&EPA
United States
Environmental Protection
Agency
Solid Waste And
Emergency Response
(OS-240)
EPA/540/8-91/019
September 1991
PB92-963216
National
Priorities
List Sites:
ARIZONA AND
NEVADA
Printed on Recycled Paper
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Publication #9200.5-704A
September 1991
NATIONAL PRIORITIES LIST SITES:
Arizona and Nevada
U.S. Environmental Protection Agency
Region 5, Library (PL-LU)
77 West Jackson Boulsvard, .- .
Chicago, IL 60604-3590
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Office of Emergency & Remedial Response
Office of Program Management
Washington, DC 20460
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If you wish to purchase copies of any additional State volumes contact:
National Technical Information Service (NTIS)
U.S. Department of Commerce
5285 Port Royal Road
Springfield, VA 22161
(703) 487-4650
The National Overview volume, Superfund: Focusing on the Nation at Large (1991),
may be ordered as PB92-963253.
The complete set of the overview documents, plus the 49 state reports may be ordered
as PB92-963253.
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TABLE OF CONTENTS
Page
Introduction:
A Brief Overview 1
Super fund:
How Does the Program Work to Clean Up Sites? 5
The Volume:
How to Use the State Book 13
NPL Sites:
In the State of Arizona 17
In the State of Nevada 19
The NPL Report:
Progress to Date 21
The NPL Fact Sheets:
Summary of Site Activities in Arizona 23
Summary of Site Activities in Nevada 47
Appendix A: Glossary:
Terms Used in the Fact Sheets 51
Appendix B: Repositories of
Site Information 57
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INTRODUCTION
WHY THE SUPERFUND
PROGRAM?
As the 1970s came to a close, a series of
headline stories gave Americans a
look at the dangers of dumping indus-
trial and urban wastes on the land. First there
was New York's Love Canal. Hazardous
waste buried there over a 25-year period
contaminated streams and soil, and endangered
the health of nearby residents. The result:
evacuation of several hundred people. Then
the leaking barrels at the Valley of the Drums
in Kentucky attracted public attention, as did
the dioxin-tainted land and water in Times
Beach, Missouri.
In all these cases, human health and the envi-
ronment were threatened, lives were disrupted,
and property values were reduced. It became
increasingly clear that there were large num-
bers of serious hazardous waste problems that
were falling through the cracks of existing
environmental laws. The magnitude of these
emerging problems moved Congress to enact
the Comprehensive Environmental Response,
Compensation, and Liability Act in 1980.
CERCLA commonly known as Superfund
was the first Federal law established to deal
with the dangers posed by the Nation's hazard-
ous waste sites.
After Discovery, the Problem
Intensified
Few realized the size of the problem until the
Environmental Protection Agency (EPA)
began the process of site discovery and site
evaluation. Not hundreds, but thousands of
potential hazardous waste sites existed, and
they presented the Nation with some of the
most complex pollution problems it had ever
faced.
Since the Superfund program began, hazard-
A
Brief
Overview
ous waste has surfaced as a major environ-
mental concern in every part of the United
States. It wasn't just the land that was con-
taminated by past disposal practices. Chemi-
cals in the soil were spreading into the ground-
water (a source of drinking water for many)
and into streams, lakes, bays, and wetlands.
Toxic vapors contaminated the air at some
sites, while improperly disposed or stored
wastes threatened the health of the surrounding
community and the environment at others.
The EPA Identified More than 1,200
Serious Sites
The EPA has identified 1,245 hazardous waste
sites as the most serious in the Nation. These
sites comprise the National Priorities List; sites
targeted for cleanup under Super-fund. But
site discoveries continue, and the EPA esti-
mates that, while some will be deleted after
lengthy cleanups, this list, commonly called
the NPL, will continue to grow by approxi-
mately 50 to 100 sites per year, potentially
reaching 2,100 sites by the year 2000.
THE NATIONAL CLEANUP
EFFORT IS MUCH MORE THAN
THE NPL
From the beginning of the program, Congress
recognized that the Federal government could
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INTRODUCTION
not and should not address all environmental
problems stemming from past disposal prac-
tices. Therefore, the EPA was directed to set
priorities and establish a list of sites to target.
Sites on the NPL (1,245) thus are a relatively
small subset of a larger inventory of potential
hazardous waste sites, but they do comprise
the most complex and compelling cases. The
EPA has logged more than 35,000 sites on its
national inventory of potentially hazardous
waste sites and assesses each site within one
year of being logged.
THE EPA IS MAKING PROGRESS
ON SITE CLEANUP
The goal of the Superfund program is to tackle
immediate dangers first and then move through
the progressive steps necessary to eliminate
any long-term risks to public health and the
environment.
Superfund responds immediately to sites
posing imminent threats to human health and
the environment at both NPL sites and sites not
on the NPL. The purpose is to stabilize,
prevent, or temper the effects of a release of
hazardous substances, or the threat of one, into
the environment. These might include tire
fires or transportation accidents involving the
spill of hazardous chemicals. Because they
reduce the threat a site poses to human health
and the environment, immediate cleanup
actions are an integral part of the Superfund
program.
Immediate response to imminent threats is one
of Superfund's most noted achievements.
Where imminent threats to the public or
environment were evident, the EPA has initi-
ated or completed emergency actions that
attacked the most serious threats of toxic
exposure in more than 2,700 cases.
The ultimate goal for a hazardous waste site on
the NPL is a permanent solution to an environ-
mental problem that presents a serious threat
to the public or the environment. This often
requires a long-term effort. The EPA has
aggressively accelerated its efforts to perform
these long-term cleanups of NPL sites. More
cleanups were started in 1987, when the
Superfund law was amended, than in any
previous year. By 1991, construction had
started at more than four times as many sites as
in 1986! Of the sites currently on the NPL,
more than 500 nearly half have had
construction cleanup activity. In addition,
more than 400 more sites presently are in the
investigation stage to determine the extent of
site contamination and to identify appropriate
cleanup remedies. Many other sites with
cleanup remedies selected are poised for the
start of cleanup construction activity. In
measuring success by "progress through the
cleanup pipeline," the EPA clearly is gaining
momentum.
THE EPA MAKES SURE
CLEANUP WORKS
The EPA has gained enough experience in
cleanup construction to understand that envi-
ronmental protection does not end when the
remedy is in place. Many complex technolo-
gies like those designed to clean up ground-
water must operate for many years in order
to accomplish their objectives.
The EPA's hazardous waste site managers are
committed to proper operation and mainte-
nance of every remedy constructed. No matter
who has been delegated responsibility for
monitoring the cleanup work, the EPA will
assure that the remedy is carefully followed
and that it continues to do its job.
Likewise, the EPA does not abandon a site
even after the cleanup work is done. Every
five years, the Agency reviews each site where
residues from hazardous waste cleanup still
remain to ensure that public and environmental
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INTRODUCTION
health are being safeguarded. The EPA will
correct any deficiencies discovered and will
report to the public annually on all five-year
reviews conducted that year.
CITIZENS HELP SHAPE
DECISIONS
Superfund activities also depend upon local
citizen participation. The EPA's job is to
analyze the hazards and to deploy the experts,
but the Agency needs citizen input as it makes
choices for affected communities.
Because the people in a community where a
Superfund site is located will be those most
directly affected by hazardous waste problems
and cleanup processes, the EPA encourages
citizens to get involved in cleanup decisions.
Public involvement and comment does influ-
ence EPA cleanup plans by providing valuable
information about site conditions, community
concerns, and preferences.
The State and U.S. Territories volumes and the
companion National overview volume provide
general Superfund background information
and descriptions of activities at each NPL site.
These volumes clearly describe what the
problems are, what the EPA and others partici-
pating in site cleanups are doing, and how we,
as a Nation, can move ahead in solving these
serious problems.
USING THE STATE AND
NATIONAL VOLUMES TOGETHER
To understand the big picture on hazardous
waste cleanup, citizens need to hear about both
environmental progress across the country and
the cleanup accomplishments closer to home.
Citizens also should understand the challenges
involved in hazardous waste cleanup and the
decisions we must make, as a Nation, in
finding the best solutions.
The National overview, Superfund: Focusing
on the Nation at Large (1991), contains impor-
tant information to help you understand the
magnitude and challenges facing the
Superfund program, as well as an overview of
the National cleanup effort. The sections
describe the nature of the hazardous waste
problem nationwide, threats and contaminants
at NPL sites and their potential effects on
human health and the environment, vital roles
of the various participants in the cleanup
process, the Superfund program's successes in
cleaning up the Nation's serious hazardous
waste sites, and the current status of the NPL.
If you did not receive this overview volume,
ordering information is provided in the front of
this book.
This volume compiles site summary fact sheets
on each State or Territorial site being cleaned
up under the Superfund program. These sites
represent the most serious hazardous waste
problems in the Nation and require the most
complicated and costly site solutions yet
encountered. Each book gives a "snapshot" of
the conditions and cleanup progress that has
been made at each NPL site. Information
presented for each site is current as of April
1991. Conditions change as our cleanup
efforts continue, so these site summaries will
be updated annually to include information on
new progress being made.
To help you understand the cleanup accom-
plishments made at these sites, this volume
includes a description of the process for site
discovery, threat evaluation, and long-term
cleanup of Superfund sites. This description,
How Does the Program Work to Clean Up
Sites?, will serve as a reference point from
which to review the cleanup status at specific
sites. A glossary defining key terms as they
apply to hazardous waste management and site
cleanup is included as Appendix A in the back
of this book.
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SUPERFUND
The diverse problems posed by hazard-
ous waste sites have provided the EPA
with the challenge to establish a consis-
tent approach for evaluating and cleaning up
the Nation's most serious sites. To do this, the
EPA has had to step beyond its traditional role
as a regulatory agency to develop processes
and guidelines for each step in these techni-
cally complex site cleanups. The EPA has
established procedures to coordinate the
efforts of its Washington, D.C. Headquarters
program offices and its front-line staff in ten
Regional Offices, with the State and local
governments, contractors, and private parties
who are participating in site cleanup. An
important part of the process is that any time
How Does the
Program Work
to Clean Up
Sites?
THREE-STEP SUPERFUND PROCESS
STEP1
Discover site and
determine whether
an emergency
exists *
STEP 2
Evaluate whether a
site is a serious threat
to public health or
environment
STEP 3
Perform long-term
cleanup actions on
the most serious
hazardous waste
sites in the Nation
* Emergency actions are performed whenever needed in this three-step process.
during cleanup, work can be led by the EPA
or the State or, under their monitoring, by
private parties who are potentially responsible
for site contamination.
The process for discovery of the site, evalu-
ation of threat, and the long-term cleanup of
Superfund sites is summarized in the follow-
ing pages. The phases of each of these steps
are highlighted within the description. The
flow diagram above provides a summary of the
three-step process.
Although this book provides a current "snap-
shot" of site progress made only by emergency
actions and long-term cleanup actions at
Superfund sites, it is important to understand
the discovery and evaluation process that leads
to identifying and cleaning up these most
serious uncontrolled or abandoned hazardous
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SUPERFUND.
waste sites in the Nation. The discovery and
evaluation process is the starting point for this
summary description of Superfund involve-
ment at hazardous waste sites.
STEP 1: SITE DISCOVERY AND
EMERGENCY EVALUATION
How does the EPA learn about
potential hazardous waste sites?
Site discovery occurs in a number of ways.
Information comes from concerned citizens.
People may notice an odd taste or foul odor in
their drinking water or see half-buried leaking
barrels; a hunter may come across a field
where waste was dumped illegally. There may
be an explosion or fire, which alerts the State
or local authorities to a problem. Routine
investigations by State and local governments
and required reporting and inspection of
facilities that generate, treat, store, or dispose
of hazardous waste also help keep the EPA
informed about actual or potential threats of
hazardous substance releases. All reported
sites or spills are recorded in the Superfund
inventory (CERCLIS) for further investigation
to determine whether they will require cleanup.
What happens If there is an imminent
danger?
As soon as a potential hazardous waste site is
reported, the EPA determines whether there is
an emergency requiring an immediate cleanup
action. If there is, they act as quickly as
possible to remove or stabilize the imminent
threat. These short-term emergency actions
range from building a fence around the con-
taminated area to keep people away, or tempo-
rarily relocating residents until the danger is
addressed, to providing bottled water to resi-
dents while their local drinking water supply is
being cleaned up or physically removing
wastes for safe disposal.
However, emergency actions can happen at
any time an imminent threat or emergency
warrants them. For example, if leaking barrels
are found when cleanup crews start digging in
the ground or if samples of contaminated soils
or air show that there may be a threat of fire or
explosion, an immediate action is taken.
STEP 2: SITE THREAT EVALUATION
If there Isn't an imminent danger, how
does the EPA determine what, if any,
cleanup actions should be taken?
Even after any imminent dangers are taken
care of, in most cases, contamination may
remain at the site. For example, residents may
have been supplied with bottled water to take
care of their immediate problem of contami-
nated well water, but now it's time to deter-
mine what is contaminating the drinking water
supply and the best way to clean it up. The
EPA may determine that there is no imminent
danger from a site, so any long-term threats
need to be evaluated. In either case, a more
comprehensive investigation is needed to
determine if a site poses a serious, but not
imminent, danger and whether it requires a
long-term cleanup action.
Once a site is discovered and any needed
emergency actions are taken, the EPA or the
State collects all available background infor-
mation not only from their own files, but also
from local records and U.S. Geological Survey
maps. This information is used to identify the
site and to perform a preliminary assessment of
its potential hazards. This is a quick review of
readily available information to answer the
questions:
Are hazardous substances likely to be
present?
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SUPERFUND
How are they contained?
How might contaminants spread?
How close is the nearest well, home, or
natural resource area such as a wetland
or animal sanctuary?
What may be harmed the land,
water, air, people, plants, or animals?
Some sites do not require further action be-
cause the preliminary assessment shows that
they do not threaten public health or the envi-
ronment. But even in these cases, the sites
remain listed in the Superfund inventory for
record-keeping purposes and future reference.
Currently, there are more than 35,000 sites
maintained in this inventory.
If the preliminary assessment
shows a serious threat may exist,
what's the next step?
Inspectors go to the site to collect additional
information to evaluate its hazard potential.
During this site inspection, they look for
evidence of hazardous waste, such as leaking
drums and dead or discolored vegetation.
They may take some samples of soil, well
water, river water, and air. Inspectors analyze
the ways hazardous materials could be pollut-
ing the environment, such as runoff into
nearby streams. They also check to see if
people (especially children) have access to
the site.
