United States
Environmental Protection
Agency
Prepared by the Office of
Water Regulations and Standards
and the Office of Solid Waste and
Emergency Response in conjunction
with the Dioxin Strategy Task Force
November 28, 1983
Washington, DC 20460
&EPA Dioxin Strategy
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United States Environmental Protection Agency
DIOXIN STRATEGY
Prepared by the Office of Water Regulations and Standards
and the Office of Solid Waste and Emergency Response
in conjunction with the Dioxin Strategy Task Force
November 28, 1983
Washington, DC 20460
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EPA's DIOXIN STRATEGY
November 28, 1983
TABLE OF CONTENTS
EXECUTIVE SUMMARY
Part 1 - Introduction 1
Part 2 - EPA1 s Dioxin Strategy 6
Study Tiers 6
Implementation of the Strategy 7
Field Sampling 12
Analytical Issues 13
Assessment of Data 16
Regulatory Initiatives 18
Remedial Actions at Contaminated Sites 19
Health and Environmental Effects of 2378-TCDD 20
Other Dioxins and Dioxin-like Compounds 22
Coordination 24
Community Relations 24
Part 3 - Interim Guidance for Tiers 1 and 2 26
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EXECUTIVE SUMMARY
The strategy presented here provides a framework under which
the U.S. Environmental Protection Agency (EPA) will 1) study
the extent of dioxin contamination and the associated risks to
humans and the environment, 2) implement or compel necessary
clean-up actions at contaminated sites, and 3) further evaluate
regulatory alternatives to prevent future contamination, as well
as disposal alternatives to alleviate current problems.
EPA will be investigating and taking appropriate response or
enforcement actions at production, disposal, and processing sites
where pesticides (including herbicides) contaminated with dioxin
were or are being handled. In addition, the Agency will be
sampling other possibly contaminated sites as well as the ambient
environment throughout the United States for the presence of
dioxin. This overall investigation is in response to concerns
raised by the increasing number of instances when environmental
contamination by chlorinated dioxins has been documented. EPA
will also continue its evaluations of human health risks associated
with exposure to chlorinated dioxins and of disposal and destruc-
tion methods.
Although there are 75 different chlorinated dioxins, 2,3,7,8-
tetrachlorodibenzo-p-dioxin (2378-TCDD) is the one of primary
concern because it is the most toxic dioxin isomer, with the
potential of presenting significant health and disposal issues.
The 2378-TCDD isomer is known to be a contaminant of 2,4,5-
trichlorophenol (2,4,5-TCP) when 2,4,5-TCP is made from tetra-
chlorobenzene. 2,4,5-TCP is used in the manufacture of various
phenoxy herbicides, including 2,4,5-trichlorophenoxyacetic acid
(2,4,5-T) and Agent Orange, a defoliant herbicide used in Vietnam.
The emphasis on 2,4,5-TCP and its derivatives is based on the
fact that in nearly every place where 2378-TCDD has been found
in the environment, it can be associated, if not definitively
linked, to 2,4,5-TCP production or disposal sites.
To facilitate implementation of the strategy, EPA has defined
the following study tiers based on decreasing potential for
2378-TCDD contamination:
Tier 1 - 2,4,5-TCP production sites and associated waste
disposal sites.
Tier 2 - Sites (and associated waste disposal sites) where
2,4,5-TCP was used as a precursor to make pesticidal
products.
Tier 3 - Sites (and associated waste disposal sites) where
2,4,5-TCP and its derivatives were formulated into
pesticidal products.
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Tier 4 - Combustion sources.
Tier 5 - Sites where pesticides derived from 2,4,5-TCP have
been and are being used on a commercial basis.
Tier 6 - Certain organic chemical and pesticide manufacturing
facilities where improper quality control on certain
production processes could have resulted in the
formation of 2378-TCDD contaminated products waste
streams.
Tier 7 - Control sites where contamination from 2378-TCDD is
not suspected.
The strategy calls for investigating and taking any necessary
response or enforcement actions at tier 1 sites and, eventually,
at tier 2 sites. Sites in tiers 3-6 will also be studied to
determine the probability of contamination at these types of
sites. Sampling at sites in tiers 1-6 will initially consist of
a screening of areas most likely to be contaminated to determine
if 2378-TCDD is present at the site. If it is, further sampling
may include all media (air, water, soil, stream sediments, fish
tissue) which are appropriate to define the extent of contamination
and health risk. Sampling in tier 7 will be done in two phases. In
the first phase, EPA will collect multi-media samples at a number of
control areas (e.g., towns, sections of cities, rural areas)
selected throughout the United States. During the second phase
EPA will sample fish (and other aquatic organisms) at selected
stations throughout the United States. All sampling done under
this strategy will follow prescribed analytical protocols.
Another important aspect of the strategy is to determine the
potential health and environmental risks from exposure to 2378-TCDD
in different media. EPA, in conjunction with other appropriate
federal agencies such as the Veteran's Administration (VA) and the
various constituent agencies of the Department of Health and Human
Services (HHS), (e.g., the Centers for Disease Control (CDC),
the Food and Drug Administration (FDA), and the National Institutes
for Occupational Safety and Health (NIOSH)), will undertake
research to understand more fully the specific effects of 2378-
TCDD on humans and other species, and to develop techniques to
determine actual risk given different levels of environmental
contamination.
While investigations into the extent of human health and
environmental risks from contamination by 2378-TCDD proceed,
EPA will also be evaluating different alternatives for containing
and eventually disposing of soils and wastes contaminated with
2378-TCDD. These alternatives include various methods of securing
contaminated soil and preventing leachate runoff or percolation,
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extraction of dioxin from soils, and incineration or photolysis
for destruction of dioxins.
Finally, the strategy lists a number of research activities
to define the potential human health and environmental risks
from dioxin isomers other than 2378-TCDD and other "dioxin-
like" chemicals. These activities include 1) assessing the
toxicity of the other isomers, 2) determining their specific
sources, 3) evaluating their environmental fate and transport
properties, 4) developing exposure and risk assessments based
on the above information, and 5) recommending appropriate control
measures. To assist in these activities, the sampling program
for 2378-TCDD includes provisions to analyze for other dioxin
isomers and "dioxin-like" chemicals when appropriate to the
situation or the sampling site.
Regulatory Activities
EPA's efforts to regulate dioxin in the environment began in
1973 when the Agency instituted proceedings to cancel the
registration of the pesticide 2,4,5-T, based primarily on its
contamination by 2378-TCDD. (Earlier, the U.S. Department of
Agriculture had limited uses of 2,4,5-T on food crops.) EPA
terminated the cancellation proceedings in 1974, partly because
the analytical chemistry techniques available at the time were
not capable of measuring 2378-TCDD in food or the environment at
the low levels which could pose a hazard. The Agency has since
significantly improved its analytical capabilities. In 1978,
EPA initiated the Rebuttable Presumption Against Registration
(RPAR) process against pesticide products with 2,4,5-T. In
1979, based on a study of miscarriage rates in Alsea, Oregon
(where 2,4,5-T had been sprayed on forest land) and extensive
laboratory data demonstrating that 2,4,5-T, silvex, and/or 2378-
TCDD cause cancer and adverse reproductive effects in test animals,
EPA ordered an emergency suspension of 2,4,5-T and silvex use on
forests, rights-of-way, pastures, home gardens, turf, and aquatic
vegetation. Other uses were still being evaluated under the
RPAR process. Dow Chemical Company appealed the suspension in
federal court and lost. In 1980, an EPA administrative law
judge began consolidated cancellation hearings on the suspended
and nonsuspended uses of 2,4,5-T and silvex. These hearings
were postponed in 1981 to allow Dow and EPA to concentrate on
settlement discussions.
Other programs have also been involved in regulatory activities
related to dioxin. Under the Clean Water Act (CWA), 2378-TCDD
is listed as one of the 65 compounds and classes of compounds
which EPA is required to control in industrial effluents. To
date, no national discharge regulations have been issued for
2378-TCDD, primarily because it has not been detected in effluents.
The only time it has been measured in effluents was when EPA's
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Region 5 personnel measured it at the 50 parts per quadrillion
level in the Dow effluent. (Analytical problems may be one of
the reasons why 2378-TCDD was not otherwise detected.) EPA is
working with the State of Michigan on developing limitations for
Dow's permit. Under the Clean Air Act, EPA is currently assessing
the health impacts of 2378-TCDD as a hazardous air pollutant.
As an interim step to control the disposal of any wastes con-
taining 2378-TCDD (defined as wastes resulting from the production
of 2,4,5-TCP or its pesticide derivatives, or substances produced
on equipment that was previously used for the production of 2,4,5-
TCP or its pesticide derivatives), EPA in 1980 promulgated a rule
under the Toxic Substances Control Act (TSCA) which requires any
persons intending to move or otherwise dispose of these wastes
to notify EPA of its plans 60 days prior to initiating any action.
This allows EPA to review the plans and ensure that the wastes
are properly managed. In 1983, EPA proposed to regulate wastes
containing any tetra-, penta-, and hexachlorodibenzo-p-dioxins
under the Resource Conservation and Recovery Act (RCRA). This
action will cover a wider range of wastes and is designed to
ensure that no future sites are contaminated with dioxin wastes.
As this dioxin strategy is implemented and the data are
assembled, analyzed, and reviewed, various regulatory options
to prevent or control future 2378-TCDD contamination will be
evaluated. Control options will include new applications of
existing regulations as well as development of new regulations.
Such actions as RCRA waste stream listings, CWA Section 307(a)(2)
•listings, TSCA Section 6 rules, and Clean Air Act hazardous
pollutant listings, and alternative management options (e.g.,
prohibiting certain dioxin-containing wastes from land disposal),
will be evaluated and recommendations to initiate regulatory
actions will be made by appropriate program offices. Programs
initiating regulatory actions should use the Dioxin Management
Task Force as a steering committee for regulatory development.
Management and Implementation of the Strategy
The Assistant Administrator (AA) for the Office of Solid
Waste and Emergency Response (OSWER) under the direction of the
Deputy Administrator is responsible for implementing the strategy
including the periodic reporting of progress to EPA's Deputy
Administrator. OSWER will directly manage the investigations
and responses for sites in tiers 1 and 2. The Office of Water
(OW) has been delegated responsibility for the overall management
of the studies within tiers 3-7. Within tiers 3-7, individual
program offices will be responsible for developing study plans
relating to their programs; for example, the Office of Air, Noise
and Radiation (OANR) will prepare the study plan for tier 4.
The AA for OSWER will have review and approval authority for any
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policy or plans developed by other EPA offices that are implementing
delegated portions of the strategy. OSWERwill also have oversight
responsibility for the preparation of external correspondence,
testimony and public statements.
This strategy reflects what is currently known about dioxins
and presents a general plan for implementation. Specific work
plans for the various elements of the strategy are to be prepared
by the appropriate program officers in conjunction with the
Regions. The actual detailed sampling plans for sites in tiers
3-7 (exclusive of tier 4) will be prepared by the Regional offices
in conjunction with the States and will be reviewed by the appro-
priate program office. Sampling plans for sites in tiers 1 and
2 will be prepared by the Regional offices in conjunction with
the States, CDC and NIOSH when appropriate. The individual work
plans are to be more specific than the strategy and the detailed
sampling plans are, by nature, unique to each sampled' site; they
reflect what is known at the time of their preparation and the
availability of resources. As time goes on and more information
is developed, the work plans and the sampling plans are expected
to reflect the assimilation of new information and go through
perhaps several changes. Thus, the strategy and the elements of
implementation (e.g., work plans, sampling plans, disposal
guidance) will evolve as new information becomes available.
OSWER has issued detailed interim guidance (see Part 3 of
this document) to the regional offices on how to proceed with
investigations of the tier 1 and tier 2 sites. This guidance
differentiates between the actual production sites (tiers 1 and
2) and the associated transportation, treatment, storage, and
disposal sites (referred to as tiers 1A and 2A in the guidance).
