&EPA
United States
Environmental Protection
Agency
Solid Waste And
Emergency Response
(5102G)
EPA/540/R-93/008
December 1992
PB93-963209
SUPERFUND:
Progress at
National
Priority
List Sites
DELAWARE
1992 UPDATE
Printed on Recycled Papt;r
-------
Publication #9200.5-7098
December 1992
NATIONAL PRIORITIES LIST SITES:
Delaware
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Office of Emergency & Remedial Response
Office of Program Management
Washington, DC 20460 _ . ..nn .opnn.
U.S. Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jackson Boulevard, 12th Floor
Chicago, 1L 60604-3590
-------
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) 486-4650
The complete set of the 49 State reports may be ordered as PB93-963250.
-------
TABLE OF CONTENTS
INTRODUCTION
A Brief Overview of Superfimd v
Streamlining Superfund: The Superfund Accelerated Cleanup Model ix
How Superfund Works x
THE VOLUME
How to Use the State Book xi
A SUMMARY OF THE STATE PROGRAM
.XV
THE NPL REPORT
Progress to Date xix
THE NPL FACT SHEETS i
THE GLOSSARY
Terms used in the NPL Book G-l
-------
INTRODUCTION
A BRIEF OVERVIEW OF SUPERFUND
During the second half of the Twentieth
Century, the environmental conse-
quences of more than 100 years of industrial-
ization in the United States became increas-
ingly clear. Authors such as Rachel Carson
wrote passionately about the often-hidden en-
vironmental effects of our modern society's
widespread use of chemicals and other haz-
ardous materials. Their audience was small at
first, but gradually their message spread.
Growing concern turned to action, as people
learned more about the environment and be-
gan to act on their knowledge
The 1970s saw environmental issues burst
onto the national scene and take hold in the
national consciousness. The first Earth Day
was observed in 1970, the year that the U.S.
Environmental Protection Agency (EPA) was
founded. By the end of the 1970s, Love Canal
in New York and the Valley of the Drums in
Kentucky had entered the popular lexicon as
synonyms for pollution and environmental
degradation.
Superfund Is Established
The industrialization that gave Americans the
world's highest standard of living also created
problems that only a national program could
address. By 1980, the U.S. Congress had
passed numerous environmental laws, imple-
mented by the EPA, but many serious hazard-
ous waste problems were slipping through the
cracks.
Responding to growing concern about public
health and environmental threats from uncon-
trolled releases of hazardous materials, the
U.S. Congress passed the Comprehensive En-
vironmental Response, Compensation, and
Liability Act (CERCLA). Popularly known as
Superfund, CERCLA had one seemingly
simple job—to uncover and clean up hazard-
ous materials spills and contaminated sites.
A Big Job
Few in Congress, the EPA, the environmen-
tal community, or the general public knew in
1980 just how big the nation's hazardous ma-
terials problem is. Almost everyone thought
that Superfund would be a short-lived pro-
gram requiring relatively few resources to
clean up at most a few hundred sites. They
were quite mistaken.
As the EPA set to work finding sites and
gauging their potential to harm people and
the environment, the number of sites grew.
Each discovery seemed to lead to another,
and today almost 36,000 hazardous waste
sites have been investigated as potential haz-
ardous waste sites. They are catalogued in
the EPA's computerized database, CERCLIS
(for the Comprehensive Environmental Re-
-------
INTRODUCTION
sponse, Compensation, and Liability Informa-
tion System).
The damage to public health and the environ-
ment that each site in CERCLIS might cause
is evaluated; many sites have been referred to
State and local governments for cleanup. The
EPA lists the nation's most serious hazardous
waste sites on the National Priorities List, or
NPL. (These Superfund sites are eligible for
federally-funded cleanup, but whenever pos-
sible the EPA makes polluters pay for the
contamination they helped create.) The NPL
now numbers 1,275 sites, with 50 to 100
added each year. By the end of the century,
the NPL may reach as many as 2,100 sites.
Superfund faces some of the most complex
pollution problems ever encountered by an
environmental program. Improperly stored or
disposed chemicals and the soil they contami-
nate are one concern. More difficult to correct
are the wetlands and bays, and the groundwa-
ter, lakes, and rivers often used for drinking
water that are contaminated by chemicals
spreading through the soil or mixing with
storm water runoff. Toxic vapors contaminate
the air at some sites, threatening the health of
people living and working near by.
Superfund aims to control immediate public
health and environmental threats by tackling
the worst problems at the worst sites first.
Wherever possible, Superfund officials use
innovative treatment techniques—-many de-
veloped or refined by the EPA—to correct
hazardous materials problems once and for
all. Many of the treatment techniques they use
did not exist when the program was created.
The EPA Administrator had challenged Su-
perfund to complete construction necessary
for cleanup work at 130 NPL sites by the end
of the 1992 federal fiscal year. By September
30, 1992, the end of fiscal year 1992, con-
struction had been completed at a total of 149
NPL sites. Superfund is well on its way of
meeting the Administrator's goal of complet-
ing construction at 200 NPL sites by the end
of fiscal year 1993, and 650 sites by the end
of fiscal year 2000.
Quick Cleanup at
Non-NPL Sites
Long-standing hazardous waste sites are not
Superfund's only concern. The EPA also re-
sponds to hazardous spills and other emergen-
cies, hauling away chemicals for proper treat-
ment or disposal. Superfund teams perform or
supervise responses at rail and motor vehicle
accidents, fires, and other emergencies in-
volving hazardous substances. They also
evacuate people living and working near by,
if necessary, and provide clean drinking water
to people whose own water is contaminated.
Removal crews also post warning signs and
take other precautions to keep people and ani-
mals away from hazardous substances.
Superfund employee prepares equipment for groundwater
treatment.
VI
-------
INTRODUCTION
Quick Cleanups, or Removals, are not limited
to emergencies. When cleanup crews at con-
taminated sites find hazardous substances that
immediately threaten people or the environ-
ment, they act right away to reduce the threat
or to remove the chemicals outright. As the
EPA implements the Superfund Accelerated
Cleanup Model (SACM), more and more sites
will undergo quick cleanups, and many of
these will be cleaned up completely without
ever being included on the NPL. (See
"Streamlining Superfund: The Superfund Ac-
celerated Cleanup Model.")
Some of Superfund's most significant gains in
public health and environmental protection
have been won by the removal program. As of
March 31, 1992, the Emergency Response
Superfund employee removing drums from a Superfund site.
Program had logged more than 2,300 removal
completions since Superfund was established.
The Public's Role
Superfund is unique among federal programs
in its commitment to citizen participation. Al-
though the EPA is responsible for determin-
ing how dangerous a site is and how best to
clean it up, the Agency relies on citizen input
as it makes these decisions.
Community residents are often invaluable
sources of information about a hazardous
waste site, its current and previous owners,
and the activities that took place there. Such
information can be crucial to experts evaluat-
ing a site and its potential dangers.
Residents also comment on EPA cleanup
plans by stating their concerns and prefer-
ences at public meetings and other forums and
in formal, written comments to Agency pro-
posals. The EPA takes these comments and
concerns seriously, and has modified many
proposals in response to local concerns. For,
ultimately, it is the community and its citizens
that will live with the results of the EPA's de-
cisions and actions; it is only fair that citizens
participate in the process.
A Commitment to
Communication
The Superfund program is very serious about
public outreach and communication. Com-
munity relations coordinators are assigned to
each NPL site to help the public understand
the potential hazards present, as well as the
cleanup alternatives. Local information re-
positories, such as libraries or other public
buildings, have been established near each
NPL site to ensure that the public has an op-
portunity to review all relevant information
and the proposed cleanup plans.
The individual State volumes contain sum-
mary fact sheets on NPL sites in each State
and territory. Together, the fact sheets provide
a concise report on site conditions and the
progress made toward site cleanups as of
March 1992. The EPA revises these volumes
periodically to provide an up-to-date record of
program activities. A glossary of key terms
relating to hazardous waste management and
Superfund site cleanup is provided at the back
of this book.
VII
-------
INTRODUCTION
Superfund is, of course, a public program, and
as such it belongs to everyone of us. This vol-
ume, along with other State volumes, com-
prises the EPA's report on Superfund
progress to the program's owners for the year
1992.
VIII
-------
INTRODUCTION
STREAMLINING SUPERFUND: THE SUPERFUND
ACCELERATED CLEANUP MODEL
Historically, critics and supporters alike
have measured Superfund's progress
by the number of hazardous waste sites de-
leted from the NPL. Although easy enough to
tally, this approach is too narrow. It misses
the major gains Superfund makes by reducing
major risks at the nation's worst hazardous
sites long before all clean-up work is done
and the site deleted. It also ignores the Re-
moval Program's contributions to meeting
Superfund's twin mandates of maximizing
public health and environmental protection.
Renewing Superfund's commitment to rapid
protection from hazardous materials, the EPA
is streamlining the program. The Superfund
Accelerated Cleanup Model, or SACM, will
take Early Actions, such as removing hazard-
ous wastes or contaminated materials, while
experts study the site. SACM also will com-
bine similar site studies to reduce the time re-
quired to evaluate a site and its threats to
people and the environment. This way, imme-
diate public health and environmental threats
will be addressed while long-term cleanups
are being planned.
Emergencies such as train derailments and
motor vehicle accidents will continue to be
handled expeditiously. Teams of highly
trained technicians will swing into action
right away, coordinating the cleanup and re-
moval of hazardous substances to ensure pub-
lic safety as quickly as possible.
Breaking With Tradition
The traditional Superfund process begins with
a lengthy phase of study and site assessment,
but SACM will save time by combining sepa-
rate, yet similar, activities. Each EPA Region
will form a Decision Team of site managers,
risk assessors, community relations coordina-
tors, lawyers, and other experts to monitor the
studies and quickly determine whether a site
requires Early Action (taking less than five
years), Long-term Action, or both.
While the site studies continue, the Decision
Team will begin the short-term work required
to correct immediate public health or environ-
mental threats from the site. Besides remov-
ing hazardous materials, Early Actions in-
clude taking precautions to keep contaminants
from moving off the site and restricting access
to the site. Early Actions could eliminate most
human risk from these sites, and Superfund
will further focus its public participation and
public information activities on site assess-
ment and Early Action.
Long-Term Solutions
While Early Actions can correct many hazard-
ous waste problems—and provide the bulk of
public health and environmental protection—
some contamination will take longer to cor-
rect. Cleanups of mining sites, wetlands, estu-
aries, and projects involving incineration of
contaminants or restoration of groundwater
can take far longer than the three to five years
envisioned for Early Actions. Under SACM,
these sites will be handled much as they are
now.
Also under SACM, the EPA will continue its
pursuit of potentially responsible parties who
may have caused or contributed to site con-
tamination. Expedited enforcement and
procedures for negotiating potentially respon-
sible party settlements will secure their par-
ticipation. Superfund personnel will continue
to oversee clean-up work performed by poten-
tially responsible parties.
IX
-------
INTRODUCTION
HOW SUPERFUND WORKS
Each Superfund site presents a different
set of complex problems. The same haz-
ardous materials and chemicals often con-
taminate many sites, but the details of each
site are different. Almost always, soil is con-
taminated with one or more chemicals. Their
vapors may taint the air over and around the
site. Contaminants may travel through the soil
and reach underground aquifers which may be
used for drinking water, or they may spread
over the site to contaminate streams, ponds,
and wetlands. The contaminating chemicals
may interact with each other, presenting even
more complicated cleanup problems.
Superfund's cleanup process is arduous and
exacting. It requires the best efforts of hun-
dreds of experts in science and engineering,
public health, administration and manage-
ment, law, and many other fields.
The average NPL site takes from seven to ten
years to work its way through the system,
from discovery to the start of long-term
cleanup. Actual cleanup work can take years,
decades if contaminated groundwater must
be treated. Of course, imminent threats to
public health or the environment are cor-
rected right away.
The diagram to the right presents a simplified
view of the cleanup process. The major steps
in the Superfund process are:
• Site discovery and investigation to iden-
tify contaminants and determine whether
emergency action is required;
• Emergency site work such as removing
contaminants for proper treatment or dis-
posal, and securing the site to keep people
and animals away, if warranted by condi-
tions at the site;
• Site evaluation to determine how people
living and working nearby, and the envi-
ronment, may be exposed to site contami-
nants;
• Detailed studies to determine whether con-
ditions are serious enough to add the site to
the National Priorities List of sites eligible
for federally funded cleanup under Super-
fund;
1 Selection, design, and implementation of a
cleanup plan, after a thorough review of
the most effective cleanup options, given
site conditions, contaminants present, and
their potential threat to public health or the
environment.
1 Follow-up to ensure that the cleanup work
done at the site continues to be effective
over the long term.
The Superfund Process
From the earliest stages, EPA investigators
work hard to identify those responsible for the
contamination. As their responsibility is es-
tablished, the EPA negotiates with these "re-
sponsible parties" to pay for cleaning up the
problem they helped create. This "enforce-
ment first" policy saves Superfund Trust Fund
monies for use in cleanups where the respon-
sible parties cannot be identified, or where
they are unable to fund cleanup work.
-------
THE VOLUME
How to Use the State Book
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 discovered and related threats
to public and ecological health ("Threats and
Contaminants"). "Cleanup Approach" pres-
ents 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 environment. The
summaries also pinpoint other actions, such as
legal efforts to involve polluters responsible
for site contamination and community con-
cerns.
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-
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.
XI
-------
THE VOLUME
NPL LISTING HISTORY
Provides the dates when the
site was Proposed, made Final,
and Deleted from the NPL.
SITE RESPONSIBILITY
Identifies the Federal, State,
and/or potentially responsible
parties taking responsibility
for cleanup actions at the site.
