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                ENVIRONMENTAL PROTECTION AGENCY

                40 CFR Pans 260, 261, 264, 265, 266,. 270, and 271
                              
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EFFECTIVE DATE: Ibis final rule is effective on [date six months from promulgation].

Technical corectioos to section 270.73 are effective immediately.

ADDRESSES: The official record for this rulemaking is identified as Docket Numbers F-

87-BBFP-FFFFF and F-89-BBSP-FFFFF, and is located in the EPA RCRA Docket,

Room 2427t 401M Street SW., Washington, DC 20460. The docket is available for

inspection irono 9 ajn. eo4 pm., Monday through Friday, except on Federal holidays. The

public must make an appoinxment to review docket materials by calling (202) 475-9327.

The public may copy up to 100 pages from the docket at no charge. Additional copies cost
$.15 per page.


      FOR FURTHER INFORMATION CONTACT: For general information contact

the RCRA Hotline at: (800) 424-9346 (toll-free) or (202) 382-3000 locally. For

information on specific  aspects of this final rule, contact Dwight Hhistick, Office of Solid
Waste (OS-322W), U.S. Environmental Protection Agency, 401 M Street SW.,

Washington, DC 20460, (703) 308-8460.


SUPPLEMENTARY INFORMATION:

Preamble Outline

PART ONE: BACKGROUND
  I. Legal Authority
  II. Overview of the Final Rule
   A. Controls for Emissions of Organic Compounds
   B. Controls for Emissions of Toxic Metals
   C. Controls for Emissions of Hydrogen Chloride and Chlorine Gas
   D. Emission Standard for Paniculate Matter
   E. Permitting Procedures
   F. Controls During Interim Status
   G. Units Exempt from Air Emissions Standards
   H. Pollution Prevention Impacts
  m. Relationship to Other Rules
   A. Regulations to be Promulgated Under the New Clean Air Act
   B. April 27,1990 Proposed Incinerator Amendments
   C July 28,1990 Proposed Amendment to Definition of Wastewater Treatment Unit to
     Exempt Sludge Dryers
   D. Land Disposal Restriction Standards
PART TWO: DEVICES SUBJECT TO REGULATION
  I. Boilers
  U. Industrial Furnaces
   A. Cement Kilns
   B. Light-Weight Aggregate Kilns
   C. Halogen Acid Furnaces
     1. Current Practices        YJ,m, -j^,.^^

                     H^SA HOr- "03Tuft -1 JA7K3HH011 < VR

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     2. Designation of HAFs as Industrial Furnaces
   D, Smelting, Mslring, and Refining Furnaces Bumine,Hazardous Waste to Recover
     Meals                                    /
PART THREE: STANDARDS FOR BOILERS AND/INDUSTRIAL FURNACES
  BURNING HAZARDOUS WASTE           ,'
  I. Emission Standard for Paniculate Matter
   A. Basis for Final Rule
     1. Alternatives Considered
     2. Basis for Standard
   B. Into im Status Compliance Procedures
   C. Implern^itatioa
  IL Controls for Emissions of Toxic Organic Compounds
   A. DRE Standard
     1. Selection of POHCs for DRE Testing
     2. Use of POHC Surrogates
     3. Waiver of DRE Trial Bum for Boilers Operating Under the Special Operating
      Requirements
   B. PIC Controls
     1. Use of a CO Limit to Control PICs
     2. Tier I PIC Controls:  100 ppmv CO limit
     3. Tier n PIC Controls: Limits on CO and HC
     4. Special Requirements for Furnaces
     5. Special Considerations for Cement Kilns
   C. Automatic Waste Feed Cutoff Requirements
   D. CEM Requirements for PIC Controls
   E. Control of Dioxin and Furan Emissions
  ffl. Risk Assessment Procedures
   A. Health Effects Data
     1. Carcinogens
     2. Noncarcinogens
   B. Air Dispersion Modeling
     1. Option for Site-Specific Modeling
   ~  2. Terrain-Adjusted Effective Stack Height
     3. Conservatism in Screening Limits
     4. GEP Stack Height
     5. Plume Rise Table
     6. Compliance by Manipulating Effective Stack Height
     7. Effect of HC1 Emissions on  Acid Rain
     8. Building Wake Effects
   C Consideration of Indirect Exposure and Environmental Impacts
     1. Indirect Exposure
     2.Non-human Health Related Environmental Impacts
   D. Acceptable Risk Level for Carcinogens
   E. Use of MEI and Consideration of Aggregate Risk
   F. Risk Assessment Assumptions
  IV. Controls for Emissions of Toxic Metals
   A. Background Information
     1. Metals Standards under Other Statutes
     2.1987 Proposed Rule
     3.1989 Supplement to Proposed Rule
   B. How the Standards Work
     1. Tier HI Standards
     2. Tier II Standards
     3. Tier I Standards