The basic approach outlined in the guidance is first to collect
detailed information on each of the sites from EPA and. State
data bases and, if necessary, from site visits and employee
interviews. Initially, any new field investigations (screening)
will be limited to tier 1 sites; new sampling work at sites in
tiers 1A, 2, and 2A will be initiated after the information
being collected has been evaluated by OSWER. Where the need
for a clean-up response is identified, initial efforts are to be
directed at getting potentially responsible parties to take
appropriate action. If prompt and appropriate clean-up is not
assured by responsible parties, EPA will respond in a manner
consistent with the National Contingency Plan and the Regional
work plans or seek to compel response. The priority for taking
either enforcement or response actions at dioxin sites will be
determined by evaluating the seriousness of the problem at the
site relative to the problem at all other sites whether they
include dioxin or not.
Funding for investigations and response actions for sites in
tiers 1 and 2 will come from the Comprehensive Environmental
Response, Compensation, and Liability Act (CERCLA), while funding
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for studies related to tiers 3-7 will come from a special
appropriation for what is referred to as "The National Dioxin
Study". If contamination is detected at sites in tiers 3-7,
the data will be forwarded to OSWER for further evaluation, in
accordance with the interim guidance.
Implementation of the strategy will require close coordi-
nation with a number of other federal agencies, including FDA,
CDC, NIOSH, and others. OSWER is responsible for ensuring that
proper coordination takes place. One of the key issues requiring
interagency coordination: is health and environmental effects
research. OSWER, in conjunction with EPA's Office of Research
and Development (ORD), is responsible for developing an initial
list of research needs.
Background - Toxicology
Most of the available toxicological information on dioxins
is for the 2378-TCDD isomer, which has caused lethal and toxico-
logical effects in laboratory animals at lower levels than
any other man-made chemical. However, both the lethal dose levels
and the toxicological effects vary considerably among different
animal species. EPA's Cancer Assessment Group regards 2378-TCDD
as both an initiator and a promoter of cancer; this declaration
is based on animal studies rather than data from humans. Based
on its carcinogenic potency, EP.A estimates that cancer risks to
individuals exposed to soils or fish contaminated by 2378-TCDD
could be significant under certain exposure conditions which are
probably not widespread. Thus, estimates of national aggregate
risks cannot be made with any degree of accuracy until more data
on exposure are collected.
Background - Sources
A number of the dioxins, including 2378-TCDD, are formed as
inadvertent byproducts during the manufacture of certain organic
chemicals, particularly chlorinated phenols. The 2378-TCDD
isomer is formed during the production of 2,4,5-trichlorophenol
(2,4,5-TCP), which is a basic chemical feedstock used to make
several pesticide products including 2,4,5-trichlorophenoxyacetic
acid (2,4,5-T), silvex, hexachlorophene (a germicide), ronnel,
and erbon. EPA scientists estimate that 80 to 95 percent of the
2378-TCDD which is formed during the production of these chemicals
ends up in the waste still bottoms from the toluene distillation
step of 2,4,5-TCP production. Most manufacturers disposed of
these wastes by placing them in landfills or incinerating them;
however, some of the still bottoms may have been injected into
disposal wells or transported for disposal by contractors. Other
possible releases to the environment of 2378-TCDD from the 2,4,5-
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TCP manufacturing process include wastewaters generated by contact
cooling and product separation, and air emissions caused by the
venting of reaction vessels.
In addition, the 2,4,5-TCP product itself could have been
contaminated with 2378-TCDD, particularly if it was manufactured
prior to the mid 1970's when reaction conditions began to be
more carefully controlled. Product contamination, therefore,
implicates sites where 2,4,5-TCP was used to make pesticide
products and, to a lesser extent, sites where those pesticide
products were formulated for final uses. Finally, sites where
these pesticide products were used could also be contaminated.
At the present time there are no known producers of 2,4,5-
TCP in the United States; however, more than a dozen facilities
have produced it in the past and may still be using contaminated
equipment. A somewhat larger number of facilities were involved
in manufacturing 2,4,5-TCP based pesticides, and perhaps hundreds
of facilities were involved in formulating these pesticides.
(Part of EPA's strategy will be to refine the inventories of
these facilities.) Finally, although past uses were more wide-
spread, current uses of these pesticides are limited primarily
to Arkansas and Louisiana rice fields, western rangeland, sugarcane
fields in Florida, and certain rights-of-way as a result of the
1979 suspensions. However, it is difficult to predict the extent
of future use of 2,-4,5-T and silvex even in light of the 1979
suspensions.
Combustion sources such as municipal and industrial waste
incinerators and accidental transformer fires (where the trans-
formers contained a mixture of PCBs and chlorobenzenes) have
been implicated as sources of 2378-TCDD and other dioxins.
Generally, levels of the. 2378-TCDD isomer from these sources
have been relatively low; however, there is a potential for
increased risk to populations in the vicinity of these sources.
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PART 1
INTRODUCTION
Overview
This strategy provides a framework for actions that EPA, in
coordination with other Federal and State agencies, will be
taking in response to concerns about health risks from exposure
to dioxin contamination in .the United States. Since dioxin
contamination may exist in soil, water, and air, several programs
within EPA, at both the headquarters and regional levels, are
involved in this strategy; States are likewise actively involved.
There are two primary reasons which have led to the development
of this strategy: (1) to provide a systematic technical approach
in the investigation of sites, including both chemical production
facilities and waste sites, suspected of beitjg contaminated with
dioxin; and (2) to determine the extent of environmental contami-
nation pursuant to an FY 84 congressional appropriation specifi-
cally earmarked to conduct a "National Dioxin Study". Without
this strategy, EPA's response to dioxin issues might possibly
become "piecemeal," uncoordinated, and inconsistent, with
priorities being established by special interest groups rather
than from a perspective which considers the total situation.
There are 75 different chlorinated dioxins, divided into
8 homologues (groups), each with different physical and chemical
properties depending on the number and location of chlorine atom
substitutions. One of 22 isomers with four chlorine atoms,
2,3,1i8-tetrachlorodibenzo-p-dioxin (2378-TCDD), is of primary
concern because of its extreme toxicity in animals.
Much information has already been collected on dioxins. Infor-
mation is still being collected, and response efforts are being
ta.ken to reduce human exposure to dioxins. However, unless
these efforts are part of a systematic national plan, inconsistent
actions could occur, and information collected for one purpose
might not be available to others who need it.
The EPA dioxin strategy provides for intensive study of
locations potentially contaminated with the most toxic of the
dioxin isomers, 2378-TCDD (about which the most is known, both
on toxicology and sources). The other dioxin isomers will also
be evaluated to determine whether they merit the same intensive
investigation. As a first step in this process, much incidental
information will be collected on these isomers as part of the
2378-TCDD effort.
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In addition to the investigation and response activities
called for in the strategy, the 2378-TCDD study will address five
questions: 1) Where does it come from? 2) Where does it go?
3) What are the levels of concern? 4) Once it is in a medium
at levels of concern, what can be done about it? and 5) What
can be done to prevent -it from getting into the media?
This strategy does not suggest that 2378-TCDD is the only
toxic pollutant the Agency must address. It may not even be
the most critical in terms of environmental and human health
effects. Therefore, it is important that the individual program
offices and the Regions implementing this strategy carefully
recognize that their efforts on this contaminant may impact
resources available for other problems and that resource decisions
affecting this strategy are to be made jointly with the program
offices and the Regions.
Approach
To implement this strategy, EPA has established seven cate-
gories (or tiers) for investigation and/or study ranging from
the most probable tier of contamination (2,4,5-TCP production
and waste sites) to the least. The functional components of
implementation include:
a. a comprehensive investigation leading to clean-up at the
most contaminated sites;
b. a national study to learn more about the extent of
environmental contamination; and
c. prevention -"of future contamination through development
of control actions and regulations.
This strategy addresses the most toxic of the dioxin isomers,
2378-TCDD, and lays out a plan to evaluate the other dioxin isomers
to determine whether the same type of intensive investigation is
necessary. Some initial screening for other isomers will be done
at some of the sites, including control sites, being investigated
for 2378-TCDD.
One of the most important elements of this strategy is that
it be coordinated with other Federal agencies and with States,
as well as within EPA. The dioxin problem cannot be adequately
addressed without active coordination of all these groups. For
example, FDA sets action levels and consumption advisories for fish
and other consumables, CDC issues health advisories under CERCLA,
and NIOSH sets limits on exposure in the workplace. In addition,
the Federal Emergency Management Agency (FEMA) coordinates the
relocation of people during response actions under CERCLA, and
VA has developed a large body of expertise from dealing with
veterans on the Agent Orange issue.
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States in conjunction with the Regional offices will continue
to have a major responsibility in investigating and responding
to individual sites in tiers 1 and 2 as they do under CERCLA.
The Agency hopes to involve each of these groups so that
everyone can benefit from the others' experience, knowledge,
expertise, and resources.
2378-TCDD Questions
1. Where does it come from? and 2. Where does it go?
For these two questions, EPA has set up seven categories
(or tiers) for study. These include former production sites,
waste disposal sites, incineration sites, formulation sites,
etc. Under the overall direction of the Assistant Administrator
for Solid Waste and Emergency Response (OSWER), individual offices
will evaluate the sources with which they have the greatest
familiarity.
3. What are the levels of concern?
National criteria or action levels for 2378-TCDD have not
yet been established. The respective program offices are currently
reviewing three dioxin hazard assessment documents (ambient water
quality criteria for 2378-TCD.D; health -assessment document for
dioxins; and health and environmental effects profile for tetra-,
penta-, and hexachlorodibenzo-p-dioxins) being prepared by ORD
to determine the implications these documents have on the dioxin
strategy. Site-specific assessments have been made (the 1 ppb
action level for soil at Times Beach, Mo.), however, despite the
lack of national criteria in order to assess the potential risk
to humans at contaminated sites. In addition, the FDA has estab-
lished a "level of concern" for 2378-TCDD in fish.
Until such time that further action levels are developed, EPA's
OSWER, in conjunction with ORD, is responsible for developing a
list of health and environmental effects research needs. Included
among these needs are standardization of hazard assessment infor-
mation, establishment of exposure scenarios, and development of
a nomograph for converting from 2378-TCDD levels of contamination
in all environmental media to estimates of upper risk limits
for a variety of exposure scenarios. This type of information
is imperative for the development of action levels.
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4. Once it is in a medium at levels of concern, what can
be done about it?
Available techniques are quite limited at this time. EPA's
OSWER, in conjunct ion. with ORD and the Dioxin Disposal .Advisory
Group, will be responsible for pilot testing the more promising
disposal/destruction techniques.
5. What can be done to prevent it getting into the
environment?
Since there is no known current production of 2,4,5-TCP in the
United States, future production of 2378-TCDD is likely to be
limited to much smaller quantities from such sources as hazardous
waste incinerators, transformer fires, and possibly municipal
incinerators. These assumptions will be tested during the study.
Under the appropriate regulations (FIFRA, TSCA), EPA will collect
information on any future production of 2,4,5-TCP or its deriva-
tives that are used for pesticidal purposes. EPA is committed to
regulatory actions that go beyond existing controls if the results
of this strategy indicate that additional controls are needed.
Other Dioxin isomers
The Office of Solid Waste (OSW) has the. lead -responsibility
for developing a program to assess the other dioxin isomers and
"dioxin-like" compounds. Activities to be defined in the program
include: 1) determining the specific sources of other dioxin
isomers, 2) assessing their toxicity, 3) evaluating their environ-
mental fate and transport properties, 4) developing exposure and
risk assessments based on the above information, and 5) recom-
mending appropriate control actions. Implementation of this
program is contingent upon available resources.
Comparison of Risks
In comparing the risks posed by 2378-TCDD with the risks
attributed to other pollutants, it is important to identify and
understand the components of risk. Simply stated, risk is a
function of exposure to a chemical and the likelihood of some
kind of harmful effect. One of the harmful effects can be cancer
if it can be demonstrated that the chemical causes cancer in
either laboratory animals or humans. The risk from carcinogens
is usually expressed in quantitative terms as a probability
value based on an exposure level. Other harmful effects may
include, for example, heart disease and emphysema, although
quantitative risk estimates for these kinds of effects are not
usually expressed in probabilistic terms.
