FINAL

Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

Perfluorooctanesulfonic acid (PFOS) and 

Perfluorooctanoic acid (PFOA) at Impacted Sites

ARNG Installations, Nationwide

September 2020

Prepared for:

Army National Guard Bureau

111 S. George Mason Drive

Arlington, VA 22204

UNCLASSIFIED
PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

i

Table of Contents

Executive Summary .................................................................................................................... 1

1. Introduction ........................................................................................................................ 3

1.1 Authority and Purpose .............................................................................................. 3

1.2 Preliminary Assessment Methods ............................................................................. 3

1.3 Report Organization .................................................................................................. 4

1.4 Facility Location and Description............................................................................... 4

1.5 Facility Environmental Setting ................................................................................... 5

1.5.1 Geology ......................................................................................................... 5

1.5.2 Hydrogeology ................................................................................................. 5

1.5.3 Hydrology ....................................................................................................... 6

1.5.4 Climate ........................................................................................................... 6

1.5.5 Current and Future Land Use ......................................................................... 6

2. Fire Training Areas ........................................................................................................... 10

3. Non-Fire Training Areas ................................................................................................... 11

4. Emergency Response Areas ............................................................................................ 12

5. Adjacent Sources ............................................................................................................. 13

6. Preliminary Conceptual Site Model .................................................................................. 14

7. Conclusions ..................................................................................................................... 15

7.1 Findings .................................................................................................................. 15

7.2 Uncertainties ........................................................................................................... 15

7.3 Potential Future Actions .......................................................................................... 16

8. References ...................................................................................................................... 18
PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

ii

Figures

Figure ES-1 Summary of Findings

Figure 1-1 Facility Location

Figure 1-2 Groundwater Features

Figure 1-3 Surface Water Features

Figure 7-1 Summary of Findings

Tables

Table 7-1 Summary of Uncertainties

Appendices

Appendix A Data Resources

Appendix B Preliminary Assessment Documentation

B.1 Interview Records

B.2 Visual Site Inspection Checklists

B.3 Conceptual Site Model Information

Appendix C Photographic Log
PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

iii

Acronyms and Abbreviations

°F degrees Fahrenheit

AECOM AECOM Technical Services, Inc.

AFFF aqueous film forming foam

amsl above mean sea level

AOI area of interest

ARNG Army National Guard

CERCLA Comprehensive Environmental Response, Compensation, and Liability

Act

CFR Code of Federal Regulations

CSM conceptual site model

EDR TM Environmental Data Resource, Inc. TM

FTA fire training area

HA Health Advisory

HIARNG Hawaiʻi Army National Guard

mg/L Cl- milligrams of chloride per liter

NRCS Natural Resources Connservation Service

PA Preliminary Assessment

PFAS per- and poly-fluoroalkyl substances

PFOA perfluorooctanoic acid

PFOS perfluorooctanesulfonic acid

SI Site Inspection

UCMR3 Unregulated Contaminant Monitoring Rule 3

UIC underground injection control

US United States

USACE United States Army Corps of Engineers

USACHPPM United States Army Center for Health Promotion and Preventative

Medicine

USDA United States Department of Agriculture

USEPA United States Environmental Protection Agency

USGS United States Geological Survey

VSI visual site inspection
PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

1

Executive Summary

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

Inspections (SIs) for Perfluorooctanesulfonic acid (PFOS) and Perfluorooctanoic acid (PFOA)

Impacted Sites at ARNG Facilities Nationwide. A PA for per- and polyfluoroalkyl substances

(PFAS)-containing materials was completed for Fort Ruger (also referred to as the “facility”) in

Honolulu, Oʻahu, Hawaiʻi, to assess potential PFAS release areas and exposure pathways to

receptors. Occupation of the property by Hawaiʻi ARNG (HIARNG) began in 1948. The

performance of this PA included the following tasks:

· Reviewed available administrative record documents and Environmental Data Resources,

Inc. (EDR)TM report packages to obtain information relevant to potential PFAS releases, such

as: drinking water well locations, historical aerial photographs, Sanborn maps, and

environmental compliance actions in the area surrounding the facility;

· Conducted a site visit on 1 May 2019 and completed visual site inspections at locations where

PFAS-containing materials were suspected of being stored, used, or disposed; 

· Interviewed former Fort Ruger personnel on 30 April 2019, including former mechanics and

electronics personnel.