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  C. Implementation
   1. Tier I Implementation
   2. Tier B Implementation
   3. Tier in Implementation
   4. Special Requirements for Furnaces that Recycle Collected Paniculate Matter
   S Trial Burns
   6. Monitoring and Analysis Requirements
  D. Interim Status Compliance Requirements
V. Controls for Emissions of Hydrogen Chloride and Chlorine Gas
  A. Background Information
  B. Response to Comments
   LShon-TennHClRAC
   2. Need for Cl2 Controls
   3. HCI Emission Test Procedures
   4. Technology-Based HCI Controls
  C. Implementation
   1. Emissions Testing
   2. Waste Analysis
   3. Interim Status Compliance Requirements
VI. Nontechnical Requirements
VII. Interim Status Standards
  A.Certification Schedule
   1. Certification of Precompliance
   2. Certification of Compliance
   3. Recertification
   4. Failure to Comply with the Certification Schedule
   S. Development of the Certification Schedule
  B. Limits on Operating Parameters
  C. Automatic Waste Feed Cutoff
  D. Sham Recycling Policy
  E. Submittal of Part B Applications
  F. DRE Testing
  G. Chlorinated Dioxins and Furans
  H. Special Requirements for Furnaces
  I, Special Metals Controls for Furnaces that Recycle Collected Paniculate Matter
  J. Recordkeeping
VIQ. Implementation of Today's Rule
  A. Newly Regulated Facilities
   1. Definition of "In Existence"
   2. Section 3010 Notification
   3. Part A Permit Application
  B. Interim Status Facilities
  C. Permitted facilities
   1. Amendment to 270.42(g)
   2. Procedures to Modify Permits
  D. Addition of Storage Units at Direct Transfer Facilities That Obtain Interim Status
   1. Unauthorized States
   2. Authorized States
  E. Compliance with BIF versus Incinerator Rules
DC. Permit Procedures
  A. Pan B Information
  B. Special Forms of Permits
   1. Permits for New Boilers and Industrial Furnaces

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     2. Permit Procedures for Interim Status Facilities
  X. Exemption of Small Quantity Burners
   A. Response to Comments                                               /
   B. Basis for Today's Rule
     1. Composition of Hazardous Waste Stream
     2. Toxicity of Hazardous Constituents
     3. Destruction Efficiency
     4. Assumptions Regarding Metals and Chlorine in Waste Fuels
   C How the Exemption is Implemented
     1. Use of Terrain-Adjusted Effective Stack Height
     2. Multiple Stacks
   D. Wastes Ineligible for Exemption
   E. Exemption of Associated Storage
   F. Notification and Recordkeeping Requirements
  XI. Exemption of Low Risk Waste from DRE Standard and Paniculate Matter Emissions
   Standard
   A. Exemption from Compliance with the DRE Standard
   B. Exemption from Compliance with the Paniculate Standard
   C. Eligibility Requirements
   D. How the Low-Risk Waste Exemption Works
     1. Constituents of Concern
     2. Estimation of Worst-Case Emissions
     3. Dispersion Modeling
     4. Acceptable Ambient Levels
     5. Constituents with Inadequate Health Effects Data
  XII. Storage Standards
   A. Permit Standards for Storage
   B. Consideration of Requirement for Liquid Waste Fuel Blending Tanks
   C. Standards for Direct Transfer Operations
     1. General Operating Requirements
     2. Inspections and Recordkeeping
     3. Equipment Integrity
     4. Containment and Detection of Releases
     5. Response to Leaks or Spills
     6. Design and Installation of New Equipment
     7. Closure
  XHI.  Applicability of the Bevill Exclusion to Combustion Residues When Burning
   Hazardous Waste
   A. Basis for Applying the Bevill Exclusion to Derived-From Residues
   B. Evolution of Interpretations
   C. Case-by-Case Determinations
     1. Eligible Devices
     2. Two-Part Test
   D. Recordkeeping
   E. Other Considerations
     1. Generic Determinations
     2. Burning for Destruction
PART FOUR: MISCELLANEOUS PROVISIONS
  I. Regulation of Carbon Regeneration Units
   A. Basis for Regulating Carbon Regenerating Units as Thermal Treatment Units
   B. Definition of Carbon Regeneration Unit and Revised Definition of Incinerator
   C. Units in Existence on die Effective Date are Eligible for Interim Status
  n. Regulation of Sludge Dryers
   A. July 1990 Proposal

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   B. Summary of Public Comments
  ITL Classification of Coke and By-Product Coal Tar
   A. AISI Petition
   B. Process Description
   C Basis for Approval of die AISI Petition
  IV. Regulation of Landfill Gas
  V. Definitions of Infrared and Plasma Arc Incinerators
PART FIVE: ADMINISTRATIVE, ECONOMIC, AND ENVIRONMENTAL IMPACTS,
  AND LIST OF SUBJECTS
  L State Authority
   A. Applicability of Rules in Authorized States
   BJEffect on State Authorizations
  EL Regulatory Impacts
   A. Cost Analysis
     1. Background
     2. Revised Cost Analysis
   B. Regulatory Flexibility Act
   C. Paperwork Reduction Act
  in. List of Subjects
Appendices

PART ONE:  BACKGROUND

I. Legal Authority

      These regulations are promulgated under authority of sections 1006,2002,3001
through 3007,3010, and 7004 of the Solid Waste Disposal Act of 1970, as amended by
die Resource Conservation and Recovery Act of 1976, the Quiet Communities Act of 1978,
die 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.