It is also important to discern between individual risks and
aggregate (population) risks. Concern about individual risk
focuses on the effect of a pollutant on increasing the risk to
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particular individuals, without regard to the number of individuals
involved. Concern about aggregrate risk couples individual risks
with the number of individuals involved -, and thus deals with the
number of cancer cases which can be prevented.
The derivation of cancer risks requires an assessment of the
chemical's potency and the amount of the chemical to which the
animal is exposed. Thus, understanding or quantifying exposure
is a necessary component in defining risk. Comparing the quanti-
tative risks associated with 2378-TCDD with other chemicals is
confounded because of the lack of good exposure information. We
are, therefore, left with a comparison that is qualitative based
on relative carinogenic potency, the amount estimated to be in
the environment, and its behavior.
The quantities of 2378-TCDD produced and released are much
smaller than other pollutants of concern. On the other hand, its
toxicity and carcinogenic potency are much greater. Thus, for
example, the release of 2678-TCDD *in past years is estimated to
be about 30,000,000 times less than the release of benzene,
4,000,000 times less than carbon tetrachloride, and 130,000 times
less than PCBs. On the other hand, carcinogenic potency of 2378-
TCDD, based on animal data, is estimated to be 17,000,000 times
greater than benzene, 5,000,000 times greater than carbon tetra-
chloride, and 100,000 times greater than PCBs. The bioaccumu-
lation potential of 2378-TCDD is 20,000 times greater than that
of benzene, 6,000 times greater than carbon tetrachloride, and
4 times greater than PCBs. Also, compared to benzene, 2378-TCDD
is very persistent in the environment.
Based on what is- known about 2378-TCDD release and behavior
(i.e., low levels of release, very persistent, and extremely
potent), it is believed that -risks to some individuals may be
significant; however, the risks may not be widespread. Conse-
quently, the aggregate risk to 2378-TCDD would probably not
match that of such a ubiquitous pollutant as benzene (from gaso-
line) , a pollutant with a large level of release and a high
potential for widespread human exposure, which is not very
persistent and is not a very potent carcinogen when compared to
2378-TCDD. -
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PART 2
EPA'S DIOXIN STRATEGY
Study Tiers
1. The following tiers (or categories of sources) are hereby
defined based on a decreasing potential for 2378-TCDD contami-
nation; th6y will be addressed by this strategy as described in
the succeeding sections:
Tier 1 - Current (if any) and former sites of 2,4,5-TCP
production including sites where wastes were dis-
posed. The number of tier 1 production sites is
estimated to be about 20; the total number of
sites to be investigated (production sites plus
was£e disposal sites) is not presently known.
Tier 2 - Sites (current and former) where 2,4,5-TCP was
used as a precursor to make another chemical product
(e.g., hexachlorophene production sites, 2,4,5-T,
and silvex) including sites where wastes were
disposed. The number of tier 2 production sites
is estimated to be about 30, exclusive of sites
where wastes were disposed.
Tier 3 - Sites (current and former) where 2,4,5-TCP and its
derivatives (e.g., silvex) were formulated into 'a
pesticidal product. An example would be a site
where 2,4-D and 2,4,5-T were mixed to make Agent
* Orange. - Tier 3 also includes sites where formu-
lating wastes were disposed.
Tier 4 - Combustion sources such as: incineration of hazardous
and muncipal waste (including sewage sludge); wire
reclamation facilities; internal combustion engines;
home heating units (e.g., wood burning stoves);
industrial, fossil-fuel fired boilers; and inadver-
tent combustion sources such as PCB-transformer
fires. The number of potential sites in this tier
is estimated to be in the millions.
Tier 5 - Sites where 2378-TCDD contaminated pesticides have
been used or are being used on a commercial basis.
These areas include certain rights-of-way, rice
fields of Arkansas and Louisiana, pastures and
and western rangeland, sugarcane fields in Florida
and Louisiana, certain aquatic sites, and forests
(e.g., Pacific northwest). In addition, animals
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animals which have been grazed on treated land and
fish from treated waterbodies may contain 2378-TCDD
residues.
Tier 6 - Sites where production of certain other .organic
chemicals or pesticides may have resulted, through
improper quality control, in the formation of 2378-
TCDD. The total number of production sites in this
tier is probably less than one hundred.
Tier 7 - Control sites selected to evaluate the extent of
dioxin contamination in areas where manufacturing
or extensive use of 2378-TCDD contaminated chemicals
has not occurred, information from these sites will
be used: (a) to compare with sites where 2378-TCDD
is a known contaminant and (b) to establish "back-
ground" levels of 2378-TCDD.
Implementation of the Strategy
Management and Funding
2. The AA for OSWER is responsible for implementing the over-
all strategy; he will report directly to the Deputy Administrator
for purposes of this strategy.
3. The AA for OSWER will be assisted by three coordinating
groups: (1) the Dioxin Management Task Force (DMTF) , (2) the Dioxin
Chlorinated Dioxin Work Group (CDWG) and (3) its sub-group, the
Disposal Advisory Group (DDAG) formerly called the Dioxin Task
Force. Membership on groups (2) and (3) is currently set; member-
ship on" the DMTF shall be Office Director (OD) level individuals
from Headquarters and Division Director level individuals from
the Regions.
4. The extent of Headquarters and Regional membership on the
DMTF shall be determined by the AA for OSWER.
5. The Dioxin Management Task Force will assist the AA for
OSWER in implementing the overall strategy and function as a
steering committee dealing with policy and resource issues. The
Chlorinated Dioxin Work Group will continue to provide technical
expertise as necessary and the Dioxin Disposal Advisory Group
will continue to make technical recommendations about site-specific
clean-up and disposal/destruction options.
6. Efforts conducted in tiers 1 and 2 will be managed directly
by OSWER and funded under CERCLA authority.
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7. Efforts conducted in tiers 3 thru 7 have been delegated
to OW, in conjunction with appropriate program offices. In
particular, OANR-will manage the development of a study plan for
tier 4.
8. Management of tiers 1 and 2 will result in a comprehensive
assessment of sites under CERCLA authority leading possibly to
identification of responsible parties, enforcement actions and
site clean-up.
«
9. The program in tiers 3 thru 7 constitutes "The National
Dioxin Study" ; it is a study to learn more about the nature of the
problem by sampling respresentative facilities and sites. It is
'not as comprehensive an investigation as that planned for tiers
1 and 2 which are thought to represent over 80 percent of the
problem in terms of levels of contamination.
10. Implementation of efforts in these seven tiers will
proceed in a concurrent, parallel fashion. While the initial
efforts in tiers 3 thru 7 will take two years, the comprehensive
assessment of sites in tiers 1 and 2 will extend beyond two years,
particularly at sites where enforcement actions and clean-up
options are complex. In addition, any necessary followup actions
at sites in tiers 3 thru 7 where contamination is found are
likely to extend beyond two years.
Tiers 1 and 2
11. Sites (both manufacturing facilities and waste dis-
posal sites) in tiers 1 and 2 will be investigated following the
attached guidance (Part 3 of this document) issued by OSWER.
«
12. The interim guidance subdivides tiers 1 and 2 into:
tier 1A and tier 2A which include the transport, treatment,
storage, and disposal handlers or sites used by tier. 1 and tier
2 facilities. A primary objective of the interim guidance is to
set forth a process for defining the dimension of the universe
to be investigated in these tiers.
13. A second objective of this interim guidance is to make
certain that the Agency's limited sampling resources are initially
focused on the most serious sites. Regions are therefore directed
to place primary emphasis on tier 1 sites, and later, on tier 1A
sites. New sampling at tiers 1A, 2, and 2A sites should be
delayed, where it is not inconsistent with prior commitments,
until the size of the universe for both tiers (1 and 2) are
better defined.
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14. The interim guidance directs Regional activities through
several phases: an information collection phase, a field investi-
gation phase and a response phase. Also included in the interim
guidance are sections which provide guidance on community rela-
tions, enforcement procedures, and guidance on disposal alter-
natives.
Tiers 3 thru 6
15. Because of the large number of sites to be investigated
for 2378-TCDD in these tiers, sampling at every site is not
practicable. One of the first steps will be to list, using avail-
able-data, all facilities/sites in these tiers. Preliminary
lists for tiers 3 and 6 have been developed by OW in conjunction
with the other program offices and the Regions. These lists
cannot be completed in final form until the results from infor-
mation collection forms have been received and all facilities
can be assigned to their proper tier.
16. The field investigations to be done at, tiers 3 thru 6
over the next two years (FY 84 and 85) will be from a selected
sample of sites based on a sample frame developed by OW, in
conjunction with the Regional offices and EPA program offices
(e.g., OANR). The development of the sampling frame for tier 4
— combustion sources — will be managed by OANR, with assistance
from ORD. They will be supported by OSWER for designing the
sampling frame for hazardous waste incinerators and OPTS for
evaluating municipal waste incinerators.
17. The initial sampling to be done at tiers 3 thru 6 will
be funded through an FY 84 appropriation of $4 million which has
commonly been referred to as "The National Dioxin Study"; "this
appropriation is directed to OW, which will allocate resources
to the Regions and program offices based on anticipated sampling
requirements.
18. OW, in conjunction with the other program offices and
the Regions, has prepared a preliminary work plan availble for
review for the "The National Dioxin Study". This plan will
describe the "universe" of sites in each of the tiers, the basis
for site selection, tentative schedules, and arrangements for
sample control.
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19. In developing the sampling plan for tiers 3, 5 and 6, it
is anticipated that multi-media samples will be taken at sampled
sites, including samples of water, aquatic sediments, fish, soils,
groundwater, vegetation, air, and waste streams (liquid, gaseous,
solid) as appropriate. Once the preliminary sampling plan has
•been reviewed, the Regions will then develop detailed sampling
plans (e.g., number of samples per media) for the initial sites
to be sampled by March 1, 1984. Once the detailed plans are
reviewed by the appropriate program office, the Regions will be
responsible for initiating field sampling.
20. Sampling at facilities in tier 4 — combustion sources —
will include source sampling for air emissions and ambient air
and will draw upon information 'already available from previous
sampling efforts (e.g., OPTS source sampling of municipal incine-
rators). Ambient samples of other media (e.g., fish, vegetation,
and soil) may be taken as needed. OANR in conjunction with the
Regions is responsible for developing the sampling plan at tier 4
facilities.
21. Funds available for "The National Dioxin Study" are to be
used primarily to establish whether sites in tiers 3 thru 6 are
contaminated with 2378-TCDD. The object of the study is to
learn more about 2378-TCDD contamination at sites in these tiers.
If 2378-TCDD is detected at a site during the study, the data
will be forwarded to. OSWER for further•evaluation. Also, there
may be reasons, such as public requests and requests from state
governments, to sample sites in tiers 3 thru 6 that are not part
of the sample design. Any activity at these sites will be in
accordance with the interim guidance and coordinated with the
appropriate program office.
22. It must be emphasized that, although sites "found to be
contaminated in tiers 3 thru 6 will be referred to OSWER for
possible CERCLA action, such referrals do not necessarily imply
immediate response, remedial actions or enforcement. These
referrals will have to be considered along with all of the sites
in tiers 1 and 2 based on a schedule for response developed by
OSWER.
23. While the Office of Water has been delegated the overall
lead in implementing "The National Dioxin Study", the interpre-
tation of results and decision to take actions (e.g., remedies,
and control actions) is the responsibility of the respective
program offices.
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Tier 7 - Control Sites
24. Tiers 1 thru 6 represent sites or areas where contami-
nation with 2378-TCDD is either known or suspected. A portion of
the samples to be taken at these tiers will be ambient samples of
suspected contaminated media, such as aquatic sediments, soils,
fish, vegetation and groundwater. These samples will be useful
in establishing the extent of outward migration of 2378-TCDD from
a source that is shown to be contaminated.
25. EPA believes it is equally important to assess the extent
of environmental contamination of 2378-TCDD by taking ambient
samples at sites not suspected of being directly influenced by
known sources of 2378-TCDD. This may be considered an attempt
to establish what many call a "background" concentration, and
also serves to provide discrete data which address the general
perception that 2378-TCDD contamination may be more widespread
than previously documented. A portion of the special appropriation
for "The National Dioxin Study" is specifically earmarked for
this work.