No known or documented releases of PFAS to the environment were identified at the facility during

the preparation of this PA report.

Based on the PA findings regarding historical activities concerning aqueous film forming foam use

and storage at the facility, there is no potential for exposure to PFAS contamination in soil,

groundwater, surface water, and sediment (Figure ES-1). Based on the United States (US)

Environmental Protection Agency (USEPA) Unregulated Contaminant Monitoring Rule 3

(UCMR3) data, it was indicated that no PFAS were detected in a public water system above the

USEPA’s lifetime Health Advisory (HA) within 20 miles of the facility. The HA is 70 parts per trillion

for PFOS and PFOA, individually or combined. PFAS analyses performed in 2016 had method

detection limits that were higher than currently achievable. Thus, it is possible that low

concentrations of PFAS were not detected during the UCMR3 but might be detected if analyzed

today.
Fort Ruger

CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

ST

9/10/2020

9/10/2020

Preliminary Assessment for PFAS at Fort Ruger, HI

9/10/2020

1:12,000 ­ Figure ES-1 PM RG 9/10/2020

12420 Milestone Center Drive

Germantown, MD 20876

Summary of Findings

Base Map: Source: Esri, Maxar, GeoEye, Earthstar

Geographics, CNES/Airbus DS, USDA, USGS,

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\HI\Ft_Ruger_Figures\Fig_ES-1_Ft_Ruger_Summary.mxd

0 500 1,000 2,000

Feet

Legend

No Suspected Release

Facility Boundary

Water Body

Wetland

Diamond Head 

State Monument

2
PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

3

1. Introduction

1.1 Authority and Purpose

The Army National Guard (ARNG) G9 is the lead agency in performing Preliminary Assessments

(PAs) and Site Inspections (SIs) for Perfluorooctanesulfonic acid (PFOS) and Perfluorooctanoic

acid (PFOA) at Impacted Sites at ARNG Facilities Nationwide. This work is supported by the

United States (US) Army Corps of Engineers (USACE) Baltimore District and their contractor

AECOM Technical Services, Inc. (AECOM) under Contract Number W912DR-12-D-0014, Task

Order W912DR17F0192, issued 11 August 2017.

The ARNG is assessing potential effects on human health related to processes at facilities that

used per- and poly-fluoroalkyl substances (PFAS) (a suite of related chemicals), primarily in the

form of aqueous film forming foam (AFFF) released as part of firefighting activities, although other

PFAS sources are possible. In addition, the ARNG is assessing businesses or operations adjacent

to the ARNG facility (not under the control of ARNG) that could potentially be responsible for a

PFAS release.

PFAS are classified as emerging environmental contaminants that are garnering increasing

regulatory interest due to their potential risks to human health and the environment. PFAS

formulations contain highly diverse mixtures of compounds. Thus, the fate of these PFAS

compounds in the environment varies. The regulatory framework at both federal and state levels

continues to evolve. The US Environmental Protection Agency (USEPA) issued a lifetime Drinking

Water Health Advisory (HA) for PFOA and PFOS in May 2016, but there are currently no

promulgated national standards regulating PFAS in drinking water. The HA is 70 parts per trillion

for PFOS and PFOA, individually or combined.

This report presents findings of a PA for PFAS-containing materials at Fort Ruger (also referred

to as the “facility”) in Honolulu, Oʻahu, Hawaiʻi in accordance with the Comprehensive

Environmental Response, Compensation, and Liability Act (CERCLA), as amended, the National

Oil and Hazardous Substances Pollution Contingency Plan (40 Code of Federal Regulations

[CFR] Part 300), and Army requirements and guidance.

This PA documents the locations where PFAS may have been released into the environment at

Fort Ruger. The term PFAS will be used throughout this report to encompass all PFAS chemicals

being evaluated, including PFOS and PFOA, which are key components of AFFF.