How does the EPA use the results of
the site inspection?
Information collected during the site inspection
is used to identify the sites posing the most
serious threats to human health and the envi-
ronment. This way, the EPA can meet the
requirement that Congress gave them to use
Superfund monies only on the worst hazardous
waste sites in the Nation.
To identify the most serious sites, the EPA
developed the Hazard Ranking System (HRS).
The HRS is the scoring system the EPA uses to
assess the relative threat from a release or a
potential release of hazardous substances from
a site to surrounding groundwater, surface
water, air, and soil. A site score is based on
the likelihood that a hazardous substance will
be released from the site, the toxicity and
amount of hazardous substances at the site, and
the people and sensitive environments poten-
tially affected by contamination at the site.
Only sites with high enough health and envi-
ronmental risk scores are proposed to be added
to the NPL. That's why 1,245 sites are on the
NPL, but there are more than 35,000 sites in
the Superfund inventory. Only NPL sites can
have a long-term cleanup paid for from
Superfund, the national hazardous waste trust
fund. Superfund can, and does, pay for emer-
gency actions performed at any site, whether
or not it's on the NPL.
Why are sites proposed to the NPL?
Sites proposed to the NPL have been evaluated
through the scoring process as the most serious
problems among uncontrolled or abandoned
hazardous waste sites in the U.S. In addition, a
site will be proposed to the NPL if the Agency
for Toxic Substances and Disease Registry
issues a health advisory recommending that
people be moved away from the site. The NPL
is updated at least once a year, and it's only
after public comments are considered that
these proposed worst sites officially are added
to the list.
Listing on the NPL does not set the order in
which sites will be cleaned up. The order is
influenced by the relative priority of the site's
health and environmental threats compared to
other sites, and such factors as State priorities,
engineering capabilities, and available tech-
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SUPERFUND.
nologies. Many States also have their own list
of sites that require cleanup; these often contain
sites that are not on the NPL and are scheduled
to be cleaned up with State money. And, it
should be noted again that any emergency
action needed at a site can be performed by the
Superfund, whether or not a site is on the NPL.
A detailed description of the current progress in
cleaning up NPL sites is found in the section of
the 1991 National overview volume entitled
Cleanup Successes: Measuring Progress.
How do people find out whether the
EPA considers a site a national
priority for cleanup under the
Superfund Program?
All NPL sites, where Superfund is responsible
for cleanup, are described in the State and
Territorial volumes. The public also can find
out whether other sites, not on the NPL, are
being addressed by the Superfund program by
calling their Regional EPA office or the Super-
fund Hotline at the numbers listed in this book.
STEP 3: LONG-TERM CLEANUP
ACTIONS
After a site is added to the NPL, what
are the steps to cleanup?
The ultimate goal for a hazardous waste site on
the NPL is a permanent, long-term cleanup.
Since every site presents a unique set of chal-
lenges, there is no single all-purpose solution.
A five-phase "remedial response" process is
used to develop consistent and workable
solutions to hazardous waste problems across
the Nation:
1. Remedial Investigation: investigate in
detail the extent of the site contamination
2. Feasibility Study: study the range of
possible cleanup remedies
3. Record of Decision or ROD: decide
which remedy to use
4. Remedial Design: plan the remedy
5. Remedial Action: carry out the remedy
This remedial response process is a long-term
effort to provide a permanent solution to an
environmental problem that presents a serious
threat to the public or environment.
The first two phases of a long-term cleanup are
a combined remedial investigation and feasibil-
ity study (RI/FS) that determine the nature and
extent of contamination at the site and identify
and evaluate cleanup alternatives. These
studies may be conducted by the EPA or the
State or, under their monitoring, by private
parties.
Like the initial site inspection described earlier,
a remedial investigation involves an examina-
tion of site data in order to better define the
problem. However, the remedial investigation
is much more detailed and comprehensive than
the initial site inspection.
A remedial investigation can best be described
as a carefully designed field study. It includes
extensive sampling and laboratory analyses to
generate more precise data on the types and
quantities of wastes present at the site, the type
of soil and water drainage patterns, and specific
human health and environmental risks.
The result of the remedial investigation is
information that allows the EPA to select the
cleanup strategy that is best suited to a particu-
lar site or to determine that no cleanup is
needed.
Placing a site on the NPL does not necessarily
mean that cleanup is needed. It is possible for
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SUPERFUND
a site to receive an MRS score high enough to
be added to the NPL, but not ultimately require
cleanup actions. Keep in mind that the purpose
of the scoring process is to provide a prelimi-
nary and conservative assessment of potential
risk. During subsequent site investigations, the
EPA may find either that there is no real threat
or that the site does not pose significant human
health or environmental risks.
How are cleanup alternatives
identified and evaluated?
The EPA or the State or, under their monitor-
ing, private parties identify and analyze spe-
cific site cleanup needs based on the extensive
information collected during the remedial
investigation. This analysis of cleanup alterna-
tives is called a feasibility study.
Since cleanup actions must be tailored exactly
to the needs of each individual site, more than
one possible cleanup alternative is always
considered. After making sure that all potential
cleanup remedies fully protect human health
and the environment and comply with Federal
and State laws, the advantages and disadvan-
tages of each cleanup alternative are compared
carefully. These comparisons are made to
determine their effectiveness in the short and
long term, their use of permanent treatment
solutions, and their technical feasibility and
cost.
To the maximum extent practicable, the rem-
edy must be a permanent solution and must use
treatment technologies to destroy principal site
contaminants. Remedies such as containing the
waste on site or removing the source of the
problem (like leaking barrels) often are consid-
ered effective. Often, special pilot studies are
conducted to determine the effectiveness and
feasibility of using a particular technology to
clean up a site. Therefore, the combined
remedial investigation and feasibility study can
take between 10 and 30 months to complete,
depending on the size and complexity of the
problem.
Does the public have a say in the
final cleanup decision?
Yes. The Superfund law requires that the
public be given the opportunity to comment on
the proposed cleanup plan. Their concerns are
considered carefully before a final decision is
made.
The results of the remedial investigation and
feasibility study, which also point out the
recommended cleanup choice, are published in
a report for public review and comment. The
EPA or the State encourages the public to
review the information and take an active role
in the final cleanup decision. Fact sheets and
announcements in local papers let the commu-
nity know where they can get copies of the
study and other reference documents concern-
ing the site. Local information repositories,
such as libraries or other public buildings, are
established in cities and towns near each NPL
site to ensure that the public has an opportunity
to review all relevant information and the
proposed cleanup plans. Locations of informa-
tion repositories for each NPL site described in
this volume are given in Appendix B.
The public has a minimum of 30 days to
comment on the proposed cleanup plan after it
is published. These comments can be written
or given verbally at public meetings that the
EPA or the State are required to hold. Neither
the EPA nor the State can select the final
cleanup remedy without evaluating and provid-
ing written answers to specific community
comments and concerns. This "responsiveness
summary" is part of the EPA's write-up of the
final remedy decision, called the Record of
Decision, or ROD.
The ROD is a public document that explains
the cleanup remedy chosen and the reason it
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SUPERFUND.
was selected. Since sites frequently are large
and must be cleaned up in stages, a ROD may
be necessary for each contaminated resource or
area of the site. This may be necessary when
contaminants have spread into the soil, water,
and air and affect such sensitive areas as
wetlands, or when the site is large and cleaned
up in stages. This often means that a number
of remedies, using different cleanup technolo-
gies, are needed to clean up a single site.
If every cleanup action needs to be
tailored to a site, does the design
ofthe remedy need to be tailored,
too?
Yes. Before a specific cleanup action is carried
out, it must be designed in detail to meet
specific site needs. This stage of the cleanup is
called the remedial design. The design phase
provides the details on how the selected rem-
edy will be engineered and constructed.
Projects to clean up a hazardous waste site may
appear to be like any other major construction
project but, in fact, the likely presence of
combinations of dangerous chemicals demands
special construction planning and procedures.
Therefore, the design of the remedy can take
anywhere from six months to two years to
complete. This blueprint for site cleanup
includes not only the details on every aspect of
the construction work, but a description of the
types of hazardous wastes expected at the site,
special plans for environmental protection,
worker safety, regulatory compliance, and
equipment decontamination.
Once the design is completed,
how long does it take to actually
clean up the site, and how much
does it cost?
The time and cost for performing the site
cleanup, called the remedial action, are as
varied as the remedies themselves. In a few
cases, the only action needed may be to remove
drums of hazardous waste and to decontami-
nate them, an action that takes limited time and
money. In most cases, however, a remedial
action may involve different and expensive
cleanup measures that can take a long time.
For example, cleaning polluted groundwater or
dredging contaminated river bottoms can take
several years of complex engineering work
before contamination is reduced to safe levels.
Sometimes the selected cleanup remedy de-
scribed in the ROD may need to be modified
because of new contaminant information
discovered or difficulties that were faced
during the early cleanup activities. Taking into
account these differences, each remedial
cleanup action takes an average of 18 months
to complete and ultimately costs an average of
$26 million to complete all necessary cleanup
actions at a site.
Once the cleanup action is
completed, is the site
automatically "deleted" from the
NPL?
No. The deletion of a site from the NPL is
anything but automatic. For example, cleanup
of contaminated groundwater may take up to
20 years or longer. Also, in some cases, long-
term monitoring of the remedy is required to
ensure that it is effective. After construction of
certain remedies, operation and maintenance
(e.g., maintenance of ground cover, groundwa-
ter monitoring, etc.), or continued pumping and
treating of groundwater may be required to
ensure that the remedy continues to prevent
future health hazards or environmental damage
and ultimately meets the cleanup goals speci-
fied in the ROD. Sites in this final monitoring
or operational stage of the cleanup process are
designated as "construction complete."
It's not until a site cleanup meets all the goals
and monitoring requirements of the selected
10
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SUPERFUND
remedy that the EPA can officially propose the
site for deletion from the NPL, and it's not
until public comments are taken into consid-
eration that a site actually can be deleted from
the NPL. All sites deleted from the NPL and
sites with completed construction are included
in the progress report found later in this book.
Can a site be taken off the NPL if
no cleanup has taken place?
Yes. But only if further site investigation
reveals that there are no threats present at the
site and that cleanup activities are not neces-
sary. In these cases, the EPA will select a "no
action" remedy and may move to delete the
site when monitoring confirms that the site
does not pose a threat to human health or the
environment.
In other cases, sites may be "removed" from
the NPL if new information concerning site
cleanup or threats show that the site does not
warrant Superfund activities.
A site may be removed if a revised HRS
scoring, based on updated information, results
in a score below the minimum for NPL sites.
A site also may be removed from the NPL by
transferring it to other appropriate Federal
cleanup authorities, such as RCRA, for further
cleanup actions.
Removing sites for technical reasons or trans-
ferring sites to other cleanup programs pre-
serves Superfund monies for the Nation's most
pressing hazardous waste problems where no
other cleanup authority is applicable.
Can the EPA make parties
responsible for the contamination
pay?
Yes. Based on the belief that "the polluters
should pay," after a site is placed on the NPL,
the EPA makes a thorough effort to identify
and find those responsible for causing con-
tamination problems at a site. Although the
EPA is willing to negotiate with these private
parties and encourages voluntary cleanup, it
has the authority under the Superfund law to
legally force those potentially responsible for
site hazards to take specific cleanup actions.
All work performed by these parties is closely
guided and monitored by the EPA and must
meet the same standards required for actions
financed through the Superfund.
Because these enforcement actions can be
lengthy, the EPA may decide to use Superfund
monies to make sure a site is cleaned up
without unnecessary delay. For example, if a
site presents an imminent threat to public
health and the environment or if conditions at a
site may worsen, it could be necessary to start
the cleanup right away. Those responsible for
causing site contamination are liable under the
law (CERCLA) for repaying the money the
EPA spends in cleaning up the site.
Whenever possible, the EPA and the Depart-
ment of Justice use their legal enforcement
authorities to require responsible parties to pay
for site cleanups, thereby preserving Superfund
resources for emergency actions and for sites
where no responsible parties can be identified.
11
-------
THE VOLUME
The site fact sheets presented in this
book are comprehensive summaries
that cover a broad range of information.
The fact sheets describe hazardous
waste sites on the NPL and their locations, as
well as the conditions leading to their listing
("Site Description"). The summaries list the
types of contaminants that have been discov-
ered and related threats to public and ecologi-
cal health ("Threats and Contaminants").
"Cleanup Approach" presents an overview of
the cleanup activities completed, underway, or
planned. The fact sheets conclude with a brief
synopsis of how much progress has been made
in protecting public health and the environ-
ment. The summaries also pinpoint other
actions, such as legal efforts to involve pollut-
ers responsible for site contamination and
community concerns.
The fact sheets are arranged in alphabetical
order by site name. Because site cleanup is a
dynamic and gradual process, all site informa-
tion is accurate as of the date shown on the
bottom of each page. Progress always is being
made at NPL sites, and the EPA periodically
will update the site fact sheets to reflect recent
actions and will publish updated State vol-
umes. The following two pages show a ge-
neric fact sheet and briefly describe the infor-
mation under each section.
HOW CAN YOU USE THIS STATE
BOOK?
You can use this book to keep informed about
the sites that concern you, particularly ones
close to home. The EPA is committed to
involving the public in the decision making
process associated with hazardous waste
cleanup. The Agency solicits input from area
residents in communities affected by Super-
fund sites. Citizens are likely to be affected
not only by hazardous site conditions, but also
by the remedies that combat them. Site clean-
How to Use
the State
Book
ups take many forms and can affect communi-
ties in different ways. Local traffic may be
rerouted, residents may be relocated, tempo-
rary water supplies may be necessary.
Definitive information on a site can help
citizens sift through alternatives and make
decisions. To make good choices, you must
know what the threats are and how the EPA
intends to clean up the site. You must under-
stand the cleanup alternatives being proposed
for site cleanup and how residents may be
affected by each one. You also need to have
some idea of how your community intends to
use the site in the future, and you need to
know what the community can realistically
expect once the cleanup is complete.
The EPA wants to develop cleanup methods
that meet community needs, but the Agency
only can take local concerns into account if it
understands what they are. Information must
travel both ways in order for cleanups to be
effective and satisfactory. Please take this
opportunity to learn more, become involved,
and assure that hazardous waste cleanup at
"your" site considers your community's
concerns.