n. Overview  of the Final Rule

A. Controls for Emissions of Organic Compounds

      Today's rule requires boilers and industrial furnaces to comply with the same
destruction and removal efficiency (DRE) standard currently applicable to hazardous waste
incinerators:  99.9999% DRE for dioxin-Iisted waste, and 99.99% DRE for all other   .
hazardous wastes. In addition, the rule controls emissions of products of incomplete
combustion (PICs) by limiting flue gas concentrations of carbon monoxide (CO), and
where applicable, hydrocarbons (HQ to ensure that the device is operated under good
combustion conditions. Finally, emissions testing and health-risk assessment is required
for chlorinated dioxins and furans for facilities meeting specified criteria where the potential
            I
for significant concentrations may exist

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B. Controls for Emissions of Toxic Metals

       The rules establish emission limits for 10 toxic metals listed in Appendix VIE of 40
CFR Part 261 based on projected inhalation health risks to a hypothetical maximum
exposed individual (MEI). The standards for the carcinogenic metals (arsenic, beryllium,
eadmum, and chromium) limit the increased lifetime cancer risk to the MEI to a maximum
of 1 in 100,000. Hie risk from the four carcinogens must be summed to ensure that the
combined risk is no greater than 1 in 100,000.  The standards for the noncarcinogenic
metals (antimony, barium, lead, mercury, silver, and thallium) are based on Reference
Doses (RfDs) below which adverse health effects have not been observed.

       The standards are implemented through a three-tiered approach. Compliance with
any tier is acceptable. The tiers are structured to allow higher emission rates (and feed
rates) as the owner or operator elects to conduct more site-specific testing and analyses
(e.g., emissions testing, dispersion modeling). Thus, the feed rate limits under each of the
tiers are derived based on different levels of site-specific information related to facility
design and surrounding terrain. Under Tier I, the Agency has provided very conservative
waste feed rate limits in "reference" tables as a function of effective stack height and terrain
and land use in the vicinity of the stack and assumed reasonable, worst-case dispersion.
The owner or operator demonstrates compliance by waste analysis, not emissions testing or
dispersion modeling. Consequently, the Tier I feed rate limits are based on an assumed
reasonable, worst-case dispersion scenario, and an assumption that all metals fed to the
device are emitted (i.e., no partitioning to bottom ash or product, and no removal by an air
pollution control system (APCS)).

      Under Tier II, the owner or operator conducts emissions testing (but not dispersion
modeling)  to get credit  for partitioning to bottom ash or product, and APCS removal
efficiency.  Thus, the Agency has developed conservative emission rate limits in reference
tables, again as a function of effective stack height and terrain and land use in the vicinity of
die stack. The Agency also assumed reasonable, worst-case dispersion under Tier IL

      Under Tier ED, the owner or operator would conduct emissions testing and site-
specific dispersion modeling to demonstrate that the actual (measured) emissions do not
exceed acceptable levels considering actual (predicted) dispersion.

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       Hie standards are implemented through limits on specified operating parameters,
including hazardous waste feed rate and metals composition, feed rate of metals from all
feed streams, combustion chamber temperature, and APCS-specific parameters.

C. Controls for Emissions of Hydrogen Chloride and Chlorine Cos

       The roles control emissions of hydrogen chloride (HC1) and free chlorine (Cl2>
under liie same general approach as that used for metals. The owner and operator must
comply with and implement die HC1 and Ci2 controls in the same manner as for metals.

D. Emission Standard for Paniculate Matter

       The rules limit paniculate matter (PM) emissions to 0.08 gr/dscf, corrected to 7
percent oxygen (C>2). This is the same standard that currently applies to hazardous waste
incinerators and is intended  to supplement the risk-based  metals controls. (Metals
emissions are generally controlled by limiting feed rates of metals and controlling PM.)
Compliance with the standard is demonstrated by emissions testing, and  the standard is
implemented by operating limits in the permit on parameters including: ash content of feed
streams, feed rate of specific feed streams, and air pollution control system operating
parameters.  All boilers and industrial furnaces must comply with the standard; however,
cement and aggregate kilns need not monitor the ash feed rate of all feed streams to
demonstrate compliance with the standard given that paniculate matter from these devices is
generated primarily from raw materials.  Instead, the rule provides that these devices must
comply with the operating limits on the paniculate matter control system to ensure
continued operation at levels achieved during the compliance test (under interim status) or
trial burn (under die Part 6 permit application).

E. Permitting Procedures

       The final rule requires similar permitting procedures for regulated BIFs that apply to
hazardous waste incinerators. For example, owners and operators are required to submit a
Part B permit application for evaluation in order to be eligible for an operating permit
Permit applications will be called on a schedule considering the relative hazard to human
health and environment the facility poses compared to other storage, treatment, and
disposal facilities within the Director's purview.

F. Controls During Interim Status
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       Today's final role requires boilers and industrial furnaces that have interim status to
 comply with substantive emissions controls for metals, HC1, C12, particulates, and CO
 (and, where applicable, HC and dioxins and furans).  Owners and operators must certify
 compliance with the emissions controls under a prescribed schedule, establish limits on
 prescribed operating parameters, and operate within those limits throughout interim status.