26. Pursuant to this, the Office of Water, in conjunction
with Regions and Headquarters program offices, will develop a
sampling plan designed to determine the extent of 2378-TCDD
contamination at various control sites.
27. The sampling in tier 7 will include two phases. The
first phase will be to collect a number of soil, fish and stream
sediment samples at about 20 control areas. These areas could
be towns, sections of cities, or rural areas. These sites will
fall into five categories: 1) chemical production areas (other
than areas in tiers 1-6), 2) other industrial areas, 3) commercial/
residential areas, 4) agricultural areas, and 5) undisturbed
areas. The initial candidate list of sites will be developed by
OW based, in part, on recommendations by the Regions. Once the
actual sites have been chosen, detailed sampling plans will be
developed by the Regions in conjunction with the States.
28. The second phase of sampling in tier 7 will be to sample
organisms in streams located throughout the United States, open
waters of the Great Lakes, and estuarine waters. Stations will
be selected which characterize conditions throughout the drainage
basins. A preliminary list of stations has been sent to the
Regions for their review. After review and final selection of
stations, the Regions will be responsible for collecting the
specimens. Initial sampling will be whole fish composites of the
same species, preferably bottom feeders. If significant contami-
nation is detected, analyses of fillets and stream sediments may
be warranted.
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29. Detailed guidance (e.g., site selection, sampling and
preservation methods) for tier 7 sampling will be issued by OW
after the "National Dioxin Study" plan has been reviewed. It is
anticipated that this guidance will be available by December 31,
1983.
30. Control sites which show 2378-TCDD contamination will
be evaluated by the Office of Water and the Regions to establish,
if possible, the source of contamination. The data will also be
forwarded to OSWER for additional evaluation.
31. This strategy acknowledges the current proposal by OPTS
to measure dioxin (and furan) levels in human adipose tissue,
although at this time this effort is judged to be outside the
scope of sampling and funding pursuant to "The National Dioxin
Study". Nonetheless, EPA recognizes the value of this proposal,
therefore appropriate funding mechanisms will be investigated by
OPTS.
Field Sampling
32. Field sampling for all tiers, except tier 4, will be
implemented through the EPA Regional offices.
33. Field investigations at sites in tiers 1 and 2 shall
continue to use, as necessary, the Superfund contractors as well
as the Technical Enforcement Support (TES) contract. Wherever
possible, responsible parties may be involved in conducting
field investigations at the direction of the Regional Office in
conjunction with States.
34. Field investigations at sites in tiers 3., 5, 6, and 7
will be conducted by the Regional Offices employing those
mechanisms they deem appropriate. For example, Regions may use
contractors, their own Regional personnel, or may arrange for
the States to perform the field sampling. Whatever choice is
made, the individual sampling plans to be developed by the Regions
for tiers 3, 5, 6, and 7 are to indicate the arrangements for
field sampling.
35. Sampling at sites in tier 4 shall be arranged by OANR.
They may use contractors or a combination of contractors and
Regional/State personnel.
36. Whenever it is judged to be necessary, appropriate health
and safety precautions shall be used during field sampling. This
may require the use of personal respirators and other similar
equipment. The individual sampling plans, prepared by the Regions,
should indicate the need for such equipment.
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37. Arrangements for laboratory analyses will be coordinated
through the "Dioxin- Sample Control Center". This center, for
purposes of this strategy, will combine some of the functions
currently being provided by OSWER's Sample Management Office
(SMO) and OW1s Sample Control Center. The Dioxin Sample Control
Center will also be responsible for: (1) providing documentation
of the analytical methods including procedures for quality control
and quality assurance and (2) entering the results into a central
data system after they have been checked by the Regions and
States. Specific details on these*arrangements will be available
for review by January 15, 1983.
38., This strategy reflects what is currently known about
dioxins and presents a general plan for implementation. Specific
work plans for the various elements of the strategy are to be
prepared by the appropriate program offices in conjunction with
the Regions. In turn, the Regions will prepare detailed sampling
plans unique to each sampling site. Both work plans and sampling
plans will reflect what is known at the time of their preparation
and the availability of resources. As time goes on and more
information is developed, the work plans and the sampling plans
are expected to reflect the assimilation of new information and
go through perhaps several changes. Thus, the strategy and the
elements of implementation (e.g., work plans and sampling plans)
will evolve as new information becomes available.
Analytical Issues.
' Sampled Media
39.
in tiers
soil, stream
Generally, multi-media sampling will be done at sites
i 1 thru 7, including, but not limited to, samples of
, __ream sediments, groundwater, surface water, ambient air,
wastewater discharges, air emissions, fish, and other biological
specimens (e.g., vegetation) as appropriate for the site.
40. The specific media to be sampled will, of course, be
dictated by the type of facility or site in a particular tier.
For example, sampling of waste sites associated with tiers 1 and
2 (tiers 1A and 2A) will likely be limited to soils, groundwater
(if the site is near an aquifer currently used as a drinking
water supply), and surface water, if nearby. Specific sampling
plans, developed by the Regions in conjunction with the States
whenever appropriate, will spell out the types of media to be
sampled.
41. In certain circumstances it may be prudent to composite
or pool samples in order to increase the sampling area without
substantially increasing the number of samples to be analyzed.
Compositing and pooling can, however, dilute the concentration
in the pooled or composited sample, therefore, care must be
used in making this decision.
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Detection Limits
42. Soil samples collected during screening at sites in
tiers 1, 2, 3, 4, and 6 will be analytically measured for 2378-
TCDD using methods that will result in a parts per billion (ppb)
detection level. In certain cases sub-ppb detection limits can
be achieved depending on the sample volume and the extraction
efficiency. Follow-up investigations at contaminated sites may
require soil analyses at the parts per trillion (ppt) detection
limit, depending on the circumstances of contamination and
potential for -human exposure.
43. Soil samples collected at tiers 5 and 7 will be
analytically measured for 2378-TCDD using methods that will
result in a ppt detection level. Since these tiers represent
areas where "background" levels of 2378-TCDD are being evaluated,
ppt level of detection is judged to be necessary.
«.
44. Samples of stream sediments, fish, other biological
specimens (e.g., vegetation) and waste streams (liquid, gaseous,
solid) will be analytically measured for 2378-TCDD using methods
that will result in detection levels in the ppt range.
45. Samples of surface water, groundwater, and ambient air
shall be of sufficient volume to permit parts per quadrillion
(ppq) level of detection. '
Laboratory Resources
46. EPA1s ORD and OPTS will provide analytical services
for all samples collected in tiers 3 thru 7; control of these
samples will be accomplished through OW s Sample Control Center.
The analytical services will be managed by EPA's Environmental
Research Laboratory in Duluth, MN, and will provide analyses of
150 samples per month for two years, the length of the "National
Dioxin Study". . Requirements for ppt and ppq analyses beyond the
two years should be fulfilled by a sufficient number of contract
laboratories that are anticipated to be in a position to do the
required work by that time.
47. ORD will select appropriate sampling and analytical
methods and QA/QC specifications for 2378-TCDD analyses in all
tiers. These methods will be documented by the Dioxin Sample
Control Center and circulated for review by January 15, 1983.
Interim analytical methods and QA/QC procedures for 2378-TCDD
analyses are described in an ORD document dated July 27, 1983.
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48. EPA's OSWER will begin to develop the requirements for
low detection level dioxin analyses, including the necessary
arrangements to certify/qualify contract laboratories and to
provide for contractual mechanisms in order that Regions and
States can have samples processed at the ppt and ppq level beyond
the two-year life of the ORD analytical commitment.
49. The Regions/States can continue to use the National
Contract Lab Program as described in the Interim Guidance (Part
3 of this document) for sampling conducted at tiers 1 and 2 or
they may use the ORD/OPTS analytical services for samples to be
processed at the ppt or lower detection limits. Samples destined
for a contract lab should be controlled through OSWER1s SMO.
During screening investigations, soils are to be measured at the
ppb level of detection, and other samples (e.g., fish, sediments)
are to be measured at the ppt level of detection.
50. Because of the large number of samples to be collected
from tiers 1 through 7, the priorities for analytical work may
at some point become an issue. The basic goal and the function
of the Dioxin Sample Control Center is to make certain that
sampling episodes will be consistent with the analytical pace
and capacity so that samples are processed as quickly as they
are collected. In the event a backlog occurs, samples from the
lower numbered tiers (tiers 1, 2, and 3) take priority.
51. This strategy recognizes that because.'.the number of
potentially contaminated sites has not been enumerated, the total
number of samples to be processed cannot be accurately estimated.
Thus, samples collected from all seven tiers could conceivable
outstrip current analytical capacity. It is important, therefore,
to understand that if this happens, increasing laboratory capa-
bility may require additional resources and time.
Analyses for Other Chemicals
52. Analyses for other chemicals (e.g., other dioxins, furans,
PCB's, chlorophenols) in addition to 2378-TCDD may be appropriate
at certain sites, including control sites (tier 7). While the
National Dioxin Study principally focuses on 2378-TCDD, sampling
and analyses for other chemicals may be reasonable in order to
make cost-effective use of field and laboratory resources.
53. The decision to analyze for other chemicals will be made
on a case-by-case basis by OSWER for sites in tiers 1 and 2 and
the Office of Water in tiers 3 thru 7. Decisions will be made
in conjunction with the Regions and coordinated through the
respective offices. All analytical extracts processed under this
strategy will be held for possible subsequent analysis for other
chemicals and other dioxin isomers.
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54. The analytical service to be provided by ORD of 150
samples per month is based on a scheme whereby tetra-class dioxins
are initially analyzed. Should there be the need to analyze for
other dioxins or other chemicals, the need must first be approved
by the appropriate program office since analyses for other than
tetra-class dioxins will reduce the sample capacity of the ORD
laboratories. For this reason, sufficient sample volumes will
be taken to allow for subsequent analyses of other dioxins,
furans, or other chemicals as appropriate.
55. The sampling plan to be developed by OSWER for the other
dioxin isomers may include some of the same sites that will be
sampled during the National Dioxin Study. Until such time that
the sampling plan for the other dioxin isomers is developed,
duplicate samples should be collected from the sampled sites of
the National Dioxin Study. One sample will be measured for the
tetra-class dioxin isomers and the other sample held for possible
inclusion in the scheme to study the other dioxin isomers.
Assessment of Data
56. The data obtained from sites sampled in tiers 1 thru 7
(exclusive of tier 4) will be assembled by the respective Regions.
The Regions, in conjunction with the program offices, will then
prepare a report for each sampled site which summarizes available
information including the analytical results; analytical results
will be sent directly to the Regions from the Sample Control
Center. This report, to be completed within one month from
receipt of all the analytical data, should also contain recommen-
dations from the Regions on follow-up activities.
57. Reports on sites in tiers 1 and 2 will be forwarded to
OSWER for review, comment, and assessment of follow-up actions.
58. Reports on sites in tiers 3 thru 7 will be forwarded to
OW and OSWER for review and comment. Reports on sites in tier 4
— combustion sources — will be prepared by OANR with assistance
from the Regions where the combustion sites were sampled.
59. Sites in all tiers that are determined to be contaminated
with 2378-TCDD will be further evaluated by OSWER to determine
the need for further sampling and/or response. As stated pre-
viously and emphasized again, referring a site to OSWER does not
necessarily imply immediate response, remedial actions or enforce-
ment. The timing of actions must be consistent with the degree
of contamination and potential health risk of the site when
compared to other contaminated sites.
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60. Whenever it is determined that there is sufficient
sampling to demonstrate that 2378-TCDD contamination constitutes
a potential public risk, the Regions In conjunction with OSWER,
as described in the Interim Guidance, will immediately notify
the appropriate officials including, but not necessarily limited
to, State officials (particularly health officials) and CDC.
61. CDC and FEMA will continue to work through the OSWER
program office as defined in the Executive Order pursuant to
.CERCLA and redelegation agreements pursuant thereto.