1.2 Preliminary Assessment Methods

The performance of this PA included the following tasks:

· Reviewed available administrative record documents and Environmental Data Resources,

Inc. (EDR)TM report packages to obtain information relevant to potential PFAS releases, such

as: drinking water well locations, historical aerial photographs, Sanborn maps, and

environmental compliance actions in the area surrounding the facility; 

· Conducted a site visit on 1 May 2019 and completed visual site inspections (VSIs) at locations

where PFAS-containing materials were suspected of being stored, used, or disposed; 

· Interviewed former Fort Ruger personnel on 30 April 2019, including former mechanics and

electronics personnel.
PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

4

1.3 Report Organization

This report has been prepared in accordance with the USEPA Guidance for Performing

Preliminary Assessments under CERCLA (USEPA, 1991). The report sections and descriptions

of each are as follows:

· Section 1 – Introduction: identifies the project purpose and authority and describes the

facility location, environmental setting, and methods used to complete the PA.

· Section 2 – Fire Training Areas: describes the fire training areas (FTAs) at the facility

identified during the site visit.

· Section 3 – Non-Fire Training Areas: describes other locations of potential PFAS releases

at the facility identified during the site visit.

· Section 4 – Emergency Response Areas: describes areas of potential PFAS release at the

facility, specifically in response to emergency situations.

· Section 5 – Adjacent Sources: describes sources of potential PFAS release adjacent to the

facility that are not under the control of ARNG.

· Section 6 – Preliminary Conceptual Site Model: describes the pathways of potential PFAS

transport and receptors at the facility.

· Section 7 –Conclusions: summarizes the data findings and presents the conclusions and

uncertainties of the PA.

· Section 8 – References: provides the references used to develop this document.

· Appendix A – Data Resources

· Appendix B – Preliminary Assessment Documentation

· Appendix C – Photographic Log

1.4 Facility Location and Description

Fort Ruger lies on 325 acres that include an area in the interior of Diamond Head Crater and two

small administration annexes with a parking lot in Kahala to the east. The two annexes and

parking lot are located off Diamond Head Road. Fort Ruger proper is located on the east slopes

within the crater. The interior of the crater is also part of the Diamond Head State Monument.

The current Fort Ruger occupied by the Hawaiʻi ARNG (HIARNG) is a portion of the land originally

purchased and acquired by the US government in 1904-1906. The original lands were established

as the Fort Ruger Military Reservation (later shortened to “Fort Ruger”) and were occupied by the

US Army between 1909 to approximately 1955. In 1948, the US Army began transferring land to

the Territory of Hawaiʻi and gave verbal permission for the Hawaiʻi National Guard to occupy 10

acres of land. The agreement to transfer the Fort Ruger land to the Hawaiʻi National Guard was

not finalized until 1955, and portions of the land also went to other State of Hawaiʻi and federal

agencies. The buildings associated with Fort Ruger were built between 1942 and 1978. HIARNG

was home to the motor maintenance and regiment combat team from the 1950s until 2015. Fort

Ruger consisted of tunnels, above-ground offices, armories, and maintenance shops (Historic

American Buildings Survey, n.d; Appendix A). The buildings within the crater were demolished

in 2015. Figure 1-1 illustrates the location of Fort Ruger.
PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

5

1.5 Facility Environmental Setting

Fort Ruger is primarily located within the Diamond Head Crater, which is located on the southeast

extension of Oʻahu. Diamond Head is a tuff cone that was formed in one single volcanic event.

The highest point of the cone is at an elevation of 761 feet above mean sea level (amsl). Elevation

at Fort Ruger is approximately 200 feet amsl within the crater, and 90 feet amsl outside the crater

(US Geological Survey [USGS], 2017).

1.5.1 Geology

The topography at Fort Ruger is quite diverse. The area within the crater is relatively flat, with

sloping at the northern edge of the crater near the crater wall. Elevation along the crater wall

increases from 200 to 761 feet amsl. The soil consists of mostly weathered volcanic tuff, with

drainage ranging from very well drained to poorly drained, depending on the clay content. The

water table is approximately 200 feet below ground surface.