 G. Units Exempt from Air Emissions Standards

       The role conditionally exempts from regulation the following devices: (!) boilers
 and industrial furnaces that burn small quantities of hazardous waste fuel (i.e., the small
 quantity burner exemption) and that operate the device under prescribed conditions; (2)
 smelting, melting, and refining furnaces that process hazardous waste solely for the
 purpose of metal reclamation and not partially for destruction or energy recovery; and (3)
 coke ovens if the only hazardous waste they process is  K087.

       The small quantity burner exemption -  as provided in section 3004(q)(2)(B) - is a
 risk-based exemption specifically alluded to in the statute. The exemption is provided only
 to hazardous waste fuels generated on-site, and is conditioned on a number of
 requirements, including a one-time notification and recordkeeping.
                    )                   ,
       The Agency is also providing a temporary exemption for metal reclamation furnaces
 from today's burner standards until we determine how best to apply rules designed for
combustion processes to noncombustion metal reclamation operations.  (It should be noted
that section 3004(q) requires EPA to issue rules controlling air emissions from devices
burning hazardous waste for energy recovery by a specified date. Section 3004(q) does
 not apply to devices burning hazardous waste for the sole purpose of material recovery.
Although EPA has authority to issue such regulations, the section 3004(q) deadline does
not apply.) To distinguish between wastes that are processed solely for metal reclamation
rather than (partial) destruction, the final rule considers  a hazardous waste processed by a
 smelting, melting, or refining furnace with a total concentration of Appendix Vffl, Part 261
toxic organic constituents exceeding 500 ppm to be burned at least partially for treatment or
destruction.  To distinguish between processing for material recovery and burning for
energy recovery, the final rule considers a hazardous waste processed by a metal
reclamation furnace with a heating value exceeding 5,000 Btu/lb to be burned at least
partially for energy recovery.  Metals reclamation furnaces claiming the exemption must

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notify the Agency, sample and analyze their hazardous wastes to document compliance
with the conditions of die exemption, and keep records of such documentation.

       Coke ovens are exempt from today's rule if the only hazardous waste they process
is K087 as an ingredient to produce coke. Given that K087 is for practical purposes just
like other materials used to produce coke and comes from the same process as these other
materials, it would be anomalous to assert RCRA control over the coking process.

H. Pollution Prevention Impacts

       This rule provides an incentive to reduce the generation of metal and chlorine-
bearing hazardous waste at the source given that the metals and HQ emissions controls will
be implemented by additional requirements attendant to the disposal of those wastes, i.e.,.
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 facility operator needs to bum.  Thus, the metals and HC1
controls 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 and HO mat would be implemented by feed rate
limits.

       Waste generators who send their waste to industrial furnaces such as cement kilns
and light-weight aggregate kilns that act as commercial waste management facilities will
have the incentive to reduce the generation of metal and chlorine-bearing wastes because
waste management fees are likely to increase for such waste given that the burner has a
fixed metal and chlorine feed rate allotment (due to prescribed feed rates and facility
operating conditions).  Wastes with extremely high metals content  may no longer be
acceptable for burning 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 bum their wastes on site also have the incentive to reduce
die generation of metal and chlorine-bearing wastes given that the rule will provide a fixed
feed rate allotment for their boiler or industrial furnace.
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HL  Relationship to Other Rules

A. Regulations to be Promulgated Under the New Clean Air Act

       Title m of the recent Qean Air Act Amendments of 1990, amending section 112 of
the Act dealing with hazardous air pollutants, potentially addresses many of the same
sources that would be regulated under today's rule. That section requires the Agency to
develop a list of major and area sources of hazardous air pollutants (a major source is a
stationary source that has the potential to emit up to 10 tons per year of a hazardous air
pollutant, or 25 tons per year of a combination of such pollutants, and area sources are
other stationary sources emitting hazardous air pollutants),  and to develop technology-
based controls for such sources over specified time periods.  See Clean Air Act, amended
sections 112(c), and (d).  Additional controls shall be imposed within eight years after
promulgation of each of these technology-based standards, if such controls are needed to
protect public health with an ample margin of safety, or to prevent adverse environmental
effect  (Cost, energy, and other relevant factors must be considered in  determining
whether regulation is appropriate in the case of environmental effects.) In addition, if the
technology-based standards for carcinogens do not reduce the lifetime excess cancer risk
for the  most exposed individual to less than one a million  (10-6), then EPA must
promulgate health-based standards. See amended section 112(f)(2)(A).

       It is premature for  the Agency to attempt  to provide a definitive opinion on the
relationship of these provisions to today's rule. Sources covered by the present rule may
not ultimately be required to be further regulated under amended section  112.  In this
regard,  amended section 112(n)(7) provides that  if sources' air emissions are regulated
under subtitle C, "the Administrator shall take  into  account  any regulations  of such
emissions ...  and shall , to the maximum extent practicable  and consistent with the
provisions of this section, ensure that the requirements of such subtitle and this section are
consistent"  Thus, at a minimum, Congress was concerned about the potential for
duplicative regulation and urged the Agency to guard against  it  Since the Agency regards
today's  rules as protective (based on present knowledge),  it may be possible to avoid
further air emissions regulation. (EPA notes, however, that these sources will likely be
listed as major sources, and the Agency will study whether further emissions controls are
required in the course of implementing amended section 112.)
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B. April 27,1990 Proposed Incinerator Amendments

       On April 27, 1990 (55 FR 17862), EPA proposed amendments to the existing
hazardous waste incinerator standards of Subpart O, Part 264 to make the incinerator
standards conform to the emissions standards being promulgated today for boilers and
industrial furnaces burning hazardous waste.  The proposed rule would  add emission
standards for products of incomplete combustion (i.e., carbon monoxide and hydrocarbon
limits), metals, and hydrogen chloride and chlorine gas.

