 1 and 2 was held on 7 October 2021, prior to SI field activities. The 

combined TPP Meeting 1 and 2 was conducted in general accordance with EM 200-1-2. The 

stakeholders for this SI included COARNG, ARNG, USACE, Colorado Department of Public 

Health and Environment (CDPHE), and representatives familiar with the Facility, the 

regulations, and the community. Stakeholders were provided the opportunity to make comments 

on the technical sampling approach and methods at the combined TPP Meeting 1 and 2. The 

outcome of the combined TPP Meeting 1 and 2 was memorialized in the UFP-QAPP Addendum 

(EA/Wood, 2022). 

A TPP Meeting 3 was held after the field event to discuss the results of the SI. Meeting minutes 

for TPP 3 are included in Appendix D of this report. Future TPP meetings will provide an 

opportunity to discuss results and findings, and future actions, where warranted.

5.1.2 Utility Clearance

WSP USA Environment & Infrastructure Inc. (WSP), previously doing business as Wood, 

contacted the Utility Notification Center of Colorado to notify them of intrusive work at the 

Facility. WSP contracted On Point Locating, a private utility location service, to perform utility 

clearance at the Facility. Utility clearance was performed at each of the proposed boring 

locations on 13 April 2022 with input from the WSP field team. Additional utility clearance was 

conducted on 23 June 2022 to accommodate sample step out locations and a concern with a 

potential obstruction at one sample location. WSP contracted Roaring Forks Utility Locators, 

LLC, a private utility location service, to perform the additional utility clearance at the Facility. 

General locating services and ground-penetrating radar (GPR) were used to complete the 

clearance. Additionally, the first 8 feet of each boring were pre-cleared by WSP’s drilling 

subcontractor, Traut Companies, using a hand auger to verify utility clearance in shallow 

subsurface where utilities would typically be encountered. The utilities were cleared to this depth 

based on utility information provided by Facility personnel. 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 5-5

5.1.3 Source Water and PFAS Sampling Equipment Acceptability

The potable water source used for decontamination of drilling equipment was confirmed to meet 

acceptability criteria, as defined in the UFP-QAPP Addendum, prior to the start of field 

activities. A sample from a potable water source at the outside spigot on the northeast corner of 

Building 1214, was collected on 7 October 2021, prior to mobilization, and analyzed for PFAS 

by LC/MS/MS compliant with QSM 5.3 Table B-15 (DoD, 2020). During field activities, the 

previously sampled source did not provide sufficient flow for the volume of water needed for 

drilling. The water source was then moved to a larger valve in the maintenance room on the 

building’s direct source of county water, which was tested on 9 June 2022. The results of the 

initial potable water sample and the second potable water sample (through the refill hose) used 

for drilling and decontamination of drilling equipment during the SI are provided in Appendix 

F. A discussion of the results is presented in the Data Usability Assessment (Appendix A).

Materials that were used within the sampling zone were confirmed as acceptable for use in the

PFAS sampling environment. The checklist of acceptable materials for use in the PFAS sampling 

environment was provided in the Standard Operating Procedures appendix to the Programmatic 

UFP-QAPP (EA, 2020).

5.2 HAND AUGER SOIL SAMPLING

During the first field event (13 April to 14 April 2022), a surface soil sample was collected from 

all eleven sample locations from 0 to 2 ft bgs using a hand auger. As AOI01-02 was located in a 

paved area, a sample of soil that had collected on the pavement near the AOI01-02 location, 

designated in this report as AOI01-2a, was taken to represent that location. The purpose of 

collecting surface soil samples prior to drilling activities was to use the results to determine how 

to manage IDW. All soil sample locations are shown on Figure 5-1. The hand auger locations

were selected based on the AOI information provided in the PA (AECOM, 2020) and as agreed 

upon by stakeholders during the TPP and review of the UFP-QAPP Addendum (EA/Wood,

2022). Non-dedicated sampling equipment (i.e., hand auger) was decontaminated between 

sampling locations. 

Each sample was collected into a laboratory-supplied PFAS-free high-density polyethylene 

(HDPE) bottle and labeled using a PFAS-free marker or pen. Samples were packaged on ice and 

transported via Federal Express (FedEx) under standard chain-of-custody (COC) procedures to 

the laboratory and analyzed for PFAS (LC/MS/MS compliant with QSM Version 5.3 Table B15) in accordance with the UFP-QAPP Addendum. QC samples and analysis were performed as 

described in the UFP-QAPP Addendum (EA/Wood, 2022). 

5.3 SOIL BORINGS AND SOIL SAMPLING

During the second field event (7 June to 14 July 2022), soil samples were collected via rotosonic

drilling methods in accordance with Standard Operating Procedure 025 Soil Sampling

(EA/Wood, 2022). A Layne track-mounted rig with 6-inch and 4-inch diameter core barrels were

used to collect continuous soil cores to the target depth at five of the eleven sample locations (see 

Section 5.9 for a description of exceptions). The soil boring locations are shown on Figure 5-1

and boring sample depths are provided in Table 5-1. Two boring locations were adjusted within 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 5-6

a 10-feet offset for reasons including drill rig access, utility avoidance and bias toward sampling 

within observed drainage features.

Up to three discrete soil samples were collected for chemical analysis from each soil boring: one 

sample at the surface (0 to 2 ft bgs) and two subsurface soil samples. Surface samples were 

collected by hand auger at all 11 boring locations during the first field event. As AOI01-02 was 

located in a paved area, the initial surface soil sample was from soil that had collected on the 

paved area near the location (designated in this report as AOI01-02a), therefore, a second surface 

soil sample was collected under the pavement at the actual sample location during the second 

mobilization. One subsurface soil sample was collected at a shallow depth between 14 to 15 ft 

bgs at all eleven boring locations. Due to subsurface conditions, collecting a deep soil sample 

was possible at only five of the boring locations. These samples were collected approximately 

one foot above the groundwater saturation observed at drilling. Groundwater was encountered at 

depths ranging from 73.70 to 94 ft bgs during drilling. Total boring completion depths, ranged 

from 80 to 120 ft bgs, to accommodate temporary well installation.

During the drilling, the soil cores were continuously logged for lithological descriptions by a 

field geologist using the Unified Soil Classification System at five of the eleven sample locations

(see Section 5.9 for a description of exceptions). A photoionization detector (PID) was used to 

screen the breathing zone during boring activities as a part of personal safety requirements.

Observations and measurements were recorded on electronic sampling forms (Appendix B2). 

Depth interval, recovery thickness, PID concentrations, moisture, relative density, Munsell color, 

and Unified Soil Classification System texture were recorded. The boring logs are provided in 

Appendix E. 

Each sample was collected into a laboratory-supplied PFAS-free high-density polyethylene 

(HDPE) bottle and labeled using a PFAS-free marker or pen. Samples were packaged on ice and 

transported via FedEx under standard COC procedures to the laboratory and analyzed for PFAS 

(LC/MS/MS compliant with QSM Version 5.3 Table B-15), total organic carbon (TOC) (EPA 

Method 9060A), pH (EPA Method 9045D), and grain size (ASTM Method D-422) in accordance 

with the UFP-QAPP Addendum (EA/Wood, 2022). 

Field duplicate samples were collected at a rate of 10% and analyzed for the same parameters as 

the accompanying samples. Matrix spike/matrix spike duplicate (MS/MSDs) were collected at a 

rate of 5% and analyzed for the same parameters as the accompanying samples. In instances 

when non-dedicated sampling equipment was used, such as a hand auger for the surface soil 

samples, one equipment blank (EB) was collected per day and analyzed for the same parameters 

as the soil samples. A temperature blank was placed in each cooler for use in confirming that

samples were preserved at or below 6 degrees Celsius (°C) during shipment. 

The sonic drilled borings were converted to temporary wells, which were subsequently 

abandoned after sampling and surveying in accordance with the UFP-QAPP Addendum 

(EA/Wood, 2022). After removal of the casings to a depth of at least 5 ft bgs, boreholes were 

abandoned using bentonite chips. Most boring were installed in grass or gravel areas to avoid 

disturbing concrete or asphalt surfaces. One location, AOI01-02, was drilled through the asphalt

of a storage area off the flight apron/taxiway and surface completed with dyed asphalt cold 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 5-7

patch. A Facility member approved surface completions at all boring locations before the field 

crew demobilized. 

5.4 TEMPORARY WELL INSTALLATION AND GROUNDWATER GRAB 

SAMPLING

Temporary wells were installed using a Layne track mounted sonic drilling rig with 6-inch and 

4-inch core barrels. Once the borehole was advanced to the desired depth, a temporary well was 

constructed of a 10 ft section of 1- or 2-inch Schedule 40 poly-vinyl chloride (PVC) screen with 

sufficient casing to reach the ground surface. New PVC pipe and screen were used at each 

location to avoid cross contamination between locations. The screen intervals for the temporary 

wells are provided in Table 5-2.

Groundwater samples were collected from nine of the eleven temporary wells. Following 

installation of two wells (AOI01-01 and AOI01-05), the water level dropped below the screen,

and it was not possible to collect groundwater samples. Water samples were collected after a 

period of time following well installation to allow drilling water to dissipate and groundwater to 

infiltrate and recharge the temporary well screen intervals, using a PFAS-free portable bladder

pump with PFAS-free polyethylene bladders and dedicated HDPE tubing. The temporary wells 

were purged at a rate determined in the field to reduce turbidity and draw down prior to 

sampling. Water quality parameters (e.g., temperature, specific conductance, pH, dissolved 

oxygen, oxidation-reduction potential, and turbidity) were measured using a water quality meter 

and turbidimeter and recorded on the field sampling form (Appendix B2) before each grab 

sample was collected in a separate container. Due to a damaged well casing, the groundwater 

sample from one location (HAATS-02) was collected using a 0.46” clear PVC Geotech 

Disposable Geobailer. A subsample of each groundwater sample was collected in a separate 

container, and a shaker test was completed to identify if there were any foaming. No foaming 

was noted in any of the groundwater samples.

Each sample was collected in laboratory-supplied PFAS-free HDPE bottles and labeled using a 

PFAS-free marker or pen. Samples were packaged on ice and transported via FedEx under 

standard COC procedures to the laboratory and analyzed for PFAS by LC/MS/MS compliant 

with QSM Version 5.3 Table B-15 in accordance with the UFP-QAPP Addendum (EA/Wood

2022). 

Field duplicate samples were collected at a rate of 10% and analyzed for the same parameters as 

the accompanying samples. MS/MSDs were collected at a rate of 5% and analyzed for the same 

parameters as the accompanying samples. When sampling, one FB was collected a day in 

accordance with the UFP-QAPP Addendum (EA/Wood, 2022). In instances when non-dedicated 

sampling equipment was used, such as a bladder pump, one EB was collected a day and analyzed 

for the same parameters as the groundwater samples. A temperature blank was placed in each 

cooler for use in confirming that samples were preserved at or below 6°C during shipment. 

Following well surveying (described below in Section 5.6), temporary wells were abandoned in 

accordance with the SI UFP-QAPP Addendum (EA/Wood, 2022) by removing the PVC and 

backfilling the hole with bentonite chips. 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 5-8

5.5 SYNOPTIC WATER LEVEL MEASUREMENTS

A synoptic groundwater gauging event was performed on 14 July 2022. Groundwater elevation 

measurements were collected from nine of the eleven new temporary monitoring wells. Water 

level measurements were taken from the survey mark on the northern side of the well casing.

Groundwater elevation data is provided in Table 5-3. A groundwater flow contour map is 

provided as Figure 2-5.

5.6 SURVEYING

The northern side of each new temporary well casing and ground surface at the top of each 

boring were surveyed using a Trimble R10 real-time kinematic differential global positioning 

system. Positions were collected in the applicable Universal Transverse Mercator zone projection 

for the Colorado Central 0502 State Plane Grid North American Datum 1983. Surveying data 

were collected on 14 July 2022 and are provided in Appendix B3. 

5.7 INVESTIGATION-DERIVED WASTE

As of the date of this report, the disposal of PFAS IDW is not regulated federally. IDW 

generated during the SI is considered non-hazardous waste and was managed in accordance with 

the UFP-QAPP Addendum (EA/Wood 2022). 

