United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
December 1984
Air
National Dioxin
Study Tier 4 —
Combustion
Sources
1984 Status Report
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National Dioxin Study Tier 4
Combustion Sources
1984 Status Report
By
Air Management Technology Branch
U.S. ENVIRONMENTAL PROTECTION AGENCY
'Office Of Air And Radiation
Office Of Air Quality Planning And Standards
Research Triangle Park, NC 27711
December 1 984
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This report has been reviewed by The Office of Air Quality Planning And
Standards, U.S. Environmental Protection Agency, and has been approved
for publication. Mention of trade names or commercial products is not
intended to constitute endorsement or recommendation for use.
This report is a status report for an ongoing, evolving project. Project
plans discussed herein are thus subject to change as the program is
implemented.
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National Dioxin Strategy
— Tier 4
Report To The Dioxin Management Task Force
Air Management Technology Branch
Monitoring and Data Analysis Division
Office of Air Quality Planning and Standards
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
December 1984
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Introduction
The Environmental Protection Agency (EPA) is undertaking the National
Dioxin Strategy to identify more clearly the existence of chlorinated dioxin
compounds in the environment. The study is divided into seven tiers, Tier 4
being directed toward combustion sources. The results of this effort will be
summarized in a report to the U.S. Congress at the end of 1985. This paper
presents a summary of the plans and accomplishments under Tier 4 through
December 1984. It is intended primarily for internal communication within the
Agency but contains some background for others with interest in the study and
its progress.
The Office of Air and Radiation (OAR) has been delegated responsibility
for planning and management of Tier 4. The Office of Research and Develop-
ment (ORD) is responsible for sampling and analytical guidance and a major
portion of the stack sampling program. ORD is also providing analytical sup-
port via an arrangement with three EPA laboratories (Duluth, Bay St. Louis, and
Research Triangle Park), collectively known as the Troika. EPA's Regional
Offices are also responsible for implementing various aspects of the Tier 4
effort. A Tier 4 Work Group, comprised of representatives from throughout the
Agency, functions in an advisory role in the formulation of plans and the
review and interpretation of data.
Any comments or questions on the Tier 4 study should be sent to James H.
Southerland, Mail Drop 14, Air Management Technology Branch, Office of Air
Quality Planning and Standards, U.S. Environmental Protection Agency, Research
Triangle Park, North Carolina 27711.
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TIER 4 - COMBUSTION SOURCES
The National Dioxin Strategy directs Tier 4 to focus on "combustion
sources, such as incineration of hazardous and municipal waste (including
sewage sludge), wire reclamation facilities, internal combustion engines,
home heating units (i.e., wood burning stoves), industrial fossil fuel-fired
boilers, and inadvertent combustion sources." This broad directive covers
literally millions of individual sources. Since it would be economically and
otherwise impractical to test each source or even each source category, con-
siderable thought and judgment have gone into planning how best to answer the
foil owing questions:
1. Which, if any, general combustion source categories likely emit
2,3,7,8-tetrachlorodibenzo-p-dioxin (2378-TCDD) and other chlorinated isomers
of dioxins and furans?
2. At what concentrations are those compounds emitted to the environment?
3. Do the ambient air concentrations resulting from these emissions pose
an unreasonable risk to the public?
The results from Tier 4 will be summarized in a report to Congress,
scheduled for December 1985. The results will be useful in making a decision
to list dioxin under Section 112 of the Clean Air Act (for hazardous air pollu-
tants).
Basis For Investigation Of Combustion Sources
There are several unproven hypotheses concerning dioxin emissions from
combustion processes. Dow Chemical's "Chemistries Of Fire" theory! proposes
that dioxins are a natural byproduct of fire and will be formed at some
quantities in all combustion processes. However, experimental results by
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others^ suggest that dioxins may only be emitted only under limited conditions.
The most prevalent theories^ involve the incomplete combustion of polychlori-
nated dibenzo-p-dioxin (PCDDs) or PCDD precursors.
Since combustion sources are ubiquitous and are fairly concentrated in
urban areas, it is conceivable that a large portion of the United States
population may be exposed to some level of dioxin, including 2378-TCDD, in the
ambient air. More data are needed to determine the magnitude and extent of
exposure to dioxins from combustion sources. Current evidence does not
suggest that an unreasonable risk exists. However, there are uncertainties,
and the Dioxin Strategy provides an opportunity to perform an orderly inves-
tigation of the potential of combustion sources to emit dioxin. An assessment
of risk from each source tested with inferences to the source category will
result from this effort and, if warranted, appropriate regulatory steps devel-
oped in follow-on programs to eliminate any unreasonable risks.