62. The Regions are initially responsible for compiling
and reporting the data which will be collected pursuant to this
dioxin strategy. To effectively manage the data and facilitate
the review by the Regions and the program offices, centralization
of the data is essential. Pursuant to this need, EPA's STORET
system will be used to store and retrieve the dioxin data which
will be collected from all tiers. The Dioxin Sample Control
Center will, after first reporting the analytical results to
the Regions, enter the results into STORET. Access to the data
will be limited based on guidelines developed by the Sample
Control Center in conjunction with- the Regions and the program
offices.
63. The development of site-specific response actions or
enforcement at contaminated sites will be managed by OSWER in
conjunction with respective Regions and other Federal/State
agencies involved with the site. If appropriate, the Chlorinated
Dioxin Work -Group and its subgroup, the Dioxin Disposal Advisory
Group shall review disposal/destruction related activities at
these sites.
64. OW in conjunction with the other program offices and
the Regions will assess the extent of 2378-TCDD contamination
in tiers 3 thru 6. The basis for this assessment will be developed
from the information collected at the sampled sites and must be
consistent with the overall sampling frame.
65. OW will also evaluate the data collected at tier 7
sites. This information, plus the site specific information from
sampling tiers 1 thru 6, will be the basis for determining the
extent of environmental contamination of 2378-TCDD. This overall
determination shall be made jointly by OSWER and OW in conjunction
with those program offices that have major assignments in the
strategy and the Regional Offices.
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66. Pursuant to the special appropriation for "The National
Dioxin Study," OSWER and OW in conjunction with the other program
offices and the Regions will prepare a report which documents
the extent of environmental contamination based on the information
obtained pursuant to this strategy. This report shall be forwarded
to the Deputy Administrator and made available to the public by
December 31, 1985.
Regulatory Initiatives
67. As stated previously, this strategy is being developed
to study the extent of dioxin contamination, implement necessary
remedial actions at hazardous sites, and evaluate regulatory
actions to prevent future contamination. EPA has a strong
commitment to regulatory actions if necessary to ameliorate
existing problems or to prevent future ones. The very nature of
2378-TCDD, however, makes regulatory development an especially
difficult process. „
68. EPA is committed to publishing the three dioxin hazard
assessment documents recently reviewed by a peer group of scien-
tists in Cincinnati, OH. While the documents are not regulatory
actions per se, they can have regulatory implications for the
affected program offices. The affected offices are to carefully
evaluate these criteria documents and develop, where appropriate,
regulatory initiatives that are consistent with this dioxin
strategy.
69. As the data are assembled, analyzed, and reviewed, various
regulatory options to prevent or control future 2378-TCDD contami-
nation will be evaluated. Such actions as RCRA waste stream
listings, CWA Section 307(a)(2) action, TSCA Section 6 rules, and
Clean Air Act hazardous pollutant listings, for example, will be
evaluated and recommendations to initiate regulatory actions
will be made by appropriate program offices where the da-ta justify
regulations. Equally important will be the evaluation of current
permit authorities (e.g., underground injection, ocean disposal)
to assess whether changes are necessary. The Agency will explore
utilizing the Dioxin Management Task Force as a steering committee
for regulatory development related to dioxin.
70. On April 4, 1983, EPA through its RCRA program has
proposed adding the following waste streams to EPA's list of
hazardous wastes:
(a) The production and manufacturing use of tri-, tetra-, or
pentachlorophenol and intermediates used to produce their
derivatives;
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(b) The manufacturing use of tetra-, penta-, or hexachloro-
benzenes under alkaline conditions;
(c) The production of materials on equipment previously used
for the production or manufacturing use of materials
listed under (a) and (b) above; and
(d) Discarded unused formulations containing tri-, tetra-,
or pentachlorophenols, or discarded unused formulations
containing compounds derived from these chlorophenols.
Under RCRA, the Agency has broad authority to regulate all
aspects of hazardous waste management (i.e., generation; trans-
portation; treatment/storage/disposal). The proposed rule for
active facilities will impact the response by the Agency to the
contamination sources in each of the tiers.
Remedial Actions at Contaminated Sites .
71. Based on the information obtained and analyzed from sites
sampled in tiers 1 thru 7, short and long-term clean-up strategies
will be implemented or compelled at those sites where dioxin con-
tamination is judged to warrant action. This judgment shall be
made by OSWER with technical assistance from CDC, the Chlorinated
Dioxin Work Group, ORD, the Regions and the affected States. Clean-
up activities w.ill proceed in accordance with the interim guidance
and the National Contingency Plan. The priority for taking
either enforcement or response actions at dioxin sites will be
determined by evaluating the seriousness of the problem at that
site relative to the problem at all other sites whether they
include dioxin or not.
72. Presently, alternatives which appear to be most suitable
for uncontrolled sites are listed below:
A. Secure soil in place — in situ soil fixation, subsurface
perimeter grout curtain, impermeable cap, diversion of
surface runoff, resident relocation from immediate area
and monitoring.
B. Consolidate and secure soil — removal of soil to secure
landfill; or containment of soil in a concrete vault,
possibly on-site.
C. Incineration — following excavation and transportation,
a size reduction process is required before incineration.
D. Solvent Extraction — solvents would be used to extract
dioxin from the soil into a soluble form. Several
different technologies could then be used to destroy
the dioxin.
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73. OSWER, in conjunction with ORD and the Dioxin Disposal
Advisory Group (DDAG), will be responsible for pilot testing the
'more promising disposal/destruction techniques. A specific
research agenda shall be developed by December 20, 1984.
74. Several important questions need to be addressed through
pilot studies before these alternatives can be fully evaluated.
For example, to destroy dioxin, the treatment technology must
first break the dioxin/soil particle bond. In doing so, partially
treated residues, or contaminated materials which may be released
during processing, have the potential to spread contamination.
Therefore, ORD will consider including a sorption/desorption study
on contaminated soils as part of its research agenda to determine
dioxin release rates. While these treatment technologies may
present the ultimate solution to contaminated media, they could
present significant health risks during processing. Thus, during
the pilot testing phase, the potential for further contamination
must be assessed.
75. Based upon the success of the pilot testing phase, OSWER
staff in conjunction with ORD and the DDAG will recommend full
field validation projects to the AA for OSWER. Upon approval, ORD
will implement the full field validation studies in conjunction
with the Region where testing is to occur. Full field validation
work should commence by July 1985.
76. The results of pilot testing and full field validation
will be reported to OSWER. These results will be used to support
specific guidance concerning the alternatives for clean-up given
specific conditions of contamination and exposure. This guidance
will be used in deciding upon final clean-up options at specific
contaminated sites.
Health and Environmental Effects of 2378-TCDD
77. EPA realizes that much remains to be discovered about
the effects of 2378-TCDD on both human health and the environment.
The development of specific action levels is hindered by this
fact. This strategy recognizes that additional work must be done
in this area and the information integrated into an authoritative
view of the risks, including development of action levels associ-
ated with exposure to 2378-TCDD. Delaying the implementation of
this strategy until final action levels are developed, however,
is not believed to be in the best public interest.
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78. Some of the studies to be conducted are short-term in
nature and appropriately managed by EPA; other types of studies
are longer-term and are beyond the purview of EPA. Thus, inter-
agency coordination in this area is essential. For purposes of
intra-agency coordination, OSWER, in conjunction with ORD and the
program offices, will develop a list by February 15, 1984 of
specific health and environmental effects research needs that
will assist EPA in implementing the elements of this strategy.
This list will also be used to assist in coordination with other
Federal agencies.
79. The following short-term activities are to be conducted
by ORD with assistance from CDC and the affected program offices:
A. Using best data at hand (carcinogenicity and repro-
ductive effects) ORD will continue to coordinate
hazard assessment techniques used by EPA in making
site-specific risk assessments.
B. ORD in conjunction with the CDWG will establish
exposure scenarios to estimate exposure under
various conditions likely to be encountered at
tiers 1 thru 6. A report is to be completed by
July 1984.
C. ORD will'develop a nomograph for converting from
2378-TCDD levels of contamination- in environmental
media to estimates of upper risk limits for a variety
of exposure scenarios; a final product will be
completed by July 1984. ORD will provide guidance
to the Regions and States on use of exposure
nomographs; this guidance will also be available
by July 1984.
80. The respective offices will review the three dioxin
hazard assessment documents being prepared by ORD and determine
the implications these documents have on the elements of this
strategy. This review is to be completed by January 1, 1984. In
addition, OW and OPTS will work with the FDA and the U.S. Fish
and Wildlife Service in assessing the relationship between the
FDA action levels for 2378-TCDD in fish and the proposed ambient
water quality criteria. Any conflicts between the two numbers
are to be identified and resolved, if possible, by March 1, 1984.
81. EPA's ORD will study the bioavailability and uptake
mechanism of sorbed 2378-TCDD. ORD will also investigate the
transport and transformation processes (bioaccumulation and bio-
magnification) of 2378-TCDD in fish, sediments, and plants for
use in food chain models and establishment of acceptable levels.
ORD will develop a time frame for these activities and identify
resource needs by February 1, 1984.
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82. The following research items are judged to be of suffi-
cient importance to the strategy that they should be specifically
identified in any inter-agency meetings that are conducted to
initiate health research:
A. Understanding the pharmacokinetic mechanism of
2378-TCDD induced toxicity to determine differences
between species in response to 2378-TCDD.
B. Understanding and developing the toxicological
and analytical relationship between 2378-TCDD
and "2378-TCDD equivalents" in complex mixtures
for more rapid and less expensive determinations
of 2378-TCDD levels and effects.
C. Conducting epidemiological studies at contaminated
sites to provide better information of risks for
regulatory decisions. This work will help establish
the cause/effect relationship of 2378-TCDD to
human disease.
Other Dioxins and Dioxin-like Compounds
83. A number of halogenated compounds related to dioxins are
thought to be almost as toxic as 2378-TCDD. They therefore have
the potential for causing significant exposure and risk problems.
Among these compounds, the halogenated dioxins and furans with
chlorine or bromine atoms at positions 2,3,7, and 8, and with at
least one hydrogen atom on the dioxin or furan structure, are of
special concern. These halogenated dioxins and dibenzofurans
are inadvertent by-products of a number of production processes
involving halogenated phenols, and are thought also to be created
in the course of combustion of a variety of halogenated aromatics.
The production and use of pentachlorophenol, and of other halo-
phenols and of their derivates, and of polybrominated biphenyls
and biphenylethers, are also of concern. In addition, combustion
of these compounds could, under certain conditions, create
"dioxin-like" compounds.
84. As part of this strategy's approach to dioxin the Dioxin
Management Task Force, in conjunction with the Chlorinated Dioxin
Work Group will develop by January 15, 1984, a work plan to study
the other dioxin isomers and "dioxin-like" compounds. The acti-
vities to be included in the work plan are: 1) determining the
specific sources of other dioxin isomers and dioxin-like compounds,
2) assessing their toxicity, 3) evaluating their environmental
fate and transport properties, 4) developing exposure and risk
assessments based on the above information, and 5) recommending
appropriate control actions. Implementation of the work plan
will be dependent on resource availability.
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85. Existing information, and chemical structure analysis,
will be used to investigate the sources of these compounds.
First priority will be given to investigating the contribution
from combustion and chemical manufacturing sources. Following
source identification, a sampling plan will be developed to
evaluate these suspected sources. The sampling plan will identify
the processes which are also sources of 2378-TCDD; thus, much
dual sampling will be avoided.
86. In order to take advantage of the sampling effort being
conducted for 2378-TCDD, the Regions will collect sufficient
sample volumes to analyze for both 2378-TCDD and the "dioxin-
like" compounds at those sites sampled in tiers 1 through 7.
87. As part of the development of an inter-agency program,
EPA's ORD will coordinate with the other Federal agencies in
developing a research program by April 1984 which addresses the
toxicology of the other dioxin isomers and the "dioxin-like"
chemicals. Additional toxicity data are needed, especially for
possible carcinogenic, reproductive, and teratogenic effects, and
bioavailability of the halogenated dioxins and dibenzofurans.