13
-------
THE VOLUME
NPL LISTING HISTORY
Dates when the site was
Proposed, made Final, and
Deleted from the NPL.
SITE RESPONSIBILITY
Identifies the Federal, State,
and/or potentially respon-
sible parties that are taking
responsibility for cleanup
actions at the site.
SITE NAME
STATE
EPA ID* ABCOOOOOOO
^Sit^Descrlptlon
EPA REGION XX
CONGRESSIONAL DIST XX
COUNTY NAME
LOCATION
Other Name*:
NPL Listing History
Proposed:
Flimb
reats and Contaminants
Cleanup Approach
Response Action Status
©
Site Facts: P.
Environmental Progress
ENVIRONMENTAL PROGRESS
A summary of the actions to reduce the threats to
nearby residents and the surrounding environment;
progress towards cleaning up the site and goals of
the cleanup plan are given here.
14
-------
THE VOLUME
SITE DESCRIPTION
This section describes the location and history of the site. It includes descrip-
tions of the most recent activities and past actions at the site that have con-
tributed to the contamination. Population estimates, land usages, and nearby
resources give readers background on the local setting surrounding the site.
THREATS AND CONTAMINANTS
The major chemical categories of site contamination are noted, as well as
which environmental resources are affected. Icons representing each of the
affected resources (may include air, groundwater, surface water, soil, and
contamination to environmentally sensitive areas) are included in the margins
of this section. Potential threats to residents and the surrounding environ-
ments arising from the site contamination also are described.
CLEANUP APPROACH
This section contains a brief overview of how the site is being cleaned up.
RESPONSE ACTION STATUS
Specific actions that have been accomplished or will be undertaken to clean
up the site are described here. Cleanup activities at NPL sites are divided
into separate phases, depending on the complexity and required actions at the
site. Two major types of cleanup activities often are described: initial,
immediate, or emergency actions to quickly remove or reduce imminent
threats to the community and surrounding areas; and long-term remedial
phases directed at final cleanup at the site. Each stage of the cleanup strategy
is presented in this section of the summary. Icons representing the stage of
the cleanup process (initial actions, site investigations, EPA selection of the
cleanup remedy, engineering design phase, cleanup activities underway, and
completed cleanup) are located in the margin next to each activity descrip-
tion.
SITE FACTS
Additional information on activities and events at the site are included in this
section. Often details on legal or administrative actions taken by the EPA to
achieve site cleanup or other facts pertaining to community involvement with
the site cleanup process are reported here.
15
-------
THE VOLUME
The "icons," or symbols, accompanying the text allow the reader to see at a glance which envi-
ronmental resources are affected and the status of cleanup activities at the site.
Icons in the Threats and
Contaminants Section
Contaminated Groundwater resources
in the Contaminated Groundwater in
the vicinity or underlying the site.
(Groundwater is often used as a
drinking water source.)
Contaminated Surface Water and
Sediments on or near the site. (These
include lakes, ponds, streams, and
rivers.)
Contaminated Air in the vicinity of
the site. (Air pollution usually is
periodic and involves contaminated
dust particles or hazardous gas emis-
sions.)
Contaminated Soil and Sludges on or
near the site. (This contamination
category may include bulk or other
surface hazardous wastes found on the
site.)
Threatened or contaminated Environ-
mentally Sensitive Areas in the vicin-
ity of the site. (Examples include
wetlands and coastal areas or critical
habitats.)
Icons in the Response Action
Status Section
Initial Actions have been taken or are
underway to eliminate immediate
threats at the site.
Site Studies at the site to determine the
nature and extent of contamination are
planned or underway.
Remedy Selected indicates that site
investigations have been concluded,
and the EPA has selected a final
cleanup remedy for the site or part of
the site.
Remedy Design means that engineers
are preparing specifications and
drawings for the selected cleanup
technologies.
Cleanup Ongoing indicates that the
selected cleanup remedies for the
contaminated site, or part of the site,
currently are underway.
Cleanup Complete shows that all
cleanup goals have been achieved for
the contaminated site or part of the
site.
Environmental Progress summa-
rizes the activities taken to date to
protect human health and to clean
up site contamination.
16
-------
NPL SITES
The State of
Arizona
The State of Arizona is located in the southwestern United States, within EPA Region 9. Region
9 includes the states situated in the southwestern U.S. and Hawaii. Arizona covers 114,000
square miles consisting of the Colorado plateau, including the Grand Canyon, the Mexican
Highlands, and the Sonoran Desert. According to the U.S. Census, the state experienced a 35%
increase in population between 1980 and 1990 and currently has approximately 3,489,000
residents, ranking 24th in U.S. populations. Principal State industries include manufacturing,
tourism, mining, and agriculture. Arizona firms manufacture electronics, printing and publish-
ing, foods, primary and fabricated metals, aircraft and missiles, and apparel.
How Many NPL Sites
Are in the State of Arizona?
Proposed
Final
Deleted
0
10
_L
11
Where Are the NPL Sites Located?
Congressional District 1
Congressional District 2
Congressional District 3
Congressional District 4
2 sites
4 sites
3 sites
2 sites
What Type of Sites Are on the NPL
in the State of Arizona?
# of sites
3
2
2
1
1
2
type of sites
Federal Facilities
Municipal & Industrial Landfills
Electronics & Electrical Equipment
Chemicals & Allied Products
Asbestos
Other (Aircraft, Mixed)
17
April 1991
-------
NPL SITES
How Are Sites Contaminated and What Are the Principal* Chemicals?
10--
8
6-
4 --
2 --
Soil GW SW Air
Contamination Area
Soil, Solid and Liquid Wastes:
Volatile organic compounds (VOCs)
and heavy metals (inorganics).
Groundwater: Volatile organic
compounds (VOCs) and heavy metals
(inorganics).
Surface Water: Heavy metals
(inorganics), volatile organic com-
pounds (VOCs), and radiation.
Air: Volatile organic compounds
(VOCs) and asbestos.
'Appear at 25% or more sites
Where Are the Sites in the Superfund Cleanup Process?1
4
Sites
with I
Studies
Underway
Sites
with
Remedy
Selected
2
Sites
with
Remedy
Design
3
Sites
with
Cleanup
Ongoing
Sites
with
Construction
Complete
Deleted
Site
In addition to the activities described above, initial actions have been taken at 7 sites as interim
cleanup measures.
'Cleanup status reflects phases of site activities rather than administrative accomplishments.
ApriM991
18
-------
.NPL SITES
The State of
Nevada
The State of Nevada is located in Region 9, which includes the states situated in the southwest-
ern U.S. and Hawaii. The state covers 110,561 square miles, consisting mostly of the Mojave
Desert in the southwest and the Rocky Mountains in the northeast Ranked 39th in U.S. popula-
tions, according to the 1990 Census, Nevada experienced a 50% increase in population between
1980 and 1990 and currently has approximately 1,202,000 residents. Principal state industries
include gaming, tourism, mining, manufacturing, government, agriculture, warehousing, and
trucking. Goods manufactured in Nevada include gaming devices, electronics, chemicals, and
stone-clay-glass products.
How Many NPL Sites
Are in the State of Nevada?
Proposed
Final
Deleted
0
1
Q
1
Where Are the NPL Sites Located?
Congressional District 1
1 site
What Type of Sites Are on the NPL
in the State of Nevada?
# of sites
type of site
Mining
19
April 1991
-------
NPL SITES
How Are Sites Contaminated and What Are the Principal* Chemicals?
7-r
M
fl>
.«
M
3 --
GW Soil SW Sed
Contamination Area
Groundwater: Heavy metals
(mercury and inorganics).
Surface Water: Heavy metals
(mercury and inorganics).
Soil: Heavy metals (mercury and
inorganics).
Where Are the Sites in the Superfund Cleanup Process?*
i
Site
with I
Studies
Underway
Sites
with
Remedy
Selected
Sites
with
Remedy
Design
Sites
with
Cleanup
Ongoing
Site
with
Construction
Complete
Deleted
Sites
In addition to the activities described above, initial actions have been taken at 1 site as interim
cleanup measures.
'Cleanup status reflects phases of site activities rather than administrative accomplishments.
April 1991
20
-------
THE NPL REPORT
The following Progress Report lists all
sites currently on, or deleted from, the
NPL and briefly summarizes the status
of activities for each site at the time this
report was prepared. The steps in the Super-
fund cleanup process are arrayed across the
top of the chart, and each site's progress
through these steps is represented by an arrow
(O-) indicating the current stage of cleanup.
Large and complex sites often are organized
into several cleanup stages. For example,
separate cleanup efforts may be required to
address the source of the contamination,
hazardous substances in the groundwater, and
surface water pollution, or to clean up differ-
ent areas of a large site. In such cases, the
chart portrays cleanup progress at the site's
most advanced stage, reflecting the status of
site activities rather than administrative
accomplishments.
An arrow in the "Initial Response" cate-
gory indicates that an emergency cleanup or
initial action has been completed or currently
is underway. Emergency or initial actions are
taken as an interim measure to provide im-
mediate relief from exposure to hazardous site
conditions or to stabilize a site to prevent
further contamination.
A final arrow in the "Site Studies"
category indicates that an investigation to
determine the nature and extent of the
contamination at the site currently is ongoing.
A final arrow in the "Remedy Selection"
category means that the EPA has selected the
final cleanup strategy for the site. At the few
sites where the EPA has determined that
initial response actions have eliminated site
contamination, or that any remaining
contamination will be naturally dispersed
without further cleanup activities, a "No
Progress
To Date
Action" remedy is selected. In these cases, the
arrows are discontinued at the "Remedy
Selection" step and resume in the
"Construction Complete" category.
A final arrow at the "Remedial Design"
stage indicates that engineers currently are
designing the technical specifications for the
selected cleanup remedies and technologies.
A final arrow in the "Cleanup Ongoing"
column means that final cleanup actions have
been started at the site and currently are
underway.
A final arrow in the "Construction
Complete" category is used only when all
phases of the site cleanup plan have been
performed, and the EPA has determined that no
additional construction actions are required at
the site. Some sites in this category currently
may be undergoing long-term operation and
maintenance or monitoring to ensure that the
cleanup actions continue to protect human
health and the environment.
A check in the "Deleted" category indicates
that the site cleanup has met all human health
and environmental goals and that the EPA has
deleted the site from the NPL.
Further information on the activities and
progress at each site is given in the site "Fact
Sheets" published in this volume.
21
April 1991
-------
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22
-------
THE NPL FACT SHEETS
Summary
of Site
Activities
EPA REGION 9
23
April!991
-------
Who Do I Call with Questions?
The following pages describe each NPL site in Arizona, providing specific
information on threats and contaminants, cleanup activities, and environmen-
tal progress. Should you have questions, please call the EPA's Region 9
Office in San Francisco, California or one of the other offices listed below:
EPA Region 9 Superfund Community Relations Office
EPA Region 9 Superfund Office
EPA Superfund Hotline
EPA Headquarters Public Information Center
Arizona Superfund Office
(415) 744-2175
(415) 744-2356
(800) 424-9346
(202) 260-2080
(602) 257-2215
April! 991
24
-------
APACHE POWDER"
COMPANY
ARIZONA
EPA ID* AZD008399263
Site Description
EPA REGION 9
CONGRESSIONAL DIST. 02
Cochise County
St. David
Other Names:
Apache Nitrogen Products, Inc.
The Apache Powder Company has manufactured explosives and fertilizers on this 945-acre site
since 1922. Prior to 1971, all wastewater was disposed of by flushing it into dry washes; the water
then soaked into the ground or flowed into the San Pedro River. Since 1971, the company has been
storing the wastewater in holding ponds. The water in these holding ponds contains high levels of
nitrates, and the ponds may have leaked nitrates into the groundwater. In 1980, the EPA found high
levels of heavy metals in one of the ponds. Ten shallow wells downgradient from the facility were
found to contain nitrates. Approximately 1,100 people depend on wells for drinking water within 3
miles of the site. The nearest residence is less than 1/4 mile from the facility. Alfalfa is grown
commercially within the vicinity of the site and is used as feed for cattle. Elevated levels of nitrates
have been detected in the San Pedro River, which borders the site.
Site Responsibility:
This site is being addressed through
Federal and potentially responsible
parties' actions.
NPL LISTING HISTORY
Proposed Date: 06/10/86
Final Date: 08/30/90
Threats and Contaminants
l\
Groundwater and surface water contain nitrates, nitrites, and strontium. Soil and
holding pond sludge contain nitrates, nitrites, lead, chromium, zinc, and strontium.
People who ingest contaminated groundwater, surface water, soil, or sludges may be
at risk. Wildlife in or around the San Pedro River may be harmed by contaminants
leaking into the river.
Cleanup Approach
This site is being addressed in two stages: immediate actions and a long-term remedial phase
focusing on cleanup of the entire site.
25
April!991
-------
Response Action Status
Immediate Actions: In 1987, as a result of earlier water quality testing by the EPA, the
Apache Powder Company began providing bottled water to area residents whose well
water was found to be contaminated.
Entire Site: An investigation to determine the type and extent of contamination at the
site is being conducted by the Apache Powder Company. Once the investigation is
completed in 1992, measures will be recommended for site cleanup. This investigation
will include a study of the surface water pattern and sources, the location and hydrology of
groundwater aquifers, and background levels of various chemicals and metals.
Site Facts: In 1989, the Apache Powder Company entered into an Administrative Order, requiring
Apache to conduct an investigation of site contamination and into the potential for public health and
environmental threats.
Environmental Progress
The immediate action described above has provided a safe drinking water supply to affected
residents and has eliminated the potential of exposure to contaminated drinking water. This initial
action will continue to protect residents near the Apache Powder Company site until planned cleanup
activities are completed.
April 1991 26 APACHE POWDER COMPANY
-------
HASSAYAMPA
LANDFILL
ARIZONA
EPAID#AZD980735666
EPA REGION 9
CONGRESSIONAL DIST. 03
Maricopa County
40 miles west of Phoenix
Site Description
The 77-acre Hassayampa Landfill site has been used as a municipal landfill since 1961 and
accepted approximately 3,000,000 gallons of liquid and 4,000 tons of solid hazardous waste.
The hazardous wastes were deposited in unlined trenches from 1979 to 1980. In 1981, the
Arizona Department of Health Services (ADHS) installed three monitoring wells on site, in one
of which volatile organic compounds (VOCs) have been detected. Approximately 350 people
draw drinking water from private wells, and 2,800 acres of farmland are irrigated by wells within
3 miles of the site. The distance to the nearest residence is 1 mile. Hassayampa River, an
intermittent stream, is 3/4 mile east of the landfill.