Project Approach
There are many data gaps in the available information concerning emissions
of dioxins from combustion sources, and a number of different approaches could
be taken to fill these data gaps. After considering various alternatives, the
Agency has decided to focus the Tier 4 effort on the collection of source data
from a number of combustion source categories which are reasonably believed to
have the highest potential to emit 2378-TCDD.* Thus, the primary objective of
the Tier 4 project is one of problem definition (i.e., what source categories
emit dioxin and at what concentration). Detailed stack, ash and other media
* However, source categories for which three or more tests have already been
completed (e.g., municipal incinerators) will not be tested under Tier 4.
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samples are being collected and analyzed for 2378-TCDD, 2,3,7,8-tetrachloro-
dibenzofuran (2378-TCDF), and the higher dioxin and furan homologues (i.e.,
tetra, penta, hexa, hepta, and octa).
Two levels of source sampling are being carried out in Tier 4. First,
relatively inexpensive ash samples (screening) are being collected from the
combustion source categories listed in Table 1. These source categories are
believed to have some likelihood of emitting dioxins and also include source
categories recommended by EPA Regional and State officials. Ash samples will
usually be collected from three different sources in each source category.
These samples will generally consist of fly ash from the control device hopper
or "bottom" ash where no control devices are present. These samples will be
analyzed for 2378-TCDD, 2378-TCDF and the higher dioxin and furan homologues.
Because of the nature of these samples, these data can only be used to provide
a qualitative indication of the likely presence of dioxins in the flue gas
emissions. They cannot be used to estimate the magnitude of dioxin and furan
emissions, nor can they be used to determine with certainty that dioxins and
furans are present in the emissions.
The second level of testing involves stack testing. A limited number of
combustion source categories has been selected for detailed source testing
(i.e., stack sampling), as shown in Table 1. Because of the costs involved
with stack testing, only 10 to 12 individual sources can be tested within the
available budget. These tests are being performed using procedures consistent
with those described by the American Society of Mechanical Engineers (ASME) in
its sampling protocol for energy recovery facilities, which is now under final
development.
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Table 1. Combustion Source Categories Where Ash
And Stack Samples Will Be Collected *
Source Categories Samples To Be Collected
Sewage Sludge Incinerators
Black Liquor Recovery Boilers
Industrial Incinerators
Wire Reclamation Incinerators
Chemical Sludge Incinerators
Industrial Carbon Regeneration Units
Hospital Incinerators
Charcoal Manufacturing Oven
Wood Stoves
PCP Treated And Salt Laden
Wood-Fired Boilers
Small Spreader-Stoker Coal -Fired Boilers
-Kilns And Commercial Boilers Burning
Hazardous Wastes
Residential Contaminated Oil Combustion
Forest Fires
Apartment House Flue-Fed Incinerators
Agricultural Burning
Ash
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Stack
X
X
X
X
X
X
X
X
* This includes some samples and results being supplied to
Tier 4 by other programs.
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Samples being collected for the stack testing program include stack emis-
sion samples (both before and after controls), ash samples from the control
device and firebox ash hoppers, samples of the feed or fuel precombustion air
and samples of nearby soils. Most samples are being analyzed for the 2378-TCDD
and 2378-TCDF isomers and for each of the higher homologues of dioxins (i.e.,
tetra, penta, hexa, hepta, octa) and furans. A summary of the samples typi-
cally being collected during stack testing and the analyses to be performed
under Tier 4 is shown in Table 2.
At the conclusion of the Tier 4 study, the Agency will have collected
either ash samples or detailed stack samples from a number of combustion source
categories. Further, the results of studies being conducted by others will be
summarized in the final Tier 4 report. For example, the stack test data being
collected from various municipal incinerators by New York State and others will
be included, if available. Any preliminary results from the $3 million, three-
year effort being initiated by Environment Canada to examine the significance
of various operating conditions on dioxin emissions from municipal incinerators
will be of particular interest. The final Tier 4 report will also include a
list of recommendations for future testing and study will be provided at that
time, if warranted.
Schedule And Status Of Tier .4
Tier 4 is operating under a fairly tight schedule. Figure 1 outlines the
discrete components of the Tier 4 plan and the schedule for each. As of this
date, the literature review and the Tier 4 Work Plan are complete and in the
process of being cleared and publicly distributed. Analytical results of
samples taken thus far in the program are not yet available.