For select locations where surface soil samples did not exceed SLs and the location condition

allowed, soil cuttings were thin spread using a bucket loader or placed to not disturb the 

landscaping, depending on the volume returned. For locations where surface soil did exceed the 

SL, soil IDW (i.e., soil cuttings) generated during the SI activities were contained in labeled 55-

gallon DOT approved steel drums and left onsite in an area designated by Facility personnel. The 

soil IDW was not sampled and assumes the characteristics of the associated soil samples

collected from that source location. Liquid IDW generated during SI activities (i.e., purge water 

and decontamination fluids) were containerized in labeled, 275-gallon caged HPDE intermediate 

bulk containers and left onsite in an area designated by Facility personnel. The liquid IDW was 

not sampled and assumes the characteristics of the associated groundwater samples collected 

from that source location. For select locations where surface soil samples did not exceed SL and 

the location condition allowed, return drilling water was purged away from the boring into 

Facility drainage features. All return water was containerized upon reaching the groundwater 

bearing zone. 

Geographic coordinates were collected around each location where IDW was placed (i.e., an 

IDW polygon or point). The IDW polygons are displayed on the figure in Appendix B5.

The IDW disposal is being managed separately under a contract with EA Engineering, Science, 

and Technology, Inc. Specifics on the disposal of solid and liquid IDW will be addressed in an 

IDW Treatment Memorandum.

Other solids such as spent personal protective equipment, plastic sheeting, tubing, rope, unused 

monitoring well construction materials, and other environmental media generated during the 

field activities were disposed of at a licensed solid waste landfill.
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 5-9

5.8 LABORATORY ANALYTICAL METHODS

Samples were analyzed by LC/MS/MS, compliant with QSM Version 5.3 Table B-15, at 

Eurofins in Lancaster, Pennsylvania, a DoD ELAP and NELAP-certified laboratory.

Soil samples were also analyzed for TOC using EPA Method 9060A, pH by EPA Method 

9045D, and grain size using ASTM Method D-422.

5.9 Deviations from SI UFP-QAPP Addendum

Deviations from the UFP-QAPP Addendum occurred based on conditions encountered during 

field activities. These deviations were discussed between EA, WSP, ARNG, and USACE. Three 

deviations from the UFP-QAPP Addendum are noted below: 

Due to subsurface conditions, drilling deeper than 20-40 ft bgs with an open ended drill bit 

proved extremely difficult for the equipment and tooling. In order to complete the borings and

install temporary wells at AOI01-02, AOI01-04, AOI02-01, AOI02-02, and AOI03-01, a flat 

face drill bit was used deeper than approximately 15 ft bgs. As there is no core return when using 

the flat face drill bit, continuous cores were not collected. No deep subsurface samples were 

collected at these locations and only surface soil and shallow subsurface samples were collected.

This change is noted in the Field Change Request Form provided in Appendix B4.

At HAATS-02, the PVC well casing was damaged (likely during installation) causing a 

constriction approximately 20 ft bgs. When field personnel attempted to collect a groundwater 

sample, the bladder pump could not be lowered past the constriction. A second attempt was 

made with a smaller bladder pump; however, it also could not be lowered past the well 

constriction. In order to get a sample from the temporary well, a 0.46” clear PVC Geotech 

Disposable Geobailer was used to collect the groundwater sample. 

Due to the water used for drilling, it was difficult to accurately determine the groundwater level 

at the time of drilling. At sample locations AOI01-01 and AOI01-05, the wells were set based on 

observations made during drilling and groundwater depths observed at adjacent locations. After 

setting the wells and allowing them to sit overnight, it was determined that the groundwater level 

was below the bottom of the screen, and the wells were dry. The groundwater level was checked 

daily at both locations, however both wells remained dry for the duration of the event. Based on 

conversations with the ARNG, it was determined that it was not necessary to redrill these two

wells because the surface soil results were above the SLs and this AOI would be going to RI

based on the surface soil exceedances. 

During purging of wells HAATS-03, HAATS-01, AOI01-03, AOI02-01, AOI02-02, and AOI03-

01, not all water quality parameters stabilized prior to taking a groundwater sample. As the 

turbidity did not drop below 25 Nephelometric Turbidity Units, groundwater samples were 

collected after three 20 minute purge cycles had been completed (as indicated in the UFPQAPP). 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 5-10

Table 5-1. Site Inspection Samples by Medium

Sample Identification

Sample 

Collection 

Date

Sample Depth

(ft bgs)

PFAS(LC/MS/MS compliant with QSM 5.3 Table B-15)TOC(EPA Method 9060A)pH (EPA Method 9045D)Grain Size (ASTM D422)

Comments

Soil Samples

AOI01-01-SB-0-2 4/14/2022 0-2 x

Parent Sample of 

DUP-01-SB-0-2

DUP-01-SB-0-2 4/14/2022 0-2 x Field Duplicate

AOI01-01-SB-14-15 6/17/2022 14-15 x

AOI01-01-SB-74-75 6/17/2022 74-75 x

AOI01-02-SB-0-2 4/14/2022 0-2 x

Collected from 

AOI01-02a (surface 

soil sample 

collected from on 

top of pavement 

near the AOI01-02 

location)

AOI01-02-SB-0-2 6/28/2022 0-2 x

Surface soil sample 

collected from 

actual AOI01-02 

location

AOI01-02-SB-1-3 6/28/2022 1-3 x

AOI01-02-SB-14-15 6/28/2022 14-15 x

AOI01-03-SB-0-2 4/14/2022 0-2 x

Parent Sample of 

DUP-02-SB-0-2

DUP-02-SB-0-2 4/14/2022 0-2 x Field Duplicate

AOI01-03-SB-14-15 6/23/2022 14-15 x

AOI01-03-SB-74-75 6/23/2022 74-75 x

AOI01-04-SB-0-2 4/14/2022 0-2 x

AOI01-04-SB-14-15 7/12/2022 14-15 x x x x

AOI01-05-SB-0-2 4/14/2022 0-2 x

AOI01-05-SB-0-2-MS 4/14/2022 0-2 x

AOI01-05-SB-0-2-MSD 4/14/2022 0-2 x

AOI01-05-SB-14-15 6/22/2022 14-15 x x x x

Parent Sample of 

DUP-01-TOC-pHgrain size

DUP-01-TOC-pH-grain size 6/22/2022 14-15 x x x x Field Duplicate

AOI01-05-SB-84-85 6/22/2022 84-85 x

AOI02-01-SB-0-2 4/14/2022 0-2 x

AOI02-01-SB-14-15 6/24/2022 14-15 x x x x

Parent Sample of 

HAATS-DUP-02-

SB

AOI02-01-SB-14-15-MS 6/24/2022 14-15 x

AOI02-01-SB-14-15-MSD 6/24/2022 14-15 x

HAATS-DUP-02-SB 6/24/2022 14-15 x Field Duplicate

AOI02-02-SB-0-2 4/14/2022 0-2 x
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 5-11

Sample Identification

Sample 

Collection 

Date

Sample Depth

(ft bgs)

PFAS(LC/MS/MS compliant with QSM 5.3 Table B-15)TOC(EPA Method 9060A)pH (EPA Method 9045D)Grain Size (ASTM D422)

Comments

AOI02-02-SB-14-15 7/1/2022 14-15 x

Parent Sample of 

HAATS-DUP-03-

SB

HAATS-DUP-03-SB 7/1/2022 14-15 x Field Duplicate

AOI03-01-SB-0-2 4/14/2022 0-2 x

AOI03-01-SB-14-15 7/13/2022 14-15 x x x x

AOI03-01-SB-14-15-MS 7/13/2022 14-15 x

AOI03-01-SB-14-15-MSD 7/13/2022 14-15 x

HAATS-01-SB-0-2 4/13/2022 0-2 x

HAATS-01-SB-14-15 6/15/2022 14-15 x

HAATS-01-SB-78-79 6/16/2022 78-79 x

HAATS-02-SB-0-2 4/14/2022 0-2 x

HAATS-02-SB-14-15 6/21/2022 14-15 x

Parent Sample of 

HAATS-DUP-01-

SB

HAATS-DUP-01-SB 6/21/2022 14-15 x Field Duplicate

HAATS-02-SB-87-88 6/21/2022 87-88 x

HAATS-03-SB-0-2 4/14/2022 0-2 x

Groundwater Samples

AOI01-02-GW 7/12/2022 110 x

AOI01-02-GW-MS 7/12/2022 110 x

AOI01-02-GW-MSD 7/12/2022 110 x

AOI01-03-GW 6/27/2022 115 x

Parent Sample of 

HAATS-DUP-01-

GW

HAATS-DUP-01-GW 6/27/2022 115 x Field Duplicate

AOI01-04-GW 7/13/2022 110 x

AOI02-01-GW 6/29/2022 115 x

Parent Sample of 

HAATS-DUP-02-

GW

HAATS-DUP-02-GW 6/29/2022 115 x Field Duplicate

AOI02-02-GW 6/29/2022 110 x

AOI03-01-GW 7/14/2022 110 x

HAATS-01-GW 6/17/2022 80 x

HAATS-02-GW 7/12/2022 73 x

HAATS-03-GW 6/16/2022 97 x

Blank Samples

EB-04-13 4/13/2022 -- x

Equipment Blank 

Collected from 

Hand Auger

EB-04-14 4/14/2022 -- x

Equipment Blank 

Collected from 

Hand Auger

EB-DECONHOSE-1-JUN-9 6/9/2022 -- x

Equipment Blank 

Collected from 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 5-12

Sample Identification

Sample 

Collection 

Date

Sample Depth

(ft bgs)

PFAS(LC/MS/MS compliant with QSM 5.3 Table B-15)TOC(EPA Method 9060A)pH (EPA Method 9045D)Grain Size (ASTM D422)

Comments

Decon Water 

Supply Hose 

EB-DECONHOSE-2-JUN-9 6/9/2022 -- x

Equipment Blank 

Collected from 

Decon Water 

Supply Hose

EB-HOSE-2IN-JUN-9 6/9/2022 -- x

Second Potable 

Water Sample

EB-JUN-15 6/15/2022 -- x

Equipment Blank 

from Stainless Steel 

Screen (not used)

EB-JUN-16 6/16/2022 -- x

Equipment Blank 

Collected from 

Water Storage Tank

EB-JUN-17 6/17/2022 -- x

Equipment Blank 

Collected from 

Water Level Meter

EB-JUN-21 6/21/2022 -- x

Equipment Blank 

Collected from 

Hand Auger

EB-JUN-22 6/22/2022 -- x

Equipment Blank 

Collected from 

Hand Auger

EB-JUN-27 6/27/2022 -- x

Equipment Blank 

Collected from 

Bladder Pump

EB-JUN-28 6/28/2022 -- x

Equipment Blank 

Collected from 

Hand Auger

EB-JUN-29 6/29/2022 -- x

Equipment Blank 

Collected from 

Water Level Meter

EB-JUN-30 6/30/2022 -- x

Equipment Blank 

Collected from 

Drill Rod

EB-1-JUL-12 7/12/2022 -- x

Equipment Blank 

Collected from 

Bailer

EB-2-JUL-12 7/12/2022 -- x

Equipment Blank 

Collected from 

Drill Rod

EB-1-JUL-13 7/13/2022 -- x

Equipment Blank 

Collected from 

Bladder Pump

EB-2-JUL-13 7/13/2022 -- x

Equipment Blank 

Collected from 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 5-13

Sample Identification

Sample 

Collection 

Date

Sample Depth

(ft bgs)

PFAS(LC/MS/MS compliant with QSM 5.3 Table B-15)TOC(EPA Method 9060A)pH (EPA Method 9045D)Grain Size (ASTM D422)

Comments

Drill Rod

EB-JUL-14 7/14/2022 -- x

Equipment Blank 

Collected from 

Water Level Meter

FB-04-13 4/13/2022 -- x Field Blank

FB-04-14 4/14/2022 -- x Field Blank

FB-JUN-15 6/15/2022 -- x Field Blank

FB-JUN-16 6/16/2022 -- x Field Blank

FB-JUN-17 6/17/2022 -- x Field Blank

FB-JUN-21 6/21/2022 -- x Field Blank

FB-JUN-22 6/22/2022 -- x Field Blank

FB-JUN-23 6/23/2022 -- x Field Blank

FB-JUN-24 6/24/2022 -- x Field Blank

FB-JUN-27 6/27/2022 -- x Field Blank

FB-JUN-28 6/28/2022 -- x Field Blank

FB-JUN-29 6/29/2022 -- x Field Blank

FB-JUN-30 6/30/2022 -- x Field Blank

FB-JUL-1 7/1/2022 -- x Field Blank

FB-JUL-11 7/11/2022 -- x Field Blank

FB-JUL-12 7/12/2022 -- x Field Blank

FB-JUL-13 7/13/2022 -- x Field Blank

FB-JUL-14 7/14/2022 -- x Field Blank

Notes:

ASTM = American Society for Testing and Materials

EB = equipment blank

FB = field blank

DUP = field duplicate

ft bgs = feet below ground surface

MS/MSD = matrix spike/ matrix spike duplicate

PFAS = per- and polyfluoroalkyl substances

TOC = total organic carbon

EPA = Environmental Protection Agency
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 5-14

Table 5-2. Soil Boring Depths and Temporary Well Screen Intervals

Area of Interest Boring Location

Soil Boring Depth

(ft bgs)

Temporary Well 

Screen Interval

(ft bgs)

Boundary

HAATS-01 90 80 - 90

HAATS-02 93 83 - 93

HAATS-03 107 97 - 107

1

AOI01-01 80 70 - 80

AOI01-02 115 105 - 115

AOI01-03 120 110 - 120

AOI01-04 115 105 - 115

AOI01-05 90 80 - 90

2 AOI02-01 120 110 - 120

AOI02-02 115 105 - 115

3 AOI03-01 115 105 - 115

Notes:

ft bgs = feet below ground surface
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 5-15

Table 5-3. Groundwater Elevation

Monitoring Well 

ID

Top of Casing Elevation

(ft NAVD88)

Depth to Water

(ft btoc)

Groundwater Elevation

(ft NAVD 88)

HAATS-01 6451.792 75.68 6376.11

HAATS-02 6447.446 74.19 6373.26

HAATS-03 6458.712 80.02 6378.69

AOI01-01 6458.321 DRY NA

AOI01-02 6454.755 83.72 6371.04

AOI01-03 6449.029 78.60 6370.43

AOI01-04 6451.414 80.07 6371.34

AOI01-05 6445.444 DRY NA

AOI02-01 6447.838 91.80 6356.04

AOI02-02 6445.829 94.20 6351.63

AOI03-01 6442.815 94.77 6348.05

Notes: 

btoc = below top of casing

ft = feet

NA = not applicable, wells were dry

NAVD88 = North American Vertical Datum 1988
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 5-16

This page intentionally left blank
#*

#*

#*

#*

#*

#*

#*

#*

#*

#*

#*

AOI 2

HAZMAT Storage

Building 1214

AOI 3

Flight Ramp FTA

Flight Ramp

HAATS-03

AOI01-02

AOI01-01

AOI02-02

AOI02-01

AOI03-01

AOI01-05

AOI01-04

AOI01-03

HAATS-02

HAATS-01

0 200

Feet

3

P:\Project\AMEC Inter-Office Projects\3031200026 HAATS\3031200026 HAATS\5-1_SiteInspectionSampleLocations.mxd

Facility Data #* Site Inspection Sample Location

Surface Water Flow Direction

Facility Boundary

Area of Interest

Army National Guard Site Inspections

High Altitude Aviation Training Site

Gypsum, Colorado

Figure 5-1

Site Inspection Sample Locations

Date:......................JANUARY 2023

Prepared By:............................WSP

Prepared For:.......................USACE

Projection:.........NAD 83 StatePlane

Data Sources: 

ESRI 2020

AECOM 2020

^_ CO
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 5-18

This page intentionally left blank
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 6-1

6. SITE INSPECTION RESULTS

This section presents the analytical results of the SI. The SLs used in this evaluation are 

presented in Section 6.1 and Table 6-1. A discussion of the results for each AOI is provided in 

Sections 6.3 through 6.5. Tables 6-2 through 6-5 present results in soil or groundwater for the 

relevant compounds. Tables that contain all results are provided in Appendix F, and the 

laboratory reports are provided in Appendix G. 

6.1 SCREENING LEVELS

The DoD has adopted a policy to retain facilities in the CERCLA process based on risk-based 

SLs for soil and groundwater, as described in a memorandum from the OSD dated 6 July 2022 

(Assistant Secretary of Defense, 2022). The ARNG program under which this SI was performed 

follows this DoD policy. Should the maximum concentration for sampled media exceed the SLs 

established in the July 2022 OSD memorandum, the AOI will proceed to the next phase under 

CERCLA. The SLs established in the July 2022 OSD memorandum apply to the five compounds 

presented on Table 6-1.

Table 6-1. Screening Levels (Soil and Groundwater)

Analyte2

Residential

(Soil)

(μg/kg)1

0-2 ft bgs

Industrial / Commercial

Composite Worker

(Soil)

(μg /kg) 1

2-15 ft bgs

Tap Water

(Groundwater)

(ng/L) 1

PFOA 19 250 6

PFOS 13 160 4

PFBS 1,900 25,000 601

PFHxS 13 1,600 39

PFNA 19 250 6

Notes:

1. Assistant Secretary of Defense. July 2022. Risk Based Screening Levels in Groundwater and Soil using 

U.S. Environmental Protection Agency’s (EPA’s) Regional Screening Level Calculator. Hazard Quotient 

(HQ)=0.1. May 2022. 

2. Of the six PFAS compounds presented in the 6 July 2022 OSD memorandum, HFPO-DA (commonly 

referred to as GenX) was not included as an analyte at the time of this SI. Based on the CSM developed 

during the PA and revised based on SI findings, the presence of HFPO-DA is not anticipated at the facility 

because HFPO-DA is generally not a component of MIL-SPEC AFFF and based on its history including 

distribution limitations that restricted use of GenX, it is generally not a component of other products the 

military used. In addition, it is unlikely that GenX would be an individual chemical of concern in the 

absence of other PFAS.

Abbreviations:

μg/kg = microgram(s) per kilogram

bgs = below ground surface

ft = feet

ng/L = nanogram(s) per liter
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 6-2

The data in the subsequent sections are compared against the SLs presented in Table 6-1. The 

SLs for groundwater are based on direct ingestion. The SLs for soil are based on incidental 

ingestion and are applied to the depth intervals reasonably anticipated to be encountered by the 

receptors identified at the Facility: the residential scenario is applied to surface soil results (0 to 2 

feet bgs) and the industrial/commercial worker scenario is applied to shallow subsurface soil 

results (2 to 15 feet bgs). The SLs are not applied to deep subsurface soil results (>15 feet bgs) 

because 15 feet is the anticipated limit of construction activities.

6.2 SOIL PHYSICOCHEMICAL ANALYSES

To provide basic soil parameter information, soil samples were analyzed for TOC, pH, and grain 

size, which are important for evaluating transport through the soil medium. Appendix G

contains the results of the TOC, pH, and grain size sampling. 

The data collected in this investigation will be used in subsequent investigations, where 

appropriate, to assess fate and transport. According to the Interstate Technology Regulatory 

Council (ITRC), several important PFAS partitioning mechanisms include hydrophobic and 

lipophobic effects, electrostatic interactions, and interfacial behaviors. At relevant environmental 

pH values, certain PFAS are present as organic anions, and are therefore relatively mobile in 

groundwater (Xiao et al., 2015), but tend to associate with the organic carbon fraction that may 

be present in soil or sediment (Higgins and Luthy 2006; Guelfo and Higgins 2013). When 

sufficient organic carbon is present, organic carbon normalized distribution coefficients (Koc 

values) can help in evaluating transport potential, though other geochemical factors (for example, 

pH and presence of polyvalent cations) may also affect PFAS sorption to solid phases (ITRC, 

2018). 

6.3 AOI 1

This section presents the analytical results for soil and groundwater in comparison to SLs for 

AOI 1: Parking Apron/Taxiway. The soil and groundwater results are summarized in Table 6-2

through Table 6-5. Soil and groundwater results are presented on Figures 6-1 through Figure 6-

7.

6.3.1 AOI 1 Soil Analytical Results

Soil samples were collected from five boring locations associated with AOI 1 during the SI. 

Figure 6-1 through Figure 6-5 present the ranges of detections in soil. Tables 6-2 through Table 

6-4 summarize the soil results.

Surface soil (0 to 2 ft bgs) was sampled from five AOI 1 boring locations (AOI01-01 through 

AOI01-05) and three locations that were upgradient of AOI 1 (HAATS-01, HAATS-02, and 

HAATS-03). Soil was sampled from shallow subsurface soil intervals (14 to 15 ft bgs) from 

boring locations AOI01-01 through AOI01-05, HAATS-01, and HAATS-02. Soil was also 

sampled from deep subsurface soil intervals (74 to 88 ft bgs) from boring locations AOI01-01,

AOI01-03, AOI01-05, HAATS-01, and HAATS-02. 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 6-3

PFOS was detected in surface soil from AOI 1 at concentrations exceeding the SL. PFHxS, 

PFNA, and PFOA were detected in surface soil below their respective SLs at AOI 1 sample 

locations. PFOS was detected at four of the five AOI 1 sample locations at concentrations that 

ranged from 5.2 J micrograms per kilogram (μg/kg) to 38 μg/kg and exceeded the SL at three of 

the locations (AOI01-01 and its duplicate, AOI01-03 [but not its duplicate], and AOI01-05). 

PFOS was detected in the initial surface soil sample collected near AOI01-02 (designated as 

AOI01-02a and taken during the first field event) but was not detected in the surface soil sample

taken from beneath the asphalt at the AOI01-02 location. PFOA was detected at three of the five 

AOI 1 locations with concentrations ranging from 0.24 J μg/kg to 0.42 J μg/kg. PFOA was 

detected at the surface soil sample taken from AOI01-02a, but was not detected in the surface 

soil sample taken from AOI01-02. PFHxS was detected at four of the five AOI 1 locations with 

concentrations ranging from 0.52 J μg/kg to 0.99 μg/kg. PFHxS was detected in both the surface 

soil sample collected at AOI01-02a and at AOI01-02. PFNA was only detected in the surface soil 

sample collected from AOI01-02a. PFBS was not detected in the surface soil samples.

PFOS, PFOA, and PFHxS were detected in the surface soil samples taken from the upgradient

locations (HAATS-01, HAATS-02, and HAATS-03) below their respective SLs. PFOS was 

detected at all three locations at concentrations ranging from 0.53 J μg/kg to 9.4 μg/kg. PFOA 

was detected at two of the three locations at 0.21 J μg/kg and 0.31 J μg/kg. PFHxS was detected 

at all three locations at concentrations ranging from 0.29 J μg/kg to 0.56 J μg/kg. PFBS and 

PFNA were not detected in the surface soil samples from the three upgradient locations. 

PFOA, PFOS, PFHxS, PFNA, and PFBS were not detected in the shallow or deep subsurface 

soil samples at the AOI 1 (AOI01-01, AOI01-03, and AOI01-05) or the upgradient sample 

locations (HAATS-01 and HAATS-02). 

6.3.2 AOI 1 Groundwater Analytical Results 

Groundwater samples were collected from three temporary monitoring wells associated with

AOI 1 during the SI (AOI01-02, AOI01-03, and AOI01-04). Additionally, groundwater samples 

were collected from the three temporary monitoring wells located upgradient of AOI 1 (HAATS01, HAATS-02, and HAATS-03). Figures 6-6 and 6-7 presents the ranges of detections in 

groundwater. Table 6-5 summarizes the groundwater results.

PFOA was detected at a concentration exceeding its SL at one AOI 1 temporary monitoring well. 

PFBS and PFHxS were detected at AOI 1 groundwater sample locations below their respective 

SLs. PFOA was detected at one of the three sampled AOI 1 temporary monitoring wells at a 

concentration of 8.0 ng/L (AOI01-02), which exceeded the SL. PFBS was detected at two of the 

three sampled AOI 1 temporary monitoring wells at 0.63 J ng/L (in the duplicate sample taken at 

AOI01-03, but not the primary sample) and 15 ng/L. PFHxS was detected at one of the sampled 

AOI 1 temporary monitoring wells at a concentration of 6.3 ng/L. PFNA and PFOS were not 

detected at the three sampled AOI 1 temporary monitoring wells. 