       In the proposed rule for incinerators, EPA  also proposed to revise or to add
definitions for a number of thermal treatment devices:  industrial furnace, incinerator,
plasma arc and infrared incinerators. Those definitions are being promulgated in today's
rule. In addition, EPA proposed in the incinerator rulemaking to clarify the regulatory
status of carbon regeneration units and fluidized bed incinerators. Those clarifications are
also promulgated in today's final rule.

       Finally, EPA proposed to revise the definition of principal organic hazardous
constituents (POHCs) used to demonstrate destruction and removal efficiency (DRE). The
revised definition would allow the Director on a case-by-case basis to approve as POHCs
compounds that are neither constituents in the hazardous waste nor organic. That revised
definition of POHC is finalized in today's rule as a part of the DRE standard to control
organic emissions from boilers and industrial furnaces.

C.  July 28,1990 Proposed Amendment to Definition of Wastewater Treatment Unit to
    Exempt Sludge Dryers

       On July 28,1990 (see 55 FR 29280), EPA proposed to clarify the regulatory status
of sludge dryers to make it clear that sludge dryers that meet the definition of a tank and that
were a  part of a wastewater treatment unit were exempt from RCRA regulation even if they
heretofore met the definition of an incinerator. Today's final rule promulgates a definition
of sludge dryer and revises the definition of incinerator to explicitly exclude  sludge dryers.
See Part Four,  section n of today's preamble.

D. Land Disposal Restriction Standards

       In the May 6, 1987 proposal,  the Agency indicated that once the present rules
became final, the Agency would amend certain of the land disposal restriction standards
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that specified incineration as a treatment standard (at that time, the standard for HOCs under
the California list rule), to also include burning in boilers and industrial furnaces.  See 52
FR at 17021.  Since that time, the issue has become more involved.  In particular,
significant issues regarding the relationship of the Bevill amendment and land disposal
restrictions exist (which the Agency in fact referenced in the rulemaking record to the
California list rule when considering this issue). The Agency believes it inappropriate to
iry and resolve these issues in this proceeding, given the tiny,  onstraints created by the
District Court's order and the fact that this rulemaking does not deal principally with issues
relating to the land disposal restrictions program.  The Agency consequently plans to
address these questions in a later proceeding and not to finalize the May 1987 proposal at
this time.

PART TWO:  DEVICES SUBJECT TO REGULATION

I.  Boilers

       EPA defines a boiler in 260.10 as an enclosed device using controlled flame
combustion and having  the following characteristics:  (1) the combustion chamber and
primary energy recovery section must be of integral design; (2) thermal recovery efficiency
must be at least 60 percent; and (3) at least 75 percent of the recovered energy must be
"exported" (i.e., not used for internal uses such as preheating of combustion air or fuel, or
driving combustion air fans or feed water pumps).

      Today's final rule applies to all boilers burning hazardous waste for any purpose --
energy recovery or destruction. (We note, however, that an existing boiler may not bum
hazardous waste for destruction (i.e., waste that is not a fuel) before certifying compliance
with the interim status emissions standards.)                   x

      Nonindustrial boilers are currently prohibited from burning hazardous waste unless
they are operated in confonnance with the incinerator standards of Subpart O of Parts 264
or 265.  On the effective date of today's rule, however, nonindustrial boilers burning
hazardous waste will be  subject to these boiler and industrial furnace rules. We note that
nonindustrial boilers generally cannot bum hazardous waste until they receive an operating
permit under today's rule  (unless they are already  operating  under the incinerator
standards). This is because the prohibition is not rescinded until the effective date of the
rule, and a facility would have to be "in existence" with respect to hazardous waste burning
on that date to be eligible for interim status.
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       EPA believes that approximately 925  boilers burn hazardous waste fuels.
Approximately 600 of these boilers bum very small quantities of hazardous waste and will
be conditionally exempt under the small quantity burner provision of today's rule. See
266.109. (We note that these boilers burn less than one percent of the total hazardous
waste currently being burned in boilers and industrial furnaces.) EPA also believes that
approximately 200 boilers, will stop burning hazardous waste because they bum quantities
exceeding the small quantity burner exemption but do not burn enough waste to justify the
cost of complying with today's rule.  Thus,  approximately 125 boilers will continue to
burn hazardous waste  and will be subject to the interim status and permit standards
provided by 266.102 and 266.103 of today's rule.

II.   Industrial Furnaces

       Under today's revised definition, EPA defines an industrial furnace in 260.10 as
those designated devices that are an integral component of a manufacturing process and that
use thermal treatment to recover materials or energy. With the addition of halogen acid
furnaces by today's rule, the Agency has  designated 12 devices as industrial furnaces:
cement kilns;  lime kilns; aggregate kilns (including light-weight aggregate kilns and
aggregate drying kilns used in the asphaltic concrete industry); phosphate kilns; coke
ovens; blast furnaces; smelting, melting, and refining furnaces; titanium dioxide chloride
process oxidation reactors; methane reforming furnaces; pulping liquor recovery furnaces;
and combustion devices used in the recovery of sulfur values from spent sulfuric acid. The
definition also includes criteria and procedures for designating additional devices as
industrial furnaces.

