United States
Environmental Protection
Agency
Solid Waste And
Emergency Response
(OS-240)
EPA/540/8-91/063
September 1991
PB92-963238
N-/EPA National
Priorities
List Sites:
WYOMING
Printed on Recycled Paper
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Publication #9200.5-749A
September 1991
NATIONAL PRIORITIES LIST SITES:
Wyoming
U.S. Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jackson Beiiiev::, j, 12th floor
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
Superfund:
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 Wyoming 17
The NPL Report:
Progress to Date 19
The NPL Fact Sheets:
Summary of Site Activities 21
Appendix A: Glossary:
Terms Used in the Fact Sheets 29
Appendix B: Repositories of
Site Information 45
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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 HRS 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^Description
EPA REGION XX
CONGRESSIONAL DIST XX
COUNTY NAME
LOCATION
Other Name*:
NPL Listing History
Pint
hreats and Contaminants
Cleanup Approach
Response Action Status
Site Facts:,
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
Wyoming
Wyoming is a mountainous state lying in the high western plateaus of the Great Plains within
EPA Region 8. Region 8 includes six northern central states extending from the central plains to
the Rocky Mountains. Wyoming covers 97,809 square miles consisting of the Great Plains, the
foothills of the Rocky Mountains, and the Continental Divide. Currently with the smallest U.S.
population, according to the 1990 Census, Wyoming experienced a 3.4 percent decrease in
population since 1980 and has approximately 453,600 residents. Principal state industries
include mineral extraction, tourism and recreation, and agriculture. Wyoming manufacturing
produces refined petroleum products, foods, wood products, and stone, clay, and glass goods.
How Many NPL Sites
Are in the State of Wyoming?
Proposed
Final
Deleted
0
3
Q
3
Where Are the NPL Sites Located?
Congressional District 1
3 sites
What Type of Sites are on the NPL
in the State of Wyoming?
# of sites
1
1
1
type of sites
Petroleum Refining & Related Industry
Federal Facility
Lumber & Wood Treatment
17
April 1991
-------
NPL SITES
How Are Sites Contaminated and What Are the Principal* Chemicals?
3-
Q>
S52
i*.
o
1 --
GW Soil SW Sed
Contamination Area
Groundwater: Volatile organic
compounds (VOCs), creosotes (organ-
ics), and petrochemicals.
Soil: Volatile organic compounds
(VOCs), heavy metals (inorganics),
dioxins, creosotes (organics), and
petrochemicals.
Surface Water and Sediments:
Volatile organic compounds (VOCs),
dioxins, and creosotes (organics).
Appear at 33% or more sites
Where Are the Sites in the Superfund Cleanup Process?1
1
Site
with I
Studies
Underway
Sites
with
Remedy
Selected
1
Site
with
Remedy
Design
1
Site
with
Cleanup
Ongoing
Sites
with
Construction
Complete
Deleted
Sites
In addition to activities described above, initial actions have been taken at 2 sites as interim
cleanup measures.
'Cleanup status reflects phases of site activities rather than administrative accomplishments.
April 1991
18
-------
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.
19
April 1991
-------
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THE NPL FACT SHEETS
Summary
of Site
Activities
EPA REGION 8
21
ApriM991
-------
Who Do I Call with Questions?
The following pages describe each NPL site in Wyoming, providing specific
information on threats and contaminants, cleanup activities, and environmen-
tal progress. Should you have questions, please call EPA's Region 8 Office
in Denver, Colorado or one of the other offices, listed below:
EPA Region 8 Superfund Community Relations Office
EPA Region 8 Superfund Office
EPA Superfund Hotline
EPA Headquarters Public Information Center
Wyoming Superfund Office
(303)294-1100
(303)293-1720
(800) 424-9346
(202) 260-2080
(307)777-7781
April 1991
22
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BAXTER/UNIOJS^
PACIFIC
TIE TREATING
WYOMING
EPA ID#WYD0611 12470
EPA REGION 8
CONGRESSIONAL DIST. 01
Albany County
1 3/4 miles southwest of Laramie
Site Description
The Union Pacific Railroad, or its contractor, treated railroad ties at the Baxter/Union Pacific Tie
Treating site between 1886 and 1983, using various chemicals including zinc chloride, a mixture of
creosote oil and an asphalt-based oil, and pentachlorophenol (PCP). During the operation's first 70
years, workers disposed of process wastes in the Laramie waste collection ponds. Contamination
outside these ponds was discovered in 1981 during groundwater monitoring required by the EPA.
