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40 CFR Parts 260, 26 T, 264, and 270
Standards for Owners and Operator&gf
Hazardous Wastes Iniesneratbrs and ^
Burning of Hazardous; Wastes in Boilers
and Industrial Furnaces; Proposed and
Supplemental Proposed Rule, Technical
Corrections, and Request for Comments
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15TC62
Federal Register ) Vol. 55, No; 82*'/ Fniday.^pril 27', 1990 / Proposed Rules
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Parts 260,261,264 and 270
lFRL-3358-« EPA/OSW/FR/90-007]
RIN 2050-AB90
Standards for Owners and Operators
of Hazardous Waste Incinerators and
Burning of Hazardous Wastes In
Bolters and Industrial Furnaces
AGENCY: Environmental Protection
Agency.
ACTION: Proposed rule, supplemental
proposed rule, technical corrections, and
request for comments.
SUMMARY: Under this proposal, the
Environmental Protection Agency (EPA)
would amend the hazardous waste
incinerator regulations to improve
control of toxic metal emissions,
hydrogen chloride emissions, and
residual organic emissions; amend the
definitions of incinerators and industrial
furnaces; propose definitions for plasma
arc incinerators and infrared
incinerators; propose to regulate carbon
regeneration units as thermal treatment
devices; and make a number of minor
revisions to permitting procedures.
At present, toxic metal emissions from
incinerators are controlled indirectly by
a limitation on participate matter. Under
some conditions, the participate
standard may not sufficiently control
toxic metals to ensure adequate
protection of human health. Under
today's proposal, EPA would establish
risk-based emission limits for individual
toxic metals in addition to the existing
participate standard.
Under existing rules, hydrogen
chloride emissions are controlled by a
technology-based standard. Because
that standard may under-regulate
emissions in particular situations, risk-
based emissions limits would be
established in addition to the existing
standard.
In addition, organic emissions that
result from inadequate combustion of
toxic organic hazardous wastes are
controlled under present rules by a
destruction and removal efficiency
(DRE) standard. The DRE standard
requires destruction of toxic organic
constituents in the waste, but does not
directly control products of incomplete
combustion. To address the potential
health risk from products of incomplete
combustion, today's proposed rule
/vould require that incinerators
continuously operate at high combustion
efficiency by establishing limits on flue
gas carbon monoxide and hydrocarbon
levels.
Finally, EPA is noticing technical
corrections as well as requesting
comment on three regulatory
alternatives to issues presented in the
October 26,1989 supplement to the
proposed ride for burning hazardous
waste hi boilers and industrial furnaces
(54 FR 43718). These items are set forth
in part One, section III.C of this notice.
The issues of concern are: regulation
during interim status of the direct
transfer of hazardous waste from a
transport vehicle to a boiler or furnace;
controls on emissions of free chlorine;
and limiting stack gas temperature at
the inlet to a dry emissions control
device to below 450 °F.
DATES: EPA will accept public
comments on this proposed rule and on
the other issues opened for public
comment by this notice until June 26,
1990.
ADDRESSES: Comments on this proposed
rule, including the boiler and furnace
supplemental issues, should be sent to
RCRA Docket Section (OS-305), U.S.
Environmental Protection Agency, 401M
Street, SW., Washington, DC 20460
ATTN: Docket No. F-90-BWIP-FFFFF.
The public docket is located in Room
2427 and is available for viewing from 9
a.m. to 4 p.m., Monday through Friday,
excluding legal holidays. Individuals
interested in viewing the docket should
call (202) 475-9327 for an appointment.
FOR FURTHER INFORMATION CONTACT:
RCRA HOTLINE, at (800) 424-9346 (toll
free) or at (202) 382-3000. Single copies
of the proposed rule are available by
calling the RCRA Hotline. For technical
information, contact Shiva Garg,
Combustion Section, Waste
Management Division, Office of Solid ,
Waste, OS-322, U.S. Environmental
Protection Agency, 401M Street, SW.,
Washington, DC 20460, Telephone: (202)
382-7924.
SUPPLEMENTARY INFORMATION:
Preamble Outline
PART ONE: BACKGROUND
I. Legal Authority
II. Overview of the Proposed Rule
A. Toxic Metals
B. Hydrogen Chloride
C. Control of Products of Incomplete
Combustion
D. Definitions
E. Permitting Procedures
F. Halogen Acid Furnaces
in. Relationship of the Proposed Rule to
Other Rules
A. Existing Hazardous Waste Incinerator
Standards
B. Other Related Actions
C. Technical Corrections To The October
26,1989, Boiler/Furnace Supplemental
Notice and Request For Comment On
" Regulatory Issues
1. Technical Corrections.
2. Requpst for Comment on Regulatory
Issues.
D. Proposed Definition of Sludge Dryer
IV. Need for Controls
A. Risks From Toxic Metals Emissions
B. Risks From Hydrogen Chloride
Emissions
C. Potential Risks From Products of
Incomplete Combustion (PICs)
PART TWO: REGULATORY OPTIONS
CONSIDERED
I. Particulate Emission Limits
A. Consideration of Controlling Metals
with a Particulate Standard
B. Consideration of a More Stringent
Particulate Standard
II. Definitions of Incinerators and Industrial
Furnaces
A. Definition of Incinerator and Industrial
Furnace
1. Revised Definition of Industrial
Furnace.
2. Plasma Arc and Infrared Devices are
Incinerators.
3. Fluidized Bed Devices are Incinerators.
4. Revised Regulatory Status of Carbon
Regeneration Units.
B. Regulation of All Thermal Treatment
Units Under Subpart O
PART THREE: DISCUSSION OF PROPOSED
CONTROLS
I. Overview of EPA's Risk Assessment
A. Overview of the Risk Assessment
Approach
B. Identification of Reasonable Worst-Case
Incinerators by Terrain Type
1, Factors Influencing Ambient Levels of
Pollutants.
2. Selection of Facilities and Sites for
Dispersion Modeling
C. Development of Dispersion Coefficients
D. Evaluation of Health Risk
1. Risk from Carcinogens
2. Risk from Noncarcinogens.
E. Risk Assessment Assumptions
F. Risk Assessment Guideline
H. Proposed Controls for Emissions of Toxic
Metals
A. Overview
B. Metals of Concern
1, Chromium.
2. Nickel.
3. Selenium.
C. Metals Emissions Standards
D. Screening Limits
III. Proposed Controls for Emissions of
Hydrogen Chloride
A. Summary of Existing Standard
B. The Existing Standard May Not Be Fully
Protective in Certain Situations
C. Request for Comment on Controls for
Free Chlorine
D. Basis for Proposed Standards
IV. Proposed Controls for Emissions of
Products of Incomplete Combustion
A. Hazard Posed by Emissions of Products
of Incomplete Combustion (PICs)
B. Existing Regulatory Controls
C. Basis for CO Standards
1. Summary of Proposed Controls
2. Use of CO Limits to Ensure Good
Combustion Conditions.
D. Derivation of the Tier I CO Omit.
E. Derivation of the Tier II Controls.
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27, 1990 / Prqposqii Rules
17863
1. Health-Based Approach.
2. Technology-Based Approach.
a; Concerns with-the THC Risk
\ssessmentMefhodology.
.Basis for the HG Limit,
f. Implementation of Tier I and Tier tt PIG
Controls,
1. Oxygen and" Moisture Correction. .
2. Formats of the CO timit.
3. Monitoring CO and Oxygen.
4. Monitoring HC.
5. Compliance with Tier! CO Limit.
6. Establishing Permit Limits for CO under
Tierll.
7. Compliance with HC Limit of 20 ppmv
8, Waste Eeed Cutoff Requirements.
G. Request for Comment on Limiting APCD
Inlet Temperatures
PART FOUR: PERMIT PROCEDURES AND
OTHER ISSUES .
I. Impact oh Existing Permits
II. Waste Analysis Plana.and Trial Burn
. Procedures
A. Waate Analysis Plans
B. Trial Burn Procedures: • .
III. Emergency Release Stacks
IV. POHC Selection
V. POHC Surrogates
VI. Information Requirements
VII. Miscellaneous Issues
VIII. Halogen Acid Furnaces
PART FIVE: ADMINISTRATIVE,
ECONOMIC AND ENVIRONMENTAL,
IMPACTS .
I. State Authority ' ;
A. Applicability of Rules in Authorized
States
B. Effecrt on State Authorizations
If. Regulatory Impact Analysis
A. Purpose-and Scope . ,
B. Affected Population.
C. Costing, Analysis
1. Costing Methodology and Unit Costs, of
Control
2. Results
D. Economic Impact Analysis
•1. Methodology
2. Results
F. Risk Assessment •-•:.-—
1. Methodology,
2. Results
G. Regulatory Flexibility Analysis
1. Methodology
2. Results -
H. Paperwork Reduction: Act
Ifl. Pollution Prevention Impacts
IV. List of Subjects in 40 CFR Parts. 260, 264,
and27Q *
Appendix Ar Measurement of MetaLs and
Hydrogen Chloride ^
Today's preamble, is organized in five
major parts. Part One contains
background information that
summarizes major provisions of the rule.
It also describes how today"? rule fits
into the Agency's strategy for regulating
all burning of hazardous was^e. Finally,
this part identifies the need for
increased regulatory controls beyond
the present hazardous waste incinerator
'•Rgulations, - -
PaVTwo discusses why the proposed .
controls limit emissions'based on risk
assessment rather than using '•"..'•
technology-based standards. Part Two
also discusses the proposed definitions
for incinerators, industrial furnaces, and
plasma arc and infrared incinerators;
the regulation of carbon regeneration
units as thermal treatment devices; and
minor revisions to existing permitting
requirements.
Part Three discusses the proposed' ^
revisions to the existing emissions
standards. It explains EPA's use of risk
assessment to develop the proposed
rule; describes conservative screening
limits for toxic metals, hydrogen
chloride, and total hydrocarbons; and
explains how site-specific dispersion
modeling would be used to establish
emission: limits when the screening
limits are exceeded.
Part Four discusses the permit
procedures that would be used to
'- implement the controls, and also
discusses issues regarding the already
proposed listing of halogen, acid
furnaces as industrial furnaces under
§ 260.10. This section also explains the J
impact of these proposed rules on
existing permits and the added
information requirements* Sampling; arid
analytical procedures that may be used
to analyze wastes for metals and to-
determine actual metal emissions during
trial burns are also discussed. In
addition, this part discusses a number of
proposed revisions to permitting
procedures that would clarify
ambiguities and provide more flexibility
to applicants and permit writers.
Part Five discusses the applicability of
the rules in authorized States and their
effect on State-authorizations-. This part
also discusses the economic impacts the
rule would have on the regulated
community. .- . •
PART ONE: BACKGROUND ''•'
I. Legal Authority
These regulations are proposed under
authority of sections 10G&, 2002, 3001,
through 3007, 3010, and 7004 of the Solid
Waste Disposal Act of 1970, as amended'
by the Resource Conservation and
Recovery Act of 1976, the Quiet
• Communities Act of 1978, the Solid
Waste Disposal Act Amendments of
1980, and the Hazardous and Solid
Waste Amendments of 1984,42 U.S.C.
6905",. 6912, 6921 through 6927, 6930, and
6974. •'"-;--'
II. Overview- of the Proposed Rule
EPA proposes today to amend the
hazardous waste incinerator regulations
at40CFRpart264,subpartO,part260 '
and part 261r and the associated permit
rules at 40 CFR part 270 to provide
improved control of toxic metals
-—••;,, •:~-:-~-~:^~™~-^i~-j--,~'.~;-:-j*~.~:-t,j i«-i^.,*i.%S3SffiSH4:U^.4.-i
emissions, hydrogen chloride emissions
and residijal organic emissions. EPA.
also proposes to definition for sludge
dryers and a revised definition for
industrial furnaces. Minor amendments:
to a number of permitrequirements are
also proposed.
.''!•'
-A. Toxic Metals
Wastes bearing high levels of metals
are commonly burned in incinerators
[spent solvents and their still bottoms
are examples). Metals and metal
compounds in hazardous waste are not
destroyed by incineration: but are
transformed into other metal species
(usually oiiddes} and then either are
removed sia ash or in scrubber water,: or
are emitted with stack gases. Metals are
usually eniitted as particulates, but cane
be emitted as metal vapors if the metal
is volatile.^
EPA hast conducted'risk assessments
to determine the levels of toxic metals.
that would create an unacceptable risk
to human health if released to the. :
atmospheie. EPA's analysis indicates
that .the present hazardous waste
incineratoif participate standard of 0.08
gram per clry standard cubic foot (180
milligrams per dry standard cubic meter}
may not adequately control emissions of
toxic metals.?
In 1982 and 1983, EPA conducted field
studies on eight incinerators to quantify
emissions of pollutants. The Agency
then evaluated the risk posed by those -
emissions and concluded mat metals-
emissions probably did not present an
unacceptaiale level of risk. However, the
metals levels in the waste feed to the
incinerators in these tests were •
relatively low. Emissions from
incinerators burning waste with high
levels of metals have not been
determined in actual field tests. Thus,
the Agency is concerned that, under
conditions of high concentrations of
toxic metals in waste and inadequate
flue gas cleaning methods, the potential
for unacceptable levels of risk could
exist at some incinerators.
After considering the options for
limiting such potential risk, the Agency
is proposing to establish risk-based
emission limits for the Individual toxic,
metals listed in. Appendix. VTH of 40, CER
part 261. Tlie limits would be back-
calculated from, ambient levels that EPA.
believes pcise acceptable health, risk. To,,
reduce the burden to the applicant and
permitting officials, EPA has developed
conservative Screening Umits. If the
1 Mitre Corp. "Mitre Working Paper. Hazardous
Waste Stream Trace Metal Concentrations and
Emissions." UiSEPA^ Office- of Solid Waste:
Novemberl98S.
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178S4
Federal' Register / Vol. 55, No. 82 /
/ Pr°Posed Rules
Screening Limits are not exceeded,
emissions do not pose unacceptable
risk. If the Screening Limits are
exceeded, however, site-specific
dispersion analysis would be required to
demonstrate that emissions would not
result in an exceedance of acceptable
ambient levels.
B. Hydrogen Chloride
EPA's present standard for control of
add gas at 40 CFR 264.343(b) requires
that the rate of emission of hydrogen
chloride (HCl) be no greater than the
larger of 1.8 kilograms per hour (4
pounds per hour) or 1 percent of the HCl
in the stack gas before entering any
pollution control device. EPA believes
that this standard may not be protective
of public health in some instances.2
Thus, EPA is proposing to regulate HCl
under the same risk-based approach
proposed for metals. The risk-based
controls would be used on a case-by-
case basis to ensure that the existing
technology-based standard is protective.
C. Control of Products of Incomplete
Combustion
Existing regulations control organic
emissions by the destruction and
removal effeciency (DRE) standard at 40
CFR 264.343(a). This standard limits
stack emissions of principal organic
hazardous constituents (POHCs) to 0.01
percent (0.0001 percent for dioxin-
containlng waste) of the quantity of the
POHC fed to the incinerator. The
standard considers a POHC to be
destroyed (or removed in ash or
scrubber water) if it is not present in the
stack emissions. EPA's concern is that
although the POHC itself may not be
present at significant levels,
intermediate combustion products, or
products of incomplete combustion
(PICs), may be present at levels that
could pose significant health risk. The
complete combustion of all
hydrocarbons to produce only water and
carbon dioxide is theoretical and could
occur only under ideal conditions. Real-
world combustion systms (e.g..
incinerators, fossil fuel steam
generators, diesel engines), however,
virtually always produce PICs, some of
which could be highly toxic.
EPA believes that requiring
incinerators to operate at high
combustion efficiency is a prudent
approach to minimize the potential
health risk posed by PIC emissions.
Given that stack gas CO is a
conventional indicator of combustion
efficiency and a conservative indicator
* VS. EPA, 'Technical Background Document:
Control of Metal* and Hydrogen Chloride Emissions
from Hazardous Waato Incinerators." August 1989.
of combustion upsets (i.e., poor
combustion conditions), today's rule
would limit CO emissions to a de
minimis level that ensures high
combustion efficiency and low unburned
hydrocarbon emissions. In cases where
the de minimis CO limit is exceeded, the
owner or operator would be required to
demonstrate that higher CO levels
would not result in high hydrocarbon
emissions. We are taking comment on
two alternative approaches to ensure
that hydrocarbon emissions are ,
acceptable: (1) A demonstration that
hydrocarbon emissions are not likely to
pose unacceptable health risk using
conservative, prescribed risk
assessment procedures; or (2) a
technology-based demonstration that
the hydrocarbon concentration in the
stack gas does not exceed a good
operating practice-based limit of 20
ppmv. Although we prefer the
technology-based approach for reasons
discussed below, we request comment
on the health-based alternative as well.
D. Definitions
EPA is today proposing revised
definitions for industrial furnaces and
incinerators and new definitions for
infrared incinerators and plasma arc
incinerators. These definitions would
include infrared and plasma arc
incinerators within the definition of
incinerator, and include nonflame
combustion devices within the definition
of industrial furnaces. EPA also
proposes to regulate both direct flame
and nonflame carbon regeneration units
as thermal treatment units and, because
of ambiguity regarding the current
regulatory status of flame units, to
establish the date of promulgation as the
"in existence" date for interim status.
EPA is also taking comment on an
alternate regulatory approach that
would simply regulate all types of
hazardous waste thermal treatment
devices (e.g., incinerators, boilers,
industrial furnaces) under one set of
standards, subpart O of parts 264 and
265.
E. Permitting Procedures
The EPA is today proposing to make a
number of revisions to current
permitting procedures. The purpose of
these revisions is to clarify ambiguities
in the present regulations and to give the
permit writer flexibility in implementing
the rules while providing adequate
protection of public health. Examples of
these changes include: all hazardous
waste combustion units at a site would
be considered when implementing the
risk-based controls proposed today;
compounds may be chosen as POHCs
' even though they may not be on
appendix VIII or in the waste (at the
permit writer's discretion); information
relating to emergency relief valves and
their use must be provided in the part B
application; automatic waste feed
cutoffs must be noted in an operating log
and reported on a quarterly basis; and
temperature must be maintained in the
combustion chamber until all wastes
(and residues) exit the chamber.
We note that EPA has already
published at 54 FR 4286 (January 30,
1989) clarifications to 40 CFR 270.62(d)
which better reflect the initial intent of
the regulations with regard to requiring
existing incinerators either to complete
a trial burn, or submit data in lieu of a •
trial burn, prior to permit issuance.
F. Halogen Acid Furnaces
On May 6,1987, EPA proposed to add
Halogen Acid Furnaces (HAFs) to the
list of industrial furnaces under § 260.10.
See 52 FR 17018. We are today
requesting comment on revisions to the
proposed definition of HAFs to better
distinguish between HAFs and
incinerators burning halogenated waste.
In addition, we are proposing to list as
inherently waste-like under § 261.2(d)
any secondary material fed to a HAF
that is identified or listed as a
hazardous waste under part 261,
subparts C or D. Without that listing,
HAFs burning wastes solely as an
ingredient (i.e., wastes that have low
heating value and, so, are not burned
partially for energy recovery) to produce
acid gas would be unregulated under
§ 261.2(e)(l)(i). Wastes, with high heating
value (i.e. greater than 5,000 Btu/lb),
however, are considered to be burned at
least partially for energy recovery and,
thus, would be subject to the proposed
boiler and industrial furnace rules.
III. Relationship of the Proposed Rule to
Other Rules
A. Existing Hazardous Waste
Incinerator Standards
The permit standards for incinerators
now in effect at 40 CFR part 264, subpart
O, establish three performance
standards. The Agency believes that
these standards may not be adequately
protective in all cases and, thus, is today
proposing to strengthen the standards.
Incinerators burning hazardous waste
must achieve a destruction and removal
efficiency (DRE) of 99.99 percent for
each Principal Organic Hazardous
Constituent (POHC) designated for each
waste feed. This approach was based
upon data indicating the hazardous
waste incinerators burning a wide range
of organic hazardous wastes could
achieve such a destruction efficiencv
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Federal Register / Vol. 55, No. 82 /Friday, April 27;. 1990 / Proposed RulesT
17885';
and risk assessments indicating levels of
unburned POHC would not pose an
unacceptable health risk, .
Metals emissions are controlled:
indirectly by a particulate matter
emissions limit of ISO milligrams per dry
standard cubic meter (or 0.08 gr/dscf).
Fmally, hydrogen chloride (HCl)
emissions are controlled by a standard
that requires emissions, to be reduced by
99 percent if emissions exceed 4 Ib/hr.
This standard is based upoa the .
expected HGl removal efficiency from .
existing wet scrubber technology.
3. Other Related Actions
The Agency has promulgated some
regulations and proposed others for the
burning of hazardous waste fii boilers
and industrial furnaces that would
ensure that combustion controls and'
emissions standards are identical for
boilers, .industrial furnaces, and
incinerators.
On January 4,1985, EPA revised ita
rules to state that listed hazardous .
wastes and sludges are subject to
transportation and storage controls prior
to their being burned as fuels in boilers
and industrial furnaces and prior to their
processing or blending to produce a
waste-derived fuel (50 FR 665), On.
November 29,1985, EPA promulgated
administrative controls for marketers.
and burners of hazardous waste fuels
(50 FR 491641 that included a provision
regulating transportation and storage of
any hazardous waste used as a fuel or .
used to produce a fuel.
On May 6,1987; EPA proposed rules
that would- establish technical (i.e.,
emissions} controls for boilers and:
industrial furnaces burning hazardous
waste (52 FR 16982). The proposed
boiler and industrial furnace rules
would extend the concept of risk
assessment to establish national
performance standards to control stack
emission of metals and hydrogen
chloride (HCl) and would control
products of incomplete- combustion by
limiting flue gas carbon monoxide'
levels. The rules would also require a
DRE of 99.99 percent to be
demonstrated:.
On October 26,1989, EPA published to
the Federal Register (54 FR 43718} a
supplemental notice to the May 1987'
proposed rule. That notice requested
comment On alternative approaches to •
address the following issues: control of
PIC emissions by limiting, flue gas ,
concentrations of CO and hydrocarbons;
control of metals, HCl and particulate
emissions^ the smatt quantity burner
exemption; the definition of waste that
•is indigenous'when: processed for. ,
reclamation; applieabflify-of the
proposed metals and organic emissions
controls to smelting furnaces involved in
materials recovery; and the status under
the Bevill amendment of residues from
burning hazardous waste. The PIC,
metals, and HCl emission controls
proposed today for incinerators are
identical to those which the Agency
proposed for boilers and industrial
furnaces in the October 1989
supplemental notice. As discussed
below, the Agency is also today-making
several technical corrections to the
October 1989 notice. La addition, the
Agency is requesting comment on
several regulatory issues pertaining to
boilers and industrial furnaces burning-
hazardous waste.
We note that EPA is also proposing
today to amend, the definition of
industrial furnace to include devices
that otherwise meet EPA's criteria for
classification as an industrial furnace
but that are heated by means other than
controlled flame combustion (e.g.,
-electric arc, smelting furnaces]. See
section IE of part Two. Moreover, we
are also requesting comment today on
whether and how to regulate all
hazardous waste thermaltreatment
devices (e.g., incinerators, boilers, and _
industrial furnaces) under parts 264 and;
265, subpart O. Under this regulatory
scheme, we may be able to eliminate the
need for the sometimes ambiguous
distinction between boilers; industrial
furnaces, and incinerators and the
redundant regulatory language that
would occur if we promulgate boiler and
industrial furnace regulations fpart 266,
subpartDJ as proposed, that are
virtually identical to existing and
proposed regulations for incinerators-.
Finally; we note that we are
requesting comments -on several- issues
regarding the proposed listing (52 FR
17018) of halogen acid furnaces as
industrial furnaces under § 260.101
C'. Technical Corrections To The
October 2&r 1989, Boiler/Furnace
Supplemental Notice And Request FOE
Comment On Regulatory Issues,
For convenience and because-today's:
proposed amendments to the incinerator
standards are closely related to the
Agency's proposed boiler and industrial
furnace rules, the Agency is using
today's notice to make several technical-
corrections to the October 26,1989^
supplemental notice (54 FR 43718}. We
are also requesting comment on several.
additional; regulatory issues and are
'reopening the comment period on the
supplemental notice ta take comment-on
these issues, - -, ' •;'..
1. Technical Corrections. The Agency
is making the following corrections to
FRL-3358-5EPA/QSW-FR-89-OZ4,
" Supplement to PtpposedrRule for ; •
Burning of Hazardous Waste in. Boilers
and Industrial Furnaces (54 FR 4371ft
(October 26,1989}Jr
a. On page 43720 .under the heading.
"3.. Apply Existing Hazardous Waste
Incinerator Standard",, the cite should be
40 CFR 2l34:343(c)w not 40 CFR 340.342(c).
b. On page 43731, the second equation
should read:
! I4Q
<1
c. On gage 43757, footnote 56 •
referencing the source for the HCl RAG
of 7 ug/m3 should read "Memo dated
May 4,1989, from Mike Dourson, EPA
Office ©I Health and Environmental
Assessment, to the RfD Workgroup,
entitled "RfD Meeting of Februaryl6,
1989". . | ' .
d. On piage 43762 in Appendix I, the
long-term (i.e., annual), exposure RAC
for HCl should be 7 fAg/m3, the 3-minute,
exposure RAC for HCl should be150
fig/m3, and the RAC for mercury should
be 0.3 ju,g/m3.
e. On page 43763 in Appendix J, the
unit risk ifor beryllium, should be 2.4E-03
m3//ig and the unit risk for a n-nitroso-H.-
methylurea should be 8^6 E-02 m3/jig.
2. Request forComment on ,
Regulatory Issues. The Agency is
reopening the comment period on, the
October 26,1989, supplemental notice to
' take comment on three issues: (a) the
regulation during interim status of the
direct transfer of hazardous; waste from
a transport vehicle to a boiler, or >
furnace; (b), controls on emissions of free
chlorine; and (cjiumiting; stack gas
temperature at the inlet to a dry
emissions control device (e.g.* bag
house, ESP) tO'45&0F. (We note that we
are reopening, the comment period for ;
the October 26,1989, supplemental
npticeto receive comment on these
issues only.) •
a. Transfer Operations. In the October
26 supplemental notice (see page 43736),
the Agency requested comment on two
approach es to regulate direct transfer
operations: (1J permit writers could use
the omnibus authority provided by the
statute to establish additional permit
conditions as necessary to ensure
, adequate iprotecfion of human health
and the environment from such
•operations? and (2) a requirement that
all facilities that burn hazardous waste
use.blencliiig and surge storage tanks to ,
avoid: flow interruptions and waste
stratificaiiion.jwhich, m turn, could affect
the abilit,j? of the combustion: device to ,
-meetthe performance standards.
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Federal Register / Vol. 55, No. 82 / Friday, April 27, 1990 / Proposed Rules
During the comment period for the
boiler/furnace supplemental notice,
commenters suggested that blending/
surge storage tanks were not necessary
to ensure compliance with performance
standards. This issue will be discussed
further in the promulgation of the final
boiler/furnace rules. Commenters also
stated, however, that controls on
transfer operations were needed during
interim status. They noted that it could
take several years for the States or the
Agency to issue a final permit to a boiler
or furnace facility with a direct transfer
operation. They argued that controls
%vere needed in the interim to ensure
adequate protection of human health
and the environment from spills, fires,
explosions, and toxic fumes. We agree
and are today requesting comment on
regulating direct transfer operations
under the appropriate interim status
standards for containers and tank
systems provided by Subparts I and J of
40 CFR part 265. The other nontechnical
standards for interim status facilities
could also be applied, as applicable,
including subparts A, B, C, D, E, G, and
H.
These standards would become
effective at the same time that the
interim status standards become
effective for the boiler or furnace—six
months after promulgation.
The transport vehicle, once connected
to the boiler or furnace firing system,
could be subject to the Subpart I
container standards. The once-a-week
inspection frequency provided by
§ 205.174, however, could be revised to
require daily inspection.
The piping system from the transport
vehicle to the boiler or furnace could be
subject to the tank system standards of
Subpart J. We note that the compliance
dates provided by Subpart J could be
revised to reflect the date of
promulgation of a final rule.
In the final rule, we could revise the
subpart I and J standards as indicated
above and include them under the
boiler/furnace rules in subpart D of part
260.
The Agency requests comments on the
need to regulate transfer operations
during interim status and whether the
suggested revised standards would be
appropriate. The date of the final rule
would be the "in existence" date for
purposes of interim status qualification.
b. Controls for Emissions of Free
Chlorine (CU). As discussed in section
HUB. of today's proposal, we are
concerned that CU could be emitted
from burning chlorinated wastes if there
was insufficient hydrogen available (i.e.,
from other hydrocarbon compounds or
water vapor) to react with all the
chlorine in the waste. To address this
problem, we are requesting comment on
whether to require owners and
operators of boilers and industrial
furnaces burning hazardous waste to
demonstrate that the maximum exposed
individual (MEI) is not exposed to Clz
concentrations exceeding an annual
average reference air concentration
(RAG) of 0.4 jitg/m3.3 The Clz RAG is
based on 100% of the interim inhalation
RfD because other sources of Clz are
expected to have little or no effect on
background levels due to the short life of
Clz in the atmosphere. This approach is
consistent with the approach EPA
proposed for HC1. As with the HC1
standards, compliance could be
demonstrated by: (1) emissions testing
and dispersion modeling; (2) emissions
testing and conformance with C12
emissions Screening Limits; or (3) waste
analysis and conformance with chlorine
feed rate Screening Limits.
The Cl2 Screening Limits could be
developed using the same methodology
used for the metals Limits [e.g., same
dispersion or dilution factors; feed rate
limits assume all chlorine in the feed is
emitted as Clz). (The dispersion factors
used to establish the HC1 Screening
Limits would not be appropriate
because they are based on short-term
(i.e., 3-minute) exposures. A short-term
RAG is not yet available for Clz.) Given
that the RAG for Clz is 1.33 times the
RAG for mercury, the Screening Limits
for Clz would be 1.33 times the Limits
established for mercury in Appendix E
of the boiler/furnace supplemental
notice.
Emissions testing for Clz should be
conducted in accordance with "Draft
Method for Determination of HC1
Emissions from Municipal and
Hazardous Waste Incinerators", U.S.
EPA, Quality Assurance Division, July,
1989. In using this method for Clz •
determination, caustic impingers must
be used after the water impingers in the
sampling train. The caustic solution will
then be analyzed for chloride and
reported as chlorine.
c. Limiting APCD Inlet Temperatures.
We are requesting comment on whether
to limit the temperature of stack gas
entering a dry emissions control device
(e.g., bag house, electrostatic
precipitator (ESP)) to minimize
formation of chlorinated dibenzodioxin
and dibenzofurans (CDD/CDF). After
conducting extensive emissions testing
of municipal waste combustors (MWCs),
the Agency has concluded that CDD/
CDF can form on MWC flyash in the
presence of excess oxygen at
temperatures in the range of 480 to
750°F.* Cooling the flue gases and
operating the air pollution control device
(APCD) at temperatures below 450°F
helps minimize the formation of CDD/
CDF in the flue gas. Thus, the Agency
has recently proposed to limit MWC
stack gas temperatures at the inlet to the
APCD to 450°F. See 54 FR 52251
(December 20,1989).
Given that some hazardous waste
incinerators and boilers and industrial
furnaces burning hazardous waste are
equipped with dry particulate control
devices, we request comment on the
need to control gas temperatures to
450°F to minimize CDD/CDF formation.
Although available delta indicate that
CDD/CDF emissions from hazardous
waste combustion devices are much
lower than can be emitted from MWCs,5
it may be prudent to limit gas
temperatures in hazardous waste
combustion devices as well.
E. Proposed Definition of Sludge Dryer
We note that the Agency plans to
discuss the regulatory status of sludge
dryers and propose a new definition for
such devices in a separate Federal
Register notice. This definition would
distinguish between sludge dryers and
incinerators. In that notice, the Agency
also will propose to revise the definition
of incinerator to exclude sludge dryers
that may otherwise meet the definition
of incinerator. We summarize below the
discussion the Agency plans to present
in that notice.
The notice will clarify the current
regulatory status of sludge dryers: (1)
sludge dryers that meet the § 260.10
definition of a tank 6 and a wastewater
3 Memo from Priscilla Halloran, EPA, to Dwight
Hlustick, EPA, entitled "Health-Based Air
Concentrations for Chlorine and N-nitroso-n-
methyluera", dated January 4,1990.
4 See US EPA, "Municipal Waste Combustion
Study: Combustion Control of Organic Emission",
EPA/530-SW.87-021C, NTIS Order No. PB87-
206090, US EPA, "Municipal Waste Combustion
Study: Flue Gas Cleaning Technology", EPA/530-
SW-87-021D, NTIS Order No. PB87-206108, and 54
FR 52251 (December 20,1989).
6 See discussions in US EPA, "Background
Information Document for the Development of
Regulations for PIC Emissions from Hazardous
Waste Incinerators", October 1989. (Draft Final
Report), and Engineering Sciences, "Background
Information Document for the Development of
Regulations to Control the Burning of Hazardous
Waste in Boilers and Industrial Furnaces, Volume
III: Risk Assessment", February 1987. (Available
from the National Technical Information Service,
Springfield, VA, Order No. PB87173845.)
8 We believe that virtually all sludge dryers meet
the tank definition and therefore would be exempt
when used as part of a wastewater treatme-
system.
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Federal Register / • Vol. 55, No. 82 / Friday,' April. 27, 199Q / Proposed Rules
17867
treatment unit are exempt from
regulation; and [2) sludge dryers that are '.
not exempt are subject to regulation
under part 265, subpart P,:or part 284,
subpart X, as thermal treatment unlts^ .
including those sludge dryers that meet
the current definition of an incinerator.
• Given that the Agency never intended to
regulate as incinerators sludge dryers "
that met the definition of incinerator
when it was revised in 1985, nonexempt
sludge dryers (those not meeting the
definition of wastewater treatment unit)
are subject to regulation under the
interim status standards of part 265,
subpart P, and the permit standards of
'part 264, subpart X, for other treatment
devices. Accordingly, EPA plans to
propose a revision to the incinerator
definition to explicitly exclude sludge
dryers.
To distinguish between sludge1 dryers
and incinerators, EPA plans to propose
the following definition: "sludge dryer"
means any enclosed thermal treatment
device used to dehydrate sludge and
that has a maximum thermal input (from
wastes and auxiliary fuel] of 1,500 Btu/
Ib of waste treated. EPA believes that
this definition would clearly distinguish
dryers from incinerators because
incinerators require much higher
thermal input—from 3,300 to more than
19;000 Btu/lb of waste treated—to
achieve the temperatures required to
destroy organic compounds to levels
required by the subpart O destruction
and removal efficiency standard. EPA
believes that, for sludge dryers, the
7 In selecting a risk thresh, of 10~8 for these rules,
EPA considered risk thresholds in the range of 10"*
to 10"'. As discussed in section I.D. of Part Three of
the text, the Agency requests comment on
alternative risk thresholds.
8 An MEI location is sometimes defined in terms
of current land use, i.e., as that location where
people are currently exposed to the highest ambient
pollutant concentrations. By this definition, MEI
thermal input is invariably less- than
1,500 Btu/lb. •':-••'•
IV. Need for Controls
A. Risks From Toxic Metals Emissions
:The Agency has determined that risks
from the burning of metal-bearing
hazardous wastes in incinerators can be
unacceptable under reasonable,, worst-
case circumstances, as defined by
concentrations, of metals in the
incinerated waste, incinerator capacity
or feed rate,, partitioning of metals to
bottom ash, collection efficiency of
emission control equipment, and local
terrain and meteorological conditions.
For purposes-of this rule, unreasonable
risks are considered to be either: (1)
exceedance of incremental lifetime
cancer risk of greater than 1X 10~B to the
potential maximum exposed individual
(MEI) T; or (2) exceedance at the MEI of
Reference Air Concentrations (RACs)
for noncarcinogens established as 25
percent of the Reference Dose (RfDs) '
(except that for lead, the RACis
established at 10 percent of the National
Ambient Air Quality Standard and1 for
HCI, the RAG is based directly on
inhalation exposurestudies). (See
discussion in part three below.)
For the purposes of-this regulation, the
Agency conservatively defines the
maximum exposed individual in terms
of potential exposure:, the MEI is
assumed to be located where ambient
pollutant concentrations created by a
facility are highest, even if this location
is not currently populated. Thus, the
concentrations may be Awertharnnaximum
observed concentrations. Since EPA's intention is to
be fully protective of health in the future as well as
the present, and since this analysis must generalize
on the basis of a sample of situations, we have
defined the MEI in'terms of maximum potential
exposure. We also note that the ground-level
, concentrations of interest are the off-site
concentrations except where people reside on site
potential MEL exposure predicitions are
more conservative than the actual MEI
concentrations.8
EPA has evaluated potential health
risks from metals emissions under
reasonable, worst-case scenarios.
Conservetiv-e dispersion coefficients and
ambient lev els of metals that pose
acceptable health risk (see section I of
part III) were used to estimate health
risk from a liquid injection incinerator
and a rotary kiln incinerator^ See table
1. Clearly, metals emissions can pose
significant health risk. For the liquid
injection incinerator analysis, we made
the following assumptions: (1) the waste
feed contained metals at the 50th
percentile level * according to our data
base; (2) al],metals in the feed are
emitted1 (i.e;,, emissions are not,
controlled, and no metals are removed
with the bottom ash)} and (3) 10 percent
of the chromium emitted is hexavalent
chromium.,For the rotary kiln
incinerator, we made the following
assumptions: (1) the waste feed
contained metals at the highest levels in
the data base; (2) 0 to, 5 percent of each
metal is removed with the bottom ash;
: (3) the incinerator is equipped with a
venturi scrubber (VS-20) to control
particulate emissions that has a metal
collection efficiency as shown in table
G—3 of the boiler/furnace supplemental
notice (54: ER 43761 (October 26,1989));:
and (4) 10; percent of the chorimum
emitted is Kiexavalent chromium.
such as military bases, colleges, and'universitfes.
Whether on site>or off site ground-level
concentrations.will be considered in demonstrating
conformance vrith,the proposed controls will be left
to the discretion of the permit writer based on
whether people acuf ally live on site; • -
8 The data base is inadequate to derive percentile
values. The values shown represent SO percent of
the highest levisls of metala in the data base.
TABLE 1.—METALS EMISSIONS, CAN POSE SIGNIFSCANT RISK
Metah
Carcinogens
Noncarcinogens
Barium ' ' ~ ' • .,.............<
Thallium .................. .„._............._
Liquid injection incinerator
Concentration
(ppm)
/ -
250.0
7.5
500.0
1,725.0
500.0.
4,000.0
7,000.0
2:0
500,0
500.0
MEI cancer
risk
IE 03;
4E 06
: - : 1E 03
3E 03'
•• ••••
Ambient cone/
RAC
••
2E-1-00
TE 01
1E+02
1E-03
2E-01
2E+00
i Rotary kiln incinerator
Concentration
(ppm). :
SCIO.O
15.0
1,000.0
3.4SO.Q
1,000.0
8,000.0
14,0(10.0
4.0
1,000.0
. 1,000.0
MEI cancer
risk-
4E 04
- 2E-08
3E 04
2E 05
.... ...........
Ambient cone/
RAG
......,».. >».............
• •-..-... ...