Site Responsibility:
This site is being addressed through
Federal and potentially responsible
parties' actions.
NPL LISTING HISTORY
Proposed Date: 06/10/86
Final Date: 07/22/87
Threats and Contaminants
Ambient air contains very low levels of VOCs. Groundwater sampling results also
have identified various VOCs. Soils beneath the waste pits contain VOCs, heavy
metals, pesticides, and lime wastes. Potential health risks may exist for individuals
who ingest the contaminated groundwater or inhale volatilized contaminants.
27
April 1991
-------
Cleanup Approach
This site is being addressed in a single long-term remedial phase focusing on cleanup of the entire
site.
Response Action Status
Entire Site: Under EPA monitoring, the parties potentially responsible for the
contamination initiated an investigation in 1988 to determine the type and extent of
contamination at the site and to identify alternative technologies for the cleanup. The
investigation was completed in 1991. The EPA is conducting a risk assessment, scheduled for
completion in late 1991, to determine the level of risk to area residents and the surrounding
environment.
Site Facts: In 1987, the EPA sent Special Notice Letters informing 108 individuals and
companies of their potential responsibility for wastes contaminating the site.
Environmental Progress
After adding this site to the NPL, the EPA performed preliminary investigations and determined that
the Hassayampa Landfill site does not pose an immediate threat to public health or the environment.
The EPA will review the results of the ongoing risk assessment to determine if interim cleanup
actions are necessary to reduce the potential for exposure to hazardous waste sources at the site
while further studies are taking place and cleanup activities are being planned.
April 1991 28 HASSAYAMPA LANDFILL
-------
INDIAN BEND
WASH AREA
ARIZONA
EPA ID# AZD980695969
EPA REGION 9
CONGRESSIONAL DIST. 04
Maricopa County
Parts of Scottsdale, Tempe, and Phoenix, and the Salt
River Indian Reservation
Site Description
The Indian Bend Wash Area site is over 6 miles in length and covers 13 square miles. In 1981,
the cities of Scottsdale and Phoenix discovered volatile organic compounds (VOCs) in seven
municipal supply wells. These contaminants appear to have originated from several industrial
facilities that operated in the northern portion of the Indian Bend Wash area (NffiW); two of
these facilities, Motorola and Beckman, are located upgradient from five municipal water wells.
Six of seven contaminated wells were removed from service shortly after discovery; the seventh
was equipped with a treatment service to remove VOCs, then was returned to full service. Some
facilities at the southern portion of the Indian Bend Wash area (SIBW) have discharged VOCs
into the ground; other facilities may have discharged heavy metals, cyanides, and acids.
Landfills at this area have received a variety of hazardous materials, including vinyl chloride and
foundry slag. Approximately 70% of the City of Scottsdale's municipal water needs are supplied
by groundwater. Approximately 130,000 people live in Scottsdale.
Site Responsibility:
This site is being addressed through
Federal and potentially responsible
parties' actions.
NPL LISTING HISTORY
Proposed Date: 12/30/82
Final Date: 09/08/83
Threats and Contaminants
Groundwater is contaminated with VOCs, boron, chloroform, lead, and zinc. Soil is
contaminated with VOCs, cyanides, acids, and heavy metals including chromium and
lead. Surface water also contains VOCs. People could be exposed to chemicals from
the site if they accidentally ingest or come in direct contact with contaminated
groundwater, soil, or surface water. Groundwater at the site is used to irrigate various
crops and feed livestock. Contaminants could bioaccumulate in agricultural products
that use contaminated groundwater.
29
April 1991
-------
Cleanup Approach
This site is being addressed in six long-term remedial phases focusing on cleanup of: the Northern
Indian Bend Wash area, the Scottsdale area, the Southern Indian Bend Wash area, the Beckman
Industries area, the Motorola area, and the Siemens area.
Response Action Status
Northern Indian Bend Wash: The EPA is addressing the NIBW as a separate area of
study from SIBW, because the contaminants may come from a different source. An
investigation into the extent and type of contamination was begun in 1984. The
investigation is scheduled to be completed in 1991 and will include recommendations on the best
alternatives for cleaning up the site.
Scottsdale Area: In 1988, the EPA selected a cleanup alternative, which included:
containment of contaminants by extracting groundwater from the middle and lower parts
of the aquifer and by pumping five City of Scottsdale wells and air stripping to clean the
contaminated groundwater. The remedy includes granular activated carbon to extract the
contaminants from the stream of air. In 1990, the potentially responsible parties installed wells that
will be used to monitor the effectiveness of the cleanup process. The parties are scheduled to
complete the design of the cleanup activities by 1991 and finish the cleanup work in 1994.
Southern Indian Bend Wash: The EPA began a study of the nature and extent of
contamination at SIBW in 1988. The study report, which will be concluded in three
phases, will include alternative recommendations for final cleanup of the site. Decisions
on all three phases are expected in 1993.
Beckman Industries Area: The EPA began an investigation into the nature and extent
of contamination at this area in 1984, and it is scheduled to be completed in 1991. Based
on the results of the investigation, a remedy will be selected to clean up Beckman area.
Motorola Area: The potentially responsible parties began an investigation into the
nature and extent of contamination at the area in 1984 and expect to complete the
investigation in 1991. At that time, recommendations will be made determining the most
effective methods for cleaning up this area.
Siemens Area: The potentially responsible parties began a study of the nature and
extent of contamination at this area in 1989 and expect to complete it in 1991. A remedy
to address the cleanup of this area will be selected based on the results of the investigation.
Environmental Progress
After adding this site to the NPL, the EPA performed preliminary investigations and determined that
no immediate actions were required at the Indian Bend Wash site while further studies are taking
place and cleanup activities are being planned.
April 1991 30 INDIAN BEND WASH AREA
-------
LITCHFIELD
AIRPORT AREA
ARIZONA
EPA ID# AZD980695902
Site Description
EPA REGION 9
CONGRESSIONAL DIST. 03
Maricopa County
Goodyear
Other Names:
Phoenix-Goodyear Airport Area
Litchfield Airport Industrial Area
Phoenix-Litchfield Airport Area
The Litchfield Airport Area is a 40-square-mile site that covers a portion of the present Phoenix-
Goodyear Airport. In 1981, the Arizona Department of Health Services discovered contaminated
groundwater near the airport. The State also found contaminated groundwater at Unidynamics, a
facility located to the north of the site. Soils were found to contain trichloroethylene (TCE) at
both areas. The EPA sampled 89 wells in the area. Although 43 of these wells were found to
contain TCE at levels that exceed Federal health standards, no water containing contaminants
above these levels has been used in the municipal supply system since 1981. Since 1983, the
EPA has been working to study the nature and extent of contamination at the site. The EPA is
conducting a joint study with the Arizona Department of Environmental Quality, the Arizona
Department of Water Resources, Goodyear Tire & Rubber Company (Goodyear), the U.S.
Department of Defense (DoD), and Unidynamics Phoenix, Inc. (Unidynamics). The combined
population of Avondale and Goodyear is approximately 30,000 people.
Site Responsibility:
This site is being addressed through
Federal, State, and potentially
responsible parties' actions.
NPL LISTING HISTORY
Proposed Date: 12/30/82
Final Date: 09/01/83
Threats and Contaminants
Groundwater and soil contain volatile organic compounds (VOCs) and chromium.
The EPA concluded that, although TCE and other chemicals contaminate the
groundwater in the vicinity of the site, the risk to people is minimal because the
contaminated groundwater currently is not being used for drinking water. Although
the cities of Goodyear and Avondale use groundwater for their drinking water
supplies, their drinking water currently meets all State and Federal standards.
Cleanup Approach
This site is being addressed in four long-term remedial phases that focus on cleanup of
contamination that affects the entire site, cleanup of the Airport Treatment Plant/Section 16, cleanup
of the Unidynamics area, and cleanup of the southern portion of the site.
31
April 1991
-------
Response Action Status
Entire Site: In 1989, the EPA selected two methods to address contamination at the
site: pumping and treating contaminated groundwater through air stripping and vacuum
extracting soil vapors, using carbon treatment to control emissions. The EPA began the
design of these components in 1991. Cleanup of the site is scheduled to begin in late 1992.
Airport Treatment Plant/Section 16: In 1987, the EPA selected a cleanup strategy
to control the movement and level of contaminants in the shallow groundwater directly
below the site. Water from the shallow groundwater will be pumped from beneath a
portion of the site where the highest levels of contaminants have been detected. The extracted water
will be treated through air stripping and returned to the shallow groundwater system. Goodyear Tire
and Rubber began to pump and treat the shallow groundwater under the site in 1989. Consideration
is being given to expanding the number of extraction and injection wells.
Unidynamics: In 1989, the EPA selected a cleanup remedy that includes a soil vapor
extraction system to treat contaminated soil and a groundwater pump and treat system.
Unidynamics began to design the selected remedy in early 1991 and is scheduled to begin
cleanup of the contamination at this area in 1992.
Southern Portion: In 1989, the EPA selected a cleanup remedy to address
contamination at this area that includes a soil vapor extraction system to treat
contaminated soil and a pump and treat system for treatment of contamination in the deep
groundwater. Engineering design of the remedies is planned to begin in late 1991, with cleanup
scheduled to begin in 1992.
Site Facts: In 1988, the EPA, the DoD, and the Goodyear Tire & Rubber Company finalized an
agreement, whereby Goodyear Tire will carry out cleanup activities for part of the shallow
groundwater contaminated under the southern section of the site. In 1990, the EPA issued
Unidynamics a Unilateral Administrative Order to design and implement all cleanup work required
for the northern section of the site. In 1991, the EPA, Goodyear Tire and Rubber Co., Loral Defense
Systems Arizona, and the State of Arizona signed a Consent Decree, whereby Goodyear Tire will
design and implement soil and deep groundwater cleanup activities.
Environmental Progress
A water treatment facility has been constructed and currently is in operation at the Litchfield
Airport Area site to reduce contamination of the shallow groundwater. Remedies have been
selected at the remaining portions of the site that, once underway, will address other
contaminated groundwater resources and soils.
April 1991 32 LITCHFIELD AIRPORT AREA
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LUKE AIR FOR
BASE
ARIZONA
EPAID#AZ0570024133
EPA REGION 9
CONGRESSIONAL DIST. 03
Maricopa County
Glendale
Site Description
Construction of the 4,198-acre Luke Air Force Base (LAFB) site began in 1941, with the
primary mission of providing advanced flight training to fighter pilots. Discharges and waste
disposal practices at LAFB resulted in soil and groundwater contamination. Thirty-two areas of
the base are subject to further investigation: two fire training areas; a waste oil and fuels
underground storage tank area; 3 waste oil disposal trench areas; 3 surface drainage canals
receiving oily wastes; a sewage treatment plant effluent canal; the site of an abandoned Defense
Reutilization and Marking Office; thirteen land disposal sites (one of which contains a
radiological disposal area); an old incinerator site; a former outside transformer storage site; 2
leaking underground storage tank sites; an abandoned surface impoundment; an ammunition
storage area; a skeet range; and the base production wells. Contaminants on site include organic
solvents and paint strippers, waste oil spills, petroleum spills, metal plating wastes, hydraulic
fluids, and radiological wastes. There are approximately 4,900 military personnel and
dependents living on base. Civilian and other military personnel who commute to the base daily
from off base areas brings the total daily base population to approximately 8,000. The cities of
Goodyear, Youngtown, and Phoenix depend on the water from the Phoenix groundwater basin
that underlies the site for drinking water supplies.
Site Responsibility:
This site is being addressed through
Federal actions.
NPL LISTING HISTORY
Proposed Date: 07/14/89
Final Date: 08/30/90
Threats and Contaminants
Groundwater and soil are contaminated with volatile organic compounds (VOCs)
resulting from the diverse processes that have taken place on the site. Potential
human health hazards include accidental ingestion or direct contact with
contaminated materials.
33
April 1991
-------
Cleanup Approach
This site is being addressed in two stages: initial actions and two long-term remedial phases
focusing on cleanup of the entire site and soil contamination.
Response Action Status
Initial Actions: Completed initial cleanup actions include closing a former waste oil and
contaminated fuel storage site, removing the tanks and capping the area with concrete, and
installing monitoring wells. In 1990, soil around the Agua Fria River was stabilized. In
addition, a vapor extraction system is being used to remove VOCs from soils in the North Fire
Training Area.
Soil Contamination: An investigation into the soil contamination at the site began in
1990. At the conclusion of the investigation, scheduled for 1993, alternative
recommendations will be made for cleanup of the site.
Entire Site: The EPA began oversight of the basewide investigation into the extent and
type of contamination in 1990. At the conclusion of the investigation, scheduled for 1994,
alternative recommendations will be made for cleanup of the remaining contamination
areas identified at the site.
Site Facts: The Luke Air Force Base site is participating in the Installation Restoration Program, a
specially funded program established by the Department of Defense (DoD) in 1978 to identify,
investigate, and control the migration of hazardous contaminants at military and other DoD facilities.
A Federal Facilities Agreement to conduct the site cleanup plan was signed in September 1990.
Under the terms of this agreement, a basewide investigation and remedy selection is expected to be
drafted by 1994.
Environmental Progress
Closing the waste oil and fuel storage site, removing tanks, capping the area, and installing
monitoring wells have greatly reduced the potential for exposure to hazardous materials at the Luke
Air Force Base site while further studies and cleanup activities are being planned.
April 1991 34 LUKE AIR FORCE BASE
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MOTOROLA, IN
(52ND STREET
PLANT)
ARIZONA
EPAID#AZD009004177
EPA REGION 9
CONGRESSIONAL DIST. 01
Maricopa County
Phoenix
Other Names:
Motorola, Inc. Discrete Semiconductor
Site Description
Motorola, Inc. (52nd Street Plant) manufactures semiconductors and related components on this
90-acre site, using solvents in the production process. In 1983, Motorola tested some
underground storage tanks for leaks. Results showed that one tank containing volatile organic
compounds (VOCs) was leaking. Further investigations determined the groundwater and soil
were contaminated. Motorola detected contamination in monitoring wells at least a mile from
the facility. Although the site lies in an area with drinking water provided by municipal water
service, 28 private wells have been identified around the site. Water for irrigation is provided by
the Salt River Project. Approximately 500 residents live within 1 mile of this NPL site.
Site Responsibility:
This site is being addressed through
Federal, State, and potentially
responsible parties' actions.