Diamond Head was formed during a period of volcanic activity known as the Honolulu Volcanic

Series, characterized by discrete, sporadic events that occurred long after the Waianae and

Koʻolau ranges were formed (AMEC, 2004). The geology of the crater consists of seven principal

rock formations, the oldest of which is Koʻolau Basalt, followed by a series of calcareous

sandstones, conglomerates, and calcareous aeolian sandstones, then by Kaimuki basalt,

Kupikopiko basalt, Kupikopiko black ash, modern alluvium and talus (Figure 1-2) (US Army

Center for Health Promotion and Preventative Medicine [USACPPH], 1998).

Based on the US Department of Agriculture (USDA), Natural Resources Conservation Service

(NRCS) Web Soil Survey, the facility is underlain by Makalapa clay and fill (USDA NRCS, 2014).

The Makalapa clay underlies the facility on the west and northwest half, and fill underlies the

facility’s southeast half. However, field observations for a 2004 AMEC comprehensive site

assessment suggested that the land classified by the USDA as fill was regraded Makalapa clay

(AMEC, 2014). Makalapa clay is characterized as having very slow permeability. The fill is

composed of marine and terrestrial sediments.

1.5.2 Hydrogeology

The aquifers below the subject parcel as part of Honolulu aquifer sector within the Pālolo and

Waiʻalae aquifer systems. The boundary between the two systems effectively bisects Diamond

Head crater from the northeast to the southwest, with the Pālolo system to the west, and the

Waiʻalae system to the east. The facility is above the Waiʻalae system. The groundwater system

beneath the Pālolo aquifer system consists of an upper and lower aquifer. The upper aquifer is

described as an unconfined basal type occurring in nonvolcanic, sedimentary lithology. This

aquifer is described as having potential use, though neither for drinking nor ecological utility. The

upper aquifer has moderate salinity (1,000-5,000 milligrams of chloride per liter (mg/L Cl-) of water,

and it is considered replaceable and highly vulnerable to contamination. The lower aquifer

beneath the Pālolo system is a confined basal aquifer occurring in flank lithology. This aquifer is

currently used for drinking water, is considered fresh (<250 mg/L Cl-), and highly vulnerable to

contamination.

The groundwater beneath the Waiʻalae aquifer system also consists of an upper and lower aquifer.

The upper aquifer is similar to the upper aquifer found in the Pālolo system, with the only

difference being in salinity (High, >5,000 mg/L Cl-). Likewise, the lower aquifer is similar to the

lower aquifer found in the Pālolo system. The Waiʻalae lower aquifer is not being used, though it

may potentially be tapped in the future (Mink and Lau, 1990).
PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

6

Fort Ruger is located oceanside of the Hawaiʻi Department of Health defined Underground

Injection Control (UIC) line. Areas above the UIC line denote potential underground drinking water

sources. Areas below the UIC line generally denote groundwater that is unsuitable for drinking

water purposes. Consequently, the groundwater below the subject parcel is considered a nondrinking water source.

An EDRTM report conducted a well search for a 1-mile radius surrounding the facility (Appendix

A). Using additional online resources, such as state and local Geographic Information System

databases, wells were researched to a 4-mile radius of the facility. Multiple domestic, industrial,

agricultural, irrigation, municipal water supply, and other wells are located upgradient or crossgradient to the facility. Only one well classified as “other” is located potentially downgradient from

the facility. Groundwater features are shown in Figure 1-2.

The USEPA Unregulated Contaminant Monitoring Rule 3 (UCMR3) data indicate that

PFOS/PFOA were not detected in a public water system above the USEPA HA within a 20-mile

radius of the facility. The HA is 70 parts per trillion for PFOS and PFOA, individually or combined.

PFAS analyses performed in 2016 had method detection limits that were higher than currently

achievable. Thus, it is possible that low concentrations of PFAS were not detected during the

UCMR3 but might be detected if analyzed today. PFAS analyses performed in 2016 had method

detection limits that were higher than currently achievable. Thus, it is possible that low

concentrations of PFAS were not detected during the UCMR3 but might be detected if analyzed

today.

1.5.3 Hydrology

No perennial streams exist on Fort Ruger. The crater rim walls prevent runoff from flowing through

the crater. Stormwater runoff within the crater follows the topography until it reaches openings

that enter into the City and County of Honolulu’s stormwater drainage system (Figure 1-3). The

City and County of Honolulu’s stormwater drainage system discharges untreated water into

natural waterways and the ocean (City and County of Honolulu, 2020).