6E-01
1E-03
.3E+01
9E 04
' 4E-02
6E-01
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17666''
Fede
ster 7 Voir J
7 Proposed Rules
2?. Risks from Hydrogen Chloride
Emissions
EPA is today proposing to supplement
the existing technology-based HC1
standard with a standard based entirely
upon evaluation of health risk. The
existing HCl standard requires that an
incinerator control HCl emissions by 99
percent or emit only 4 Ib/hr (1.8 kg/hr).
The Agency has determined through
risk assessments of reasonable, worst-
case facilities that the short-term
reference air concentration (RAG] for
HCl can be exceeded under the existing
rule. Thus, EPA is proposing to regulate
HCl under the same risk-based
• standard-setting approach proposed for
metals. These standards will be in the
form of site-specific risk analysis
standards, with conservative screening
limits provided to ease the burden on
the applicant. For more information on
the proposed HCl standards, see Part
Three, Section HI: Proposed Controls for
Emissions of Hydrogen Chloride.
C, Potential Risks from Products of
Incomplete Combustion (PICsJ
The destruction and removal
efficiency (DRE) approach to control
organic emissions used hi the present
regulations has some inherent
limitation!!. It does not control the actual
mass of POHCs emitted since, for any
given DRE, the mass emissions vary
directly in proportion to variations hi
mass feed rate. More importantly, the
approach fails to account directly for
emissions of PICs, which can be as toxic
as, or more toxic than, the POHCs. .
As discussed in part Three of this
preamble, available data on PIC
emissions are limited. The studies done
thus far indicate that emissions of toxic
organic compounds from incinerators
could result in an increased lifetime
cancer risk of 10~'(i.e., 1 in 1,000,000) to
persons exposed to the maximum
annual average ground-level
concentration. The data base on PIC
emissions is limited, however, and thus
those risk assessments under-estimate
the risk. Those assessments consider
only the organic compounds that have
been actually identified and quantified.
Only 0 to 60 percent of total unburned
hydrocarbon emissions have been
chemically identified at any particular
facility. Thus, the bulk of the
hydrocarbon emissions have not been
considered in those risk assessments.
Although many of the unidentified,
unqualified organic compounds may be
nontoxic, some fraction of the organic
emissions is undoubtedly toxic.
Considering that the available data are
limited, EPA believes it is prudent to
require incinerators to operate at a high
combustion efficiency to minimize the
potential health risks from PIC
emissions.
PART TWO: REGULATORY OPTIONS
CONSIDERED
This part discusses the options
considered by the Agency when
developing the standards proposed
today.
I. Particulate Emission Limits
A. Consideration of Controlling Metals
with a Particulate Standard
The existing regulations control metal
and some organic emissions through the
performance standard for particulates.
Metals can be contained in particulates
or condense out onto particulates and
are then captured by air pollution
control devices. The present particulate '
standard of 180 milligrams per dry
standard cubic meter may not provide
adequate protection if a substantial
percentage of the particulate is
composed of toxic metals.10 Further, in
the case of volatile metals such as
arsenic, mercury, and chlorides of lead
and cadmium, the particulate standard
may provide little control.
Existing hazardous waste composition
data make it difficult to estimate the
average, or reasonable, worst-case
levels of toxic metals in wastes that are
incinerated. In addition, as the Agency
continues to prohibit land disposal of
untreated hazardous waste, hazardous
wastes with very high metals levels may
be incinerated hi the future. Also, testing
for metals levels in incinerator
emissions has been insufficient to
determine the average, or reasonable,
worst-case levels of metals emissions to
be expected from hazardous waste
incinerators. However, there is nothing
hi the present regulations that would
prohibit an incinerator operator from
introducing extremely high
concentrations of toxic metal-containing
wastes into an incinerator, thereby
creating a situation that-would present
high risks from toxic metals emissions.
Analysis of a hypothetical reasonable,
worst-case situation indicates that
present rules may not be adequate to
maintain low levels of risk from toxic
metals under all possible scenarios.
Even relatively low concentrations of
toxic metals in wastes can result in
unacceptable levels of risk if the wastes
are burned in incinerators without air
pollution control devices. Based upon
the 1981 mail survey,l l almost half of all
10 Mitre, op. cit., page 8.
11DPRA. 1981. Regulatory Impact Analysis Mail
Survey. Manhattan, Kansas.
interim status incinerators had no air
pollution control device because, as
liquid waste incinerators, they did not
emit enough particulate matter to
require an air pollution control device to
meet the particulate standard of 180 mg/
dscm.
It does not appear sufficient at this
time, in the Agency's judgment, to rely
solely on a particulate standard as a
surrogate for adequate control of toxic
metals. Given that there is virtually no
upper bound in the levels of metals in
hazardous wastes that may be
incinerated (absent regulatory control],
we have no assurance that the
particulate control provided by state-of-
the-art technology would be adequate in
all cases. Thus, we believe that the risk-
based standards proposed today are
preferable to a technology-based
particulate standard alone to control
metals.
B. Consideration of a More Stringent
Particulate Standard
EPA is not proposing to revise at this
time the existing standard of 0.08 gr/
dscf for the control of particulate matter
(see 40 CFR 264.343(c)). This standard
was based on the new source
performance standard (NSPS) developed
under the Clean Air Act in 1979 for solid
waste incinerators. On December 20,
1989, however, EPA proposed a
particulate emissions NSPS for
municipal waste combustors (MWCs] of
' 0.015 gr/dscf. See 54 FR 52251. This more
stringent standard takes advantage of
technology advances made in the field
of air pollution control.
The Agency has considered lowering
the hazardous waste incinerator
particulate standard of 0.08 gr/dscf to be
consistent with the proposed MWC
standard. However, reasonable, worst-
case dispersion analyses show that the
existing particulate standard of 0.08 gr/
dscf limits ambient levels generally to
less than 30 percent of the 24-hour
average PMio (particulate matter sized
less than 10 microns) National Ambient
Air Quality Standard (NAAQS), 150 fig/
m3. Further, we note that the existing
particulate standard would, under
today's rule, be supplemented with risk-
based standards to control emissions of
organic compounds and metals that may
be adsorbed on particulate matter. In
addition, where a problem with the
NAAQS is identified in a particular
area, the Agency or authorized State
should be* including all sources of
particulates hi the State Implementation
Plans (SIPs). Therefore, if an incinerator
creates or aggravates a problem with the
NAAQS, regulation of that source (with
respect to particulate emissions) would
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Federal Register / Vol. 55, No. 82 / Friday, April 27, 1990 / Proposed Rules
178.69."
be addressed under the SIP process or
potentially by a RCRA permit writer
usiiig the omnibus permitting authority.
In developing today's proposed rule, a
number of people representing a wide
range of interests (e.g., industry
representatives, environmentalists) have
indicated, however, that the rule may be
simpler to implement and more
protective if the controls were
technology-based. They advocate using
risk assessment only as a check to
determine if the standards are protective
on a site-specific basis. They cite the
current limitations of risk-based
standards in this particular-situation,
including: (1) indirect exposure (e.g.,
uptake through the food chain) has not
been considered for carcinogens; (2)
metals controls are proposed only for
those metals for which sufficient health
effects data exist to establish acceptable
ambient levels; and (3) the metals
controls are difficult to implement by '. -
limiting feed rates of individual metals
given the physical matrices of wastes
and the variability of metals
concentrations. We agree with these ..-
concerns and are initiating a testing
program to develop technology-based
controls for particulate matter to
provide a measure of control for
particulates, including metal particulates
and adsorbed organic compounds,
commensurate with best demonstrated
technology (BDT) for hazardous waste
incinerators. See RGRA section
3004(a)(l)—section 3004 standards are
to be revisedperiodically to take into
account improvements of measurement
and technology. If EPA establishes a
BDT particulate standard, the risk-based
controls for metals emissions would still
apply and would then be used as: a
-check to determine if the BDT standard
provides adequate protection on a case-
by-case basis. Given the limitations of
current risk assessment methodologies,
we do not believe that it could be
demonstrated that a BDT.standard
substantially over-regulates in many .'
situations.
We are not proposing at this time to
lower the existing particulate standard
because we have not conducted
adequate field testing of hazardous
waste incinerators to establish a BDT
particulate standard.12 Further, once the
tz we note that several States control hazardous
waste incinerator particulate emissions to levels
well below EPA's standard of 0.08 gr/dscf. In
addition, several hazardous waste incinerators have
been demonstrated to be capable of routinely
controlling particulate emissions to levels in the
0.01-0.02 gr/dscf range, or less. Further, as
discussed above in the text, the proposed
particulate standard for MWCs is 0.015 gr/dscf.
Thus, we anticipate that a BDT particulate standard
for hazardous waste incinerators would be within
that range of 0.01 to 0.02 gr/dscf. .-.'.''
BDT standard is identified, we would
then need to consider the impact on the
regulated community of applying the
standard to establish a reasonable
compliance schedule,
II. Definitions of incinerators and
Industrial Furnaces .
We discuss below the basis for
proposing to revise the definitions of
incinerator and industrial furnace, the
regulatory status for sludge dryers, and
a request for comment on regulating all
hasardous waste thermal treatment
devices under parts 264 arid 265, subpart
o. "..:•-.'. ' ; • - "
A. Definition of Incinerator and
Industrial Furnace
Existing definitions in § 260.10 for
incinerators and industrial furnaces
consider how thermal energy is
provided to the device. Both definitions
stipulate that the device must utilize
controlled flame combustion, thus
excluding devices using other means to
supply the heat necessary to combust or
otherwise themally treat waste. Thus,,
for example, electric arc smelters are
not industrial furnaces anddevices •
using infrared heat to destroy waste are
not incinerators. Significant regulatory
consequences result from these !
determinations. Electric arc smelters
that reclaim nonindigenous metal
hydroxide sludges are not industrial"
furnaces, and, thus, are exempt from T
regulation under § 261.6(c)(l), while
smelters using direct flame combustion
to reclaim the same sludge would be
regulated under the May 6,1987, -.
proposed rules for boilers and industrial
furnaces. Infrared devices used to
destroy waste would be regulated under
the subpart X permit standards of part
284 and.the subpart P interim status : :
standards of part 265, while controlled
flame incinerators would be regulated
under subpart O of parts 264 and 265
(and any amendments resulting from
today's proposal). The subpart X permit
standards under part 264 are not
prescriptive; permit writers use
engineering judgment and risk analysis
to determine appropriate permit
conditions.
We believe that incinerators and
industrial furnaces pose much the same
risk irrespective of whether they use
controlled flame combustion or some
other means to provide heat energy.-
Therefore, we are proposing to replace
or temper the reference to controlled
fiaine combustion in respective
definitions.
1. Revised definition of industrial
furnace. We are proposing to revise the
definition of industrial furnace to refer
to thermal treatment rather than, to
controlled flame combustion. We
believe that there are very few
additional indiistrial furnaces (that
process nonindigenous waste) that
would be regulated under this expanded
definition, and. it makes no sense to
regulate these few furnaces differently
: than other industrial furnaces
processing the same materials. EPA
specifically requests comments on the
need fo? the revised industrial furnace
definition and resulant impacts on the
regulated community.
2. Plasma arc and infrared devices
are incinertors. We are proposing to
revise the definition of incinerator to
include explicitly two noriflame
combustion devices: plasma arc and
infrared incinerators. Although these
devices are sometimes considered to be
nonflame devices rather than
incinerators, we believe that they should
be regulated as Subpart O incinerators
for two reasons. First they invariably
employ afterbiirners to combust
hydrocarbons driven off by the plasma
arc or infrared process. Thus, it can be
argued that these-units, in fact, meet the
current definition of an incinerator.
Second, we believe that the Subpart O
incineratorstandardscan.be
appropriately iapplied to 'these devices;
the technical requirements, of subpart O
are appropriate to address the hazards
posed by these devices. We also note
that applying the Subpart O standards
will reduce th« burden on both permit
writers and applicants. The Subpart X
standards are noriprescriptive standards
under which permit writers apply permit
conditions as appropriate to protect
human health and the environment. .
•-Thus, under sinbpart X, permit writers
would need to Determine on a case-by-
case basis whether particular provisions
of subpart O are appropriate and "
whether additional permit conditions
would be needed. Using Subpart O
standards renjoves the ambiguity for"
both permit winters and applicants over
what requirements are necessary.
Today's proposed amendments to the
incinerator standards likewise appear
suitable for plasma arc and infrared
incinerators. We request comment on
=. whether there are other "noriflame"
combustion devices for which the •
Subpart O incinerator standards are
applicable (i.e.;, devices that use an
afterburner to combust hydrocarbons
generated from hazardous waste by a
nonflame process).
We note that we are proposing only to
change (or clarify) the regulatory status
of these two classes of devices, not to •-.--..
subject them to'regulation for the first
time. Thus, interim status is not being
reopened for these devices. They have
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17870
Federal Register / Vol. 55, No. 82 /Friday, April 27. 1990 / Proposed Rules
been regulated since 1980 under subpart
P (Interim status standards for thermal
treatment units), subpart X {permit
standards for other treatment units), or
subpart O (interim status and permit
standards for incinerators). We note
that the interim status standards of part
205, subpart P. are virtually identical to
the interim status standards of part 265,
subpart O.
3. Fluidized bed devices are
incinerators. EPA would also like to
clarify that fluidized bed devices are
incinerators and are regulated under
subpart O. They are not subject to the
thermal treatment standards of part 265,
subpart P, or requirements established
under part 284, subpart X. Fluidized bed
incinerators are enclosed devices that
aro designed to provide contact between
a heated inert bed material fluidized
with air and the solid waste. Gas is
passed upwards through a column of
fine parUculates at a sufficient velocity
to cause the solids/gas mixture to
behave like a liquid. The bed is
preheated by overtired or underfired
auxiliary fuel. It is generally accepted
that fluidized beds meet the definition of
incinerator, although there may have
been some confusion in the past.
Although we are clarifying that they do
meet the definition of incincerator, we
specifically request comment on
whether there is sufficient ambiguity to
warrant adding fluidized bed devices to
the definition of incinerator.
4. Revised regulatory status of carbon
regeneration units. We are also
proposing to revise the regulatory status
of carbon regeneration units. Controlled
flame carbon regeneration units
currently meet the definition of
incinerator and have been subject to
regulation as such since 1980,l3 while
carbon regeneration nonflame units
have been treated as exempt
reclamation units. We are proposing to
regulate both direct flame and nonflame
carbon regeneration units as thermal
treatment units under the interim status
standards of part 285, subpart P, and the
permit standards of part 264, subpart X.
Our reason for doing this is that we are
concerned that emissions from these
devices may present a substantial
hazard to human health or the
environment We are not proposing to
" There iippeart to be confusion a* to the current
wtguletory status of direct flame activated carbon
regeneration unit*. Because EPA indicated in die
May 19,1630, preamble that all activated carbon
regeneration units wets engagod in a form of
meeting presently exempt from regulation [45 FR
33094), EPA is proposing In this notice to amend the
TCjjulffitloo* to control theia devices, both direct and
indirect flndL Consequently, the "in existence" date
for all activated carbon regeneration units would be
tin te of promulgation of final regulations.
apply the part 264, subpart O,
incinerator standards to these units
because we are concerned that
demonstration of conformance with the
DRE standards (and the proposed CO/
THC standards) may not be achievable
considering the relatively low levels of
toxic organic compounds absorbed onto
the activated carbon.
The prevailing view appears to be that
carbon regeneration units currently are
exempt recycling units. We have
considered whether or not these units
truly are engaged in reclamation, or
whether the regeneration of the carbon
is just the concluding aspect of the
waste treatment process that
commenced with the use of activated
carbon to absorb waste contaminants,
which are'now destroyed in the
"regeneration" process.14 Irrespective of
whether these units are better classified
as waste treatment or recycling units (or
whether the units are flame or nonflame
devices), we are concerned, as indicated
above, that emissions from the
regeneration process can pose a serious
hazard to public health if not properly
controlled. Consequently, nonflame
units in existence on the date of
promulgation (like flame units) would be
subject to part 265, subpart P, and new
units would be subject to part 264,
subpart X.
, We note that we intend for this
proposal to also apply to those carbon
regeneration units that meet the
definition of wastewater treatment units
in § 260.10 while they are in active
service. These units would not be
exempt from regulation when they are
being regenerated because they are no
longer treating wastewater. Rather, the
activated carbon columns themselves
are being treated thermally.
B. Regulation of All Thermal Treatment
Units Under Subpart O
The Agency has done some
preliminary thinking on an alternative
approach to regulating combustion
devices—the regulation of all thermal
treatment devices under virtually
identical standards under subpart O.
This would avoid a number of problems
with the current regulatory approach,
including: (1) Ambiguous definitions fpr
boilers and industrial furnaces; (2)
incomplete coverage of the incinerator
and industrial furnace definitions (e.g.,
14 We note that activated carbpn units used as air
emissions control devices frequently regenerate the
carbon in place by steam stripping, condensing the
organic contaminants for reuse. The trapped
organlcs in such columns are not hazardous wastes
because the gaa originally being treated is not a
solid waste (it is an uncontained gas), and therefore
any condensed organics do not derive from
treatment of a listed hazardous waste.
although today's proposal would expand
regulatory coverage of industrial
furances to include heating by means
other than controlled flame combustion,
furances other than those that are
"integral components of a
manufacturing process" (see § 260.10),
such as off-site facilities engaged solely
in waste management, could be engaged
in bonafide reclamation and should be
classified as an industrial furnace rather
than an incinerator); (3) the burden on
the regulated community and EPA and
State officials to process petitions to
classify individual devices as boilers or
industrial furnaces rather than
incinerators; and (4) the numerous
provisions in the proposed boiler and
furnace rules that would merely parrot
the current and proposed incinerator
standards.
Under this alternative approach, all
thermal treatment devices would be
regulated under the same risk-based
standards to control metals and HC1
emissions—the standards proposed
today for incinerators.18 Control of
organic emissions could also be the
same as those CO controls proposed
today for incinerators coupled with the
existing DRE standards for incinerators.
Devices handling wastes with low levels
of toxic organic constituents (e.g.,
smelters, sludge dryers, certain
incinerators), however, would not be
subject to organic emissions controls.
The applicability of standards could, in
many cases, be a function of waste
properties and composition. It may not
be necessary to identify applicability by
type of device,
EPA is continuing to consider this
alternative. In particular, we are
investigating whether the temporary
exclusion for the special wastes in
RCRA section 3001(b)(3) and the special
standards and exemptions proposed for
boilers and industrial furnaces can be
implemented without definitions for
these devices. We specifically request
comments on this alternative regulatory
approach whereby all thermal treatment
units could be regulated under one set of
standards under subpart O.
PART THREE: DISCUSSION OF PROPOSED
CONTROLS
I. Overview of EPA's Risk Assessment
In developing this regulation, the
Agency has used risk assessment to: (1)
determine that absent regulatory
15 We note that EPA is requesting comment on
applying these controls (as well as the proposed CO
controls) to boilers and industrial furnaces as well
in lieu of those proposed on May 6,1887. See the
Federal Register notice published today entitled,
"Burning of Hazardous Waste in Boilers and
Industrial Furnaces: Supplement to Proposed Rule."
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• • .-••'".' -.-..•••«• -•-i^; /••«^4 - •whw-'t £ft'.-,t?vi-'^e.'.i^v"V •'isJBigwli.rjapiSfibst-,. •
Federal Register /Vol. 55, No. 82 /Friday, April 27, 1990 /JPrqpcised Rules
liveir > :
.,'-17871
controls, emissions of products of
incomplete combustion, and certain
metals'can pose significant health
effects; (2) determine that the current
hydrogen chloride emissions standard
may not be fully protective in all
situations; and (3) establish risk-based,
conservative emission Screening Limits
for metals, hydrogen chloride (HC1), and,
under one alternative approach,
unburned hydrocarbons. The risk
assessment methodology is discussed in
detail in the background document '-.-
supporting this proposed rule—
Technical Background Document:
Controls for Metals and Hydrogen
Chloride Emissions for Hazardous
Waste Incinerators. The methodology is
summarized below for the convenience
of the reader.16 . _.;••
A. Overview of the Risk Assessment
Approach
, EPA's risk assessment approach
involves: (1) Establishing ambient levels
of pollutants (i.e., metals, hydrogen ;
chloride (HC1), and hydrocarbons (HC))
that pose acceptable health risk; and (2)
developing conservative dispersion
coefficients l7 for reasonable worst-case
facilities as a function of key parameters
(i.e., effective stack height,18 terrain
type, and land use classification). To
establish the conservative Screening
Limits for metals, HC1, and HC, we
back-calculated from the acceptable
ambient levels using the conservative
dispersion coefficients.
Under today's proposal, applicants
would be required to demonstrate that
emissions of metals, HC1, and (when
stack gas carbon monoxide
concentrations exceed 100 ppmv, and
under the health-based alternative
approach to assess HC emissions) HC
emissions do not result in an
18 We note that this discussion has been
presented virtually verbatim in the October 26,1989,
supplemenlalnotice to the May 1987 proposed
boiler and industrial furnace proposed rules. See 54 -
FR 43752 (Appendix F). We have, however, made
minor revisions to that discussion to: (1) explicitly
request.comment on alternative risk levels within
the range of W4 to W&, (2) better explain the
Agency's selection of a 10'B;aggregate risk threshold
for this rule; (3) explain that the Agency does not
intend for the methodology used to establish the
proposed reference air concentrations (RACs) to
imply a decision to supplant standards established
under the Clean Air Act; and (4) request comments
on whether the conservative assumptions'used in
the risk methodology properly balance the
nonconservative assumptions, or whether the
methodology creates RACs that are unnecessarily
stringent.
17 For purposes of this document, the term*
dispersion coefficient refers to the ambient
concentration that would result from an emission
rate of 1 gram/sec. This parameter is also
commonly called a dilution factor.
18 Effective stack height is the height above
ground level of a plume, based on summing the
physical stack height plus plume rise.
exceedance of the acceptable ambient
levels. If the conservative Screening
Limits are not exceeded, applicants
need not conduct site-specific dispersion
modeling to make this demonstration.
In developing the conservative
coefficients and acceptable ambient
levels for metals, Hd, and HC, EPA also
found that, under reasonable worst-case
situations, emission levels could pose
unacceptable risk absent regulatory
controls.
B.Identification of Reasonable Worst-
Case Incinerators by Terrain Type
1. Factors influencing ambient level's
of pollutants. Ambient levels of
pollutants resulting from stack
emissionsiare a function of the
dispersion of pollutants from the source
in question. Many factors influence the
.relationships between releases
(emissions) and ground-level
concentrations, including: (1) The rate of
emission; (2) the release specifications
of the facility (i.e., stack height, exit
velocity, exhaust temperature and inner
stack diameter, which together define '
the facility's "effective stack height"); (3)
local terrain; and (4) local meteorology -•
and (5) urban/rural classification.
2. Selection of Facilities and Sites for
Dispersion Modeling, Hazardous waste
incinerators are known to vary widely
in capacity, configuration, and design,
making it difficult to identify typical
parameters that affect dispersion of
emissions (i.e., release parameters). For
instance, stack heights of incinerators
listed in the 1981 survey 19 vary from
less than 15 feet to over 200 feet.
Furthermore, many new facilities that
are now in operation that are not listed
on the survey, and EPA expects that a
large number of additional facilities of
various types of designs are likely to be
constructed over the next several years. -..
For currently operating facilities, the
worst-case -dispersion situation would
be a combination of release
specifications, local terrain, urban/rural.
land use classification, and local
'meteorology that produces the highest
ambient concentrations of hazardous
pollutants per unit of pollutant released
by a facility. This can be expressed, for
any specific facility, as a dispersion .'_•
coefficient, which, for purposes of this
proposal, is the maximum annual
average (or, as explained later, for HC1,
maximum 3-minute) ground-level
concentration for an emission of 1 g/s (a
unit release); the units of the dispersion
coefficient are, therefore, /ig/m3/g/s.ao
Since dispersion co'efficients are, as a
general rule, inversely correlated with
effective stack heights, worst-case
facilities are most likely to be those with
the shortest effective stack heights. No
similar a priori judgment, however,
should be; made with respect to terrain
or meteorology; evaluation of the
influence of these factors requires
individual site-by-site dispersion
modeling. It was therefore Hot possible
to screen facility locations in advance to
select foe probable worst-ease situations
simply by considering stack height.
Instead!, out of a total number of 154
existing facilities"for which data were
available from the mail survey,21 we
roughly sorted the facilities into three
terrain types based on broad-scale
topograpjiic maps: flat, rolling, and
complex terrain. We then ranked the
facilities by effective stack heights.
Next, we evaluated terrain rise out to SO
km for each of the 24 facilities and
ranked the facilities by maximum
terrain rise. Finally, we subdivided the
24 facilities into three groups which are
loosely defined as flat, rolling, and
complex terrain. In addition, to enable
us to determine conservative dispersion
coefficients as a function of effective
height, we developed 11 hypothetical :
incinerators and modeled.each of these
"incinerators" at the 24 sites. The .
hypothetical facilities were selected fay .
.dividing Hie range of facilities listed in.
the 1981 Kurvey into 10 categories based
on effective stack height. Then, within
each stack height category, we selected
a hypothetical effective stack height that
approximated the 25th percentile of the
'. range of heights that existed within the
category. The 25th percentile was
chosen ini order to select a facility likely
to reflect the higher end of dispersion
coefficients (and ambient levels) in each
height-category. In addition, an eleventh
hypothetical source was defined in
order to represent facilities whose i . •'
heights of release do not meet good
engineering practice (see the discussion
on good engineering practice in Part
Three, II C, Site-Specific Risk Analysis
Standards). Such devices will
experience "building wake effects"—
turbulence created by adjacent : -..
structures that immediately mixes the
1SDPRA, op. cit. :
20 Dispersion coefficients can be defined for any
specific location surrounding a release. The
maximum dispersion coefficient will, under the
assumption;} used in this regulation, be the :
dispersion coefficient for the iilEI. Itmay occur at
any distance arid in any direction from the facility.
Howev.er, Ideations within the property boundary of
a facility wpuld not be considered when
implementing these proposed rules unless
individuals reside on site.
*' We nble that the survey should be
representative because it addressed'over 50 percent
of the 250 hazardous waste incinerators now in
operation.
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1.H72
Federal, Rej^gter /_VpL 55, No. 82 / Friday; April 27,r;199u /Proposed Rules
plume resulting in high ground-level
concentrations close to the stack.
Finally, we also included the site that
resulted in the worst-case complex
terrain conditions during development
0f the proposed rule for boOers and
industrial furnaces." Although there is
currently no hazardous waste
incinerator at that site, we used the site
as another theoretical location for the 11
hypothetical incinerators and merged
the results into those from the actual
incinerator sites. Under certain
conditions, this site provided higher
dispersion coefficients for some stacks.
In summary, 11 hypothetical
incinerators and the* actual incinerators
were modeled at each of 24 sites evenly
distributed among Hat, rolling, and
complex terrain. In addition, the 11
hypothetical incinerators were modeled
at an additional complex terrain site.
C. Development of Dispersion
Coefficients
Estimating the ah- impacts of the
facilities required the use of five
separate air dispersion models. We used
the EPA Guideline on Air Quality
Modek (Revised},*3 and consulted with
the EPA Office of Air Quality Planning
and Standards to select the most
appropriate model for each application.
For each of the 25 locations, five
consecutive years of concurrent surface
and twice-per-day upper air data (to
characterize mixing height) were ,
acquired. The data sets contained
hourly records of surface observations
for five years, or approximately 44,000
consecutive hours of meteorological
data. The same five-year data set was
used to estimate the highest hourly
dispersion coefficient during the five-
year period, and to estimate annual
average concentrations based on a five-
year data set for all release
specifications modeled at each location.
The actual incinerator release
specifications at each location were
used to select the appropriate model for
short-term and long-term averaging
periods. Once selected, the release
specifications for the actual incinerator
and the 11 hypothetical incinerators
wore modeled. Table 2 lists the models
selected.
TABLE 2.—MODELS SELECTED FOR THE
RISK ANALYSIS
" See "Background Information Document for the
Development of Regulations to Control the Burning
of lUutdoti* Waste In Coders and Industrial
Fonuet*, Volume HI: Risk Astcwmtnt",
Engtacedng-Setonces, February 1987. (Available
from the National Technical Information Sendee,
Springfield, VA, Order No. PB 87173845.)
«* USEPA. Guideline on Air Quality Models
(HetrfMd}, U.S. Environmental Protection Agency,
Olftca of Air Quality Planning and Standards,
RMKMcb Triangle Park, N.C. EPA-WO/2/78-OZ7R.
July IBtiO,
Terrain
classifica-
tion
Flat or
Roiling.
Flat or
Rolling.
Complex..-..
Complex...:..
Complex —
Urban/
Rural
Urban or
Rural.
Urban or
Rural.
Urban i
Urban
RuraJ «.«.«»..
Averaging
period
Annual
average.
Hourly
Annual
average.
Hourly -..
Hourly or
annual.
Model
selected
ISCLT
ISCST
LONG2
SHORTZ
COMPLEX
1
The Industrial Source Complex
models [ISCLT and ISCST) were
selected for flat and rolling terrain
because they can address building
downwash or elevated releases and can
account for terrain differences between
sources and receptors. The long-term
mode (ISCLT) was used for annual
averages, while the short-term mode
(ISCST) was used to estimate maximum
hourly concentrations.
To meet the EPA guidance on model
selection, we used three different
models to characterize dispersion over
complex terrain. For urban applications,
OAQPS recommends SHORTZ for
short-term averaging periods and
LONGZ for seasonal or annual
averages. For rural sites located in
complex terrain, OAQPS recommends'
the COMPLEX I model.
We used U.S. Geological Survey 7.5-
minute topographic maps to document
terrain rise out to 5 km from each stack.
For purposes of this proposed rule, a
facility is considered to be in flat terrain
if the maximum terrain rise within 5 km
of the stack is not greater than 10
percent of the physical stack height. The
facility is in rolling terrain if terrain rise
is greater than 10 percent but not greater
than the physical stack height, and in
complex terrain if terrain rise is greater
than the physical stack height.24
We also used the topographic maps as
the basis to classify land use as urban or
rural. A simplified version of the Auer
technique 2B based on the preferred land
24 We note that EPA can consider terrain well
past 5 km of a stack to define terrain type for some
facilities. We believe, however, that a radius of 5
km is adequate because we are concerned with MEI
exposures (as opposed to aggregate population
exposures) and because the effective stack heights
of concern are relatively low in comparison to
facilities such as major power plants. Thus, MEI
exposures for the conditions modeled will always
occur within 5 km of the stack.
35 Auer, August, H., Jr. Correlation of Land Use
and Cover with Meteorological Anomalies. Journal
of Applied Meteorology, Vol. 17, pp. 836-643, May
1978.
use approach (rather than population
density) was used for this classification.
If greater than 50 percent of the land
'was classified as urban, the models
were executed in the urban mode for
that facility. If greater than 50 percent
- was classified as rural, the rural modes
were used.26
To identify conservative dispersion
coefficients as a function of effective
stack height, we graphically plotted for
each terrain type (i.e., flat, rolling, and
complex) and each land use
classification (i.e., urban and rural)
dispersion coefficients for the modeled
facilities and locations as a function of
effective stack height. The outer
envelope representing the highest
dispersion coefficients was drawn to
enable us to identify conservative
coefficients for any effective stack
height within the range of those modeled
(i.e., 4 m to 120 m).
We determined that there was no
significant difference in dispersion
coefficients (under the severe conditions
modeled) between flat and rolling
terrain. Thus, those terrain types were
merged together and termed
noncomplex terrain* In addition, a
discontinuity was observed between the
SHORTZ/LONGZ and Complex 127
models, which resulted in our not
distinguishing between land use
classifications in complex terrain.
Finally, we note that mere was no
significant difference in 3-minute
exposures between urban and rural land
use in either noncomplex or complex
terrain. Thus, we have not distinguished
between land use classifications in
establishing the HCl Screening Limits,
There is, however, a significant
difference in maximum annual average
dispersion coefficients between urban
and rural land use in noncomplex
terrain, and so we have established
separate metals and THC Screening
Limits for those situations.
We note that the dispersion
coefficients used to establish the
Screening Limits are designed to be
conservative, but may, in fact, not be
conservative in extremely poor
dispersion conditions, or when the
receptor (location (i.e., residence)) is
28 OAQPS guidelines indicate that 50 percent is
the cutoff point between urban and rural; however,
to be conservative and to account for differences in
the accuracy of different measurement methods,
EPA is recommending that for permitting purposes
land use be considered urban if greater than 75
percent is urban; that it be considered rural if land
use is greater than 75 percent rural; and that if the
land use is between 75 percent urban and 75 percent
rural the more conservative Screening Limit of the
two be used.
27 Complex I was found to produce relatively low
estimates of short-term concentrations.
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Federal Register / Vol. 55, No, 82 / Friday, April 27, 1990 / Proposed Rules
17873
close-in to the source. Under the
situations identified below, the
Screening Limits may not be protective
and the permit writer should jequire.
site^specific dispersion modeling
consistent with EPA's Guideline on Air
Quality Models (Revised) to
demonstrate that emissions do not pose
unacceptable health risk:
• Facility is located in a narrow
valley less than I km wide; or
•• Facility has a stack taller than 20 m
and is located such that the terrain rises
to the stack height within 1 km of the
facility; or
8 Facility has a stack taller than 20 m
and is located within 5 km of the. •
shoreline of a large body of water (such
as an ocean or large lake); or
• The facility property line is within
200 m of the stack and the physical
stack height is less than lO^n; or
* On-site receptors are of concern,
and the stack height is less than 10 m.
In addition to the situations identified
above, there is a probability, albeit
small, that the combination of critical
parameters, stack height, stack gas
velocity, effluent temperature,
meteorological conditions, etc., will
result in higher ambient concentrations
than resulted from the conservative
modeling done to support this rule. As a
result, the Agency is reserving the right
to require that the owner or operator
submit, as part of the permit proceeding,
en air quality dispersion analysis
consistent with EPA's Guideline on Air
Quality Models (Revised) in order to
ensure that acceptable ambient levels of
pollutants are not exceeded irrespective
of whether the facility meets the specific
Screening Limits that would be
established by this regulation. ;
Finally, we specifically request
comment on whether less conservative
assumptions, coupled with a safety
factor then applied to assure that
ambient levels are not underestimated,
should be used to develop the Screening
Limits. This alternative approach may
have merit because the repeated use of ,
conservative assumptions in an analysis
may "multiply" the conservatism
unreasonably. Comments are solicited
on: (1) the extent to which less
conservative assumptions would enable
applicants to meet the Limits; (2) how to
reduce the conservatism of the
Screening Limits while still ensuring that
they are protective; and (3) how the
reduced conservatism would affect the
criteria discussed above that must be
considered to determine if the Screening
Limits are protective for a particular
situation. Note that, in section I.D. of
Part Three of the preamble, the Agency
requests comment on basing the
standards on alternative risk thresholds.
D. Evaluation of Health Risk -, :
1. Risk from Carcinogens. EPA cancer
risk policy suggests that any level of '
human exposure to a carcinogenic
substance entails some finite'level of
risk. Determining the risk associated
with a particular dose-requires knowing
the slope of the modeled dose-response
curve. On this basis, EPA's Carcinogen
Assessment Group (GAG) has estimated
carcinogenic slope factors for humans
exposed to known and suspected human
carcinogens. Slope factors are estimated
by a modeling process. The slope of the
dose-response curve enables estimation
of a unit risk. The unit risk is defined as
the incremental lifetime risk estimated
to result from exposure of an individual
for a 70-3rear lifetime to a carcinogen in
air containing 1 microgram of the
compound per cubic meter of air. Both -"'
the slope factors and unit risks are
reviewed by the Agency's Cancer Risk
Assessment Validation Endeavor ;
(CRAVE) workgroup for verification."
The unit risk values that the Agency is
proposing to use for today's incinerator-
amendments are identical to those the
Agency proposed for boilers and
industrial furnaces burning hazardous
waste. The unit risk values are
presented in Appendix J of the October :
26,1989 Supplement to Proposed Rule
for boilers/furnaces. See 54 FR 43763.
(We note mat the unit risk for beryllium
presented in Appendix J should be 2.4E-
03 ms/ug.) The acceptable ambient level
for a carcinogenic compound is termed
the risk-specific dose (RSD) and is
derived by dividing the acceptable
health risk by the unit risk value. As
discussed below, the risk threshold .
proposed for this rule is 10~5.28 Thus,
the RSDS for the metals that would be
regulated by today's rules can be
calculated by dividing 1X10"5 by the
unit risk values for the metals presented
in appendix J of the boiler/furnace
supplemental notice.29 The RSDs for the
a8 In selecting a 10~8risk threshold for these
rules, EPA considered risk thresholds in the range of
l
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17074
Federal Register / Vol. 55, No. 82 /Friday, April 27, 1990 / Proposed Rules
To implement this carcinogenic risk
assessment approach, we are proposing
tc limit the aggregate risk to the MEI to
10"*. This would limit the risk from
ir.tJm'dual carcinogenic metals to levels
o:s the order of 10~6 but below 10~s. In
selecting a 10" * aggregate risk threshold
level for this rule, we considered risk
thresholds in the range of 10"4 to 10~8,
the range the Agency generally uses for
various aspects of its hazardous waste
programs.
We considered limiting the aggregate
risk to the MEI to 10"« but determined
that this risk threshold would be
unnecessarily conservative for the
purpose of this rule". In reaching this
determination, we considered that, at an
aggregate risk level of 10~s, the risk level
for individual metals would be on the
order of 10~7, which we believe is overly
conservative for this rule.
Alternatively, we considered limiting
the aggregate risk to the MEI to 10~*. An
aggregate risk threshold of 10~4 would
result in limiting the risk level for
individual carcinogens on the order of
10"*. We did not select a 10"* aggregate
risk threshold for this proposed rule
because the risk assessment
methodology used to establish emission
limits considers only direct exposure to
tho metals via inhalation of dispersed
emissions. Other routes of exposure are
not accounted for by this methodology,
which means risks could be somewhat
higher. The Agency requests comments
on the magnitude and nature of these
risks.
As noted above, the Agency has
proposed that an aggregate risk level of
10" * is appropriate in today's regulation
because it would limit the risk level for
individual carcinogens to the order of
10"*. The Agency points out, however,
that hi selecting the appropriate risk
level for a particular regulatory program,
it considers such factors as the
particular statutory mandate involved,
nature of the pollutants, control
alternatives, fate and transport of the
pollutant in different media, and
potential human exposure. These same
factors can also influence choice of a
risk level where the Agency is making
si'.e specific determinations.
The Agency would like to use the
waight-of-avklence approach in
developing the health-based alternative
approach to assess hydrocarbon (HC)
tidlsstons under the Tier n PIC
controls.81 However, there are a number
*• We not* that the Mowing discussion in the
ItM pertain* only to lha lie»!th-btsed alternative for
limiting THC whan GO exoseds 3QO ppmv. Although
vn» tsqwett comment on the htalth-bseed approach.
K.-J prclcr Ibt tecfaology-bsscd approach of limiting
Tl iC to * good otwtttlns practice-Used level of 20
of unidentified compounds in the mix of
hydrocarbon emissions. These
unidentified compounds could be either
carcinogens or noncarcinogens, or both.