PFOS and PFOA were detected at concentrations exceeding their respective SLs at the 

temporary monitoring wells located upgradient of AOI 1. PFBS, PFHxS, and PFNA were 

detected below their SLs at the groundwater sample locations upgradient of AOI 1. PFOA was 

detected at all three upgradient temporary monitoring wells at concentrations ranging from 2.2 J+ 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 6-4

ng/L to 21 ng/L and exceeded its SL at two locations (HAATS-01 and HAATS-03). PFOS was 

detected at two of the three upgradient temporary monitoring wells at 2.3 J+ ng/L and 5.4 ng/L 

and exceeded its SL at one location (HAATS-02). PFBS was detected at all three upgradient 

temporary monitoring wells at concentrations ranging from 0.45 J ng/L to 13 J+ ng/L. PFHxS 

was detected at all three upgradient temporary monitoring wells at concentrations ranging from 

2.9 ng/L to 23 J+ ng/L. PFNA was detected at one of the three upgradient temporary monitoring 

wells at 1.2 J ng/L.

6.3.3 Conclusions

Based on the results of the SI, PFOS was detected in soil above its SL at three of the five AOI 1 

sample locations. PFOA was detected in groundwater exceeding its SL at one AOI 1 sample 

location. Based on the exceedances of the SLs in soil and groundwater, further evaluation at AOI 

1 is warranted. Concentrations of PFOA and PFOS were detected in groundwater above their 

respective SLs at upgradient temporary monitoring well locations. These results may indicate a 

potential off-facility source upgradient of AOI 1. 

6.4 AOI 2

This section presents the analytical results for soil and groundwater in comparison to SLs for 

AOI 2: HAZMAT Storage Area. The soil and groundwater results are summarized in Table 6-2

through Table 6-5. Soil and groundwater results are presented on Figures 6-1 through Figure 6-

7.

6.4.1 AOI 2 Soil Analytical Results

Soil samples were collected from two boring locations associated with AOI 2 during the SI. 

Figure 6-1 through Figure 6-5 present the ranges of detections in soil. Tables 6-2 through Table 

6-4 summarize the soil results.

Surface soil (0 to 2 ft bgs) was sampled from boring locations AOI02-01 and AOI02-02. Soil 

was also sampled from shallow subsurface soil (14 to 15 ft bgs) from boring locations AOI02-01 

and AOI02-02. No deep subsurface soil samples were collected at AOI 2. 

PFOS was detected in surface soil at concentrations exceeding the SL. PFOA and PFHxS were 

detected in surface soil at concentrations below their respective SLs. PFOS was detected at both 

sample locations at 0.98 μg/kg and 22 μg/kg and exceeded the SL at one location (AOI02-01). 

PFOA was detected at one of the sample locations with a concentration of 0.34 J μg/kg. PFHxS 

was detected at both locations at 0.41 J μg/kg and 0.62 J μg/kg. PFBS and PFNA were not 

detected in the surface soil samples. 

PFOS and PFHxS were detected in shallow subsurface soil at concentrations below their 

respective SLs. PFOS was detected at one of the two sample locations at 60 J- μg/kg (48 μg/kg

in its duplicate). PFHxS was detected at one of the two sample locations at 2.6 μg/kg (2.5 μg/kg

in its duplicate). PFOA, PFBS and PFNA were not detected in the shallow subsurface soil 

samples. 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 6-5

Deep subsurface soil samples were not collected at AOI 2. 

6.4.2 AOI 2 Groundwater Analytical Results

Groundwater samples were collected from two temporary wells associated with AOI 2 during the 

SI. Figures 6-6 and 6-7 presents the ranges of detections in groundwater. Table 6-5 summarizes 

the groundwater results.

Groundwater was sampled from temporary monitoring well locations AOI02-01 and AOI02-02. 

PFOA and PFHxS were detected at concentrations exceeding their respective SLs. PFBS and 

PFOS were detected at concentrations below their respective SLs. PFOA was detected at one of 

the two temporary monitoring wells at a concentration of 6.1 ng/L which exceeded the SL.

PFHxS was detected at both sample locations at 1.4 J+ ng/L (1.1 J ng/L in the duplicate) and 63 

ng/L and exceeded the SL at one location (A0I02-02). PFOS was detected at one location at a 

concentration of 1.8 J+ ng/L. PFBS was detected at one location at a concentration of 27 ng/L. 

PFNA was not detected in AOI 2 groundwater samples.

6.4.3 Conclusions

Based on the results of the SI, PFOS was detected in soil above its SL. PFOA and PFHxS were

detected in groundwater at concentrations above their respective SLs. Based on the exceedances 

of the SLs in soil and groundwater, further evaluation at AOI 2 is warranted. 

6.5 AOI 3

This section presents the analytical results for soil and groundwater in comparison to SLs for 

AOI 3: Building 1214. The soil and groundwater results are summarized in Table 6-2 through 

Table 6-5. Soil and groundwater results are presented on Figures 6-1 through Figure 6-7.

6.5.1 AOI 3 Soil Analytical Results

Soil samples were collected from one boring location associated with AOI 3 during the SI. 

Figure 6-1 through Figure 6-5 present the ranges of detections in soil. Tables 6-2 and Table 6-4

summarize the soil results.

Surface soil (0 to 2 ft bgs) was sampled from boring location AOI03-01. Soil was also sampled 

from shallow subsurface soil (14 to 15 ft bgs) from boring location AOI03-01. No deep 

subsurface soil samples were collected at AOI 3.

PFOS and PFHxS were detected in surface soil at concentrations below their respective SLs. 

PFOS was detected with a concentration of 2.8 J μg/kg. PFHxS was detected at a concentration 

of 0.51 J μg/kg. PFOA, PFNA, and PFBS were not detected in the surface soil samples. 

PFOA, PFOS, PFHxS, PFNA, and PFBS were not detected in the shallow subsurface soil 

sample.
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 6-6

6.5.2 AOI 3 Groundwater Analytical Results

Groundwater samples were collected from one temporary well associated with AOI 3 during the 

SI. Figures 6-6 and 6-7 presents the ranges of detections in groundwater. Table 6-5 summarizes 

the groundwater results.

Groundwater was sampled from temporary monitoring well location AOI03-01.

PFHxS and PFBS were detected at concentrations below their respective SLs. PFHxS was 

detected at a concentration of 4.4 ng/L. PFBS was detected at a concentration of 1.9 ng/L.

PFOA, PFOS, and PFNA were not detected in the AOI 3 groundwater sample.

6.5.3 Conclusions

Based on the results of the SI, PFOS and PFHxS were detected in soil below their respective

SLs. PFHxS and PFBS were detected in groundwater at concentrations below their respective

SLs. There were no exceedances of the SLs in soil or groundwater, and no further evaluation at 

AOI 3 is warranted.
Table 6-2

PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Surface Soil

Site Inspection Report

HAATS

Analyte OSD Screening Level 1 Result Qual Result Qual Result Qual Result Qual 

PFBS 1900 ND U ND U ND U ND U PFHxS 130 0.62 J 0.62 J 0.98 0.86 PFNA 19 ND U ND U 0.23 J ND U PFOA 19 ND U ND U 0.33 J ND U PFOS 13 38 23 13 ND U 

Notes Gray Fill Detected concentration exceeded OSD Screening Levels *Surface soil sample collected on 4/14/2022 consisted of sediment collecting on asphalt. 

A second surface soil sample was collected below the asphalt on 6/28/2022. 

References 

1. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculated

for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA’s

Regional Screening Level Calculator. HQ=0.1. May 2022. The screening levels for soil are

based on residential scenario for incidental ingestion of contaminated soil.

Interpreted Qualifiers

J = Estimated concentration.U = The analyte was not detected at a level greater than or equal to the adjusted DL.Acronyms and Abbreviationsμg/kg microgram(s) per kilogramAOI Area of InterestDUP duplicateHAATS High Altitude Army Training SiteHQ Hazard QuotientID identificationLCMSMS liquid chromatography with tandem mass spectrometryLOD limit of detectionLOQ limit of quantitationND analyte not detected above the LOD (LOD values are presented in Appendix F)OSD Office of the Secretary of the DefenseQSM Quality Systems ManualPFAS per- and polyfluoroalkyl substances

SB soil boringUSEPA United States Environmental Protection AgencyQual interpreted qualifier

Depth

Soil, PFAS by LCMSMS compliant with QSM 5.3 Table B-15 (μg/kg)

0 - 2 ft 0 - 2 ft 0 - 2 ft 1 - 3 ft 

Area of Interest AOI0

Location ID AOI01-01 AOI01-01-SB-0-2 (Duplicate) AOI01-02* AOI01-02 

Sample ID AOI01-01-SB-0-2 DUP-01-SB-0-2 AOI01-02-SB-0-2 AOI01-02-SB-1-3 

Sample Date 4/14/2022 4/14/2022 4/14/2022 6/28/2022 

EA Engineering, Science, and Technology, Inc., PBC 
Table 6-2

PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Surface Soil

Site Inspection Report

HAATS

Analyte OSD Screening Level 1

PFBS 1900

PFHxS 130

PFNA 19PFOA 19PFOS 13

NotesGray Fill Detected concentration exceeded OSD Screening Levels*Surface soil sample collected on 4/14/2022 consisted of sediment collecting on asphalt.

A second surface soil sample was collected below the asphalt on 6/28/2022.

References1. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculated

for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA’s

Regional Screening Level Calculator. HQ=0.1. May 2022. The screening levels for soil are

based on residential scenario for incidental ingestion of contaminated soil.

Interpreted QualifiersJ = Estimated concentration.U = The analyte was not detected at a level greater than or equal to the adjusted DL.Acronyms and Abbreviationsμg/kg microgram(s) per kilogramAOI Area of InterestDUP duplicateHAATS High Altitude Army Training SiteHQ Hazard QuotientID identificationLCMSMS liquid chromatography with tandem mass spectrometryLOD limit of detectionLOQ limit of quantitationND analyte not detected above the LOD (LOD values are presented in Appendix F)OSD Office of the Secretary of the DefenseQSM Quality Systems ManualPFAS per- and polyfluoroalkyl substances

SB soil boringUSEPA United States Environmental Protection AgencyQual interpreted qualifier

Depth

Soil, PFAS by LCMSMS compliant with QSM 5.3 Table B-15 (μg/kg)

Area of Interest

Location ID

Sample ID

Sample Date

Result Qual Result Qual Result Qual Re

ND U ND U ND U N

0.62 J 0.41 J 0.51 J 0

ND U ND U ND U N

0.34 J ND U ND U N

22 0.98 2.8 J 7

0 - 2 ft 0 - 2 ft 0 - 2 ft

AOI03 

AOI03-01 

AOI02

AOI02-01 AOI02-02

AOI02-01-SB-0-2 AOI02-02-SB-0-2 AOI03-01-SB-0-2 HA

4/14/2022 4/14/2022 4/14/2022 

EA Engineering, Science, and Technology, Inc., PBC 
Table 6-3

PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Shallow Subsurface Soil

Site Inspection Report

HAATS

Analyte OSD Screening Level 1 Result Qual Result Qual Re

PFBS 25000 ND U ND U NPFHxS 1600 ND U ND U NPFNA 250 ND U ND U NPFOA 250 ND U ND U NPFOS 160 ND U ND U N

Notes Gray Fill Detected concentration exceeded OSD Screening Levels 

References 

1. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculated 

for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA’s 

Regional Screening Level Calculator. HQ=0.1. May 2022. The screening levels for soilare based on Industrial/Commercial Composite Worker scenario for incidental ingestionof contaminated soil.Interpreted Qualifiers

J = The result is an estimated quantity.J-= The result is an estimated quantity, but the result may be biased low.U = The analyte was not detected at a level greater than or equal to the adjusted DL.Acronyms and Abbreviationsμg/kg microgram(s) per kilogramAOI Area of InterestDUP duplicateHAATS High Altitude Army Training SiteHQ Hazard QuotientID identificationLCMSMS liquid chromatography with tandem mass spectrometryLOD limit of detectionLOQ limit of quantitationND analyte not detected above the LOD (LOD values are presented in Appendix F)OSD Office of the Secretary of the DefenseQSM Quality Systems ManualPFAS per- and polyfluoroalkyl substancesSB soil boringUSEPA United States Environmental Protection AgencyQual interpreted qualifier

Sample ID AOI01-01-SB-14-15 AOI01-02-SB-14-15 AO

Location ID AOI01-01 AOI01-02

Area of Interest

Sample Date 6/17/2022

14 - 15 ft 14 - 15 ft 

6/28/2022 

Depth

EA Engineering, Science, and Technology, Inc., PBC 
Table 6-3

PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Shallow Subsurface Soil

Site Inspection Report

HAATS

Analyte OSD Screening Level 1

PFBS 25000PFHxS 1600PFNA 250PFOA 250PFOS 160

NotesGray Fill Detected concentration exceeded OSD Screening LevelsReferences1. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculatedfor PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA’s