ENVIRONMENTAL
PROGRESS
Summarizes the actions to
reduce the threats to nearby
residents and the surrounding
environment and the progress
towards cleaning up the site.
SITE NAME
STATE
EPA ID# ABCOOOOOOO
Site Description
EPA REGION XX
COUNTY NAME
LOCATION
Other Names:
XXX XXXXX XXXXXXXXXXXX XXXXXX XXXXXXXXX XXXXXXXX XXXXXXXXXXXXX XXXX:
:xxx xxxxxxxxxx xxxx xxxxxxxx xxxx XX xxxxxxxxx xx xxxxxx xxxxxxx:
xxxxxxxxxxx xx xxxxxx xxxx xxxxx xxxx x xxx xx:
XXXXXXX XXX Jcxx!Rttl*J£fxxxx XXXXX XXXXXX XXXXXXXX xxxxxxxx xxxx XXXXXXXXXX XXXXX'
XXXXXXXXXXXX XX XXXXXXX XXX XXXXX x5x>ISJ{XX XXXXXX XX XXXX XXX XXXXX XXX XXXXX XXX xx:
Site Responsibility:
Threats and Contaminants
Response Action Status
Site Facts:
xxxxxxxxxxx
^^^JXXXX>
Environmental Progress
Site Repository
xxxxxx xxx xxxxx xxxxxxxxxxxx xxxxxx :
SITE REPOSITORY
Lists the location of the primary site repository. The site
repository may include community relations plans, public
meeting announcements and minutes, fact sheets, press
releases, and other site-related documents.
XII
-------
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.
XIII
-------
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 vicinity or underlying the site.
(Groundwater is often used as a drink-
ing 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 vicinity
of the site. (Examples include wet-
lands and coastal areas or critical
habitats.)
Icons in the Response
Action Status Section
Initial, Immediate, or Emergency
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.
XIV
-------
A SUMMARY OF THE STATE PROGRAM
xv
-------
Superfund Activities in
Delaware
The State of Delaware is located within EPA Region 3, which includes the
five mid-Atlantic States and the District of Columbia. The State covers 2,045
square miles. According to the 1990 Census, Delaware experienced a 12 per-
cent increase in population between 1980 and 1990, and is ranked forty-sixth in
U.S. population with approximately 666,200 residents.
The Delaware Hazardous Substances Cleanup Act of 1990 grants the State
the authority to compel polluters to conduct or pay for cleanup activities. If
the polluters are unable or unwilling to participate, the State is authorized to
conduct cleanup activities itself and then recover the cost of cleanup from
the polluters at a later time. Unless an emergency exists, the State must first
attempt to settle with the polluters before using any other enforcement authorities. If negotia-
tions fail to result in an agreement, the State has the authority to make polluters liable for actual
or potential damages regardless of fault or actual contribution to the hazardous conditions of the
site. The 1990 Act also established the Hazardous Substances Cleanup Fund to pay for site
cleanup activities conducted by the State, including emergency response activities, removals,
long-term cleanup actions, and the 10 percent contribution from the State required under the
Federal Superfund program. The State also uses fund money to make loans to nonprofit and
small business polluters who are willing to clean up a site. Public hearings are required to
inform the community of proposed settlement agreements and cleanup plans. Currently, 20 sites
in the State of Delaware have been listed as final on the NPL; one has been deleted. No new
sites have been proposed for listing in 1992.
The Department of Natural Resources and Environmental Control
implements the Superfund Program in the State of Delaware
Activities responsible for hazardous
waste contamination in the State of
Delaware include:
Other
Landfills
Coal Gasification/
Wood Production
and Treatment
Operations
Recycling
Facilities
Chemical
Production
Facilities
Manufacturing Facilities
Facts about the 21 NPL sites
in Delaware:
Immediate Actions (such as removing
hazardous substances or restricting
site access) were performed at 12
sites.
Eight sites endanger sensitive envi-
ronments.
Nineteen sites are located near resi-
dential areas.
XVII
March 1992
-------
DELAWARE
Most Sites Have Multiple Contaminants and
Contaminated Media:
Media Contaminated at Sites
Ground-
water
0 10 20 30 40 50 60 70 80 90 100
Percentage of Sites
Contaminants Found at Sites
Percentage of Sites
VOCs
Heavy Metals
Creosotes
PCBs
Plastics
Pesticides/Herbicides
90%
62%
24%
19%
10%
5%
The Potentially Responsible
Party Pays...
In the State of Delaware, potentially responsible
parties are paying for or conducting cleanup
activities at 17 sites.
For Further Information on NPL Sites and Hazardous
Waste Programs in the State of Delaware Please Contact:
& EPA Region 3 Environmental
Education and Outreach Branch
& National Response Center
B1 The Department of Natural
Resources and Environmental
Control: Division of Air and Waste
Management, Superfund Branch
"& EPA Region 3 Site Assessment
Branch
® EPA Superfund Hotline
For information concerning
community involvement
To report a hazardous
waste emergency
For information about the
State's responsibility in the
Superfund Program
For information about the
Regional Superfund Program
For information about the
Federal Superfund Program
(215) 597-9370
(800) 424-8802
(302) 323-4544
(215) 597-8229
(800) 424-9068
March 1992
XVIII
-------
THE NPL REPORT
PROGRESS TO DATE
The following Progress Report lists all
sites currently on, or deleted from, the
NPL and briefly summarizes the status of ac-
tivities for each site at the time this report was
prepared. The steps in the Superfund cleanup
process are arrayed across the top of the chart,
and each site's progress through these steps is
represented by an arrow C^) 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 ac-
complishments.
^> An arrow in the "Initial Response" cate-
gory indicates that an emergency
cleanup, immediate action, or initial ac-
tion has been completed or currently is
underway. Emergency or initial actions
are taken as an interim measure to pro-
vide immediate relief from exposure to
hazardous site conditions or to stabilize
a site to prevent further contamination.
O A final arrow in the "Site Studies" cat-
egory indicates that an investigation to
determine the nature and extent of the
contamination at the site currently is on-
going or planned.
O A final arrow in the "Remedy Selection"
category means that the EPA has se-
lected 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 Action" rem-
edy has been 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 specifica-
tions 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 cur-
rently are underway.
O A final arrow in the "Construction Com-
plete" category is used only when all
phases of the site cleanup plan have
been performed, and the EPA has deter-
mined 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 pro-
tect human health and the environment.
/ A check in the "Deleted" category indi-
cates 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.
XIX
-------
•o
0)
«
0)
a
S
.!»
73 a>
It
50
o
Q.D)
3 C
S°
Sg)
00
ft
ft ft ft
ft
ft ft ft
ft ft
ft
ft
la ft ft ft ft ft
CD
OCQ
ft ft
ft ft
ft ft
>
C
3
O
O
CO
Z
0)
to
ft
ft
ft
m
S
1
UH
PJ
CO
U
^
s
| ARMY CREEK LANDFILL
ft ft
ft ft
ft ft
o r-
Os go
O ""^
eg. R
73 73
S S
PH PH
Z, Z
a a
8
CHEM-SOLV, INC.
COKER'S SANITATION SERVI
LANDFILLS
ft ft
ft ft
ft ft
m ro
as. 20
R R
S S
1 1
PH PH
PL) tU
^ |=j
U O
^ ^
g§
r Tt
DELAWARE CITY PVC PLAN!
DELAWARE SAND & GRAVEI
LANDFILL
ft
ft ft
ft
O> O"\
go go
2 S
r*? O
0 ~
1 1
PH PH
S 25
s@
DOVER AIR FORCE BASE
DOVER GAS LIGHT CO.
ft
ft ft
0 vo
gs_ go
€ R
ts vo
0 O
1 1
UH PU
PJ Pn1
CO CO
u u
^ fe
PJ UJ
fe
Q
<;
SH
E.I. DU PONT DeNEMOURS & <
(NEWPORT PIGMENT PLAN
HALBY CHEMICAL CO.
ft
ft ft ft
ft
ro O O
go Os os
0 ° °
S 0 0
111
PH PL, PH
W Ul
CO CO
U , U
^>- ^>-
sis
P
s
C
c/3 I> Z
!~) LxJ UU
Eo Z 2
^
SUSSEX COUNTY LANDFILL )
TYBOUTS CORNER LANDFILI
TYLER REFRIGERATION PIT
ft
ft
^
go
R
1
PH
g
n
WILDCAT LANDFILL
March 1992
xx
-------
CD
3
C
O
o,
¥
CO
JS
o
o
M—
o
0)
CO
0)
0)
e
o
oU
u
JJ S
UO
CO
Q.
CO
JI)
O
CO
-Mi
1
fe
2
D>
O
March 1992
-------
ARMY CREEK
LANDFILL
DELAWARE
EPA ID# DED980494496
Site Description
EPA REGION 3
New Castle County
2 miles southwest of New Castle
Other Names:
Llangollen Landfill
Delaware Sand & Gravel
Llangollen Army Creek Landfills
The Army Creek Landfill site occupies approximately 60 acres. It was used as a landfill for
municipal and industrial wastes from 1960 to 1968. During that 8-year period, about 2 million
cubic yards of refuse were landfilled. The site previously was used as a sand and gravel
quarry. Approximately 30 percent of the waste lies below the seasonal high water table.
Army Creek, which forms the southern and eastern borders of the site, flows into the
Delaware River about 1 mile east of the site. Groundwater contamination was discovered in
a nearby residential well in 1972. After studies were conducted by New Castle County, which
identified alcohols and acidic compounds in leachate, recovery wells were installed to prevent
the movement of groundwater toward public water supply wells. The water pumped out of
these wells currently is discharged untreated to Army Creek and Army Pond. Approximately
3,370 people live within 1 mile of the site, which is in a largely rural and light industrial area.
Llangollen Estates, a residential development, is several hundred feet beyond the southern
edge of the site. An estimated 130,000 people living within 3 miles of the site are served by
groundwater supplies. Another NPL site, the Delaware Sand and Gravel Landfill, is located
immediately across from Army Creek to the east of the site.
Site Responsibility: This site is being addressed through
Federal and potentially responsible
parties' actions.
NPL LISTING HISTORY
Proposed Date: 10/01/81
Final Date: 09/08/83
Threats and Contaminants
m
Volatile organic compounds (VOCs), such as benzene and dichloroethane, and
heavy metals, including chromium and mercury, are found in monitoring wells,
recovery wells, groundwater, and soils. The surface water of Army Creek contains
contamination from cadmium, chromium, mercury, iron, and zinc. People working
or trespassing on the site could be exposed to contaminants in the soil by direct
contact or ingestion of contaminated groundwater, or by inhalation of
contaminants in the air. Methane gas escaping from the landfill could cause
injuries if an explosion occurred.
March 1992
-------
Cleanup Approach
This site is being addressed in three stages: emergency actions and two long-term remedial
phases focusing on source control and cleanup of the contaminated groundwater.
Response Action Status
Emergency Actions: Tires on the site caught fire and threatened to ignite
nearby hazardous wastes. The fire was extinguished by New Castle County, and
the EPA provided emergency technical support and air monitoring during the fire
control efforts. New Castle County installed a groundwater recovery system designed to
capture contaminated groundwater. This series of downgradient pumping wells is designed to
prevent the contamination plume from reaching the source of the drinking water supply.
Pumping has separated contamination from the water supply and has eliminated migration of
the plume into the drinking water source.
Source Control: Control of the source of contamination of the site includes: (1)
installation of a multi-layer cap over the landfill; (2) continued operation of the
downgradient recovery well network; and (3) evaluation of the cap system and the
groundwater recovery network for five years by monitoring well water levels and by pumping
water and checking the water quality. Five years after the cap is in place, an evaluation will
be carried out to determine if installation of upgradient controls is necessary. At the same
time, the monitoring strategy for well water levels, pumping rates, and water quality will be
re-evaluated. Cleanup activities began in 1990, and are scheduled for completion in late
1995.
Groundwater: A detailed study of the nature and extent of contamination and
treatment alternatives for the water being pumped from the groundwater recovery
wells was completed in 1990, leading to the final selection of a groundwater
treatment remedy for recovery wells. The remedy, scheduled for completion in early 1994,
consists of the construction and operation of a water treatment facility, which will treat
recovered groundwater before discharge to surface water. The treatment plant is under
construction. A plan for long-term monitoring will be developed with respect to groundwater,
surface water, sediments, and associated wetlands once the facility begins operating.
Site Facts: On September 18, 1990, 18 potentially responsible parties signed a Consent
Decree to implement the cleanup actions at the site and to reimburse the EPA for past
response costs. Part of the settlement required the potentially responsible parties to deposit
$800,000 into a Trust Fund. The Department of the Interior, the National Oceanic and
Atmospheric Administration (NOAA), and the State of Delaware will ensure that this money
is used to create or enhance natural resources affected by contamination at the site.
March 1992 2 ARMY CREEK LANDFILL
-------
Environmental Progress
The County's installation of groundwater recovery wells to prevent the spread of
contamination into the drinking water supply and the EPA's emergency response to the
on-site fire have made the Army Creek site safer while clean up is underway.