Of the compounds that may be
carcinogens, the Agency does not know
whether they would be classified as A,
* Bl, B2, or G carcinogens. Since the
Agency cannot classify these unknown
carcinogens, the Agency is unable to use
a weight-of-evidence approach to select
an acceptable risk level for HC. In order
to be conservative, the Agency is
assuming that HC can be treated as a
single compound for which a unit cancer
risk is calculated. To derive this unit
cancer risk value, the historical data
base of HC emissions from hazardous
waste incinerators, boilers, and
industrial furnaces was used. For each
organic compound identified in the
emissions, the 95th percentile
concentration value was taken as a
reasonable worst-case value. (The
highest concentration was often used
because there were too few data to
identify the 95th percentile value.) For
organic compounds listed in appendix
Vin of part 261 for which health effects
data are adequate to establish an RSD
or RAG, but which have not been
detected in emissions from hazardous
waste combustion, an arbitrary emission
concentration of 0.1 ng/L was assumed.
The data base was further adjusted to
increase the conservatism of the
calculated HC unit risk value by
assuming that the carcinogen
formaldehyde is emitted from hazardous
waste combustion devices at the 95th
percentile levels found to be emitted
from municipal waste combustors. The
proportion of the emission concentration
of each compound to the total emission
concentration for all compounds was
then determined. This proportion,
termed a proportional emission
concentration, was then multiplied by
the unit cancer risk developed by GAG
to obtain a risk level for that compound.
A unit risk of zero was used for
noncarcinogens like methane. All the
cancer risks were added together to
derive a weighted average 95th
percentile unit risk value for HC. This
procedure for developing a HC unit risk
value assumes that the proportion of the
various hydrocarbons is the same for all
incinerators. In addition, it weighs all
carcinogens the same regardless of
current EPA classification.
As explained in section IV of part HI
of the preamble, we are proposing to
limit'hydrocarbon emissions—when
stack gas carbon monoxide levels
exceed 100 ppmv, and under the health-
based alternative—based on a 10~s
aggregate risk level.8* Thus, we are
limiting each of the constituents to a rip1'
level on the order of 1Q~6.
Finally, in assessing the risk from
facilities that emit both HC and
carcinogenic metals, we are not
proposing that the 'risk from HC
emissions be added to the aggregate
MEI risk from metals emissions. Adding
the risk would be inappropriate because
we do not know how all the HC would
be classified according to weight of
evidence. (We note again that we prefer
the technology-based approach to limit
HC emissions for reasons discussed in
section IV of part III of the preamble.]
We specifically request comment on
this proposed approach to assess
carcinogenic risk. We also welcome
suggestions or alternative ways to
account for additivjty.
The Agency also requests comment on
whether aggregate population risk or
cancer incidence (i.e., cancer incidents
per year) should also be considered in
developing the national emission limits
and in site-specific risk assessments.
This approach could, in some situations,
be more conservative than considering
only MEI risk because, even if the
"acceptable" MEI risk level were not
exceeded, large population centers may
be exposed to emissions such that the
increased cancer incidence could be
significant. However, it would be
difficult to develop acceptable aggregate
cancer incidence rates. Nevertheless, it
is likely that many facilities that perform
a site-specific MEI exposure and risk
analysis would also generate an
aggregate population exposure and risk
analysis that could be considered by the
Agency. Based on public comment and
further thought on how to implement
this dual approach, the final rule could
incorporate consideration of both the
MEI and aggregate population risk.
Alternatively, EPA could provide
guidance to the permit writer on when
and how to consider cancer incidence
on a case-by-case basis under authority
of section 3005(c)(3) of HSWA, as
codified at § 270.32{b)(2).
2. Risk from Noncarcinogens. For
toxic substances not known to display
carcinogenic properties, there appears to
be an identifiable exposure threshold
below which adverse health effects
usually do not occur. Noncarcinogenic
effects are manifested when these
ppmv. See discussion ia section IV of part Three of
the text.
82 In selecting a risk threshold of 10"B for these
rules, EPA considered risk thresholds in the range of
1
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Federal Register / Vol. 55, No. 82 / Friday, April 27, 1990 /Proposed Rules
17875
pollutants are present in concentrations
great enough to overcome the
horrieostatic, compensating, and
adaptive mechanisms of the organism.
Thus, protection against the adverse
healtbTeffects of a toxicant is likely to be
achieved by preventing total exposure
levels from exceeding the threshold
dose. Since other sources in addition to
the controlled source may contribute to
exposure, ambient concentrations
associated with the controlled source
should ideally take other potential
sources into account. The Agency has
therefore conservatively defined
reference air concentrations (RACs) for
noncarcinogenic compounds that are
defined in terms of a fixed fraction of
the estimated threshold concentration.
The RACs for lead and hydrogen
chloride, however, were established
differently, as discussed below. The
RACs are identical to those the Agency
has proposed for boilers and industrial
furnaces burning hazardous waste. See
appendix H of the Supplement to
Proposed Rule at 54 FR 43762 (October
28,1989).33 (The Agency notes that it
does not intend for RACs to be used as
alneans of setting air quality standards
in other contexts. For instance, the RAG
methodology does not imply a decision
to supplant standards established under
the Glean Air Act.)
RACs have been derived from oral
reference doses (RfDs) for those
noncarcinogenic compounds listed in
, Appendix VKI of 40 CFR part 261
(except for lead and hydrogen chloride)
for which the Agency considers that it
has adequate health effects data. An-
oral RED is an estimate (with an "--
uncertainty of perhaps an order of
magnitude) of a daily exposure (via
ingestion) for the human population •
(including sensitive subgroups) that is
likely to be without an appreciable risk
of deleterious effects even if exposure
occurs daily for a lifetime. Since these
oral-based RACs are subject to change,
EPA contemplates publishing Federal
Register notices if the RACs change in a
way that affects the regulatory standard
(see also the discussion of this issue in
the Boiler/Furnace supplemental notice
published on October 26,1989 at 54 FR
43718.)
The Agency is proposing RACs
derived from, oral RfDs because it :
believes that the development of the
RfDs has been technically sound and
adequately reviewed. Specifically:
1. EPA has developed verified RfDs and is
committed to establishing RfDs for all
constituents of Agency interest. The
verification process is conducted by an EPA
workgroup, and the conclusions and reasons
for these decisions are publicly available.
2. The verification process ensures that the
critical study is of appropriate length and
quality to derive a health limit for long-term,
lifetime protection. /
• 3. RfDs are based on the best available
information meeting minimum scientific
criteria. Information may come from
experimental animal studies or from human
studies.
4. RfDs are designed to give long-term
protection for even the most sensitive
members of the population, such as pregnant
women, children, and older men and women.
5. RfDs are designated by the Agency as
being of high, medium, or low confidence
depending on the quality of the inf ormation
on which they are based and the amount of
supporting data. The criteria for the
confidence rating'are discussed in the RfD
• decision documents.
The Agency used the following
strategy to derive the inhalation
exposure limits proposed today:
.1. Where a verified oral RfD has been
based on an inhalation study, we will
calculate the inhalation exposure limit
directly from the study. : .
2. Where a verified oral RfD has been
based on an oral study, we will use a
conversion factor of 1 for route-to-route
extrapolation in deriving an inhalation limit.
- • 8. Where appropriate EPA health
documents exist, such as the Health Effects
Assessments (HEAs) and the Health Effects
and Environmental Profiles (HEEPs),
containing relevant inhalation toxicity data,
their data will be used in deriving inhalation
exposure limits. We will also consider other
; agency health documents (such as NIOSH's
criteria documents). •
4. If RfDs or other toxicity data from
agency health documents are not available,
then we will consider other sources of
toxicity information. Calculations will be .
made in accordance with the RfD
methodology.
The Agency recognizes the limitations
of route-to-route conversions used to
derive the RACs and is in the process of
examining confounding factors affecting
the conversion, such as: (a) the
appropriateness of extrapolating when a
portal of entry is the critical target
organ; (b) fest pass'effects; and (c)
effect of route on dosimetry.
The Agency, through its Inhalation
RfD Workgroup, is developing reference
dose values for inhalation exposure, and
some are eixpected to be available this
year. The Agency will use the available
inhalation RfDs—after providing
appropriate opportunity for public
comment—when this rule is •
promulgated. Certainly,'if the workgroup
develops inhalation reference doses ."
prior to promulgation of today's rule that:
are substantially different from the
RACs proposed today, and if the revised
inhalation reference dose could be
expected to have a significant adverse
impact on the regulated community, the
Agency will take public comment on the
revised RACs after notice in the Federal
Register. "" • - -.--•-. , -..-;•• .
EPA proposed this same approach for
deriving RACs on May 8,1987 (52 FR
16993) for boilers and industrial furnaces
;burning hazardous waste. We received a
numberiof'Comments on the proposed
approach of deriving reference air
concentrations (RACs) from oral RfDs.
As stated :in today's proposal and the
May 6,1987, proposal, we would prefer
to use inhalation reference doses. Some
comments suggested other means of
deriving RACs. We will consider those
comments and others thatmay be
submitted as a result to today's proposal
hi developing the final rule.
As previously stated, EPA has derived
the RACs from oral reference doses
(RfDs) for the compounds of concern. An
oral RfD isi an estimate of a daily
exposure ('via ingestion) for the human
population that is likely to be without an
appreciable risk of deleterious effects,'
even if exposuie occurs ctaily throughout
a lifetime.:34 The RfD for a specific -
chemical is calculated by dividing the
experimentally determined no-observed-
adverse-effect-level (NOAEL) or lowest-
observable-adverse-effect-leyel
(LOAEL) by the appropriate uncertainty
factor(s). The RAG values inherently
take into account sensitive populations.
The Ageincy is proposing to use the
following equation to convert oral RfDs
to RACs: -
RAG [mg/m3)
RfD (mg/kg-bw/day) X body weight X correction factor X background level factor
m3 air breathed/day , , ; ; -.".-
-- 33 rjote that the RAG for HC1 presented in
Appendix I of the Boiler/Furnace supplemental
notice is incorrect The long-term (i.e., annual)
exposure RAG should be 7 ;tg/m3, and the 3-minute
exposure RAG should be 150 jig/ms.
84 Current scientific understanding, however,
does not consider this demarcation to be rigid. For
brief periods aiid for small excursions above the
RfD, adverse effects are unlikely in most of the
population. On the other hand, several
circumstances can be cited in which particularly
sensitive members of the population suffer adverse
responses at levels well below the RfD. See 51 FR
1627 Oanuary 14,1986).
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37876
where:
* RID is the oral reference dose
• Body weight (bw) ts assumed to be 70 kg
for an adult male
" Volume of air breathed by an adult male
is assumed to bs 20 m'per day
• Correction factor for route-to-route
extrapolation (going from the oral route
to the inhalation route) is 1.0
» Background level factor is 0.25. It is a
factor to fraction the RID to the intake
resulting from direct inhalation of the
compound emitted from the source (i.e.,
an individual is assumed to be exposed
to 75 percent of the RfD from the
combination of indirect exposure from
the .source in question and other
sources).
a. Short-term exposures. In today's
proposed rule, the RACs are used to
determine if adverse health effects axe
likely to result from exposure to stack
emissions by comparing maximum
annual average ground-level
concentrations of a pollutant to the
pollutant's RAG. If the RAG is not
exceeded, EPA does not anticipate
adverse health effects. The Agency,
however, is also concerned about the
impacts of short-term [less than 24-hour)
exposures. The ground-level
concentration of an emitted pollutant
can be an order of magnitude greater
during a 3-minute or 15-muiute period of
exposure than the maximum annual
average exposure. This is because
meteorological factors vary over the
course of a year resulting in a wide
distribution of exposures. Thus,
maximum annual average
concentrations are always much lower
than short-term exposure
concentrations. On the other hand, the
short-term exposure RAG is also
generally much higher than the lifetime
exposure RAG. Nonetheless, in some
cases, short-term exposure may pose a
greater health threat than annual
exposure. Unfortunately, the use of RfDs
limits the development of short-term
acute exposure limits because no
acceptable methodology exists for the
derivation of less than lifetime exposure
from the RfDs.86 However, despite these
limitations, the Agency is proposing a
short-term 0.e., 3-minute) RAG for HC1
of 160 /ig/ms, based on limited data
documenting a no-observed-effect-level
in animals exposed to HCl via
Inhalation.*6 We do anticipate,
'* Memo from Clara Chow through Reva
Rub«n»tein, Characterfuttaii and Assessment
OlvMon. EPA. to Robert HoUoway. Waste
Management Division, EPA, entitled "Use of RfDs
VWIUM TLV» for Bwlth Criteria," January 13,1987.
*• Mean fen UML Rateltff, Churactarfxatfon and
A»»««nant Mvto lea ta Ihrlght HttiUck. Waste
Muiisemcnt Division. October 2,1988, ioterprettag
rcsutii from Scltakumar, AJR.S Snyder, CA.;
Solomon, J,j4 Albert, R.E, (1985) Carcinogenldtyof
however, that short-term RACs for other
compounds will be developed by the
Agency in the future.
b. RAG for HCl. The RAG for annual
exposure to HCl is 7 /ig/m3 S7 and is
based on the threshold of its priority
effects. Background levels were
considered to be insignificant given that
there are not many large sources of HCl
and that this pollutant generally should
not be transported over long distances
in the lower atmosphere. The RAG for 3-
minute exposure is 150 jjig/m3.38 As
noted above, EPA also proposed these
RACs for HCl in the boiler and furnace
proposed rule. See 54 FR 43718 (October
26,1989). The Agency requests comment
on whether the conservative
assumptions used in its methodology
properly balance the nonconservative
assumptions, or whether the
methodology creates RACs that are
unnecessarily stringent.
c. RAC for Lead. To consider the
health effects from lead emissions, we
adjusted the National Ambient Air
Quality~Standard (NAAQS) by a factor
of one-tenth to account for background
ambient levels and indirect exposure
from the source in question. Thus,
although the lead NAAQS is 1.5 ju.g/m3,
for purposes of this regulation, sources
could contribute only up to 0.15 ftg/m3.
Given, however, that the lead NAAQS is
based on a quarterly average, however,
the equivalent annual exposure is 0.09
p,g/m3for a quarterly average of 0.15
p,g/m3. Thus, the lead RAC is 0.09 ftg/
m3. EPA has also proposed this RAC in
the boiler and furnace proposed rule.
See 52 FR17006.
d. Relationship to NAAQS. The Clean
Air Act (CAA) requires EPA to establish
ambient standards for pollutants
determined to be injurious to public
health or welfare. Primary National
Ambient Air Quality Standards
(NAAQS) must reflect the level of
attainment necessary to protect public
health allowing for an adequate margin
of safety. Secondary NAAQS must be
designed to protect public welfare in
addition to public health, and, thus, are
more stringent.
As discussed above, the Reference Air
Concentration (RAC) proposed today for
Lead is based on the Lead NAAQS. As
the Agency develops additional NAAQS
for toxic compounds that may be
Formaldehyde and Hydrogen Chloride in Rats.
Toxicol. Appl. Pharm. 81:401-406.
57 Memo dated May 4,1989, from Mike Dourson,
EPA Office of Health and Environmental
Assessment, to the RfD Workgroup, entitled RfD
Meeting of February 18,1889.
' 3S Memo from Lisa Ratcliff, EPA, to Dwight
Hlustick, EPA, entitled "Short-term Health-based
Number for Hydrogen Chloride," September 15,
1988. ' '•:
emitted from hazardous waste
incinerators, we will consider whether'
the acceptable ambient levels (and,
subsequently, the feed rate and emission
rate Screening Limits) ultimately
established under this rule should be
revised.
The reference air concentration values
(and risk-specific dose values for
carcinogens) proposed here in no way
preclude the Agency from establishing
NAAQS as appropriate for these
compounds under authority of the CAA.
E. Risk Assessment Assumptions
We have used a number of
assumptions in the risk assessment,
some conservative and others
nonconservative, to simplify the
analysis or to address issues where
definitive data do not exist.
Conservative assumptions include the
following:
• Individuals reside at the point of
maximum annual average and (for HCl)
maximum short-term ground-level
concentrations. Furthermore, risk estimates
for carcinogens assume that the maximum
exposed individual resides at the point of
maximum annual average concentration for a
70-year lifetime.
• Indoor air contains the same levels of
pollutants contributed by the source as
outdoor air.
• For nonoarcinogenic health
determinations, background exposure
already amounts to 75 percent of the RfD.
Tills includes other routes of exposure,
including ingestion and dermal. Thus, the
incinerator is only allowed to contribute 25
percent of the RfD via direct inhalation. The
only exception is for lead, where an
incinerator is only allowed to contribute 10
percent of the NAAQS. This is because
ambient lead levels hi urban areas already
represent a substantial portion (e.g., one-third
or more) of the lead NAAQS. In addition, the
Agency is particularly concerned about
health risks from lead in light of health
effects data available since the lead NAAQS
was established. EPA is currently reviewing
the lead NAAQS to determine if it should be
lowered.39
3B At this point, we have not attempted to
quantify indirect exposure through the food chain,
Jngestion of water contaminated by deposition, and
dermal exposure, because ais yet no acceptable
methodology for doing so has been developed and
approved by the Agency for use for evaluating
combustion sources. We note, however, that by
allowing the source to contribute only 25 percent oi
the RfD (or 10 percent of the NAAQS in the case of
lead) accounts for indirect exposure by assuming a
person is exposed to 75 percent of the RfD from
other sources and other exposure pathways. (EPA
has developed such a methodology for application
to waste combustion sources. The Agency's Science
Advisory board has reviewed this methodology, and_
the Agency is continuing to refine the methodology.
When the Agency completes development of
procedures to evaluate indirect exposure, a more
detailed analysis may be applied to incinerators
burning hazardous wastes.)
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Federal Eegjatar /
No.
April 27, 1990 / grajMtged Rules
• Risks, are considered, for pollutants that
are knowiu probable,, and possible human
carcinogens;
• Individual health risk numbers have
large uncertaiHQF faelorsi implicit ra ttieflr
derivation to take into effect the mast •
sensitive portion of the population.
Nbneonservative assumptions include
the following:: .'."•-
• Although emfssfon are complex mixtures,
interactive effects ol threshold or
carcinogenic compoanda haves not been
considered in this regulation because data on
such relationships are inadequate;.*0
• Environmental effects (te., effects on
plants, and animals} have not been
considered because ofa fade of adequate
information. Adverse effects1 on plants'and
animals may occur at levels lower fhaa those
that cause adverse human health effects.
{Tha Agency fa also- developing procedures:
and requesting^ Science Advisory Board;
re view to consider environmental effects
resulting from emissions from all categories
of waste combustion facilities1.]"
F. Risk Assessment Guideline
EPA proposes to implement the: risk-,
based controls for metals, HCIt and
(under the feealthAased altematiwej
THC emissions using procedures and
information presented in'today's
preamble, The procedures and
information would be provided to permit
writers, in a document that would be
entitled Risk Assessment. Guideline for
Permitting Hazardous Waste Theimai
Treatment Devices [RAG}., The RAG
would be incorporated by reference in
the rules at § 270,8.' Although, the
document has not y/ei faeea written, it
would include information presented in
today's notice such ast (1J: RACs and
RSDs for pollutants, of concern {i.e.. '
. metals* HCI. and THCs}; (2J Screening
Limits for metals, HO, and THCs; and
(3) procedures for reviewing site-specific
dispersion modeling plans and results
submitted by applicants. The RAG
would be published concurrently with.
final promulgation of the amendments
proposed today.
In. lieu of providing this information in
a guidance document, we are
considering codifying it as part of the
regulation. Our concern is that guidance
documents da not cany the weight of a
•regulation—permit writers would be free
to accept, or reject the guidance (e.g..
Screening Limits, RACs. RSDa) and
would be obligated to. justify use and
appropriateness, of the guidance prt a
case-by-ease basis. This could place a
substantial burden on the permit writer
and result in inconsistent and,. perhapSj
inappropriate permit conditions. We
specifically, request comment ojtt
Whether the Screening Limits, RACs,' '
and RSDs should he codified!
IFr Proposed Coatiols for EmissaaB of*
Toxic Metal*
A. Overview
As in the proposed rule on t&e burning-
of hazardous waste im boilers and
industrial furnaces {see 52 FR 16382
(May 6,1987); and 5* FR 43718 (October
26,1989))^ EPA i» proposing ta coatrol
metals' emissions by requiring a site-
specific risk analysis when metals.
emissions; for feed rates) exceed
conservative Screening Limits. EPA
developed the Screening limits to , . •
minimize the need for conducting site-
specific risk assessments* thereby/ , :
reducing the burdem to applicants, and
permit officials., When the Screening
limits are e-xeaededi the applicant
would be ie<|uiredta conduct a site—
specific; risk assessment that ,
demonstrates that the potential
exposure of the maodmum exposed
indlvidaal t0 earcinagenic and
noncarcinogenic metals does not result
in an exceedance of reasonable
acceptable marginal additional risks,,
namely:
• That exposure to all carcmogeimr metals,
be Bmited suefr that the stmt of the excess
risks attributable fa ambient concentrations;
of these metals, dees not exceed! an additional
lifetime individual risk (tat the (JpotentialJ •
maximum exposed individual)! of KT5""; andi
• That exposure to each, noncarcinogenic
metals be limited such that exposure (to the
[potential) maximum exposed; indivrdud),
does not. exceed the reference air
concentration (RA.CJ for tie metal.
B. Metals a/Coneem
Although the limited data available OH
metals eomposrtion ofHiemerated waste
indicates that some of the 52 Appendix
Vffl metals may not pose unacceptable
health risk p.e;, either because no waste
concentration'data are available for a
particular metal or because the
available data radicate that a metal Is
not present at a particular facility at
levels that would pose unacceptable
risk), EPA nonetheless is proposrag
standards to control emissions of all 12
Appendix ¥111 metalsv except for
selenium and nickel as discussed below.
We believe that controls are needed for
ithe other 1Q metals—foe-carcinogens
arsenic,, beryBiumr cadmitEm, and
chromium Wand the?naneareihogens
antimony/, barium, lead. mereuEy, silver,,
and thallium—because our waste. ' • .
cpmposiaoai data base is both limited
and! Qutclatedt especially eonsideriiig the.
Agency,'® efforts [and statutory/ ..-• ..'-.
mandatesl to? reguirje fEeataiertt oi waste,
oftentby/ mcineratiQi^ prior to< land
disposal. We have m® assurance that
• any partLcuiaF waste ta be burned m art
incinerator would np,t contain, levels of
any o£ tlie 10. metals thai could result ia
unacceptable healtht risk. Rather fean
establishing eoiitrols for the four or five
key mefcils le.g^ aisenic,, cadmium,
chromiuisa VI,, and lead] and requiring
permit o-fficials to'dtetermine on a case-
by-case basis whether other metals are
present (it levels that eo,uld pose
unaccep table risk and controlling those-
emissions under the Section 3005{eM3J
omnibus pravisioa of HSWA [codified
at § 27Qi; J2(bl(2.)3* we'believe it is more,
straightforward and less burdensome on
both applicants and permit officials ta
establish controls for all 10 metals. We
note that although EPA proposed to
control boiler and furnace emissions
only, for the metals; arsenic,, cadmium,,
chromium, and leadl and to require
permit waiters to. determine the need to.
control other metals on, a case^by-case
basis [ses, 52, FE. 170Q5];,, the Agency has
requested comment ia a supplemental
notice ta, the bofler/rurna.ce proposed
rules on promulgating control's on all 10
metals. See 54 FH 43718 [October ZS,
1989);.' t '.
The basis for corrtroHirig' emissicms' of
chromium only fe the hexavalent form
and for not establishing controls for
nickel and selenium is discussed: below,
1. Cfrnyim'um. We have' assumed'' that
chromium is emitted nr its most potent
careoiogenic form, hexavafent
chromium. We believe this: assumption'
is consei'vative, but reasonable at this
tune for the purpose of determMing
whether chromium' emissions could pose
significant risk. , .
Chromium is Bkely to be emitted fla
either the Mghfy eaEcmogenic,
hexavalent state or m the relatively IQW-
toxicity Itrivalent state. (The data
available to ESA at this time are
inadequate to; classify/ the teivaleM
chromium: compounds) as to their'
40 Additive effects of carcihogenfc compounds
are considered by sununingtfie risks for all
carcinogens to estimate the aggregate risk to, tfte-
mos t exposed: individuciltlWErf. , .
** fii aefecf£ng.ai&!e thresfiolii of 10^" forthese
rules. EPA considered risk u&eshoMs in Hie range of
,
, hexavatant state emild be expected ta
result fecimi. combusMsn because ife
represents ttte more oxidized state,
some investigators speculate feat most '
of the chromium is likely to be emitted
in the trivalent state given, that the
hexavalent sjate is highly reacthre andl».
thus,, Mksdy ta be reduced to; the tifcalent
states Heiwever. preKminary/ ..
investigattiQris *2 indicate that : 50 percent
Three of tfie text, feet Agency requests comment on
alternative risk thresnoldff.
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Federal Register / Vol. 55, No. 82 /; Friday, April 27, 1990 ,/• Proposed Rules
or more of chromium emissions from
hazardous waste incinerators can be in
the hexavalent state when chlorinated
wastes are burned. Unfortunately, data
on hexavalent chromium emissions is
sparse because a reliable emissions
sampling and recovery methodology has
only recently been developed. 43 Thus,
the Agency is not able to establish at
this time a reasonable, worst case
assumption for the fraction of chromium
emissions that may be hexavalent, other
than assuming 100 percent of chromium
emissions are hexavalent. Consequently,
the proposed emission controls under
under the Emissions Screening Limits
and Site-Specific Risk Analysis
alternative would be based on
emissions of total chromium unless the
applicant conducts emissions testing
capable of reliably determining actual
chromium emissions in the hexavalent
state (e.g., by using the soon-to-be-
validated methodology referenced
above). In such a case, the Emissions
Screening Limits and Site-Specific Risk
Analysis standards would be applied to
the measured hexavalent chromium
emissions. (The Feed Rate Screening
Limits, however, would apply to the
total chromium present in the waste
because emissions testing is not used to
comply with these limits.)
As additional data become available
on the health effects of chromium
emissions from combustion sources, the
Agency will consider what, if any,
amendments would be appropriate to
the rule proposed today. For example, if
additional data indicate that hexavalent
chromium emissions invariably account
for less than 75 percent of total
chromium emissions, the Screening
Limits could be adjusted accordingly
(i.e., by increasing them by 25 percent).
The Agency specifically requests data
(using validated procedures)
documenting hexavalent chromium
emissions from incinerators burning
hazardous waste.
2. Nickel. Nickel carbonyl and nickel
subsulfide are suspected human
carcinogens. The Agency is continuing
to study other nickel compounds with
respect to carcinogenic potency. Given
that neither nickel carbonyl nor nickel
subsulfide is likely to be emitted from a
conventional incinerator because of the
Vcnturi Scrubber/Packed Column Scrubber, Vol. I,
Technical Results", April 1989.
«« glclnsbetgor, S. C. and Carver. A. C, Entropy
Environmentalists, too, and Knoll J. E., ct al, US
EPA. "Sampling and Analytical Methodology for
Measurement of Low Levels of Hexavalent
Chromium from Stationary Sources", Paper
pn»entcd »l EPA/AWMA Symposium at Raleigh,
N. C, May 1889, as revised by draft dated
November 1ft 1983, entitled "Method Cr+«—
Determination of Hexavalent Chromium Emissions
From Stationary Sources".
highly oxidizing environment, we are
not proposing controls for nickel. If the
Agency determines that nickel
compounds in the oxidized state may be
human carcinogens or that nickel
carbonyl or nickel subsulfide could, in
fact, be emitted from some incinerators,
we will propose to control those
compounds. We note however, that we
are proposing today to include two
innovative types of incinerators—
infrared and plasma arc—in the
definition of incinerator. These devices
may not use oxidation to thermally
destruct organic compounds and, thus,
could conceivably emit nickel in
reduced species such as carbonyl and
subsulfide. Given that we do not have
fully developed and validated sampling
and analysis procedures -specifically for
these compounds, we would have to
assume conservatively that any nickel
emitted from these devices was
carbonyl or subsulfide. We specifically
request comment on whether these
noncombustion incinerators are likely to
emit significant levels of nickel carbonyl
or subsulfide. If so, we also request
information on the availability of
validated sampling and analysis
procedures for these compounds.
3. Selenium, At the present time, the
Agency does not have the health effects
data needed to establish acceptable
ambient levels for selenium. At such
time that health effects data become
available, selenium emissions will be
controlled, if warranted.44
C. Metals Emissions Standards 4S
The metals emissions-standards
require site-specific risk assessment to
demonstrate that metals emissions will
not: (1) result in exceedances of the
reference air concentrations (RACs) for
noncarcinogens at the potential MEI;
and (2) result in an aggregate increased
lifetime cancer risk to the potential MEI
of greater than 1 X10~5 4S- As discussed
above, the RACs for noncarcinogens
and risk specific doses (RSDs) for
carcinogens are presented in Appendix
•H of the boiler/furnace supplemental
notice. See 54 FR 43763 (October 26,
1989).
To reduce the burden on applicants
and permitting officials, EPA has
•*•* Memo from Reva Rubenstein, Chief, Health
Assessment Section, Technical Assessment Branch
to Bob Holloway, Chief Combustion Section, Waste
Treatment Branch. EPA, entitled "Hydrogen
Bromide, Hydrogen Fluoride, Selenium, and Lead,"
October 16,1987.
*5 This discussion has been taken virtually
verbatim from the October 26,1989 boiler/furnace
supplemental notice (see 54 FR 43758-60).
"In selecting a risk threshold of 10"5 for these
rules, EPA considered risk thresholds in the range of
10'* to 10"e. As discussed in Section I.D. of Part
Three of the text, the Agency requests comment on
alternative risk thresholds.
developed conservative Screening
Limits for metals emissions (and feed
rates) as a function of terrain adjusted
effective stack height, terrain, and land
use. See discussion below. If the
Screening Limits are not exceeded, site-
specific dispersion modeling would not
be required to demonstrate conformance
with the proposed standard.
If the Screening Limits are exceeded,
the applicant would be required to
conduct site-specific dispersion
modeling in conformance with
"Guideline on Air Quality Models
(Revised)" (1986), and Supplement A
(1987), EPA Publication Number 450/2-
78-Q27R, available from National
Technical Information Service,
Springfield, Virginia, Order Nos. PB 86-
245286 and PB88-150958. We are
proposing to incorporate that document
by reference in § 270.6(a).
The use of physical stack height in
excess of Good Engineering Practice
(GEP) stack'height is prohibited in the
development of emission limitations
under EPA's Air Program at 40 CFR
51.12 and 40 CFR 51.18. We propose to
adopt a similar policy by limiting the
height of the physical stack for which
credit will be allowed in complying with
the metals (and other) standards (i.e.,
both site-specific dispersion modeling
and Screening Limits). GEP identifies the
minimum stack height at which
significant adverse aerodynamic effects
are avoided. Although higher than GEP
stack heights are not prohibited, credit
will not be allowed for stack heights
greater than GEP. Good Engineering
Practice (GEP) maximum stack height
means the greater of: (1) 65 meters,
measured from the ground-level
elevation at the base of the stack; or (2)
Hg=H+1.5L.47
where:
Hg=GEP minimum stack height measured
from the ground-level elevation at the
base of the stack;
H=height of nearby structure(s) measured
from the ground-level elevation at the
base of the stack;
L=lesser dimension, height or projected
width, of nearby structure(s).
If the result of the above equation is
less than 65 meters, then the actual
physical stack height, up to 65 meters,
could be used for compliance purposes.
If the result of the equation is greater
than 65 meters, the physical stack height
considered for compliance purposes
cannot exceed that level.
*7 We note that this equation also identifies the
GEP minimum stack height necessary to avoid
building wake effects. EPA recommends the
application of GEP to define minimum stack heights
to minimize potentially high concentration of
pollutants in the immediate vicinity of the unit.
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• 17am
EPA requests comment on this; use of
GEP maximum stack height We note
that although aa owner or operator
could increase his physical stack height
up to the GEP maximum, ta achieve
better dispersion and a higher allowable
emission rate,, he should! Srst consider
that that EPA plans to establish (after
proposals and opportunity for comment)
a best demonstrated technology {BDTJ
particulate standard that is likely, to be
0.01 to 0.22 gr/dsef. Thus, he would be
more likely to upgade his emission;
control equipment to state-of-the-art
control rather than increase stack
height.
EPA bpeoifieally requests comments
on how many facilities are likely to
exceed the Screening Limits discussed
below and, thus, would conduct site>-
specific dispersion modeling ta comply
with the proposed rale.. Further, we
request information! on the changes to
equipment and operations that would be
required to comply with the Screening
Limits if the provision for site-specific
dispersion: modeling was. not available.
D. Screening Limits
•'. EPA developed conservative
Screening Limits for metals emission
rates (and feed rates j ta minimize the
need for site-specifier dispersion
modeling, and thus,, reduce the burden
on applicants- and permitting.*81 The
Screening Limits are provided as a
function of terrain-adjusted effective
stack height, terrain, and urban/rural
classification as discussed below. The
Screening Limits would be included in .
the "Risk Assessment Guideline for
Permitting Hazardous Waste Thermal
Treatment Services"1 fRAG} which
would be incorporated bjr reference in
the rule at §27016, See sectton LH of
part Three for a discussion of the RAG.
The Screening Limits proposed today
for incinerators- are identical to those
proposed for bowers and industrial
famaees in; the October 26^ 1989
supplemental notice. See 54 FR 4375S-62
(appendices F and GJ for discussion; of
the derivation and implementation of
the Limits- and pages 43745-55 [appendix
E) where the Limits are presented. We
are not repeating that information in
today's notice.
151. Proposed Controls; for Emissions of
Hydrogea Chloride
A, Summary of Existing Standard'
Highly-chlorinated wastes from the
manufacturing of organic chemicals, t
highly-chlorinated spent solvents, and
solvent recovery distillation bottoms, are
routinely incinerated in hazardous
waste insinerators. Chlorine in
hazardous waste produces hydrochloric
acid (HC1J, upoa combustion! which can
cause serious health hazards if it is not
removed with flue gas cleaning
equipment such as, wet scrubbers.
(Other halogens of potential health
concern such as, fluorine and bromine
are also common constituents.rat
hazardous wastes However, EPA does
not have adequate health data upon
which to base a regulation at this time.
When data becomes; available,. EPA
intends to revise the regulation to
include other halogens; if we determine
that they can pose unacceptable health
risks.48 .-...'•:.
Under 15PArs existrng rales, anl
incinerator burning hazardous waste
must control HC1 emissions to the larger
. of either 1.8 kilograms [4 poundsjper
hour or 1 percent of the HC1' in the stack
gas prior JEo entering any pollution
control eqiiiipment This performance
standard at i 264.343 (bj is, based on. the
capability of wet scrubbers; to remove
acid gas, iwith the. expectation, that the
industrial threshold limit value for
hydrogen chloride would rarely,, if ever,
be exceeded.
B. The Existing Standard May W>t Be
Fully Protective m Certain Situations
Risk assessment using; reasonable,
worst-case facilities discussed
previously indicates that incineration of
hazardous; waste with total chlorine
levels of 35 percent (350$00 ppml can
pose exceedances of tfieHCL short term
reference airconcentafions (RACsJeven
when 99 percent of HC1 emissions are
assumed to be removed from the stack
gas as currently required by
§ 264.343(bJ. See Table 3'. Long term (le.,
annual} reference air concentations,
however, lire not likely to be exceeded.
In addition the de mnrimis HCI emission
rate that triggers the 99 percent removal
requirement, 4 Ib/hr, may not provide -
adequate protection. See table E-9 of
appendix E in the boiler furnace
.supplement notice [54 FR 43751J
indicating that when terrain adjusted
effective stack height is less than 3ff m, in
noncomplex terrain and 50 m m complex
terrain; a4lb/hr emission rate could
result in a:n exceedance of the short-
termRAC:,
48 We note Shat the Screening Limits are designed
to be conservative and would likely limit emissions
by a factor of 2. to 20 times lower than would be
allowed by site-specific dispersion modeling..
49 Memo from Rev® Rubensteiiu Chief. HeaHh
Assessment Section, Technical Assessment Branch;
to Bob Holloway* Chief. Combustion Section, Waste,
Treatment Branch,. EPA, entitled "Hydrogen
• Bromide,. Hydrogen Fluoride, Selenium, and Lead,"'
Octoberie, :E987. '
TABLE 3.—MAXIMUM CONCENTRATIONS OF HCF FOR. SELECTED WORST-CASE FACILITIES
Dispersion coefficient
jig/mS/g/sec'S'
minuta
639.04
6Q4.Q7
264.92
f 70.44
Dispersion coefficient
i (ig/mS/g/sec, annual
6.85
10.48
3.32
2:72
Capacity ib/hf
; . 60a
' 820
2920
3241
| Ambient cone, fig/
ra3 a minuta
169.08s
218.44
34T.14
'• • 243'.6t,
: Ambient cone, fig/
. ma annual
• 2.34
r 3.79
4.28.
3.89
[ RteframbfemVRAC3
i minuts1
' '' j " '- " • i.i3
!" t.46
--.!• - ... 2.2T
i 1^52;
Risk ambient/RAG.
; annual
I 0.1S
0.25-
; 0.2?
; 0.2S
The RAG for annual exposure to HCI
is 7 ftgfas. * tto and is based on the
threshold of respiratory effects.
Background levels were considered ta
50 Memo dated Majt 4^1989; fromMtkeUotreson^
EPA Office of Health and Environmental
assessment, tai the EfD Workgroup,, entitled "RfB
Meeting of February 16,1989".
be insignificant given; that there are not
many large sources of HG1 and that this
polIutantgeneraHy/should not be
transported over long, distances, in the
lower atmosphere;. The RAG for 3-
minute exposures is 15O pg/m
6' Memo from Lisa Ratclifj EPA. ta Dwight
Hlusfick, EPA. entitled: "Short-term Health-based!
Number for Hydrogen Chloride," Sept. 15; 1386.
C. Request for Comment on Controls for
Free Chlorine' :
We noted in the proposed boiler/
furnace rules (52 Fr 1700ft (May 6, i987]J
that we thought there was a remote
possibility that free chlorine (Ck) could
be emitted from burning cHorined
wastes if there was insufficient
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Federal Register / VoL 55. No^ 82 /Friday, April 27, 1990 / Proposed Rules
hydrogen available (i.e., from other
hydrocarbon compounds or water
vapor) to react with all the chlorine in
the waste. We understand, however,
that free chlorine emissions have been
detected at a number of hazardous
waste Incinerators. Free chlorine
emissions are of concern because CU is
a potent irritant to the respiratory
system. To address this problem, we are
proposing today to amend § 264.343(b)
so that the existing 99% removal
standard would apply to both HC1 and
Cla. This standard could be met by
providing more hydrogen in the waste or
supplementary fuel or the addition of
superheated steam to the stack gas. In
addition, as with HC1, we are proposing
to require a health-based check to
ensure that the technology-based
standard is protective. Thus, the
applicant would be required to
demonstrate that the maximum exposed
individual (MEI) is not exposed to Clz
concentrations exceeding the proposed
annual average reference air
concentration (RAG) of 0.4 ug/m 8.52 As
for HC1, the RAG is based on 100% of the
interim inhalation RfO because other
sources of CU are expected to have
little or no effect on background levels
due to the short life of Cb in the
atmosphere.
As with the HC1 standards,
compliance with the health-based Clz
standard would be demonstrated by: (1)
emissions testing and dispersion
modeling; (2) emissions testing and
conformance with CU emissions
Screening Limits; or (3) waste analysis
and conformance with chlorine feed rate
Screening limits. The Clz Screening
Limits would be developed using the
same methodology used for the metals
Limits (e.g., same dispersion or dilution
factors; feed rate limits assume all
chlorine on the feed is emitted as Clz).