88. During FY 84, ORD will work with CDC, the U.S. Fish and
Wildlife Service, and other Federal agencies to develop analytical
protocols to measure "dioxin-like" chemicals in biological tissues,
waste emissions, and environmental media. Interim protocols will
be completed by September 1984.
89. ORD will explore the development and validation of bio-
analytical techniques for estimating the toxicity of complex
mixtures containing 2378-TCDD and "dioxin-like" compounds. It
is expected that such methods will reduce the need for the expensive
and resource-intensive isomer-specific analysis of the mixtures
associated with combustion and chemical processes.
90. ORD, in conjunction with the Chlorinated Dioxin Work
Group, will develop and apply methods to predict the fate,
persistence, and bioaccumulation potential of dioxins in the
environment. These efforts will begin in FY 84 in conjunction
with the development of the sampling program discussed above.
The results of these analyses will be combined with the source
asessments and toxicity studies to provide interim exposure and
risk assessments for the other dioxin isomers. Interim assessments
will be available by September 1986.
91. As sources of other dioxins and "dioxin-like" compounds
are evaluated, OSWER will, if appropriate, develop regulations
under RCRA in order to ensure the proper disposal of wastes from
such sources. As a first priority OSWER will promulgate the
regulations proposed on April 4, 1983, for the regulation of
process wastes containing tetra-, penta-, or hexachlorinated
dioxins and dibenzofurans, as appropriate.
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Coordination
92. Coordination between the various agencies is a crucial
element necessary to answer questions that have been raised
about dioxin exposure, environmental effects, and risk. In the
area of health research (toxicological studies and epidemiological
studies), the federal health and safety agencies under HHS
(e.g., CDC, NIOSH, and FDA), VA, and EPA should work closely
together. The governments of Canada and Italy, in particular,
should also be involved in the coordination of efforts pursuant
to this strategy. OSWER will have overall responsibility for
coordination.
93. To help achieve effective inter-agency coordination,
OSWER will develop a plan which will frame the issues to be
addressed by the agencies and, in relationship to EPA's strategy,
investigate various mechanisms (e.g., the Department of Health
and Human Services' committee to coordinate environmentally related
programs) to -secure interagency coordination. This plan will be
available by March 1, 1984, for review by the Deputy Administrator.
94. EPA recognizes the importance of the States'in effectively
implementing this strategy. Accordingly, the Regions are to coor-
dinate with the States in gathering information on specific sites,
in developing sampling plans and collecting samples, and in
devising the appropriate response. It is especially -important
to encourage States' initiative in any response efforts that may
take place at a contaminated site, including direction of respon-
sible private party .action. Such coordination will minimize
duplication and maximize resource availability.
95. It is very likely that the results of EPA's dioxin
strategy will point out the need for more work in a number of
areas, especially in the area of source characterization and
control technologies for the other dioxin isomers. Since funds
are not yet available for additional work, requests for additional
funding should be developed through the appropriate EPA and other
agency budget processes.
Community Relations
96. EPA recognizes the importance of dealing with the public
on such a sensitive issue as dioxin. Indeed, even the sampling
at uncontaminated sites (tier 7) will likely generate local
apprehension and questions. To communicate effectively with the
public, each Region should appoint one individual to handle
community relations relative to this dioxin strategy.
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97. The Regional community relations official will provide
updates, as needed, to local and State governments following the
community relations plan that is to be developed pursuant to the
OSWER interim guidance for tiers 1 and 2.
98. The AA for OSWER or his designate in conjunction with
EPA's press office will be the focal point at headquarters for
public relations.
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PART 3
INTERIM GUIDANCE FOR TIERS 1 AND 2
EXECUTIVE SUMMARY
Introduction
The Agency has been developing an overall strategy for
responding to the -public health risks associated with dioxin
contamination. The major components are:
1) A national study of selected sites to estimate the extent
of dioxin contamination (the "study" component);
2) Identification and coordination of research and regulatory
initiatives to prevent contamination (the "regulatory"
component); and
3) Development of appropriate response measures at contami-
nated sites (the "cleanup" component).
The EPA dioxin strategy provides for intensive focus on the most
toxic of the 75 dioxin isomers — 2,3,7,8-tetrachlorodibenzo-p-
dioxin (2378-TCDD). The other di'oxin isomers, which have different
physical and chemical properties, will be evaluated as part of
the strategy to determine whether they merit the same intensive
investigation.
This section provides interim guidance on the third major
component listed above: the identification of TCDD contaminated
sites and the development of appropriate response measures.
For the overall strategy, the Agency has identified a seven
tier hierarchy of sites based on an estimated decreasing potential
for 2378-TCDD contamination. The focus of the cleanup component
will be initially on the most serious sites, and this guidance
sets up a controlled, structured approach for working down through
tiers 1 and 2 to identify 2378-TCDD contaminated sites. The
national study will utilize the data being collected in the
cleanup component, but will focus its resources on tiers 3 through
7. Of course, any site discovered to be contaminated with 2378-
TCDD in the national study or otherwise will be referred for
appropriate cleanup response.
For the cleanup component, the 2 tiers of concern are:
Tier 1 - Current, if any, and former sites of 2,4,5-TCP
production.
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Tier 1A - Transport, treatment, storage, and disposal (TTSD)
handlers or sites used by tier 1 facilities.
Tier 2 - Sites, where 2,4,5-TCP was or is used as a precursor
to produce another chemical product (e.g., hexachlorophene,
2,4,5-T, silvex, etc.)
Tier 2A - Transport, treatment, storage, and disposal (TTSD)
handlers or sites used by tier 2 facilities.
Due to the manufacturing processes involved, it is estimated
that 80-95% of the 2378-TCDD produced in this country is associ-
ated with tiers 1 and 1A. While it is believed that there
are approximately 20 facilities in tier 1 and 30 in tier 2,
there is no accurate count of handlers or sites in tiers 1A or
2A. Accordingly, a primary objective of this guidance is to set
forth a process for defining the dimensions of the universe to
be investigated.
A second objective of -this guidance is to see that the Agency's
limited sampling resources are initially focused on the most
serious sites. Regions are directed to place primary emphasis
on tier 1 sites, and later on the other tiers (tier 2) consistent
with the Regions' work plan and with the approval of the AA for
OSWER.
Additionally, it is recognized that some Regions are already
sampling at sites in tier 2. The demand that this sampling has
placed on the national lab capacity and Superfund support contracts
is considerable. In order to focus on the potentially more serious
sites in tier 1A, and to maintain resources for other Sxiperfund
work, the Agency has made a decision that new sampling at tier 2
sites should be delayed, where it is not inconsistent with prior
commitments, until the size of the universe for both tiers is
better defined. Then, the Agency will make decisions regarding
the best way to apportion laboratory capacity, support' contracts
and technical resources. This interim guidance sets forth certain
other decisions which will have to be coordinated with OSWER in
order to maintain a coherent Agency approach and to control the
resource demands nationally.
Approach
The Regions' activities at the sites will involve several
phases. The basic approach, explained in more detail later in
this interim guidance, is as follows:
Information Collection
1. Consolidate Regional and Headquarters data bases to
identify tier 1 and 2 sites.
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Collect information for
begin identification of
sites.
known tier
tier 1A and
1 and 2 sites to
2A facilities and
Depending
interviews,
the field.
on the results, arrange site visits, employee
and other evidence collection necessary in
Field Investigation
1. Sampling at tier 1 sites
mation collection phase.
should begin during the infor-
2. No new sampling should be initiated at tier 2 sites
until the results of the information collection process
are analyzed, and the Agency determines how it will
proceed. The same is true for transportation, treatment,
storage and disposal handlers or sites associated with
any of the 2 tiers.
Response Acti-vities
1. If 2378-TCDD contamination requiring a cleanup response
is identified, direct initial efforts at getting poten-
tially responsible parties (PRPs) to take appropriate
action (e.g., remedial investigation, emergency response).
2. If necessary, develop a Superfund cleanup response.
Detailed Guidance
Whenever possible, the Agency will work closely with the States
and encourage them to be the lead agency as it does throughout
the Superfund program. After the Agency has conducted an initial
screening of the sites, it will look to potentially responsible
parties (PRPs) to undertake Remedial Investigations (RI). Due
to resource demands placed on the Agency, the Agency^has made a
management exception to current policy by allowing PRPs to under-
take Remedial Investigations. The scope of any remedial investi-
gation conducted by a PRP will be incorporated into an adminis-
trative order.
Community Relations Plans.
Community Relations Plans (CRPs) must be developed for each
site in accordance with the guidance issued to the Regions on
May 9, 1983 with modification as necessary for consistency with
this interim guidance.
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Information Collection
The Office of Waste Programs Enforcement (OWPE) is in the
process of identifying current and former 2,4,5-TCP manufacturing
sites (tier 1) and current and former manufacturers who purchased
2,4,5-TCP as a feedstock in pesticide production (tier 2). The
compliance monitoring staff of the Office of Pesticides and Toxic
Substances Enforcement (OPTSE) will assist OWPE in identifying
potential 2378-TCDD dioxin sites by providing accesss to their
FATES computer system from which information on pesticide pro-
duction can be obtained. Further, OPTSE in conjunction with the
Regions (Air and Hazardous Materials Division) will summarize and
provide information from the Toxic Substances Control Act (TSCA)
Section 6 dioxin inspections. Various program and enforcement
offices in Headquarters are being asked to compile information
and coordinate it through OWPE. The results of the survey will
be made available to the Regions.
•
The Regional Superfund program and enforcement offices should
confer with the Regional Pesticides, Toxic Substances and the
Resource Conservation and Recovery Act (RCRA) program and enforce-
ment offices to obtain information on production, transport,
treatment, storage, and disposal of 2,4,5-TCP wastes from facil-
ities identified by OWPE and other facilities the Regions may
identify. The Regions should notify OWPE of the results of
their document search by September 6, 1983. This information
will be used by OWPE to complete its categorization of sites and
facilities into the appropriate tiers. OWPE will provide this
"revised categorization" to the respective Regions by September
19, 1983, and will update this information as necessary.
In order to gain more informaton on potentially contaminated
2378-TCDD sites the Regions will issue CERCLA S104/RCRA §3007
information request letters by September 30 to all tier 1 and
tier 2 facilities identified by OWPE and the Regions. Recipients
of the letter will be given 30 days to respond. The letters
will request information on the amounts of waste generated and
disposed, current and past disposal practices, including disposal
site locations and waste haulers, and other pertinent information
that may be needed to support an enforcement or Fund-financed
response action. Use of enforcement actions under RCRA §3008 for
inadequate responses to the information request letters should be
initiated when appropriate.
The Regions are advised to remain firm on the 30-day deadline
for responses to the information request letters. Extensions, if
granted, should only be granted for good cause shown and should
not exceed two weeks.
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Most responses, even with a two week extension, should be in
the Regional offices by November 15, 1983. The Regions should
review the responses and provide to OWPE, by December 15, 1983,
the following:
1) List of facilities that complied with the request;
2) List of facilities that failed to respond;
3) List of additional sites", including transporters,
treatment, storage, and disposal facilities identified
in the responses; and
•
4) A Regional plan for further investigative and response
activities for each site.
After compilation and review of all available information,
the Region will determine if additional information gathering
through follow-up site inspections, interviews with current and
former site employees, responsible party searches, and/or title
searches is needed. The Regions should also consider the use
of a trained investigator to compile information and assist in
investigations.
.Preliminary Investigation Phase (.Screening)
This portion of the guidance explains how to conduct a syste-
matic investigation of facilities. Tier 1 sites will be screened
first in order to focus efforts on sites posing (potentially) the
most urgent and widespread public health concerns. By December
5, 1983, the Regions -should implement and provide to OWPE a
screening program for confirmed tier 1 sites. When OSWER deter-
mines that the resources are available nationally, tier 1A, 2,
and 2A sites will be investigated following these same procedures.
During the preliminary investigation phase an initial screening
of tier 1 facilities shall be' conducted to determine if 2378-TCDD
is present at the site. If it is present, further remedial inves-
tigation or endangerment assessments shall be conducted as des-
cribed in the response phase of this guidance. Initial screening
of tier 1 facilities will be conducted by EPA or States concurrent
with information gathering.