1.5.4 Climate

Oʻahu is located in the tropics, with a climate characterized by mild temperatures, northeasterly

trade winds year-round, and moderate humidity. Hawaiʻi has two seasons: summer (between May

and October) and winter (between October and April). The average coastal temperature is

approximately 79 degrees Fahrenheit (°F), with temperatures decreasing at higher elevations.

The coldest temperatures are in January (72°F), and the warmest temperatures are in August

(89°F). Humidity on Oʻahu ranges from approximately 30 to 90 percent. Precipitation

predominantly occurs when the island’s mountain masses capture and cool the rising, warm,

moist ocean air, producing higher rainfall in the windward and mountain areas and lower rainfall

in the leeward and coastal zones. Annual rainfall ranges from 20 inches in the leeward coastal

areas to 250 inches on the Koʻolau mountain peaks (Macdonald, Abbott, and Peterson 1983).

Fort Ruger annual rainfall is 20 inches (National Oceanic and Atmospheric Administration, 2019).

1.5.5 Current and Future Land Use

There are currently no HIARNG operations occurring at Fort Ruger. The administration buildings

on the outside of the crater were transferred to private and state entities for other uses. Within the

crater, state and federal agencies such as Federal Aviation Administration, Diamond Head State

Monument, etc., have operations in the area. Buildings not in use were demolished. Due to the

location of Fort Ruger within the crater, it is reasonably anticipated future land use is not expected

to change from the current land use described above.
CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

ST

8/7/2020

8/7/2020

Preliminary Assessment for PFAS at Fort Ruger, HI

8/7/2020

1:63,360 ­ Figure 1-1 PM RG 8/7/2020

12420 Milestone Center Drive

Germantown, MD 20876

Facility Location

Base Map: Sources: Esri, HERE, Garmin, USGS,

Intermap, INCREMENT P, NRCan, Esri Japan, METI,

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\HI\Ft_Ruger_Figures\Fig_1-1_Ft_Ruger_Facility_Location.mxd

Fort Ruger

^_

0 0.5 1 2

Miles

Legend

Facility Boundary

7
A!

A!

A!

!5 !5

!5

A! A!

A!

A!

!5

!5

!5

!5!5

!5

A!

A!

A!A!

!C(

!C( !C(

!C(

!C(!C(

A!

!C(

!5

!5

AA!!!5

!5

!5

A! !5A! A!

!5!5

!C(

!C(!C(

!P!C(

!C(

!5! !C( 5

!5

!C(

A!

A! A!

AA!!

A! A!

!5 A! A! !C(

A!

!5

!5!5

A! A!

!5 !5A!!5

!5

!5 !C(!C(

!5

A!

A!

A!

!5

!5

!C(

!C(

!C(

!P

!C( !C(

A!

!C(

!5

!5!5!5

A!

AA!!A!

!C( !C( !C(

!5 !5

!C( !C(

!5

!P !5

!P

!C(

!C(!C(

&<

Waia‘lae Stre am

Mole kaStr e am

Waʻi

ōm aʻo Stre am

P ūk e le

Str ae m

P ālo lo Str eam

Kanahā Stre am

P auoaStre am

Mānoa

Stre am

CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

ST

8/10/2020

8/10/2020

P re lim inary As s e s s m e nt for P FAS at Fort Ruge r, HI

8/10/2020

1:95,040 ­ Figure 1-2 P M RG 8/10/2020

12420 Mile s tone Ce nte r Drive

Ge rm antown, MD 20876

Groundwater Features

Bas e Map: Sourc e : Es ri, Maxar, Ge oEye , Earths tar

Ge ographic s , CNES/Airb us DS, USDA, USGS,

C:\Us e rs \s tanke vic hm \One Drive - AECOM Dire c tory\ARNG_P FAS_GIS_60552172\MXDs \HI\Ft_Ruge r_Figure s \Fig_1-2_Ft_Ruge r_Ground wate r.m xd