Site Repository
Delaware Department of Natural Resources & Environmental Control, Superfund Branch,
715 Grantham Lane, New Castle, DE 19720
ARMY CREEK LANDFILL
March 1992
-------
CHEM-SOLV, IN
DELAWARE
EPAID#DED980714141
EPA REGION 3
Kent County
Cheswold
Site Description
The 1 1/2-acre Chem-Solv, Inc. site served as a small solvent distillation facility beginning in
1982. The facility recycled waste solvents by placing a drum on an electric coil heater, which
distilled the solvents into a second drum. The contents of the second drum were filtered into
a third drum, and the distilled residues were stored on site. In 1984, an explosion and fire at
the site destroyed the entire distillation facility. Witnesses observed fluids flowing off a
concrete pad into the soil. After the fire, the State conducted studies at the upper Columbia
Aquifer, which is adjacent to the site, where high concentrations of volatile organic
compounds (VOCs) were found in the upper zones of the aquifer, and low concentrations of
VOCs were found in the lower zones of the aquifer. An occupied 3-unit apartment building
is located on the site. About 5,500 residents live and are served by private wells within 3
miles of the site.
Site Responsibility: This site is being addressed through a
combination of Federal, State, and
potentially responsible parties' actions.
NPL LISTING HISTORY
Proposed Date: 06/10/88
Final Date: 08/30/90
Threats and Contaminants
The groundwater is contaminated with VOCs and heavy metals. The soil is
contaminated with VOCs from site waste disposal practices. The primary threat to
human health is drinking the contaminated groundwater. However, at this time,
the levels of contaminants reported in residential wells are within acceptable
drinking water standards. There is little potential for exposure to any
contamination from on-site soil because it was excavated and air-stripped in 1985.
Cleanup Approach
This site is being addressed in two stages: immediate actions and a long-term remedial phase
focusing on cleanup of the entire site.
March 1992
-------
Response Action Status
Immediate Actions: In 1985, the State excavated and treated contaminated soil
using a process that passed air through the soil to remove VOCs. Once
contamination levels of the soil were reduced to acceptable levels the soil was
returned to the site. Also, in 1985, the State started to recover and treat the VOCs in the
upper Columbia Aquifer, using an air stripping system. The air stripping process is still in use
by the State and continues to reduce contamination levels in the upper Columbia River.
Entire Site: A study of the nature and extent of contaminations and treatment
alternatives was completed in 1992. The cleanup remedy selected includes:
collection of contaminated groundwater using existing recovery wells until cleanup
levels are achieved; discharge of the groundwater to the Kent County wastewater treatment
plant or on-site treatment of the groundwater and discharge to local surface waters; and
monitoring of domestic, recovery, and monitoring wells until cleanup levels are achieved. A
State groundwater restriction zone and property deed restrictions regarding the installation of
wells in the restriction zone will continue until cleanup levels are achieved. The remedy also
ensures the provision of an alternate water supply to residences that may become
contaminated before cleanup is completed. On site monitoring wells will be disassembled and
removed from the site after cleanup is complete. The design of the cleanup remedy is
expected to begin in 1993.
Site Facts: In 1984 and 1985, the State of Delaware issued orders to one of the potentially
responsible parties to cease operations immediately, monitor groundwater, and remove all
contaminated soil; however, no actions were taken. In 1988, a Consent Order was signed by
the potentially responsible parties, the EPA, and the State, requiring the parties to conduct
an investigation into the contamination at the site.
Environmental Progress
The ongoing removal of VOCs from the soil and from the upper Columbia Aquifer by the
State is eliminating immediate threats and has reduced the potential for exposure to
hazardous materials. These actions have made the Chem-Solv, Inc. site safer while the final
cleanup remedy is being designed.
Site Repository
Delaware Department of Natural Resources & Environmental Control, Superfund Branch,
715 Grantham Lane, New Castle, DE 19720
CHEM-SOLV, INC. 5 March 1992
-------
COKER'S
SANITATION S
LANDFILLS
DELAWARE
EPA ID# DED980704860
Site Description
VICE
EPA REGION 3
Kent County
Cheswold
Other Names:
Reichold Chem Inc. #1
Coker's Landfill #1 & #2
The two Coker's Sanitation Service Landfills cover 25 acres near Cheswold. Coker's Landfill
#1 covers 10 acres, and Coker's Landfill #2 covers the 15 acres. The landfills were used for
disposal of latex rubber waste sludges from what is now the Reichold Chemicals, Inc. plant.
Coker's Landfill #1, operated from 1962 until 1976, consists of an unknown number of
unlined trenches. Coker's Landfill #2 was used under a State permit as a solid waste disposal
site from 1976 to 1980, and consists of 51 lined trenches each with a leachate collection and
monitoring system and a groundwater monitoring system. The landfills are located above two
groundwater systems: the Columbia Aquifer, which is a water table aquifer, and the Cheswold
Aquifer, which is a deeper artesian aquifer. Approximately 4,000 people live within a 3-mile
radius of the site, and two farms are adjacent to the landfills.
Site Responsibility:
This site is being addressed through
Federal, State, and potentially
responsible parties' actions.
NPL LISTING HISTORY
Proposed Date: 04/01/85
Final Date: 07/01/87
Threats and Contaminants
On-site sludge, leachate, and soil contamination consists of metals, volatile organic
compounds (VOCs) such as ethyl benzene and styrene from the latex rubber
wastes. Potential risks to health are direct contact with contaminated substances
on site or accidental ingestion of leachate. However, considering the remote,
rural, (partially restricted) nature of the site, the potential for public contact with
contaminants on or near the site appears to be slight. There is a potential for
contaminants to move off site to the nearby surface water and to the water table
aquifer and the regional aquifer, both of which supply city water. Area wetlands
also are potentially threatened, since drainage from Coker's Landfill #1 runs
through a wetlands area to the Willis Branch of the Leipsic River, and Coker's
Landfill #2 is partially bordered by wetlands.
March 1992
-------
Cleanup Approach
The site is being addressed in two stages: immediate actions and a long-term remedial phase
focusing on cleanup of the entire site.
Response Action Status
Immediate Actions: In 1989, buried drums and a bin were discovered by
geomagnetic surveys during the site investigation conducted by the parties
potentially responsible for the site contamination. These materials were
excavated, overpacked, and incinerated off site and drum staging areas were fenced for
protective purposes.
Entire Site: The potentially responsible parties conducted an investigation of the
drums and the entire site to help determine the extent of remaining
contamination and to identify alternative technologies for the cleanup. In 1990,
the EPA selected a cleanup remedy, which involves implementing deed restrictions, fencing
and posting warning signs to limit access to the site, covering exposed leachate seeps,
backfilling and seeding eroded areas in Landfill #2, grouting leachate collection wells in
Landfill #2, monitoring groundwater and inspecting the landfills on an ongoing basis, and
monitoring surface water at the Willis Branch. The design activities for the remedy began in
1991. Final cleanup activities are expected to begin in early 1993.
Site Facts: An Administrative Order on Consent was signed in 1988 by the EPA and
Reichold Chemicals, Inc., Nabisco Brands, Inc., and Rapid American Corp. for an
investigation to determine the extent of contamination and to identify alternative
technologies for the cleanup. On April 11, 1992, the potentially responsible parties signed a
Consent Decree with the EPA agreeing to implement cleanup actions.
Environmental Progress
Fencing the area of Coker's Landfills #\ and #2 removing contaminated drums have made
the site safer while the final cleanup remedy is being designed.
Site Repository
Clayton Post Office, Railroad Avenue, Clayton, DE 19938
COKER'S SANITATION SERVICE LANDFILLS 7 March 1992
-------
DELAWARE CITY
PVC PLANT
DELAWARE
EPA ID# DED980551667
EPA REGION 3
New Castle County
2 miles west of Delaware City
Other Names:
Stauffer Chemical Co.
Site Description
The 600-acre Delaware City PVC Plant site was built in 1966 and serves as a polyvinyl
chloride (PVC) production facility. During plant operations, earthen lagoons were used to
dump waste PVC. A wastewater treatment plant was built in 1970, however, sludges
continued to be dumped in the earthen lagoons on the site. Another area was used to bury
sludges from the treatment plant and then was capped. The Columbia Formation Aquifer,
which has been found to be contaminated, is used locally as a domestic water supply and is an
important source of drinking water in the area. There are approximately 400 people living
within a mile of the site. There also are four residences and two manufacturing operations on
the site. A water service company has wells within 3 miles of the site and serves an estimated
100,000 people.
Site Responsibility: This site is being addressed through
Federal and potentially responsible
parties' actions.
NPL LISTING HISTORY
Proposed Date: 10/01/81
Final Date: 09/01/83
Threats and Contaminants
The groundwater is contaminated with volatile organic compounds (VOCs) from
the waste disposal pits. The soil is contaminated with VOCs including vinyl
chloride. Drinking contaminated groundwater poses a health threat to nearby
residences, and on-site workers also may be exposed to contaminants by coming in
contact with the soils.
Cleanup Approach
This site is being addressed in four stages: immediate actions and three long-term remedial
phases focusing on cleanup of the lagoon areas, groundwater treatment and cleanup of the
PVC storage area and sludge pits, and cleanup of the remaining areas.
March 1992
-------
Response Action Status
Immediate Actions: Alternate water supplies were provided to users of on-site
residential wells and off-site water supply wells to eliminate the threat from
contaminated groundwater.
Lagoon Areas: The remedies selected for cleanup of the lagoon area include:
excavating sludge and contaminated soils, selling sludge product to the maximum
extent practicable, and disposing of residuals off-site; installing a double synthetic
liner in a pond, aeration basins, and installing a tank in the off-grade batch pits; and
monitoring groundwater contamination by using test wells. Cleanup of the lagoon was
completed in mid-1992.
Groundwater, PVC Storage Area and Sludge Pits: This cleanup phase
contains two components: groundwater treatment and cleanup of the PVC storage
area and sludge pits. The remedies selected for groundwater contamination
include: installing groundwater recovery wells at the northern and southern edges of the
contaminated plume; treating the water through air stripping and discharging it into the
Delaware River; and installing additional monitoring wells to evaluate the recovery system.
The remedies selected for cleaning up the PVC storage area and sludge pits include: covering
and capping the areas; covering the existing synthetic membrane with a drainage layer and a
second membrane; and establishing a vegetative cover on topsoil. The potentially responsible
parties currently are well into construction. They have completed several ponds, begun
pumping and treating the groundwater, and completed capping in two areas. In 1992, the
cleanup remedy was modified to include the construction of a stormwater pond to contain
contaminated runoff prior to treatment. All cleanup was completed in mid-1992; however, the
groundwater recovery system continues to operate to ensure that contamination will reach
acceptable levels.
Remaining Areas: In early 1993, the potentially responsible parties are expected
to begin investigating to identify the nature and extent of contamination and to
determine cleanup alternatives for the remaining areas of the site.
Site Facts: In 1984, the EPA and the State entered into a Consent Order with the
potentially responsible parties to perform studies of cleanup alternatives and all necessary
cleanup actions to eliminate contamination at the site. In 1987, a second agreement was
reached by the EPA and the parties that outlined the details of the cleanup design and
implementation.
DELAWARE CITY PVC PLANT 9 March 1992
-------
Environmental Progress
The provision of an alternate water supply to residents and area businesses and the start of
cleanup activities at the areas of concern at the Delaware City PVC Plant site have
eliminated the potential for exposure to contaminated groundwater and soils. Contamination
levels at the Delaware City PVC Plant site have been reduced as cleanup activities continue.
Further studies to identify other potential sources of contamination are expected to begin in
early 1993.
Site Repository
Delaware Department of Natural Resources and Environmental Control, Superfund Branch,
715 Grantham Lane, New Castle, DE 19720
March 1992
10
DELAWARE CITY PVC PLANT
-------
DELAWARE
SAND & GRAY
LANDFILL
DELAWARE
EPA ID# DED000605972
Site Description
EPA REGION 3
New Castle County
2 miles southwest of the
City of New Castle
Other Names:
Delaware Sand & Gravel Co. Landfill
Delaware Sand & Gravel-Llangollen
Army Creek Landfills
The 27-acre Delaware Sand & Gravel Landfill site is an inactive industrial waste landfill
located adjacent to another NPL site, the Army Creek Landfill. The site has four disposal
areas, referred to as the Drum Disposal, Inert Disposal, Ridge, and Grantham South areas.
Between 1968 and 1976, the site accepted household and construction wastes and at least
7,000 drums containing liquids and sludges from perfume, plastics, paint, and petroleum
refining processes. The Drum Disposal area is believed to be the major source of organic
contamination of the groundwater. In 1984, approximately 600 drums were removed from the
surface of the Drum Disposal area, and it was then covered with soil and a vegetative cover.
The Ridge area consists of contaminated surface soil. The Inert Disposal area contains
various wastes buried 25-40 feet thick. Cars, trucks, and storage tanks are scattered on the
surface. The Grantham South area is believed to contain construction debris and chemical
wastes. Approximately 2,000 people live within a mile of the site. The site is located in a
mixed residential and lightly industrialized area. Properties adjoining the site include two
residences and a maintenance garage. The nearest residence is about 30 feet from the edge
of the landfill. The Llangollen Estates housing development is about 1/4 mile southwest of
the site. Underlying the landfill is the Potomac Aquifer, which is accessed about 1 1/4 miles
south of the site and is used as a public water source.
Site Responsibility: This site is being addressed through
Federal and State actions.
NPL LISTING HISTORY
Proposed Date: 10/01/81
Final Date: 09/01/83
Threats and Contaminants
The groundwater is contaminated with volatile organic compounds (VOCs) and
semi-volatile organic compounds from former disposal practices. Heavy metals
including arsenic, cadmium, chromium, lead, and mercury also have been detected
in off-site groundwater. The soil is contaminated with VOCs, polychlorinated
biphenyls (PCBs), and heavy metals. Specific contaminants detected in Army Creek
include cadmium, chromium, mercury, iron, and zinc. The greatest threat to health
is accidental ingestion of groundwater. Workers, trespassers, and nearby residents
may be exposed to contaminants in the soil and air.