Once the Region has identified the tier 1 facilities targeted
for preliminary investigation, it will devise a screening program
for collection of a limited number of environmental media samples
at these sites. In Regions where several tier 1 facilities are
to be screened, an inspection scheme should be developed to help
management set priorities and schedule investigations.
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In general, where currently operating facilities have been
targeted for sampling, the Region should look to FIFRA, TSCA,
RCRA, and/or CERCLA for authorities to conduct record inspections
and/or collect environmental media samples. In addition, the
Regions should address compliance with all applicable rules and
regulations.
Field Investigation Procedures
The following procedures for screening sites for potential
2378-TCDD contamination should be instituted for tier 1 sites.
1) Develop and implement an initial site sampling plan
(screening program using the protocols and procedures
developed by EPA/ORD and the Centers for Disease Control
(CDC) to sample the most probable locations of dioxin
contamination at the site or in the immediate vicinity) .
Site inspection schemes should be reviewed with OWPE
Regional Coordinators - Compliance Branch. During this
round of sampling, limit the number of samples taken to
only those which are necessary to determine if dioxin is
present. States should be advised by Regions of the
site inspection schemes. For active industrial sites,
CDC should be contacted to coordinate with the National
Institute for Occupational Safety and Health (NIOSH) for
further sampling guidance. If there are people living
in the area, the State health officials and CDC should
review all sampling protocols from the beginning. CDC
should be contacted through its staff person in each EPA
Regional Office.
2) Initial field --investigations must employ EPA chain of
custody procedures, document control, site safety plan
procedures and Quality Assurance/Quality Control
procedures.*
3) Analysis for 2378-TC.DD in soil will be conducted using
state-of-the-art low resolution GC mass spectrometry
methodology and appropriate detection limits. Analysis
for 2378-TCDD will be performed using high resolution
GC mass spectrometry methodology in enviormental media
other than soil. Qualitative analytical screening for
other dioxin isomers should also be considered by the
Regions at sites where there is reason to believe that
other dioxin isomers may be present. The Regions should
contact the National Contract Lab Program in order to
schedule sample analysis as early as possible. These
samples should be labelled as tier 1 - 2378-TCDD
* Guidance for QA/QC is available from the Office of Research and
Development.
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samples in addition to any of the identifiers used.
..(Coordination should be through the Regional Environmental
Services Division (ESD) Directors).
4) If the initial sampling results indicate 2378-TCDD is
present, and response action is to be pursued through
either enforcement or Fund-financed activities, the proce-
dures set forth in the Response Phase of this guidance
should be followed as appropriate. All phases of response
must be in accordance with the National Contingency Plan.
The priority for taking either enforcement or response
actions at dioxin sites will be determined by evaluating
the seriousnes of the problem at that site relative to
the problem at all other sites whether they include dioxin
or not.
Regional Workplan
The information obtained from the field investigations should
be used by each Region to develop a Regional workplan for tier 1
sites which initially determines whether or not a contaminated site
will be addressed through Fund-financed activities or enforcement
authorities, and projects a schedule for further action. Workplans
should be submitted to OSWER by March 15, 1984. These workplans
will be reviewed by OSWER in light of the national demand for
resources and analytic 'laboratory capacity. OSWER will consult
with the Regional Offices on any adjustments to the workplans
based on the dimensions of the national situation.
Response Phase
Response actions, which are consistent with the Region's work-
plan and the approval of the AA for OSWER, will be initiated at
a site when the analytical results of the preliminary field
investigation (screening) confirm the presence of 2378-TCDD and
the Region_determines that the situation warrants response. In
evaluating'whether .or not to take a response action at a site,
the Agency will consider criteria such as the following: the
location of the site, the site's use, the demography, etc.
If technical assistance or expenditure of funds from other
Federal agencies is needed, a Regional Response Team (RRT) meeting
should be convened. The RRT will serve as the coordinating
mechanism within the Federal government and for Federal/State
cooperation. In addition, because the RRT serves as the coordi-
nator for inter-agency actions, it can also become the focal
point for communications with the local citizens and the press
at a site.
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Enforcement Procedures (See Figure 2)
To support possible enforcement response actions at tier 1
sites where 2378-TCDD contamination has been confirmed through
initial screening, additional information gathering may be needed
to supplement the material gleaned from the CERCLA 104 and RCRA
3007 information request letters and from FIFRA/TSCA inspections.
In the Regions, the Air and Hazardous Materials Division will
determine the sufficiency of information collected and have
primary responsibility for compiling information from' local,
State, and Regional sources. At the Region's request, OWPE will
compile information from computer systems such as FINDS in the
Management Information Data Systems Division and from the various
program and enforcement offices to support an enforcement response
action at a particular site.
Once the potentially responsible parties (PRPs) have been
identified, notice letters will be issued apprising PRPs that
EPA has conducted or will conduct planning or response actions
at the .site to determine both the nature and extent of the dioxin
contamination. the PRP will be offered the opportunity to
undertake the necessary assessment and response actions at the
site, and will be apprised of possible liability under CERCLA
for injunctive relief or cost recovery in the event Superfund
action is taken. If the PRPs choose to undertake the necessary
response actions at the site, the Region should, depending upon
the evidence available, issue an administrative order on consent
in order to gather additional data and direct the appropriate
response measures (e.g., CERCLA §106, RCRA §3013, RCRA §7003).
Where PRPs decline to undertake the necessary remedial investi-
gation activities the Region will pursue, aftfer consultation
with the Office of Waste Programs Enforcement (OWPE) and the
Office of Enforcement Counsel Waste (OEC-Waste), one of the
following options:
•
1) Issuance of a unilateral RCRA §3013 or CERCLA §106 order
to obtain the information necessary to conduct a
feasibility study;
2) Initiation of a Fund-financed removal action;
3) Initiation -of a Fund-financed remedial investigation/
feasibility study (RI/FS); or
4) Initiation of an enforcement-funded endangerment/
alternatives assessment.
The option selected will be dependent upon such variables as
the complexity of the case, severity and imminence of hazard, the
number of sites needing response action, availability of Super-
fund and/or enforcement dollars, and availability of personnel.
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If Option 1 above is selected and the PRP complies with the
order, then EPA will perform the feasibility study. If the PRP
chooses not to comply with the order, then the Region should
pursue Option 2, or 3, or 4. If option 2 is chosen, the proce-
dures outlined for "removals" in the Response Section below
should be followed. For option 4, an endangerment assessment
must be performed by the Region. In addition, an endangerment
assessment may also be necessary for options 2 and 3 if a cost
recovery action is to be taken. This assessment will .examine
the nature and quantity of the dioxin or any hazardous materials,
exposure pathways, human and animal populations exposed or poten-
tially exposed and the actual or potential risks and effects
associated with the exposures to the hazardous materials. At
this point, CDC should be notified of the information contained
in the endangerment assessment and be asked for a health assess-
ment or advisory. CDC will coordinate with NIOSH for active
work-related situations. The endangerment assessment along witn
the subsequent alternatives assessment are considered to be 'the
critical components of the enforcement strategy, and are nece'ssary
to ensure successful prosecution of an enforcement action under
administrative or judicial statutory authorities.
Upon completion of the Fund-financed RI/FS or the enforcement
financed assessments, the Region will have 60-120 days to nego-
tiate an agreement with the PRPs for response action.
If an agreement, can be reached, it will be embodied in an
administrative order or a consent decree pursuant to §106 and/or
§7003. If an agreement cannot be reached, the Region will pursue,
after consultation with OWPE and OEC-Waste, one of the following
options:
*
1) issuance of a unilateral administrative order pursuant
to §106 and/or §7003; or
2) Initiation of a judicial action pursuant to §106 and/or
§7003; or
3) Initiation of a Fund-financed response action followed
by a §107 cost recovery action.
If Option 3 is selected, then the Region will initiate a
cost recovery action pursuant to §107 for reimbursement of
expenditures under Superfund for site planning and response and
other expenditures. Cost recovery actions will be conducted in
accordance with existing procedures and policies.
Dioxin sites identified for action by States may require
Agency overview in the form of technical support for enforcement
actions or response actions. In certain cases, actions may
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involve joint federal EPA and State efforts. Depending on the
success of State enforcement action, direct EPA involvement may
be necessary.
Fund-Financed Response .
If the initial sampling (i.e., the limited sampling performed
as step #1 of the Field Investigation Phase) results indicate
that dioxin is present, and the response is to be Fund-financed,
then the Agency must decide if the situation warrants a removal
action. Regions must recommend removal actions, with required
documentation to the Assistant Administrator for OSWER. CDC
should be consulted in case a health assessment or advisory is
needed. If EPA believes temporary relocation is warranted, it
must ask the Federal Emergency Management Agency (FEMA) to make
such a determination.
It is possible that either or both short-term and long-term
cleanup activities may be necessary at a site. (If the site is
going to need long-term or "remedial" work, then the site
needs to be scored .in accordance with the Hazard Ranking System
for ranking and placed on the National Priorities List (NPL), if
appropriate.)
Additional investigation, planning and design work for long-
term activities can be performed while short-term cleanup
activities are being performed. If work other than removal
action Is needed, the following activities should take place:
1) A more detailed sampling effort should be conducted at
the site, setting up the sampling locations in a grid
network extending beyond the facility boundaries.
Environmental media other than soil should also be
sampled when appropriate. Once again, CDC and/or NIOSH
should be involved in this process. Sample protocols
and analysis schedules should be reviewed with OERR.
As noted above, the Region should contact the Sample
Management Office of the National Contract Lab Program
in order to schedule all sample analyses and mark
samples "Tier 1-TCDD". Coordination should be through
the Regional ESD Directors.
2) Once the results from this second sampling are obtained,
> EPA should again request a health advisory or assessment
from CDC. Based on CDC's recommendations, EPA must
decide if temporary or permanent relocation should be
considered for persons residing in the vicinity. As
noted above, FEMA makes the determination for temporary
relocation during removal activities. If temporary
relocation is contemplated during remedial actions, EPA
makes the determination (under a recent redelegation of
authority from FEMA) that it is necessary and FEMA
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implements the determination. EPA also has the responsi-
bility for making the determination concerning permanent
relocation, and FEMA implements it.
3) If further response activities are warranted, and the
site has been proposed for inclusion on the NPL, feasi-
bility study and design-work should be initiated, followed
by additional construction.
Separate guidance is attached concerning the short-term and
long-term technical options for destruction and disposal of
dioxin which are currently available or being developed. In
addition, information is included regarding the notification
procedures to be followed for the transport or disposal of
dioxin.
Technical Assistance
The Region should consider using their FIT and TAT as well as
FIFRA, TSCA, and Water inspection program resources in the infor-
mation collection and initial screening phases. The Superfund
contractors' (REM/FIT and TAT) as well as the technical enforcement
support (TES) contract should be used to support field investi-
gations, data analysis and development of feasibility studies
for 2378-TCDD contaminated sites. Water quality program monitoring
resources may also be useful in the investigative mode for fish
and water sampling. Environmental media samples taken during
the field investigations can be analyzed by the Superfund contract
laboratory program. if the capacity of these laboratories is
exceeded, other laboratories available to the Region through
contractual arrangements, ORD or the Environmental Services
Division, may be employed after consultation with OERR's Technical
Support Division.
Financial Assistance
The States can use the money allotted to them through the
CERCLA/RCRA 3012 program to investigate sites thought to be
contaminated with 2378-TCDD. For example, if the State has
targeted 100 site inspections in their application, and now
wishes to inspect 20 2378-TCDD sites. The States can perform
activities at the 20 2378-TCDD sites as part of their established
goal. This would simply reestablish priorities for the States.
The following activities can be funded with these grants:
preliminary assessments, site inspections, responsible party
searches, discovery, and site inspection followup. For more
information about this source of funds, you can refer to the
Federal Register Notice of February 7, 1983 and the EPA guidance
issued on March 8, 1983.