Legend

Fac ility Bound ary

Wate r Bod y

We tland

Rive r/Stre am

Canal/Ditc h

Infe rre d Ground wate r Flow

Dire c tion

Geology

Manm ad e Fill

Be ac h De pos its

Alluvium

Old e r Alluvium

Old e r Dune De pos its

Lagoon and Re e f De pos its

Honolulu Volc anic s ;

Tantalus ve nt

Honolulu Volc anic s ,

Tantalus Flow; Lava Flows

Honolulu Volc anic s , Blac k

P oint and Kaim uki; Lava

Flows

Honolulu Volc anic s ,

Diam ond He ad ; Tuff

Honolulu Volc anic s ,

Kaim uki; Ve nt De pos its

Koolau Bas alts

Wells

!P Dom e s tic We ll

!5 Ind us trial We ll

!5 Agric ultural We ll

!5 Irrigation We ll

!C( Munic ipal Wate r Supply

We ll

A! Othe r We ll

0 0.75 1.5 3

Mile s

8
Ala Wai Canal-Frontal

Pacific Ocean Watershed

Waialae Nui Gulch-Frontal

Pacific Ocean Watershed

Mamala Bay-Pacific

Ocean Watershed

Wai‘alae S tre am

MānoaPalolo Drainag e Canal Pālolo S tre am

CLIENT

REVIS ED

S CALE

ARNG

GIS BY

CHK BY

MS

S T

8/7/2020

8/7/2020

Pre lim inary Asse ssm e nt for PFAS at Fort Rug e r, HI

8/7/2020

1:31,680 ­ Figure 1-3 PM RG 8/7/2020

12420 Mile stone Ce nte r Drive

Ge rm antown, MD 20876

Surface Water Features

Base Map: S ource : Esri, Maxar, Ge oEye , Earthstar

Ge og raphics, CNES /Airbus DS , US DA, US GS ,

C:\Use rs\stanke vichm \One Drive - AECOM Dire ctory\ARNG_PFAS _GIS _60552172\MXDs\HI\Ft_Rug e r_Fig ure s\Fig _1-3_Ft_Rug e r_S urface _Wate r.m xd

0 0.25 0.5 1

Mile s

Legend

Facility Bound ary

Wate r Bod y

We tland

Rive r/S tre am

S urface Wate r Flow

Dire ction

9
PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

10

2. Fire Training Areas

No FTAs were identified within the facility during the PA through interviews (Appendix B), EDRTM

reports (Appendix A), or from observations made during the VSI. The personnel interviewed had

institutional knowledge spanning from 1989 to present.
PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

11

3. Non-Fire Training Areas

In addition to FTAs, the PA evaluated areas where PFAS-containing materials may have been

broadly used, stored, or disposed. This may include buildings with fire suppression systems, paint

booths, AFFF storage areas, and areas of compliance demonstrations. Information on these

features obtained during the PA are included in Appendices A and B. Based on the interviewees’

knowledge of the facility, no non-FTAs are known or suspected at the facility. The personnel

interviewed had institutional knowledge spanning from 1989 to present. The maintenance

buildings were equipped with a water sprinkler system. AFFF is not currently or historically stored

at the facility; as such, no leaks or releases have been documented. The former maintenance

buildings were equipped with water systems prior to their demolishion. Photographs of the area

where the maintenance buildings once stood are included in the Photographic Log (Appendix

C).
PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

12

4. Emergency Response Areas

No instances of emergency response were identified at Fort Ruger during the PA based on

interviews, and online research. The facility has always relied on the local fire department for

emergency needs. There has been no need for response as of the date of the PA interviews

(Appendix B.1). The personnel interviewed had institutional knowledge spanning from 1989 to

present.
PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

13

5. Adjacent Sources

There were no off-facility sources of PFAS identified during the PA. The portion of Fort Ruger

within the interior of the Diamond Head Crater is also collocated with the Diamond Head State

Monument. Diamond Head State Monument is considered an adjacent property (not under ARNG

control) and has frequent brush fires due to the dry conditions within the crater. According to the

interviewee’s knowledge of the firefighting efforts, the fires are put out with water. No AFFF was

used to put the brush fires.
PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