(The dispersion factors used to establish
the HC1 Screening Limits were not used
because they are based on short-term
(i.e., 3-minute) exposures. A short-term
RAG is not yet available for Clz.) Given
that the RAG for Ck is 1.33 times the
RAG for mercury, the Screening Limits
for C!a would be 1.33 times the Limits
established for mercury in Appendix E
of the boiler/furnace supplemental
notice. See 54 FR 43745 (October 26,
1909).
D, Basis for Proposed Standards
The basis for the proposed standards
HC1 standards for incinerators is
identical to 'that proposed for boilers
and furnaces as discussed in the
October 26,1989, supplemental notice.
In addition, the implementation of the
controls and the controls themselves
(i.e., compliance with feed rate or
emission rate Screening Limits, or
demonstration by site-specific
dispersion modeling that the RAC is not
exceeded at the MEI) would be identical
for boilers/furnaces and incinerators.
See Appendices, E, F, and G of the
supplemental notice at 54 FR 43751-62.
Those discussions and information are
not repeated here, but are to be
considered fully applicable.
W. Proposed Controls for Emissions of
Products of Incomplete Combustion
A: Hazard Posed by Emissions of
Products of Incomplete Combustion
(PICs)
The burning of hazardous waste
containing toxic organic compounds
listed in Appendix VIII of 40 CFR part
261 under poor combustion conditions
can result in substantial emissions of
compounds that result from the
incomplete combustion of constituents
in the waste, as well as emissions of the
original compounds which were not
burned. The quantity of toxic organic
compounds emitted depends on the
concentration of the compounds in the
waste, and the combustion conditions
under which the waste is burned.
Data on typical PIC emissions from
hazardous waste combustion sources
were compiled and assessed in recent
EPA studies.63 s* These studies
identified 37 individual compounds in
the stack gas of the eight full-scale
hazardous waste incinerators tested, out
of which 17 were volatile compounds •
and 20 semivolatile compounds. Eight
volatile compounds (benzene, toluene,
chloroform, trichloroethylene, carbon
tetrachloride, tetrachloroethylene,
chlorobenzene, and methylene chloride),
and one semivolatile compound
(naphthalene) were identified most
frequently in over 50 percent of the tests.
Some of these compounds are
carcinogenic. It was found that PIC
emission rates vary widely from site-to-
site which may be due, in part, to
variations in waste feed composition
••Memo from Prlscilla Halloran, EPA, to Dwight
HluiUdc. EPA. (mltitled "Health-Based Air
Concentration! for Chlorine and N-nitroso-n-
mcthylucm", dated January 4,1990.
•* Wallace, D. et al., "Products of Incomplete
Combustion from Hazardous Waste Combustion,"
Draft Final Report, EPA Contract No. 68-03-3241,
Acurex Corporation, Subcontractor No. ES 59689A,
Work Assignment 5, Midwest Research Institute
Project No. 8371-L{1), Kansas City, MO, June 1988.
" Trenholm, A., and C. C. Lee, "Analysis of PIC
and Total Mass Emissions from an Incinerator,"
Proceedings of the Twelfth Annual Research
Symposium on Land Disposal, Remedial Action,
Incineration, and Treatment of Hazardous Waste,
Cincinnati, OH, April 21-23,1986, EPA/600-9-66/
022, pp. 376-381, August 1988.
and facility size. The median values of
the nine compounds mentioned above
range from 0.27 to 5.0 mg/min. Using a
representative emission rate of 1 mg/
min, the stack gas concentration for
PICs in a medium-sized facility (250 m3/
min combustion gas flow rate) would be
4 /ig/m3 (0.004 u.g/1).
The health risk posed by PIC
emissions depends on the quantity and
toxicity of the individual toxic
components of the emissions, and the
ambient levels to which persons are
exposed. Estimates of risk to public
health resulting from PICs, based on
available emissions data, indicate that
PIC emissions do not pose significant
risks when incinerators are operated
under optimum conditions. However,
incinerator do not always operate under
optimum conditions. In addition, only
limited information about PICs is
available. PIC emissions are composed
of thousands of different compounds,
some of which are in very minute
quantities and cannot be detected and
quantified without very elaborate and
expensive sampling and analytical
(S&A) techniques. Such elaborate S&A
work is not feasible in trial burns for
permitting purposes and can only be
done in research tests. In addition,
reliable S&A procedures simply do not
exist for some types of PICs (e.g., water-
soluble compounds). The most
comprehensive analysis of PIC
emissions from a hazardous waste
incinerator identified and quantified
only approximately 70 percent of
organic emissions. Typical research-
oriented field tests identify a much
lower fraction—from 1-60 percent. Even
if all the organic compounds emitted
could be quantified, there are
inadequate health effects data available
to assess the resultant health risk. EPA
believes that, due to the above
limitations, additional testing will not, in
the foreseeable future, be able to prove
quantitatively whether PICs do or do not
pose unacceptable health risk.
Considering the uncertainties about PIC
emissions and their potential risk to
public health, it is therefore prudent to .
require that incinerators operate at a
high combustion efficiency to minimize
PIC emissions. Given that carbon
monoxide (CO) is the best available
indicator of combustion efficiency, and
a conservative indicator of combustion
upset, we are proposing to limit the flue
gas CO levels to levels that ensure PIC
emissions are not likely to pose
unacceptable health risk. In cases where
CO emissions exceed a proposed de
minimi's limit, higher CO levels would
be ajlowed under two alternative
approaches: (1) if hydrocarbon (HC)
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Federal Register / Vol. 55; &di^^/.^(^^^ril27, 1990 - / J
concentrations in the stack gas do not
exceed a good operating practice-based.
limit of 2O ppmv; or (2) if the applicant
demonstrates that HC emissions are not
likely to pose unacceptable health risk
using conservative, prescribed risk
assessment procedures; Although we
prefer the technology-Based approach
for reasons discussed below, we are
requesting comment on the health-based
alternative aa well.
B. Existing, Regulatory Controls
Section 264.345 of the existing
regulations requires that the permit must
limit the CO level in the stack exhaust
gas based an the trial bum when
demonstrating eonfonnance with the
destruction and removal efficiency
(DRE} standard for principal organic
hazardous constituents (PQHCs}.
Section 264.347 requires that CO
emissions be monitored continuously at
a point downstream, of the combustion
zone and prior to release to the
atmosphere; and § 264.345 requires that
the incinerator must be.equipped with a .
functioning system to cut off the waste
feed automatically when the CO limit is '
' exceeded. Thus, die existing regulations
do not specify an upper limit for CO, but
rather limit CO to the levels that occur
during the trial burn. The regulations do
not specify limits for PIC emissions nor
require analysis, of risks from such
emissions. PICs are assumed to be
controlled by the DRE standard for
POHCs. Although CO levels may often
be at levels that represent high
combustion efficiency (e.g., below 100
ppmv, the de minimis Emit proposed
today] when demonstrating
confbrmance with the DRE standard,
there is no« assurance that such low CO-
levels will always occur. Test data
indicate that 99199 percent BRE can be
achieved when incinerators- {and boilers
and industrial furnaces J are operating
under upset combustion conditions as
evidenced' by high CO stack gas levels
. and even smoke. Apparently, oiganie
constituents in the waste are readily .
destroyed in the flame zone, but
combustion by-products or PICs may not
be exposed to adequate time,
temperature, and turbulence to be
reduced to low levels. Thusv existing
regulatory provisions may not be
adequate to ensure that PICs do not
pose unacceptable risk,
C. Basis for CO Standards
• EPA is proposing to limit flue gas
carbon monoxide levels to ensure that
• incinerators: that burn hazardous waste
operate at high combustion efficiency to
reduce the potential .risk from emissions
of PICs. EPA believes that a CO level of-
lOOppnw represents high combustion
efficiency operations that would
virtually ensure that PIG emissions are
limited to levels that pose acceptable
risk to public health. However, all
incinerators [e.g., those that handle
containers of volatile waste or that have
fluid beds) may not be able to readily
meet a 100' ppmv CO' limit. Because we
have not been able to establish: a direct
correlation between CO, PIC emissions,
and the resulting health risk (i.e., when
CO is 150 or 200 ppmv we are uncertain,
if PIC emissions are likely to pose
significant risk), we are proposing an
approach to waive the CO limit of 100
ppmv. Under the waiver* any CO level
achieved during the DRE. trial burn.
would be allowed provided that
emissions of hydrocarbons (HCJ do not
exceed acceptable levels. •
1. Summary of Proposed Controls,
EPA is proposing, a two-tiered approach
to control PICs by limiting stack of gas
CO levels. The first tier requires
compliance with a CO limit of 100 ppmv
on an hourly rolling average/5 basis. If
a facility meets this CO level, during the
trial burn, 10& ppmv will be the permit
limit. If this CO limit cannot be met, the
facility could operate at higher
permitted CO levels under a Tier BE
waiver. The 100 ppmv CO'limit-would
be waived .under two alternative
approaches^ [1} a demonstration that
hydrocarbon (HC) emissions are not
likely to pose unacceptable health risk
using conservative, prescribed risk .
assessment procedures; or (2) a
technology-based demonstration that
the HC concentration in the stack gas
does not exceed a good operating
practice-based limit of 20 ppmv.
Although we prefer the technology- -
based approach for reasons discussed
below, we request comment on the
health-based1 alternative as welL
The CO limits for either Tier I or Tier
H must be corrected to dry stack gas and
7 percent oxygen in the stack gas. The
correction to drygas is necessary only
for instruments that measure CO on a
wet basis. This correction factor for
humidity would initially be determined1
during the trial burn and annually
thereafter unless specified otherwise m
the permit. The oxygen correction factor
must be determined at intervals
specified in the permit (not less
frequently than annually J. The oxygen
and humidity correction factors would
be applied continuously. {The basis for
the 7 percent oxygen correction factor is
discussed in, section EvVC.4 below.}
• _ The-existing regulations-already ,
require that the hazardous waste feed
must be cutoff automatically when, the
permitted CO limits are exceeded.
Today's proposal adds a requirement
thathazaidouswasteburningmay.be
resumed when CO levels are brought
within the permitted limits* When the
hazardous waste feed is cut off,
combustion chamber temperatures
specified in the permit and the air
pollution control equipment functions
must be maintained as long as any
waste remams in the combustion '
chamber. For incinerators with a
secondary combustion chamber* we
request comment on whether
temperatures should be maintained in.
both the primary and secondary
• chambers to control organic emissions
when the waste feed is cutoff. Auxiliary
fuels used to maintain temperatures
must not contain hazardous waste other
than waste'exempt from the substantive
requirements of subpart O under
provisions of § 264.340[b),
EPA specifically requests comment on,
how to apply the requirement to
maintain: temperature following a waste
feed cutoff,, as well as other standards
proposed, today, to batch incinerators*
2. Use of CO Limits to Ensure Good
Combustion Conditions. By definition,
low GO flue gas levels are indicative of
an. incinerator (or any combustion
device) operating at high combustion
efficiency. Operating at high combustion
efficiencjr helps ensure minimum
emissions of unburned (or incompletely
burned) organics.58 In a simplified view
of combustion of hazardous waste, the
first stage is immediate thermal
decomposition of the POHCs in the
flame to. form other, usually smaller, •
'compounds, also referred to as PICs.
These PICs are generally rapidly
decomposed to form CO.
The second stage of combustion "
involves the oxidation of CO to COz
(carbon dioxide). The CO: to CO2 step is
the. slowest (rate controlling) step to the
combustion process because CO is
considered to be more thermally stable
(difficult to oxidize} than other
intermediate products of combustion of
hazardous waste constituents. Since fuel
Is being fired continuously, both
combustion stages are occurring
simultaneously.
f- Am hourfyrollmgAverage is, the arithmetic ;
mean of the 60 most recentl-minuta average values
recorded! hjr the continuous monitoring system.
» eo Given lhai CO is aigross indicator of
combustion performance, limiting CO may not
absolutely minimize PIC emissions. This- is because
PICs can reiiult &QH» small pockets within the
combustion zone where adequate time, temperature,
i and turbutencehaye not been providedrto oxidize
completely. She combustion products of the POHCs.
Available; data, however, indicate that PIC
emissions do" notpose significant risk-when;
combustion devices are operated athigh .
combustion efficiency/. EPA fa conducting- additional'
field and pi] ot scale testing to address this issue.
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Federal Register / Vol. 55, No. 82 / Friday, April 27, 1990 / Proposed Rules
Using this view of waste combustion,
CO flue gas levels cannot be correlated
to DRE for POHCs and may not
correlate well with PIC destruction. As
discussed below, test data show no
correlation, between CO and DRE, but
do show a slight apparent correlation
between CO and chlorinated PICs, and a
fair correlation between CO and total
unbumed hydrocarbons. Low CO is an
indicator of the status of the CO to CO2
conversion process, the last, rate-
limiting oxidation process. Since
oxidation of CO to CO* occurs after
destruction of the POHC and its (other)
intermediates (PICs), the absence of CO
is a useful indication of POHC and PIC
destruction. The presence of high levels
of CO in the flue gas is a useful
indication of inefficient combustion and,
at some level of elevated CO flue gas
concentration, an indication of failure of
the PIC and POHC destruction process.
We believe it is necessary to limit CO
levels to levels indicative of high
combustion efficiency because we do
not know the precise CO level that is
indicative of significant failure of the
PIC and POHC destruction process. It is
possible that the critical CO level may
bo dependent on site-specific and event-
specific factors (e.g., fuel type, air-to-fuel
ratios, rate and extent of change of these
and other factors that affect combustion
efficiency). We believe limiting CO
levels is prudent because: (1) it is a
widely practiced approach to improving
and monitoring combustion efficiency;
and (2) most well designed and operated
incinerators can easily be operated in
conformance with the proposed Tier I
CO limits of 100 ppmv.
The Tier I CO limit proposed today
specifies a 100 ppmv CO limit in the
permit even though the CO level during
the trial burn will be lower (i.e., by
definition, under Tier I). EPA considered
this issue carefully and the proposal is
based on three considerations, First,
DRE will not be reduced below the
levels specified in § 264.343(a)(l) for
POHCs by the proposed CO limits.
Second, many incinerators run very
efficiently during a trial burn and
indicate less than 10 ppmv of CO
emissions. It may not be possible to
achieve that high degree of efficiency on
a consisent basis and specifying such
low trial burn CO values may result in
numerous hazardous waste feed cut-offs
due to CO exceedances. Third, the,
emission of PICs from incinerators has
not been shown to increase linearly at
such low CO levels. In fact, the trial
burn data indicate that total organic
emissions are consistently low (i.e., at
levels that pose acceptable health risk)
when CO emission levels are less than
100 ppmv. Two studies show that no
. measurable change in DRE is likely to
occur for CO levels up to 100 ppmv. The
first study generated data from
combustion of a 12 component mixture
in a bench scale facility.57 The CO
levels ranged from 15 to 522 ppmv
without a significant correlation to the
destruction efficiency for the compounds
investigated. The second study was
conducted on a pilot scale combustor.68
Test runs were conducted with average
CO concentrations ranging from 30 to
700 ppmv. When the concentration was
less than 220 ppmv no apparent
decrease in DRE was noticed, but higher
CO concentrations showed a definite
decrease in DRE. EPA specifically
invites comments on whether the permit
should limit CO according to trial burn
values in lieu of the limits specified
here.
3. Supporting Information on CO as a
Surrogate for PICs. Substantial
information is available that indicate
CO emissions may relate to PIC
emissions.
Combustion efficiency is directly
related to CO by the following equation:
Combustion Efficiency (CE)=
percent CO2
percent CO2 + percent CO
[100]
CE has been used as a measure of
completeness of combustion.89 EPA's
regulations for incineration of waste
PCBs at 40 CFR 761.70 require that
combustion efficiency be maintained
above 99.9 percent. As combination
becomes less efficient or less complete,
at some point, the emission of total
organlcs will increase and smoke will
eventually result. It is probable that
some quantity of toxic organic
compounds will be present in these
organic emissions. Thus, CE or CO
levels provide an indication of the
potential for total organic emissions and
possibly toxic PICs. Data are not
available, however, to correlate these
variables quantitatively with PICs in
combustion processes.
" Hall D.L. et nl. "Thermal Decomposition
Properties of « Twelve Component Organic
Mixture", Hazardous Waates & Hazardous
Material!, Vol. 3, No. 4 pp 4431-449.1988.
" Wtterland, L.R. "Pilot-scale Investigation of
Surrogate Means of Determining POHC
Destruction" Final Report for the Chemdal
Manufacturer*' Association. ACUREX Corporation,
Mountain View, California, July 1983.
** Wo specifically request comments on whether
Several studies have been conducted
to evaluate CO monitoring as a method
to measure the performance of
hazardous waste combustion. Though
correlations with destruction efficiency
of POHCs have not been found, the data
from these studies generally show that
as combustion conditions deteriorate,
both CO and total hydrocarbon
emissions increase. These data support
the relation between CO and increased
organic emissions discussed above. In
one of these studies,80 an attempt was
made to correlate the concentrations of
CO with the concentrations of four
common PICs (benzene, toluene, carbon
tetrachloride, and trichloroethylene) in
stack gases of full scale incinerators. For
a plot of CO versus benzene, one of the
most common PICs, there is
combustion efficiency, as defined above in the text
(i.e., considering both CO and COa emissions)
should be used to control THC emissions rather
than CO alone.
80 Trenholm, A., P. Gorman, and G. Jungclaus,
"Performance Evaluation of Full-Scale Hazardous
Waste Incinerators, Vol. 2—Incinerator
Performance Results." EPA-800/2-84-181b, NTIS
No. PB 85-129518, November 1984.
considerable scatter in the data
indicating that parameters other than
CO affect the benzene levels. However,
there is a trend in the data that suggests
that when benzene levels are high, CO
levels also are high. The converse has
not been found to be true; when benzene
•levels are low, CO levels are not always
low. Similar trends were observed for
toluene and carbon tetrachloride, but
not for trichloroethylene. In the pilot-
scale study by Waterland cited earlier,
similar trends were observed for
chlorobenzene and methylene chloride
and in another study 61 similar trends
were observed for total chlorinated
PICs. These data support the conclusion
that when the emission rates of some
commonly identified PICs are
sufficiently high, it is likely that CO
emissions will also be higher than
typical levels.
More importantly, however, available
data indicate that when CO emissions
" Chang, D.P. et al., "Evaluation of a Pilot-Scale
Circulating Bed Combustor as a Potenial Hazardous
Waste Incinerator," APCA Journal, Vol. 37, No. S, -
pp. 286-274, March 1987.
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Federal Register / Vol. 55w N6.:82 I "Fridky, '
are low (e.g.,,. under 100 ppmv), PIG
emissions are always low (i.e., at levels •
that pose acceptable health risk). The
converse may not be true:: when CO is
high, PIC levels, may or may not be high.
Thus, the Agency believes that CO is a
conservative' indicator of potential PIC
emissions and,, given that CO monitoring
is already required in the present
regulations, the emission levels should
be limited to low levels indicative of
high combustion efficiency. (For those
facilities where CO emissions may be
high but PIC emissions low, we are
providing an opportunity under Tier n of
the proposed rule to demonstrate thatr in
fact, PIC emissions pose acceptable
health risks at elevated COlevels.),
D. Derivation of the Tier I CO Limit.
-The proposed Tier I de miaimis CO
limit of 100 ppmv was selected for a
number of reasons: (1) it is within the
range of CO levels that representhigh
combustion efficiency; (2). available field
test data indicate that PICs are" not
emitted at levels that pose unacceptable
risks when CO does not exceed 100
ppmv; (3) the 100 ppmv level is
consistent with the combustion ,
efficiency of 99.9 percent currently,
required by ElPA's PCB incineration
regulations codified at 40 CFR 761.70; (4)
it is the CO limit proposed for boilers .
and furnaces burning hazardous waste
(see 52 FR 16997 (May 8,1987), and 54
FR 43718 (October 26,1989)); and (5) it is
a level that the majority of well
designed and operated incinerators can
meet. These reasons are discussed
below. •
EPA regulations referred to above (40
CFR part 761) under the authority of the
Toxic Substance Control Act (TSCA) for
the incineration of PCB-Iaden wastes
require a minimum combustion
efficiency (CE) of 99.9 percent.
Combustion efficiency of 99.9 percent,
calculated as GO2/(CO2+CO),
translates to CO emissions levels of 801
to 125 ppmv corrected to 7 percent Oz,
depending on the fuel C/ET ratio. The
intent of the PCB combustion efficiency
rule is to minimize emissions: of
potentially toxic organics. Therefore, the
proposed 100 ppmv CO level for
hazardous wastes destruction is
consistent with the intent of the
regulations governing the incineration of
PCB wastes.
CO emission data from hazardous
waste incineration research and trial
burn tests also confirm the relationship
between CE greater than 99.ff percent
and CO levels less than 100 ppmv. The
combustion efficiencies hi all cases
where data were available were
calculated to exceed 99;9 percent, . .].
except for the test runs where CO
exceeded the proposed CO limit.
The data from the research tests of
eight incinerators cited earlier 62
showed that most incinerators easily
complied with the 100 ppmv proposed
limit with two exceptions. The first
: exception was a maximum hourly
average of 120 ppmv which came from
one test run out of four fit a test site.
Information was not available to
evaluate why CO levels were higher for
this test run; however, all the other three
runs at this site showed routine
compliance with the proposed limits.
The second exception came from data ,
for a rotary kiln that was fed containers
of volatile waste-. All three runs at this
site showed CO levels clearly higher
than the proposed limits. This
incinerator operated at a relatively
higher baseline CO level and also
exhibited frequent CO spikes as drums
of volatile waste were fed to the rotary
kiln.
Another data set on CO is contained
in the results of trial burn tests
conducted during permitting; of,
hazardous waste incinerators.63 Based
on an evaluation of these data, we
estimate that sqme incinerators could
fail the proposed CO limits. (Under
today's proposal, owners and operators
of these incinerators would be required
to demonstrate that their HC emissions
are acceptable). But* in general, the data
reviewed suggests that most hazardous
waste incinerators can easily achieve
the recommended CO limits.
Information was not available to
evaluate why the CO levels were higher
at some incinerators and not at others.
Reduction of these higher CO levels may
involve relatively simple change in some
cases, but may require significant
changes in operating conditions hi other
cases. Comments by incinerator
operators have indicated that certain
incinerator operators may have
difficulty achieving the proposed limits
without a substantial reduction in
capacity. The type of operations
specifically referred to are rotary kiln
incinerators that feed containers of
volatile waste, and fluidized bed
incinerators. Volatile hazardous waste
when batch fed in containers can
volatilize and burn rapidly creating a
momentary oxygen deficiency in the •
primary combustionchamber. A CO
62 Trenholm, A., P. Gorman, G. Jungclaua,
"Performance Evaluation of Full-Scale Hazardous
Waste Incinerators, Vol. 2—Incinerator
Performance Results/' EPA-600/2-84-181b, NTEJ
No. PB 85-129518, November 1984.
83 PEI Associates and JACA Corporation. "Permit
- Writer's Guide to Test Burn Data—Hazardous
Waste Incineration," USEPA Handbook, EPA/625/
6-86/012, September 1988.
spike generally occurs every time a
container in fed in the system and the
. cumulative; spikes could increase the
average GQ level to go= above 100 ppmv.
The average CO level is also affected by
the volatility of the waste, the quantity
"of waste fed in one batch, the frequency
at which bcLtches are fed, and the
volume of the combustion chamber, EPA
specifically requests comments from
incinerator operators about the
achievabili'ty of the Tier I CO limit.
Comments should include supporting a
documentation opdata on any of the
above issuers,, including inf ormation
demonstrating how the device is
designed and operated to achieve high.
combustion efficiency but nonetheless
has CO levels exceeding 100 ppmv.
Low flue gas CO concentration is
widely used as an indicator of "good
combustion practices'" for waste-to-
energy systems. Combustion of . '
municipal waste and refuse derived fuel
(RDF) in modern design; municipal waste
combustors (MWCs) requires sufficient
oxygen and mixing at uniformly high
furance temperature to ensure complete
combustion of toxic organics,, including
pplychlorinated dibenzo-p-dioxins and
furans (PCDB/PCDF). Although/by most
technical accounts, CO is not considered
directly relatable to PCDD/PCDF
emissions from MWCs,, the Agency has
recently proposed to. limit CO level's
from MWCi! to; ensure high combustion
efficienty."6^ Limits, on CO combined
with other requirements are designed to
minimize emissions of PCDD/PCDF
emissions. The proposed MWC CO'
limits vary iirom 50 ppmv to 150 ppmv
depending on the type of device, and' are
calculated cm a 4-hr average basis, dry-
corrected to; 12 percent CO2. The limits
are technology-based—they represent
levels readily achievable by well-
designed and well-operated units. EPA
does not beliieve that the proposed limits
of 50 ppmv to 150 ppmv for MWCs
presents a conflict with today's
proposed 100 ppmv de minimis CO
.emission liniit for hazardous waste
incinera'tors. .The 100 ppmv limit
proposed in- today's rule for hazardous
waste incinerators can be waived to
allow higher CO levels provided that HC
levels to not exceed acceptable level's.
We did not propose to limit CO to a
level lower than 100 ppmvr although
readily achievable by many hazardous
waste incinerators, because available
data indicate that PIC emissions; do not
pose significant health; risk when the CO
concentraticmislOOppmv. ' :
' See 54 FR !>2251 (December 20; 1989).
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Federal Register / Vol. 55, No. 82J Friday, April 27, 1990 / Proposed Rules
E, Derivation of the Tier II Controls
If the highest hourly average GO level
during the trial burn exceeds the Tier I
limit of 100 ppmv, a higher CO level
would be allowed if emissions of
hydrocarbons (HC) are considered
acceptable under two alternative
approaches: a health-based approach, or
a technology-based approach. We prefer
the technology-based approach for
reasons discussed below. One of the
alternatives will be selected for the final
rule based on public comment and
Agency evaluation, including a critique
by the Agency's Science Advisory Board
(SAB).85
1. Health-Based Approach. Under the
health-based approach to waive the 100
ppmv CO limit, the applicant would be
allowed to demonstrate that PIC
emissions from the combustion device
pose an acceptable risk (i.e., less than
10"*88) to the maximum exposed
individual (MEI). Under this approach,
we would require the applicant to
quantify total hydrocarbon (THC)
emissions during the trial burn and to
assume that all hydrocarbons are
carcinogenic compounds with a unit risk
that 1 as been calculated based on
available data. The THC unit risk value
would be 1.0 x 10—5 ms/jag and
represents the adjusted, 95th percentile
weighted (i.e., by emission
concentration) average unit risk of all
the hydrocarbon emissions data in our
data base of field testing of boilers,
industrial furnaces, and incinerators
burning hazardous waste. The weighted
unit risk value for THC considers,
emissions data for carcinogenic PICs
(e.g., chlorinated dioxins andfurans,
benzene, chloroform, carbon
tetrachloride) as well as data for PICs
that are not suspected carcinogens and
ore considered to be relatively nontoxic
(e.g., methane, and other Ci as well as
Ci pure hydrocarbons, i.e., containing
only carbon and hydrogen). We adjusted
the data base as follows to increase the
conservatism of the calculated THC unit
risk value: (1) we assumed that the
carcinogen formaldehyde is emitted
from hazardous waste combustion
devices at the 95th percentile levels
found to be emitted from municipal
waste combustors; 8T and (2) we
" Report of the Products of Incomplete
Combustion Subcommittee, Science Advisory
Board, U.S. EPA. "Review of the Office of Solid
\Vttsto Proposed Controls for Hazardous Waste
Incinerator*: Products of Incomplete Combustion",
October 24.1939.
"In selecting • risk threshold of 10""for these
rules, EDA considered risk thresholds in the range
of 10"4lo 10-'. As discussed in section I.D. of Part
Three of tha text, the Agency requests comment on
oltcrrmtlvo risk thresholds.
** Because of Its extremely high volatility, special
t*»k sampling and analysis procedures are required
assumed that every carcinogenic
compound in appendix VIII of part 261
-for which we have health effects data
but no emissions data is actually
emitted at the level of detection of the
test methods, 0.1 ijg/1. Finally, we
assigned a unit risk of zero to
noncarcinogenic compounds (e.g., d-C2
hydrocarbons such as methane,
acetylene). The calculated unit risk
value for THC is 1 x 10~5 m3/|u,g,
comparable to the value for carbon
tetrachloride.68
To implement the health-based
approach with minimum burden on
permit writers and applicants, we have
established conservative THC emission
Screening Limits as a function of
effective stack height, terrain, and land
use. See Appendix B of the October 26,
1989, supplemental notice for boilers/
furnaces (54 FR 43739). These Screening
Limits were back-calculated from the
acceptable ambient level for THC, 1.0
jug/m3 (based on the unit risk value
discussed above and an acceptable MEI
risk of 10"5), using conservative
dispersion coefficients. (We also used
those dispersion coefficients to develop
alternative emissions and feed rate
limits for metajs and HCI, as discussed
elsewhere. The basis for those
dispersion coefficients is also discussed
elsewhere.) If THC emissions measured
during the trial burn do not exceed the
THC emissions Screening Limits, the risk
posed by THC emissions would be
considered acceptable. If the Screening
Limits are exceeded, the applicant
would be required to conduct site-
specific dispersion modeling using EPA's
"Guideline on Air Quality Models
(Revised)" to demonstrate that the-
(potential) MEI exposure level (i.e., the
maximum annual average ground level
concentration) does not exceed the
acceptable THC ambient level.
2. Technology-Based Approach. Under
this Tier n approach, the Tier I CO limit
of 100 ppmv would be waived if HC
levels in the stack gas do not exceed a
good operating practice-based limit of 20
ppmv.
We have developed this technology-
based approach because of concern
about current scientific limitations of the
risk-based approach. In addition, the
risk-based approach could allow THC
levels of several hundred ppmv—levels
that are clearly indicative of upset
combustion conditions.
to measure formaldehyde emissions. Such testing
has not been successfully conducted during EPA's
field testing of hazardous waste combustion
devices.
«» For additional technical support, see U.S. EPA,
"Background Information Document for the
Development of Regulations for PIC Emissions from
Hazardous Waste Incinerators," October 1989
(Draft Final Report).
The Agency believes that risk
assessment can and should be used to
limit the application of technology-
based controls—that is, to demonstrate
that additional technological controls,
even though available, may not be
needed. However, we are sufficiently
concerned that our proposed to THC
risk assessment methodology may have
limitations, particularly when applied to
THC emitted during poor combustion
conditions (i.e., situations where CO
exceeds 100 ppmv), that we are
considering a cap on HC emissions.
Although we believe the development of
risk-based approach is a positive step,
we are concerned whether the risk-
based approach is adequately protective
given our limited data base on PIC
emissions and understanding of what
fraction of organic emissions would be
detected by the HC monitoring system.
Notwithstanding the limitations of the
THC risk assessment methodology,
however, we believe it is reasonable to
use the methodology to predict whether
a technology-based limit appears to be
protective. We have used the risk
assessment methodology to show that a
20 ppmv HC limit appears to be
protective of public health.
We discuss below our concerns with
the proposed THC risk-based approach
and the basis for tenatively selecting 20
ppmv as the recommended HC limit
(measured with a conditioned gas
monitoring system, recorded on an
hourly average basis, reported as
propane, and corrected to 7% oxygen).
a. Concerns with the THC Risk
Assessment Methodology. Our primary
concern with.the risk assessment
methodology is that, although it may be
a reasonable approach for evaluating
PIC emissions under good combustion
conditions, it may not be adequate for
poor combustion conditions—when CO
exceeds 100 ppmv. The vast majority of
our data on the types and -
concentrations of PIC emissions from
incinerators, boilers, and industrial
furnaces burning hazardous waste were
obtained during test burns when the
devices were operated under good
combustion conditions. CO levels were
often below 50 ppmv. Under Tier II
applications, CO levels can be 500 to
10,000 ppmv or higher (there is no upper
limit on CO).69 The concern is that we
do not know whether the types and
concentrations of PICs at these elevated
CO levels, indicative of combustion
upset conditions, are similar to the types
and concentrations of PICs in our data ,
base. It could be hypotesized that as
•• Hazardous waste incenerators have operated
at CO levels exceeding 13,000 ppmv during trial
burns that achieved 99.9995 distributed and removal
efficiency.
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Federal Register / VoL; 55,, No.\82J.
combustion conditions deteriorate, the
ratio of semi-arid nonvolatile
compounds to volatile compounds may
increase. If so, this could have serious
impacts on the proposed risk
assessment methodology. First, the
proposed generic-unit risk value for THC
may be understated when applied to
THC emitted under poor combustion
conditions. This is because semi- and
nonvolatile compounds comprise only
1% of the mass of THC in our data base,
but pose 80% of the estimated cancer
risk* Thus, if the fraction of semi- and
nonvolatile compounds increases under
poor combustion conditions, the cancer
risk posed by the compounds may also '
increase.
To put this concern in perspective, we
note that the proposed THC risk value
calculated from available data is 1X
10~5 mS/fig. This unit risk is 100 times
greater (i.e., more potent) than the unit
risk for the quantified PICs with the
lowest unit risk (e.g.,
tetrachloroethylene), but 1000 times
lower than the risk for PICs such as
dibenzoanthracene, and 10,000 to
1,000,000 times lower than the unit risk
for various chlorinated dioxins and
furans.
Second, if the fraction of semi- and
nonvolatile THC increases under poor
combustion conditions, the fraction of
THC in the vapor phase when entering
the THC detector may be lower than the
75% assumed when operating under
good combustion conditions.70 If so, the
correction factor for the so-called
missing mass would be greater than the
1.33 factor proposed.
The Agency is currently conducting
emissions testing to improve the data
base in support of the proposed risk-
based approach. We are concerned,
however, that the testing that is
underway and planned may not provide
enough information to support the risk-
based approach. In particular, we are
concerned that pur stack sampling and
analysis procedures and our health
effects data base are not adequate to
satisfactorily characterize the health
effects posed by PICs emitted under
poor combustion conditions.
A final concern with the risk
assessment methodology is that it does
riot consider health impacts resulting
from indirect exposure. As explained
above, the risk-based standards .
proposed today consider human health
impacts only from direct inhalation.
Indirect exposure via uptake through the
70 See discussions in US EPA, "Background
Information Document for the Development of
Regulations for PIC Emissions from Hazardous
Waste Incine'rators," October 1989. (Draft Final
Report) • : '. ,
food chain, for example; has not been
considered because the Agency has not
yet developed site-specific procedures
for quantifying indirect exposure
impacts for purposes of establishing
regulatory emission limits.
b. Basis for the HC Limit. We request
comment on a HC limit of 20 ppmv as
representative of a HG level
distinguishing between good and poor
combustion conditions. Under this
alternative approach, HC would be
monitored continuously during the trial
burn, recorded on an hourly average
basis, reported as ppmv propane, and
corrected to 7% oxygen. (See discussion
below regarding performance
specifications of the HC monitoring
system.) We have tentatively selected a
level of 20 ppmv because: (1) it is within
the range of values reported in our data
base for hazardous waste incinerators
and boilers and industrial furnaces.
burning hazardous waste; and (2) the
level appears to be protective of human
health based on risk assessments using
the proposed methodology for 30
incinerators.71
The available data appear to indicate
that the majority of devices can meet a
HC limit of 2p ppmv when op'erating
under good conditions (i.e., when CO is
less than 100 ppmv). It appears, in fact,
that many hazardous waste incinerators
can typically achieve HC levels of 5 to
,10 ppmv when operating generally at
low CO levels. When incinerators emit
higher HC levels typically exceed 100
ppmv, indicative of poor combustion
conditions. As discussed in the October
28,1989, supplemental notice to the
boiler/furnace proposed rules, the
available information on boilers and
industrial furnaces is not quite as clear,
however. Athough the data base
indicates that boilers burning hazardous
waste can easily meet a HC limit of 20
ppmv, the Agency has obtained data on
various types of boilers burning various
types of fossil fuels (not hazardous
waste) that indicate that HC levels can
exceed 20 ppmv when CO levels are less
than 100 ppmv.-See footnote 70. We are
reviewing that data and obtaining
additional information to determine if "
an alternative limit may be more
appropriate for boilers. We specifically
request comment on whether a HG
concentration of 20 ppmy in fact
represents good operating practice for
boilers burning hazardous waste as the
sole fuel or in combination with other
fuels.
We also request comment on whether
a HC concentration of 20 ppmv
. 71 Memorandum from Shiva Garg, EPA, to the
Docket, entitled "Supporting Information for a GOP-
Based THC Limit", da ted October 20,1988. •-_-'•.
represents good operating practice for
industrial furnaces. Preheater and
precalciner cement kilns, for example,
may not be able to readily achieve such
a low HG concentration for the same
reason that they typically cannot
achieve GO levels below 100 ppmv. !
Normal raw materials such as limestone
can contain trace levels of organic
materials that oxidize incompletely as
the raw material mpves down the kiln
from the feed end to the hot end where
fuels are normally fired. Clearly, any HC
(or CO) resulting from this phenomenon
has nothing to do with combustion of
hazardous waste fuel. Thus, an-
incinerator and a preheater or
precalciner cement kiln with exactly the
same quality of combustion conditions
may have very different HC (and CO)
levels. We request comment on: (1) the
types of industrial furnaces for which a
HC level 20 ppimv is representative of
good combustion conditions; (2) whether
alternative HC limits may be more
appropriate for certain industrial
furnaces; and [3) whether an approach
to identify a site-specific HC limit
representative of good operating
practices may be feasible (e.g.; where
HG levels when burning hazardous
waste.would be limited to baseline HG
levels without burning hazardous
waste). In support of comments, we
request data on emissions of CO andHC
- under baseline! and hazardous waste
burning conditions, including
characterization of the type and
concentration of individual organic
compounds emitted.
As mentioneid previously, some data
on CO and HG levels from industrial
boilers burning fossil fuels (not
hazardous wasste) appear to indicate
that HC levels can far exceed levels
considered to be representative of good
combustion conditions (20 ppmv) even
though CO levels are less than 100
ppmv. See foolnote 70. If it appears that
this situation can, in fact, occur for
particular devices burning particular
fuels, we would consider requiring both
CO arid HC monitoring for all stich
facilities irrespiective of whether CO
levels were less than 100 ppmv during
the trial burn. Thus, under this scenario,
the two-tiered CO controls proposed
today would be replaced with a
'requirement to continuously monitor CO
and HC for those particular facilities.
We specifically request information on
the types of facilities where HC levels
may exceed 20 ppmv even though CO
levels are less than 100 ppmv, and the
need to continuously monitor, HC for '•.,''
those facilities irrespective of the CO
level achieved during the trial burn. _ :
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Federal Register / Vol. 55, No. 82 / 'Friday, April 27, 1990 /
F. Implementation of Tier I and Tier II
PIC Controls
1. Oxygen and Moisture Correction.
The CO limits for either format are on a
dry gas basis and corrected to 7 percent
oxygen. The oxygen correction
normalizes the CO data to a common
base, recognizing the variation among
the different technologies as well as
modes of operation using different
quantities of excess air. In-system
leakage, the size of the facility and the
type of waste feed are other factors that
cause oxygen concentration to vary
widely in Incinerator flue gases. Seven
percent oxygen was selected as the
reference oxygen level because it is in
the middle of the range of normal
oxygen levels for hazardous waste
incinerators and it also is the reference
level for the existing particulate
standard under § 284.343(c). The
correction for humidity normalizes the
CO data from the different types of CO
monitors (e.g., extractive vs. in situ). Our
evaluation indicates that the above two
corrections, when applied, could change
the measured CO levels by a factor of
two in some cases.