Regional Screening Level Calculator. HQ=0.1. May 2022. The screening levels for soilare based on Industrial/Commercial Composite Worker scenario for incidental ingestionof contaminated soil.Interpreted Qualifiers

J = The result is an estimated quantity.J-= The result is an estimated quantity, but the result may be biased low.U = The analyte was not detected at a level greater than or equal to the adjusted DL.Acronyms and Abbreviationsμg/kg microgram(s) per kilogramAOI Area of InterestDUP duplicateHAATS High Altitude Army Training SiteHQ Hazard QuotientID identificationLCMSMS liquid chromatography with tandem mass spectrometryLOD limit of detectionLOQ limit of quantitationND analyte not detected above the LOD (LOD values are presented in Appendix F)OSD Office of the Secretary of the DefenseQSM Quality Systems ManualPFAS per- and polyfluoroalkyl substancesSB soil boringUSEPA United States Environmental Protection AgencyQual interpreted qualifier

Sample ID

Location ID

Area of Interest

Sample Date

Depth

Result Qual Result Qual Res

ND U ND U N

2.6 2.5 N

ND U ND U NND U ND U N

60 J- 48 N

AOI02-01 AOI02-01-SB-14-15 (Duplicate) 

AOI02-01-SB-14-15 HAATS-DUP-02-SB AOI

6/24/2022 6/24/2022 

AOI02

14 - 15 ft 14 - 15 ft 

EA Engineering, Science, and Technology, Inc., PBC 
Table 6-3

PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Shallow Subsurface Soil

Site Inspection Report

HAATS

Analyte OSD Screening Level 1

PFBS 25000PFHxS 1600PFNA 250PFOA 250PFOS 160

NotesGray Fill Detected concentration exceeded OSD Screening LevelsReferences1. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculatedfor PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA’s

Regional Screening Level Calculator. HQ=0.1. May 2022. The screening levels for soilare based on Industrial/Commercial Composite Worker scenario for incidental ingestionof contaminated soil.Interpreted Qualifiers

J = The result is an estimated quantity.J-= The result is an estimated quantity, but the result may be biased low.U = The analyte was not detected at a level greater than or equal to the adjusted DL.Acronyms and Abbreviationsμg/kg microgram(s) per kilogramAOI Area of InterestDUP duplicateHAATS High Altitude Army Training SiteHQ Hazard QuotientID identificationLCMSMS liquid chromatography with tandem mass spectrometryLOD limit of detectionLOQ limit of quantitationND analyte not detected above the LOD (LOD values are presented in Appendix F)OSD Office of the Secretary of the DefenseQSM Quality Systems ManualPFAS per- and polyfluoroalkyl substancesSB soil boringUSEPA United States Environmental Protection AgencyQual interpreted qualifier

Sample ID

Location ID

Area of Interest

Sample Date

Depth

Result Qual Result 

ND U ND ND U ND ND U ND ND U ND ND U ND 

Chemical AbPFBS PFHxS PFNA PFOA PFOS 

HAATS-01 HAAT

HAATS-01-SB-14-15 HAATS-02

14 - 15 ft 14 - 

6/15/2022 6/21/

EA Engineering, Science, and Technology, Inc., PBC 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 6-12

This page intentionally left blank
Table 6-4

PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Deep Subsurface Soil

Site Inspection Report

HAATS

Area of InterestLocation IDSample IDSample Date

Depth

Analyte Result Qual Result Qual Result Qual Result Qual 

PFBS ND U ND U ND U ND U PFHxS ND U ND U ND U ND U PFNA ND U ND U ND U ND U PFOA ND U ND U ND U ND U PFOS ND U ND U ND U ND U 

Notes Chemical AbbreviationsScreening levels are not applied to deep subsurface soil results (>15 feet bgs) because 15 feet is the anticipated limit of construction activities. 

PFBS PFHxS 

Interpreted Qualifiers PFNA 

J = The result is an estimated quantity. PFOA 

U = The analyte was not detected at a level greater than or equal to the adjusted DL. PFOS Acronyms and Abbreviations

μg/kg microgram(s) per kilogramAOI Area of InterestDUP duplicateHAATS High Altitude Army Training SiteHQ Hazard QuotientID identificationLCMSMS liquid chromatography with tandem mass spectrometry

LOD limit of detectionLOQ limit of quantitationND analyte not detected above the LOD (LOD values are presented in Appendix F)OSD Office of the Secretary of the DefenseQSM Quality Systems Manual

PFAS per- and polyfluoroalkyl substancesSB soil boringUSEPA United States Environmental Protection Agency

Qual interpreted qualifier

AOI01-05-SB-84-85 HAATS-01-SB-78-79

6/17/2022 6/23/2022 6/22/2022 6/16/2022 

Soil, PFAS by LCMSMS compliant with QSM 5.3 Table B-15 (μg/kg)

AOI01 HA

74 - 75 ft 74 - 75 ft 84 - 85 ft 78 - 79 ft 

AOI01-01 AOI01-03 AOI01-05 HAATS-01 

AOI01-01-SB-74-75 AOI01-03-SB-74-75

EA Engineering, Science, and Technology, Inc., PBC 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 6-14

This page intentionally left blank
Table 6-5

PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Groundwater

Site Inspection Report

HAATS

Analyte OSD Screening Level 1 Result Qual Result Qual 

PFBS 601 15 ND U 

PFHxS 39 6.3 ND U PFNA 6 ND U ND U PFOA 6 8.0 ND U PFOS 4 ND U ND U 

Notes Chemical AGray Fill Detected concentration exceeded OSD Screening Levels PFBS 

PFHxS 

References PFNA 

1. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculated PFOA  for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA’s PFOS Regional Screening Level Calculator. HQ=0.1 . May 2022. Groundwater screening levelsbased on residential scenario for direct ingestion of groundwater.Interpreted Qualifiers

J = Estimated concentration.J+ = The result is an estimated quantity, but the result may be biased high.J-= The result is an estimated quantity, but the result may be biased low.U = The analyte was not detected at a level greater than or equal to the adjusted DL.UJ = The analyte was not detected at a level greater than or equal to the adjusted DL.  However, the reported adjusted DL is approximate and may be inaccurate or imprecise.Acronyms and AbbreviationsAOI Area of InterestDUP duplicateHAATS High Altitude Army Training SiteHQ Hazard QuotientID identificationLCMSMS liquid chromatography with tandem mass spectrometryLOD limit of detectionLOQ limit of quantitationND analyte not detected above the LOD (LOD values are presented in Appendix F)ng/L nanogram(s) per literOSD Office of the Secretary of the DefenseQSM Quality Systems ManualPFAS per- and polyfluoroalkyl substancesSB soil boringUSEPA United States Environmental Protection AgencyQual interpreted qualifier

Water, PFAS by LCMSMS compliant with QSM 5.3 Table B-15 (ng/l)

Area of Interest 

Sample Date 7/12/2022 6/27/2022 

Sample ID AOI01-02-GW AOI01-03-GW 

Location ID AOI01-02 AOI01-03 

EA Engineering, Science, and Technology, Inc., PBC 
Table 6-5

PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Groundwater

Site Inspection Report

HAATS

Analyte OSD Screening Level 1

PFBS 601PFHxS 39PFNA 6PFOA 6PFOS 4

NotesGray Fill Detected concentration exceeded OSD Screening LevelsReferences1. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculated for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA’s Regional Screening Level Calculator. HQ=0.1 . May 2022. Groundwater screening levelsbased on residential scenario for direct ingestion of groundwater.Interpreted QualifiersJ = Estimated concentration.J+ = The result is an estimated quantity, but the result may be biased high.J-= The result is an estimated quantity, but the result may be biased low.U = The analyte was not detected at a level greater than or equal to the adjusted DL.UJ = The analyte was not detected at a level greater than or equal to the adjusted DL.  However, the reported adjusted DL is approximate and may be inaccurate or imprecise.Acronyms and AbbreviationsAOI Area of InterestDUP duplicateHAATS High Altitude Army Training SiteHQ Hazard QuotientID identificationLCMSMS liquid chromatography with tandem mass spectrometryLOD limit of detectionLOQ limit of quantitationND analyte not detected above the LOD (LOD values are presented in Appendix F)ng/L nanogram(s) per literOSD Office of the Secretary of the DefenseQSM Quality Systems ManualPFAS per- and polyfluoroalkyl substancesSB soil boringUSEPA United States Environmental Protection AgencyQual interpreted qualifier

Water, PFAS by LCMSMS compliant with QSM 5.3 Table B-15 (ng/l)

Area of Interest

Sample Date

Sample ID

Location ID

Result Qual Result Qual Result Qual Result 

ND U ND U 27 1.9 

1.4 J+ 1.1 J 63 4.4 

ND UJ ND U ND U ND 

ND UJ ND U 6.1 ND ND UJ ND U 1.8 J+ ND 

AOI02 

6/29/2022 6/29/2022 6/29/2022 7

AOI02-01-GW HAATS-DUP-02-GW AOI02-02-GW AO

AOI02-01 AOI02-01-GW (Duplicate) AOI02-02 A

EA Engineering, Science, and Technology, Inc., PBC 
!!(

!!(

!!(

!!(

!!(

!(

!(

!(

!(

!(

!(

!(

!(

AOI 2 HAZMAT Storage

Building 1214

AOI 3

Flight Ramp FTA

Flight Ramp

AOI03-01

HAATS-03

HAATS-02

HAATS-01

AOI03-01

AOI02-02 AOI02-01

AOI01-04

AOI01-03

AOI01-02

AOI01-01

AOI01-03-SB-0-2 (Duplicate)

AOI01-01-SB-0-2 (Duplicate)

AOI01-05

0 200

Feet

3

P:\Project\AMEC Inter-Office Projects\3031200026 HAATS\3031200026 HAATS\6-1_PFOSDetectionsinSoil.mxd Service Layer Credits: Source: Esri, Maxar, Earthstar Geographics, and the GIS User Community Facility Data Potential PFAS Release Site No Suspected Release Facility Boundary Area of Interest Notes: PFOS = perfluorooctanesulfonic acid ND = Not Detected (μg/Kg = Microgram(s) per Kilogram Exceedances of the OSD SL are depicted with a yellow halo.

!!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

AOI 2 HAZMAT Storage

Building 1214

AOI 3

Flight Ramp FTA

Flight Ramp

HAATS-01

AOI01-01

AOI01-02

AOI01-04

AOI02-01

AOI02-01-SB-14-15 (Duplicate)

AOI02-02

AOI02-02-SB-14-15 (Duplicate)

HAATS-02-SB-14-15 (Duplicate)

HAATS-02

AOI01-03

AOI03-01

Surface Shallow 

0 200

Feet

Army National Guard Site Inspections

High Altitude Aviation Training Site

Gypsum, Colorado

Figure 6-1

PFOS Detections in Soil

PFOS Results (μg/Kg) 

!( ND

!( >ND - 13

!!( >13 - 250

!!( >250 - 2,500

!!( >2,500
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 6-18

This page intentionally left blank
!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

AOI 2 HAZMAT Storage

Building 1214

AOI 3

Flight Ramp FTA

Flight Ramp

AOI03-01

HAATS-03

HAATS-02

HAATS-01

AOI03-01

AOI02-02 AOI02-01

AOI01-04

AOI01-03

AOI01-02

AOI01-01

AOI01-03-SB-0-2 (Duplicate)

AOI01-01-SB-0-2 (Duplicate)

AOI01-05

0 200

Feet

£

P:\Project\AMEC Inter-Office Projects\3031200026 HAATS\3031200026 HAATS\6-2_PFOADetectionsinSoil.mxd Facility Data No Suspected Release Potential PFAS Release Site Facility Boundary Area of Interest PFOA Results (μg/Kg) !( ND !( >ND - 19 !!( >19 - 160 !!( >160 - 1,600 !!( >1,600 Notes: PFOA = perfluorooctanoic acid ND = Not Detected (μg/Kg = Microgram(s) per Kilogram Exceedances of the OSD SL are depicted with a yellow halo.