NPL LISTING HISTORY
Proposed Date: 10/15/84
Final Date: 10/04/89
Threats and Contaminants
Groundwater underlying the site, soil, and soil gas contain various VOCs from
solvent use at the site. People who accidentally ingest or come into direct contact
with contaminated groundwater and soil may be at risk.
35
April 1991
-------
Cleanup Approach
This site is being addressed in three stages: initial actions and two long-term remedial phases
that both focus on cleanup of the contaminated groundwater plume.
Response Action Status
Initial Actions: Motorola has taken several interim actions to monitor and develop
treatment remedies for contaminated groundwater. In 1983 and 1984, Motorola installed
22 on-site and 6 off-site monitoring wells. In 1986, additional monitoring wells were
installed. The company also initiated an on-site groundwater treatment program that included
treatability testing, design, and installation of a pilot treatment plant; treatment of groundwater, and
use of the effluent in the plant's air fume scrubbers.
Groundwater Plume (First Action): In 1988, the EPA selected a remedy to clean a
portion of the site by recovering the soil gas and groundwater and treating them in an on-
site facility. Soil gas from the main source areas will be extracted, and alluvial
groundwater will be pumped. In addition, off-site groundwater also will be pumped. Both the soil
gas and the contaminated groundwater will be treated by carbon adsorption at the facility. The
treated groundwater then will be used in the manufacturing processes, replacing potable water
supplied by the City of Phoenix. Motorola, under State monitoring, is designing the technical
specifications for the cleanup. Currently, extraction wells are being drilled and pipes to the
treatment facility are being laid.
Groundwater Plume (Second Action): Motorola, under State monitoring, is
conducting an investigation of the remaining portion of the contaminant plume. Once this
investigation is completed, scheduled for 1992, measures will be recommended for site
cleanup.
Environmental Progress
After adding this site to the NPL, the EPA performed preliminary investigations and determined that
no other immediate actions, besides the initial treatment of groundwater by Motorola, were required
at the Motorola, Inc. site while further studies are taking place and cleanup activities are being
designed.
April 1991 36 MOTOROLA INC.
(52ND STREET PUNT)
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MOUNTAIN VIEW
MOBILE HOMES
ARIZONA
EPA ID# AZD980735724
Site Description
EPA REGION 9
CONGRESSIONAL DIST. 04
Gila County
2 miles from Globe
Other Names:
Globe Site
The 17-acre Mountain View Mobile Homes site was developed in 1973 on the site of the former
Metate Asbestos Corporation's chrysotile asbestos mill. In 1979, asbestos contamination of the
site was discovered by local health officials inspecting the waste disposal system. Small piles of
asbestos mill tailings were found against the abandoned mill structures and the adjacent railroad
tracks. Before 1973, three mills in the area processed chrysotile asbestos ore from nearby mines.
Because they failed to meet new EPA standards for emissions, two of the mills were ordered
closed by the County in 1973. Before closing, however, the owner of one of the mill sites
obtained a permit to rezone the property into a residential subdivision. Asbestos mill tailings
were used as primary landfill material before the site was partially covered with topsoil. Before
it shut down, this mill continued operations for several weeks while residents were moving into
the mobile home community. The mill buildings and asbestos-laden equipment remained
standing in the middle of the mobile homes. The third mill, with its large pile of asbestos mill
tailings, continued to operate a few hundred yards from the mobile homes. Approximately 100
to 130 people lived in the mobile home park. The Town of Globe has a population of 8,000, and
the adjacent town of Miami has 3,000 residents.
Site Responsibility: This site was addressed through Federal
and State actions.
NPL LISTING HISTORY
Proposed Date: 12/30/82
Final Date: 09/01/83
Deleted Date: 04/18/88
Threats and Contaminants
The air and soils on the site were shown to be contaminated with asbestos. Prior
to site cleanup, area residents who came in direct contact with or accidentally
ingested the asbestos-containing soil may have been at risk. In addition, inhaling
asbestos fibers posed a potential for adverse health effects.
37
April 1991
-------
Cleanup Approach
This site was addressed in two stages: initial actions and a single long-term remedial phase that
focused on cleanup of the entire site.
Response Action Status
Initial Actions: In 1980, the State provided temporary housing for the residents while
the site was being decontaminated. The old mill buildings were demolished, and topsoil
was used to cover the contaminated soil. Wind, water, and human activity soon eroded the
soil covering, which exposed the asbestos tailings again.
Entire Site: In 1983, the EPA selected a remedy to clean up the site by permanently
relocating the mobile home residents; cleaning the site and demolishing and burying on
site all the homes and sewage treatment plant; closing the site by covering it with either
clay or a synthetic material, placing clean soil on top of the site; fencing the area; and periodically
inspecting and maintaining the site. Permanent relocation of all residents was completed in 1985,
and ownership of the purchased property was transferred to the State. Following relocation of the
residents, the site was cleaned up. The homes and other structures were crushed and buried on site
in two natural depressions. Drainage culverts and enclosed pipes were installed to reduce the
potential for erosion of the cover soils. A filter fabric was placed over the entire site to act as a
physical barrier to upward movement of asbestos fibers and to prevent erosion. Clean soil was
placed over the filter fabric, and compacted and crushed rock was added to complete the cover. The
site was fenced to protect the integrity of the cover. The State has agreed to maintain the site for a
minimum of 20 years. The EPA and the State have determined that the site is protective of human
health and the environment and that no further cleanup is required. The site was deleted from the
NPLinl988.
Site Facts: The Metate Asbestos mill was ordered closed by the Gila County Air Quality Control
District in 1973.
Environmental Progress
The numerous cleanup and relocation activities described above have eliminated the potential of
exposure to asbestos-laden materials at the Mountain View Mobile Homes site. Area residents have
been permanently relocated, and cleanup actions have successfully controlled site contamination.
The EPA and the State have determined that the site is now safe for nearby residents and the
environment and have deleted the site from the NPL.
April 1991 38 MOUNTAIN VIEW MOBILE HOMES
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NINETEENTH
AVENUE LANDFILL
ARIZONA
EPAID#AZD980496780
Site Description
EPA REGION 9
CONGRESSIONAL DIST. 02
Maricopa County
Phoenix
Other Names:
Salt River Landfills
The 213-acre Nineteenth Avenue Landfill site operated as a sanitary landfill between 1957 and 1979.
One 200-acre portion of the site, Cell A, is located on the northern bank of the Salt River. A 13-acre
portion of the landfill, Cell A-l, is located on the southern bank of the Salt River. In the past, sand
and gravel companies excavated material along a 7-mile stretch of the Salt River. The City of
Phoenix took over several of these pits for use as waste disposal sites. The Nineteenth Avenue
Landfill accepted municipal, radioactive, hospital, and industrial wastes. Portions of the landfill are
within the 100-year flood plain of the Salt River. Early in 1979, the river flooded, raising the water
table and filling several pits. The high water also breached several dikes, opening landfill cells and
causing refuse to wash into the river. Water also infiltrated directly into the cells, increasing the
potential for leachate movement. Leachate is being generated from the site and is contaminating the
groundwater. In addition, saturation of the waste has generated excess amounts of methane gas. The
landfill was closed by the State in 1979. The population within 6 miles is approximately 6,000
people. The nearest residence is 1/3 mile from the site. The area's primary drinking water is
provided by the City of Phoenix water distribution system. The municipal system draws water from
surface water sources over 30 miles away. The nearest drinking water supply well is over 3 miles
away. An industrial well and an agricultural well are located 200 feet and 800 feet from the site.
Site Responsibility: This site is being addressed through
Federal and potentially responsible
parties' actions.
NPL LISTING HISTORY
Proposed Date: 12/30/82
Final Date: 09/01/83
Threats and Contaminants
Groundwater contains volatile organic compounds (VOCs); heavy metals including
arsenic, barium, mercury, and nickel; and beta radiation. Refuse in the landfill contains
VOCs and pesticides. Soil contains VOCs, polychlorinated biphenyls (PCBs), and
pesticides. The generation and migration of methane gas is a potential hazard. Methane
may collect and reach explosive levels in enclosed buildings or other structures adjacent
to the site. Soil, groundwater, and refuse are contaminated; however, the possibility of
human exposure to these contaminants is unlikely, since there are no residential areas
within 1/4 mile of the site, and groundwater is not used for drinking water. Area
residents and site workers who come in direct contact with or accidentally ingest the
contaminated groundwater, soil, or refuse may suffer adverse health effects.
39
April 1991
-------
Cleanup Approach
This site is being addressed in two stages: immediate actions and a long-term remedial phase
focusing on cleanup of the entire site.
Response Action Status
Immediate Actions: Earthen berms were constructed on the site to limit access. The
site was covered with sand, gravel, and stones. In 1981, the City installed a system to
collect methane gas and also installed monitoring wells to sample the groundwater.
Entire Site: In 1989, the EPA selected a remedy to clean up the landfill by: (1)
installing a gas collection and treatment system; (2) covering the landfill with clay or a
synthetic material to prevent water from coming into contact with the buried materials;
and (3) preventing erosion of the landfill by the construction of bank protection levees between the
river and the landfill. In 1990, the City of Phoenix began designing the technical specifications to
clean up the site. Once the design phase is completed, scheduled for 1994, cleanup activities will
begin.
Environmental Progress
Methane control devices installed at the site have eliminated the potential for gas accumulation and
explosion at the site. The construction of berms, covering of the site, and the installation of
monitoring wells have reduced the potential for exposure to contaminated materials while cleanup
remedies are being designed and constructed at the Nineteenth Avenue Landfill site.
April 1991 40 NINETEENTH AVENUE LANDFILL
-------
TUCSON
INTERNATION
AIRPORT AREA
ARIZONA
EPA ID# AZD980737530
Site Description
EPA REGION 9
CONGRESSIONAL DIST. 02
Pima County
Tucson
Other Names:
Hughes Aircraft Company
USAF Plant 44
The 24-square-mile Tucson International Airport Area (TIAA) site includes the Tucson
International Airport, portions of the San Xavier Indian Reservation, residential areas of the
Cities of Tucson and South Tucson, and the Air Force Plant #44/Hughes Aircraft Company
facility. At least 20 facilities have operated in the TIAA area since 1942, including aircraft and
electronics facilities, which discharged waste liquids directly into the soil; fire drill training
areas, where wastes from training operations were left in unlined pits; and unlined landfills,
which received various wastes from several sources. The first indications of groundwater
contamination at TIAA appeared in the early 1950s, when elevated levels of chromium were
detected in a municipal supply well adjacent to the U.S. Air Force Plant #44. The U.S. Air Force
Plant #44, which has been operated under contract by the Hughes Aircraft Company (HAC)
since 1951, is believed to be a major contributor to groundwater contamination. The facility
used trichloroethylene (TCE) as a metal degreaser and chromium in electroplating. Wastewater
and spent solvents were discharged into unlined ditches or disposed of in waste pits and ponds.
Surface water flowed off HAC property and onto the San Xavier Reservation. Beginning in
1976, lined wastewater holding ponds were constructed to receive wastewater discharges. The
State also closed a well at the plant because of high levels of chromium. A second source of
contamination at the TIAA site is believed to be the Tucson Airport Hangar Area, which was
occupied by various defense contractors from 1942 to 1958. During this period, volatile organic
compounds (VOCs) were used and disposed of on site and in the airport landfill. Other more
recent occupants of the hangar also may have contributed to the groundwater contamination.
Sources of contamination at the northern and eastern edges of the airport are believed to be the
Arizona Air National Guard, the Burr-Brown Corporation, and West-Cap Arizona. The
localized groundwater contamination due to these operations is situated east of the main
contaminant plume. The City of Tucson is dependent on groundwater for its water supply.
Before the discovery of groundwater contamination, wells within the site boundaries provided
water for over 47,000 people. The Santa Cruz River borders the site.
Site Responsibility: This site is being addressed through
Federal, State, and potentially
responsible parties' actions.
NPL LISTING HISTORY
Proposed Date: 12/30/82
Final Date: 09/01/83
41
April! 991
-------
Threats and Contaminants
IT
Groundwater underlying the site and soil contain VOCs and chromium. People who
come in direct contact with or accidentally ingest contaminated groundwater and soil may
be at risk.
Cleanup Approach
This site is being addressed in three stages: immediate actions and two long-term remedial phases
focusing on cleanup of groundwater and soils.
Response Action Status
Immediate Actions: In 1981, the City of Tucson began closing all municipal wells that
exceeded the State levels and notified private well users of potential risks. Since 1987, the
Air Force has been extracting and treating groundwater in the southern portion of the site.
By 1987, 35 lined wastewater holding ponds had been constructed to receive process wastewater.
Groundwater: In 1988, the EPA selected a remedy to treat the groundwater in the
northern portion of the site by pumping and treating the contaminated groundwater, using
packed column aeration, followed by discharging the treated water to the municipal water
distribution system and treating the emissions from the treatment process using granular activated
carbon. The parties potentially responsible for site contamination, under EPA monitoring, are
designing the technical specifications for the groundwater pump and treat system. Once the design
phase is completed, scheduled for 1992, the cleanup activities will begin.
Soils: In 1990, the potentially responsible parties, under EPA monitoring, began an
investigation to determine the type and extent of soil contamination on airport property.
This investigation is expected to be completed in 1993, at which time measures will be
recommended for soil cleanup.
Site Facts: In 1989, the EPA issued an Administrative Order to the parties potentially responsible
for site contamination requiring them to clean up the groundwater and soil.
Environmental Progress
Contaminated drinking supplies have been removed from service, and initial actions have been taken
to control further contamination at the site by treating contaminated groundwater. Additional
cleanup remedies currently are being designed or planned that will address remaining contamination
areas and will restore the site to safety levels.
April 1991 42 TUSCON INTERNATIONAL AIRPORT AREA
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WILLIAMS AIR
FORCE BASE
ARIZONA
EPA ID# AZ7570028582
EPA REGION 9
CONGRESSIONAL DIST. 01
Maricopa County
Chandler
Site Description
The 4,127-acrc Williams Air Force Base (WAFB) site was commissioned as a flight training school
in 1941. Contaminants from base activities include organic solvents and paint strippers, petroleum
spills, metal plating wastes, hydraulic fluids, pesticides, and radiological wastes. Discharges and
disposal at WAFB have resulted in soil and groundwater contamination. Thirteen subsites have been
identified as potentially contaminated areas including two fire training areas, a fuel storage area, two
surface storm drainage areas, a hazardous material storage area, a landfill, a pesticide burial pit, a
radiological disposal area, and four underground storage tanks. Approximately 3,000 military
personnel are stationed at WAFB, as well as 860 civilian employees. Many of the military personnel
live off base in one of the surrounding towns. The total population living on base, including
dependents, is approximately 2,700. On an average workday, the population of the base rises to over
5,000.