Measured CO levels should be
corrected continuously for the amount of
oxygen in the stack gas according to the
formula:
CO.-CO,. X
14
21-Y
where COe ia this corrected
concentration of CO in the stack gas,
COm is the measured CO concentration
according to guidelines specified in
Appendix C, and Y is the measured
oxygen concentration on a dry basis in
the stack Oxygen should be measured
at the same stack location that CO is
measured.
2. Formats of the CO Limit. The CO
limits under Tier I and Tier II would be
implemented under two alternative
formats, The applicant would select the
preferred approach on a case-by-case
basis. Under Format A, CO would be
measured and recorded as an hourly
rolling average. Under Format B, called
the time-above-a-limit format, three
parameters would be specified—a
never-to-be-exceeded CO limit, and a ,
base CO limit not to be exceeded for
more than a specified tune in each hour.
In developing these alternative
formats, EPA considered three
alternative methods:
• A level never to be exceeded;
• A level to be exceeded for an
accumulated specified time within a
determined time frame; and
• An average level over a specified
time that is never to be exceeded.
The first alternative is the simplest
and requires immediate shutdown of an
incinerator when the limit is exceeded,
regardless of how long the CO levels
remain high. Short-term CO excursions
or peaks (a few minutes duration) are
typical of incenerator operation and can
occur during routine operations; e.g.,
when a burner is adjusted. It is possible
that during shutdown and start-up, the
incinefa tor may momentarily have high
CO emissions. Since the total mass
emissions under such momentary CO
excursions is not high, a never-to-exceed
limit would impede incinerator
operation while providing little
reduction in health risk.
The second alternative, allowing the
CO level to exceed the limit for a
specified accumulative time within a
determined time frame (e.g., x minutes in
an hour), solves the problem associated
with the first alternative. Incinerators
would riot be shut down by a single CO
peak of high intensity yet they would be
restricted from operation with several
short interval CO peaks, or a single long
duration peak.
The third alternative, allowing the CO
level never to exceed an average level
determined over a specified time, also
avoids the problem of shutting off the
waste feed each time an instantaneous
CO peak occurs. A time-weighted
average value (i.e., integrated area.
under the CO peaks over a given time
period) also provides a direct
quantitative measure of mass emissions
of CO. For this reason, the use of a
rolling average is EPA's preferred
format. A combination of the first and
second alternatives, with provisions to
limit mass CO emissions per unit time, is
also proposed as an alternative format.
This alternative CO format has been
proposed to reduce the cost of
instrumentation from that required to
provide continuous rolling average CO
values corrected for oxygen. This format
may be particularly attractive to
operators of small or intermittently
operated incinerators. The CO
monitoring system needed for the first
alternative requires continuous
measurement and adjustment of the
oxygen correction factor and continuous
computation of hourly rolling averages.
The instrumentation costs of such a
system, consisting of .continuous CO and
oxygen monitors with back-up systems,
a data logger and microprocessor, could
be up to $91,000 and would require
increased sophistication and operating
costs over simpler systems. The only
instrumentation needed for the
alternative time-abpve-the-limit format
is a CO monitor and a timer that can
indicate cumulative time of exceedances
in every clock hour, at the end of which
it is recalibrated (manually or
electronically) to restart afresh. Oxygen
also would-not have to be measured
continuously in this format; instead, an
oxygen correction value can be
determined from operating data
collected during the trial bum.
Subsequently, oxygen- correction values
would be determined annually or at
more frequent intervals specified in the
facility permit.7 2 We have riot limited
the use of this alternative CO format to
any size or to any type or class of
incinerators since we consider that this
alternative format provides an equal
degree of control of CO emissions to the
rolling average format.
The alternative format would require
dual CO levels to be established by the
permit writer, the first as a never to
exceed limit and the second a lower
limit for cumulative exceedances of no
more than a specified time in an hour.
These limits and the time duration of
exceedance shall be established on a
case-by-case basis by equating the mass
emissions (peak areas) in both the
formats so that the regulation is equally
stringent in both cases. The Background
Document73 provides the methodology
and mathematical formulae showing
how this can be done.
3. Monitoring CO and Oxygen.
Compliance with the Tier I CO limit
would require: (1) continuous monitoring
of CO during the trial burn and after the
facility is permitted; (2) continuous
monitoring of oxygen during the trial
burn and, under the 60-minute rolling
average format, after the facility is
permitted; and (3) measurement of
moisture during the trial burn and
annually (or as specified in the permit)
thereafter. Compliance with the Tier II
CO limits would require all the Tier I
measurements and measurement of HC
during the trial burn. Methods for
measurements of CO and pxygen, (and
THC) must be in accordance with the
3rd edition of SW--846, as amended. The
methods are summarized in appendix C
of the October 26,1989, boiler/furnace
supplemental notice (see 54 FR 43739-
45), and are discussed in more detail in
"Proposed Methods for Stack Emissions
71 We believe that annual determinations of the
oxygen correction factor will be appropriate in most
cases because the concern is whether duct in-
leakage has substantially changed over time. The
fact that excess oxygen levels also change with
waste type and feed rate should be considered in
establishing the correction factor initially.
"US EPA, "Background Information Document
for the Development of Regulations for PIC
Emissions from Hazardous Waste Incinerators,"
October 19B9 (Draft Final Report).
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than & limit of 20 ppmv is needed to
adequately protect public health.
The HC monitoring method proposed
in appendix D of the boiler/furnace
supplemental notice (54 FR 43743) will
be modified to allow an unheated,
conditioned system and uoe of
condensate trap(s) and other
conditioning methods. Performance
specifications for the gas conditioning
system would be discussed above.
5. Compliance with Tier I CO Limit,
There are a number of alternative
approaches to evaluate CO readings
during the trial burn to determine
compliance with the 100 ppmv limit
Including: (1) the time-weighted average
CO level (or the average of the hourly
rolling averages); (2) the average of the
highest hourly rolling averages for all
trial burn runs; or (3) the higliest hourly
rolling average. The time-weighted
average alternative provides the lowest
CO level that could reasonably be used
to determine compliance, and the
highest hourly rolling average
alternative provides the highest CO
level that could reasonably be used.
There may be other reasonable
alternatives between these two
extremes in addition to the one listed
above.
We are proposing to use the most
conservative approach to interpret trial
burn CO emissions for compliance wtih
the 100 ppmv Tier 1 limit—the highest
hourly rolling average. (This approach is
conservative because we are comparing
the trial bum CO level to the maximum
CO allowed under Tier I—100 ppmv.)
We believe this conservative approach
is reasonable given that compliance
with Tier I allows the applicant to avoid
the Tier II requirement to evaluate HC
emissions to provide the additional
assurance (or confirmation) that HC
emissions do not exceed levels
representative of good operating
practice.
6. Establishing Permit Limits for CO
under Tier II. The alternatives discussed
above for interpreting CO trial burn data
also apply to specifying the permit limit
for CO under Tier IL For purposes of
specifying a Tier EL CO limit, however,
the time-weighted average approach
would be more conservative than the
highest hourly average approach
because it would result in a lower CO
limit. We are proposing the
conservative, time-weighted average
approach for Tier n compliance because
we are concerned that the highest hourly
average approach may not be
adequately protective. Although the
highest hourly average (HHA) approach
would be protective in theory because
the applicant must demonstrate that the
highest hourly average HC emissions do
not exceed good operating practice-
based levels, the HHA approach would
allow the facility to operate
continuously over the life of the permit
at the highest CO levels that occurred
during one hour of the trial burn.
We specifically request comments on
how to interpret trial burn CO data to
establish Tier II CO limits.
7. Compliance with HC Limit of 20
ppmv. The alternative approaches for
determining compliance with the 20
ppmv HC limit under Tier II are
identical to those discussed above for
compliance with the Tier I CO limit.
Again, we are proposing the most
conservative approach—the highest
hourly rolling average HC level during
the (at a minimum) three test bums must
not exceed 20 ppmv.
8. Waste Feed Cutoff Requirements.
Today's proposal would .require cutoff of
the waste feed if the CO limit is
exceeded. In addition, we are requesting
comment on requiring continuous
monitoring of HC. If continuous
monitoring of HC is required, cut off of
the waste feed would also be required if
the HC limit is exceeded.
The regulations proposed today
require that minimum permitted
combustion temperatures be maintained
after waste feed cutoff for the duration
that the wastes remain in the
combustion chamber. To comply with
this requirement, the permit must
specify the minimum combustion
chamber temperature occurring during
the trial burn for devices that may leave
a waste residue in the combustion
chamber after waste feed cutoff (e.g.,
devices burning wastes that are solids).
We believe that PIC emissions from
"smoldering" waste remaining in the
combustion chamber should not pose
unacceptable health risks provided that
system temperatures are maintained.
An uninterruptible auxiliary burner of
adequate capacity may be needed to
maintain the temperature in the
combustion chamber(s) and allow
destruction of the waste materials and
associated combustion gases left in the
incineration system after the waste feed
is cutoff due to an upset. The safe start-
up of the burners using auxiliary fuel
require approved burner safety
management systems for prepurge, post-
purge, pilot lights and induced draft fan
starts. If these safety requirements
preclude immediate start-up of auxiliary
fuel burners and such start-up is needed
to maintain temperatures (i.e., if the
combustion chamber temperatures drop
precipitously after waste feed is cut-off),
the-auxiliary fuel may have to be burned
continuously on low fire during non-
upset conditions. After cutoff, hazardous
waste may not be used as auxiliary fuel
unless the waste is exempt under
existing § 264.340 (b) or (c) from the
emissions standards because the waste
is ignitable, corrosive, or reactive and
contains insignificant levels of toxic
constituents.
There is some concern that this
requirement to maintain temperature ir»
the combustion chamber after a waste
feed cutoff may not be feasible in all
cases (e.g., where the burner cannot be
maintained in close proximity to the
combustible vapor generation point
because of an explosion hazard). EPA
specifically requests comments on this
issue, and what alternate approach
should be used to reduce the possibility
of PIG emissions from waste remaining
in the chamber after a waste feed cutoff.
We request comment on several
alternative approaches to allow restart
of the waste feed: (1) restart after the
hourly rolling average no longer exceeds
the permit limit; (2) restart after an
arbitrary 10 minute time period to
enable the operator to stabilize
combustion conditions; or (3) restart
after the instantaneous CO level meets
the hourly rolling average limit. This
third alternative (i.e., basing restarts on
the instantaneous CO1 levels) may be
appropriate because it may take quite a
while for the hourly rolling average to
come within the permit limit while the
event that caused the exceedance may
well be over even before the CO monitor
reports the exceedance. Under this
alternative, the rolling average could be
"re-set" when the hazardous waste feed
is restarted either by: (1) basing the
hourly rolling average on the CO level
for the first minute after the restart (the
same approach that would be used any
time the waste feed is restarted for
reasons other than a CO exceedance); or
(2) assuming more conservatively given
that CO levels may exceed the permit
limit after the waste feed cutoff while
residues continue to burn, that the
hourly rolling average is equivalent to
the permit limit (e.g., 100 ppmv) prior to
the waste feed restart. A final
refinement to 'this third alternative of
allowing restarts after instantaneous CO
levels fall below the permit limit would
be not to reset the rolling average CO
level and to require that the
instantaneous CO level not exceed the
(rolling average) permit limit (e.g., 100
ppmv) for the period after the restart
and until the rolling average falls below
the permit limit.'Again,'we specifically
request comment on these alternative
approaches to allow waste feed restarts.
When the automatic waste feed cutoff
is triggered by a HC exceedance (i.e., if
the final rule limits HC levels beyond ,
the trial burn and requires continuous
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Federal Register /Vol. 55, No. 82 /; Friday. April 27, 1990 / Proposed Rules 17889
HC monitoring), we propose to allow a
restart only after the hourly rolling
average HC level has been reduced to 20
ppmv or less. We are not considering
the options discussed above for restarts
after a CO exceedance given that HG is
a better surrogate for toxic organic
emissions than CO. Thus, we believe
that a more conservative waste feed
restart policy is appropriate after a HC
exceedance.
.G. Request for Comment on Limiting
APCD Inlet Temperatures
We are requesting comment on
whether to limit!the temperature of
stack gas entering a dry emissions
control device (e.g., bag house,
electrostatic precipitator (ESP)} to
minimize formation of chlorinated
dibenzodioxin arid dibenzofurans (CDD/
CDF). The same discussion is presented
above in the section requesting comment
on additional regulatory issues
pertaining to boilers and industrial
furnaces burning hazardous waste.
After conducting extensive emissions
testing of municipal waste combustors
(MWCs), the Agency has concluded that
CDD/GDF can form on MWC flyash in
the presence of excess oxygen at
temperatures in the range of 480 to 750
°F.82 Cooling the flue gases and •:
operating the air poUution control device
(APCD) at temperatures below 450 °F
helps minimize the formation of CDD/
CDF in the flue gas. Thus, the Agency
has recently proposed to limit MWC
stack gas temperatures at the inlet to the
APCD to 450 °F. See 54 FR 52251
(December 20,1989).
Given that some hazardous waste
incinerators and boilers and industrial
furnaces burning hazardous waste are
equipped with dry particulate control
devices, we request comment on the
need to control gas temperatures to 450
°F to minimize CDD/CDF formation.
Although available data indicate that :
CDD/CDF emissions from hazardous
waste combustion devices are much
lower than can be emitted from
MWCs,83 it may be prudent to limit
82 See US EPA, "Municipal Waste Combustion
Study: Combustion Control of Organic Emissions",
EPA/530-SW-87-021C, NTIS Order No. PB87-
206090, US EPA, "Municipal Waste Combustion
Study: Flue Gas Cleaning Technology", EPA/530-.
SW-87-O21D, NTIS Order No. PB87-206108, and 54
FR 52251 (December 20,1989).
?3 See discussions in US EPA, "Background
Information Document for the Development of
Regulations for PIC Emissions from Hazardous
Waste Incinerators", October 1989. (Draft Final
Report), and Engineering Sciences, "Background
Information Document for the Development of
••Regulations to Control the jfurning of Hazardous
Waste in Boilers and Industrial Furnaces, Volume
HI: Risk Assessment", February" 1987. (Available
from the National Technical Information Service,
Springfield, VA, Order No. PB 87173845.)
temperatures in hazardous waste
combustion devices as well.
PART FOUR; PERMIT PROCEDURES AND
OTHER ISSUES "
I. impact on Existing Permits •
Upon promulgation of today's
proposed rule, EPA will use its authority
to reopen existing permits to include .
conditions necessary to comply with
these rales.'This authority is found in 40
CFR 270.41(a)(3) (see 52 FR 45799 -
(December 1,1987)), which allows EPA
to initiate modifications to a permit
without first receiving a request'from the
permittee; in cases where new
regulatory standards affect the basis of
the permit ,
In addition, permit writers will be
expected to continue to implement the
appropriate controls on metals, HC1, and
PIC emissions proposed here on a
permit-by-permit basis without waiting
for promulgation of the final rule.
Because many incinerators are
scheduled to be permitted in the interim
and due consideration of the risk posed
by metals, HC1, and PIC emissions is
needed, this caserspecific
implementation will ensure adequate
protection of public health. Permit
writers.can implement appropriate .. -
controls under the omnibus authority of
section 3005(c)(3) of HSWA and codified
at § 270.32(b)(2). The omnibus provision
gives the permit writer the authority to
establish permit conditions as necessary
to protect human health aiid the
environment. Like.the proposed rule, the
Agency's current guidance documents 8*
Screening Limits for metals and HC1 to
demonstrate that emissions are
acceptable, and if the Screening Limits
are exceeded, the applicant must
demonstrate by site-specific dispersion
modeling that emissions will not result
in exceedances of acceptable ambient
levels. The PIC guidance document also
uses the two-tiered approach proposed
m today's rule to limit CO and HC
concentrations in stack gas.
II. Waste Analysis Plans and Trial Burn
Procedures •
- The proposed metals controls will
impose added sampling and analyses
requirements at hazardous waste
incinerators burning wastes with levels
of metals that are likely to exceed
emission limits, or related metal feed
rates. EPA anticipates that existing
waste analysis plans, and trial burn
procedures at many, if not all, facilities
will need to be reviewed and modified.
A. Waste Analysis Plans ,•
Existing irules require the owner or
operator to conduct sufficient waste
analysis to'verify that waste feed to the
incinerator is within the physical and
chemical composition limits specified in
his permit (see § 264.341^)).
Compliance with the metals controls
will probably require many operators to
conduct additional analyses for
Appendix IRK metals, or to require the
generator of the waste to provide
information on the metal content of
waste sent to the incinerator. There
would be a requirement to keep records
of such analyses. To show compliance
with the feed rate limit requirements,
there would be a need for sampling of
blended wastes as fed to the incinerator,
or for recordkeeping to show, by ;
calculation, the amount of metals in
wastes thai: are blended. Comments on
the practicality- of compliance with
metals sampling, analysis, and
recordkeeping are requested.85
EPA's best determination of
appropriate metals sampling and
analyses procedures are given jn
Appendix A. Matrix effects have been
shown to be important in the analysis of
metals in oils and solids. Accordingly,
recommended sample preparation
methods are given in Appendix A.
Standardized protocols are not yet
widely available, but EPA's experience
indicates that published EPA Methods
for individual metals and particulate
matter work well. It is likely that any
protocol will require metal analysis of
waste feeds, residual streams (both
solid and liiijuid), and flue gas. Operators,
may wish to sample flue gas both before
and after air pollution control devices.
EPA's present rules allow the use of
equivalent methods of analyses upon a
showing of substantial scientific
validity. 1; ".'; : , "-•
B. Trial Burn Procedures ' -
All samples must be analyzed
according to the appropriate methods
specified in "Test Methods for
Evaluating Solid Wastes: Physical/
Chemical Methods," EPA publication
SW-846, as incorporated by reference in
40 CFR 260.11. Sampling for metals must
be done-using the Multiple Metals train
. summarized in Appendix A. The
Multiple Metals train and the methods
to monitor CO, HC1, and THC are
84 U.S. EPA, "Guidance on Metals and Hydrogen
Chloride Controls for Hazardous Waste
Incinerators," August 1989, and U.S. EPA,
"Guidance on PIC Controls for Hazardous Waste
Incinerators," April 1989. -
as ^ye npte that we have requested comment
earlier in the text on approaches other than waste
analysis combined with feed rate limits to
implement the controls on metals emissions. See
also 54 FR 43760 c.3. ~
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Federal Register / Vol. 55, No. 82 -';/ Friday, April 27, 1990 / Proposed Rules
discussed in more detail in "Proposed
Method! for Stack Emissions
Measurement of Carbon Monoxide,
Oxygen, Total Hydrocarbons, HC1, and
Metals at Hazardous Waste
Incinerators," as referenced above.
The analysis procedure consists of
two steps: Preparation (called digestion)
and the analysis itself. The digestion
process is dependent on both the
analysis procedure and the waste
matrix. Appendix A lists the digestion
methods and the proper analysis
technique and waate matrix of each one.
The analysis procedures are metal
specific. For some metals, tip to three
methods are applicable depending on
the precision of the detection limit
desired. See Appendix A for the proper
analysis methods to be used for each
metal. In some cases, the analysis
method includes its own digestion step
and the listed digestion methods are not
necessary.
Analysis for matrix effects
(interference) should be performed by
the Method of Standard Addition or
other appropriate procedures.
III. Emergency Release Stacks
EPA is clarifying today that no
emergeacy release stack openings are
allowed while hazardous waste is in the
incinerator unless the applicant has
demonstrated during the trial burn that
the performance standards of § 264.343
will be met while a dump stack is being
used. When such "dump" stacks are
used, combustion gases bypass the
emissions control equipment, and this
would cause violation of the permit
requirements to operate the control
equipment. Therefore, the use of
emergency release stack openings while
hazardous wastes remain in the
combustion chamber would be a
violation of the permit and subject to
enforcement action as deemed
appropriate by the Agency. During the
opening of a dump stack, emissions of
metals and HC1 could pose unacceptable
health risk. In addition, if temperatures
at the inlet to the dump stack are not
maintained at permit levels, HC
emissions could also pose substantial
health risk. While it is understood that
there can be mitigating circumstances
which require the use of emergency
relief stacks, these Instances should be
minimized. Under the Preparedness and
Prevention and Contingency Plan
requirements of Subparts C and D, the
applicant should address what they will
do to prevent the use of the dump stack
and the release of hazardous waste
constituents into the air, and what they
will do to minimize the hazard from
such releases (such as backup systems,
maintaining flame, temperature and
combustion air to combust organics).
See proposed | 270.62(b)(2)(vii).
IV. POHC Selection
One of the criteria for POHC selection
for demonstration of DRE is degree of
difficulty to incinerate the compound.
There are a number of "incinerability
indices" that could be used, but heat of
combustion has been considered by
many to be the best index currently
available. EPA studies 8S indicate,
however, that a ranking .based on
thermal stability under low oxygen
(substoichiometric) conditions may
correlate with field test data on DRE
better than heat of combustion. The
ranking was developed using lab-scale
reactors to determine the temperature
required to destroy 09 percent of a given
POHC in two seconds under
substoicbiometric (Va stoichiometric
oxygen) conditions. Mixtures of POHCs
were tested together to ensure that
adequate OH and H radicals were
available for compounds that undergo
biomoleculcar reactions. Modeling
indicates that thermal decomposition in
the flame gases is essentially complete.
Thus, any unburned POHCs are most
likely the result of small fractions of the
waste escaping flame temperatures by
several potential failure mechanisms
(e.g., poor atomization). Once in the
post-flame zone, the gas phase thermal
decomposition kinetics controls the rate
of POHC destruction. This would
explain why the low oxygen thermal
stability index (TSLoO2) which
simulates post-flame conditions,
appears to correlate better with field
test DRE data than heat of combustion,
autoignition temperature, and thermal
stability under excess oxygen
conditions.
Although the TSLoOz has not been
field validated, EPA believes it is a
promising approach to predicting the
relative stability of POHCs in the
combustion environment likely to result
in unbumed POHCs (and low DRE). The
TSLoOz index is presented in U.S. EPA,
"Guidance on Setting Permit Conditions
and Reporting Trial Burn Results:
Volume H of Hazardous Waste
Incineration Guidance Series", EPA/
625/6-59/019, January 1989. Thermal
stability values have been determined
by actual testing for approximately 80
Appendix VIII compounds. These
thermal stability values have been used
to predict the thermal stability values
for the remaining Appendix VIII organic
compounds based on assumed reactions
80 Tayloii P., and DelHnger, R., "Development of a
Thermal Stability Based Judex of Hazardous Waste
Incinerability", UDRIFY 88 Status Report for CR
813938, November 1988.
considering structural relationships of
the compounds. . •. .
We note that some compounds that
rank high on the heat of combustion
index rank do not rank high on the
TSLoOz. For example, carbon
tetrachloride ranks very high on the heat
of combustion index but near the middle
of the TSLoO2. Given the current
uncertainty about which index better
represents incinerability, we recommend
that the permit writer and applicant
consider the TSLoOa as well as other
indices when selecting POHCs and
identifying compounds in the permit that
an incinerator is allowed to bum. In
fact, the TSLoOz index has been
available to permit 'writers for over a
year. Many permit writers have used the
index to help select POHCs for trial
burns needed to support permits issued
by the RCRA-mandated deadline of
November 1989 for existing facilities.
The Agency is continuing to validate
the TSLoO2 and to address other
questions (e.g., are there sampling and
analysis procedures for those
compounds high on the TSLoOz) and
hopes to be able to be more definitive
about a preferred index when today's
proposed rule is promulgated. We
specifically request comment on the use
of the TSLoOa index for the purpose of
POHC selection.
V. POHC Surrogates
A number of lab scale, pilot scale, and
field tests have investigated the use of
nontoxic tracer surrogates (one example
is sulfur hexafluoride (SF6)) for POHCs
selected from appendix VIII of part 261.
Sulfur hexafluoride, in particular, shows
promise as a conservative tracer
surrogate. It is readily available
commercially, inexpensive, and
nontoxic. Appendix VIII POHCs,
especially when spiking is required to
increase concentrations in the waste for
DRE testing, are often difficult to obtain,
expensive, and a health hazard to
operators.' Sampling and analysis
techniques for SFe are well documented
because it has been used for years as a
tracer for monitoring ambient air.
Sampling techniques for appendix VIII
compounds (i.e., VOST and MM5) are
complicated, expensive, and even for
those with years of experience, prove to
produce substantial numbers of
measurements that do not meet QA/QC
standards.
Given the substantial benefits of using
SFe as a tracer compound; the Agency is
conducting additional testing and
analysis to answer remaining questions.
For example, the DRE of SFe has been
correlated to the DRE of only a few
appendix VIII compounds, and
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17891
sometimes, under conditions that may
not be representative _of typical
incineration operations. In addition,
standard procedures are needed for
feeding and stack sampling the tracer.
The Agency hopes to be able to publish
a Notice of Data Availability in the
Federal Register later this year to
present the results of the testing and to
propose categorically that SFe is an
acceptable surrogate for appendix VIE
POHCs. Ideally, the proposal would be
promulgated with the rest of today's
proposal.
We note that we are proposing today
to revise § 264.342(b}(l) and § 270.62
. (fa)(4), (b)(4)(i), and (b)(4)(ii) to delete the
requirement that a POHC must be listed
.in Appendix VIH. We are proposing this ;
change now to give permit writers and
- applicants the option of using nontoxic
tracers for DRB testing where the
applicant provides sufficient data to
demonstrate that the tracer is an
adequate surrogate. - ' ""
We specifically request information
pertaining to the use of SF6 and other
nontoxic tracer compounds as POHC
surrogates.
VI. Information Requirements
, Information requirements may be
imposed on a case-by-case basis
depending upon the complexity of risk
analysis and dispersion analysis needed,
at a particular location. The added
burden will be significantly increased
over existing part B requirements only
for facilities iri unusually complex
~ terrain situations or where .
representative meterological data are
not available. All facilities intending to
combust hazardous waste with amounts
• of metals that may exceed emission
limits will be required to submit
information needed for determining the
terrain and urban/rural classification of
the facility, Because.the determination is
based in part on using the concept of
terrain-adjusted effective stack height,
site specific parameters will be needed
for all sites. Information needs are
outlined below.
If available meterological data are not
considered representative of the site, a
screening model that does not require
the use of site-specific meterological
. data cam be used. We have developed a
screening model that jnay be
appropriate in such situations. See
appendix V of the "Guidance on Metals
and Hydrogen Chloride Controls for
Hazardous Waste Incinerators." We
note, however, that a screening model
that does not use site-specific
meterological data is designed to be
more conservative (i.e., predict higher
. ambient concentrations) than a
"regulatory" model recommended by
EPA's "Guideline on Air Quality Models
(Revised)". /
Reference information needed
includes facility name, address,
telephone number, and the number of
hazardous waste combustion sources on
site. Site information includes stack
parameters and terrain parameters. The
stack parameters consist of physical
stack height, exhaust temperaturre,
inner stack diameter, exit velocity, flow
rate, latitude/longitude or UTM
coordinates. Terrain parameters consist
of maximum terrain rise (in meters for
three distance ranges, 0-0.5 km, and 0-5
km), and shortest distance to fenceline.
Waste firing information needed
includes stack release identifications by
; incinerator, a number of incinerators,
maximum waste feed rate by input _
location (nozzle, lance, ram, etc.), and
metal feed rate for liquid wastes, solid
wastes, and organometals. Additional
parameters needed are the dimensions
for all buildings within 5 building
heights or the maximum projected
building width of the stack. For these
buildings, the following data are needed;
the distance from the stack, distance
from the nearest fenceline, building
height, building length,'and building
width. .:" . :
EPA requests comment on the
recordkeeping and reporting burden
associated with these information
requirements. : ,'_
VH. Miscellaneous Issues
EPA today proposes to amend
§ 264.345(a) to clarify that the
incinerator must operate in accordance
with the operating requirements
specified in the permit whenever there is
hazardous waste in the incinerator.
In addition, we propose to amend
§ 270.62(b)(8) to require that all data
collected during any trial burn must be
submitted within 90 days of completion
of trial burn. This requirement is to
ensure timely submission of trial burn
data. Section 270.62(b)(10) would be
revised to require that three runs must
be passed for each set of permit
conditions. This is to clarify that the
runs are not to be averaged, but must be
passed each time for all standards.
Section 270.62(b)(10j does allow for one
. of the three rims to be disregarded if the
Director believes there is sufficient ,
reason. EPA's criteria for disregarding a
run are discussed in U.S. EPA,
"Guidance on Setting Permit Conditions
and Reporting Trial Burn Results:
Volume II of Hazardous Waste
Incineration Guidance Series", EPA/
625/6-89/019, January 1989.
EPA today clarifies § 264.340(c) which
provides an exemption from all
requirements other than waste analysis
and closure for ignitable, corrosive or
reactive waste containing insignificant
concentrations of the hazardous
constituents listed in appendix VHI, part
281. In the past, this has been
interpreted! to mean organics in
appendix VIE, Now that EPA is
proposing to control metals emissions
and has a method to determine risks
from metals, metals in appendix VIII
should also be considered when
granting this exemption. Insignificant
concentrations can be taken from the
feed rate screening levels that would be
used to implement the metals controls.
See appendix D of the October 26,1989,
boiler/furnace supplemental notice.
Further, it is possible for a waste to be
exempted for one type of appendix Wl
constituent and not the other. For
example, if the waste contains -''.".
insignificant concentrations of metals
but significant concentrations of '
organics, then the waste could be
exempt from the requirement for metals,
but not for organics (e.g., DRE, CO/HC
limits), -'-:'•..'
Finally, we propose to note minor
-revisions tci the following sections to
conform with today's proposed controls:
Specific-part B information requirements
f0™^0^.?70-*9^). MMCiii),
(ii), (e), (f);
Hazardous waste incinerator permits
§ 270.62 (b)|[2)(i)(c), (b}(2)(i)(D),
), (c), .
All of today's proposed amendments
would be effective immediately upon
promulgation of the final rule. Given
that we beli eye that all of the
substantive provisions are necessary to
adequately protect public health and the,
environment and will, thus, be subject to
implementation under the omnibus
provision during the permitting process
before promulgation, applicants should
have ample tune to comply. For
example, permits under development
when the final rule-is promulgated
should alreaidy incorporate the new
controls .under the omnibus provision.
Vin. Halogen Acid Furnaces .
In the May 6, 1987, proposed rule (52
FR 17018-9), EPA proposed to add
halogen acid furnaces (HAFs) to the list
of industrial furnaces under § 260.10. We
are today requesting comment on
revisions we are considering to the HAF
definition, and proposing under
§ 261.2(d) to list inherently waste-like
materials that are fed to a HAF as
.hazardous waste,
HAFs burn halogenated secondary
materials aa an ingredient to produce .
halogen acid product, EPA proposed to
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Federal Register / Vol. 55. No. 82 /' JPriday,April 27,
Hit HAFs as industrial furnaces for
reasons discussed in the May 6,1S87,
proposal. To ensure that the device was
involved in bonafide production of acid
as an integral component of a
manufacturing process, the proposed
definition required that: (1) The furnace
mutt I-? located on-site at a chemical
prodiKiioa facility; (2) the waste feed
must be halogenated; and (3) the acid
product must have at least 6% acid
content, Based on comments on the
proposal and further consideration by
the Agency, we are considering revising
the definition to better distinguish
between 1 CAFs and halogenated waste
Incinerators equipped with wet
scrubbers to control halogen acid
emissions and to better reflect industry
practice.
To ensure that the device is an
integral component of a chemical
manufacturing process, we have
proposed that a substantial fraction of
the acid product be used on-site. Thus,
we would add to the definition that at
least 50% of the acid product be used on-
site. In addition, we would require that
any off-site waste fed to the HAF must
be indigenous to the chemical
production industry. Thus, the waste
must be generated by a SIC 281
(inorganic chemicals) or SIC 286
(organic chemicals) process.
To ensure that the waste is burned as
a bonafide ingredient to produce a
halogen acid product, we would require
that any waste fed to the HAF must
have an as-generated halogen content of
at least 20%.
To better reflect industry practice, we
would require that the acid product have
an halogen acid content of 3% rather
than 6%. We believe that this would still
dearly distinguish an incinerator
halogen acid scrubber water from the
acid product of an HAF because
incinerator scrubber water has an acid
content well below 1%.
Finally, we are proposing pursuant to
S 261,2(dX2} to list hazardous waste fed
to a HAF as inherently waste-like
material. Materials fed to the HAFs are
usually the residual still bottoms no
longer suitable for use as feedstock to
make new chemical products. Many are
listed wastes, for example the
genetically listed F024. These materials
contain dozens of appendix vm
constituents not ordinarily found in the
raw materials that are normally used to
produce chlorine. See the various listing
background documents for the listed
wastes from chlorinated organic
production, as well as appendix VII of
part 261 for these listings. Other than for
their chlorine content, these organic
toxicants do not contribute to
hydrochloric acid production; they are
destroyed (assuming the HAF operates
efficiently). Thus, these toxicants (which
by volume comprise the greater part of
these wastes) are discarded by thermal
combustion. Second, inefficient
combustion of the halogenated organic
compounds in wastes fed to a HAF can
pose the same risks to human health and
the environment as combustion of those
wastes in an incinerator, boiler, or other
industrial furnace. We thus believe that
the hazardous materials burned in these
devices are inherently wastelike.
We note, that to the best of EPA's
knowledge, all of these materials are
presently regulated as hazardous
wastes, because the devices in which
they are burned are either classified as
incinerators or burn partially for energy
recovery. Given, however, that the
wastes are used as an ingredient to
produce the acid product, the HAF
would not be subject to regulation if the
wastes were not burned partially for
energy (or materials) recovery.
Halogenated wastes with a heating
value of less than 5,000 Btu/lb could be
considered to be burned solely as an
ingredient in a HAF. Thus, we propose
to list as inherently wastelike material
any secondary material that is identified
or exhibits a characteristc of a
hazardous waste provided in subparts C
or D of part 261. See proposed
§261.2(d)(2).
PART FIVE: ADMINISTRATIVE, ECONOMIC
AND ENVIRONMENTAL IMPACTS
I. State Authority
A. Applicability of Rules in Authorized
States
Under section 3006 of RCRA, EPA
may authorize qualified States to
administer and enforce the RCRA
program within the State. (See 40 CFR
part 271 for the standards and
requirements for authorization.)
Following authorization, EPA retains
enforcement authority under sections
3008, 7003, and 3013 of RCRA, although
authorized States have primary
enforcement responsibility.
Prior to the Hazardous and Solid
Waste Amendments of 1984 (HSWA), a
State with final authorization
administered its hazardous waste
program entirely in lieu of EPA
administering the Federal program in
that State. The Federal requirements no
longer applied in the authorized State,
and EPA could not Issue permits for any
facilities in the State which the State
was authorized to permit. When new,
more stringent Federal requirements
were promulgated or enacted, the State
was obliged to enact equivalent
authority within specified time frames.
New Federal requirements did not take
effect in an authorised State until the
State adopted the requirements as State :
law.
In contrast, under section 3006(g) of
RCRA, 42 U.S.C. 6926(g), new
requirements and prohibitions imposed
by HSWA take effect in authorized
States at the same time that, they take
effect in nonauthorized States. EPA is
directed to carry out those requirements
and prohibitions in authorized States,
including the issuance of permits, until
the State is granted authorization to do
so. While States must still adopt
HSWA-related provisions as State law
to achieve or retain final authorization,
the HSWA applies in authorized States
in the interim.
Today's rule is proposed pursuant to
sections 3004 and 3005 of RCRA. Thus,
as ajnon-HSWA rule, it is not effective
in authorized States until such time as
the State is authorized to implement
them. However, the EPA has authority
under section 3005(c)(3), the HSWA
omnibus provision codifed at 40 CFR
270.32(b)(2), to impose any permit
condition deemed necessary to protect
human health and the environment. This
provision can be invoked whenever a
federal RCRA permit is issued (including
federal permits implementing HSWA
provisions that are issued concurrently .
with permits issued by an authorized
State for the same unit). Thus, all federal
permits—including those incorporating
the HSWA corrective action
requirements—could include conditions
based on EPA's omnibus authority. The
EPA has decided that the requirements
in today's rule relate to permit
conditions deemed necessary to protect
human health and lie environment and
that such conditions are needed for all
future permits to minimize risks from
toxic emissions of PICs, metals, and acid
gases. So, until such time as the
authorized States are able to impose
these new requirements in permits they
issue, EPA can impose them under the
direct authority of § 270.32(b)(2) in
authorized and unauthorized States,
effective the date of promulgation of this
rule, whenever a Federal RCRA permit
(or Federal portion of a RCRA permit) is
issued with respect to the facility. Prior
to the effective date of these regulations,
permit writers may impose these same
conditions (or others) at their discretion,
in Federal permits pursuant to the same
authority. (See part Four, I. Impact on
Existing Permits. The metals/HCl and
PIC guidance documents can be used to
implement these requirements prior to
promulgation of the rale).
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Federal -Register .'/"VoL 55,'No. 82 / Friday, April 27, 1990 / ^Proposed Rules 17S@3
&aKLSaS3aaS533^^%l&tWa^h^57^?3rrcl^^air^^E3iJ^^ .T»-j^ff^T^..^l^yiftff^u^1.~:.rT.^
5. Effect on State Authorizations
As noted above, today's rule proposes
standards that would be effective via
omnibus authority in all States
regardless of their authorization status.
Nonetheless, the authorized States must
also revise their program and adopt
equivalent requirements under their
State law by the deadlines set forth in
§270.21(e). "
Section 271.21(e)(2) requires that , ~
States that have final authorization must
modify their programs to reflect Federal
program changes and must subsequently
submit the modifications to EPA for.
approval. The deadline by which the
State must modify its program to adopt
this proposed regulation will be
determined by the date of promulgation
of the final rule in accordance with .
§ 271.21(e). These deadlines can be, .
extended in certain cases (40 !CFR
271.21(e) (3J). Once EPA approves the
modifications, the State requirements
become subtitle Cv RCRA requirements.
States with authorized RCRA
programs may already have
requirements similar to those in today's
rule. These State regulations have not
been assessed against the Federal
regulations being proposed today to
determine whether they meet the tests
for authorization. Thus, a State is not
authorized to carry out these
requirements in lieu of EPA until the
: State program modification is submitted
to EPA and approved. Of course, States
with existing standards may continue to
'administer and enforce their standards
a's a matter of State law. In fact, EPA
encourages States with similar
standards or with, their own omnibus
authority to impose these new
requirements as soon as possible.
States that submit their official
application for final authorization less
than 12 months after the effective date
of these s tandards are not required to,
include standards equivalent to these .
standards in their application. However
the State must modify its program by the
deadlines set forth in § 271.21(ej. States
that submit official applications for final
authorization 12 months or more after
the effective date of those standards
must include standards equivalent to
these standards in their application.
Section 271.3 sets forth the requirements
a State must meet when submitting its
final authorization application.
H. Regulatory Impact Analysis >
A. Purpose and Scope
EPA has determined that today's '."•
proposed rule is not a major rule as
defined by Executive Order 12291. This
section of the preamble discusses the
results of the cost impacts and risk
analyses of the -proposed rule. SPA has
also assessed small business impacts
resulting from the proposed rule, as
required under the Regulatory Flexibility
Act. , - "", ' .