Approximately 140 acres of the property's 700 acres currently are polluted with oils and wood
treating chemicals. The railroad voluntarily ceased operations at the site in 1983. The City of
Laramie has a population of 24,000. The public water supply for Laramie is not connected to the
site; the city uses a reservoir fed by the Laramie River several miles upriver. Contaminated water
beneath the site is not used for drinking, and domestic private wells near the site were sampled and
found clean.
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, soil, and sediments contained numerous polycyclic aromatic hydrocarbons
(PAHs) including PCP. PCP levels were shown to be higher downgradient, indicating
movement of contaminants from the site. The public drinking supply is protected, as it is
drawn from above the contamination area; however, direct contact with site
contaminants is a possible health threat.
23
ApriM991
-------
Cleanup Approach
This site is being addressed in two long-term remedial phases focusing on source control and cleanup
of the contaminated groundwater and soil.
Response Action Status
Source Control: The EPA selected an interim remedy to control the source of
contamination and to address groundwater cleanup in 1986. The remedy features an
isolation system designed to keep contaminated groundwater and soil from moving off
site while more permanent remedies are planned. This remedy includes: (1) realigning the Laramie
River Channel 150 feet farther west from the site to reduce the chance of contamination; (2)
constructing a slurry wall through the soil and bedrock around contaminated areas; (3) draining and
pumping groundwater against its natural flow to keep it from seeping off site and through the slurry
wall; (4) treating withdrawn groundwater with activated carbon to decontaminate it; (5) discharging
this cleaned water into the Laramie River, under State and Federal permits; and (6) monitoring the
groundwater to track the effectiveness of the system. All cleanup activities have been completed.
Operation and maintenance, as well as monitoring of the remedies are taking place to ensure that
cleanup actions continue to be effective.
Groundwater and Soil: In 1990, Union Pacific began treatability studies, under EPA
monitoring, to determine if bioremediation of contaminated soil and groundwater would
be an effective remedy. Other alternatives also are being evaluated. These studies are
scheduled to be completed in 1992.
Environmental Progress
The cleanup actions to contain the source of contamination have been completed at the Baxter/
Union Pacific Tie Treating site. Monitoring to ensure the interim remedies' effectiveness is
continuing while groundwater and soil treatability studies are underway.
April 1991 24 BAXTER/UNION
M PACIFIC TIE TREATING
-------
F.E. WARREMAIH
FORCE 3A3E
WYOMING
EPAID#WY5571£24t?S
Site Description
EPA REGION 8
CONGRESSIONAL DIST. 01
Laramie County
Cheyenne
The 5,866-acre F.E. Warren Air Force Base site initially began as a U.S. Army cavalry outpost in
1867 and has since served a number of military functions. In 1947, control of the facility was
transferred to the U.S. Air Force, and it became a Strategic Air Command base in 1958. Waste
generation at the facility has consisted primarily of spent solvents from equipment cleaning and
various maintenance operations. The Air Force also maintained an acid well used for spent battery
acid disposal. While five landfills are located at the facility and hold various wastes, only one
landfill is presently in operation. Two fire protection areas involved extensive use of various fuels
and combustible materials for fire training exercises. Initially, 25 areas were identified where
hazardous materials might have been used, stored, treated, or disposed. Agricultural lands and
industrial developments surround the base. Approximately 2,400 people draw drinking water from
private deep aquifer wells. These wells lie within 3 miles upgradient of hazardous substances on the
base.