       Any industrial furnace burning or processing any hazardous waste for any purpose
- energy recovery, material recovery, or  destruction - is subject to today's rule, with
certain exceptions. Furnaces (like boilers) burning small quantities of hazardous waste fuel
are exempt from regulation under 266.108, coke ovens are exempt from regulation if the
only hazardous waste they bum is Hazardous Waste No. K087, and regulation of smelters
processing hazardous waste solely for material recovery is deferred (see discussion in
section
       The Agency believes that approximately 75 industrial furnaces burn over one
million tons of hazardous waste annually.  The regulated universe appears to comprise
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approximately 40 cement kilns, 18 light-weight aggregate kilns, and  15 halogen acid
furnaces. Each of these types of furnaces is described below.

A. Cement Kilns

       Cement kilns are horizontal inclined rotating cylinders, refractory lined and
internally fired, to calcine a blend of 80% limestone and 20% shale to produce Portland
cement  There is a wet process and a dry process for producing cement.  In the wet
process, the limestone and shale are ground wet and fed into the kiln in a slum1.  In the dry
process, raw materials are ground dry. Wet process kilns are longer than dry process kilns
in order to facilitate water evaporation from the wet raw material. Wet kilns can be more
than 450 feet in length. Dry kilns are more thermally efficient and frequently use preheaters
or precalciners to begin the calcining process before the raw material is fed into the kiln.

       Combustion gases and raw materials move counterflow in kilns.  The kiln is
inclined, and raw materials are fed into the upper end while fuels are normally fed into the
lower end.  Combustion gases thus move up the kiln counter to the flow of raw materials.
The raw materials get progressively hotter as they travel the length of the kiln.  The raw
materials eventually begin to soften and fuse at temperatures between 2,250 and 2,700F to
form the clinker product. Clinker is then cooled, ground, and mixed with other materials
such as gypsum to form Portland cement

       Combustion gases leaving the kiln typically contain from 6 to 30% of the feed
solids as dust  Paniculate emissions are typically controlled with electrostatic precipitators
or fabric filters (baghouses), and are often recycled to the kiln feed system.

       Dry kilns with a preheater or precalciner often use a by-pass duct to remove from 5
to 30% of the kiln off-gases from the main duct. The by-pass gas is passed through a
separate air pollution control system to remove paniculate matter.  By-pass dust  is not
reintroduced into the kiln system to avoid a build-up of metal salts that can affect product
quality.

       Some cement kilns bum hazardous waste fuels to replace from 25 to 75% of normal
fossil fuels. Most kilns burn liquid waste fuels but several burn small (e.g., six gallon)
containers of viscous or solid hazardous waste fuels. Containers have been fired into the
upper, raw material end of the kiln and at the midpoint of the kiln.
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       Several cement companies have also expressed an interest in using solid hazardous
waste SBch as contaminated soils as an ingredient to produce cement. Cement kilns that
bum hazardous waste as an ingredient are regulated by today's rule.1 Under today's rule,
a facility may burn (or process) hazardous waste solely as a bona fide ingredient during
interim status beginning with the effective date of the rule.  If a waste is burned partially for
desxnctxm or energy recovery, however, it is not burned solely as an ingredient and
special restrictions apply during interim status (see discussion below). EPA considers a
waste CD be burned atkast partially for destruction if it contains a total of 500 ppm or more
by weight of nonmetal hazardous constituents listed in Appendix Vffl, Pan 261.  Further,
EPA considers a waste to be burned at least partially for energy recovery if it has a heating
value of 5,000 Btu/lb or more.

       Today's rule does not allow burning of a waste for the purpose of destruction
during interim status prior to certification of compliance (see 266.103(c))  with all
applicable emission standards. Further, the rule applies special requirements during interim
status on owners/operators who feed hazardous waste into a kiln system at any  location
other than the "hot" end  where product is discharged.   Hazardous waste burned
(processed) solely as an ingredient, however, is not subject to the special requirements
because emissions from such burning would not pose an adverse effect on human health
and the environment2

B. Light-Weight Aggregate Kilns

       Light-weight aggregate (LWA) describes a special use aggregate with a specific
gravity much less  than  sand and gravel which is used to produce insulation and
nonstructural and light-weight concrete. LWA is produced  much like  cement, but the
feedstocks are special clays, pumice, scoria, shale, or slate.

       The LWA kiln is configured much like a cement kiln. The raw material is crushed
and introduced at the upper end of a rotary kiln. In passing through the kiln, the materials
reach temperatures of 1,900 to 2,100F. Heat is provided by a burner at the lower end of
the kiln where clinker is discharged
1      See discussion in section VH.H of Pan Three of the text
2      This is because nonmetal toxic constituents will not be present in the waste at
significant levels (Le., less man 500 ppm) and metal emissions will be adequately
controlled under today's rule by the air pollution control system irrespective of where the
waste is fed into the kiln system.