The costing analysis and risk
assessment were constrained by data
availability. The major limitations that
should be considered when reviewing
the results are summarized below: '• ••
' * The main focus of the Regulatory
Impact Analysis (RIA) was the analysis
of the proposed 1X10~S ^7 risk standard; -
however, a less detailed analysis of an
alternative (1X10~^J deminimis risk
standard was also performed.'
». Because of data limitations, the RIA
evaluated only seven of the ten toxic
metals covered by today's proposed
.rule. Waste characterization data by
RCRA code could not be located for
thallium, antimony, and silver. .-'.,'-
• At this time, EPA was unable to :
complete a detailed analysis of the
chlorine content in diffemt wastes
currently being incinerated. As a
• surrogate, EPA calculated an average
, chlorine concentration in all hazardous
waste combusted using available test
•burn"data.-•-••• --:••-. .•--.--•
• The RIA estimated only the
incremental costs of the proposed CO
monitoring that includes a continuous
oxygen moriitof and a data-logger for
continuous oxygen corrections. Because
of time and resource constraints, the
analysis did not consider the proposed
alternative requirement (a CO monitor
and a timer) which could be less costly, .
• There was insufficient information
to quantify the potential human risks
posed by PICs or total residual ,
hydrocarbons at the present time.
• EPA did not perform an extensive
economic impact analysis. -A prelimary
estimate of economic impact was made
by completing a financial, ratio test.
B. Affected Population ,
Currently available information in
EPA's Hazardous Waste Data
Management System (HWDMS) lists 227
active hazardous waste incinerators
(approximately 207 noncommerciaLand
20,commercial) that will be subject to
the proposed requirements.88 Tnese
incinerators are widely dispersed
throughout the country (41 states plus
Puerto Rico). Texas has the most. :
incinerators with!27 facilities (12 .
percent), followed by Louisiana and ^
Ohio,- each with 17 facilities (7 percent),
87 In selecting a risk threshold of 10" 5 for these
rules,. EPA considered risk thresholds in the range of
1(T4 to 1CT6. As discussed in section I.D. of part
three of the text, the Agency requests comment on
, alternative risk thresholds. -_
88 USEPA, HWDMS, Version 6.5, October 9,1987.
and California wife IS facilities (7
percentj. Thirty-eight states, each with
between. 1 and 12 incinerators, together
account for 87 percent of the total.
Information on;the characteristics of
each incinerator (e.g., type of combustor,
existing air pollution controls, and
description of the type and quantity of
waste combusted) was not readily
.available; As a result, EPA relied on,
data reported in the 1982 Hazardous
Waste Incinerator Mail Survey, which
containis information (from 1981) on a
sample of 110 nbnconfidential facilities
comprising 152 units.88 The survey
responses for these incinerators were
examined for completeness regarding
necessary information and for deletion
of facilities no longer active. Based on
this evaluation, a subset of these
facilities—82 facilities (74 " •'-"'-
noncommercial and 8 commercial), 112
units—were selected as the sample
database for this analysis. The results of
the sample were then extrapolated to
the total population of 227 hazardous
waste incinerator sites (310 estimated
units). Implicit in the extrapolation is the
assumption that the distribution of
incinerators and waste characteristics
(e.g., number of units, type of combustor,
wastes combusted, current controls, and
stack delta) is the same in the sample as
it is in tlie.population. • "••
According to the Mail Survey data for
the 112 incine'rator units evaluated, most
hazardous waste Incinerators are liquid
injectors (54 percent). The remaining ...
incinerator units are, classified as
multiple chamber (12 percent), rotary
kiln (8 percent), controlled air (8
percent), and other (19 percent).
The Mail Survey data for the sample
facilities/units show that approximately"
42 percent of the hazardous waste
incinerators did not have air pollution -
control devices (APCDs) in place in - - •
,1981. Most of the remaining incinerator
units (48 percent) had treatment trains "
that included a wet scrubber. Very few
(approximately 29 percent) had other
technologies> such as electrostatic
precipitators (ESPs), venturi scrubbers,
-. and fabric filters, used to capture
particulates. v .
. The facilities evaluated fall into 40
different industrial categories, as
defined by the four-digit Standard
Industrial Classification (SIC) codes (see
table 4). Most industrial SIC codes
account for less than 2 percent of the
facilities.. The SICs with the largest '•'.' '..•
percentage fractions of hazardous waste
incinerators are: " '/-''•
89 The Mail.Survey also contains data for an
additional 15 confidential facilities [18 units), but
-this information was not used in this analysis.
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17894
Federal Register / Vol. 55, No. 82 / Friday, April 27, 1990 / Proposed Rules
* 2821 Plastics Material (10 percent).
• 2009 Industrial Organic Chemicals
flO percent),
* 4953 Refuse (Waste Management)
Systems (8 percent).
* 7391 Research and Development
Laboratories (7 percent).
• 2865 Cyclic Crudes and
Intermediates (5 percent).
* 2879 Agricultural Chemicals (5
percent).
An estimated 1.0 million kkg of
hazardous waste were combusted in
Incinerators in 1908.90 As shown in
Table 4, the majority of the waste
burned by hazardous waste incinerators
is concentrated in six industrial SIC
codes:
• 2819 Industrial Inorganic Chemicals
(48 percent).
* 2879 Agricultural Chemicals (13
percent).
• 2833 Medicinal Products (7 percent).
• 2885 Cyclic Crudes and
Intermediates (6 percent).
• 2869 Industrial Organic Chemicals
(6 percent).
• 2834 Pharmaceutical Preparations (5
percent).
The hazardous waste analyzed is
characterized by almost 60 different
RCRA codes. Two waste codes account
for the majority (71 percent) of
hazardous waste combusted: D001
(ignitable wastes) and X182 (a mixture
of U008—acrylic acid, U112—ethyl
acetate, U113—ethyl acrylate, and
POOS—acrolein). This analysis
determined that approximately 44
percent of the hazardous waste
combusted contains the metals of
concern for today's rule and roughly 37
percent of the hazardous waste contains
chlorine.
C. Costing Analysis
Today's rule proposes limits for
emissions of toxic metals, hydrogen
chloride (HC1), and carbon monoxide
(CO) as a means of controlling total
unbumed hydrocarbons (THCs) from.
hazardous waste incinerators. The
incremental costs of compliance can be
grouped into two major categories: costs
to demonstrate compliance with the
proposed standards and costs to reduce
emissions if a facility cannot show
compliance with the pollutant-specific
limits. The methodology and engineering
unit costs used by EPA to estimate the
incremental compliance costs
attributable to each of the three
standards are discussed below, followed
by a presentation of results. The costing
analysis was performed for the subset of
82 facilities selected from the Mail
Survey; results were extrapolated to the
population of 227 facilities.
As a sensitivity analysis, EPA also
completed a preliminary assessment of
the incremental compliance costs
associated with an alternative de
minimis cancer risk level of 1X10"6.
This section also presents the unit cost
estimates used in the sensitivity
analysis and the total predicted
• compliance costs under this alternative
scenario.
TABLE 4.—DJSTRIBUTION OF HAZARDOUS WASTE INCINERATORS AND HAZARDOUS WASTE COMBUSTED BY SIC
sic
Description
Facilities
No.
Percentage
Quantity of hazardous waste
combusted
(KKG/Year) Percentage
2231™™. Broad woven fabric mills
2282™™.. Yamtexturblng mills...™
2421 ™™. SawmSte and planing miils—
2491 ™.™ Wood prossrvSng
2511 ™™. Wocd household furniture.—
2681™™. BoWng paper/board milts.......
2813_..... Industrial gases
2319......... Industrial inorganic chem.
2S21™™. Ptestic material
2922™™. Synthetic rubber
2824.. Synthetic org. libers.™
2833™™. Medicinal products.
2334™.— Pharmaceut. preparations—
S84H™™. Perfumes/cosmetics
2S51 .. Pair.ts/aftd products™
2351—.-. Gum and wood chemicals....
2885™,™ Cystic crudes, org, pigments
2863.—... HxJ. oraarfc chemicals
2373™™. Nitrogenous fortSzers
2879—™ PesScktes/agrfc. chem.
2891 ™™. Adrtesives/saalants..™-—
28«™™. Exptoslves
2883™™. Chemical preparations
2911™™. Patrcfeum refining,
3078™. Mfec. pfaste....
3229™™. Pressed/blown g!a3s,.........
3339™-.™ Prim. smo!*ig nonferrous..
3412.,.,.,,, Metal shipping barrels, etc...
3433™-.. HMting equipment—
3.,6-3,....... Crowns and closures™—..
3483™™. AmmunfSon—.
3531™™. Construe, machinery equip.
3S72.™™ CaliKxJa ray TV tubes
3721....-.» Aircraft........
4853™™J Rofus« systems -.
3
3
3
3
6
3
3
8
22
3
6
3
3
3
3
3
11
22
6
11
3
3
6
6
3
3
3
3
3
6
3
3
3
3
18
1
1
1
1
2
1
1
4
10
1
2
1
1
1
1
1
5
10
2
5
1
1
2
2
1
1
1
1
1
2
1
1
1
1
8
1
14
3
105
388
268
7,177
493,167
28,847
408
190
69,375
47,392
1,177
4,491
2,001
69,227
66,409
26,956
141,640
242
1,459
60
2,897
242
4,493
651
20
9
79
788
5,041
3,877
99
34,596
0
0
0
0
0
0
1
48
3
0
0
7
• 5
0
0
0
7
6
3
14
0
0
0
0
0
0
0
0
0
0
0
0
0
0
3
•» EPA developed this estimate based on the Mail
Survey d«l« for the subset of facilities analyzed. '
Becaust) capacity conditions have changed
dramatically since 1881, the waste figures were
scaled up to I960 (the baseline for this analysis)
uf tag different factors for commercial (13.7) and
noncommercial (1.13) incinerators. The commercial
scaling factor was based on an annual survey of
commercial capacity conducted by EPA (USEPA,
Office of Policy Analysis, "Survey of Selected Firms
in the Commercial Hazardous Waste Management
Industry"). Because a similar type of annual survey
could not be located for noncommercial facilities,
the ratio of industrial production in 1988 versus 1981
was used as a scaling factor. (Source: Board of
Governors of the Federal Reserve System, total
industrial index).
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Federal Register /. Vol. 55, No, 82 /;
27, l,9pO /
TABLE 4.—DISTRIBUTION OF HAZARDOUS WASTE INCINERATORS AND HAZARDOUS WASTE COMBUSTED BY SIC—Continued
SIC
7391
8062... ...
8221
9661 .. . ...
9999.. . ...
, Total :
. - . Description
Research/develop, labs ....;
Gen. med./surg. hospitals ............ . .
Colleges, universities........:.
Space research-& technology ......;.. .
Nonciassifiable establish. -. .'. .'. . - • ~
. • Facilities [' ' . - V „
No.
. 17
, 3
, 6
3
8
227
Percentage
-• ' -7
• • • •!•••- 1
,'•.- 2
:. , 1
- ' .-•!' 4
, " V 100
Quantity of hazardous waste
combusted
(KK<3/Year)
1,333
42
120
364
19,716
1,035,362
• Percentage
0
0
0
.0
1 -. 2
100
1 Numbers may not total because of rounding,
1. Costing Methodology and Unit Costs
bf Control
Toxic Metals Limits. As discussed,
EPA is proposing a site-specific risk
analysis to ensure that emissions of
metals do not pose unacceptable
increased risks to human health. EPA is
also proposing to allow permit Writers
and applicants to demonstrate
compliance with the proposed risk-
based standards using a conservative
screening analysis for feed rates and
emissions, In conducting this costing
analysis, EPA assumed that each facility
would attempt to show compliance in a
sequential, fashion, as shown hi Figure 1.
EPA assumed that all hazardous
waste incinerator operators would first
attempt to demonstrate compliance with
the proposed standards using the Feed
Rate Screening Limits. Prior to the Feed
Rate Screening analysis, EPA assumed
that all incinerator operators would
incur costs to analyze the toxic metal
constituents as part of the Waste
Analysis Plan for the permit. In addition,
the Feed Rate Screen would require
incremental analysis of metals in the
waste feed as part of a trial burn. For
both the waste characterization and the
feed analysis, the facilities will not incur
additional costs for sampling, which is
already conducted under existing
regulations.
.EPA assumed thatall facilities
passing the Feed Rate Screen would be
awarded a permit and would not incur
additional permitting expenditures. The
failing facilities would then attempt to
demonstrate compliance using the
Emissions Screening test. The Emissions
Screen would-require sampling and
analysis of metals in the stack exhaust
gas. -.. •'
In the event that a facility would fail
to satisfy the requirements of the
Emissions Screen, the facility would
conduct a Site-Specific Risk
Assessment. If the risk assessment. .
predicted that the facility would pose an
aggregate lifetime cancer risk to the
maximum.exposed individual (MEI) in : :
excess of 1X10~5 S1 (summed across all
carcinogens emitted by the facility) or
an increased likelihood of adverse
(noncancer) health effects, the costing
analysis assumed that the incremental
emission reductions would be achieved
, using APCDs.9 2 This latter assumption
may result in an overestimate of
compliance costs because incinerator
operators in some situations may be
able to modify their combustion
practices (e.g., blending) at little or no
incremental cost to meet the standards.
BILLING CODE 6560-50-M
' 91 In selecting 8 risk threshold of 10~5 for these
rules, EPA considered risk thresholds in the range of,
W~* to 10~|>. As discussed in Section I.D. of Part
Three of the text, the Agency requests comment on
alternative risk thresholds. ,
92 In this analysis, EPA assumed that a
cumulative lifetime cancer risk of 9.5X10-» or
greater was equivalent to 1X10"5 through rounding
and other imcertainties'. Similarly, a ratio of 0.95 or •
greater calculated as part of screening analyses or
the analysis of honcahcer risks (i.e.; the ratio of the
predicted ambient concentration divided by the
EAC) was assumed equivalent to 1.0.
-------
17896
Federal Register / Vol. 55, No. 82 / Friday, April 27, 1990 -
Rdes
24
Figure J
Overview of Costing Approach: Proposed Metals Limits
Compliance Demonstration Strategy
Incremental Unit Costs
Preliminary
Waste
Characterization
mmtmmmammm
All facilities conduct the preliminary wasie
characterization and the feed rate screen.
Per—* Awarded
Pursue
Emissions Screen
• Waste Stream Analysis (permit application): $3,81 Q
(one composite sample of six waste streams) [a]
• Waste Feed Analysis (trial burn): $6,008 per
HW incinerator unit [a]
Emission
Screen
Pass
-Q
Fail
Permit Awarded
Pursue
Site-Specific
Risk Assessment
> Emissions sampling and analysis: $25,200 per
HW incinerat««*jnit
S'te-Soec.fc
Rsk
Assossre-t
Pass
Permit Awarded
Install
APCDs
• Risk Assessment: $7,500 per incinerator tacility
(non-complex terrain); and S12.500 per incinerator facility
(complex terrain). •
PLUS
• Collection of Site-Specific Meteorological Data:
550,000 .for 30% of facilities in non-complex
terrain, and 70% of facilities in complex terrain
APCDs
• Capital Costs: S30.000 to S660.000 per HW incinerator
unit
• Annual Operating Costs: S5.000 to $180.000 per
HW incinerator unit
{a] Samp-es a'e .'ready collected under ex.st.ng regulations: therefore, there is no incremental cost associated with sampar.g
BtlUNQ COOE GKO-50-C
-------
Fedteral'Register .'/-/yQl;;.'55,' Nov-82;,/ .Friday,- ApriL,27,.19gp / foogpsed .
5^gSg7aEai3£ia^^23gEaa~*^-.J4*ii^J^35r£^E^S^ggE^^
- Figure 1 has also summarized the unit
costs associated with the metals costing
analysis._As shown, the estimated.
incremental unit cost of completing the ,
preliminary waste characterization
analysis as part of the permit for six
blended waste streams is $3,810.93 94
The additional analysis costs for the
Feed Rate Screen are approximately"
$6,000 per hazardous waste incinerator
unit; the incremental sampling and
analysis costs for the Emissions Screen
are $25,200 per hazardous waste
incinerator unit.95 The risk assessment
costs range from $7,500 for a facility in
noncomplex terrain to $12,500 for a
facility in complex terrain.96 In addition,
EPA assumed that 30 percent of the
hazardous waste incinerators in
noncomplex terrain and 70 percent of
the hazardous waste incinerators hi
complex terrain would need to gather
site-specific meteorological data at a
cost of $50,000.97 EPA requests comment
on the reasonableness of the risk
assessment cost estimates.
Because the collection of site-specific
data could take as long as one year, EPA
recommends that the nearest STAR data
be used until the site-specific data can
be gathered. At that time, the permit
could be reported, and the site-specific
data used.
For each hazardous waste incinerator
that was esimated to pose an aggregate
lifetime cancer risk to the MEI in excess
of 1 x 10"5 and/or an increased
likelihood of noncancer effects, a best
engineering estimate was developed for
a treatment train and the associated
costs needed to meet the estimated risk
reduction level. The APCD capital costs
ranged from $30,000 to $660,000 per
incinerator 'unit ($40,000 to $680,000 per
incinerator facility), depending on the
facility type, size, existing equipment,
'B3 In assigning the costs for the waste. •
characterization, it was assumed that ten waste
streams are blended to one. This decision rule is
limited because the 10-to-l blending assumption will
not necessarily be representative for all
incinerators. After blending has been assumed, the
waste characterization unit costs were then
allocated as follows: 0 to 6 blended streams (unit
costs remain the same); 7 to 12 blended streams
(unit costs are multiplied by two); 13 to 18 blended
streams (unit costs are multiplied by three).
Information on the number of waste streams ,
combusted at each HW incinerator was found in the :
Mail Survey. ....... . ...... :
9t Memorandum to Frank Smith, USEPA, from.
Bruce Boomer, MRI, "Sampling and Analysis Cost
Impact of Draft Proposed Incineration Regulations
for Metals; MRI Project No. 9029-L-12," July 31, '
1987. •
95Ibid.
06 Verssr Inc., "Air Dispersion Modeling-as
Applied to Hazardous Waste Incinerator
Evaluations: Draft Report," May 13,1987.
and the amount of risk reduction-
required; annual operating costs ranged
from $5,000 to $180,000 per incinerator
unit ($10,000 to $180,000 per incinerator
facility).98
EPA assigned the costs for the
preliminary waste, characterization and
completion of the Feed Rate Screen to
all hazardous waste incinerators
combusting wastes containing metals.
The allocation of subsequent costs '
depended on the success with which
each incinerator passed or failed each of
the screens and the risk assessment. The
costs of gathering additional
meteorological data were randomly
assigned among those facilities
, performing a risk assessment.
The decision rules discussed in part
Three of today's proposed rule were
used to predict which facilities would
fail the Feed Rate, Emissions, Site-
Specific'Risk Assessment tests for.
carcinogenic and noncarcinogenic
metals. The allowable screening limits
were selected for each facility as a .
function of terrain (complex and
noncomplex), terrain adjusted effective .
stack height, and landUisage (rural
versus urban). EPA identified the terrain
for each incinerator analyzed. Effective
stack height was calculated using
information from the Mail Survey/
Information on land usage was not
readily available; therefore, the more "
conservative screening limits were used,
as directed by today's proposed rule.
.To complete the. screening analyses
and the risk assessment for the selected
toxic metals, facility-specific
information in the following parameters
was needed:.metal constituent
concentrations,in the waste; quantity of
each metal emitted; a point estimate of
the maximum ambient air concentration
outside of the fenceline of the
incinerator, and health risk factors
(either unit cancerjrisk numbers :or
acceptable Reference Air Concentration
levels (RACs) for noncancer effects). .
The analytical approaches used to - -
gather these data are discussed later in
the Risk Assessment section.
HCI Limits. Identical to the proposed -
-approach for regulating metals, EPA is
proposing a site-specific risk analysis to
ensure that HCI emissions do not pose
unacceptable risks. Again, EPA is
proposing conservative Feed Rate and
" Ibid. Estimates of the percentage of facilities
requiring additional meteorological data estimated
byVersarlnc.
""Memorandum to Temple, Barker, & Sloane, Inc. -'
from Doucet & Mainka, P.C., "Hazardous Waste
Incenerator Mini-RIA: APCD Cost Increments for
One Percent Chrome VI Scenario," September 28,.
1987. _'--:•- ..•.'•.'.• ;
Emissions Screening Limits for HCI to
simplify the permitting process. These
HCI limit!! differ from those established
for metals only in that they provide
standards; relating to both short-term
and longT!term human health effects.
The costing analysis assumed, as it '
did for metals, that all hazardous
incineratcir facilities would first attempt
to demonstrate compliance with the
' proposed HCI standard by performing
the Feed Rate Screen; all facilities
failing the' first screen would then opt for
the Emissions Screen and any facilities
failing the1 second screen would
undertake! the Site-Specific Risk ,
Assessment (see Figure 2). If the risk
assessment predicted risks to human' -\ ,
health above the acceptable levels, the
costirig analysis assumed that APCDs
would be installed to reduce HCI
• emissions; For spme facilities this may
be a conservative (high cost) option
because there may exist lower cost
options (e.g., pretreatment and waste . •'
blending) that the Agency was not able
to consider within the scope of this
analysis.'! . , -.'"''..- -"-'
: JEPA believes that there would be no
incremental costs attributable to the
preliminai-y waste characterization, the
Feed Rate Screen or the Emissions
Screen for HCI; because the sampling .
and analysis of chlorine required for
each of these tests is already performed
under the permitting conditions of "
existing subpart O of the Subtitle C
regulations for .hazardous waste .'
incinerators. The incremental costs for
performing a Site-Specific Risk
Assessment for HCI are equivalent in
magnitude to costs for a metals risk
assessment; however, facilities -'
conducting a metals risk assessment .--
were not expected to incur additional
cost. i . /•-;. - '•
For each incinerator"that failed to *
meet the baseline HCI emission
standards, considering both short-term
and long-term effects, the cost analysis
"developed a best engineering estimate'of
the treatment train and the associated
costs needed to meet the estimated risk
reduction.1?9 A detailed facility-specific
analysis was not performed. The APCD
capital costs for HCL ranged from
$17,000 to $430,000 per incinerator unit;
. depending on the type of combustor,
size, existing control equipment, and the
amount of risk reduction required;
annual operating costs ranged from .:•"•'
$1,000 to $154,000 per incinerator unit
(seeFiguM 2). " ' .
BILLING CODE
90 Ibid.
6SSO-5D-M
-------
17898
Federal Register / Vol. 55, No. 82 / Friday, April 27,1990 / Proposed Rules
25
Figure 2.
Overview of Costing Approach: Proposed HCI Limits
Compliance Demonstration Strategy
Incremental Unit Costs
Prolimma'y
Wasto-Charactertzatson
• Waste Stream Analysis (permit application):
no incremental costs [a]
All facilities conduct the preliminary waste
characterization and the feed rate screen.
A?**** Permit Awarded
Feed
Rato Screen
rass
-Q
Fail
"^^^^ Pursue
Emissions
Qr-roan
Emission
Screen
^P**1* Permit Awarded
Pass
-Q
Fail
• Waste Feed Analysis (trial burn) :
no incremental costs [a]
• Emissions sampling and analysis:
no incremental costs [aj
Pursue
Site-Specific
Risk Assessment
Permit Awarded
APCDs
• Risk Assessment :$7,500 per incinerator facility
(non-complex terrain); and $12,500 per incinerator
SiJe-Soaciftc
R>sk
Assessment
JV
Pass
-Q
Fail
Install
*" APCDs
PLUS. ,
• Collection of Site-Specific Meteorological Data :
$50.000 for 30% of facilities in non-complex
terrain, and 70% of facilities in complex terrain, [c
• Capital Costs: $17,000 to $430,000 per HW incinerator
unit
• Annual Operating Costs: $1,000 to $154,000
per HW incinerator unit
[a) Sampling and analysis ol chlorine is already conducted under the permitting conditions of existing Subpart O
of the Subtitle C regulations for HW incinerators.
(b) No additional risk assessment costs were assigned to a faclility in the costing analysis K it was already conducting a
risk assessment for metals. • ,
ic] No additional data gathering costs were assigned to a facility if it was already performing this work for the metals
nsk assessment.
•ttUHQ CODE tSVhSO-C
-------
The decision rules discussed in part
Three of today's rule were used to
predict which facilities would fail the
Feed Rate, Emission, and Site-Specific
Risk Assessment tests. The Risk
Assessment section below provides
more detail on the information needed
to complete these tests, specifically: the
quantity of chlorine emitted; a point
estimate of the maximum short- and
long-term ambient concentration outside
the fenceline of the incinerator, and
health risk factors (short-term and long-
term RAGs).
CO Limits. EPA believes that
hazardous waste incinerators should
operate at a high combustion'efficiency
to ensure that HCs do not pose an-
unacceptable risk to human health.
Because CO is one of the best available
indicators of combustion efficiency, EPA
is proposing limits on CO emissions. In
particular, EPA is proposing a CO limit
of 100 ppmv. If a facility cannot meet the
proposed CO limit, higher limits will be
acceptable provided that HC emissions
are not associated with unacceptable
human health risks or do not exceed a
good operating practice-based limit.
EPA is proposing a tiered approach for
determining how HC are regulated. This
approach is similar to that being
proposed for metals and HC1.
Accordingly, the costing methodology
for PICS also resembles the analysis
completed for metals and HC1 (see
_ Figure 3J.
Tier lis a 100 ppmv CO limit. If a
facility can demonstrate compliance
with this standard, this will be the
. permit limit. There is no incremental
cost associated with this demonstration.
because emissions information is
already generated as part of the trial
burn.
If a higher CO limit is sought as a
permitting condition, the facility must
demonstrate that HC levels are
acceptable under Tier II. Although the
Agency is proposing a health-based
approach to limit HC, it is requesting
comment on limiting HC to a
technology-based level of 20 ppmv. As
discussed previously in today's notice,
the Agency now prefers the technology-
based approach. Nonetheless, we have .
projected implementation costs for the
health-based alternative because the
costs would be higher. Under the health-
;based approach, the facility would be
required to demonstrate that HC
emissions do not pose a cancer risk
greater than 1X10 ~5 10°. The facility
can compare HC emissions with
Screening Limits that the Agency has
established or it can conduct site
specific dispersion modeling. The
incremental cost of performing the Tier
II analysis is the sampling and analysis
required to determine emissions of
THCs. The Agency has estimated a
typical incremental cost for this test at
$6,500 per incinerator unit.101
If, under the risk-based alternative to
assessing HC. emissions, a facility fails
Tier II using the decision rules discussed
in part three of today's proposed rule, a
Site-Specific Risk Assessment would be
performed. The cost of the risk
assessment is the same as that for
metals! and HC1. However, no
- incremental cost was assigned to a
facility in this analysis if it was already
incurring risk assessment costs for
either chlorine or metals.
BILLING CODE 6560-50-M
100 In selecting a risk threshold of 10"5 for these
rales, EPA considered risk thresholds in the range of
10-«.tp 110-". As discussed in Section J.D. of part
three of the text, the Agency requests comment on •
alternative risk thresholds. '
101U8EPA, Office of Solid Waste, internal •
analysis'. ; . ;'
-------
17900
Federal Register / Vol. 55, No. 82 / Friday, April 27,1990 / Proposed Rules
Figure 3
Overview of Costing Approach: Proposed CO Limits
Compliance- Demonstration Strategy
Incremental Unit Costs
CO Monitoring
• Capital Costs: $40,000 per HW incinerator unit
• Annual Operating Costs: $1.200 per HW incinerator unit
• Combusting of Auxiliary Fuel during Upsets: $100 par
million BTU of incinerator capacity
AH facilities conduct
CO momtofipg ana Tier I
Permit Awarded
Tiarl
Pass . Emissions Testing: No incremental costs [a]
-Q
Fail
^•"•w Pursue Tier II . . •
Tier I!
M«mam. p8rmit Awarded
*r • Sampling and Analysis of THC Emissions: $6,500 per
x*fass • • HW incinerator unit. ,
*%,<. Pursue
pal Site-Specific
^ Risk Assessment -
Site-Specific
Risk
Assessment
JT ' 8 mlt Mwamea terrain); and $12.500 per incinerator facility
Pass . (complex terrain), [b]
"V»4 , .. ... PLUS
Fail Modify
4^ Combustion • Collection of Site-Specific Mateorological Data
^"«""« practices $50,000 for 30% of facilities in non-complex
terrain, and 70% of facilities in complex terrain.
*~
Mod.fy
Combustion . incremental costs were not estimated, [d]
System/Practcas
(noncomptex
[c]
[a] Emissions testing for CO is already performed under the permitting conditions of existing Subpart O of
tho Subw'.e C regulations for HW incinerators.
[b] No addstwna! risk assessment costs were assigned to a'fadilrty in the costing analysis if it was already conducting a
risk assessment for metals and/or chlorine.
(c} No additional data gathering costs were assigned to a facility if it was already performing this work for the metals
and/or chlorine risk assessment. • '
fd] Incremental costs were not estimated because (1) there was insufficient information on tha technical response, ana
{2) a small number of facilities (approximately five) wero expected to incur costs.
BfUIWJ COM CSO-50-C '
-------
Ruiesr
17901
For those facilities with HC
concentrations higher than allowed,
EPA assumed that the incinerator
operator would modify the combustion
system and/or practices to reduce CO
(and HC) levels. EPA did not develop
estimates of the costs associated with
combustion modification because (1)
there was insufficient available
information to estimate the appropriate '
technical response, (2) very few
facilities were expected to incur costs
(approximately five facilities], and thus,
(3) the incremental compliance costs
were not anticipated to be significant at
either the national or individual industry
sector level.
To demonstrate compliance with the
final permitted CO levels, this analysis
assigned additional monitoring costs to
each incinerator. The CO monitoring
program included a continuous oxygen
monitor and a data-logger for
continuous oxygen correction. The
capital costs were estimated at
approximately $40,000 per incinerator
unit; annual operating costs were
es timated at roughly $1,200 per
incinerator unit.102 Because of time and
resource constraints, this analysis did
not include the proposed alternative CO
format described in today's proposed
rule, although it is expected to provide a
lower-cost alternative.
The costing analysis also included the
incremental expenses associated with
combustion of auxiliary fuel during
periods of upset, as required in today's
proposed rule. The annual incremental
cost of the auxiliary fuel was estimated
• at roughly $100 per 106 Btu of incinerator
capacity based on 50 upsets of one-hour
duration per year.103 This cost was
assigned to all incinerator units.
Because of data limitations, this
analysis was unable to estimate
emissions of CO and THCs for the
. loz Douoet & Mainka analysis of "Guideline for
Continuing Monitoring of Carbon Monoxide at
Hazardous Waste Incinerators," January 13,1987
prepared by Pacific Environmental Services for
USEPA.
103 Memorandum to Temple, Barker a Sloane,
Inc. from Douoet & Mainka, P.C., "Hazardous Waste
Incinerator Mini-RIA Supplemental Information to
Unit Costing Methodology (draft)," August 18,1987.
facilities, analyzed in the Mail Survey.
As a result, it was not possible to
quantify: the number of facilities that
would pass Tier I, Tier II, and the Site-
Specific Risk Assessment using the
methods employed in the metals and
HC1 analiysis. Alternatively, a decision
tree analysis was used to obtain
approximate estimates regarding tLe
numbers of facilities that might be
subject to incremental impacts and costs
associated with the proposed CO
standards.
Figure 4 illustrates the decision tree.
Based on available engineering opinion,
the Agency believes that the only
facilities that would be unable to meet
the proposed CO limits would be fluid
bed incinerators and incinerators
feeding 10 percent or more of their
waste hi large containers. The Agency
estimates; that a subset of 19 facilities (6
fluid bed and 13 burning containerized
wastes) would be in this category and
assumed to pursue Tier II.
BILLING CODE 6560-50-M
-------
Figure 4
Decision Tree for Detormlnlng"Comp!ianca witn the CO Standards
Permit Awarded.
No Additional Reductions
In CO Required
All Incinerators
Perform Tier I
(227facilities)
Pass Tier I
(208 facilities)
Fail Tier I
(19 facilities)
Decision Node
Chance Node
[a] Accept Tier I Failure;
Reduce CO Levels
Permit Awarded; No Additional
Reductions In CO Levels Required
Pursue Tier II
(19 facilities)
Pass Tier II
(9 facilities) .
P=.50
P-.50
Fail Tier II
(10 facilities)
Accept Tier II Failure;
Reduce CO Levels
P=1
Perform Site-Specific
Risk Assessment Pass Rjsk Assessment'
("ib facilities) ,j£r (5 facilities)
=.50
Permit Awarded;
No Additional CO
Reductions Required
[a] Only fluid bed incinerators and incinerators feeding ten percent of their
waste in large containers fail. This decision rule was based on best engineering judgement.
[b] Probability; an assumed probability equal to zero indicates that that no one will decide to modify
their combustion practices/systems after failing Tier I or Tier II.
P=.50
Fail Risk Assessment
(5 facilities)
duce CO I evelg
(5 facilities)
I
%w
1-
en
en
n.
CO
CO
o
I
CO
BILLING CODE 6560-EO-C
-------
Federal Register /T Vol. 55, No. .82
-, April 27, 1990 / Proposed Rules
17903
For purposes of determining order-of-
magnitude costs, EPA subjectively
determined that half of these facilities,
randomly assigned, would pass Tierll
(i.e., would be permitted without further
costs). The remaining half would
perform the Site-Specific Risk
Assessment to determine whether
emission control would be required. The
risk assessment costs were assigned to
these facilities (randomly) only if they
were not already conducting a risk
assessment to demonstrate compliance
with either the metals or HC1 standards.
The decision tree analysis continued
by assuming that half of the facilities
performing the Site-Specific Risk
Assessment would pass; the other half
would be subject to expenditures to
meet the de minimi's risk levels. As
discussed above, this analysis did not
estimate the costs of emissions controls
for THCs, although the Agency believes
the number of facilities that would be
required to do so is small, probably less
than ten.
Sensitivity Analysis
As an alternative to the proposed de
minimi's cancer risk level of, ixlo~5
EPA completed a very preliminary
analysis of the cost impacts of
establishing a de minimi's cancer risk
level of IX1CT6. A change in the
proposed de minimis cancer risk level
would change the compliance costs for
meeting the proposed metals and CO
standards. The methodology used to
estimate the incremental compliance
costs associated with each of these
standards is discussed below.
Metals Standards. The metals
standards in today's proposed rule
would necessitate expenditures in five
areas: preliminary, waste
characterization; the Feed Rate Screen;
the Emissions Screen; the Site-Specific
Risk Assessment; and APCDs. The cost
analysis assumed that all facilities
would perform the preliminary waste
characterization a~nd the Feed Rate
Screen; therefore, the alternative de
minimis standard would not change
these costs. A more stringent risk-based
standard would, however, increase
compliance costs in" the other two areas.
To identify the additional facilities
that would fail the Feed Rate and
/Emission Screens under a more stringent
de minimis risk level, the risk-based
Screening Limits developed by EPA
were used with one adjustment. The
Screening Limits for the carcinogenic
metals were reduced by an order of
magnitude to reflect the 1X1CT6
standard. Additional facilities predicted
to fail the Site-Specific Risk Assessment
were identified by comparing the.
estimated lifetime cancer risk to the MEI
for each incinerator facility against the
alternative risk level of IX 10~6.
The incremental compliance costs
associated with more facilities
conducting the Emission Screen and the
Site-Specific Risk Assessment were
estimated using the unit cost estimates
described above. An engineering
analysis to identify the appropriate
APCD at each hazardous waste
incinerator facility failing the risk
assessment has not been completed at
this time. As a result, EPA approximated
the incremental APCD costs for two
groups of incinerator facilities:
• Facilities already failing the risk
assessment at IX 1O~a The costing analysis
' assumed that to meet the 1X 10~6 standard
these facilities would incur APCD costs at
least twice the estimated costs to meet the
1X10"5. ' .
• Facilities failing only the IX 1O~e
standard. The costing analysis assumed that
these additional facilities would experience
APCD costs similar to those estimated for the
facilities failing the IX10"5 standard. The
average APCD expenditure for the proposed
1X1CT5 standard was calculated and applied
to those facilities failing only the alternative
IX10" "standard.
There are limitations to the APCD cost
calculations. For example, the costing
analysis assumes that the control
requirements for the new facilities in the
analysis are identical to those in the
1X 10~s analysis. In addition, the
facilities already failing the risk
assessment at the proposed standard -
may incur much higher APCD costs to
achieve the IX 10~6 risk standard.
CO Standards. Under the health-
based alternative for assessing THC
emissions, a more stringent de minimis
risk standard would increase
compliance costs for facilities
attempting to demonstrate that CO
emissions in excess of 100 ppm (the
proposed standard) are not associated
with unacceptable human health risks.
In particular, a more stringent risk
standard would increase the number of
facilities needing to complete the Site-
Specific Risk Assessment (i.e., more
facilities failing Tier II) and modify
combusion practices to reduce CO
emissions to an acceptable level (i.e.,
more facilities failing the risk
assessment).
As discussed above, a decision tree
analysis was used to estimate the
number of facilities that would be
subject to incremental costs and impacts
associated with the proposed CO
standards. The decision tree was
modified to reflect the 1X10~6 standard
by increasing the probability of failing
Tier II and the risk assessment from
P=0.50 to P=0.75 (See Figure 3). The
incremental compliance costs
associated with more facilities
conducting the Site-Specific Risk
Assessment, as well as more facilities
needing to modify their combustion
practices, were estimated using the unit
costs described above.
2. Results;
Proposed standards. The Agency
estimates the total annualized
compliance costs associated with
today's proposed Tequirements for
existing hazardous waste incinerators at
approxinmtely $6.2 million. Total
incremental capital costs are
approximately $34 million; the total
incremental annual operating and
maintenance costs are roughly $3
million. These nationwide costs were
extrapolated from the subset of 82
facilities analyzed to the current
population of 227 hazardous waste
incinerators. Capital costs were
annualized at a (historical) real discount
rate of 3.7 percent over a period of 15
years; one-tune costs (e.g., preliminary
waste characterization costs) were
annualized over the assumed life of the
permit (teii years).
The total estimated compliance costs
for today's: proposed rule are
summarized in Table 5. As shown, the
potential need for APCDs to reduce
chlorine aiid metal emissions accounts
for half of the estimated costs. An
additionally percent is explained by the
proposed requirements for CO
monitoring; and combustion of auxiliary
fuel during periods of combustion upset..
The Feed Rate and Emissions Screens
account for 17 percent of the total costs.
The remirung cost components
contribute 3 percent or less to the
estimated iincremental compliance.
Because of substantial uncertainties
inherent in the accuracy of available
data and the general nature of the
engineering costing and risk assessment
approaches utilized, the Agency urges
caution in the interpretation and
application of these results.
Sensitivity analysis. Table 6
summarizes the estimated total and
iricrementeiLarinual compliance costs
associated with the alternative de
minimis cancer risk of 1X 10~6. The
incremental costs are presented against
the baseline (i.e., before regulation) and
the proposed de minimis risk level of
IXIO'6.104
104 In selecting a risk threshold of 10~5for these
rules, EPA considered .risk thresholds in the range of
1(T4 to 10"6. As discussed in section I.D. of Part
Three of the t«xt, the Agency requests comment on
alternative risk thresholds.