Site Responsibility: This site is being addressed through
Federal actions.
NPL LISTING HISTORY
Proposed Date: 07/14/89
Final Date: 11/21/89
Threats and Contaminants
Groundwater contains volatile organic compounds (VOCs), nitrates, and heavy metals
including lead, cadmium, nickel, and chromium. Soils also contain various VOCs from
past disposal practices. Accidental ingestion of contaminated soil and groundwater are
potential health hazards.
Cleanup Approach
This site is being addressed in three stages: initial actions and two long-term remedial phases
focusing on cleanup of the entire site and the Liquid Fuels Storage Area.
43
April 1991
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Response Action Status
Initial Actions: The Southwest Drainage System was stabilized in 1988 by installing a
soil cement and concrete cap on the ditch. A number of monitoring wells were installed
and the hydrogeology of the area is being investigated. In 1991, a small pesticide drum
burial site was excavated. Radiological materials will be removed from another burial site and
disposed of. The removal of approximately 20 underground storage tanks and free product removal
also is planned for 1991.
Entire Site: The EPA began oversight of the Air Force's investigation at the site that
will determine the nature and extent of the contamination at all impacted areas of the base.
The results of the investigation are expected in early 1994 and will be used to evaluate
different cleanup methods.
Liquid Storage Area: In 1990, an investigation into the type and extent of
contamination was initiated at the waste liquids storage area. At the conclusion of the
investigation, scheduled for late 1992, alternative recommendations for cleanup of the area
will be presented and evaluated to select a final cleanup strategy.
Site Facts: Williams Air Force Base is participating in the Installation Restoration Program, a
specially funded program established by the Department of Defense (DoD) in 1978 to identify,
investigate, and control the migration of hazardous contaminants at military and other DoD facilities.
Environmental Progress
Cleaning the Southwest Drainage System, installing monitoring wells, and removing pesticide drums
and radiological materials have reduced the potential for exposure to contaminated materials at the
Williams Air Force Base site while studies are taking place and cleanup activities are being planned.
April 1991 44 WILLIAMS AIR FORCE BASE
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YUMA MARINE
CORPS AIR
STATION
ARIZONA
EPA ID#AZ0971590062
Site Description
EPA REGION 9
CONGRESSIONAL DIST. 02
Yuma County
2 miles from Yuma
Since the mid-1950s, large volumes of waste fuels and solvents from refueling and servicing of
airplanes have been disposed of directly onto the ground or into unlined pits at the 3,000-acre
Yuma Marine Corps Air Station site. In addition, combustible materials such as fuel oil and
organic solvents have been deposited on the ground and burned during fire training exercises.
The Navy has identified volatile organic compounds (VOCs) in soil at the site. Approximately
5,700 people live on site and usually obtain their drinking water from the Colorado River
through an irrigation canal. However, during maintenance work on the canal that lasts for one
month each year, drinking water comes from an on-station well. An additional 3,300 base
employees use water from this well. The city of Yuma is 2 miles from the site, with a summer
population of 60,000 and a winter population of 180,000. The city uses groundwater for
drinking water purposes. Groundwater also supplies agricultural and industrial users.
Site Responsibility:
This site is being addressed through
Federal actions.
NPL LISTING HISTORY
Proposed Date: 06/24/88
Final Date: 02/22/90
Threats and Contaminants
Groundwater and soils on the site contain various VOCs and other contaminants
including residues from tear gas, ammunition, napalm, paints, and photographic
processing chemicals. The contaminated soil could pose a health hazard to individuals if
it is directly contacted or accidentally ingested. The Colorado River, which runs close to
the site, could become polluted from the site contaminants.
Cleanup Approach
This site is being addressed in a single long-term remedial phase focusing on cleanup of the entire
site.
45
April 1991
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Response Action Status
Entire Site: The Marine Corps is planning to conduct an investigation to evaluate the
nature and extent of the site contamination. The results of the study will be used to
evaluate different cleanup alternatives and to select the preferred method for long-term
protection of human health and the environment.
Site Facts: Yuma Marine Corps Air Station is participating in the Installation Restoration
Program, a specially funded program established by the Department of Defense (DoD) in 1978 to
identify, investigate, and control the migration of hazardous contaminants at military and other DoD
facilities.
Environmental Progress
After adding this site to the NPL, the EPA performed preliminary investigations and determined that
no immediate actions were required at the Yuma Marine Corps Air Station site while further studies
and cleanup activities are being planned.
April 1991
46
YUMA MARINE CORPS AIR STATION
-------
THE NPL FACT SHEETS
0
Summary
of Site
Activities
EPA REGION 9
47
April 1991
-------
Who Do I Call with Questions?
The following pages describe each NPL site in Nevada, providing specific
information on threats and contaminants, cleanup activities, and environmen-
tal progress. Should you have questions, please call the EPA's Region 9
Office in San Francisco, California or one of the other offices listed below:
EPA Region 9 Superfund Community Relations Office (415) 744-2175
EPA Region 9 Superfund Office
EPA Superfund Hotline
EPA Headquarters Public Information Center
Nevada Superfund Office
(415) 744-2356
(800) 424-9346
(202) 260-2080
(702) 677-5872
April 1991
48
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CARSON RIVE
MERCURY SIT
NEVADA
EPA ID#NVD980813646
Site Description
EPA REGION 9
CONGRESSIONAL DIST. 01
Lyon and Churchill Counties
The Carson River Mercury Site consists of a 50-mile stretch of the Carson River, beginning
between Carson City and Dayton and extending downstream through the Lahontan Reservoir,
which has been contaminated by mercury used in the amalgamation of gold and silver. In the
late 1800s, large amounts of mercury were used during the milling of the Comstock Lode near
Virginia City. Ore mined from the lode was transported to mill sites, where it was crushed and
mixed with mercury to amalgamate the precious metals. Of the original 75 sites, 12 sites along
the Carson River in the Brunswick Canyon area frequently were used because of the availability
of water power. Mercury mine tailings, resulting from the mill site operations, have been found
5 miles up Brunswick Canyon, 3 miles up Six Mile Canyon, and within the Carson Plains. Areas
near the Comstock Lode where extensive mining occurred, such as Gold Canyon, also may be
major sources of mercury-contaminated mine tailing piles. Annual rains transport mercury from
the tailings piles in the canyons to the Carson River, where the Nevada Division of
Environmental Protection (NDEP) has documented extensive mercury contamination. The
NDEP sampled the water and sediments from the Carson River and found elevated levels of
mercury attributed to the tailings piles in various areas of the Carson River. Approximately
1,400 people obtain drinking water from wells within 3 miles from the site, the nearest being
within 2,000 feet of the site.
Site Responsibility:
This site is being addressed through
Federal and State actions.
NPL USTING HISTORY
Proposed Date: 10/04/89
Final Date: 08/30/90
Threats and Contaminants
Groundwater, surface water, sediments, and soils at site areas are contaminated with
mercury. Possible health threats include direct contact with or accidental ingestion
the contaminants. Additionally, runoff from contaminated site areas may facilitate
the spread of contamination to other unaffected environments.
49
April 1991
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Cleanup Approach
This site is being addressed in two stages: initial actions and a long-term remedial phase focusing on
cleanup of the entire site.
Response Action Status
Initial Actions: In 1991, seven tailings piles containing mercury-contaminated dust
were excavated and removed from the site. Concerns over possible exposure of vehicle
users to contaminated materials prompted this removal. Currently, workers are removing
two tailings piles, also contaminated with mercury, in the Dayton area to eliminate health risks posed
to children who play in the area. All contaminated materials are being transported to a mineral
resource recovery facility.
Entire Site: The EPA began conducting an investigation into the nature and extent of
contamination at the site in 1990. A final remedy to clean up the site will be selected,
based on the results of the investigation.
Environmental Progress
Excavation and removal of contaminated tailings piles from the Carson River Mercury Site have
reduced the potential of exposure to contaminated dust while further studies are taking place and
cleanup actions are being planned.
April 1991 50 CARSON RIVER MERCURY SITE
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APPENDIX A
Glossary:
Terms Used
in the
Fact Sheets
51
-------
GLOSSARY
This glossary defines terms used
throughout the NPL Volumes. The
terms and abbreviations contained in
this glossary apply specifically to work
performed under the Superfund program in
the context of hazardous waste management.
These terms may have other meanings when
used in a different context.
Terms Used
in the NPL
Book
Acids: Substances, characterized by low pH
(less than 7.0), that are used in chemical
manufacturing. Acids in high concentration
can be very corrosive and react with many
inorganic and organic substances. These
reactions possibly may create toxic com-
pounds or release heavy metal contaminants
that remain in the environment long after the
acid is neutralized.
Administrative Order On Consent: A legal
and enforceable agreement between the EPA
and the parties potentially responsible for site
contamination. Under the terms of the Order,
the potentially responsible parties (PRPs)
agree to perform or pay for site studies or
cleanups. It also describes the oversight rules,
responsibilities, and enforcement options that
the government may exercise in the event of
non-compliance by potentially responsible
parties. This Order is signed by PRPs and the
government; it does not require approval by a
judge.
Administrative Order [Unilateral]: A
legally binding document issued by the EPA,
directing the parties potentially responsible to
perform site cleanups or studies (generally,
the EPA does not issue Unilateral Orders for
site studies).
Aeration: A process that promotes break-
down of contaminants in soil or water by
exposing them to air.
Agency for Toxic Substances and Disease
Registry (ATSDR): The Federal agency
within the U.S. Public Health Service charged
with carrying out the health-related responsi-
bilities of CERCLA.
Air Stripping: A process whereby volatile
organic chemicals (VOCs) are removed from
contaminated material by forcing a stream of
air through it in a pressurized vessel. The
contaminants are evaporated into the air
stream. The air may be further treated before
it is released into the atmosphere.
Ambient Air: Any unconfined part of the
atmosphere. Refers to the air that may be
inhaled by workers or residents in the vicinity
of contaminated air sources.
Aquifer: An underground layer of rock,
sand, or gravel capable of storing water
within cracks and pore spaces, or between
grains. When water contained within an
aquifer is of sufficient quantity and quality, it
can be tapped and used for drinking or other
purposes. The water contained in the aquifer
is called groundwater. A sole source aquifer
supplies 50% or more of the drinking water of
an area.
Artesian (Well): A well made by drilling
into the earth until water is reached, which,
from internal pressure, flows up like a foun-
tain.
53
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GLOSSARY.
Attenuation: The naturally occurring pro-
cess by which a compound is reduced in
concentration over time through adsorption,
degradation, dilution, and/or transformation.
Background Level: The amount of a sub-
stance typically found in the air, water, or soil
from natural, as opposed to human, sources.
Baghouse Dust: Dust accumulated in remov-
ing particulates from the air by passing it
through cloth bags in an enclosure.
Bases: Substances characterized by high pH
(greater than 7.0), which tend to be corrosive
in chemical reactions. When bases are mixed
with acids, they neutralize each other, form-
ing salts.
Berm: A ledge, wall, or a mound of earth
used to prevent the migration of contami-
nants.
Bioaccumulate: The process by which some
contaminants or toxic chemicals gradually
collect and increase in concentration in living
tissue, such as in plants, fish, or people, as
they breathe contaminated air, drink contami-
nated water, or eat contaminated food.
Biological Treatment: The use of bacteria or
other microbial organisms to break down
toxic organic materials into carbon dioxide
and water.
Bioremediation: A cleanup process using
naturally occurring or specially cultivated
microorganisms to digest contaminants and
break them down into non-hazardous compo-
nents.
Bog: A type of wetland that is covered with
peat moss deposits. Bogs depend primarily
on moisture from the air for their water
source, are usually acidic, and are rich in plant
residue [see Wetland].
Boom: A floating device used to contain oil
floating on a body of water or to restrict the
potential overflow of waste liquids from
containment structures.
Borehole: A hole that is drilled into the
ground and used to sample soil or ground-
water.
Borrow Pit: An excavated area where soil,
sand, or gravel has been dug up for use
elsewhere.
Cap: A layer of material, such as clay or a
synthetic material, used to prevent rainwater
from penetrating and spreading contaminated
materials. The surface of the cap generally is
mounded or sloped so water will drain off.
Carbon Adsorption: A treatment system in
which contaminants are removed from
groundwater and surface water by forcing
water through tanks containing activated
carbon, a specially treated material that
attracts and holds or retains contaminants.
Carbon Disulfide: A degreasing agent
formerly used extensively for parts washing.
This compound has both inorganic and or-
ganic properties, which increase cleaning
efficiency. However, these properties also
cause chemical reactions that increase the
hazard to human health and the environment
Carbon Treatment: [see Carbon Adsorp-
tion].
Cell: In solid waste disposal, one of a series
of holes in a landfill where waste is dumped,
compacted, and covered with layers of dirt.
CERCLA: [see Comprehensive Environ-
mental Response, Compensation, and Liabil-
ity Act].
Characterization: The sampling, monitor-
ing, and analysis of a site to determine the
54
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GLOSSARY
extent and nature of toxic releases. Character-
ization provides the basis for acquiring the
necessary technical information to develop,
screen, analyze, and select appropriate
cleanup techniques.
Chemical Fixation: The use of chemicals to
bind contaminants, thereby reducing the
potential for leaching or other movement.
Chromated Copper Arsenate: An insecti-
cide/herbicide formed from salts of three toxic
metals: copper, chromium, and arsenic. This
salt is used extensively as a wood preservative
in pressure-treating operations. It is highly
toxic and water-soluble, making it a relatively
mobile contaminant in the environment.
Cleanup: Actions taken to eliminate a
release or threat of release of a hazardous
substance. The term "cleanup" sometimes is
used interchangeably with the terms remedial
action, removal action, response action, or
corrective action.
Closure: The process by which a landfill
stops accepting wastes and is shut down,
under Federal guidelines that ensure the
protection of the public and the environment.
Comment Period: A specific interval during
which the public can review and comment on
various documents and EPA actions related to
site cleanup. For example, a comment period
is provided when the EPA proposes to add
sites to the NPL. There is minimum 3-week
comment period for community members to
review and comment on the remedy proposed
to clean up a site.