11
March 1992
-------
Cleanup Approach
This site is being addressed in three stages: immediate actions and two long-term remedial
phases focusing on cleanup of the entire site and Grantham South Area.
Response Action Status
Immediate Actions: To reduce the threat of groundwater contamination, New
Castle County installed a recovery system downgradient of the site to prevent
contaminated water from reaching the nearby public water supply well field. The
groundwater is decontaminated prior to being discharged to Army Creek and Army Pond.
Continued monitoring in the area indicates that the groundwater recovery system has been
effective in controlling the migration of contaminated groundwater. In 1984, the EPA
removed approximately 600 drums from the Drum Disposal area. The flammable solids and
PCB materials were bulked, drummed, and safely disposed of. A drum shredder was used to
process non-flammable solids for disposal. Shredded material was placed in box trailers and
shipped to disposal facilities. Air monitoring was conducted in the work area and at the site
perimeter to determine the affect of site activities on ambient air. Work areas of the site
were regraded, hydroseeded, and spread with mulch. In 1991, a security fence was installed
around the drum disposal area. The installation of a slurry wall around the drum disposal
area is being planned to keep contaminants contained prior to final cleanup.
Entire Site: The selected actions for remaining cleanup activities include:
excavation and on-site incineration of approximately 36,000 tons of contaminated
soil and wastes from the Drum Disposal and Ridge areas with on- or off-site
disposal of residual ash; reshaping of the excavated area and establishment of a vegetative
cover; removal and off-site disposal of all surface debris from the Inert area; soil capping of
buried, waste materials; and a groundwater pump and treatment system with discharge to
Army Creek and continued groundwater monitoring. The design of the remedy for the Drum
Disposal area and Ridge area is expected to be completed in 1994, with the remedy being
implemented shortly after. The remedy for the Inert area will follow. The construction of the
groundwater treatment system is scheduled to begin in mid-1992.
Grantham South Area: In 1991, the EPA completed the construction of a cap
over the Grantham South Area to contain the source of contamination..
Site Facts: In 1976, the State issued an enforcement action requiring the potentially
responsible parties to discontinue disposal activities. EPA is currently negotiating a removal
order to require the potentially responsible parties to design and install a slurry wall around
the Drum Disposal Area.
March 1992 12 DELAWARE SAND & GRAVEL LANDFILL
-------
Environmental Progress
Numerous cleanup activities have been completed at the Delaware Sand & Gravel Landfill
site, including fencing; removing contaminated materials; capping; air monitoring; and
regrading, hydroseeding, and spreading mulch over the Drum Disposal area. The groundwater
recovery system is controlling the spread of contamination from the site while final cleanup
actions are being completed.
Site Repository
Delaware Dept. of Natural Resources & Environmental Control, Superfund Branch,
715 Grantham Lane, New Castle, DE 19720
DELAWARE SAND & GRAVEL LANDFILL
13
March 1992
-------
DOVER AIR FORCE EPAKR,ECG?N 3
^ Kent County
BASE ••* Dover
DELAWARE
EPAID#DE8570024010
Site Description
The 3,700-acre Dover Air Force Base (AFB) site is the base of operation for the 436th
Military Airlift Wing. The base contains 23 areas on site that were used for disposing of
industrial waste. An estimated 23,000 cubic feet of waste were disposed of from 1951 to
1970. The base's operations generated numerous wastes, some in drums, including paints,
solvents, waste fuels, and oil. These wastes were disposed of in various on-base locations
including 12 landfills and three fire training areas. All disposal sites are earth-covered to a
depth of 3 feet, with the exception of the construction debris landfill. Access to the site is
restricted. There are approximately 1,000 people living on base, and 39,000 people living
within a 3-mile radius of the site. The distance from the base to the nearest residence is
about one half mile, and the site is located in a commercial and residential area that is
densely populated. The base well system serves about 10,000 people and is routinely
monitored by the Air Force. Contaminants have not been found in this system.
Site Responsibility: This site is being addressed through
Federal and State actions. Final Date: Q3/13/89
Threats and Contaminants
Shallow on-site groundwater is contaminated with heavy metals including arsenic
and cadmium and volatile organic compounds (VOCs) from former waste disposal
practices. A variety of VOCs have been detected in off-site groundwater including
trichloroethylene (TCE), tetrachlorethylene (PCE) and carbon tetrachloride.
VOCs also have been detected in the sediments. VOCs and heavy metals
including mercury, chromium, and cadmium have been detected in on-site stream
waters. Potential health threats include exposure to contaminated groundwater
used for potable purposes and ingestion of contaminated fish and wildlife. Direct
contact with contaminated surface water or sediments during recreational or site
activities by area residents and workers also is a concern. A nearby freshwater
wetlands is threatened by site contamination.
14 March 1992
-------
Cleanup Approach
This site is being addressed in four stages: initial actions and three long-term remedial phases
focusing on cleanup of Fire Training Area #3, the Industrial Area, and on-site groundwater.
Response Action Status
Initial Actions: The Air Force has cleaned up the industrial waste basins and a
drum site, and has provided an alternate water supply to affected residents. A
landfill and some hazardous waste areas were excavated during the runway
extension in 1988 and 1989.
Fire Training Area #3: Cleanup activities began early in 1992. To date, an
underground storage tank, and oil/water separator, and all associated piping were
removed from the site. Contaminated soils surrounding the tanks and underlying
the fire training pit also were removed. The area is scheduled to be capped by late 1993 at
which time all cleanup activities for this phase of the cleanup are scheduled to be completed.
Industrial Area: In 1990, the Air Force began an investigation into the nature
and extent of contamination and to identify cleanup alternatives. The area is
comprised of source areas including treatment units, buildings, hangars, and
industrial sewer lines that are close together. The Air Force has proposed cleanup plans for
source control and the removal of contamination floating on the water table, as well as the
removal of contaminated soils. A final decision on the remedy is expected in 1993.
On-Site Groundwater: Groundwater monitoring currently is underway as part of
the ongoing site studies. In 1990, the Air Force began an investigation into the
extent and nature of groundwater contamination. A decision on the remedy in
expected to be made in mid-1994.
Site Facts: The EPA, the Air Force, and the State of Delaware have entered into an
Interagency Agreement (LAG) for comprehensive cleanup and compliance with Federal
standards. The Dover Air Force Base also is participating in the Installation Restoration
Program, a specially funded program established by the Department of Defense (DOD) in
1978 to identify, investigate, and control the migration of hazardous contaminants at military
and other DOD facilities.
Environmental Progress
By cleaning up the industrial waste basins and drum sites and providing an alternate water
supply to residents and workers at the Base, the Air Force has reduced the risk of immediate
threats from the Dover Air Force Base site while further cleanup activities are being
conducted.
DOVER AIR FORCE BASE 15 March 1992
-------
Site Repository
Dover Air Force Base, 436 Military Airlift Wing, Dover, DE 19902
March 1992 16 DOVER AIR FORCE BASE
-------
DOVER GAS
LIGHT CO.
DELAWARE
EPA ID# DED980693550
Site Description
EPA REGION 3
Kent County
Dover
The 1-acre Dover Gas Light Co. site operated as a coal gasification plant from 1859 to 1948
and produced gas for street lamps from coal. When the plant was closed in 1948, the
structures, except for a brick garage, were demolished. Much of the plant was removed, but
sections of the tanks and other process equipment containing coal oil, coal tar, coke, and
possibly acid were buried on site. In 1984, remains of this coal gasification plant were found
buried on the site. The site currently is used as a parking lot, with a museum immediately
adjacent. Approximately 10,000 people are within 1 mile of the site and an estimated 454,000
people are served by public and private wells within 3 miles of the site. Seven of Dover's 14
municipal supply wells are located within 1 mile of the site. The closest supply well, 1,000
feet from the site, draws from the Cheswold aquifer and is part of Dover's municipal water
system; however, the Dover municipal system draws water from a lower uncontaminated
aquifer. The municipal wells were sampled in 1988 and did not show signs of contamination.
Also nearby are a cemetery and an historic church.
Site Responsibility:
This site is being addressed through
Federal, State, and potentially
responsible parties' actions.
NPL LISTING HISTORY
Proposed Date: 01/22/87
Final Date: 10/04/89
Threats and Contaminants
Specific contaminants detected in the groundwater and soil include volatile organic
compounds (VOCs), lead, and polycyclic aromatic hydrocarbons (PAHs) from
former site activities. Possible health threats include ingestion of or direct contact
with the contaminated groundwater or soil. Although municipal supply wells are
nearby, sampling has indicated that contamination in the upper aquifer does not
pose a threat to Dover's water supply.
17
March 1992
-------
Cleanup Approach
This site is being addressed in a single long-term remedial phase focusing on contamination at
the entire site.
Response Action Status
Entire Site: A potentially responsible party is conducting an investigation to
determine the nature and extent of contamination and to identify cleanup
alternatives for soil, groundwater, and potential river sediment contamination at
the site. The investigation is planned to be completed in 1993, after which the party will
begin cleanup. Current investigation efforts include determining whether wetlands or the
river have been contaminated, conducting groundwater studies, implementing on-site borings,
and conducting an archaeological study.
Environmental Progress
After listing the Dover Gas Light Co. site on the NPL, the EPA determined that site
conditions do not threaten nearby residents or the environment while the potentially
responsible parties are conducting investigations and cleanup activities at the site.
Site Repository
Not established.
March 1992 18 DOVER GAS LIGHT CO.
-------
E.I. DU PONT DE
NEMOURS & CO., IN
(NEWPORT PIGMENT
PLANT LANDFILL)
DELAWARE
EPA ID# DED980555122
Site Description
EPA REGION 3
New Castle County
Along the Christiana River in Newport
Other Names:
port Pigments
ewport Pigments Plant
The E.I. Du Pont de Nemours & Co., Inc. (Newport Pigment Plant Landfill) site is a pigment
manufacturing facility consisting of two industrial landfills: the 7-acre North Disposal Area
and the 15-acre South Disposal Area. From 1902 to 1929, the plant manufactured lithopone,
a white inorganic pigment. In 1929, Du Pont purchased the plant and continued to produce
lithopone along with other organic and inorganic pigments. As part of the plant operations,
the waste was disposed of in the landfills. Ciba-Geigy purchased the pigment plant in 1984,
while Du Pont retained a magnetic tape manufacturing facility. Approximately 21,000 people
reside within a 3-mile radius of the site. Also within 3 miles of the site are three public water
supply wells that serve approximately 150,000 people. There are a number of private supply
wells within 1/2 mile of the site. Fifteen residential wells are threatened by groundwater
contamination. The site is within a 100-year flood plain. Contaminated wetlands are located
immediately adjacent to both landfills. The Christiana River flows between the landfills and
is used for recreational purposes.
Site Responsibility:
This site is being addressed through
Federal and potentially responsible
parties' actions.
NPL LISTING HISTORY
Proposed Date: 01/22/87
Final Date: 02/16/90
Threats and Contaminants
ZGJ
Heavy metals and chlorinated solvents from past disposal practices have been
detected in the groundwater. Monitoring well information indicated contamination
of the underlying Columbia and Potomac aquifers. Heavy metals have been
detected at the landfills, underneath the Ciba-Geigy plant, and in wetland
sediments and surface water. The contaminated groundwater may migrate and
eventually pose a health risk to owners of nearby private wells. The groundwater
contamination also poses a threat to the Christiana River and the wetlands.
Surface soil contamination poses a threat to wildlife and to workers who come in
direct contact with contaminants on the unpaved portions of the plant or people
using the adjacent ballpark.
19
March 1992
-------
Cleanup Approach
This site is being addressed in a single long-term remedial phase focusing on cleanup of the
entire site.
Response Action Status
Entire Site: The parties potentially responsible for the site contamination started
an investigation in 1988 to determine the extent of the contamination and to
identify alternative cleanup technologies. The investigation is scheduled to be
completed in 1992. After completion of the studies, the parties, under EPA supervision, will
begin cleanup of contaminants at the site.
Site Facts: Du Pont entered into an Administrative Order on Consent with the EPA in
1988, under which Du Pont agreed to perform a study to determine the nature and extent of
the contamination and to identify alternative cleanup technologies.
Environmental Progress
After adding this site to the NPL, the EPA performed a preliminary evaluation at the E.I. Du
Pont de Nemours & Co., Inc. (Newport Pigment Plant Landfill) site and determined that it
currently did not pose an immediate threat to public health and the environment while
further investigations continue and cleanup alternatives are being identified.
Site Repository
Kirkwood Highway Library, 600 Kirkwood Highway, Wilmington, DE 19808
March 1992 20 E.I. DU PONT DE NEMOURS & CO., INC.
(NEWPORT PIGMENT PLANT LANDFILL)
-------
HALBY
CHEMICAL CO.
DELAWARE
EPA ID# DED980830954
EPA REGION 3
New Castle County
Wilmington
Site Description
The 14-acre Halby Chemical Co. site operated as a chemical manufacturing facility from 1948
to 1977. Wastewater from the production of chemicals at the plant was discharged into a
1 1/2-acre unlined lagoon and then discharged into a tidal marsh leading to the Lobdell
Canal. Currently, the lagoon receives intertidal flow through an interstate highway drainage
ditch. During preliminary investigations, drums from a storage area also were found to be
leaking. Preliminary sampling results indicated significant contamination of lagoon sediment
and soil in the vicinity of the former process buildings. There also is significant soil
contamination underlying the backfilled portions of the waste lagoon. Approximately 1,800
people live within a mile of the site. Area residents receive water from the Artesian Water
Company, which draws water from several uncontaminated wells. There is only one known
residential well and one public well within 3 miles of the site.