Site Responsibility: This site is being addressed through
Federal actions.
NPL LISTING HISTORY
Proposed Date: 07/14/89
Final Date: 02/21/90
Threats and Contaminants
Contamination from trichloroethylene (TCE), gasoline, oils, hydraulic fluid,
ethylene glycol, and battery acid was found in shallow groundwater zones and
soils. TCE was found in surface water samples at various locations.
Contaminated groundwater, discharging to surface waters (Crow and Diamond
Creeks), is believed to be the TCE contamination source. Direct contact with
contaminated groundwater, surface water, and soil may adversely affect human
health.
25
April 1991
-------
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 1986, the Air Force removed an acid disposal well system and an
unknown amount of contaminated soil. In 1989, the Air Force removed a building drain
sump, 3,000 gallons of contaminated liquid, 300 gallons of contaminated sludge, and
300,000 pounds of contaminated soil from an area known as Spill Site 7.
Entire Site: A Federal Facility Agreement currently is being negotiated and is expected
to be signed in 1991 that will define EPA and State involvement in future site
investigations and cleanup actions. The Agreement will divide the site into seven cleanup
stages. These consist of shallow and deep groundwater zones (two separate stages), the acid dry
well area, the landfills, the fire training areas, the base firing range, and a munitions detonation area.
The Agreement also will require further investigations at the site and will provide a timeframe for
submittal of needed site documents. A draft report from a site investigation was completed and
reviewed by the EPA and the State. Further investigations are needed to determine contamination in
deeper groundwater zones. Also, the extent of potential or suspected surface sources needs to be
further identified. The Air Force currently is preparing plans to conduct further site investigations at
surface sources and to determine deeper groundwater contamination.
Site Facts: F.E. Warren Air Force Base is participating in the Installation Restoration Program
(IRP), a specially funded program developed in 1978 by the Department of Defense (DoD) to
identify, investigate, and control the migration of hazardous contaminants at military and other DoD
facilities.
Environmental Progress
The initial actions to remove contaminated soil, sludge, and liquids have greatly reduced the
potential for exposure to hazardous substances at the F.E. Warren Air Force Base site while
further studies are taking place and cleanup activities are being planned.
April 1991 26 F.E. WARREN AIR FORCE BASE
-------
MYSTERY
ROAD/HIG
WYOMING
EPA ID#WYD9815460
Site Description
EPA REGION 8
CONGRESSIONAL DIST. 01
Matrons County
1 mile east of Evansville
Other Names:
Brookhurst
The 450-acre Mystery Bridge Road/Highway 20 site is located adjacent to an oil refinery and other
industries in the Brookhurst and Mystery Bridge Subdivisions. One area of the site, the KN Energy
location, served as a natural gas processing operation. There was an unlined waste pond on this area
that was used from 1965 until 1984. Another area of the site operated as an oil field service and
includes a former toluene storage area, a truck wash drain system, and an abandoned sump. Studies
started in 1986 in response to citizen complaints identified the presence of volatile organic
compounds (VOCs) in area wells and drinking water. The Brookhurst Subdivision was developed
during the mid-1970s and consists of about 100 homes, 90 of which are affected by chlorinated
hydrocarbon contamination of drinking water wells. Domestic wells in the area tap into shallow
groundwater. In 1988, a contaminated ground water plume moving from the Little America Refining
Co. (LARCO), an area adjacent to the Brookhurst property, was identified.
Site Responsibility:
This site is being addressed through
Federal and potentially responsible
parties' actions.
NPL LISTING HISTORY
Proposed Date: 06/24/88
Final Date: 08/30/90
Threats and Contaminants
Groundwater and soil are contaminated with VOCs, petroleum products, and other
hazardous substances. Drinking of or direct contact with contaminated groundwater are
the greatest health threats to Brookhurst residents.
Cleanup Approach
This site is being addressed in three stages: immediate actions and two long-term remedial phase
focusing on cleanup of the groundwater and remaining subsurface contamination.