Community Relations: The EPA effort to
establish and maintain two-way communica-
tion with the public. Goals of community
relations programs include creating an under-
standing of EPA programs and related ac-
tions, assuring public input into decision-
making processes related to affected commu-
nities, and making certain that the Agency is
aware of, and responsive to, public concerns.
Specific community relations activities are
required in relation to Superfund cleanup
actions [see Comment Period].
Comprehensive Environmental Response,
Compensation, and Liability Act
(CERCLA): Congress enacted the
CERCLA, known as Superfund, in 1980 to
respond directly to hazardous waste problems
that may pose a threat to the public health and
the environment. The EPA administers the
Superfund program.
Confluence: The place where two bodies of
water, such as streams or rivers, come to-
gether.
Consent Decree: A legal document, ap-
proved and issued by a judge, formalizing an
agreement between the EPA and the parties
potentially responsible for site contamination.
The decree describes cleanup actions that the
potentially responsible parties are required to
perform and/or the costs incurred by the
government that the parties will reimburse, as
well as the roles, responsibilities, and enforce-
ment options that the government may exer-
cise in the event of non-compliance by poten-
tially responsible parties. If a settlement
between the EPA and a potentially respon-
sible party includes cleanup actions, it must
be in the form of a Consent Decree. A Con-
sent Decree is subject to a public comment
period.
Consent Order: [see Administrative Order
on Consent].
Containment: The process of enclosing or
containing hazardous substances in a struc-
ture, typically in a pond or a lagoon, to pre-
vent the migration of contaminants into the
environment.
55
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GLOSSARY.
Contaminant: Any physical, chemical,
biological, or radiological material or sub-
stance whose quantity, location, or nature
produces undesirable health or environmental
effects.
Contingency Plan: A document setting out
an organized, planned, and coordinated course
of action to be followed in case of a fire,
explosion, or other accident that releases toxic
chemicals, hazardous wastes, or radioactive
materials into the environment.
Cooperative Agreement: A contract be-
tween the EPA and the States, wherein a State
agrees to manage or monitor certain site
cleanup responsibilities and other activities on
a cost-sharing basis.
Cost Recovery: A legal process by which
potentially responsible parties can be required
to pay back the Superfund program for money
it spends on any cleanup actions [see Poten-
tially Responsible Parties].
Cover: Vegetation or other material placed
over a landfill or other waste material. It can
be designed to reduce movement of water into
the waste and to prevent erosion that could
cause the movement of contaminants.
Creosotes: Chemicals used in wood preserv-
ing operations and produced by distillation of
tar, including polycyclic aromatic hydrocar-
bons and polynuclear aromatic hydrocarbons
[see PAHs and PNAs]. Contaminating
sediments, soils, and surface water, creosotes
may cause skin ulcerations and cancer
through prolonged exposure.
Culvert: A pipe used for drainage under a
road, railroad track, path, or through an
embankment.
Decommission: To revoke a license to
operate and take out of service.
Degradation: The process by which a
chemical is reduced to a less complex form.
Degrease: To remove grease from wastes,
soils, or chemicals, usually using solvents.
De minimis: This legal phrase pertains to
settlements with parties who contributed
small amounts of hazardous waste to a site.
This process allows the EPA to settle with
small, or de minimis contributors, as a single
group rather than as individuals, saving time,
money, and effort.
Dewater: To remove water from wastes,
soils, or chemicals.
Dike: A low wall that can act as a barrier to
prevent a spill from spreading.
Disposal: Final placement or destruction of
toxic, radioactive, or other wastes; surplus or
banned pesticides or other chemicals; polluted
soils; and drums containing hazardous materi-
als. Disposal may be accomplished through
the use of approved secure landfills, surface
impoundments, land farming, deep well
injection, or incineration.
Downgradient: A downward hydrologic
slope that causes groundwater to move toward
lower elevations. Therefore, wells downgra-
dient of a contaminated groundwater source
are prone to receiving pollutants.
Effluent: Wastewater, treated or untreated,
that flows out of a treatment plant, sewer, or
industrial outfall. Generally refers to wastes
discharged into surface waters.
Emission: Pollution discharged into the
atmosphere from smokestacks, other vents,
and surface areas of commercial or industrial
facilities.
Emulsifiers: Substances that help in mixing
materials that do not normally mix; e.g., oil
and water.
56
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GLOSSARY
Endangerment Assessment: A study con-
ducted to determine the risks posed to public
health or the environment by contamination at
NPL sites. The EPA or the State conducts the
study when a legal action is to be taken to
direct the potentially responsible parties to
clean up a site or pay for the cleanup. An
endangerment assessment supplements an
investigation of the site hazards.
Enforcement: EPA, State, or local legal
actions taken against parties to facilitate
settlements; to compel compliance with laws,
rules, regulations, or agreements; and/or to
obtain penalties or criminal sanctions for
violations. Enforcement procedures may
vary, depending on the specific requirements
of different environmental laws and related
regulatory requirements. Under CERCLA,
for example, the EPA will seek to require
potentially responsible parties to clean up a
Superfund site or pay for the cleanup [see
Cost Recovery].
Erosion: The wearing away of land surface
by wind or water. Erosion occurs naturally
from weather or surface runoff, but can be
intensified by such land-related practices as
farming, residential or industrial develop-
ment, road building, or timber-cutting. Ero-
sion may spread surface contamination to off-
site locations.
Estuary (estuarine): Areas where fresh
water from rivers and salt water from
nearshore ocean waters are mixed. These
areas may include bays, mouths of rivers, salt
marshes, and lagoons. These water ecosys-
tems shelter and feed marine life, birds, and
wildlife.
Evaporation Ponds: Areas where sewage
sludge or other watery wastes are dumped and
allowed to dry out.
Feasibility Study: The analysis of the
potential cleanup alternatives for a site. The
feasibility study usually starts as soon as the
remedial investigation is underway; together,
they are commonly referred to as the RI/FS
[see Remedial Investigation].
Filtration: A treatment process for removing
solid (paniculate) matter from water by
passing the water through sand, activated
carbon, or a man-made filter. The process is
often used to remove particles that contain
contaminants.
Flood Plain: An area along a river, formed
from sediment deposited by floods. Flood
plains periodically are innundated by natural
floods, which can spread contamination.
Flue Gas: The air that is emitted from a
chimney after combustion in the burner
occurs. The gas can include nitrogen oxides,
carbon oxides, water vapor, sulfur oxides,
panicles, and many chemical pollutants.
Fly Ash: Non-combustible residue that
results from the combustion of flue gases. It
can include nitrogen oxides, carbon oxides,
water vapor, sulfur oxides, as well as many
other chemical pollutants.
French Drain System: A crushed rock drain
system constructed of perforated pipes, which
is used to drain and disperse wastewater.
Gasification (coal): The conversion of soft
coal into gas for use as a fuel.
Generator: A facility that emits pollutants
into the air or releases hazardous wastes into
water or soil.
Good Faith Offer: A voluntary offer, gener-
ally in response to a Special Notice letter,
made by a potentially responsible party,
consisting of a written proposal demonstrating
a potentially responsible party's qualifications
57
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GLOSSARY.
and willingness to perform a site study or
cleanup.
Groundwater: Underground water that fills
pores in soils or openings in rocks to the point
of saturation. In aquifers, groundwater occurs
in sufficient quantities for use as drinking and
irrigation water and other purposes.
Groundwater Quality Assessment: The
process of analyzing the chemical characteris-
tics of groundwater to determine whether any
hazardous materials exist.
Halogens: Reactive non-metals, such as
chlorine and bromine. Halogens are very
good oxidizing agents and, therefore, have
many industrial uses. They are rarely found
by themselves; however, many chemicals
such as polychlorinated biphenyls (PCBs),
some volatile organic compounds (VOCs),
and dioxin are reactive because of the pres-
ence of halogens.
Hazard Ranking System (HRS): The
principal screening tool used by the EPA to
evaluate relative risks to public health and the
environment associated with abandoned or
uncontrolled hazardous waste sites. The HRS
calculates a score based on the potential of
hazardous substances spreading from the site
through the air, surface water, or groundwater
and on other factors such as nearby popula-
tion. The HRS score is the primary factor in
deciding if the site should be on the NPL.
Hazardous Waste: By-products of society
that can pose a substantial present or potential
hazard to human health and the environment
when improperly managed. It possesses at
least one of four characteristics (ignitability,
corrosivity, reactivity, or toxicity), or appears
on special EPA lists.
Hot Spot: An area or vicinity of a site con-
taining exceptionally high levels of contami-
nation.
Hydrogeology: The geology of groundwater,
with particular emphasis on the chemistry and
movement of water.
Impoundment: A body of water or sludge
confined by a dam, dike, floodgate, or other
barrier.
Incineration: A group of treatment technolo-
gies involving destruction of waste by con-
trolled burning at high temperatures, e.g.,
burning sludge to reduce the remaining
residues to a non-burnable ash that can be
disposed of safely on land, in some waters, or
in underground locations.
Infiltration: The movement of water or other
liquid down through soil from precipitation
(rain or snow) or from application of waste-
water to the land surface.
Influent: Water, wastewater, or other liquid
flowing into a reservoir, basin, or treatment
plant.
Injection Well: A well into which waste
fluids are placed, under pressure, for purposes
of disposal.
Inorganic Chemicals: Chemical substances
of mineral origin, not of basic carbon struc-
ture.
Installation Restoration Program: The
specially funded program established in 1978
under which the Department of Defense has
been identifying and evaluating its hazardous
waste sites and controlling the migration of
hazardous contaminants from those sites.
Intake: The source from where a water
supply is drawn, such as from a river or water
body.
Interagency Agreement: A written agree-
ment between the EPA and a Federal agency
that has the lead for site cleanup activities,
58
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GLOSSARY
setting forth the roles and responsibilities of
the agencies for performing and overseeing
the activities. States often are parties to
interagency agreements.
Interim (Permit) Status: Conditions under
which hazardous waste treatment, storage,
and disposal facilities, that were operating
when regulations under the RCRA became
final in 1980, are temporarily allowed by the
EPA to continue to operate while awaiting
denial or issuance of a permanent permit. The
facility must comply with certain regulations
to maintain interim status.
Lagoon: A shallow pond or liquid waste
containment structure. Lagoons typically are
used for the storage of wastewaters, sludges,
liquid wastes, or spent nuclear fuel.
Landfarm: To apply waste to land and/or
incorporate waste into the surface soil, such
as fertilizer or soil conditioner. This practice
commonly is used for disposal of composted
wastes and sludges.
Landfill: A disposal facility where waste is
placed in or on land. Sanitary landfills are
disposal sites for non-hazardous solid wastes.
The waste is spread in layers, compacted to
the smallest practical volume, and covered
with soil at the end of each operating day.
Secure chemical landfills are disposal sites for
hazardous waste. They are designed to
minimize the chance of release of hazardous
substances into the environment [see Re-
source Conservation and Recovery Act].
Leachate [n]: The liquid that trickles
through or drains from waste, carrying soluble
components from the waste. Leach, Leach-
ing [v.t.]: The process by which soluble
chemical components are dissolved and
carried through soil by water or some other
percolating liquid.
Leachate Collection System: A system that
gathers liquid that has leaked into a landfill or
other waste disposal area and pumps it to the
surface for treatment.
Liner: A relatively impermeable barrier
designed to prevent leachate (waste residue)
from leaking from a landfill. Liner materials
include plastic and dense clay.
Long-term Remedial Phase: Distinct, often
incremental, steps that are taken to solve site
pollution problems. Depending on the com-
plexity, site cleanup activities can be sepa-
rated into several of these phases.
Marsh: A type of wetland that does not
contain peat moss deposits and is dominated
by vegetation. Marshes may be either fresh or
saltwater and tidal or non-tidal [see Wetland].
Migration: The movement of oil, gas,
contaminants, water, or other liquids through
porous and permeable soils or rock.
Mill Tailings: [See Mine Tailings].
Mine Tailings: A fine, sandy residue left
from mining operations. Tailings often
contain high concentrations of lead, uranium,
and arsenic or other heavy metals.
Mitigation: Actions taken to improve site
conditions by limiting, reducing, or control-
ling toxicity and contamination sources.
Modeling: A technique using a mathematical
or physical representation of a system or
theory that tests the effects that changes on
system components have on the overall
performance of the system.
Monitoring Wells: Special wells drilled at
specific locations within, or surrounding, a
hazardous waste site where groundwater can
be sampled at selected depths and studied to
obtain such information as the direction in
59
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GLOSSARY.
which groundwater flows and the types and
amounts of contaminants present.
National Priorities List (NPL): The EPA's
list of the most serious uncontrolled or aban-
doned hazardous waste sites identified for
possible long-term cleanup under Superfund.
The EPA is required to update the NPL at
least once a year.
Neutrals: Organic compounds that have a
relatively neutral pH, complex structure and,
due to their organic bases, are easily absorbed
into the environment. Naphthalene, pyrene,
and trichlorobenzene are examples of
neutrals.
Nitroaromatics: Common components of
explosive materials, which will explode if
activated by very high temperatures or pres-
sures; 2,4,6-Trinitrotoluene (TNT) is a
nitroaromatic.
Notice Letter: A General Notice Letter
notifies the parties potentially responsible for
site contamination of their possible liability.
A Special Notice Letter begins a 60-day
formal period of negotiation during which the
EPA is not allowed to start work at a site or
initiate enforcement actions against poten-
tially responsible parties, although the EPA
may undertake certain investigatory and
planning activities. The 60-day period may
be extended if the EPA receives a good faith
offer within that period.
On-Scene Coordinator (OSC): The
predesignated EPA, Coast Guard, or Depart-
ment of Defense official who coordinates and
directs Superfund removal actions or Clean
Water Act oil- or hazardous-spill corrective
actions.
Operation and Maintenance: Activities
conducted at a site after a cleanup action is
completed to ensure that the cleanup or
containment system is functioning properly.
Organic Chemicals/Compounds: Chemical
substances containing mainly carbon, hydro-
gen, and oxygen.
Outfall: The place where wastewater is
discharged into receiving waters.
Overpacking: Process used for isolating
large volumes of waste by jacketing or encap-
sulating waste to prevent further spread or
leakage of contaminating materials. Leaking
drums may be contained within oversized
barrels as an interim measure prior to removal
and final disposal.
Pentachlorophenol (PCP): A synthetic,
modified petrochemical that is used as a wood
preservative because of its toxicity to termites
and fungi. It is a common component of
creosotes and can cause cancer.