Site Responsibility: This site is being addressed through
Federal, State, and potentially
responsible parties' actions.
NPL LISTING HISTORY
Proposed Date: 09/18/85
Final Date: 06/01/86
Threats and Contaminants
m
The groundwater is contaminated with volatile organic compounds (VOCs) and
heavy metals including arsenic and zinc. Sampling of the lagoon sediments
revealed high levels of carbon disulfide, zinc, arsenic, and lead. The surface water
is contaminated with heavy metals including arsenic, lead, cadmium, and mercury.
Heavy metals including arsenic and zinc, and polycyclic aromatic hydrocarbons
(PAHs) were detected in the soil. Potential health threats include accidental
ingestion or inhalation of, or direct contact with contamination in the groundwater,
surface water, lagoons, or soil.
21
March 1992
-------
Cleanup Approach
This site is being addressed in two long-term remedial phases focusing on cleanup of the soil
and cleanup of the air, groundwater, and sediments contamination.
Response Action Status
Soil: Based on the EPA's investigations, a remedy for the soil inside the process
plant area was selected in 1991. The remedy includes: consolidation of all debris;
soil sampling; a study to determine the treatability of soil through soil stabilization
techniques; excavation, stabilization, and backfilling of the top 6 inches of contaminated
surface soil; placement of an asphalt cap over the stabilized soil; implementation of deed
restrictions; and public education programs. Long-term monitoring and site maintenance,
which will ensure the effectiveness of the technical design of the remedy, began in 1992.
Air, Groundwater, and Sediments: In 1991, the EPA is scheduled to begin an
investigation of the nature and extent of contamination in the air, groundwater,
and sediments in the outfall area and tidal marsh area. This study is scheduled for
conclusion in 1993, at which time a remedy will be selected.
Site Facts: The EPA and the party potentially responsible for site contamination signed a
Consent Decree in early 1992 under which the party has agreed to perform cleanup actions
at the Halby Chemical Co. site.
Environmental Progress
After adding the Halby Chemical Co. site to the NPL, the EPA performed preliminary
investigations and determined that conditions at the site do not pose an immediate threat to
public health or the environment while technical designs addressing soil cleanup and further
investigations are underway.
Site Repository
Wilmington Institute Library, 10th and Market Streets, Wilmington, DE 19801
March 1992 22 HALBY CHEMICAL CO.
-------
HARVEY &
ft Q HIV/I IMC '"-/ About 5 miles from Kirkwood
DELAWARE
EPA ID#DED980713093
Site Description
The Harvey & Knott Drum, Inc. site operated as an open dump and burning area between
1963 and 1969 on a portion of a 20-acre site. The facility accepted sanitary, municipal, and
industrial wastes believed to be sludges, paint pigments, and solvents. Wastes were emptied
onto the ground surface into excavated trenches or left in drums, some of which were buried
on site. Several hundred drums have been removed from the site. A security fence,
enclosing about 2 1/2 acres, was erected around the most visible areas of contamination. The
enclosed area included drum stockpiles, waste piles, and a small pond. Trailer homes and a
residential development are located to the north of the property. Water supplies for some of
the nearby residences are obtained from a shallow water-table aquifer. There are
approximately 300 people living within 1 mile of the site. The site facility is set back several
hundred feet from the highway in an open field in a relatively undeveloped area and is
surrounded by woodlands. Wetlands are located to the south of the site.
n*»~ ~-u-r* TU- v • u • AA A^ u NPL LISTING HISTORY
Responsibility: This site is being addressed through
Federal, State, and potentially
responsible parties' actions.
Proposed Date: 07/01/82
Final Date: 09/01/83
Threats and Contaminants
m
"<£
Specific contaminants detected in the groundwater include volatile organic
compounds (VOCs) such as ethyl benzene and toluene and heavy metals including
arsenic, cadmium, and lead. Heavy metals were detected in on-site sediments and
surface water. Contaminants detected in soils and sediments include VOCs, heavy
metals, and polychlorinated biphenyls (PCBs). Potential health threats exist
through accidental ingestion of, inhalation of, and direct contact with contaminated
groundwater. Trespassers and workers may be exposed to contaminants in on-site
soil and waste through accidental ingestion, direct contact, and inhalation at levels
that pose health concerns. Contaminated surface soils beyond the western
property boundary pose similar concerns for persons entering that area. Wetlands
also may be threatened.
23 March 1992
-------
Cleanup Approach
The site is being addressed in two stages: immediate actions and a long-term remedial phase
focusing on drum removal and groundwater pumping and treatment.
Response Action Status
Immediate Actions: The State supplied emergency drinking water to affected
residents in 1981. In 1982, the EPA completed immediate measures which
included installing a security fence, overpacking and staging 43 leaking drums, and
conducting a sampling survey. In addition, 17 monitoring wells were installed to identify the
nature and extent of groundwater contamination. In 1983 and 1984, 46 drums were removed
and disposed of off site, a soil berm and a surface drainage ditch around a PCB-contaminated
waste pile were constructed, 500 empty drums were crushed and staged, and 200 partially
filled drums were staged.
Drum Removal and Groundwater Pumping and Treatment: Cleanup
technologies selected to address the first phase, contaminated drums, include:
(1) the removal of surface and subsurface drums; (2) extraction and on-site
treatment of surface water; (3) excavation of sediments, soil, and bulk wastes with off-site
disposal at an approved facility; (4) disposal of sludges, drums, and other debris at an off-site
facility; (5) extraction and treatment of groundwater using effluent to flush contaminants
from on-site surface and subsurface soils; and (6) preparation of the site for a flushing pipe
network entailing grading, covering with clean soil, and revegetating. Cleanup activities are
presently underway. The removal of surface and subsurface drums and the disposal of
sludges have been accomplished. Currently under review, to determine if cleanup is
necessary, is the extraction and treatment of surface water, groundwater, and flushing pipe
network. The phase one excavation and removal of soil, sediments, and bulk wastes was
completed in early 1990. The EPA currently is conducting an investigation of the second
phase, groundwater pumping and treatment. The second phase investigation will define the
contaminants of concern and will identify whether there is a need for groundwater cleanup.
The investigation is planned to be completed in 1992.
Site Facts: In 1977, a Consent Decree was entered into between the EPA and a party
potentially responsible for the contamination, requiring the party to conduct an investigation
into the nature and extent of contamination at the site. In 1988, a Consent Decree was
entered into between the EPA and another potentially responsible party. In 1988, the EPA
filed suit against a potentially responsible party to recover the costs incurred by the Federal
government.
Environmental Progress
By providing an emergency drinking water supply to affected residents, installing a security
fence around the site, and removing all the surface and subsurface leaking drums, soils, and
sediments the EPA has significantly reduced the potential for exposure to hazardous
materials at the Harvey & Knott Drum, Inc. site. Cleanup of contaminated groundwater
currently is being addressed.
March 1992 24 HARVEY & KNOTT DRUM, INC.
-------
Site Repository
Delaware Department of Natural Resources & Environmental Control, Superfund Branch,
715 Grantham Lane, New Castle, DE 19720
HARVEY & KNOTT DRUM, INC.
25
March 1992
-------
KENT COUNTY
LANDFILL
(HOUSTON)
DELAWARE
EPA ID# DED980705727
Site Description
EPA REGION 3
Kent County
About 2 miles north of Houston
The 100-acre Kent County Landfill (Houston) site was operated by the County from 1969 to
1980. Among the wastes accepted were residential trash, pesticides, sludges from poultry
processing plants, oil sludges, hospital wastes, waste polymers, and solvents. The landfill holds
an estimated 2 million cubic yards of waste and fill materials. The wastes were deposited in
unlined trenches. In 1980, the County covered the landfill with 3 to 5 feet of sandy soil and
planted grass and other vegetation. In 1980 and 1984, the EPA found contaminants in a
monitoring well in the water table aquifer underlying the site. The EPA also found
contaminated leachate seeping from the landfill. Approximately 684 people use private wells
within 3 miles of the site. About 1,200 acres of cropland within 3 miles of the site are
irrigated by well water, and surface water near the site is used for recreational purposes.
Site Responsibility:
This site is being addressed through a
combination of Federal, County, and
potentially responsible parties' actions.
NPL LISTING HISTORY
Proposed Date: 06/16/88
Final Date: 08/30/90
Threats and Contaminants
The groundwater is contaminated with volatile organic compounds (VOCs)
including benzene and vinyl chloride and heavy metals such as chromium, arsenic,
and manganese from former disposal practices at the site. The soil in leachate
seep sediments is contaminated with heavy metals including iron, manganese,
barium, and cobalt. People who trespass on the unfenced site and come in direct
contact with or accidentally ingest contaminated groundwater or leachate may be
at risk.
Cleanup Approach
The site is being addressed in a single long-term remedial phase focusing on cleanup of the
entire site.
26
March 1992
-------
Response Action Status
Entire Site: The parties potentially responsible for the site contamination are
conducting a study to determine the nature and extent of contamination. This
study, which began in 1991, will recommend alternatives for the final cleanup.
After completion of the study, the potentially responsible parties, under EPA supervision, will
perform cleanup activities to reduce groundwater and soil contamination to acceptable levels.
Environmental Progress
After adding this site to the NPL, the EPA performed a preliminary investigation and
determined that contamination at the Kent County Landfill (Houston) site currently does not
pose an immediate threat to the public or the environment while site investigations to select
the cleanup remedy are underway.
Site Repository
Milford Public Library, 214 South Walnut Street, Milford, DE 19963
KENT COUNTY LANDFILL (HOUSTON)
27
March 1992
-------
KOPPERS CO., INC,
(NEWPORT PLANT)
DELAWARE
EPA ID# DED980552244
Site Description
EPA REGION 3
New Castle County
Newport
The 317-acre Koppers Co., Inc. (Newport Plant) site operated as a wood preserving plant
from 1929 until 1971. During operations, Koppers loaded railroad ties and telephone poles
into cylinders and pressure-injected them with either creosote or a mixture of No. 2 fuel oil
and pentachlorophenol (PCP). The site contains a pond filled with water used for fire
protection, and two effluent holding ponds and sumps which discharge into wetlands. In
1971, Koppers sold the site to Du Pont. As part of the sales agreement, Koppers removed
the process tanks equipment. All structures were removed from the site; the site currently is
vacant. Two or more potential historical homesteads exist on the property. In 1984, the
EPA detected creosote compounds in on-site soil and in nearby creek sediments. The
Artesian Water Company draws drinking water from three wells within 3 miles of the site and
blends the water with other water to serve its 150,000 customers. The three wells tap the
Lower Potomac Formation, hydraulically connected to the overlying Columbia Formation,
permitting water to move between them. Wetlands are found both on and around the site.
Site Responsibility: This site is being addressed through
Federal and potentially responsible
parties' actions.
NPL LISTING HISTORY
Proposed Date: W/26/89
Final Date: 08/30/90
Threats and Contaminants
ZEJ
Soil and nearby creek and pond sediments are contaminated with polycyclic
aromatic hydrocarbons (PAHs) from the wood preserving treatment processes.
Potential health threats include accidental ingestion of and direct contact with
contaminated soil and sediments. Wetlands may also may be threatened.
28
March 1992
-------
Cleanup Approach
This site is being addressed in a single long-term remedial phase focusing on cleanup of the
entire site.
Response Action Status
Entire Site: In 1991, an investigation began to determine the nature and extent
of contamination at the site. Currently, a work plan and schedule are being
negotiated with Du Pont and Beaze to complete the investigation. Once the
investigation is completed, final cleanup technologies will be selected.
Environmental Progress
The EPA assessed conditions at the Koppers Co., Inc. (Newport Plant) site and determined
that no intermediate actions were required to make the site safer while investigations are
underway.
Site Repository
Not established.
KOPPERS CO., INC. (NEWPORT PLANT)
29
March 1992
-------
NCR CORP.
(MILLSBORO PLA
DELAWARE
EPA ID# DED043958388
Site Description
EPA REGION 3
Sussex County
1/2 mile southeast of Millsboro
Other Names:
First Freedom Center
NCR Corp. manufactured cash registers from 1967 to 1975 and electronic equipment from
1975 to 1980, at this approximately 130-acre site 1/2 mile southeast of Millsboro. Between
1967 and 1974, the company ran electroplating processes that produced a chromium-bearing
waste. Workers treated this waste on site. Some plating sludges were buried in a pit lined on
the bottom with bentonite. NCR subsequently excavated this material. Two of three
concrete-lined storage lagoons on site contained toxic materials that were later drained and
removed. In 1981, the First National Bank of Maryland bought the property. NCR assumed
all environmental responsibilities in the deed of sale. The State required NCR to monitor
groundwater after the site was closed. Monitoring results showed that groundwater under the
property was contaminated with volatile organic compounds (VOCs) and metals. The
contaminated groundwater is entering Iron Branch Creek, which flows into a recreational
stream called Indian River. Riverview is located close to the site and is a community of
about 30 small houses that draw drinking water supplies from groundwater wells. Quarterly
monitoring of groundwater is ongoing. Contamination levels of the residential wells remain
within acceptable levels. About 4,700 people depend on public and private wells within 3
miles of the site as a source of drinking water. The nearest well is 10 feet away from the
site, and the nearest people are 150 feet away. An estimated 1,000 people live within 1 mile;
approximately 4,200 are within 3 miles of the site.
Site Responsibility: This site is being addressed through a
combination of Federal, State, and
potentially responsible parties' actions.
NPL LISTING HISTORY
Proposed Date: 04/01/85
Final Date: 07/01/87
Threats and Contaminants
The groundwater is contaminated with VOCs including trichloroethylene (TCE)
and with total and hexavalent chromium. A plume of solvent waste has reached
Iron Branch Creek, but no domestic supply wells are affected. People who come
into direct contact with or accidentally ingest contaminated groundwater or surface
water may be at risk.