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Tabl e 2. Example Dioxin Sample Prioritization
Sample Location
Sludge Feed
Ambient Combustion Air
Fuel Oil
Incinerator Outletb
Incinerator Bottom Ash
Scrubber Slurry Slowdown
Stack Outlet5
Soil
Blank Train
Sample Type
Grab Sample Composite
XAD-2 Trap
Grab Sample Composite
MM5 Component
Grab Sample Composite
Aqueous Grab Sample Composite
MM5 Components
Grab Sample Composite
MM5 Components
Samples
Collected
3
3
3
3
3
3
3
1
2
Analysis
Priority
2
2a
3
2a
1
la
la
3
1/2- .c
a Aqueous phase sample or components should be extracted within 14 days of sample
collection.
b Incinerator outlet is before controls. Stack outlet is after controls.
c Two blank trains collected. One is designated priority one. The second will
be analyzed only if the first blank train has detectable background levels of
dioxin/furans.
Note:
Priority 1 indicates analyses should be performed for 2378-TCDD and 2378-TCDF
plus higher (tetra-octa) homologues of dioxins and furans. If there is a
detectable concentration, Priority 2 samples are to be analyzed. Priority 3
samples may be analyzed on a case-by-case basis if Priority 2 samples have a
positive response.
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Figure 1. Schedule: National Dioxin Study - Tier 4 - Combustion Sources
1983 1984 1985 1986
Activities NDJFMAMJJASONDJFMAMJJASONDJFMAMJ
Begin project
Tier 4 Work Group Meeting*
Perform literature review
Develop Tier 4 work plan
Select sources for ash
screening
Select individual sources
for stack testing.
Ash and stack sample
collection and analysis
Prepare individual source
test plans; conduct source
testing and prepare source
test reports.
Prepare draft Tier 4 report
0
Draft Final
Draft Final
0. , __. -__--
0__ _. __..
Draft Fin<
o o o
il
Tier 4 Work Group will meet periodically throughout the study period.
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A number of specific objectives and steps have been accomplished under the
first year of Tier 4 efforts. These are listed and discussed below.
o Coordination with EPA Regional Offices has been established. Tier 4
Regional contacts have been formally designated.
o A Tier 4 Work Group, comprised of representatives of various EPA Program
Offices and the Regions, has been established to assist in formulation and
review of plans.
o A literature review and data assessment of available dioxin related
information from combustion sources has been completed.
o A Tier 4 Project Plan has been drafted, extensively reviewed (both
internally and externally), and finalized for distribution.
o Sampling protocols have been developed, reviewed and adopted for Tier 4
stack sampling and ash sampling programs.
o Arrangements have been made with EPA's Troika (dioxin analysis labora-
tories) for Tier 4 to be provided approximately 700 laboratory analyses for
2378-TCDD, 2378-TCDF and tetra through octa dioxin and furan homologues.
o Community relations plans and press releases, as well as "Dioxin Tier 4
Study" fact sheets, have been coordinated and distributed in conjunction with
the Office of External Affairs.
o Contact and continued coordination has been established with Canadian
authorities to provide data to result from studies they have underway. Results
of the first of their three test site studies should be available for use by
Tier 4.
o Contact and continued coordination with New York State has been estab-
lished regarding testing of municipal incineration underway there.
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o Coordination with EPA Region V on their dioxin testing at the DOW,
Midland, Michigan, facility is continuing.
o Site selection for Tier 4 testing is at an advanced stage, with many
sources voluntarily providing a test site and others where Section 114 of the
Clean Air Act will likely be needed for site entry.
o Stack and ash testing have begun and are on schedule. Current status
is as follows:
Stack Ash
Total Samples Planned 11 50
Sites Selected 4 (36%) 10 (20%)
Tests Completed 4 (36%) 10 (20%)
Validated Test Results Received 0 0
In addition to the above, the Agency has progressed on its schedule con-
cerning a decision whether dioxins should be listed as hazardous air pollutants.
Also, EPA has spent considerable effort in preparing response to a petition
filed jointly by the Environmental Defense Fund and the National Wildlife
Federation for the regulation of dioxins.
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References
1. The Trace Chemistries Of Fire - A Source Of And Routes For The
Entry Of Chlorinated Dioxins Into The Environment, Dow Chemical, U.S.A.,
Midland, Michigan, 1978.
2. National Dioxin Study: Tier 4 - Combustion Sources: Literature
Reviews And Testing Options (In Printing), EPA-450/4-84-014b, U.S. Environ-
mental Protection Agency, Research Triangle Park, North Carolina, December
1984.
3. M. P. Esposito et a!., Dioxins: Volume 1 - Sources, Exposure,
Transport And Control, EPA-600/2-80-156, U.S. Environmental Protection
Agency, Cincinnati, Ohio, June 1980.
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