14

6. Preliminary Conceptual Site Model

Based on the PA findings, no release areas were identified as areas of interest (AOIs); therefore, 

a preliminary conceptual site model (CSM) is not required for the facility. A CSM identifies three

components necessary for potentially complete exposure pathways: (1) source, (2) pathway, and

(3) receptor. If any of these elements are missing, the pathway is considered incomplete. Based

on the findings of this PA, there are no PFAS sources at Fort Ruger; thus, there is no complete

exposure pathway to potential receptors from ARNG use of the facility.
PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

15

7. Conclusions

This report presents a summary of available information gathered during the PA on the use and

storage of AFFF and other PFAS-related activities at Fort Ruger. The PA findings are based on

the information presented in Appendix A and Appendix B.

7.1 Findings

No AOIs related to PFAS releases to the environment were identified at Fort Ruger based on PA

data. Interviewees with knowledge dating back to 1989 confirmed that AFFF has never been used

or stored at Fort Ruger. The VSI also verified that AFFF is currently not stored at the facility, and

emergency fire suppression is provided by the municipal fire department. Figure 7-1 presents a

summary of the PA findings.

7.2 Uncertainties

A number of information sources were investigated during this PA to determine the potential for

PFAS-containing materials to have been present, used, or released at the facility. Historically,

documentation of PFAS use was not required because PFAS were considered benign. Therefore,

records were not typically kept by the facility or available during the PA on the use of PFAS in

training, firefighting, or other non-traditional activities, or on its disposition.

The conclusions of this PA are based on all available information, including: previous

environmental reports, EDRsTM, observations made during the VSI, and interviews. Interviews of

personnel with direct knowledge of a facility generally provided the most useful insights regarding

a facility's historical PFAS-containing materials. Gathered information has a degree of uncertainty

due to the absence of written documentation, the limited number of personnel with direct

knowledge due to staffing changes, the time passed since PFAS were first used (1969 to present),

and a reliance on personal recollection. Inaccuracies may arise in potential PFAS release

locations, dates of release, volume of releases, and the concentration of AFFF used. There is also

a possibility the PA has missed a source of PFAS, as the science of how PFAS may enter the

environment continually evolves.

In order to minimize the level of uncertainty, readily available data regarding the use and storage

of PFAS were reviewed, current personnel were interviewed, and potential source areas were

visually inspected.

The following table (Table 7-1) summarizes the uncertainties associated with the PA:

Table 7-1: Summary of Uncertainties

Location Source of Uncertainty

Fort Ruger During the interview process, a limited number of personnel were

available to be interviewed. Additionally, their tenure at the Fort Ruger

dates back to 1989. The use and storage of AFFF at Fort Ruger

between 1960 and 1989 are unknown.

Diamond Head

State Monument

(Adjacent Source)

The use and storage of AFFF at the Diamond Head State Monument

are unknown. No interviews were conducted for the adjacent area.
PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

16

7.3 Potential Future Actions

Based on the documented absence (1989 to present) of the use or release of PFAS-containing

materials at Fort Ruger, no AOIs were identified during the PA. Evidence does not indicate that

current or former ARNG activities contributed to PFAS contamination in soil, groundwater, surface

water, or sediment at the facility or adjacent areas. Fort Ruger will not move forward in the

CERCLA process.
Fort Ruger

CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

ST

9/10/2020

9/10/2020

Preliminary Assessment for PFAS at Fort Ruger, HI

9/10/2020

1:12,000 ­ Figure 7-1 PM RG 9/10/2020

12420 Milestone Center Drive

Germantown, MD 20876

Summary of Findings

Base Map: Source: Esri, Maxar, GeoEye, Earthstar

Geographics, CNES/Airbus DS, USDA, USGS,

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\HI\Ft_Ruger_Figures\Fig_7-1_Ft_Ruger_Summary.mxd

0 500 1,000 2,000

Feet

Legend

No Suspected Release

Facility Boundary

Water Body

Wetland

Diamond Head 

State Monument

17
PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

18

8. References

AMEC Earth and Environmental, Inc. (AMEC). 2004. Comprehensive Site Assessment/Remedial

Evaluation Report, Fort Ruger Firing Ranges, Diamond Head Crater, Honolulu, Hawaiʻi. March.