30
March 1992
-------
Cleanup Approach
The site is being addressed in two stages: initial actions and a long-term remedial phase
directed at cleanup of the entire site.
Response Action Status
Initial Actions: NCR excavated chromium-bearing sludge from a bentonite lined
pit and drained and removed toxic materials from two concrete-lined storage
lagoons. NCR continued to monitor groundwater after site closure, and installed
28 wells for that purpose. In 1988, an air stripper and a recovery well were put into
operation in an effort to prevent off-site migration of contaminants.
Entire Site: Under State supervision, NCR conducted an intensive study of
groundwater contamination at the site. This investigation explored the nature and
extent of pollution and recommended the following cleanup remedy for the site:
extracting contaminated groundwater using recovery wells; treating VOC contamination in
groundwater by air stripping and carbon adsorption techniques; treating chromium
contamination by coagulation and filtration, as necessary; discharging treated groundwater to
surface water or on-site groundwater infiltration galleries; conducting a well survey to
determine the location of all wells within a 1-mile radius of the site; monitoring groundwater
on a quarterly basis; instituting an annual monitoring program for surface water and sediment
of Iron Branch; and instituting restrictions for groundwater use within the contaminated
groundwater plume and enacting deed restrictions regarding the installation of wells within
the plume. The design of the cleanup activities is expected to begin in mid-1992.
Site Facts: A Consent Order for NCR to undertake initial response measures and a study
to determine the nature and extent of contamination and to identify alternatives for cleanup
was signed in 1988. The State ordered NCR to undertake an EPA-approved site closure in
1981.
Environmental Progress
The removal of contaminated sludge and the installation of monitoring wells to chart
contaminant levels, as well as the construction of an air stripper and recovery well, have
reduced the potential for exposure to hazardous materials at the NCR Corp. (Millsboro
Plant) site while cleanup activities are being designed.
Site Repository
Millsboro Town Hall, 322 Wilson Highway, Millsboro, DE 19966
NCR CORP. (MILLSBORO PLANT) 31 March 1992
-------
NEW CASTLE SPILL
DELAWARE
EPA ID# DED058980442
Site Description
EPA REGION 3
New Castle County
New Castle
Other Names:
Witco Chem. Co.
TRIS Spill Site
Since 1954, the Witco Chemical Company processed materials used in the production of
plastic foam on this 6-acre site in New Castle. Operators stored drums containing
pre-polymer feedstocks and spent solvents on the southern boundary of their property
adjacent to the New Castle Board of Water and Light (NCBW&L) property. In 1977,
employees of NCBW&L noticed dead grass near the drum storage area. Shortly after
sampling, during which contaminants at levels above the accepted State and EPA levels were
found, the NCBW&L was directed by the Delaware Department of Natural Resources and
Environmental Control (DNREC) to pump the shallow aquifer and to discharge the water to
the nearby wetlands. Subsequent testing showed that the wetland had not been contaminated.
The surrounding area is industrial and residential; 5,500 people live within 3 miles of the site.
The closest home is 750 feet from the site. The shallow aquifer being used by the NCBW&L
was taken out of service, and measures are being taken to prevent its future use.
Approximately 7,000 people now are served by another source for their potable water supply.
Site Responsibility: This site is being addressed through a
combination of Federal, State, and
potentially responsible parties' actions.
NPL LISTING HISTORY
Proposed Date: 12/12/82
Final Date: 09/08/83
Threats and Contaminants
Trichloroethylene (TCE) is found in the groundwater, but is believed to be from
an off-site source now under investigation by the State. The groundwater also is
contaminated with other volatile organic compounds (VOCs) including acetone
and tris-chloropropyl phosphate (TRIS), a semi-volatile organic compound. TRIS,
a flame retardant, which can be related back to Witco's activities, was detected in
soils near the drum storage area. On-site soil is contaminated with VOCs,
polychlorinated biphenyls (PCBs), TCE, creosote, and phthalates from plastics
production. However, soil contamination was not determined to pose a significant
threat to human health and to the environment. Drinking contaminated
groundwater from the aquifer could pose a health threat to people; however, a
new water supply has been provided to residents found to be at risk. Wetlands are
adjacent to the site and are threatened by runoff of surface contamination. The
site is secured by a locked fence.
32
March 1992
-------
Cleanup Approach
The site is being addressed in a long-term remedial phase focusing on cleanup of the entire
site.
Response Action Status
Entire Site: The shallow aquifer used by the NCBW&L was taken out of service
and affected residents were provided an alternative water source. From 1977 to
1978, the NCBW&L, under the DNREC's instruction, pumped the groundwater
from the shallow aquifer to prevent migration of TRIS into aquifers beneath the site. In
1989, the EPA selected a remedy that requires quarterly monitoring of the shallow
groundwater aquifer for TRIS until the accepted safe level is reached in an estimated four to
five years; annual monitoring of the deeper groundwater aquifer, surface water, and
sediments of the wetland; establishing institutional controls; and reviewing the effectiveness of
the remedy in five years. Groundwater, surface water and sediment monitoring began in 1992.
The State has established the institutional controls by restricting the installation of wells
within 1/2 mile of the site.
Site Facts: A Consent Decree was signed in 1990, in which the potentially responsible
parties will conduct the five-year review of the remedy to confirm that it continues to be
protective of human health. The Consent Decree was recognized by the courts in April 1991,
at which time deadlines for the review were established.
Environmental Progress
By providing an alternative municipal water source and by limiting the future use of the
groundwater until the cleanup levels have been reached, the potential for exposure to
hazardous materials at the New Castle Spill site has been reduced while continued monitoring
of groundwater, surface water, and sediments is underway.
Site Repository
Delaware Dept. of Natural Resources & Environmental Control, Superfund Branch,
715 Grantham Lane, New Castle, DE 19720
NEW CASTLE SPILL 33 March 1992
-------
NEW CASTLE
STEEL PLANT
DELAWARE
EPA ID# DED980705255
Site Description
EPA REGION 3
New Castle County
Near the Delaware River in the
City of New Castle
Other Names:
Deemer Steel Company
For 80 years, Deemer Steel used a 3-acre landfill to dispose of its process wastes. Until the
plant closed in 1987, workers dumped foundry sands, slag, coke, iron oxide scale, baghouse
dust, and metal scrap into two disposal areas separated by a drainage channel that runs to
the Delaware River. Regulations in 1980 indicated that the baghouse dust was a hazardous
waste because of unacceptable levels of cadmium, chromium, and lead. The site was placed
on the NPL in 1982 because of potential groundwater contamination. Since 1982, it has been
determined that baghouse dust does not pose a serious health threat; therefore, it is no
longer classified as a hazardous waste by the EPA. Although metals associated with the site
have entered soils, sediments, surface water, and groundwater, the EPA has determined that
contamination levels at the site are not threatening and do not require cleanup actions. Also,
a number of the metals of concern including cadmium, chromium, and lead exhibited
naturally-occurring higher concentrations than downgradient concentrations.
Site Responsibility: This site was addressed through
Federal, State, and potentially
responsible parties' actions.
NPL LISTING HISTORY
Proposed Date: 12/01/82
Final Date: 09/01/83
Deleted Date: 03/17/89
Threats and Contaminants
The groundwater, sediments, soil, and surface water were contaminated with low
levels of heavy metals including arsenic, chromium, lead, cadmium, and nickel from
the wastes disposed of on site and other nearby, yet undetermined, sources.
However, contamination levels were low and did not pose threats to nearby
residents or the environment.
34
March 1992
-------
Cleanup Approach
Intensive investigations of site conditions showed that the site does not pose a threat to
people or the environment.
Response Action Status
Entire Site: After years of data collection and study, including an intensive
investigation undertaken by the Deemer Steel Company, both the EPA and the
State determined that this site does not constitute a threat to human health or the
environment. Therefore, it was determined that no cleanup actions were required to clean up
the site.
Environmental Progress
Because the site studies have indicated that site contamination does not pose a risk to people
or the environment, the EPA, in conjunction with the State, deleted the New Castle Steel
Plant site from the NPL in 1989.
Site Repository
Information is no longer available.
NEW CASTLE STEEL PLANT
35
March 1992
-------
SEALAND
LIMITED
DELAWARE
EPA ID#DED981035520
EPA REGION 3
New Castle County
Mount Pleasant
Site Description
Operations at the 2-acre Sealand Limited site began in 1971, when Adams Laboratory rented
the property from Conrail, Inc. to operate a rendering plant. In 1979, the owner reportedly
cleaned up the property after its tenant abandoned the plant. The property remained unused
until it was rented by the Sealand Limited and Oil Industry in 1982 to operate a waste oil
recycling plant. The operation accepted coal tar, gas tar, and ink oil wastes, allegedly for
recycling, and stored them on site in tanks and drums. When the tenants abandoned the
facility in 1983, the site contained 22 storage tanks, a boiler house, mixing chambers, pressure
vessels, several hundred 55-gallon drums containing assorted creosote-related chemicals, and
a 10,000-gallon wooden storage tank. A State investigation in 1983 revealed that the wooden
tank and numerous drums were leaking. Analyses of the tanks, drums, and soil detected
polycyclic aromatic hydrocarbons (PAHs), creosotes, solvents, and other toxic organic
compounds. A combined State and EPA study in 1984 showed contaminants in an on-site
monitoring well. However, investigations completed in 1991 showed that groundwater is not
contaminated. The area is primarily agricultural and residential. Private wells within 3 miles of
the site provide drinking water to an estimated 1,000 people.
Site Responsibility: This site is being addressed through
Federal and potentially responsible
parties' actions.
NPL LISTING HISTORY
Proposed Date: 06/16/88
Final Date: 08/30/90
Threats and Contaminants
Low levels of PAHs, creosotes, solvents, and other toxic compounds from the
former recycling operation were found in on-site soils. However, because of the
emergency actions undertaken by the EPA, soil contamination is now within
acceptable health standards and does not pose a risk to individuals who may come
into contact with the soil.
36
March 1992
-------
Cleanup Approach
The site is being addressed through emergency actions; further investigations showed that no
other cleanup actions are required.
Response Action Status
Emergency Actions: In 1983, in response to the imminent threat to human
health, the EPA removed 240,800 gallons of coal tar, 320 drums, and 80 cubic
yards of solid waste. Workers transported the hazardous materials to an
EPA-approved facility, cleaned the storage tanks, and capped the site with a layer of clay and
topsoil to keep rainwater and runoff from spreading pollutants.
Entire Site: Under EPA oversight, the parties potentially responsible for the site
contamination conducted an intensive study of the nature and extent of site
contamination, which was completed in 1991. The study showed that because of
the emergency actions undertaken by the EPA, soil quality is now within acceptable levels.
Site Facts: In December of 1988, the EPA and 15 potentially responsible parties entered
into an Administrative Order on Consent. Under the terms of the Order, the potentially
responsible parties agreed to conduct investigations to determine the nature and extent of
contamination at the site.
Environmental Progress
By removing contaminated materials from the Sealand Limited site, the EPA eliminated the
risk to area residents and the environment. Site investigations conducted by the potentially
responsible parties under EPA monitoring following this action have shown that the site is
safe. No further cleanup activities are necessary at the site.
Site Repository
Appoquinimink Public Library, 218 North Broad Street, Middletown, DE 19709
SEALAND LIMITED 37 March 1992
-------
STANDARD
CHLORINE OF
DELAWARE, INC.
DELAWARE
EPA ID# DED041212473
EPA REGION 3
New Castle County
Delaware City
Site Description
The 46-acre Standard Chlorine of Delaware, Inc. site manufactures chlorinated benzenes and
was listed on the NPL due to a 1981 benzene spill from a railroad tanker car onto the
property. An additional spill occurred in 1986; 569,000 gallons of various volatile organic
compounds (VOCs) spilled after a 375,000-gallon tank of VOCs split open, collapsed, and
damaged three nearby tanks of VOCs, causing the latter tanks to partially spill. About
152,000 people draw groundwater from public and private wells within a 3-mile radius of the
site. Approximately 30 people reside within a mile of the site.
Site Responsibility: This site is being addressed through a
combination of Federal, State, and
potentially responsible parties' actions.
NPL LISTING HISTORY
Proposed Date: 09/01/85
Final Date: 07/01/87
Threats and Contaminants
Chlorobenzenes from spilled material have been found in the groundwater, soil,
and surface water. People may be exposed to the chemicals by direct contact with
contaminated soil or accidental ingestion of contaminated soil or water. Wetlands
near the site also may be threatened by contamination migrating from the spill
areas.
38
March 1992
-------
Cleanup Approach
This site is being addressed in two stages: emergency actions and a long-term remedial phase
focusing on cleanup of the entire site.
Response Action Status
Emergency Actions: The Delaware Department of Natural Resources and
Environmental Control (DNREC) and Standard Chlorine Co. took the following
emergency actions in response to the 1986 spill: (1) excavated a drainage ditch;
(2) built a filter fence along the mouth of the wetland coves; (3) performed pre-excavation
sampling and constructed an earthen dike to isolate the upper portions of the wetland from
contaminants; (4) excavated contaminated sediments upstream of the dike; and (5) built a
basin to trap contaminated sediments in tidal areas of the cove (between the dike and the
filter fence).
Entire Site: Under State order, the parties potentially responsible for the site
contamination are conducting an intensive study of the effect the spill has had on
local groundwater quality, soil, and wetland contamination. The investigation will
explore the nature and extent of the contamination and will identify the best strategies for
cleanup. The study is scheduled for completion in 1993.