-------
1790-1
Federal Register / Vbl. 5S, No. 82 f Friday? April 27, 1990 / Proposed Rules
As indicated in Table 6, the more
stringent risk-based standards for
carcinogens results in a higher total
annual compliance cost of
approximately $9.7 million. This is an
increase of roughly $3.4 million over the
proposed lX10~*risk standard. Almost
all of the increase in cost
(approximately 97 percent) can be
attributed to more facilities needing to
control further emissions of carcinogenic
metals. In the sensitivity analysis, an
estimated total of 53 existing hazardous
waste incinerator facilities (or an
increase of 22 facilities over the
estimated 31 facilities requiring APCDs
to meet the 1X10"8 standard) would
need to reduce metal emissions below
current conditions.
OiltlNCi CODE 85C»-KJ-M
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VolvSg,' No. 82 /Friday, -April 27,1990 / Prbp&sffd Rules
17905
Table *«*• S*" .-• •
SUMMARY PF INCREMENTAL COMPLIANCE COSTS: ' PROPOSED -STANDARDS,' -
(thousands of 1986 dollars) : ,
• " - "' ' Number of
Percentage • Facilities
Compliance Cost Capital and Operating and Annualized of Total j Performing
Component One-Time Costs Maintenance Costs Costs1 Annunli^ri rn«i-« Annlvoin2
Metal Standards -
Preliminary Waste
Characterization , $ 717 N/A $ 87 ' is
reed Rate Screen 1,440 N/A 175 3 '
Emission Screen 4,913 N/A 596 10
ApCDs 5.?80 $1,401 1,928, 31
Subtotal $13,050 $1,401 $2,786 45s
HCL Standards '
Preliminary Waste
Characterization^5 - $ Q nj/A $ 0 b*
Feed Rate Screen-' 0 N/A 0 0*
Emission Screen-' 0 N/A 0 0
APCDs 4,378 ' $ 811 • 1,197 19 :
Subtotal $4,378 $ 811 $1,197 19S
CO Standards •. . . •
rier I4 $ 0 N/A $ 0 OS
Tier 11 . • 198 N/A . 24 <1
Modify Combustion' N.A. N.A. N A N A
CO Monitoring 'including • . .. ,..•'..••
auxiliary fuel costs) 12,000 '.. $ 620 1,657 27
Subtotal ' $12,198 $ 620 . $1,699 . 27S
Site-Specific
Risk Assessment6 $ 3,958 ' N/A " $ 4fU w>
•
Iotal " $33,584 $2,832 $6,163. 100S
N/A = Not applicable.
N.A. = Not available.
Capital costs were annualized at a (historical) real discount rate of 3.7 percent over
equipment (15 years). One-time costs (e.g., preliminary waste characterization) were a
life of the permit {10 years).
^Baaed on recent information provided by HWDMS, there are currently 227 HW incinerators
There are no incremental costs because these tasks are already performed as part of the
There are.no incremental cots for Tier I, which is already performed as part of the tri
A costing analysis was not completed for this category at the present time because (1)
information on the technical response, (2) few facilities (five) were expected to incur
proposed requirement was not expected to result in significant national expenditures.
These costs may apply to one or all three of the proposed standards.
. •
1A7
- . 131
31.
log
166
45
- 10
' , 5
227 ,
QQ
the estimated life of the
nnualized over the assumed
nationwide.
trial burn.
al burn.
there was no available
costs, and, (3) this
- •
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17906
Federal Register / Vol. 55, No. 82-/ Friday, April 27,1990 / Proposed Rules
V-17
lab la
SENSITIVITY ANALYSIS: SUMMARY OF IOIAL AND INCREMCNIAL COMPLIANCE COSTS
FOR 1 x ItT6 DC HINIMIS RISK
Compliance Cost
Component
(thousands of 1986 dollars)
Annual!zed Cost*
Increment Over
1 x ICT5
^ Proposed Standard
Number of Facilities
Performing Analysis^
Hetal Standards
Preliminary Waste
Characterization
feed Rite Screen
Cniaaion Screen
APCOa
Subtotal
HC1 Standards
Preliminary waate
Characterization4
Teed Rale Screen4
Cniaaion Screen3
APC09
Subtotal
CO Standards
Her I*
tier (I
Modify Coaoustion4
CO Monitoring including
auxiliary fuel costs)
Subtotal
Site-Saneifie
Hiah Assessment*
$6,178
$ 3
0
0
1,197
$1,197
$ a
24
N.A.
1,676
$1,702
$ 0
0
61
J.334
$3,395
Total
167
167
153
53
199
199
166
45
227
19
11
227
Increment Over
1 x 1Q-5
Proposed Standard
0
0
22
22
92
$3,487
N.A. r Not available.
'includes! annual Q4M coats, if any, plus annualized caoital or other one-tirae coat(s). Capital,
Celts wera annuitized at a (historical), real discount rate of 3.7 percent over the estimated life
of thB oquipoent '15 years). One-time coats fe.g., preliminary waste characterization} were
annoalizedi over the assumed life of the oermit '10 years).
Z3«sed on recent information provided by HNDMS,. there are currently 227 facilities with one or more
MW incinerators nationwide including- Puerto Rico-.
'fotal capital costs for all requirements in the sensitivity analysis were approximately
$45 tullion (roughly $11 million more than the total-capital costs estimated for compliance- with a
1 x 10~5 de minimis risk standard). Total OSM costs were approximately $5.3 million (roughly
$1.5 Bullion more than the total 04H costs estimated for compliance with a 1 x 10"* cte mtnimia
rifk standard).
4lhere are no incremental costs because- these tests are already performed as part of .the- trial
burn*
5thero are no increnwntal costs for lier I, which is already performed as part of the trial burn.
*A coating analysis was not completed for this category at the present time because (1) there was
no available information on the technical response, (2) few facilities (five) were expected to
incur coats, and (3) this proposed requirement was not expected'to result in significant national
expenditures.
7these eoeta may apply to one or all three of the proposed standards. '
BILUHO CODE 6SJO-50-C
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Federal Register / Vol. 55,
.f, ,.-? *••- s;*'si ..,, i-^^q1 }.-..---,t-,,s«T
April 27, 1990 / Proposed Rules
17907
D. Economic Impact Analysis
A preliminary economic impact
analysis was conducted for the subset of
facilities evaluated from the Mail Survey
based on the compliance costs for the
proposed and alternative (sensitivity
analysis) standards described above.
Results were also extrapolated to the
population of existing hazardous waste
incinerators. The methodology and
results of this analysis are detailed
below.
1. Methodology
Based on a review of alternative
analytical approaches and available
financial data, first order economic
impacts were approximated by
calculating (1) the ratio of annual
incremental compliance costs to average
gross profit before tax and (2) the ratio ,
of annual incremental compliance costs
to the average cost of production for
affected facilities at the four-digit
industry level of the standard industrial
classification (SIC) system. These ratios
were used to identify the potential ,
increase in production price and the
reduction in gross profitability for
affected industries resulting from
compliance with the proposed
requirements.
Implicit in the ratio calculations is the
assumption that each facility absorbs
the costs of compliance. Although the
decision to pass through costs is a
function of market response (i.e., the
price elasticity of demand for the
facility's product), this effect could not
be quantified because of time and
resource constraints. However, the
assumption that all costs Would be
absorbed will provide, in general, a
conservative .estimate of predicted,
impact. This is particularly conservative
for commercial hazardous waste
incinerators which, given the seemingly
extreme inelastic demand for
incineration capacity in recent years,
will probably be able to pass the
incremental compliance costs through to
the customer.
The average cost of production and
gross profit at the four-digit SIC code
level were calculated.using data from
the 1984 U.S. County Business Patterns
and the 1984 Annual Survey of
Manufacturers. In particular, these
sources were used to derive an estimate
of average net cash flow from
operations (CFO), taken as a crude
measure of gross profit, and average
cost of production (COP) at the four-
digit SIC level.
The financial ratio analysis was
performed on a facility basis using only
average industry financial data. It was
impossible to consider variability in
financial impact by plant size,
productivity or other measure of impact
because the necessary data were not
available within the scope of this effort.
The use of average industry data could
substantially understate adverse impact
for some individual facilities.
Using the annualized compliance
costs estimated for each facility and the
average industry financial data, the two
financial ratios described above were
calculated to assess impact. Adverse
economic impact was indicated if either
(1) the compliance costs increased
production costs by more than 1 percent
or (2) compliance costs accounted for
more than 1 percent of net cash flow
from operations. These thresholds are
.more conservative than those used in
many recent EPA analyses. Generally,
EPA has identified significant impact
when either the ratio of compliance
costs to COP or the ratio of compliance
costs to CFO is greater than 5 percent.
2. Results i
Proposed standards. Table 7
summarizes the distribution of economic
impact for each of the financial ratios
calculated. As shown, the proposed
regulations will not impose an undue
economic burden on the majority of all
hazardous waste incinerator facilities.
Based on the COP ratio, 6 percent of all
hazardous waste incinerator may
experience adverse economic impacts
because of predicted average increases
in production costs between 1 percent
and 2 percent. The CFO ratio indicates
that appro:icimately 12 percent of
hazardous waste incinerators may
witness decreases in their gross
profitability ranging between 1 percent
and 4 percent. None of the calculated
financial ratios exceeds 4 percent or the/
5 percent hurdle rate generally used by
EPA to determine significant impact.
TABLE 7.—DISTRIBUTION OF ECONOMIC IMPACT: PROPOSED STANDARDS;
Number of Affected Entities with Hazardous Waste Incinerators i.
Impact ratio
Cost of compliance/cash flow from operations
Cost of compliance/cost of production
• Numbers may not sum because of rounding.
0-0.99
percent
199 (88%)
213 (94%)
1-1.99
percent
11 (5%)
2-2.99
percent
0
3-3.99
percenl:
3(1%).
; o
I
4-4.99,
percent
0
0
total (/*/)
227 (100%)
227(100%)
Table 8 presents the distribution of
economic impact by SIC for those
facilities exceeding the 1 percent
threshold. The COP ratio shows
potential significant impact for 14
facilities in four SIC categories. The
.CFO ratio indicates impact for almost
twice as many facilities distributed
among nine different SIC codes. No one
SIC category appears to dominate,
i • ' * "" -
although there are higher predicted
impacts for SIC 2873 (Fertilizers,
Nitrogenous).
TABLE 8.—Distribution of Economic Impact by SIC: Proposed Standards *
Number of Affected Facilities . [
'- - SIC
2421 (Saw mills and planing mills)...... ,
Cost of compliance/cash flow from operations
1-1.99
percent
-3
. '. J
2-2.99 .
percent -
••
3-3.99
percent
.3
Cost of
compliance/
cost of
production
1-1.99
percent
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I79G8
Federal Register / Vol. 55, No. 82 / Friday. April 27, 1990 /
^^BfB^M||BM,.|MMM.|^Biai|i^^i)BBaija^iMBi^aaMaMMBBM^^
TABLE 8.—Distribution of Economic Impact by SIC: Proposed Standards l—Continued
Number of Affected Facilities
SfC
2913 On*"*Wgffi»9)— -——••- — ~~-~..—~— - •
2&2t (Pf»*iJc» rotlorfal) -.I,-, — —~...- __...._....™...~ — .-.« — ...........
285t (Paints and atfed products) •
3223(Gasc») ~ • —
3672 (CaJhoda ray picture tuboa TV) < — —
9909 (Nonctestfiable establishments)
Cost of comp!ianee/cash flow fronr, ofierations
1-1.99
percent
3
3
11
2-2.9ft
percent .
3
3
6
3
. . t4
S-3;89
- percent !
•
-.- ••••••
3
Cast of
compliance/
cost of
production.
1-1.99
percent
3'
3
6
3
f4
«Re^, are sommartrod only forthosefadlfflesexc
* Numbw» nw nol sum because of roumEng^
Sensitivity analysis. The results of tie
financial ratio tests for the sensitivity
analysis are summarized in table 9.
Similar to the results for the proposed
slondardif, the majority of facilities are^
not predicted to incur adverse economic
impact. Based on the COP ratio results,
an estimated a) facilities (approximately
9 percent of the total population} would
face incremental compliance costs
representing between. 1 percent and 4
percent of production costs. The CFO
ratio calculations indicate a larger
fraction of facilities (39 facilities or
roughly 17 percent of the total
population! that could be subject to
adverse financial conditions if the
proposed requirements are enacted.
Although most of these 39 facilities are
not predicted to incur compliance costs
representing1 more than 4 percent of
either net cash flow or production costs,
an estimated 6 facilities could face
compliance costs that are greater than 6
percent of net cash flow. Table la
presents the distribution, of economic
impact by SIC for those facilities
exceeding the 1 percent threshold.
TABLE 9.—Distribution of Economic Impact: Sensitivity Analysis
Number of Affected Entities with Hazardous Waste Incinerators (percent of total):
Impact ratio
Co*t ot comptaca/cash flow from operations
Coat of compliance/cost of production
0-0.99
percent
185
207
1-1.99
percent
22
1T
2-2.99
percent
0
6
3-3.99
percent
11
3
4-4.99
percent
0
0
5-5.99-
percent
a
0>
6-6.99
percent
6
i a
Totaf"
227
227
• Nurobo™ may not sum because ot roundinfl-
TABLE 10.—Distribution of Economic Impact by SIC: Sensitivity Analysis l
Number of Affected Facilities
SfC
2421 (Saw mKs and planing mills) ^r.
2511 (Wood household furniture)
2813 (InduoJrW gasas) .
2819 (Inorganic choroicate}
2621 (PtasUcs material)
2851 (PaJcte and allied products)
2873 (FortffizafS nltrogeneous)
2879 (PMtWdos) — — .
3229 (Gasos) •
3872 (Cathode Ray picture tubes TV)
9899 (Nondassfflabte establishments)
Tote! facilities
Cost of compliance cash flow from operations
t-1.99
percent
6
3
3
3
3
3
3
22
2-2.99
percent
3
3
0
3-3.99
percent
3
-—
3
11
4-4.99-
percent
—
:
o
5-5.99
percent
Of
6-6.99
percent
; —
e
6
Cost ot Compliance Cost of
Production,
f-T.99
percent
: 3"
™.
3
ft
2-2:99
percent
.._.„_............
6
': — ^
3-3.99.
percent
3
:::::::::::
:" : »
"'» RowKi era summarized only for those facilities exceeding tha 1 percent threshold for each calculated financial ratio.
» Numbers may not sum because of rounding.
-------
"17909'
F. Risk Assessment
1. Methodology
A comparative risk assessment was
performed under, existing baseline and
post-compliance conditions for the 82
hazardous waste incinerator facilities
evaluated from the Mail Survey, and
results were assessed considering both
the proposed de minimi's cancer risk
standard of 1 x 10—5 J°5 and the
alternative standard of 1 X 10—6
evaluated in the sensitivity analysis.
The risk assessment was performed for
• both metals and HC1, but there was
insufficient information to quantify
either the baseline or controlled human
. health risks posed by total residual
hydrocarbons at the present time.
For the carcinogenic metals analyzed
(arsenic, cadmium, and hexavalent
chromium), two measures to risk were
estimated: lifetime cancer risk to the -
maximum exposed individual (MEI) and
the annual cancer incidence attributable
to all metals at each facility. For the
noncarcinogens evaluated (HC1, lead,
barium, and mercury), the Agency
identified which facilities may present
an increased likelihood of noncancer
effects by exceedances of health
threshold limits, but the total number of
cases could not be. calculated for these
pollutants. Throughout, EPA's risk
estimates considered exposure through
inhalation only; other exposures (e.g.,
ingestion) were not evaluated.
To estimate the lifetime MEI cancer
risks and any exceedances of
acceptable Reference Air
Concentrations (RACsJ, data were
needed on the following: the quantity of
HC1 and metals emitted by each
hazardous waste incinerator facility; a
point estimate of the maximum ambient
air concentration putside the fenceline
of the incinerator facility; and pollutant-
specific health rish factor (either unit •
cancer risk numbers developed by
EPA's Carcinogen Assessment Group or
the RACs for noncancer effects). These
data were also used in the various
screening analyses described above to
demonstrate compliance with the
proposed HC1 and metals standards. To
predict the incidence of cancer, two .
additional pieces of information were
required; estimates of the ambient air
concentrations over a 50 Ion fallout
radius from the facility, and estimates of
the number of exposed persons at the
various emission concentrations
throughout the fallout area. The steps
taken to gather the necessary data for
the risk assessment are detailed below
Emissions (metals), EPA
approximated metals emissions by
facility utilizing estimates of (1) the
quantity of hazardous waste combusted
Joy RCRA code, (2) the estimated
fraction of metals,in each RCRA code,
(3) the fraction of each metal segregated
as bottom ash and stack emissions, and
(4) metal removal efficiencies for in-
place APCDs.
EPA obtained data on the quantity of
hazardous waste combusted by RCRA
code from the Mail Survey. The toxic
constituent profiles for each RCRA code
were developed by EPA using readily
available information from several
sources, including the W-E-T model and
various sampling efforts conducted by
the Agency to develop the toxic
constituent profiles.106 Waste
characterization data by RCRA code
could not be located for thallium,
antimony, and silver, therefore, these
pollutants could not be addressed in this
analysis. In addition, this analysis could
characterize only the fractions of total
chromium by RCRA code. Based on
available results from recent and
ongoing analyses of combustion sources,
EPA assumed for the present that 1
percent of total clirornium waste feed
and stack emissions would be of the
hexavalent (carcinogenic) species and
that the remaining 99 percent would be
trivalerit.107 It was assumed that all
waste streams are combusted . ;
simultaneously on an annual average
basis because of limited data on this
topic.
To quantify total annual toxic metals
emissions for each facility, EPA
combined the estimated quantities of
each metal combusted annually at each
incinerator analyzed in .the Mail Survey
and engineering estimates on
partitioning and removal efficiencies of
in-place APGDs by metal. The APGD .
removal efficiencies were quantified by
pollutant for each hazardous waste
incinerator using the best engineering
judgement and information on inplace
controls from the Mail Survey.
105 In selecting a risk threshold of 10-6 fof these
rules, EPA considered risk thresholds in the range of
M"4 to W6. As discussed in section 1,0. of Part
Three of the text, the Agency requests comment on
alternative risk thresholds. . -
106 The sampling efforts included: Versar'
"Hazardous Waste and Virgin Oil Assessment of
Baseline Metal Content," April 1986; Mitre,
"Hazardous Waste Stream Trace Metal
Concentrations and Emissions," 1983; and Environ
Characterization of Waste Streams Listed in 40
CER Section 261," 1983. These particular studies
ware selected because they reported pollutant '
concentrations by RCRA code; *
107 Analysis conducted by EPA's Office of Air'
Quality Planning and Standards [coal-fired boilers)
and Office of Water (sludge incineration). However,
mpre recent tests of hazardous waste combustion
indicate that hexavalent chromium may represent
as much as 10% of the total chromium emissions
(see Part Three, H.B. of today's preamble)
Partitioning coefficients Were developed
by pollutant for .solid waste incinerators
to estimate the proportion of metals
segregated as bottom ash and stack
emission!). The analysis assumed that
there is no partitioning in liquid
injectors [i.e., all metals are vaporized)
Emissions (HC1). To estimate HC1
emissions!, EPA collected information on
toe same critical elements used in the
assessment of metals emission rates
(i.e., quantity of hazardous waste • •
combusted by RCRA code, partitioning
and removal efficiencies of inplace
(APCDs). The waste data by RCRA code
. were obtained from the Mail Survey.
To.approximate the quantity of -
chlorine incinerated, EPA first identified
RCRA codes that could potentially
contain chlorine. This list of RCRA
codes was compiled by (l) reviewing
waste sampling data (by RCRA code) in ,
a Supporting document to the existing
RCRA regulations for hazardous waste
incinerators and (2) identifying
additional RCRA codes that could
contain chilorine based on their waste
characteristics,108
To determine the chlorine content,
EPA calculated the average (arithmetic)
chlorine concentration in all waste
combusted in hazardous waste
incinerators using available test burn
data (89 data points) for 23 incinerators
units located throughout the United
States."9The total quantity of chlorine
being combusted was calculated by
multiplying the quantity combusted of
RCRA codes potentially containing
chlorine at each incinerator by the
estimated average chlorine level
(roughly 8 percent). A more detailed
analysis of. chlorine was not performed
in this analysis because of time arid
resource constraints. '
HC1 emissions were calculated
assuming that all chlorine converts to
HCL.In addition, the removal
efficiencies afforded by in-place
controls were considered. The:analysis
assumed thait no partitioning would
occur for HC1 (i.e., all HC1 formed during
the combustion process would be
- emitted as a gas). The analysis
calculated ejnissions by assuming
conservatively that all waste types
reported in lite Mail Survey would be
q "rf wSEF*• ^I8te-Treataent Branch, Office'df
Soad Waste and Emergency Response, "Supportiim
, Documentation ibr the RCRA Incinerator.
Regulations,,40 CIER 284, SubpartO Incinerators," ..
PeerConsuItantsi, Inc. for the Office of Solid Waste
and Emergency Response, October 1984. fNTIS
order No. PB86-a 10293)
»<• USEPA, Office of-Research and Development,
Center for Envircinmental Research Information •
Handbook Permit Writer's Guide to Test Bum
Data, Hazardous-Incineration,"'EPA-625/6-86/012
-------
17910
combusted simultaneously on an annual
average basis. This assumption could
result in an underestimate of the
potential risks from short-term
exposures, as well as compliance costs.
Ambient Concentrations (Metals and
HCI}' EPA predicted maximum and
area-wide ambient concentrations of the
metals and HCI emitted from each
facility using dispersion modeling. It
was outside the scope of this analysis to
estimate maximum ambient
concentration performing site-specific
dispersion modeling. As a result, this
analysts used the predicted ambient
concentrations generated from 10
hypothetical facilities evaluated at each
of 24 sites, which were located in widely
varying terrain (see the discussion in
Part Three of today's proposed rule).110
EPA performed the dispersion modeling
using 18 wind directions and 15 ring
distances, ranging from 0.2 km to 50 km.
Ambient concentrations were estimated
separately for long-term and short-term
exposures.
Health Risk Factors. The unit cancer
risk values were provided by EPA's
Carcinogen Assessment Group and are
listed in Appendix B of today's proposed
rule. The RAC's for the noncarcinogens
were provided by EPA's Office of Solid
Waste and are also summarized in
Appendix B of today's proposed rule.
The RACs represent 25 percent of the
Reference Doses (RfDs) for all pollutants
except lead; existing background levels
are assumed to account for the
remaining 75 percent of the RfD. The
lead RAG is defined as 10 percent of the
National Ambient air Quality Standard
(ANAQS) that has been promulgated for
lead under the Clean Air Act;
background exposures take up the
remaining 90 percent of the NAAQS
standard. These risk factors consider
only long-term effects and incorporate
standard EPA exposure assumptions
fe.g.i the average exposed individual
will weigh 70 kg, will inhale 20 cubic
meters of air each day, and will be
exposed continuously to the estimated
ambient pollutant concentration for 70
Population Exposed. Data on the
number of exposed individuals in the
^ icinity of each facility analyzed was
btained from U.S. Census data
available from the Office of Toxic
Substances' Graphical Exposure
Modeling System [GEMS). The
population data were first obtained in
the block grid/enumeration district level
and then summed to correspond with
the geographic segments used in the
dispersion modeling.
2. Results
Proposed Standards. Table 11 shows
the Agency's estimates of the effect of
today's proposed rule on MEI cancer
risk levels for metals at metal-burning
incinerators. The highest lifetime cancer
risk estimated in the baseline is roughly
5.0 X 10"5, with approximately 22 sites
(13 percent of all facilities burning_
metals) posing risks within this 10 5
range under baseline conditions. The
remaining 87 percent are estimated to be
currently operating under conditions
posing less than a one in 100,000 lifetime
risk of causing cancer to the maximum
exposed individual. The principal effect
of today's rule as it relates to
carcinogenic metals would be to cause
an estimated 22 facilities to reduce their
emission rates to levels at or below the 1
X 10"s risk level.
The estimated annual baseline cancer
incidence for the three carcinogenic
metals, aggregated across all 167 sites at
which EPA estimates such metals are
burned, is approximately 0.03 or roughly
two cases in 70 years nationwide. The
incidence results in a given year are
summarized in Table 12 by pollutant. As
shown, hexavalent chromium accounts
for over half of the predicted annual
cancer incidence, with cadmium and
arsenic contributing approximately 34
percent and 13 percent, respectively.
TABLE 11.—DISTRIBUTION OF INCINERA-
TOR FACILITIES BY ESTIMATED LIFETIME
MEI CANCER RISKS FOR INCINERATORS
BURNING METAL-BEARING WASTES: BE-
FORE AND AFTER COMPLIANCE J
1 Results for three metals: arsenic, cadmium, and
hexavalent chromium. Compliance based on meeting
a 1 OOE-05 MEI cancer risk level.
2 Based on available information, EPA estimates
that 167 or about 75 percent of the 227 facilities
burn metal-bearing wastes.
'Numbers may not sum to total because of
rounding.
TABLE 12.—ESTIMATED EXCESS ANNUAL
AND LIFETIME CANCER INCIDENCE FOR
INCINERATORS BURNING METAL-BEAR-
ING WASTES: BEFORE AND AFTER COM-
PLIANCE *
»>»Dtt«ficd Information on the dispersion
coeffidenls uwd in this risk assessment can be
found Ire Memorandum from Versar to TBS,
"Modeling Summary of Flat and Rolling Terrian
todnorator Site.." May 20,1987; Memorandum from
Veraar to TBS, "Modeling Summary of the High
Terrain Incinerator Site," June 12,1987;
Memorandum from Veraar to TBS. "Modeling
Re«uU« of Short-Term MH Concentrations for
HixinitaM Waste Incinerators", July 15.1S87.
Lifetime MEI
cancer risks
1.00E-02
1 OOE-03
1.0QE-04
1. OOE-05
1.00E-06
1.00E-07
1. OOE-03
1.00E-09
1.00E-10
1.00E-11
1.00E-12
Total facilities
burning
metals 3
Number of HW incinerator
facilities (percentage of total) *
Baseline
0
0
0
22 (13%)
28 (17%)
47 (28%)
36 (22%)
20 (12%)
8 (5%)
3 (2%)
3 (2%)
167— (100%)
After
compliance
0
0
0
0
50 (30%)
47 (28%)
36 (22%)'
20 (12%)
8 (5%)
3 (2%)
3 (2%)
167— (100%)
Pollutant
Arsenic
Cadmium
Chromium
(VI) :.
Total *
Number of cases per
year (percentage of
total)
Baseline
(percent)
0.005 (13)
0.012(35)
0.018 (52)
0.034
After
compli-
ance l
0.003
0.007
0.009
0.019
Cases per 70
years
Base-
line
0.318
0.824
1.248
2.39
After
compli-
ance
0.184
0.509
0.603
1.297
•Compliance based on meeting a 1.OOE-05 MEI
2 Numbers may not sum because of rounding.
After compliance with,the proposed
1 X 10~5 de minimis cancer risk level for
individual sites, EPA conservatively
estimates that the annual cancer
incidence for these incinerated metals
could be reduced from 0.03 to 0.02, or a
reduction from approximately two
lifetime cancer cases to one lifetime
cancer case nationwide in a 70-year
period. These calculations were based
on the risk reduction needed to meet the
proposed risk-based standards and may
have been understated. The .actual
environmental protection afforded by
the recommended control technologies
at each affected facility could be higher.
The risk assessment also estimated
exceedances of the RACs for lead and
HCI (short-term and long-term). The
predicted ambient air concentrations of
the other noncarcinogenic pollutants
analyzed (barium and mercury) did not
exceed the RACs for these two
pollutants at any of the sample facilities
modeled. Table 13 summarizes the
number of incinerator facilities for
which exceedances! of the lead and HCI
RACs are estimated. It also slows the
range of estimated percent reductions in
emissions necessary for these facilities
to meet the RACs. The number of
exceedances is highest for HCI (short-
term effects), followed-by lead. There is
also overlap among the facilities failing
the lead Or HCI RA Cs. Approximately 22
-------
*
~~' ———•• ••—••""™y"aai£:B!agias''"'-''f"'ia™=«agi»»i»nB»«!3c»n»—._. - •-•
of the 48 facilities are exceeding both
the lead and short-term HCI RACs. All
of the facilities hot complying with the
long-tenn HC1 RAG are also exceeding.
the lead RAG. Under 100 percent
compliance with the proposed risk-
based standards for lead and HC1, there
will be no exceedances of the RACs.
TABLE 13.—ESTIMATED INCREASED LIKE-
LIHOOD OF NONCANCER EFFECTS: EX-
CEEDANCES OF THE LEAD AND HGL
RACs BEFORE AND AFTER COMPLIANCE
TABLE 14.—DISTRIBUTION OF INCINERA-
i OR FACILITIES BY ESTIMATED LIFETIME
ME! CANCER RISK FOR INCINERATORS
BURNING METAL-BEARING WASTES: BE-
FORE AND AFTER COMPLIANCE
"
Pollutant
Lead
HCI (short-term)1
HCI (long-term)8 ,.
Number of HW
incinerator
facilities
exceeding the
RAC
Base-
line
Q-f
48
18
After
compli-
ance
' 0
0
Percent
reduction
in
emissions
neces-
sary to
comply
with RAC
5-78
20-99
Aggregate lifetime MEI
cancer risks
1.00E-02
1.00E-03 .•„.
1.00E-04.........
1.00E-05
1.QOE-06
I.OOE^-07
1.00E-08
1.00E-09..... .
1.00E-10
1.00E-11 ,
1.00E-12
Total facilities
burning metals '(").._
Number of HW incinerator
facilities (percentage of
total)2
Baseline
(percent)
0
0
0
22(13)
28(17)
47 (28)
36(22)
20(12)
8(5)
3(2)
3(2)
167 (100)
After
compliance
(percent)
0
0
0
0
0
87(58)
36(22)
20(12)
8(5)
3(3)
3(3)
167 (100)
RFA analysis. Those facilities exceeding
the 1 percent threshold for both
financial ratios calculated (COP and
GFO)wisre the primary focus of tiie ' .
RFA. The analysis was performed for
the subset of 82 facilities selected from
the Mail Survey; the results were
extrapolated to the population of 227
entities operating hazardous waste
incinerators.
EPA first identified which of the 82
hazardous waste incinerator facilities
evaluated in the Mail Survey could be
designated as small business entities In
particular, EPA used the. sales data in
Ward s Business Directory to determine .
which hazardous waste incinerators
were owned by entities that could
reasonably be classified as large.
Ward's lists all companies with annual
ih * ?2J?f th! 48 kcH'tfes do not comply with either
tha lead or the short-term HCI standard.
"All of the facilities unable to comply with HCI
standard also do not comply with ths lead standard.
Sensitivity Analysis. The alternative
cfe minimis risk standard evaluated in
the sensitivity analysis (1 x 10~9 will
have an impact only on the cancer risk
estimates for metals. Table 14 shows the
Agency's estimate of the effect of the
alternative standard on MEI cancer risk
levels for metals at metal-burning
incinerators. The more stringent
standard would cause an estimated 50
facilities to reduce their emission rates
for carcinogenic metals to levels at or
below a 1 x W~e risk level. This is an
increase of 28 additional facilities above
the proposed standard; however, six of
these facilities are already predicted to
need controls to reduce emissions of
noncarcinogenic metals.
As discussed above, the estimated
annual baseline, cancer incidence for the
three carcinogenic metals, aggregated
across all 167 sites at which EPA
estimates metals are burned, is
approximately 0.03 or roughly'two cases
nationwide in 70 years (see Table 15]. A
more stringent de minimis risk standard
of 1 x 10~6 would lower the estimated
annual cancer .incidence to
approximately 0.01 or about one case
nationwide in 70 years. These after :
compliance calculations were based on
the percent reduction in emissions
needed to meet the alternative risk-
based standard. • ~-
1 Results for three metals: arsenic, cadmium and
-T3&5S
2Bd °" avfage information, EPA estimates
of the
Numbers may not sum to total becauseof round-
TABLE 15.— ESTIMATED EXCESS ANNUAL
AND LIFETIME CANCER INCIDENCE FOR
INCINERATORS BURNING METAL-BEAR-
ING WASTES: BEFORE AND AFTER COM-
PLIANCE * - '
Number of cases per year
(percentage of total)
Pollutant
Arsenic
Cadmium......
Chromium
(VI)..
Total »..„...
Baseline
(percent)
0.005(13)
0.012 (35)
0.018 (52)
0.034 (iOO)
After
compli-
ance
0.001
0.004
0.005
.0.011
Cases per 70
years
Base-
line
0.318
0.824
1.248
2.39
After
Com-
pliance
0.103
0.299
0.368
0.771
cancerriskle^l etmg a 1x10"6 MEI
"Numbers may not sum because "of rounding.
G. Regulatory Flexibility Analysis
The Regulatory Flexibility Act (RFA)
requires Federal regulatory agencies to
evaluate tie impacts of regulations on
small entities. This section summarizes
EPA's methodology for conducting a
preliminary RFA analysis and the
results of that analysis. Based on the '
results, EPA has determined that today's
proposed rule will not have a significant
impact on a substantial number of small
entities. For the purpose of this analysis,
EPA assumed that all facilities were
single-established businesses/entities.
1, Methodology
The results of the economic impact
analysis were used as the basis for the
by Ward's as "large." In addition, EPA
determined whether an entity could
reasonably be classified as "large" in
the absence of financial data, e.g, a
university. If an entity could not be
classified as "large" on the basis of .
either Ward's or by inspection, EPA
assumed It was a "small" entity.
EPA then identified whether the
potentially affected "small" entities
accounted for a significant percentage of
all small entities owning hazardous
waste incinerators, or a significant
percentage of all small entities within a
given SIC code (i.e., industry). The total
number of entities-identified as "smalli'
for each SIC code was determined using
the SBA small plant employee size cut-<
otts and information from the U.S.
Census on the distribution of facilities
by employee size within each SIC
category. As a general criterion, the EPA
considers a proposed rule to have a
significant impact on a substantial
number of small entities if 20 percent of
small entities covered by the rule are
significantly affected by today's
proposed ride.
2. Results '|
— The majority of entities owning
hazardous waste incinerators (202
facilities, or 89 percent of all facilities)
were designated as "large," as shown in
Tables 16 and 17. The entities owning
the remaining 25 facilities were
identified as "small." The "large"
entities were predicted to incur
approximately 87 percent of the
estimated annualized compliance costs
(roughly $5.4 million) associated with
the proposed standards, and
approximately 90 percent of tie
estimated annualized costs (roughly $8 6
million) associated with the alternative'
standards evaluated in the sensitivity
-------
analysis. It is important to note that the
designation of a facility as a "small
entity" was based on a preliminary
review of readily available information.
However, this outcome appears
plausible from the standpoint that only
larger industrial operations would find it
economically feasible to construct and
operate on-size hazardous waste
incinerators,
E!LU'«J CODE 8S33-S9-M
-------
27,1990 //Propps?
17913
vi-ii.
DISTRIBUTION OF
SIC
Code
2231
2282
2421
2491
2511
2661
2813
2819
2821
2822
2824
2833
2834
2844
2851 .--
2861
2865
2869 ;
2873
2879
2891
2892
2899
2911
3079
3229
3339
3412
3433
3466 '
3483
3531
3672
3721
4953
7391
8062
8221
9661
9999
total1
ISums may
Large
Number of
Facilities
3
3 . .-.--
3
6~
•-.-?.'
3
8
-.-. • 20
3
-r - 3
3
' 3 ' .
3
• 3
3 • •
8
20
'• • 6
: 11.
3
' 3 . •
6
6
"3
3
3
3
3
3
- 3
3
18
14
J
6
3
• . -B . .
202
Table VJ-6- /O> ..
COMPLIANCE COSTS BY FACILITY
Entities Small
Compliance Number of
Costs Facilities
• $ 15,069 .
•" '.- 3
'34,184
13,285 . .
68.,202 '
28,567^ :
139,624
235,860
,324,298 3
27,930 •'-:'-•
30,992 ..3
82,272
258,781
131,017 ,
163,805
30,139 '."• .
: 210,607 ',.J
223,480 , ' : J
1,609,572
218,067
.- 25,463: .
-- - 18,405 . - -
52,337 ' ' -- .
90,874
3
'127,033
137,803 ,
• • . -."3 :
- 27,904
49,776 '3
97,646
82 , 562
170,465
17,006
196,612
134,785 - 3
27,438
34,987
16,131 :
207,004
$5,359,981",. -••'..' -25 "
SIZE AND -SIC
Entities
Compliance
Cdsts
$ 15,-685
576,640
15,069
.
91,961
.12,893 .
15,989
13,525
25,301
38,434
,$805,498
not total because of rounding.
-------
17914
Federal Register / Vol. 55, No. 82 /Friday. April 27,1990 / Proposed Rules
VI-12
DISTRIBUTION
SIC
Code
2231
2282
2421
2491
2511
2661
2813
2819
2821
2822
2824
2833
2834
2844
2851
2861
2865
2869
2873
2879
2891
2892
2899
2911
3079
3229
3339
3412
3433
3466
3483
3531
3672
3721
4953
7391
8062
8221
9661
9999
Total1
AM)
Large
Number of
Facilities
3
3
3
6
3
3
8
20
3
3
3
3
3
3
3
8
20
6
11
3
3
6
6
3
3
3
3
3
3
3
3
18
14
3
6
3
8
202
*Sums may not total
Tab.le Vf=T / ~f
OF COMPLIANCE COSTS BY FACILITY SIZE
SIC: SENSITIVITY ANALYSIS
Entities Small
Compliance Number of
Costs Facilities
$ 15,069
3
34,184
13,285
76,766
31,115
224,901 .
390,758
538,639 3
36,493
50,667 3
82,272
322 , 577
197,452
282,212
30,139
219,170 3
424,244 3
2,884,366
395,898
25,463
18,405
76,968
257,594
3
215,004
292,701
3
27", 9 04
49,776 3
121,486
86,809
296,262
25,570
217,108
312,616 3
27,438
52,113
16,131
274,389
$8,643,945 25
becaue of rounding.
Entities
Compliance
Costs
$ 15,685
576,640
15,069
267,244
12,893
15,989
13,525
48,234
58,434
$1,003,714
Biuma CODE esco-so-c
-------
The COP ratios did not exceed the 1
percent threshold for any of the entities
identified as "small" considering, either
the proposed or alternative standards
(see Table 18). The CFO ratio was in
excess of 1 percent for only three
"small" entities in SIC 2821 (with none
exceeding 2 percent) for the proposed
standards. These three entities represent
approximately 12 percent of all "small"
entities owning and operating hazardous
waste incinerators and 1 percent of all
designated small entities within the 2821
SIC Code."1
TABLE 18.—SMALL PLANT IMPACTS:
FINANCIAL RATIO TESTS
Analytical scenario
A. Proposed
Standards:
SIC 2821 „....
Total..
B. Sensitivity Analysis:
SIC 2821
SIC 2865....:...
Total
Estimated nationwide small
entities operating
hazardous waste
incinertprs (1)
Cost of
compli-
ance/
CQP>1%
0
d
0
0
0
Cost of
compli-
ance/
CFO>1%
3(1.6%)
3
3 (1.6%)
3(1.0%)
6
COP=Cost of Production.
CFO=Cash flow from operations.
(1) There is an estimated total of 25 small entities
operating harzardous waste incinerators.
In the sensitivity analysis, an
estimated six small entities were
predicated to face incremental costs
representing between 1 percent and 2
percent of net cash flow. These six small
entities account for approximately 24
percent of all small entities operating
hazardous waste incinerators. While
this appears to represent a substantial
number of small entities (i.e., greater
; than 20 percent), it is important to recall
that the CFO ratios for these small
entities never exceed 2 percent.