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

AOI 2 HAZMAT Storage

AOI 3 Building 1214

Flight Ramp FTA

Flight Ramp

HAATS-01

AOI01-01

AOI01-02

AOI01-04

AOI02-01

AOI02-01-SB-14-15 (Duplicate)

AOI02-02

AOI02-02-SB-14-15 (Duplicate)

HAATS-02-SB-14-15 (Duplicate)

HAATS-02

AOI03-01

AOI01-03

AOI01-05

Surface Shallow 

0 200

Feet

Army National Guard Site Inspections

High Altitude Aviation Training Site

Gypsum, Colorado

Figure 6-2

PFOA Detections in Soil
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 6-20

This page intentionally left blank
!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

AOI 2 HAZMAT Storage

Building 1214

AOI 3

Flight Ramp FTA

Flight Ramp

HAATS-03

HAATS-02

HAATS-01

AOI03-01

AOI02-02 AOI02-01

AOI01-04

AOI01-03

AOI01-02

AOI01-01

AOI01-03-SB-0-2 (Duplicate)

AOI01-01-SB-0-2 (Duplicate)

AOI01-05

0 200

Feet

£

P:\Project\AMEC Inter-Office Projects\3031200026 HAATS\3031200026 HAATS\6-3_PFBSDetectionsinSoil.mxd Explanation: No Suspected Release Potential PFAS Release Site Facility Boundary Area of Interest PFBS Results (μg/Kg) !( ND !( >ND - 10 !( >10 - 1,900 !!( >1,900 - 25,000 !!( >25,000 Notes: PFBS = perfluorobutanesulfonic acid ND = Not Detected (μg/Kg = Microgram(s) per Kilogram Exceedances of the OSD SL are depicted with a yellow halo.

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

AOI 2 HAZMAT Storage

AOI 3 Building 1214

Flight Ramp FTA

Flight Ramp

HAATS-01

AOI01-01

AOI01-02

AOI01-04

AOI02-01

AOI02-01-SB-14-15 (Duplicate)

AOI02-02

AOI02-02-SB-14-15 (Duplicate)

HAATS-02-SB-14-15 (Duplicate)

HAATS-02

AOI03-01

AOI01-03

AOI01-05

Surface Shallow 

0 200

Feet

Army National Guard Site Inspections

High Altitude Aviation Training Site

Gypsum, Colorado

Figure 6-3

PFBS Detections in Soil
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 6-22

This page intentionally left blank
!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

AOI 2 HAZMAT Storage

Building 1214

AOI 3

Flight Ramp FTA

Flight Ramp

HAATS-03

HAATS-02

HAATS-01

AOI03-01

AOI02-02 AOI02-01

AOI01-04

AOI01-03

AOI01-02

AOI01-01

AOI01-03-SB-0-2 (Duplicate)

AOI01-01-SB-0-2 (Duplicate)

AOI01-05

0 200

Feet

£

P:\Project\AMEC Inter-Office Projects\3031200026 HAATS\3031200026 HAATS\6-4_PFHxSDetectionsinSoil.mxd Facility Data No Suspected Release Potential PFAS Release Site Area of Interest Facility Boundary PFHxS Results (μg/Kg) !( ND !( >ND - 10 !( >10 - 130 !!( >130 - 1,600 !!( >1,600 Notes: PFHXs = perfluorohexanesulfonic acid ND = Not Detected (μg/Kg = Microgram(s) per Kilogram Exceedances of the OSD SL are depicted with a yellow halo.

!

!

!

!

!

!

!

!

!

! (

(

(

(

(

(

(

(

(

(

AOI 2 HAZMAT Storage

AOI 3 Building 1214

Flight Ramp FTA

Flight Ramp

HAATS-01

AOI01-01

AOI01-02

AOI01-04

AOI02-01

AOI02-01-SB-14-15 (Duplicate)

AOI02-02

AOI02-02-SB-14-15 (Duplicate)

HAATS-02-SB-14-15 (Duplicate)

HAATS-02

AOI03-01

AOI01-03

AOI01-05

Surface Shallow 

0 200

Feet

Army National Guard Site Inspections

High Altitude Aviation Training Site

Gypsum, Colorado

Figure 6-4

PFHxS Detections in Soil
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 6-24

This page intentionally left blank
!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

AOI 2 HAZMAT Storage

Building 1214

AOI 3

Flight Ramp FTA

Flight Ramp

AOI03-01

HAATS-03

HAATS-02

HAATS-01

AOI03-01

AOI02-02 AOI02-01

AOI01-04

AOI01-03

AOI01-02

AOI01-01

AOI01-03-SB-0-2 (Duplicate)

AOI01-01-SB-0-2 (Duplicate)

AOI01-05

0 200

Feet

3

P:\Project\AMEC Inter-Office Projects\3031200026 HAATS\3031200026 HAATS\6-5_PFNADetectionsinSoil.mxd Service Layer Credits: Source: Esri, Maxar, Earthstar Geographics, and the GIS User Community Facility Data No Suspected Release Potential PFAS Release Site Area of Interest Facility Boundary PFNA Results (μg/Kg) !( ND !( >ND - 19 !!( >19 - 250 !!( >250 - 2,500 !!( >2,500 Notes: PFNA = perfluorononanoic acid ND = Not Detected (μg/Kg = Microgram(s) per Kilogram Exceedances of the OSD SL are depicted with a yellow halo.

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

AOI 2 HAZMAT Storage

AOI 3 Building 1214

Flight Ramp FTA

Flight Ramp

HAATS-01

AOI01-01

AOI01-02

AOI01-04

AOI02-01

AOI02-01-SB-14-15 (Duplicate)

AOI02-02

AOI02-02-SB-14-15 (Duplicate)

HAATS-02-SB-14-15 (Duplicate)

HAATS-02

AOI03-01

AOI01-03

AOI01-05

Surface Shallow 

0 200

Feet

Army National Guard Site Inspections

High Altitude Aviation Training Site

Gypsum, Colorado

Figure 6-5

PFNA Detections in Soil
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 6-26

This page intentionally left blank
!!(

!!(

!!(

!!(

!(

!(

!(

!(

!(

AOI 2 HAZMAT Storage

Building 1214

AOI 3

Flight Ramp FTA

Flight Ramp

AOI02-01-GW (Duplicate)

HAATS-03

HAATS-02

HAATS-01

AOI03-01

AOI02-02 AOI02-01

AOI01-04

AOI01-03

AOI01-02

AOI01-03-GW (Duplicate)

0 200

Feet

3

P:\Project\AMEC Inter-Office Projects\3031200026 HAATS\3031200026 HAATS\6-6_PFOA-PFOS-PFBS_GW.mxd Explanation: No Suspected Release Potential PFAS Release Site Area of Interest Facility Boundary PFOA Results (ng/L) !( ND !( >ND - 6 !!( >6 - 40 !!( >40 - 70 !!( >70 Notes: PFOS = perfluorooctanesulfonic acid PFOA = perfluorooctanoic acid PFBS = perfluorobutanesulfonic acid ND = Not Detected ng/L = Nanogram(s) per Kilogram Exceedances of the OSD SL are depicted with a yellow halo. !!(

!(

!(

!(

!(

!(

!(

!(

!(

AOI 2 HAZMAT Storage

AOI 3 Building 1214

Flight Ramp FTA

Flight Ramp

HAATS-01

AOI01-02

AOI01-04

AOI02-01

AOI02-01-GW (Duplicate)

AOI02-02

HAATS-02

AOI03-01

AOI01-03

AOI01-03-GW (Duplicate)

HAATS-03

PFOA PFOS 

PFOS Results (ng/L)

!( ND

!( >ND - 4

!!( >4 - 40

!!( >40 - 70

!!( >70

0 200Feet 

Army National Guard Site Inspections

High Altitude Aviation Training Site

Gypsum, Colorado

Figure 6-6

PFOA, PFOS, and PFBS Detections in Groundwater
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 6-28

This page intentionally left blank
!!(

!(

!(

!(

!(

!(

!(

!(

!(

AOI 2 HAZMAT Storage

Building 1214

AOI 3

Flight Ramp FTA

Flight Ramp

AOI02-01-GW (Duplicate)

AOI03-01

HAATS-03

HAATS-02

HAATS-01

AOI03-01

AOI02-02 AOI02-01

AOI01-04

AOI01-03

AOI01-02

AOI01-03-GW (Duplicate)

0 200

Feet

3

P:\Project\AMEC Inter-Office Projects\3031200026 HAATS\3031200026 HAATS\6-7_PFHxS-PFNA_GW.mxd Facility Data No Suspected Release Potential PFAS Release Site FacilityBoundary Area of Interest PFHxS Results (ng/L) !( ND !( >ND - 39 !!( >39 - 100 !!( >100 - 1,000 !!( >1,000 Notes: PFHxS =perfluorohexanesulfonic acid PFNA = perfluorononanoic acid ND = Not Detected ng/L = Nanogram(s) per Kilogram Exceedances of the OSD SL are depicted with a yellow halo.

!(

!(

!(

AOI 2 HAZMAT Stora

AOI 

AOI01-03-GW (Dup

AOI

AOI02-02

AOI03-01

PFHxS 

Army National Guard Site Inspections

High Altitude Aviation Training Site

Gypsum, Colorado

Figure 6-7

PFHxS and PFNA Detections in Groundwater

0 200

Feet
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 6-30

This page intentionally left blank
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 7-1

7. EXPOSURE PATHWAYS

The Conceptual Site Model (CSM) for each AOI, revised based on the SI findings, is presented 

on Figure 7-1 through Figure 7-3. Please note that while the CSM discussion assists in 

determining if a receptor may be impacted, the decision to move from SI to RI or interim action 

is determined solely based upon exceedances of the SLs for the relevant compounds and whether 

the release is more than likely attributable to the DoD. A CSM presents the current

understanding of the Facility conditions with respect to known and suspected sources, potential 

transport mechanisms and migration pathways, and potentially exposed human receptors. A 

human exposure pathway is considered potentially complete when the following conditions are 

present:

1. Contaminant source;

2. Environmental fate and transport;

3. Exposure point;

4. Exposure route; and

5. Potentially exposed populations. 

If any of these elements are missing, the pathway is incomplete. The CSM figures use an empty 

circle symbol to represent an incomplete exposure pathway. Areas with no identified complete 

pathway generally warrant no further action. However, the pathway is considered potentially 

complete if the relevant compounds are detected, in which case the CSM figure uses a half-filled 

circle symbol to represent a potentially complete exposure pathway. Additionally, a completely 

filled circle symbol is used to indicate when a potentially complete exposure pathway has 

detections of the relevant compounds above the SLs. Areas with an identified potentially 

complete pathway and a complete pathway may warrant further investigation. Although the 

CSMs indicate whether potentially complete exposure pathways may exist, the recommendation 

for future study in a RI or no action at this time is based on the comparison of the SI analytical 

results for the relevant compounds to the SLs.

In general, the potential routes of exposure to the relevant compounds are ingestion and 

inhalation. Human exposure via the dermal contact pathway may occur, and current risk practice 

suggests it is an insignificant pathway compared to ingestion; however, exposure data for dermal 

pathways are sparse and continue to be the subject of toxicological study. The receptors 

evaluated are consistent with those listed in EPA guidance for risk screening (EPA 2001). Based 

on the synoptic water level measurements made during the SI, there are three commercial wells 

that are potentially downgradient of the Facility. One of the commercial wells is located on the 

property just north of the facility that is currently being used to mine gravel. Commercial well 

permits allow for commercial use that includes drinking and sanitation facilities inside a business 

(Colorado Division of Water Resources, 2023). The commercial well user is considered a 

potential off-Facility receptor. Due to the facility being secured, trespassers are not considered a 

potential receptor at this Facility. Receptors at the Facility include site workers (e.g., Facility

staff and visiting soldiers) and construction workers. Off-facility residents, commercial well 

users, and recreational users are receptors located outside the Facility boundary.
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 7-2

7.1 SOIL EXPOSURE PATHWAY

The SI results in soil were used to determine whether a potentially complete pathway exists 

between the source and potential receptors at each AOI based on the aforementioned criteria. 

7.1.1 AOI 1

AOI 1 includes the Facility parking apron and taxiway where potential PFAS releases may have 

occurred. Although no PFAS releases are known to have occurred since the construction of the 

Facility in 2013, the storage of Tri-MaxTM units outdoors on the parking apron and the history of 

water salutes performed at the AOI may have led to environmental releases of AFFF (AECOM, 

2020).