City and County of Honolulu. 2020. Storm Water Quality. Accessed online at

https://www.honolulu.gov/dfmswq.

Historic American Buildings Survey. n.d. Fort Ruger Military Reservation (Fort Ruger)

Photographs, Written Historical and Descriptive Data, Field Records. HABS No. HI-581.

Macdonald, G.A, A.T. Abbott, and F.L. Peterson. 1983. Volcanoes in the Sea: The Geology of

Hawaiʻi. 2nd ed. Honolulu, HI: University of Hawaiʻi Press

Mink, J. F., and L. S. Lau. 1990. Aquifer Identification and Classification for Oʻahu: Groundwater

Protection Strategy for Hawaiʻi. Technical Report No. 179. Honolulu: Univ. of Hawaiʻi, Water

Resources Research Center.

National Oceanic and Atmospheric Administration. 2019. Climate Data Online Database.

https://www.ncdc.noaa.gov/cdo-web/ (Accessed June 2019).

U.S. Army Center for Health Promotion and Preventative Medicine (USACHPPM). 1998. Phase I

Environmental Baseline Study No. 38-EH-7882-98, Hawaiʻi Army National Guard, Fort Ruger,

Honolulu, Hawaiʻi. July.

United States Department of Agriculture, Natural Resources Conservation Service (USDA

NRCS). 2014. Official Soil Series Descriptions. Accessed online at

http://www.nrcs.usda.gov/wps/portal/nrcs/main/soils/survey/class.

United States Environmental Protection Agency (USEPA). 1991. Guidance for Performing

Preliminary Assessments under CERCLA. EPA/540/G-91/013. September 1991

United State Geological Survey (USGS). 2017. USGS US Topo 7.5-minute map for Honolulu,

HI. September.
PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

Appendix A

Data Resources
PFAS Preliminary Assessment Report

Fort Ruger, O’ahu, Hawai’i

Data Resources will be provided separately on CD. Data Resources for Fort Ruger, Hawai’i 

include:

Fort Ruger EDRTM Report

• 2019 EDRTM Aerial Photo Decade Package

• 2019 EDRTM Radius Map Report with GeoCheck

• 2019 Certified Sanborn Map Report

Fort Ruger Historical Record

• Fort Ruger Military Reservation Historic American Buildings Survey, HABS No. HI-581

Fort Ruger Underground Injection Control Line

• UIC Line for Fort Ruger
PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

Appendix B

Preliminary Assessment Documentation
PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

Appendix B.1

Interview Records



PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

Appendix B.2

Visual Site Inspection Checklists




PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

Appendix B.3

Conceptual Site Model Information



PFAS Preliminary Assessment Report

Fort Ruger, Oʻahu, Hawaiʻi

Appendix C

Photographic Log
Preliminary Assessment Report

Fort Ruger

Perfluorooctane-Sulfonic Acid (PFOS) and 

Perfluorooctanoic Acid (PFOA) Impacted Sites

ARNG Installations, Nationwide

AECOM

APPENDIX C – Photographic Log

Army National Guard, Preliminary

Assessment for PFAS Fort Ruger Hawai’i

Photograph No. 1

Description:

Area where ARNG buildings 

once stood within Diamond 

Head Crater

Date Taken:

01 May 2019

Photograph No. 2

Description:

Area where ARNG buildings 

once stood within Diamond 

Head Crater.

Date Taken:

01 May 2019
Preliminary Assessment Report

Fort Ruger

Perfluorooctane-Sulfonic Acid (PFOS) and 

Perfluorooctanoic Acid (PFOA) Impacted Sites

ARNG Installations, Nationwide

AECOM

APPENDIX C – Photographic Log

Army National Guard, Preliminary

Assessment for PFAS Fort Ruger Hawai’i

Photograph No. 3

Description:

Area where ARNG buildings 

once stood within Diamond 

Head Crater.

Date Taken:

01 May 2019

Photograph No. 4

Description: 

Honolulu Fire Department 

firetruck stationed outside the 

facility fence line during the 

site visit.

Date Taken:

01 May 2019