Based on these results, EPA concludes
that the today's proposed rule will
probably not pose a significant adverse
economic impact on a substantial
-number of small entities.
H. Paperwork Reduction Act
The information collection
requirements in this proposed rule have
been submitted for approval to the
Office of Management and Budget
1 * * It is important to note that the percentage of
small entities in SIC 2821 and 2865 affected by
today's proposed rule could be underestimated.
Many of the entities in each SIC assumed to be
small based on employee size may have large
annual revenues or be owned by large holding
companies. This determination could not be made
using available data..
(OMB) under the Paperwork Reduction
Act, 44 U.S.C. 3501 etseq. Reporting and
recordkeeping burden on the public for
this collection is estimated to average
628 hours per responser for reporting
and 20 hours per response for
recordkeeping.
If you wish to submit comments
regarding any aspect of this collection of
information, including suggestions for
reducing the burden, or if you would like
a copy of the information collection
request (please reference ICR #1559),
contact Rick Westlund, Information
Policy Branch, PM-223, U.S.
Environmental Protection Agency, 401M
St., SW., Washington, DC 20460 (202-
382-2745); and Marcus Peacock, Office
of Information and Regulatory Affairs,
Office of Management and Budget,
Washington, DC 20503. The final rule
: will respond to any OMB or public
comments on the information collection
requirements contained in this proposal.
ID. Pollution Prevention Impacts
These amendments would provide an
incentive to reduce the generation of
metal and chlorine-bearing hazardous
waste at the source given that the
proposed metals and HC1 emissions
controls would be implemented by
additional requirements attendant to the
disposal of those wastes, i.e., incinerator
feed rate limits for individual metals and
total chlorine. These requirements are,
in essence, tied to the economics of
disposing of given volumes of waste
since feed rates depend, in part, on the
volume of waste the incinerator
operator needs to burn. Thus, the metals
and HC1 controls proposed in this rule
do not simply require a percent
reduction in emissions, irrespective of
the volume and rate of incoming waste
streams. Rather, the controls are health-
based and, thus, provide limits on
emissions rates of metals arid :HC1 that
would be implemented by feed rate
limits. •
Waste generators who send then-
waste to commercial incinerators would
have the incentive to reduce the
generation of metal and chlorine-bearing
wastes because incineration fees are
likely to increase for such waste given
that the incinerator has a fixed metal
and chlorine feed rate allotment (due to
prescribed feed rates and incinerator
operating conditions). Wastes with
extremely high metals content may no
longer be acceptable for incineration in
many cases unless the waste generator
reduces the metals content'of the waste.
Any alternative for the disposal of such
wastes may be unavailable or the costs
of such treatment may be high enough to
create the incentive to reduce waste
generation rates at the source. This is a
typical scenario for pollution prevention
measures to be undertaken by waste
generators. -
^Similarly, generators who incinerate
their wastes on site also have the
incentive to reduce the generation of
metal land chlorine-bearing wastes given
that the proposed rule would provide a
fixed feed rate allotment for their
incinerator.
"•[ ." _
List of Subjects in 40 CFR Parts 260, 264
and 270
Hazardous material, Incorporation by
reference, Packaging and containers,
Reporting and record keeping
requirements, Security measures, Surety
bonds, Waste treatment and disposal,
Administrative practice and procedure,
Confidential business information,"
Harzardous materials transportation,
Hazardpus waste, Water pollution
control, Water supply. '
Dated: April 9,1990.
William K.Reffly,
Administrator.
Appendix A—Measurement of Metals
and Hydrogen Chloride
A-l: Metals Measurement Methods
General considerations of sampling
wastes ifor metals, the digestion of the
collected samples, and the analysis of
the resulting solution are described in
Chapter 3, Volume 1A of 'Test Methods
for Evaluating Solid Waste, Physical/
Chemical Methods," EPA Publication
SW-846 (incorporated by reference in
§.260,11). The current methods are
summariized below in Tables A-l and
A-2. ; • " ' " ' • '
. TABLE A-1.—-SAMPLE PREPARATION
METHODS
Methods
3010
3020
3050
'3040
Analysis procedure
CP, FLAA.;.™.
GFAA
FLAA, ICP or
GFAA.
ICP or FLAA.. „. J
:"• - I
Waste matrix
Aqueous only.
Sediment sludge,
soil, filter
participate
material, and
filter from stack
sampling train.
waxes.
nr rtn-, » recommended for virgin oils
or clean used oils. It is. not recommended for oils
that contain emulsions and particulates. Until EPA's
V '*9esti°
-------
17916
Federal Register / Vol. 55. No." 82'I Friday, April 27, 1990 /Proposed Rules
TABLE A-2.—ANALYSIS METHODS
Eampio
FtuoGas.,,,,: — >»..» "••••
Otlw S*mpl*t * ~™..« .-~» — i
Sampling procedure
Constituent
Total Metals • •»• \-—
Lead -
Sjjver
Antimony........
Lead '
ly>gr/»MfY ' , „..*,.
Analysis method
See Methods Listed Below.
7041
7060,b7061.b
6010,7080.
6010,7090,7091.
6010,7130,7131.
601 0; 71 90, 7191.
7195-7198."
6010,7420,7421.
7470,b7471.c
6010,7760.=
6010, 7841.
7040.
7060,b7061.b
6010, 7080.
6010,7090,7091.
6010,7130,7131.
6010,7190,7191.
7195-7198."
6010,7420,7421.
7470," 7471 .c
6010, 7760.*
6010,7841. - -
.TK~. ,*,~,,j.*r, (vn mnihorfs are for aoueous matrices only. EPA has nearly completed validation of a stack sampling methodology tor nexayaiem cnromium.
-M- * necessary.
«TOs moUwd InS digestion for all matrices (no digestion method from Table 111-12 is necessary).
* IndutfM wasta food, bottom ash and scrubber liquor.
The Multiple Metals Method
identified in Table A-2 is a method EPA
is proposing to determine emissions of
the 10 metals that would be regulated by
the proposed rule: antimony, arsenic,
barium, beryllium, cadmium, chromium,
lead, mercury, silver, and thallium. The
proposed method is described in U.S.
EPA, "Proposed Methods for Stack
Emissions Measurement of CO, O2,
THC, HCI, and Metals at Hazardous
Waste Incinerators, Vol. VI of the
Hazardous Waste Incineration
Guidance Series", November 1989. The
method uses a Method 5 train (40 CFR
Part 60, Appendix A) modified to
include the following impingers:
(1) empty (used for condensate
collection; may be omitted for a dry
source);
(2) 5 percent HNO3 and 10 percent
HiO*;
(3) same as 2;
(4) 4 percent KMnO4 and 10 percent
(5) same as 4; and
(8) silica gel (to protect pump and
meter). *
The document also provides alternate
methods and conditions under which
only a single metal analysis can be
performed.
A-2: Hydrogen Chloride
Measurement Methods
Methods of sampling and analysis of
the waste feed for chloride and stack
gas for HCI are described in detail in ,
EPA Publication No. SW-846, with
additional information provided in the
OSW Methods Manual. The latter
document discusses the acceptable
methods of sampling and analysis of
stack gases for hydrogen chloride.
Briefly, the sampling may be performed
using one of several trains. The EPA
Method 5 train (40 CFR part 60,
appendix A), or the semivolatile train
based on Method 0010 of EPA
Publication No. SW-846, may be used
by incorporating.a collection solution in
the second and third impingers. The
stack gas may also be sampled using a
specific HCI train incorporating the
game solution impingers.
Analysis of the gas sample may be
performed using Method 9251
Colorimetric Automated Ferricyanide or
9252 Titimetric Mercuric Nitrate as
described in Volume 1C, Chapters of
EPA Publication No. SW-848, or the Ion
Chromatography Method 300.0 as
described in "Method for Chemical
Analysis of Water and Waste," EPA
Publication No. EPA600/4-79-020 (NTIS
No. PB84-128677). Special
considerations including interferences,
cost, reliability, etc., that should be
considered in selecting the method to be
used are described in the Proposed
Methods Manual.
For the reasons set forth in the
preamble, it is proposed to amend title
40 of the Code of Federal Regulations as
follows: ,
PART 260—HAZARDOUS WASTE
MANAGEMENT SYSTEM: GENERAL
I. In part 260: .
1. The authority citation for part 260
continues to read as follows:
Authority: 42 U.S.C. 6905, 6912(a), 6921
Through 6927, 6930, 6934, 6935, 6937, 6938,
6939, and 6974.
2. In § 280.10, it is proposed to revise
the definition of "incinerator" and the .
introductory text of "industrial furnace",
and add in alphabetical, order,
definitions for "carbon regeneration
unit," "infrared incinerator", and
"plasma arc incinerator" to read as
follows:
§ 260.10 Definitions.
*,****.
Carbon regeneration unit means any
enclosed thermal treatment device used
to regenerate spent activated carbon.
Incinerator means any enclosed
device that:
(1) Uses controlled flame combustion
and neither meets the criteria for
classification as a boiler or carbon
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Federal : Register,./;
regeneration unit, nor is listed as an
industrial furnace: or
(2) Meets the definition of infrared
incinerator or plasma arc incinerator.
Industrial furnace means any of the
following enclosed devices that are
integral components of manufacturing
processes and that use thermal
treatment to accomplish recovery of
materials or energy: * * *
Infrared incinerator means any
enclosed device that uses electric
powered resistance heaters as a source
of radiant heat and which is not listed
as an industrial furnace.
Plasma arc incinerator means any
enclosed device using a high intensity
electrical discharge or arc as a source of
heat and which is not listed as an
industrial furnace. .
* * * * *
3. It is proposed to amend paragraph
(a] of § 260.11 by adding the following
reference in alphabetical order:
§260.11 References.
(a) * * *
"Risk Assessment Guideline for
Permitting Hazardous Waste Thermal
Treatment Devices (RAG)."
PART 261—IDENTIFICATION AND
LISTING OF HAZARDOUS WASTE
II. In part 261:
1. The authority citation for part 261
continues to read as follows:
Authority: 42 U.S.C. 6905, 6912(a), 6921,
6922, and 6937.
2. It is proposed to amend § 261.2 by
redesignating paragraph (d)(2) as (d)(3)
and adding a new paragraph (d)(2).
§ 261.2 Definition of solid waste.
(d) * * * ' • • . . •
(2) Secondary materials fed to a
halogen acid furnace that are identified
or exhibit a characteristic of a
hazardous waste as defined in subparts
C or D of this part.
PART 264—STANDARDS FOR
OWNERS AND OPERATORS OF
HAZARDOUS WASTE TREATMENT,
STORAGE, AND DISPOSAL
FACILITIES
• III. In part 264:
1. The authority citation for part 264
continues to read as follows:
Authority: 42 U.S.C. 6905, 6912(a), 6924, and
6925.
2. It is proposed to amend § 264.342 by
revising paragraphs (a) and (b)(l) to
read as follows:
§ 264.342 Principal organic hazardous
constituents (POHCs).
(a) All organic hazardous constituents
in the waste feed must be treated to the
extent required by the performance
standards of § 264.343(a).
(b) (1) Principal organic hazardous
constituents (POHCs) are those
compounds for which compliance with
paragraph (a) of this section shall be
demonstrated in a trial burn. One or
more POHCs shall be designated by the
Administrator for each waste feed in the
trial bum. POHCs shall be designated
based on the degree of difficulty of
incineration of the organic constituents
in the waste and on their concentration
or mass in the waste feed considering
the results of waste analyses submitted
with part B of the permit application.
POHCs are most likely to be selected
from among those compounds listed in
part 261, Appendix VIII of this chapter
that are also present in the normal
waste feed. However, if the applicant
demonstrates to the Regional
Administrator's satisfaction that a
compound not listed in Appendix VIII or
not present in the normal waste feed is a
suitable indicator of compliance with
paragraph (a) of this section, that
compound may be designated as a
POHC. Such POHCs need not be toxic
or organic compounds.
* * * .. * *
3. It is proposed to amend § 264.343 by
revising paragraph (c), redesignating
paragraph (d) as (gj and revising the
newly redesignated paragraph (g), and
adding new paragraphs (d), (e), (f), and
(h) to read as follows:
§264.343 Performance standards.
*****
(c) An incinerator burning hazardous
waste must not emit particulate matter
in excess of 180 milligrams per dry
standard cubic meter (0.08 grains per
dry standard cubic feet) when corrected
for the amount of oxygen in the stack
gas according to the formula:
14
E-Y
Where Pc is the corrected
concentration of particulate matter, Pm
is the measured concentration of
particulate matter, E is the percentage of
oxygen contained in the air used for
combustion, and Y is the measured
concentration of oxygen in the stack
gas, using the Orsat method for oxygen
analysis of dry flue gas, presented in ,
-part 60, appendix A (Method 3), of this
- Chapter. This correction factor is to be
used by all hazardous waste
incinerators. For incinerators using
ambient air for combustion, the value of
E will be 21, while for incinerators using
oxygen enriched air for combustion, the
value of E will be greater than 21.
(d) Carbon monoxide (l)(i) Tier I: ,
Except as: provided by paragraph
(d)(l)(ii) of this section, an incinerator
burning hazardous waste must be
operated so that carbon monoxide (CO)
levels (corrected to 7% oxygen, dry
basis) in the stack gas do not exceed 100
ppmv on an hourly rolling average basis.
(ii) Tier II: A hazardous waste
incinerator may be operated at CO
levels higher than those provided by
paragraph (d)(l)(i) of this section
provided the owner or operator
demonstrates that emissions of total
hydrocarbons (THC) at that higher CO
level do not pose an unacceptable
health risk to the maximum exposed
individual For the purpose of this
demonstration, THC must be monitored
continuously during the trial burn in
accordance with methods specified in
"Test Methods for Evaluating Solid
Waste, Physical/Chemical Methods,"
EPA publication SW-846 as
incorporated by reference in § 260.11.
For purposes of this subpart, THC will
be considered to pose acceptable health '
risk when: .
(A) The maximum hourly average
THC emissions rate during the trial burn
does not exceed the THC Screening '. ^
Limits identified in the "Risk
Assessment Guideline for Permitting
Hazardous Waste Thermal Treatment
Devices" (RAG) as incorporated by
reference in § 260.11; or
(B) When the owner or operator
demonstra.tes by site-specific dispersion
modeling that THC emissions will not
result in an increased lifetime cancer
risk to the maximum exposed individual
of more than 10~5 using procedures
prescribed in the RAG (incorporated by
reference in § 260.11).
(2) CO limits will be established in the
permit using one of the following . ,
formats: ,.
(i) Hourly rolling average format,. ,
where the permitted CO level is 100
ppmv for Tier I and the average of the
CO levels occurring during the trial burn
for Tier II; or
(ii) Cumulative hourly time above
limit formal, where two CO limits will
be specified—one which cannot be.
. exceeded at any time and the other,
which can be exceeded only for a -
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Federal Register / Vol. 55, No. 82 / Friday, April 27,1990 / Proposed Rules
specified time in any clock hour. These
CO limits, and time of exceedance in
any hour, shall be established to ensure
that the total permitted CO emissions do
not exceed those that would be allowed
under the hourly rolling average format
in any hour of operation.
(3) Correction factor for oxygen, (i)
When the oxygen content in the stack
gas differs from 7 percent, measured CO
levels must be corrected for the actual
amount of oxygen in the stack gas
according to the formula:
COe«COm X'
14
E-Y
whore COC is the corrected
concentration of CO in the stack gas,
COffl is the measured CO concentration
measured in accordance with "Test
Methods For Evaluating Solid Waste
Physical/Chemical Methods," EPA
Publication SW-846 as incorporated by
reference in 1200.11, E is the percentage
of oxygen contained in the air used for
combustion, and Y is the measured
oxygen concentration in the stack gas
using the Orsat method of oxygen
analysis in part 60, Appendix A (Method
3) of this Chapter if oxygen is not
monitored continuously, or using the
method proscribed in 'Test Methods for
Evaluating Solid Waste Physical/
Chemical Methods," EPA Publication
SW-848 is incorporated by reference in
§ 200.11, when oxygen is monitored
continuously. This correction procedure
is to be used by all hazardous waste
incinerators. For incinerators using
ambient air for combustion, the value
for E will be 21. For incinerators using
oxygen-enriched air, the value for E will
be greater than 21.
(ii) For purposes of compliance with
(he hourly roiling average format of
paragraph (d)(2)(i) of this section, the
stack gas oxygen level, correction factor,
and the corrected CO value shall be
determined continuously. For
compliance with the cumulative time
above limit format of paragraph (d)(2)(ii)
of this section, the appropriate stack
oxygen level and the CO correction
factor shall initially be determined
during the trial burn (or by data in lieu
of a trial burn] and, at a minimum,
annually thereafter. The Regional
Administrator may specify in the permit
more frequent determinations if
necessary to ensure that the correction
factor is accurate. That correction factor
shall be applied continuously to provide
corrected CO values continuously. .
(4) The CO limits provided by this
section are based on dry stack gas.
When instruments that measure CO on
a wet basis are used, a correction factor
shall be used to convert the measured
' value to a dry basis. This correction
factor shall initially be determined
during the trial burn and annually
thereafter unless otherwise specified in
the permit.
(e) Metals. (1) The owner and
operator must comply with the metals
controls provided by paragraphs (e)(2J,
(e)(3), or (e)(4) of this section.
(2) Feed Rate Screening Limits, (i) For
the carcinogenic metals arsenic,
cadmium, chromium, and beryllium, the
sum of the ratios of the actual feed rate
in Ibs/hr to the Feed Rate Screening
Limit for all the metals shall not exceed
1.0, as determined by the following
equation:
Actual Feed Ratei
Feed Rate Screening Limitt
where:
n=number of carcinogenic metals
Actual Feed Ratet=the actual feed rate for
metal "i", in Ib/hr.
Feed Rate Screening Limiti=the limit
provided in the RAG for metal "i", in lb/
hr.
The Screening Limits are specified in the
RAG, incorporated by reference in
§ 260.11, for the applicable effective
stack height, terrain type and urban or
rural land use classification.
(ii) For each of the noncarcinogenic
metals antimony, barium, lead, mercury,
silver, and thallium, the actual feed rate
in Ib/hr shall not exceed the Feed Rate
• Screening Limits specified in the RAG
(incorporated by reference in § 260.11)
for the applicable effective stack height,
terrain type, and urban or rural land use
classification.
(3) Emissions Screening Limits, (i) For
the carcinogenic metals arsenic,
cadmium, chromium, and beryllium, the
sum of the ratios of the actual emission
rate to the Emissions Screening Limit for
all the metals shall not exceed 1.0, as
determined by the following equation:
where:
n=number of carcinogens
Predicted Ambient Concentration = the
maximum off-site annual average ground
level concentration for metal "i", in ug/
m3, at the lO"8 risk level.'
Total chromium emission rates
measured in accordance with "Test
Methods for Evaluating Solid Waste;
Physical/Chemical Methods," EPA
Publication SW-846, as incorporated by
reference in § 260.11 are to be used for
this determination, unless the
applicant's sampling and analysis
procedures are capable of reliably
determining hexavalent chromium
emission rates to the satisfaction of the
Administrator.
(ii) For each of the noncarcinogenic
metals, antimony, barium, lead, mercury,
silver, and thallium, the predicted
maximum annual average off-site
ground level concentration shall not
exceed the Reference Air
Concentrations provided by the RAG.
(iii) Conformance with the
requirements provided by this
paragraph is demonstrated by stack
emissions testing in accordance with the
Multiple Metals Method in "Test
Methods for Evaluating Solid Waste;
Physical/Chemical Methods," EPA '
Publication SW-846, as incorporated by
reference in § 260.11-and 40 CFR 60
Reference Methods 1-5, and dispersion
modeling in accordance with EPA's
"Guideline on Air Quality Models
(Revised)" (see § 270.6).
(5) For facilities with more than one
stack handling emissions from the
burning of hazardous waste in an
incinerator, boiler, or industrial furnace,
aggregate emissions from all such stacks
will be considered in demonstrating
compliance with paragraph (d) of this
section according to procedures
prescribed in the RAG.
(f) Hydrogen chloride. (1) The owner
and operator must comply with the total
chlorine or hydrogen chloride (HCI)
controls provided by paragraphs (f)(2),
tf)(3), or (f)(4) of this section.
(2) Feed Rate Screening Limits. The
actual feed rate of total chlorine in Ib/hr
shall not exceed the Feed Rate
Screening Limits provided in the RAG
(see § 260.11) for the applicable effective
stack height and terrain type, as defined
in the RAG.
Actual Feed Rate,
Emissions Screening Limit)
< 1.0
where:
n = number of carcinogenic metals
Actual Emission Ratei = the emission rate
measured during the trail burn or
provided in lieu of the trail burn for
metal "i", in g/s.
Emissions Screening Limiti = the limit
provided in the RA.G for metal "i", in g/s.
The Screening Limits are specified in the
RAG (incorporated by reference in ,
§ 260.11) for the applicable effective
stack height, terain type and urban or
rural land use classification. Total
chromium emission rates measured in
accordance with "Test Methods for
Evaluating Solid Waste; Physical/
Chemical Methods," EPA Publication
SW-846, as incorporated by reference in
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Federal Register / Vol. 55, No. 82 /.Friday, April 27,1990 / Proposed-Rules
17919
§ 260.11 are to be used for this
determination unless the applicant's
emissions sampling and analysis
procedures are capable of reliably
determining hexavalent chromium
emissions rates to the satisfaction of the
Administrator; and
(ii) For each of the carcinogenic
metals antimony, barium, lead, mercury,
silver, and thallium, the actual emission
• rate shall not exceed the Emissions
Screening Limits provided in the RAG
(incorporated by reference in § 260.11)
for the applicable effective stack height,
terrain type, and urban versus rural land
use classification.
(iii) Metals emissions must be
measured in accordance with the
Multiple Metals Method in "Test
Methods for Evaluating Solid Waste;
Physical/Chemical Methods," EPA
Publication SW-846, as incorporated by
reference in §260.11 and 40 CFR 60
Reference Methods 1-5.
(4) Site-specific risk analysis, (i) For
the carcinogenic metals arsenic,
cadmium, chromium and beryllium, the
sum of the ratios of the predicted
maximum off-site annual average
ground level concentration to the Risk-
Specific Dose for all carcinogenic metals
shall not exceed 1.0, as determined by
the following equation.
Predicted Ambient
Concentration!
Risk Specific
< 1.0
(3) Emissions Screening Limits. The
emission rate of HC1 in g/s shall hot
exceed the Emissions Screening Limits
provided in the RAG for the applicable
effective stack height and terrain type. -
(4) Site specific risk analysis. HC1
emissions shall not result in an
exceedance of the 3-minute exposure
Reference Air Concentration (RAG) or
the annual exposure RAG provided by
the RAG. Conformance with this
standard shall be demonstrated as
provided by paragraphs (e)(4) {iii) and
(iv) of this section. , •
(5) For facilities with more than one
stack handling emissions from the
burning of hazardous waste in an
incinerator, boiler, or industrial furnace,
aggregate emissions from all such stacks
will be considered in demonstrating
compliance with paragraph (e) of this
section according to procedures
prescribed in the RAG.
(g) For purposes of permit
enforcement, compliance with the
operating requirements specified in the
permit (under § 264.345) will be regarded
as compliance with this section.
However, evidence that compliance
with those permit conditions is
insufficient to. ensure compliance with :
the performance requirements of this
section may be "information" justifying
modification, revocation, or reissuance
of a permit under § 270.41 of this
chapter.
(h) The Feed Rate and Emission
Screening Limits for metals and HC1
provided by paragraphs (e) and (f) of
this section, and the Emission Screening
Limits for THC provided by paragraph
(d) of this section may riot be protective
in the following situations:
(1) Facility-is located in a narrow
valley less than 1 km wide; or
(2) Facility has a stack taller than 20m
and is located such that the terrain rises
to the physical stack height within 1 km
of the facility; or
(3) Facility has a stack taller than 20m
and is located within 5 km of the
shoreline of a large body of water (such
as an ocean or large lake); or
(4) The facility property line is within
200m of the stack and the physical stack
height is less than 10m; or
(5) On-site receptors are of concern,
and the physical stack height is less
than 10m.
For these cases, and for any other
reasons deemed appropriate, the
Regional Administrator may, at his
discretion, require the owner/operator
to submit a site-specific air quality
dispersion analysis consistent with •
"Guideline on Air Quality Models
(Revised)," EPA Publication 450/2-78-
027R as incorporated by reference in
§ 270.6 of this chapter. Where such an
analysis is required, the determination
of source limits shall be iri'accordance
with the procedures employed for
establishing the limits specified by this
section. ,
4. It is proposed to amend § 264.345 by
revising paragraph (a) and adding text
to the end of paragraph (e) to read as
follows:
§ 264.345 Operating requirements.
* * -. * * *
(a) An incinerator must be operated in
accordance with operating requirements
specified in the permit whenever there is
hazardous waste in the incinerator.
These will be specified on a case-by-
case basis as those demonstrated (in a
trial burn or in alternative data as
specified in § 264.344(b) and included
with part B of the facility's permit
application) to be sufficient to comply
with the performance standards of
§ 264.343.
.* *•.*-* *
(e) * * * When the hazardous waste
feed is cut off, the temperature in the
(secondary) combustion chamber must
be maintained and emission control
equipment must continue1 to function as
specified in: the permit until all residual
solids exit the combustion chamber. For
cases wheniwaste feed cutoff occurred
because of exceeding the CO limits, the
waste feed imay be resumed only after
the CO levels are brought down to
permitted levels.
. * ' * «!' * *
5. It is proposed to revise the heading
of § 264.347 and amend it by revising
paragraphs (a) and (c); revising and
redesignating paragraph (d) as (e); and
•adding new paragraph (d) to read as
follows: j
§ 264.347 Monitoring, inspections, and
reporting requirements.
(a) The owner or operator must
conduct, as a minimum, the following
monitoring while incinerating hazardous
waste: . •'
(1) Combiistion temperature and the
indicators oiF combustion gas velocity,
air pollution control device parameters,
and other psirameters as specified in the
facility permit as necessary to ensure
the performance standards of § 264.343 •
are met, musit be continuously monitored
by equipment that records the
parameters at least every 30 seconds.
(2) CO must be monitored and
recorded on a continuous basis in
accordance with SW-846 (as
incorporated in § 260.11) at a point in
the incinerator downstream of the
combustion zone and prior to release to
the atmosphere.
(3) As a part of the permit renewal
process or upon request by the Regional
Administrator, sampling and analysis of
the waste and exhaust emissions must
be conducted to verify that the operating
requirements established in the permit
achieve the performance standards of
§ 264.343. ;;
* * ,* i ".*..-*.
(c) The automatic waste cutoff system
and associated alarms must be tested at
least weekly to verify operability, unless
the applicant demonstrates to the
Regional Administrator that weekly
inspections will unduly restrict or upset
operations and that less frequent
inspection will be adequate. At a
minimum, operational testing must be
conducted monthly.
(d) The continuous monitors required
under § 264.347{a) must be calibrated at
least weekly, unless the applicant
, demonstrates! to the Regional ;
Administrator that weekly calibrations
will unduly restrict or upset operations
and that less frequent calibration will be ,
adequate. At a minimum, they must be
calibrated monthly. . "
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Federal Register / Vol. 55, No. 82 /Friday, April 27,1990 / Proposed Rules
(c) The monitoring and inspection
data must be recorded and the records
must be placed in the operating log
required by § 254.73. The operator must
record in the operating log whenever the
hazardous waste feed is cut off in
accordance with § 264.345(e). The record
must include date, time and
circumstances of each cut off and the
action the operator took to address the
problem. Quarterly reports of automatic
waste feed cutoffs, the circumstances of
the cutoffs, and any noncompliance
incidents must be submitted to the
Administrator within 30 days of the end
of the applicable reporting quarter.
PART 270—EPA ADMINISTERED
PERMIT PROGRAMS: THE
HAZARDOUS WASTE PERMIT
PROGRAM
IV. In part 270:
1. The authority for part 270 continues
to read as follows:
Authority: 42 U.S.C. 6905. 6912, 6924. 6925,
0927,6939 and G974.
2. It ia proposed to amend § 270.6 (a)
by adding a new reference in
alphabetical order to read as follows:
§ 270.6 References.
(a) « * *
"Guidisline on Air Quality Models
(Revised)," EPA Publication Number 450/2-
78-027R (OAQPS Guideline No. 1.2-080),.
available from National Technical
Information Service. Springfield, Virginia,
Order No. PB 86-245288.
*****
3. It is proposed to amend § 270.19 by
revising paragraph, (a) introductory test,
and paragraphs (cHl)(iii), (c)(3), (c)(6)(ii),
and (c)(7), by removing paragraph
(c){6){vii) and redesignating paragraphs
(c)(e) (viii) and (be) as (c)(6) (vii) and
(viii), respectively, and by adding
paragraphs (c)(9), (e) and (f) to read as
follows:
§ 270.19 Specific Part B Information
requirements for Incinerators.
*****
(a) When seeking an exemption under
§ 204.340 (bj or (c) of this chapter
(ignitable, corrosive, or reactive wastes
only), the applicant must perform and
submit an analysis of representative
samples of all waste streams for which
the applicant Is seeking an exemption,
for all the part 281, appendix VIII
constituents which would reasonably be
expected to be in the waste. The
constituents excluded from analysis
must be identified, and documentation
provided to support that they would not
reasonably be expected to be In the
waste. The applicant must also submit,
as appropriate:
* . * * * * •
•(0, * * *
(1) * * *
(iii) An identification of any
hazardous metals and hazardous
organic constituents, listed in. part 261,
appendix VIII, of this chapter, and total
chlorine which are present in the waste
to be burned, except that the applicant
need not analyze for constituents listed
in part 261, appendix VHlrof this
chapter which would reasonably, not be
expected to be found in the waste. The
constituents excluded from analysis
must be identified and the basis for their
exclusion stated. The waste analysis -
must rely on analytic techniques
specified in "Test Methods for
Evaluating Solid Waste, Physical/
Chemical Methods," (EPA Publication
SW-846 as incorporated by reference in
§ 260.11 and referenced in 40 CFR part
261, appendix III), or their equivalent.
*****
(3) A description and analysis of the
waste to be burned shall be compared
with the waste for which data from
operations or trial burns are provided to
support the contention that a trial burn
is not needed. The data should include
the items listed In paragraph (c)(l) of
this section. This analysis should
specify the POHCs, metals, and total
chlorine which the applicant has
identified in the waste for which a
permit is sought, and any differences
therefrom for the waste for which the
trial burn data are provided.
******
(6) * * *
(ii) Total waste feed rate, individual
metal feed rates (specified separately
for liquid (pumpable} wastes, solid
wastes, and organometals), and total
chlorine feed rate.
*****
(7) Such supplemental information as
the Director finds necessary to achieve
the purposes- of this paragraph. This
information includes, but is not
necessarily limited to:
(i) Physical stack height. >
(ii) Stack flue gas temperature.
(iii) Topographical data up to a
distance of 5 km around the stack, and -
land use data within a 3 km radius of
. the stack, including maps and aerial
photographs.
(iv) Stack gas flow rate.
* w w , M: *
(9) Information that the Director finds
necessary to demonstrate compliance
• with the Feed Rate Screening Limits,
Emissions Screening Limits, or Site- •
Specific Risk Analysis standards for
metals and HC1 at levels which do not
pose an unacceptable risk to human
health and the environment and which
may include the following data:
(i) For Emissions Screening Limits and
Site-Specific Risk Analysis, metals and
HC1 emission rates from the stack for
the facility whose data is proposed to be
used in lieu of the trial burn.
(ii) For Site-Specific Risk Analysis,
predictions of maximum, annual average
off-site ground level concentrations (on-
site concentrations must be considered
if individuals reside on'site) for metals:
and HC1 for the facility seeking the
permit, as well as:
(A) Meteorological data;
(B) Rationale for air dispersion model
selection;
(C) Topographic considerations.
(iii) A comparison of the actual
emission rates from the facility whose
data is beingproposed to the expected
emission rates of the facility seeking the
permit.
*****
(e) Applicants seeking to be permitted
for burning of wastes containing metals
or chlorine must submit information or
documentation needed for the Director
to determine whether the incinerator is
situated in complex or noncomplex
terrain, whether the incinerator is
located in an urban or rural land use
area as defined in the RAG, and any
other information necessary to set the
appropriate metals at HC1 permit
conditions. The applicant must set forth
the methodology and all information
used for the determination.
(f) Applicants seeking to be permitted
under the Site-Specific Risk Analysis
provisions of § 264.343 for THC, metals
and total chlorine must submit a
dispersion modeling plan with part Bof
the permit application. The Director will
review the plan forconformance with
the "Guideline on Air Quality Models
(Revised)" (Incorporated by reference,
see 5 270.6). The Director will either
approve -the modeling plan or determine ,
that an alternate or supplementary plan
is appropriate. After completion of the
trial burn to measure metals, THC and
HCI emission rates, the owner or
operator must conduct dispersion
modeling according to the approved
plan and submit the results to the
Director In the trial burn report. The
Director will determine whether the
results are in confbrmance with, the
requirements of § 264.343 (d), (e), and (f)
of this chapter and will establish
appropriate operating requirement's aa-
required by | 264.345 of this chapter.
* * * * - *
5. It is proposed to amend $ 270:62 bv
revising paragraphs (b](2)(i](C),
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55' No" 82 ^ Fri<%VApril 27,1990, / Proposed .Rules
17921
(b)(8), (c) introductory text, and (c)(l);
by adding new paragraphs (b)(2)(i)(E),
and (b)(2)(ii)(K), and redesignating
paragraph (b](10) as (b)(llj and revising
it and adding a new paragraph (b)(10) to
read as follows:
§270.62 Hazardous waste incinerator
permits.
* * * * *
(b) * * * .
(2) •* * * '
(i)
(C) An identification of any hazardous
metals, hazardous organic constituents
listed in part 261, appendix VIII of this
chapter, and total chlorine, which are
present in the waste to be burned,
except that the applicant need not
analyze for constituents listed in part
261, appendix VIII, of this chapter which
'would not reasonably be expected to be
found in the waste or are easier to
destroy than the most difficult POHC to
be tested in the trial burn. The
constituents excluded from analysis
must be identified, and the basis for the
exclusion stated. The waste analysis
must rely on analytical techniques
specified in "Test Methods for
Evaluating of Solid Waste, Physical/
Chemical Methods," EPA Publication
SW-846 as incorporated by reference, in
§ 260.11 or their equivalent.
(D) An approximate quantification of
the hazardous constituents including
metals and total chlorine identified in
the waste, within the precision produced
by the analytical methods specified in
"Test Methods for Evaluating Solid
Waste, Physical/Chemical Methods,"
EPA Publication SW-846 as
incorporated by reference, in § 260.11, or
their equivalent.
(E] Total chlorine concentration of the
waste in the form and composition in
. which it will be burned.
(II) *.*'.-..
(F) Description of automatic waste "
feed cut-off system(s), and how they are
connected to any thermal relief valve or
bypass system.
(G) Stack gas monitoring, pollution
control equipment, and heights of all
stacks or combustion gas discharge
vents, measured from ground level.
****-*_
(K) Location and description of any
" bypass systems, and any backup or
redundant equipment to limit the
number of bypass events.
* * * , * * '
(vii) Procedures for rapidly stopping
waste feed, shutting down the
incinerator, maintaining temperature in
the combustion chamber until all waste
exit the incinerator, and controlling
emissions in the event of an equipment
malfunction or activation of. any thermal
relief valve or other bypass system
including calculations demonstrating
that emissions will be controlled during
such an event (sufficient oxygen for
combustion and maintaining negative
pressure), and the procedures for
executing the "contingency plan"
whenever a relief valve is used, thus
causing an emergency release of
emissions.
****.*
(4) Based on the waste analysis data
in the trial burn plan, the Director will
specify as trial Principal Organic
Hazardous Constituents (POHCs), those
constituents for which destruction and
removal efficiencies must be calculated
during the trial burn.
(i) These trial POHCs will be specified
by the Director based on his estimate of
the difficulty of incineration of the
constituents identified in the waste
analysis, their concentration or mass in
the waste feed, and, for wastes listed in
part 261, subpart D, of this chapter, the
hazardous waste organic constituent or
constituents identified in appendix VII
of that part as the basis for listing.
(ii) The use of a POHC surrogate as
proved by § 264.342(b)(l) of this chapter
may be appropriate in certain
circumstances based on the Director's
estimate of the difficulty of chemical
analysis of the waste, the low
concentrations of POHCs in the waste,
the low stability of waste POHCs in the
waste, or other appropriate factors. Such
surrogates need not be organic, toxic or
present in the waste. The Director may
approve the use of a POHC surrogate
provided it is suitable based on the
performance standard of § 264.343(a),
the composition of the wastes to be
incinerated, and the sampling and
analysis requirements.
* * * * *
(6)* *•*"
(i) A quantitative analysis of the trial
POHCs, total chlorine, and metals in the
waste feed to the incinerator.
(ii) A quantitative analysis of the
exhaust gas for the concentration and
mass emissions of the trial POHCs
(POHC surrogates), oxygen (O2), and, as
appropriate, metals and hydrogen
chloride.
(iii) A quantitative analysis of the
scrubber water (if any), ash residues,
and other residues, for the purpose of
estimating the fate of the trial POHCs,
HC1, and metals, as appropriate.
* * * * *
(v) A computation of the total chlorine
feed rate and, if applicable, the HC1
emission rate, in accordance with
§ 264.343(f) of this chapter.
* * *;' * * *
(viii) A cdntinous measurement of
temperature, combustion gas velocity,
and all waste feed rates.
•(ix) A continuous measurement in the
exhaust gas .of carbon monoxide (CO)
and oxygen (O2) (as required), and THC
-. emissions if complying with 40 CFR
264.343(d)(l)(ii) in lieu of 40 CFR
264.343(d)(l]i(i).
* * *'. * * . • .
(8) All data collected during any trial
burn, and subsequent analyses of all
trial burn samples including assurance
and control (QA/QC) data; must be
submitted to the Director within 90 days
of completion of the trial burn.
* • * " * ; ' * *
(10) All trial burn runs for which
permit conditions will be established
must be passed (i.e., conformance must
be demonstrated for all performance
standards provided by § 246.343 of this
chapter for all runs). A minimum of
three runs must be passed for each set
of permit conditions. One of the three
runs may be Disregarded if the Director
believes there is sufficient reason.
(11) Based on the results of the trial
burns, the Director shall set the
operating requirements in the final
permit according to § 264.345 of this
chapter. The permit modification shall
proceed as a-minor modification
according to § 270.42.
(c) For the purposes of allowing
operation of .a new hazadous waste
incinerator following completion of the
trial burn and prior to final modification
of the permit conditions to reflect the
trial burn results, the Director may
establish permit conditions, including
but not limited to allowable waste feeds,
emission rate's, and operating conditions
sufficient to meet the requirements of
§ 264.345 of this chapter, in the permit to
a new hazardous waste incinerator.
These permit conditions will be effective
for the minimum time required to
complete sample analysis, data
computation, and submission of the trial
burn results by the applicant, and
modification of the facility permit by the
Director. ; •
(1) Applicants must submit a
statement with the permit application,
which identifies the conditions
necessary to operate in compliance With
the performance standards of § 264.343
of this chapter, during this period. This
statement should include, at a minimum,
restrictions on waste constituents, waste
feed rates, emission rates, and operating
parameters in § 264.345 of this chapter.
[FR Doc. 90-8821 Filed 4-1-90; 8:45 am]
BILLING CODE 656D-50-M
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