27
April 1991
-------
Response Action Status
Immediate Actions: In 1987, the EPA provided bottled water to 45 residences as an
interim measure until the water distribution system was installed later in the year.
Hookups to the drinking water system between Evansville and Brookhurst were
completed in 1988. A sedimentation pond and intake structure modifications were constructed at the
Evansville water treatment plant In 1988, KN Energy removed 35 drums of liquid and sludge from
the flare pit area and sent the drums off site to a disposal facility. KN Energy also installed a pump
and treat system and soil vapor extraction system to eliminate the release of contaminants into the
groundwater. In 1988, Dow Chemical Company and Dowell-Schlumberger removed 420 cubic
yards of contaminated soil from the facility and installed a soil vapor extraction system to remove
remaining contaminants in the soil.
Groundwater: In 1990, Dow, Dowell-Schlumberger, and KN Energy completed an
investigation into the nature and extent of contamination at the site. Work performed
during the investigation, including the installation of 13 monitoring wells, soil vapor
analysis, surface and sediment sampling, and collection of water samples from monitoring wells,
was completed in 1989. Three containment plumes were identified in the groundwater. In 1990, the
EPA selected a remedy to cleanup the groundwater, which includes: pumping of the first plume,
which contains benzene, xylenes and toluene and treatment using air stripping; and limited pumping
of the second plume, which contains VOCs, and treatment using air stripping and reinjection of
clean water into the aquifer. The third plume will be addressed under the Resource Conservation
and Recovery Act (RCRA). Design of the selected remedy began in 1991.
Subsurface Contamination: An investigation into the nature and extent of any
remaining subsurface contamination and potential impacts on groundwater will begin in
mid-1991.
Site Facts: In 1988, the EPA issued Consent Orders to three potentially responsible parties, KN
Energy, Inc., Dow Chemical Co., and Dowell Schlumberger, Inc., ordering them to clean up two
separate suspected sources of groundwater contamination and site contamination. In 1988, the EPA
issued an Administrative Order to LARCO, another potentially responsible party, requiring the
company to investigate the contamination plume migrating toward the Brookhurst subdivision and
to perform cleanup actions on its property and off site.
Environmental Progress
The immediate actions to provide bottled water until safe municipal water supplies could be
provided and to remove accessible surface contaminants have greatly reduced the potential for
exposure to hazardous substances at the Mystery Bridge Road/Highway 20 site while studies and
cleanup activities are being completed.
April 1991 28 MYSTERY BRIDGE ROAD/HIGHWAY 20
-------
APPENDIX A
Glossary:
Terms Used
in the
Fact Sheets
29
-------
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.
31
-------
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
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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.
33
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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
downgradient 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.
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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,
particles, 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
35
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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,
36
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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
37
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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.
38
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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.
Polychlorinated 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 Act.
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
Superfund 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.
39
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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 panicle
radiation, which cannot be absorbed through
skin. However, it can be inhaled, which
allows alpha panicles 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
40
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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
41
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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
42
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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.
43
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APPENDIX B
Repositories
for
NPL Sites
in Wyoming
45
-------
of Wyoming
V^r
0)
+^
0
+-
(75
^^i
O.
O
H-
(/)
0
"L
O
nformation Reposil
"
/ities. Some sites may have more than one reposiu
te will be on file at these repositories. The quanl
;ss for each site and may include some or all of
heets detailing activities at sites, documents relat:
r documents pertaining to site activities.
£ '3 & - S
o « g> o -S
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S £ S § -S
c/1 S » O -
epositories are established for all NPL site
cation, however, the primary site repositi
\d nature of the documentation found in
blowing: community relations plans, ann
> the selection of cleanup remedies, press
eg 2 3 "
.22
Eight Street, Laran
5
3
&
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blic Library, 31
£
P«
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3
>,
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n
B AXTERAJNION PACIFIC TIE TREATIN*
s
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