Environmental Progress
Emergency actions undertaken by the DNREC and Standard Chlorine Co. have reduced the
risk of exposure to contamination at the site. After a study is completed by the potentially
responsible parties, final cleanup actions will begin at the Standard Chlorine of Delaware, Inc.
site.
Site Repository
Delaware Department of Natural Resources & Environmental Control, Superfund Branch,
715 Grantham Lane, New Castle, DE 19720
STANDARD CHLORINE OF DELAWARE, INC. 39 March 1992
-------
SUSSEX COUNTY
LANDFILL NO. 5
DELAWARE
EPA ID# DED980494637
Site Description
EPA REGION 3
Sussex County
Laurel
The inactive 37 1/2-acre Sussex County Landfill No. 5 operated from 1970 until 1979. It
accepted municipal wastes and, according to a 1978 Congressional report, an unknown
quantity of various volatile organic compounds (VOCs). Wastes were deposited in the ground
below the water table, threatening groundwater. In 1986, the EPA detected several organic
chemicals and solvents in five on-site monitoring wells. The landfill overlies the Columbia
Formation, which is connected to and recharges the Manokin Aquifer. Together, the two
provide drinking water to people within 3 miles of the site. A private well is located 1,000 feet
from the site. Public and private wells within 3 miles of the site provide drinking water to an
estimated 5,700 people and irrigate 5,100 acres of cropland.
Site Responsibility: This site is being addressed through a
combination of Federal, State, and
County actions.
NPL LISTING HISTORY
Proposed Date: 06/16/88
Final Date: 10/04/89
Threats and Contaminants
Five groundwater monitoring wells showed contamination from VOCs, including
benzene and vinyl chloride, from former disposal practices. Possible health threats
include drinking or coming in direct contact with the contaminated groundwater.
Bioaccumulation of contaminants in locally raised livestock and crops is a threat if
contaminated groundwater is used for watering or irrigation.
Cleanup Approach
This site is being addressed in a single long-term remedial phase focusing on cleanup of the
entire site.
40
March 1992
-------
Response Action Status
Entire Site: The landfill was closed by the Delaware Department of Natural
Resources and Environmental Control (DNREC) in 1979. The DNREC installed
monitoring wells on the site as a part of the closure plan. In 1984, the DNREC
conducted a preliminary assessment, which indicated that a leachate plume extended 400 to
500 feet dowigradient of the site. In 1984, the EPA inspected the site and detected elevated
levels of VOCs in the groundwater. Several more wells have been installed in the vicinity of
the landfill and are monitored on a regular basis by Sussex County as part of the
requirements of an agreement between the County and DNREC. In addition, some domestic
wells are monitored; low levels of VOC contamination have been found in one well just north
of the site. An intensive investigation of the site began in 1991. The County will investigate
the nature and extent of groundwater contamination and will recommend cleanup strategies
for the site. The study is expected to be completed in late 1993.
Site Facts: The County and the DNREC have entered into an agreement to establish a
groundwater management program near the landfill. The County will monitor on-site wells
and adjacent domestic wells regularly. In March 1991, an Administrative Order for a site
investigation was signed by Sussex County and the EPA.
Environmental Progress
The EPA evaluated the Sussex County Landfill No. 5 and determined that the site does not
currently pose an immediate threat to nearby residents. By closing the landfill, the State has
reduced threats posed by the site while investigations and cleanup activities are planned.
Site Repository
Not established.
SUSSEX COUNTY LANDFILL NO. 5 41 March 1992
-------
TYBOUTS CORNER
LANDFILL
DELAWARE
EPA ID# DED000606079
Site Description
EPA REGION 3
New Castle County
10 miles south of Wilmington
Tybouts Corner Landfill was constructed in a sand and gravel pit located in northern
Delaware, 10 miles south of Wilmington and 4 miles west of the Delaware River. The main
landfill area is about 47 acres and is located near the confluence of Pigeon Run Creek and
Red Lion Creek. The fill ranges from 5 to 40 feet thick. Between 1968 and 1971, this
privately owned landfill accepted both municipal and industrial wastes, including volatile
organic compounds (VOCs) and various other organic and inorganic chemicals. Tybout's
Corner was built without a clay liner or other impervious material below the fill, and no clay
cap was placed on top of the fill after it was abandoned. EPA studies have revealed that two
shallow aquifers beneath the site are contaminated. About 42 homes and facilities surround
the entire landfill property and most of these have wells that draw from the aquifers
contaminated by the site. Some of the homes are less than 100 feet from the landfill. A
public water supply line was put into service for those homes that draw water from the
contaminated aquifers. In addition, the landfill is located in an area of extensive groundwater
development, both for municipal supplies and large industrial facilities. The possibility for
contaminating the upper hydrologic zone of the Potomac Formation, an important regional
aquifer, exists.
Site Responsibility:
This site is being addressed through
Federal and potentially responsible
parties' actions.
NPL LISTING HISTORY
Proposed Date: 10/01/81
Final Date: 09/01/83
Threats and Contaminants
Local drinking water wells and soils are contaminated with VOCs and other
organic compounds from former disposal practices. Surface water is contaminated
with hazardous organic and inorganic substances. Ingesting or coming into direct
contact with contaminated water or soil may threaten the health of people in the
area.
42
March 1992
-------
Cleanup Approach
This site is being addressed in two stages: immediate actions and a long-term remedial phase
focusing on source control and groundwater cleanup.
Response Action Status
Immediate Actions: The EPA installed a fence in 1982. Between 1984 and
1986, the EPA extended the public water lines to provide service to all 42
residences and facilities surrounding the landfill. The EPA repaired and
reconstructed the security fence around the site and posted warning signs in 1987.
Source Control and Groundwater Cleanup: The selected remedies for this
site are organized into two phases. Phase 1: Source Control includes excavating
all municipal and industrial wastes, as well as contaminated subsoils in the west
fill, and consolidating with the main fill; capping the consolidated main fill northern area with
a multi-layered cap to prevent rainwater from washing away contaminants; installing a slurry
wall and system of interceptor wells; implementing a health and safety plan; and establishing a
monitoring program. Phase 2: Groundwater Cleanup will consist of pumping and treating, or
otherwise disposing of, the area of contaminated groundwater off site in the upper hydrologic
zone of the Potomac Formation. If disposal is called for, it will occur either on site or off site
at a local sewage treatment plant. Restrictions to prevent use of contaminated groundwater
will be applied. The EPA began designing the remedy in 1988; the potentially responsible
parties took over responsibility for the design in 1989. Cleanup activities are scheduled to
begin in 1992 upon completion of these technical specifications.
Environmental Progress
With the construction of a fence around the site to limit access and the provision of a safe
drinking water source to affected residents and businesses, the EPA has made the Tybouts
Corner Landfill site safer while it awaits further cleanup activities.
Site Repository
New Castle Public Library, 424 Delaware Street, New Castle, DE 19720
TYBOUTS CORNER LANDFILL 43 March 1992
-------
TYLER
REFRIGERATION
PIT
DELAWARE
EPA ID# DED980705545
EPA REGION 3
Kent County
Smyrna
Site Description
From 1952 to 1969, Tyler Refrigeration, located on a 3-acre parcel of land, used solvents to
degrease and clean refrigeration equipment, and dumped the spent solvents, paint room
wastes, and sludges into two unlined disposal pits. In the 1970s, Clark Equipment Company
excavated the pit to a depth of 20 feet, filled it in, capped it with 6 inches of topsoil and clay,
and planted vegetation. The site is now occupied by Metal Masters, an active manufacturer
of commercial kitchen equipment. Public access is unrestricted, but most of the old pit's
surface area has been paved. In 1982, the EPA detected elevated levels of three solvents in
the soils. Since 1977, trichloroethylene (TCE) and trichloroethane have been detected in
Smyrna's municipal wells. The State believes that the Tyler pit is a likely contributor to this
pollution, although there may be other sources, since TCE has not been found in on-site soils
or groundwater. About 6,700 people within 3 miles of the site get their drinking water from
wells, both municipal and private. Approximately 4,700 people rely on the public water
supplies; 60 homes stand within 1/4 mile of the site, with the closest being within 300 feet.
Site Responsibility:
This site is being addressed through
Federal and potentially responsible
parties' actions.
NPL LISTING HISTORY
Proposed Date: 06/01/86
Final Date: 02/21/90
Threats and Contaminants
The on-site groundwater is contaminated with volatile organic compounds (VOCs)
including trichloroethane from former process wastes. On-site monitoring wells also
have detected elevated levels of chromium in groundwater samples. The soil
contains elevated levels of VOCs, including toluene, dichloroethane, and
trichloroethane. Accidental ingestion of or direct contact with contaminated soil or
groundwater from the existing private wells may pose a health threat.
44
March 1992
-------
Cleanup Approach
This site is being addressed in two stages: an immediate action and a long-term remedial
phase focusing on groundwater cleanup at the site.
Response Action Status
continues to operate.
Immediate Action: To remove VOC contamination in the municipal wells, the
town improved the efficiency of its air-stripping process and added an activated
carbon filtration unit to its water treatment system. The treatment system
Groundwater: The parties potentially responsible for the site contamination
began an intensive study of the groundwater contamination at this site in 1991.
This investigation will reveal the nature and extent of the pollution and pinpoint
the best cleanup strategies. It is scheduled for completion in late 1993; once completed, the
EPA will select the final remedies for cleanup of the groundwater and other contaminated
areas.
Site Facts: A Consent Order was signed by Clark Equipment Company and the EPA in
1991, under which the company agreed to perform an investigation of site contamination.
Environmental Progress
By improving the air-stripping process and adding an activated carbon filtration unit to its
water treatment system, the Town of Smyrna is reducing the threat of VOC contamination
from municipal wells, making the public water supply safer while investigations to select the
final remedy are conducted at the Tyler Refrigeration Pit site.
Site Repository
Smyrna Public Library, 107 South Main Street, Smyrna, DE 19977
TYLER REFRIGERATION PIT 45 March 1992
-------
WILDCAT LANDFI
DELAWARE
EPA ID# DED980704951
Site Description
EPA REGION 3
Kent County
21/2 miles south of Dover,
adjacent to the St. Jones River
From 1962 until 1973, a landfill operated on 44 acres of the 84-acre Wildcat Landfill site,
situated next to the St. Jones River in Dover, 1/2 mile west of the Dover Air Force Base
(AFB) NPL site. The privately owned landfill accepted municipal and industrial waste until it
was closed under a State order for numerous violations of a State permit. Operators dumped
wastes into wetlands and frequently left them uncovered. Groundwater is contaminated with
heavy metals, organics, and low levels of polychlorinated biphenyls (PCBs). Open and empty
metal drums, tires, solid latex, and municipal trash were scattered over the surface of the site.
A 3-acre pond, which collects surface drainage from the western half of the landfill, lies
immediately to the west of the landfill. Monitoring of drinking water wells in 1987 showed no
contamination, but contaminant levels in groundwater underneath and downgradient of the
site were at levels of public health concern. The St. Jones River, which borders the site, is
used for recreational fishing and boating. Two trailer parks, the Dover AFB housing complex,
and 12 residences are located within 1/2 mile of the site. Local residents rely on groundwater
for drinking water supplies and are served by public or private wells. There are 24 active wells
within 1/2 mile and 16 within 1,000 feet of the site.
Site Responsibility: This site is being addressed through
Federal actions.
NPL LISTING HISTORY
Proposed Date: 12/01/82
Final Date: 09/01/83
Threats and Contaminants
The groundwater was contaminated with chlordane, a pesticide, and volatile
organic compounds (VOCs) including methylene chloride and xylene. On-site
surface water, leachate, soils, and sediments contained PCBs and chlordane.
Accidentally ingesting contaminated groundwater, surface water, soil, sediments, or
contaminated aquatic organisms or coming into direct contact with contaminated
groundwater, surface water, soil, sediments, and air may have threatened the
health of people at or near the site. The State has issued a health advisory on fish
caught from the St. Jones River.
46
March 1992
-------
Cleanup Approach
The site is being addressed in two long-term remedial phases focusing on source control and
pond cleanup.
Response Action Status
Source Control: The remedy selected to clean up contamination from the
landfill includes: restricting development of the site and preventing installation of
drinking water wells on or near the site; grading, covering, and seeding on-site
areas where direct risks of contact with contaminants have been identified; removing and
disposing of drums; replacing two private domestic wells adjacent to the site with
uncontaminated wells drilled deeper into the aquifer; and monitoring groundwater. All
cleanup activities were completed in 1992. Monitoring of the groundwater continues to
ensure the long-term effectiveness of the remedy.
Pond Cleanup: The remedy for the 3-acre pond that drains the western half of
the landfill featured filling in the existing pond and building a new shallow pond
southeast of the landfill. These activities were completed in 1992.
Environmental Progress
Removal of site contaminants, placement of restrictions on the use of groundwater in the
area, the replacement of contaminated wells, and the pond cleanup have been completed and
eliminated the threat of exposure to hazardous materials from the Wildcat Landfill site.
Site Repository
Delaware Department of Natural Resources & Environmental Control, Superfund Branch,
715 Grantham Lane, New Castle, DE 19720
WILDCAT LANDFILL
47
March 1992
-------
GLOSSARY
Terms Used in the NPL Book
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. A table of common
toxic chemicals found at NPL sites, their sources, and their potential threats is located
on page G-15
Acids: Substances, characterized by low pH
(less than 7.0), that are used in chemical manu-
facturing. Acids in high concentration can be
very corrosive and react with many inorganic
and organic substances. These reactions possi-
bly may create toxic compounds 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). This type of Order is not signed by the
PRPs and does not require approval by a judge.