PFOS was detected in surface soil at AOI 1 above its SL. PFOA, PFNA, and PFHxS were 

detected in surface soil at AOI 1 below their respective SLs. Site workers and construction 

workers could potentially be exposed to relevant compounds in surface soil via incidental 

ingestion and inhalation of dust; therefore, the surface soil exposure pathways are potentially 

complete for these receptors. As the resident, commercial well user, and recreational user are 

potential off-Facility receptors, there are no complete exposure pathways to relevant compounds 

in surface soil (inhalation of dust for off-Facility receptors is likely insignificant). Relevant 

compounds were not detected in shallow or deep subsurface samples at AOI 1; therefore, the 

subsurface soil exposure pathway is incomplete. The CSM for AOI 1 is presented on Figure 7-

1.

7.1.2 AOI 2 

AOI 2 includes the Facility HAZMAT storage area where potential PFAS releases may have 

occurred. Although no PFAS releases are known to have occurred since the construction of

the Facility in 2013, the storage of one Tri-MaxTM unit outdoors in the HAZMAT storage area 

may have led to environmental releases of AFFF (AECOM, 2020).

PFOS was detected in surface soil at AOI 2 above its SL. PFOA and PFHxS, were detected in 

surface soil at AOI 2 below their respective SLs. Site workers and construction workers could 

potentially be exposed to relevant compounds in surface soil via incidental ingestion and 

inhalation of dust therefore, the surface soil exposure pathways are potentially complete for these 

receptors. PFOS and PFHxS were detected in shallow subsurface soil below their respective SLs; 

therefore, the subsurface soil pathway is potentially complete for construction workers at the 

Facility (due to potential excavation activities). It is not anticipated that the site worker would 

conduct excavation activities, therefore the exposure pathway to relevant compounds in 

subsurface soil for site workers is incomplete. As the resident, commercial well user, and 

recreational user are potential off-Facility receptors, there are no complete exposure pathways to 

relevant compounds in surface soil or subsurface soil (inhalation of dust for off-Facility receptors 

is likely insignificant). The CSM for AOI 2 is presented in Figure 7-2.
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 7-3

7.1.3 AOI 3

AOI 3 comprises Building 1214 and the Flight Ramp FTA. Building 1214 was constructed with

an AFFF suppression system that contains Buckeye Premium 3% Military Specification AFFF

concentrate. The building also stores one 55-gallon drum containing the same AFFF product. No

known AFFF releases have occurred at Building 1214 since its construction, but it is

conservatively considered an AOI based on the potential for undocumented releases (AECOM

2020). The Flight Ramp FTA is located in the northeast corner of the Flight Ramp, just south of

Building 1214. While there was no documented use of AFFF at the Flight Ramp FTA, it has

been incorporated into AOI 3 due to the historic use of AFFF at FTAs in general.

PFOS and PFHxS were detected in surface soil at AOI 3 below their respective SLs. Site 

workers and construction workers could potentially be exposed to relevant compounds in surface 

soil via incidental ingestion and inhalation of dust; therefore, the surface soil exposure pathway 

is potentially complete for these receptors. As the resident, commercial well user, and 

recreational user are potential off-Facility receptors, there are no complete exposure pathways to 

relevant compounds in surface soil (inhalation of dust for off-Facility receptors is likely 

insignificant). Relevant compounds were not detected in shallow or deep subsurface samples at 

AOI 3; therefore, the subsurface soil exposure pathway is incomplete. The CSM for AOI 3 is 

presented in Figure 7-3.

7.2 GROUNDWATER EXPOSURE PATHWAY

The SI results in groundwater were used to determine whether a potentially complete pathway 

exists between the source and potential receptors at each AOI based on the aforementioned 

criteria. 

Potable and non-potable water are provided to EGE and its tenants (including the Facility) 

through the Town of Gypsum; no onsite wells provide drinking water to COARNG personnel. 

Potable and non-potable water is provided to EGE and its tenants through the Town of Gypsum. 

There are no water wells located at the Facility. Potable water is used for drinking water at 

HAATS, and non-potable water is strictly used for irrigation. The water is owned by the Town of 

Gypsum and stored in various large water tanks throughout the town. The Norgaard Water 

Treatment Plant and associated intake point is located on Gypsum Creek upstream of the 

confluence of Gypsum Creek and Eagle River. Based on the synoptic water level measurements 

made during the SI, the intake point is likely cross-gradient of the Facility. The locations of the 

Eagle River intake and the T2 well (identified in the 2016 town water quality report) are 

unknown (AECOM, 2020). Based on the synoptic water level measurements made during the SI, 

there are three commercial wells that are potentially downgradient of the Facility. One of the 

commercial wells is located on the property just north of the facility that is currently being used 

to mine gravel. Commercial well permits allow for commercial use that includes drinking and 

sanitation facilities inside a business (Colorado Division of Water Resources, 2023). The 

commercial well user is considered a potential off-Facility receptor. 

Depths to groundwater measured at the Facility in July 2022 during the SI ranged from 76.91 to 

82.03 feet bgs. Accidental ingestion of groundwater by construction workers during grounddisturbing activities is considered 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 7-4

7.2.1 AOI 1

PFOA was detected in groundwater at AOI 1 above its SL. PFBS and PFHxS were detected in 

groundwater at AOI 1 below their respective SLs. Due to the presence of the off-Facility 

commercial wells discussed above, the pathway for exposure to off-Facility commercial well 

users via ingestion of groundwater is considered potentially complete. The Eagle River is located 

approximately 0.5 miles to the north (downgradient) of the Facility. It is not known if there is 

offsite groundwater discharge to surface water bodies (the Eagle River or its tributaries). Based 

on the depth to groundwater and the elevation of the Eagle River, groundwater interaction with 

the river may be possible downgradient of the Facility, the ingestion exposure pathway for 

offsite surface water and sediment is considered potentially complete for recreational users of the 

river. The area of Eagle River that is downgradient of the Facility does not appear to be upstream 

of the known locations of the Town of Gypsum water intakes, therefore, the exposure pathway 

for the ingestion of groundwater is not complete for the site worker, construction worker, or 

resident. The CSM for AOI 1 is presented on Figure 7-1. 

7.2.2 AOI 2

PFOA and PFHxS were detected in groundwater at AOI 2 above their respective SLs. PFOS and 

PFBS were detected in groundwater at AOI 2 below their respective SLs. Due to the presence of 

the off-Facility commercial wells discussed above, the pathway for exposure to off-Facility

commercial well users via ingestion of groundwater is considered potentially complete. The 

Eagle River is located approximately 0.5 miles to the north (downgradient) of the Facility. It is 

not known if there is offsite groundwater discharge to surface water bodies (the Eagle River or 

its tributaries). Based on the depth to groundwater and the elevation of the Eagle River, 

groundwater interaction with the river may be possible downgradient of the Facility, the 

ingestion exposure pathway for offsite surface water and sediment is considered potentially 

complete for recreational users of the river. The area of Eagle River that is downgradient of the 

Facility does not appear to be upstream of the known locations of the Town of Gypsum water 

intakes, therefore, the exposure pathway for the ingestion of groundwater is not complete for the 

site worker, construction worker, or resident. The CSM for AOI 2 is presented on Figure 7-2. 

7.2.3 AOI 3

PFHxS and PFBS were detected in groundwater at AOI 3 below their respective SLs. Due to the 

presence of the off-Facility commercial wells discussed above, the pathway for exposure to offFacility commercial well users via ingestion of groundwater is considered potentially complete. 

The Eagle River is located approximately 0.5 miles to the north (downgradient) of the Facility. It 

is not known if there is offsite groundwater discharge to surface water bodies (the Eagle River or 

its tributaries). Based on the depth to groundwater and the elevation of the Eagle River, 

groundwater interaction with the river may be possible downgradient of the Facility, the 

ingestion exposure pathway for offsite surface water and sediment is considered potentially 

complete for recreational users of the river. The area of Eagle River that is downgradient of the 

Facility does not appear to be upstream of the known locations of the Town of Gypsum water 

intakes, therefore, the exposure pathway for the ingestion of groundwater is not complete for the 

site worker, construction worker, or resident. The CSM for AOI 3 is presented in Figure 7-3. 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 7-5

7.3 SURFACE WATER AND SEDIMENT EXPOSURE PATHWAY

Surface water at HAATS is limited to drainage ditches that intermittently contain water. 

Additionally, there are stormwater inlets on the north side of Building 1214 that discharge to a 

low point at the north Facility boundary. Another stormwater inlet is located in a low point north 

of the apron which flows toward a ditch on the east side of the apron. The stormwater system 

ultimately flows north towards the Eagle River. No surface water or sediment samples were 

collected as part of the SI.

7.3.1 AOI 1

PFOS was detected in surface soil at AOI 1 above its SL. PFOA, PFNA, and PFHxS were 

detected in surface soil at AOI 1 below their respective SLs. Due to the presence of relevant 

compounds in surface soil, there is the potential for stormwater to transport PFAS-impacted soil 

particles to the Eagle River and expose the potential recreational user by ingestion of surface 

water. There is also potential for a construction worker to be exposed while completing ground 

maintenance at the site. The CSM for AOI 1 is presented on Figure 7-1.

7.3.2 AOI 2

PFOS was detected in surface soil at AOI 2 above its SL. PFOA and PFHxS were detected in 

surface soil at AOI 2 below their respective SLs. Due to the presence of relevant compounds in 

surface soil, there is the potential for stormwater to transport PFAS-impacted soil particles to the 

Eagle River and expose the potential recreational user by ingestion of surface water. There is 

also potential for a construction worker to be exposed while completing ground maintenance at 

the site. The CSM is presented in Figure 7-2. 

7.3.1 AOI 3

PFOS and PFHxS were detected in surface soil at AOI 3 below their respective SLs. Due to the 

presence of relevant compounds in surface soil, there is the potential for stormwater to transport 

PFAS-impacted soil particles to the Eagle River and expose the potential recreational user by 

ingestion of surface water. There is also potential for a construction worker to be exposed while 

completing ground maintenance at the site. The CSM is presented in Figure 7-3.
Notes:

1. The resident and recreational user refers to 

off-site receptors.

2. Inhalation of dust for off-site receptors is 

highly unlikely. Figure 7-1

Conceptual Site Model

HAATS

RECEPTO

Human Receptors

Current/Future

Site 

Worker

Construction 

Worker Resident1,2 

AOI 1

PFAS in 

surface soil 

and 

groundwater

Human 

Activities

Precipitation/

Run-Off

Leaching/

Infiltration

Airborne 

Soil 

Particulate

Surface Soil 

at AOI

Surface 

Water/ 

Sediment

Subsurface 

Soil

Shallow 

Groundwater

Ingestion

Ingestion

Ingestion

Ingestion

Potential 

Off-Facility 

Source Not 

under 

Control of 

ARNG

Potential releases 

from Tri-Max 

extinguisher storage 

and water salutes

SOURCE

Source Release Mechanism Media

PATHWAY

Transport

and Migration Media Exposure Routes

Inhalation 

of Dust

Site 

Worker

Construction 

Worker

LEGEND

Flow Chart ContinuesIncomplete PathwayPotentially Complete PathwayPotentially Complete Pathway with Exceedance of SL

Resident1,2 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 7-7

This page intentionally left blank
Notes:

1. The resident and recreational user refers to 

off-site receptors.

2. Inhalation of dust for off-site receptors is 

highly unlikely. Figure 7-2

Conceptual Site Model

HAATS

RECEPTO

Human Receptors

Current/Future

Site 

Worker

Construction 

Worker Resident1,2 

AOI 2

PFAS in 

surface soil 

and 

groundwater

Human 

Activities

Precipitation/

Run-Off

Leaching/

Infiltration

Airborne 

Soil 

Particulate

Surface Soil 

at AOI

Surface 

Water/ 

Sediment

Subsurface 

Soil

Shallow 

Groundwater

Ingestion

Ingestion

Ingestion

Ingestion

Potential 

Off-Facility 

Source Not 

under 

Control of 

ARNG

Potential releases 

from Tri-Max 

extinguisher storage

SOURCE

Source Release Mechanism Media

PATHWAY

Transport

and Migration Media Exposure Routes

Inhalation 

of Dust

Site 

Worker

Construction 

Worker

LEGEND

Flow Chart ContinuesIncomplete PathwayPotentially Complete PathwayPotentially Complete Pathway with Exceedance of SL

Resident1,2 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 7-9

This page intentionally left blank
Notes:

1. The resident and recreational user refers to 

off-site receptors.