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       LWA kilns are also major sources of paniculate emissions and are equipped with
wet scrubbers, fabric filters, or electrostatic prccipitators.  Wet scrubbers dominated the
industry until recently. Many facilities are now converting to dry systems to reduce the
cost of residue management by recycling the collected dust into the kiln.

       LWA kilns that burn hazardous waste fuel typically burn 100% liquid hazardous
waste fuels.

C. Halogen Acid Furnaces

       The Dow Chemical Company (DOW) filed a rulemaking petition with EPA on
March 31, 1986, in accordance with the provisions of 40 CFR 260.20, requesting that
EPA designate their halogen acid furnaces (HAFs) as industrial furnaces.  HAFs are
typically modified firetube boilers that process secondary waste streams containing 20 to 70
percent chlorine or bromine to produce a halogen acid product by scrubbing acid from the
combustion gases. Currently HAFs that produce steam meet the definition of a boiler while
HAFs that do not generate steam meet the definition of an incinerator even though they use
hazardous waste as a fuel and as an ingredient to produce halogen acid product Today's
rule designates HAFs that do not  generate steam as an industrial furnace for the reasons
given below.

       DOW petitioned the Agency to designate their HAFs as industrial furnaces after the
Agency changed the definition of incinerator in  1985 from a "purpose of burning test" to a
"design test" and developed new classifications for boilers and industrial furnaces. The
Agency inadvertently did not designate HAFs as industrial furnaces at that time which
potentially left certain HAFs operating not in compliance with the incinerator standards
promulgated in 1981. Although HAFs (prior to today's rule) technically meet the definition
of incinerator, the Agency has indicated its intention since receiving the DOW petition to
correct the problem and to properly designate HAFs as industrial furnaces.

       On May 6,1987 (52 FR 17033), EPA proposed to grant this petition and to add
halogen acid furnaces (HAFs) to the list of devices that are designated as industrial furnaces
under 40 CFR 260.10. On April 27,1990 (55 FR 17917), the Agency proposed changes
to the proposed designation of HAFs as industrial furnaces. With modifications based on
additional information and comments, today's rule adds HAFs to the list of devices that are
included in the definition of an industrial furnace under 260.10.
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       IB ndx^Kmlc, EPA is defining an "industrial furnace" in 260.10 as an enclosed
device feat uses ihennal treatment to recover (or produce) materials or energy as an integral
component of a manufacturing process.3 EPA has previously designated 11 devices as
industrial furnaces: (1) cement kilns; (2) lime kilns; (3) aggregate kilns (including light-
weight aggregate kilns and aggregate drying kilns used in the asphaltic concrete industry);
(4)pbospteBck!las; (5) coke ovens; (6) blast furnaces; (7) smelting, melting, and refining
furnaces; (8) titanmm dioxide chloride process oxidation reactors; (9) methane reforming
furnaces; (10) pulping liquor recovery furnaces; and (11) combustion devices used to
recover suirar values from spent sulfuric acid.

       The industrial furnace definition in 260.10 also provides criteria and procedures for
adding devices to the list  A device may be defined as an industrial furnace if it meets one
or more of the following criteria: (1) the device is designed and used primarily to recover
material products; (2) the device is used to bum or reduce raw materials to make material
products; (3) the device is used to burn or reduce secondary materials as  effective
substitutes for raw materials in processes that use raw materials as principal feedstocks; or
(4) the device is used to bum or reduce secondary materials as ingredients in industrial
processes to manufacture material products.

       As explained  below, the basis for designating HAFs as industrial furnaces under
260.10 is that HAFs are integral components of a manufacturing process, they recover
materials and energy, and they meet two of the criteria (1 and 4) described above for
classifying a device as an industrial furnace.

       1. Current Practices. Information available to EPA indicates that at least 3
companies in the United States operate at least 30 devices that may be halogen acid
furnaces. These devices typically process chlorinated or brominated secondary materials
with 20 to 70 percent halogen content  (by weight) to produce an acid product, either
hydrogen chloride (HC1) or hydrogen bromide (HBr), both of which  have a halogen
content that ranges from 3 to greater than 25 percent (by weight).  These secondary
3      This definition of industrial furnace is the revised definition as noticed on April 27,
1990 (55 FR 17869).  The previous definition read "an enclosed device using controlled
flame combustion to recover materials or energy as an integral component of a
manufacturing process." Public comments on the proposal are discussed in the Comment
Response Document for the RTF Regulations. EPA revised the definition to include
nonflame devices (Le., by referring to thermal treatment) because controlled-flame devices
and nonflame devices can have the same emissions and pose the same hazard to human
health and the environment
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 materials typically have as-fired heating values of approximately 9,000 Btu/lb and are
 typically produced on site.

       Some of the HAFs currently in use are modified firetube boilers that generate and
 export steam. These HAFs meet the definition of a boiler under 260.10, and, thus, will be
 regulated as boilers. The remaining HAFs, although modified firetube boilers, do not
 generate steam and thus do not meet EPA's definition of a boiler. Today's rule classifies
 these nonboiler HAFs as industrial furnaces. For the remainder of this discussion, the term
 "HAF" refers to these nonboiler HAFs.