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FldUMe I
Review of local,.state
and federal files by
HQ, Region, and State
OWPE List Of 2,4,5-TCP
Manufacturers and 2,4,5-TCP
Pesticide Derivative
Manufacturers
wMMoml (MM
104/3007 Letters to
OUPE List of Facilities
TIER 1
Manufacturers of
TIER la
TTSD facilities of
TIER l
TIER 2
Sites where 2,4,5-TCP
was used as a precursor
to produce another.
chemical product
TIER 2t
TTSD facilities of
TIER 2
FIFRA* Inspection
or
TSCA Inspect ion/Sanplinj
or
Superfund Screening
Superfund Screening
Consult with OSHER
prior to taking
further action
FIFRA Inspection
or
TSCA Inspection/Sampling
or
Superfund Screening
Superfund Screening
, 2,3,7.8-TCDD
present
Response Action (see Fig. 2)
and
Additional information
gathering for enforcement
purposes, e.g., files search,
interviews, responsible party
search
, No 2,3,7.8-TCDD
Present
|Ho Response Action]
Consult with OSHER
prior to taking
further action
-------
FIGURE 2
S3013 A.O. for RI
EPA does FS
CO NOTICE LETTER
. FOR RI/FS/RD/RA
S3013/106 A.O. for
RI/FS/RD/RA
or
S106 and/or S7003
Consent Decree for
RI/FS/RD/RA
$3013 Unilateral A.O..
for RI
or
4
-Fund-Financed RI/FS
and/or Removal
or
Enforcement-Financed
-Endangerment/Alternatives
Assessment
r.r.. . r.^
EPA does FS
F106 and/or S7003 A.O.
or Consent Decree
unoooparaOv*
negotiate RO/RA
irauocaeakl
60-120 day*
^§106 and/or S7003 Unilateral
.O. for RD/RA
or
5106/7003 Civil Action LITIGATION
or
Fund-financed RD/RA
-------
ATTACHMENT I
DISPOSAL GUIDANCE
Background
Although a significant amount of dioxin-related research work
has been published, most is related to the toxicity or destruction
of dioxin in a solubilized form. This is rarely applicable to the
conditions existing at most Superfund sites. These sites are
often characterized by a variety of contaminated soils, gravels,
and other materials, for which there is little available infor-
mation to use in developing a technically sound prediction of
dioxin1s behavior in the environment, its containment efficiency,
or treatment effectiveness.
Due to dioxin1s known toxicity and hazards to personnel, the
scientific community has been reluctant to conduct controlled
investigations of dioxin1s environmental behavior outside of the
laboratory. These risks, plus the high cost of analytical testing,
have also limited rigorous studies of uncontrolled dioxin releases
to a few instances. Furthermore, only at Seveso, Italy, and Snytex
have significant investigations been conducted into treatment
alternatives for dioxin-contaminated soil. At these and the
other sites, the contaminated soil was eventually contained in a
•landfill or is .presently in an interim storage facility, awaiting
the development of technologies related to dioxin-contaminated
soil.
Remedial Action Alternatives Considered
Over 40 possible treatment processes and over 500 sources of
information were considered in the initial screening of alterna-
^ •! *» |*k O f f\ V* V V"\ J-*l £ S^ ^ f+ 4 \~\ •! 1 ^ 4- • T r* t » 1 S^ * r U •! *^ \f XX V / C* +• f*l lit A 4 S^. ^f ^ f\ ft I ^ /-V T F^
Missouri.
iiiLuirindi. ion wete cuns luerreu in cue iniciaj. screening on aicei
tives for the feasibility study Minker/Stout dioxin site in
M-i e o/-\i i v* i
The treatment processes were screened on the basis of 1)
state of development, 2) health and safety risks, 3) process
complexity and constructability, 4) reliability, and 5) cost.
Six remedial alternatives were selected for a detailed eval-
uation. Alternatives A through C rely on the principle of
containment to reduce dioxin exposure which, due to the demon-
strated insoluble nature of dioxin in these soils, centers around
immobilizing the contaminated soil particles. Alternatives D
through F rely on the principle of treatment to reduce dioxin
level, in addition to containment of the treatment residue. In
reality, each treatment alternative is a two-stage process,
involving soil extraction (thermal or solvent), followed by a
destruction process. Contaminated soil has several unique
characteristics that make the application of any of the treatment
alternatives a challenge. Among the special requirements are:
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0 The need to process a wide range of contaminated materials,
e.g., rocks, clay, roots, and other materials on-site.
0 The requirement that the remedial alternative be capable of
processing all contaminated material. Combination of reme-
dial alternatives for various types and concentrations of
contaminated material were not considered.
0 The use of Level C or higher personnel protection for all
soil handling and treatment activities.
0 The potential listing of 2378-TCDD as a RCRA waste, which will
significantly impact storage, transportation, monitoring,
and treatment requirements. If residue tests and other
limitations do not enable a delisting of the treated residue,
there would appear to be little cost incentive to treat the
soil prior to containment in a fully permitted secure
landfill.
The following six remedial alternatives were selected for
a detailed evaluation at the Minker/Stout site. Alternatives D,
E, F and the possible fixation portion of Alternatives A and C
have significant technical unknowns that warrant pilot testing to
better demonstrate their application to dioxin-contaminated soils.
Alternative B and the remainder of Alternatives A and C are
highly site-specific and do not .warrant pilot testing but may
need additional site testing.
Alternative A — Secure Soil In Place
This alternative would secure the soil in place and prevent
public site access. This would likely involve insitu soil fixation
and securing the site with a subsurface perimeter grout curtain,
an impermeable cap over the contaminated area, and diversion of
surface runoff. Permanent resident relocation and house demolition
would be necessary within the sites and for any additional house-
holds inside an undertermined buffer zone. A longterm site
monitoring and maintenance program would be necessary to monitoring
the ground water and conditions in the surrounding environment.
Alternative B — Consolidate Soil On-Site
This alternative would remove the contaminated soil and consoli-
date it into one area at the site. Due to the varying soil
depths, unknown site hydrogeology, and the need for a positive
liner and leachate collection system, a double-lined, above-grade
concrete vault would be used to contain the contaminated soil.
Permanent resident relocation and house demolition would be
necessary within the sites and for additional households inside
a buffer zone. A long-term site monitoring and maintenance
program would also be required.
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Alternative C — Secure Soil Off-Site
This alternative would remove and transport the contaminated
soil to a secure hazardous waste landfill for disposal. In
accordance with the April 4, 1983, Federal Register, the Agency
is currently proposing the addition of dioxin wastes to the RCRA
regulations. If this proposed rule is promulgated, the design
and operation of each landfill disposal facility would need to be
thoroughly evaluated before dioxin could be added to the landfill's
permit. The removed soil volume and up to a foot of additional
fill would be added to restore the site drainage and to cover any
fugitive traces of contaminated soil. The site would be reland-
scaped and the houses rehabilitated to completely restore the
area.
Alternative D — Incineration
This alternative would involve the direct thermal extraction
and destruction of the 2378-TCDD-contaminated soil. The contami-
nated soil would be stabilized on-site or removed to a concrete
vault, or other storage facility, where it would remain while
the incineration process was pilot tested and developed for
this particular contaminated soil. The low levels of soil con-
tamination, required high destruction and removal efficiency,
and widely varying soil characteristics will likely expand the
'state-of-the-art of incinerator technology.
A significant permitting effort could be necessary for the
pilot tests and for the siting of a full-scale facility. Fol-
lowing the permitting process and the construction of the facil-
ity, the soil would be transported to a size reduction and
handling process, and then to an incinerator. The incinerator
particulate and soil residue would be transported to a secure
landfill site, unless extensive testing allowed the residue to
be delisted under RCRA.
Alternative E — Solvent Extraction
This alternative would extract the dioxin from the soil with
a solvent, concentrate the solvent, and then destroy the dioxin
in the solvent. The contaminated soil would be stabilized on-
site or removed to a concrete vault where it would remain while
the solvent extraction process as pilot tested and developed.
A significant permitting effort could also be necessary for
the pilot bests and the siting of a full-scale facility. Following
the permitting process and the construction of this process, the
soil would be transported to a size reduction and handling process,
and then to the solvent extraction process. The resulting contami-
nated solvent would be concentrated, with the concentrate under-
- 41 -
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going degradation and incineration. The incinerator particulate
and the soil residue would be sent to a secure landfill site,
unless extensive testing allowed the residue to be delisted.
Alternative F — Storage While Awaiting Development of
Emerging Technology
This alternative would allow for the development of emerging
technologies other than incineration and solvent extraction. The
contaminated soil would be removed and stored until such time* as
emerging technologies (such as supercritical water reactors, wet-
air oxidation, fluidwall reactors, and biological degradation)
could be pilot tested and evaluated for their ability to be
competitive with existing technology. Today, these technologies
are not developed sufficiently to be used commercially for this
type of hazardous waste. All of these technologies have several
major technical hurdles to overcome before they can be considered
viable. There is a risk that these emerging technologies may
never become cost effective for these soils and, therefore, a
contingency .plan would be necessary, should a research and devel-
opment program not proceed as quickly as planned or be unable
to demonstrate an acceptable alternate technology.
Long and Short-Term Control Strategy
Preliminary testing .indicates that three Minker/Stout soil
samples subject- to EP toxicity tests all showed leachate containing
no 2378-TCDD above the 1-ppt 'detection limit. In its current soil
matrix, 2378-TCDD appears to be water insoluble, as well as non-
volatile and, therefore, soil particle movement is necessary to
spread the contamination.
<
Containment technologies are based on the dioxin-soil binding
characteristic and focus upon the restriction of soil particle
movement. These technologies can be used as a short-term interim
solution when coupled with treatment technologies for future
processing, or as a long-term remedy.
When dioxin contamination above 1 ppb is detected, a short-
term control strategy should be immediately developed. This
short-term strategy should focus on containing the contaminated
soil and preventing airborne migration and surface stormwater
erosion. Public access•to the site should be limited. Resident
relocation will be based on health advisories or assessments
issued by the Centers for Disease Control and determinations by
the Federal Emergency Management Agency or EPA that relocation is
necessary to protect public health in accordance with a recent
redelegation of authority from FEMA. A monitoring program should
be designed to determine the extent of surface and subsurface
migration. If the site cannot be controlled on a short-term
basis, then excavation and temporary storage will be required.
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EPA has proposed the listing of a number of dioxins (including
2378-TCDD) as hazardous wastes under the RCRA regulations. Cur-
rently, however, the disposal of 2378-TCDD contaminated wastes
(including soils) is covered by TSCA (40 CFR 775.197). These
regulations have governed the manner in which temporary storage
has been provided at several sites including:
Denny Farm, Missouri
Syntex Verona, Missouri
Vertac Jacksonville, Arkansas
Saugett, Illinois
Love Canal/Hyde Park, New York
Temporary storage may be undertaken by the responsible party,
or as a Fund-financed immediate removal or as a remedial action.
As sites are discovered and actions planned, the TSCA mechanism
can be utilized for technical review of any actions which might
be taken. For further information contact Dr. Donald Barnes,
Chairman, Chlorinated Dioxin Work Group at 382-2897.
Contaminated sites will require extensive sampling to deter-
mine the extent and severity of the problem and to assess the
performance of short-term controls.
The destruction of dioxin in soil will require the development
and pilot testing of technologies and should be considered as a
long-term (greater than two years) control strategy.
To destroy 2378-TCDD, treatment technologies must first vaporize
or solubilize the 2378-TCDD from soil thus breaking the dioxin soil
bond. In doing so, partially treated residues, or contaminated
materials released during processing, have the potential to spread
contamination via any one of the exposure routes (water, air, and
soil) with highly mobile soluble, volatile, or particulate forms
of 2378-TCDD. While treatment technologies may be considered the
ultimate solution, they could entail significant health risks
during processing.
State-of-the-art methods will be necessary to mitigate the
exposure hazard -to workers, the public, and plants and wildlife.
The control of dust, treatment emissions, water contact with soil
or treatment residue, must be an integral consideration when
evaluating destruction technologies and will have to be considered
as part of any future pilot testing program.
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