Aeration: A process that promotes breakdown
of contaminants in soil or water by exposing
them to air.
Agency for Toxic Substances and Dis-
ease Registry (ATSDR): The Federal
agency within the U.S. Public Health Service
charged with carrying out the health-related
responsibilities of CERCLA.
Air Stripping: A process whereby volatile
organic chemicals (VOCs) are removed from
contaminated material by forcing a stream of air
through the contaminated material in a pressur-
ized 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.
Applicable or Relevant and Appropriate
Requirements (ARARs): Federal, State, or
local laws which apply to Superfund activities at
NPL sites. Both emergency and long-term
actions must comply with these laws or provide
sound reasons for allowing a waiver. ARARs
must be identified for each site relative to the
characteristics of the site, the substances found
at the site, or the cleanup alternatives being
considered for the site.
G-1
-------
GLOSSARY
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 percent or
more of the drinking water of an area.
Artesian (Well): A well made by drilling into
the earth until water is reached, which, due to
internal pressure, flows up like a fountain.
Asbestos: A mineral fiber that can pollute air
or water and is known to cause cancer or
asbestosis when inhaled.
Attenuation: The naturally occurring process
by which a compound is reduced in concentra-
tion over time through adsorption, degradation,
dilution, 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
removing 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, forming salts.
Berm: A ledge, wall, or a mound of earth used
to prevent the migration of contaminants.
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 contaminated
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 else-
where.
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 ground-
water 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 organic
G-2
-------
GLOSSARY
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 Environmen-
tal Response, Compensation, and Liability Act].
Characterization: The sampling, monitoring,
and analysis of a site to determine the extent and
nature of toxic releases. Characterization
provides the basis for acquiring the necessary
technical information to develop, screen, ana-
lyze, and select appropriate cleanup techniques.
Chemical Fixation: The use of chemicals to
bind contaminants, thereby reducing the poten-
tial 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 inter-
changeably 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. Also, 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 communication
with the public. The goals of community
relations programs include creating an under-
standing of EPA programs and related actions,
assuring public input into decision-making
processes related to affected communities, and
making certain that the Agency is aware of, and
responsive to, public concerns. Specific com-
munity relations activities are required in
relation to Superfund cleanup actions [see
Comment Period].
Comprehensive Environmental Re-
sponse, 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 together.
Confined Aquifer: An aquifer in which
groundwater is confined under pressure that is
significantly greater than atmospheric pressure.
G-3
-------
GLOSSARY
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, or the costs incurred by the govern-
ment that the parties will reimburse, and the
roles, responsibilities, and enforcement options
that the government may exercise in the event of
non-compliance by potentially responsible
parties. If a settlement between the EPA and a
potentially responsible party includes cleanup
actions, it must be in the form of a Consent
Decree. A Consent 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 structure,
typically in a pond or a lagoon, to prevent the
migration of contaminants into the environment.
Contaminant: Any physical, chemical,
biological, or radiological material or substance
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 radioac-
tive materials into the environment.
Cooperative Agreement: A contract
between 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 pre-
serving operations and produced by distilla-
tion of tar, including polycyclic aromatic
hydrocarbons and polynuclear aromatic
hydrocarbons [see PAHs and PNAs]. Con-
taminating 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 embank-
ment.
Decommission: To revoke a license to
operate and take out of service.
Degradation: The process by which a chemi-
cal is reduced to a less complex form.
Degrease: To remove grease from wastes,
soils, or chemicals, usually using solvents.
Deletion: A site is eligible for deletion from
the NPL when Superfund response actions at the
site are complete. A site is deleted from the
NPL when a notice is published in the Federal
Register.
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.
G-4
-------
GLOSSARY
Dike: A low wall that can act as a barrier to
prevent a spill from spreading.
Dioxin: An organic chemical by-product of
pesticide manufacture which is known to be one
of the most toxic man-made chemicals.
Disposal: Final placement or destruction of
toxic, radioactive, or other wastes; surplus or
banned pesticides or other chemicals; polluted
soils; and drums containing hazardous materials.
Disposal may be accomplished through the use
of approved secure landfills, surface impound-
ments, land farming, deep well injection, or
incineration.
Downgradient: A downward hydrologic
slope that causes groundwater to move toward
lower elevations. Therefore, wells downgradi-
ent of a contaminated groundwater source are
prone to receiving pollutants.
Ecological Assessment: A study of the
impact of man-made or natural activity on living
creatures and their environment
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 facili-
ties.
Emulsifiers: Substances that help in mixing
materials that do not normally mix; e.g., oil and
water.
Endangerment Assessment: A study
conducted 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; 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 Recov-
ery].
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. In this
volume, the feasibility study is referred to as a
site study [see also Remedial Investigation].
G-5
-------
GLOSSARY
Filtration: A treatment process for remov-
ing solid (participate) 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.
General Notice Letter: [See Notice Letter].
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 and willing-
ness to perform a site study or cleanup.
Groundwater: 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. Hazardous waste
possesses at least one of four characteristics
(ignitability, corrosivity, reactivity, or toxic-
ity), or appears on special EPA lists.
Heavy Metals: Metallic elements; with high
atomic weights, such as arsenic, lead, mercury,
and cadmium. Heavy metals are very hazardous
even at low concentrations and tend to accumu-
late in the food chain.
Herbicide: A chemical pesticide designed to
control or destroy plants, weeds, or grasses.
G-6
-------
GLOSSARY
Hot Spot: An area or vicinity of a site contain-
ing exceptionally high levels of contamination.
Hydrocarbons: Chemical compounds that
consist entirely of hydrogen and carbon.
Hydrology: The properties, distribution, and
circulation of water.
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 controlled
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 precipita-
tion (rain or snow) or from application of
wastewater 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 sub-
stances of mineral origin, not of basic carbon
structure.
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,
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 or incor-
porate 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 chemi-
cal landfills are disposal sites for hazardous
waste. They are designed to ininimize the
chance of release of hazardous substances into
the environment [see Resource Conservation
and Recovery Act].
Leach, Leaching [v.t.J: The process by
which soluble chemical components are dis-
solved and carried through soil by water or
some other percolating liquid.
G-7
-------
GLOSSARY
Leachate [n]: The liquid that trickles through
or drains from waste, carrying soluble compo-
nents from the waste.
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
complexity, site cleanup activities can be
separated into several of these phases.
Long-term Response Action: An action
which requires a continuous period of on-site
activity before cleanup goals are achieved.
These actions typically include the extraction
and treatment of groundwater and monitoring
actions.
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, con-
taminants, water, or other liquids through porous
and permeable soils or rock.
Mill Tailings: [See Mine Tailings].
Mine Tailings: A fine, sandy residue left from
rnining 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 controlling
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 which
groundwater flows and the types and amounts of
contaminates present.
National Priorities List (NPL): The
EPA's list of the most serious uncontrolled or
abandoned hazardous waste sites identified
for possible long-term cleanup under Super-
fund. The EPA is required to update the NPL
at least once a year.
Natural Attenuation: [See Attenuation].
Neutrals: Organic compounds that have a
relatively neutral pH, complex structure and,
due to their organic bases, are easily absorbed
into the environment. Water is the most
commonly known neutral, however, naphtha-
lene, pyrene, and trichlorobenzene also 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 potentially respon-
sible parties, although the EPA may undertake
certain investigatory and planning activities.
G-8
-------
GLOSSARY
The 60-day period may be extended if the EPA
receives a good faith offer from the PRPs
within that period. [See also Good Faith Offer].
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, hydrogen, 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 may be 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.
Pesticide: A substance or mixture of sub-
stances intended to prevent, destroy, or repel any
pest. If misused, pesticides can accumulate in
the foodchain and contaminate the environment.
Petrochemicals: Chemical substances
produced from petroleum in refinery operations
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 poison-
ous.
Physical Chemical Separation: The
treatment process of adding a chemical to a
substance 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 determine
its ability to clean up specific contaminants.
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 movement
of the groundwater is influenced by such factors
as local groundwater flow patterns, the character
of the aquifer in which groundwater is con-
tained, 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.
G-9
-------
GLOSSARY
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 creosotes 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 caulking
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 Substances Control Act
Polynuclear Aromatic Hydrocarbons
(PNAs): PNAs, such as naphthalene, and
biphenyls, are a group of highly reactive organic
compounds that are a common component of
creosotes, which can be carcinogenic.
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 concentra-
tions 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 associated with a Superfund site who
may be liable for the cost of remedying the
release of hazardous substances. This may
include owners or operators of the site or trans-
porters who disposed of materials at the site.
PRPs may admit liability, or liability may be
determined by a court of law. PRPs may sign a
Consent Decree or Administrative Order on
Consent to participate in the site cleanup without
admitting liability.
Precipitation: The removal of solids from
liquid waste so that the solid and liquid portions
can be disposed of safely; the removal of
particles from airborne emissions. Electro-
chemical 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 information
about a known or suspected waste site or release
to determine if a threat or potential threat exists.
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 envi-
ronment. Radon, the gaseous form of radium,
decays to form alpha particle radiation, which
cannot be absorbed through skin. However, it
can be inhaled, which allows alpha particles to
affect unprotected tissues directly and thus cause
cancer. Radiation also occurs naturally through
the breakdown of granite.
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.
G-10
-------
GLOSSARY
Record of Decision (ROD): A public
document 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 con-
struction 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 contamina-
tion at a Superfund site, establish the criteria
for cleaning up the site, identify the prelimi-
nary alternatives for cleanup actions, and
support the technical and cost analyses of the
alternatives. The remedial investigation is
usually done with the feasibility study. In this
volume, the remedial investigation is referred
to as a site study [see also Feasibility Study].
Remedial Project Manager (RPM): The
EPA or State official responsible for oversee-
ing cleanup actions at the 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 without
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 re-
maining in the environment after a natural or
technological process has taken place, e.g.,
the sludge remaining after initial wastewater
treatment, or the particulates remaining in air
after the air passes through a scrubber.
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
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 the
store waste.
Runoff: The discharge of water over land
into surface water. It can carry pollutants
from the air and land and spread contaminants
from its source.
Scrubber: An air pollution control 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.
G-11
-------
GLOSSARY
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 the 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 neces-
sary for choosing and designing cleanup mea-
sures 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 subsurface
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 smelters
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
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 ap-
proaches: dissolving or suspending them in the
wash solution for later treatment by conven-
tional methods, and concentrating them into a
smaller volume of soil through simple particle
size separation techniques [see Solvent Extrac-
tion].
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
hazardous constituents. Mobility is reduced
through the binding of hazardous constituents
into a solid mass with low permeability and
resistance to leaching.
G-12
-------
GLOSSARY
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
attracting substances. It is used in many
pollution control systems.
Special Notice Letter: [See Notice Let-
ter].
Stillbottom: Residues left over from the
process of recovering spent solvents.
Stripping: A process used to remove volatile
contaminants from a substance [see Air Strip-
ping].
Sumps: A pit or tank that catches liquid
runoff for drainage or disposal.
Superf und: 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 re-
leases of hazardous substances that may endan-
ger public health, welfare, or the environment.
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, including
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 Wetlands].
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
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 contaminated
areas and, therefore, are not prone to contamina-
tion 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.
G-13
-------
GLOSSARY
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 poten-
tially toxic chemicals are used as solvents,
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 pollut-
ants 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.
G-14
-------
GLOSSARY
Some Common Contaminants at NPL Sites
Contaminant
Category
Example
Chemical Types
Sources
Potential Health
threats*
Heavy Metafe
Volatile Organic
Compounds
Polyshforinated.
RacBatfon
Arsenic, Barium, Beryllium,
Cadmium, Cobalt, Copper,
Chromium, Lead, Manga-
nese, Mercury, Nickel,
Silver, Selenium, Zinc
Trichloroethylene (TCE),
Perchloroethylene (PCE),
Acetone, Benzene,
Ketone, Methyl chloride,
Toluene, Vinyl Chloride,
Dichlorethylene
Chlordane, DDT 4-4, DDE,
Heptachlor, Aldrin, Endrin,
Atrazine, Dieldrin, Toxa-
phene
Polyaromatic hydrocar-
bons (PAHs), Polynuclear
aromatics (PNAs),
Phenolic Tars, Pentachlo-
rophenol (PCP)
Radium-226, Radon,
Uranium-235, Uranium-
238
Electroplating, batteries,
paint pigments, photogra-
phy, smelting, thermom-
eters, fluorescent lights,
solvent recovery
Solvents and degreasers,
gasoline octane enhanc-
ers, oils and paints, dry
cleaning fluids, chemical
manufacturing.
Agricultural applications,
pesticide and herbicide
production
Electric transformers and
capacitors, insulators and
coolants, adhesives,
caulking compounds,
carbonless copy paper,
hydraulic fluids.
Wood preserving, fossil
fuel combustion
Mine tailings, radium
products, natural decay of
granites
Tumors, cancers, and kidney,
brain, neurological, bone and
liver damage
Cancers, kidney and liver
damage, impairment of the
nervous system resulting in
sleepiness and headaches,
leukemia
Various effects ranging from
nausea to nervous disorders.
Dioxin is a common by-product
of the manufacture of pesti-
cides and is both highly toxic
and a suspected carcinogen.
Cancer and liver damage.
Cancers and skin ulcerations
with prolonged exposure
Cancer
Sources:
Toxic Chemicals—What They Are, How They Affect You (EPA, Region 5)
Glossary of Environmental Terms (EPA, 1988)
'The potential for risk due to these contaminants is linked to a number of factors; for example, the length and level of exposure
and environmental and health factors such as age.
*U.S. G.P.O.:1993-341-835:81028
G-15
------- |