Perched (groundwater): Groundwater
separated from another underlying body of
groundwater by a confining layer, often clay
or rock.
Percolation: The downward flow or filtering
of water or other liquids through subsurface
rock or soil layers, usually continuing down-
ward to groundwater.
Petrochemicals: Chemical substances
produced from petroleum in refinery opera-
tions and as fuel oil residues. These include
fluoranthene, chrysene, mineral spirits, and
refined oils. Petrochemicals are the bases
from which volatile organic compounds
(VOCs), plastics, and many pesticides are
made. These chemical substances often are
toxic to humans and the environment.
Phenols: Organic compounds that are used
in plastics manufacturing and are by-products
of petroleum refining, tanning, textile, dye,
and resin manufacturing. Phenols are highly
poisonous.
60
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GLOSSARY
Physical Chemical Separation: The treat-
ment process of adding a chemical to a sub-
stance to separate the compounds for further
treatment or disposal.
Pilot Testing: A small-scale test of a pro-
posed treatment system in the field to deter-
mine its ability to clean up specific contami-
nants.
Plugging: The process of stopping the flow
of water, oil, or gas into or out of the ground
through a borehole or well penetrating the
ground.
Plume: A body of contaminated groundwater
flowing from a specific source. The move-
ment of the groundwater is influenced by such
factors as local groundwater flow patterns, the
character of the aquifer in which groundwater
is contained, and the density of contaminants
[see Migration].
Pollution: Generally, the presence of matter
or energy whose nature, location, or quantity
produces undesired health or environmental
effects.
Polycyclic Aromatic Hydrocarbons or
Polyaromatic Hydrocarbons (PAHs):
PAHs, such as pyrene, are a group of highly
reactive organic compounds found in motor
oil. They are a common component of creo-
sotes and can cause cancer.
Polvchlorinated Biphenyls (PCBs): A
group of toxic chemicals used for a variety of
purposes including electrical applications,
carbonless copy paper, adhesives, hydraulic
fluids, microscope immersion oils, and caulk-
ing compounds. PCBs also are produced in
certain combustion processes. PCBs are
extremely persistent in the environment
because they are very stable, non-reactive,
and highly heat resistant Chronic exposure
to PCBs is believed to cause liver damage. It
also is known to bioaccumulate in fatty
tissues. PCB use and sale was banned in
1979 with the passage of the Toxic Sub-
stances Control ACL
Polynuclear Aromatic Hydrocarbons
(PNAs): PNAs, such as naphthalene, and
biphenyls, are a group of highly reactive
organic compounds that are a common com-
ponent of creosotes, which can be carcino-
genic.
Polyvinyl Chloride (PVC): A plastic made
from the gaseous substance vinyl chloride.
PVC is used to make pipes, records, raincoats,
and floor tiles. Health risks from high con-
centrations of vinyl chloride include liver
cancer and lung cancer, as well as cancer of
the lymphatic and nervous systems.
Potable Water: Water that is safe for drink-
ing and cooking.
Potentially Responsible Parties (PRPs):
Parties, including owners, who may have
contributed to the contamination at a Su-
perfund site and may be liable for costs of
response actions. Parties are considered PRPs
until they admit liability or a court makes a
determination of liability. PRPs may sign a
Consent Decree or Administrative Order on
Consent to participate in site cleanup activity
without admitting liability.
Precipitation: The removal of solids from
liquid waste so that the solid and liquid
portions can be disposed of safely; the re-
moval of particles from airborne emissions.
Electrochemical precipitation is the use of an
anode or cathode to remove the hazardous
chemicals. Chemical precipitation involves
the addition of some substance to cause the
solid portion to separate.
Preliminary Assessment: The process of
collecting and reviewing available informa-
tion about a known or suspected waste site or
release to determine if a threat or potential
threat exists.
61
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GLOSSARY.
Pump and Treat: A groundwater cleanup
technique involving the extracting of contami-
nated groundwater from the subsurface and
the removal of contaminants, using one of
several treatment technologies.
Radionuclides: Elements, including radium
and uranium-235 and -238, which break down
and produce radioactive substances due to
their unstable atomic structure. Some are
man-made, and others are naturally occurring
in the environment. Radon, the gaseous form
of radium, decays to form alpha particle
radiation, which cannot be absorbed through
skin. However, it can be inhaled, which
allows alpha particles to affect unprotected
tissues directly and thus cause cancer. Radia-
tion also occurs naturally through the break-
down of granite stones.
RCRA: [See Resource Conservation and
Recovery Act].
Recharge Area: A land area where rainwater
saturates the ground and soaks through the
earth to reach an aquifer.
Record of Decision (ROD): A public docu-
ment that explains which cleanup
alternative(s) will be used to clean up sites
listed on the NPL. It is based on information
generated during the remedial investigation
and feasibility study and consideration of
public comments and community concerns.
Recovery Wells: Wells used to withdraw
contaminants or contaminated groundwater.
Recycle: The process of minimizing waste
generation by recovering usable products that
might otherwise become waste.
Remedial Action (RA): The actual construc-
tion or implementation phase of a Superfund
site cleanup following the remedial design
[see Cleanup].
Remedial Design: A phase of site cleanup,
where engineers design the technical specifi-
cations for cleanup remedies and technolo-
gies.
Remedial Investigation: An in-depth study
designed to gather the data necessary to
determine the nature and extent of contami-
nation at a Superfund site, establish the
criteria for cleaning up the site, identify the
preliminary alternatives for cleanup actions,
and support the technical and cost analyses of
the alternatives. The remedial investigation
is usually done with the feasibility study.
Together they are customarily referred to as
the RI/FS [see Feasibility Study].
Remedial Project Manager (RPM): The
EPA or State official responsible for oversee-
ing cleanup actions at a site.
Remedy Selection: The selection of the
final cleanup strategy for the site. At the few
sites where the EPA has determined that
initial response actions have eliminated site
contamination, or that any remaining con-
tamination will be naturally dispersed with-
out further cleanup activities, a "No Action"
remedy is selected [see Record of Decision].
Removal Action: Short-term immediate
actions taken to address releases of hazardous
substances [see Cleanup].
Residual: The amount of a pollutant remain-
ing in the environment after a natural or
technological process has taken place, e.g.,
the sludge remaining after initial wastewater
treatment, or particulates remaining in air
after the air passes through a scrubbing, or
other, process.
Resource Conservation and Recovery Act
(RCRA): A Federal law that established a
regulatory system to track hazardous sub-
stances from the time of generation to dis-
posal. The law requires safe and secure
62
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GLOSSARY
procedures to be used in treating, transport-
ing, storing, and disposing of hazardous
substances. RCRA is designed to prevent
new, uncontrolled hazardous waste sites.
Retention Pond: A small body of liquid
used for disposing of wastes and containing
overflow from production facilities. Some-
times retention ponds are used to expand the
capacity of such structures as lagoons to store
waste.
Riparian Habitat: Areas adjacent to rivers
and streams that have a high density, diver-
sity, and productivity of plant and animal
species relative to nearby uplands.
Runoff: The discharge of water over land
into surface water. It can carry pollutants
from the air and land and spread contamina-
tion from its source.
Scrubber: An air pollution device that uses a
spray of water or reactant or a dry process to
trap pollutants in emissions.
Sediment: The layer of soil, sand, and
minerals at the bottom of surface waters, such
as streams, lakes, and rivers, that absorbs
contaminants.
Seeps: Specific points where releases of
liquid (usually leachate) form from waste
disposal areas, particularly along the lower
edges of landfills.
Seepage Pits: A hole, shaft, or cavity in the
ground used for storage of liquids, usually in
the form of leachate, from waste disposal
areas. The liquid gradually leaves the pit by
moving through the surrounding soil.
Septage: Residue remaining in a septic tank
after the treatment process.
Sinkhole: A hollow depression in the land
surface in which drainage collects; associated
with underground caves and passages that
facilitate the movement of liquids.
Site Characterization: The technical pro-
cess used to evaluate the nature and extent of
environmental contamination, which is
necessary for choosing and designing cleanup
measures and monitoring their effectiveness.
Site Inspection: The collection of informa-
tion from a hazardous waste site to determine
the extent and severity of hazards posed by
the site. It follows, and is more extensive
than, a preliminary assessment. The purpose
is to gather information necessary to score the
site, using the Hazard Ranking System, and to
determine if the site presents an immediate
threat that requires a prompt removal action.
Slag: The fused refuse or dross separated
from a metal in the process of smelting.
Sludge: Semi-solid residues from industrial
or water treatment processes that may be
contaminated with hazardous materials.
Slurry Wall: Barriers used to contain the
flow of contaminated groundwater or subsur-
face liquids. Slurry walls are constructed by
digging a trench around a contaminated area
and filling the trench with an impermeable
material that prevents water from passing
through it. The groundwater or contaminated
liquids trapped within the area surrounded by
the slurry wall can be extracted and treated.
Smelter: A facility that melts or fuses ore,
often with an accompanying chemical change,
to separate the metal. Emissions from smelt-
ers are known to cause pollution.
Soil Gas: Gaseous elements and compounds
that occur in the small spaces between par-
ticles of soil. Such gases can move through
63
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GLOSSARY.
or leave the soil or rock, depending on
changes in pressure.
Soil Vapor Extraction: A treatment process
that uses vacuum wells to remove hazardous
gases from soil.
Soil Washing: A water-based process for
mechanically scrubbing soils in-place to
remove undesirable materials. There are two
approaches: dissolving or suspending them in
the wash solution for later treatment by
conventional methods, and concentrating
them into a smaller volume of soil through
simple particle size separation techniques [see
Solvent Extraction].
Stabilization: The process of changing an
active substance into inert, harmless material,
or physical activities at a site that act to limit
the further spread of contamination without
actual reduction of toxicity.
Solidification/Stabilization: A chemical or
physical reduction of the mobility of hazard-
ous constituents. Mobility is reduced through
the binding of hazardous constituents into a
solid mass with low permeability and resis-
tance to leaching.
Solvent: A substance capable of dissolving
another substance to form a solution. The
primary uses of industrial solvents are as
cleaners for degreasing, in paints, and in
Pharmaceuticals. Many solvents are flam-
mable and toxic to varying degrees.
Solvent Extraction: A means of separating
hazardous contaminants from soils, sludges,
and sediment, thereby reducing the volume of
the hazardous waste that must be treated. It
generally is used as one in a series of unit
operations. An organic chemical is used to
dissolve contaminants as opposed to water-
based compounds, which usually are used in
soil washing.
Sorption: The action of soaking up or at-
tracting substances. It is used in many pollu-
tion control systems.
Stillbottom: Residues left over from the
process of recovering spent solvents.
Stripping: A process used to remove volatile
contaminants from a substance [see Air
Stripping].
Sumps: A pit or tank that catches liquid
runoff for drainage or disposal.
Superfund: The program operated under the
legislative authority of the CERCLA and
Superfund Amendments and Reauthorization
Act (SARA) to update and improve environ-
mental laws. The program has the authority
to respond directly to releases or threatened
releases of hazardous substances that may
endanger public health, welfare, or the envi-
ronment. The "Superfund" is a trust fund that
finances cleanup actions at hazardous waste
sites.
Surge Tanks: A holding structure used to
absorb irregularities in flow of liquids, includ-
ing liquid waste materials.
Swamp: A type of wetland that is dominated
by woody vegetation and does not accumulate
peat moss deposits. Swamps may be fresh or
saltwater and tidal or non-tidal [see Wet-
lands].
Thermal Treatment: The use of heat to
remove or destroy contaminants from soil.
Treatability Studies: Testing a treatment
method on contaminated groundwater, soil,
etc., to determine whether and how well the
method will work.
Trichloroethylene (TCE): A stable, color-
less liquid with a low boiling point. TCE has
many industrial applications, including use as
64
-------
GLOSSARY
a solvent and as a metal degreasing agent.
TCE may be toxic to people when inhaled,
ingested, or through skin contact and can
damage vital organs, especially the liver [see
Volatile Organic Compounds].
Unilateral [Administrative] Order: [see
Administrative Order].
Upgradient: An upward hydrologic slope;
demarks areas that are higher than contami-
nated areas and, therefore, are not prone to
contamination by the movement of polluted
groundwater.
Vacuum Extraction: A technology used to
remove volatile organic compounds (VOCs)
from soils. Vacuum pumps are connected to a
series of wells drilled to just above the water
table. The wells are sealed tightly at the soil
surface, and the vacuum established in the
soil draws VOC-contaminated air from the
soil pores into the well, as fresh air is drawn
down from the surface of the soil.
Vegetated Soil Cap: A cap constructed with
graded soils and seed for vegetative growth,
to prevent erosion [see Cap].
Vitrification: The process of electrically
melting wastes and soils or sludges to bind
the waste in a glassy, solid material more
durable than granite or marble and resistant to
leaching.
Volatile Organic Compounds (VOCs):
VOCs are manufactured as secondary petro-
chemicals. They include light alcohols,
acetone, trichloroethylene, perchloroethylene,
dichloroethylene, benzene, vinyl chloride,
toluene, and methylene chloride. These
potentially toxic chemicals are used as sol-
vents, degreasers, paints, thinners, and fuels.
Because of their volatile nature, they readily
evaporate into the air, increasing the potential
exposure to humans. Due to their low water
solubility, environmental persistence, and
widespread industrial use, they are commonly
found in soil and groundwater.
Waste Treatment Plant: A facility that uses
a series of tanks, screens, filters, and other
treatment processes to remove pollutants from
water.
Wastewater: The spent or used water from
individual homes or industries.
Watershed: The land area that drains into a
stream or other water body.
Water Table: The upper surface of the
groundwater.
Weir: A barrier to divert water or other
liquids.
Wetland: An area that is regularly saturated
by surface or groundwater and, under normal
circumstances, is capable of supporting
vegetation typically adapted for life in satu-
rated soil conditions. Wetlands are critical to
sustaining many species of fish and wildlife.
Wetlands generally include swamps, marshes,
and bogs. Wetlands may be either coastal or
inland. Coastal wetlands have salt or brackish
(a mixture of salt and fresh) water, and most
have tides, while inland wetlands are non-
tidal and freshwater. Coastal wetlands are an
integral component of estuaries.
Wildlife Refuge: An area designated for the
protection of wild animals, within which
hunting and fishing are either prohibited or
strictly controlled.
65
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APPENDIX B
Information
Repositories
for
NPL Sites
in Arizona
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