2. Inhalation of dust for off-site receptors is 

highly unlikely. Figure 7-3

Conceptual Site Model

HAATS

RECEPTO

Human Receptors

Current/Future

Site 

Worker

Construction 

Worker Resident1,2 

AOI 3

PFAS in 

surface soil 

and 

groundwater

Human 

Activities

Precipitation/

Run-Off

Leaching/

Infiltration

Airborne 

Soil 

Particulate

Surface Soil 

at AOI

Surface 

Water/ 

Sediment

Subsurface 

Soil

Shallow 

Groundwater

Ingestion

Ingestion

Ingestion

Ingestion

Potential 

Off-Facility 

Source Not 

under 

Control of 

ARNG

Potential releases 

from Building 1214 

or Flight Ramp FTA

SOURCE

Source Release Mechanism Media

PATHWAY

Transport

and Migration Media Exposure Routes

Inhalation 

of Dust

Site 

Worker

Construction 

Worker

LEGEND

Flow Chart ContinuesIncomplete PathwayPotentially Complete PathwayPotentially Complete Pathway with Exceedance of SL

Resident1,2 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 7-11

This page intentionally left blank
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 8-1

8. SUMMARY AND OUTCOME

This section summarizes SI activities and findings. The most significant findings are summarized 

in this section and are reproduced directly or abstracted from information contained in this 

report. The outcome provides general and comparative interpretations of the findings relative to 

the SLs. 

8.1 SI ACTIVITIES

The SI field activities at the Facility were conducted over two field events: from 13 to 14 April 

2022, and from 7 June to 14 July 2022. The SI field activities included soil and groundwater

sampling. Field activities were conducted in accordance with the UFP-QAPP Addendum 

(EA/Wood, 2022), except as previously noted in Section 5.9.

To fulfill the project DQOs set forth in the approved SI UFP-QAPP Addendum (EA/Wood,

2022), samples were collected and analyzed for 24 compounds by LC/MS/MS compliant with 

QSM 5.3 Table B-15 as follows. 

• Twenty-seven (27) soil samples from 11 locations (soil borings locations);

• Nine (9) grab groundwater samples from 11 temporary well locations;

• Fifty-one (51) QA/QC samples. 

An SI is conducted when the PA determines an AOI exists based on probable use, storage, and/or 

disposal of PFAS-containing materials. The SI includes multi-media sampling at AOIs to 

determine whether or not a release has occurred. The SI may conclude further investigation is 

warranted, a removal action is required to address immediate threats, or no further action is 

required. Additionally, the CSMs were refined to assess whether a potentially complete pathway 

exists between the source and potential receptors for potential exposure at the AOIs, which are 

described in Section 7. 

8.2 OUTCOME

Based on the results of this SI, further evaluation is warranted for AOIs 1 and 2. Further 

evaluation is not warranted for AOI 3 (see Table 8-1). Based on the CSMs developed and 

revised based on the SI findings, there is potential for exposure to site workers and construction 

workers that could contact constituents in surface soil at the AOIs via incidental ingestion and 

inhalation of dust, and there is a potential for exposure to construction workers at AOI 2 that may 

contact constituents in sub-surface soil. Additionally, groundwater, which exceeded SLs at AOI 

1, AOI 2, and in upgradient temporary monitoring wells, may flow towards nearby off-Facility 

water wells.

Sample analytical concentrations collected during the SI were compared against the project SLs 

in soil and groundwater, as described in Table 6-1. The following bullets summarize the SI 

results relative to the SLs: 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 8-2

At AOI 1:

• PFOS was detected in surface soil at concentrations exceeding the SL. PFOS was detected in 

surface soil at four of the five AOI 1 sample locations and exceeded the SL at three locations

with a maximum concentration of 38 μg/kg. PFHxS, PFNA, and PFOA were detected in 

surface soil at concentrations below their respective SLs. PFHxS, PFOA, PFOS, PFBS, and 

PFNA were not detected in any of the shallow or the deep subsurface soil samples.

• PFOA was detected in groundwater at one of the three AOI 1 sample locations and exceeded 

the SL with a concentration of 8 ng/L. PFBS and PFHxS were detected in groundwater at 

concentrations below their respective SLs.

• Relevant compounds were detected in temporary monitoring wells located upgradient of 

AOI 1, suggesting a potential upgradient source. PFOS exceeded its SL at one of the three 

groundwater sample locations, and PFOA exceeded its SL at two of the three groundwater 

sample locations. PFBS, PFHxS, and PFNA were detected at concentrations below their 

respective SLs at one or more of the three upgradient wells. 

• Based on exceedances of the SLs in surface soil and groundwater, further evaluation of 

AOI 1 is warranted in the RI.

At AOI 2:

• PFOS was detected in surface soil at concentrations exceeding the SL. PFOS was detected in 

surface soil at both AOI 2 sample locations and exceeded the SL at one location with a 

maximum concentration of 22 μg/kg. PFOA and PFHxS were detected in surface soil at 

concentrations below their respective SLs. PFOS and PFHxS were also detected in shallow 

subsurface soil at concentrations below their respective SLs.

• PFOA and PFHxS were detected in groundwater at concentrations exceeding their respective 

SLs. PFOA was detected in groundwater at one of the two AOI 2 sample locations and

exceeded the SL with a concentration of 6.1 ng/L. PFHxS was detected in groundwater at 

both of the AOI 2 sample locations and exceeded the SL at one location with a concentration 

of 63 ng/L. PFBS and PFOS were detected in groundwater at concentrations below their 

respective SLs.

• Based on the exceedances of the SLs in soil and groundwater, further evaluation at AOI 2 is 

warranted. 

At AOI 3:

• PFOS and PFHxS were detected in surface soil at concentrations below their respective SLs. 

PFOA, PFNA, and PFBS were not detected in the surface soil samples. PFOA, PFOS, 

PFHxS, PFNA, and PFBS were not detected in the shallow subsurface soil sample.

• PFHxS and PFBS were detected in groundwater at concentrations below their respective SLs.
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 8-3 

• Therefore, further evaluation at AOI 3 is not warranted. 

Of the six PFAS compounds presented in the 6 July 2022 OSD memorandum, HFPO-DA 

(commonly referred to as GenX) was not included as an analyte at the time of this SI. Based on 

the CSM developed during the PA and revised based on SI findings, the presence of HFPO-DA 

is not anticipated at the facility because HFPO-DA is generally not a component of MIL-SPEC 

AFFF and based on its history including distribution limitations that restricted use of GenX, it is 

generally not a component of other products the military used. In addition, it is unlikely that 

GenX would be an individual chemical of concern in the absence of other PFAS.

Table 8-1 summarizes the SI results for soil and groundwater used to determine if an AOI should 

be considered for further investigation under CERCLA and undergo an RI. 

Table 8-1. Summary of Site Inspection Findings and Recommendations

AOI

Potential Release 

Area

Soil – 

Source Area

Groundwater – 

Source Area

Groundwater – 

Facility Boundary Future Action

1

Parking 

Apron/Taxiway Proceed to RI

2

HAZMAT Storage 

Area NA Proceed to RI

3 Building 1214 NA No further action

Legend:

 = Detected; exceedance of screening levels

 = Detected; no exceedance of screening levels

 = Not detected
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 8-4

This page intentionally left blank
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 9-1

9. REFERENCES

AECOM. 2020. Final Preliminary Assessment Report, HAATS, Gypsum. August.

AMEC, 2010. Phase I Environmental Site Assessment; Facility – Gypsum, Colorado.

April 2010.

Assistant Secretary of Defense. 2022. Investigating Per- and Polyfluoroalkyl Substances within 

the Department of Defense Cleanup Program. United States Department of Defense. 6 

July.

Barkmann, Peter E., Lauren D. Broes, Martin J. Palkovic, John C. Hopkins, Kenneth Swift Bird, 

Lesley A. Sebol, and F. Scot Fitzgerald, 2020. ON-010 Colorado Groundwater Atlas. 

Geohydrology. January 8, 2020. 

https://coloradogeologicalsurvey.org/water/coloradogroundwater-atlas/. (Accessed 

February 2020).

COARNG, 2017. Spill Prevention, Control and Countermeasure Plan; High Altitude Aviation 

Training Site. August 2017.

Colorado Division of Water Resources. 2023. Beginner’s Guide to Well Permits. February. 

Department of the Army (DA). 2016a. EM-200-1-2, Environmental Quality, Technical Project 

Planning Process. 29 February.

. 2016b. Army Guidance to Address Perfluorooctane Sulfonate (PFOS) and 

Perfluorooctanoic Acid (PFOA) Contamination. August.

. 2018. Army Guidance for Addressing Releases of Per-and Polyfluoroalkyl Substances.

September.

DoD. 2019a. Department of Defense (DoD), Department of Energy (DOE) Consolidated Quality

Systems Manual (QSM) for Environmental Laboratories, Version 5.3. May.

. 2019b. General Data Validation Guidelines. November.

. 2020. Data Validation Guidelines Module 3: Data Validation Procedure for Per- and 

Polyfluoroalkyl Substances Analysis by QSM Table B-15. May.

EA, Engineering, Science, and Technology, PBC (EA). 2020. Final Programmatic Uniform 

Federal Policy Quality Assurance Project Plan, Site Inspections for Per- and 

Polyfluoroalkyl Substances Impacted Sites, ARNG Installations, Nationwide. December.

EA Engineering, Science, and Technology, PBC and Wood Environment & Infrastructure 

Solutions, Inc. (EA/Wood). 2021. Accident Prevention Plan/Site Safety and Health Plan 

Addendum, Site Inspections for Per- and Polyfluoroalkyl Substances Impacted Sites, 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 9-2

ARNG Installations, Nationwide, High Altitude Aviation Training Site, Gypsum, 

Colorado. November.

.2022. Final Site Inspection Uniform Federal Policy Quality Assurance Project Plan 

(UFP-QAPP) Addendum, High Altitude Aviation Training Site, Gypsum, Colorado, Perand Polyfluoroalkyl Substances Impacted Sites, ARNG Installations, Nationwide. 

January.

EGE, 2014. Eagle County Regional Airport Master Plan. February 11, 2014. 

https://www.flyvail.com/about/master-plan. (Accessed January 2020).

Guelfo, J.L. and C.P. Higgins. 2013. Subsurface transport potential of perfluoroalkyl acids and 

aqueous film-forming foam (AFFF)-impacted sites. Environmental Science and 

Technology 47(9):4164-71. 

Higgins, C.P., and R.G. Luthy. 2006. Sorption of perfluorinated surfactants on sediments. 

Environmental Science and Technology 40 (23): 7251-7256. 

ITRC. 2018. Environmental Fate and Transport for Per- and Polyfluoroalkyl Substances. 

March. 

U.S. Environmental Protection Agency (EPA). 1980. Comprehensive Environmental Response,

Compensation, and Liability Act (CERCLA). 11 December.

. 1994. National Oil and Hazardous Substances Pollution Contingency Plan (Final Rule).

40 Code of Federal Regulations Part 300; 59 Federal Register 47384. September.

. 2001. Risk Assessment Guidance for Superfund, Volume I: Human Health Evaluation

Manual (Part D, Standardized Planning, Reporting, and Review of Superfund Risk 

Assessments). December.

. 2005. Federal Facilities Remedial Site Inspection Summary Guide. July.

. 2006. Guidance on Systematic Planning Using the Data Quality Objectives Process

USEPA/240/B-06/001. February.

. 2017. National Functional Guidelines for Organic Superfund Data Review. OLEM 

9355.0-136, EPA-540-R-2017-002. Office of Superfund Remediation and Technology 

Innovation. January.

U.S. Fish and Wildlife Service (USFWS). 2022. Endangered Species. http://ecos.fws.gov/ipac/. 

Accessed 10 October.

Xiao, F., M. F. Simcik, T.R. Halbach, and J.S Gulliver. 2015, Perfluorooctane sulfonate (PFOS) 

and perfluorooctanoate (PFOA) in soils and groundwater of a U.S. metropolitan area: 

Migration and implications for human exposure. Water Research 72:64-74. 
Site Inspection Report

High Altitude Aviation Training Site, Colorado Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 9-3

This page intentionally left blank