       2. Designation of HAFs as Industrial Furnaces.

       a. Dow's Petition. On March 31,1986, the Dow Chemical Company (DOW) filed
 a rulemaking petition with  EPA in accordance with the provisions of 40 CFR 260.20,
 requesting that HAFs at Dow  Chemical be designated as industrial furnaces.  EPA
 proposed to grant this petition in the May 6,1987 proposal. Today's rule includes HAFs
 in the definition of an industrial furnace under 260.10.  Further background discussion on
 DOW's petition is contained in the May 6,1987 proposed rule.

       b. May 1987 and April 1990 Proposed Rules. EPA proposed to designate HAFs
 as industrial furnaces for the reasons discussed in the May 6, 1987 proposed rule.  To
 ensure that a particular device was an industrial furnace involved in bona fide production of
 acid4 as  an  integral component of a manufacturing process, and was not an incinerator
 equipped with halogen emissions removal devices, the 1987 proposed HAF definition
 required that: (1) the furnace be located on site at a chemical production facility; (2) the
 waste fed to the device be halogenated; and (3) the acid product from the device contain at
 least 6 percent halogen acid

       Based on comments received on the 1987 proposal and on further consideration by
 the Agency, EPA proposed revisions to the HAF definition in the April 1990 notice. These
revisions were proposed for two reasons: (1) to better clarify  the differences between
4      The Agency's concern is that devices capturing some HO in scrubber effluent not
automatically be classified as HAFs if they find a way to utilize the scrubber effluent The
HC1 content of the effluent from wet scrubbers used to control HO emissions from the
incineration of chlorine-bearing waste is normally on the order of 1 percent or less. EPA
does not consider such low HQ content scrubber water a bona fids product for purposes of
designation as an industrial furnace even if the scrubber water is beneficially used in a
manner that specifically relates to its HC1 content

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HAFs and incinerators equipped with wet scrubbers to control halogen acid emissions, and
(2) to tetter reflect industry practice.

      To ensure that  a particular device is an integral component of a chemical
manufacturing process, the April 1990 proposal included requirements that at least 50
percent of the acid product be used on site and that any off-site waste fed to the HAF be
genciaied by a SIC2S) (inorganic chemicals) or SIC 286 (organic chemicals) process. To
ensure mat the waste is burned as a bona fide ingredient to produce the halogen acid
product, the April 1990 proposal also required thai each waste fed to the HAF have an "as-
generated" halogen content of at least 20  percent  In addition, to better reflect industry
practice, the 1990 proposal required that the acid product have a halogen acid content of 3
percent rather than 6 percent, an amount that  still clearly  distinguished the HAF acid
product from incinerator scrubber water, which  has  an acid content of well below 1
percent.  Finally, EPA proposed in April  1990 to list  hazardous waste fed to a HAF as
inherently waste-like to ensure that halogenated waste fed to a HAF (and the HAF itself)
would be subject to regulation. This would preclude a claim that the secondary materials
were used as ingredients to make a product,  and, thus, not a solid waste under
       c. Summary of Public Comments.  Commenters on the 1987 and 1990 proposed
rules objected to the requirements that 50 percent of the acid product be used on site and
that any off-site waste feed be limited to SIC 281 or 286 processes.  The commenters
argued that minimum specifications on the halogen content of the feed and/or the acid
content of the HAF product are sufficient to distinguish bona fide HAF operations from
incinerator operations, and that the requirement that a substantial portion of the product be
used on site serves only to limit the legitimate treatment of halogenated wastes and the sale
of bjmafidfc HAF products without being necessary to  protect human health and the
environment

       After consideration of these commenters' concerns, the Agency believes that both
the proposed off-site restriction for waste fed to HAFs  and  the proposed on-site acid
product use restriction are indeed unnecessary to ensure that HAFs are integral components
of manufacturing processes. The Agency agrees with the commenters that the requirements
specifying the minimum halogen content of the waste feed and  the minimum halogen acid
concentration  of  the HAF product are sufficient to ensure that  HAFs are integral
components of a manufacturing process (i.e., the process of halogen acid production).
EPA is not adopting these proposed conditions given that air emissions from HAFs will be

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 regulated under today's rale, that these proposed conditions were directed at how to
 classify these devices rather than how to ensure their safe operation, and that HAF
 operations (as properly controlled) are environmentally advantageous in that they utilize
 acid values rather than dispose them and therefore should not needlessly be discouraged.
 Today's rule, therefore, does not restrict the use of HAF waste feeds generated off site or
 require that any percentage of the acid product be used on site.

        In today's rule, the Agency considers a bjf.a. fjj HAF operation as one in which a
 secondary material with a minimum as-generated halogen content of 20 percent by weight
 is processed into an acid product with a minimum halogen content of 3 percent by weight.
 The acid product must be used in a manufacturing process either on site or off site. The
 Agency maintains that this approach will allow  the legitimate processing of highly
 halogenated secondary materials into usable products but will still clearly distinguish HAF
 product acid from incinerator halogen acid scrubber water.

        Upon review of other comments submitted on the 1987 and 1990 proposed rules,
 the Agency has identified several issues pertaining to HAFs that require clarification in the
 regulations. Specifically, these issues concern: (1) the regulation of chlorine emissions
 from HAFs, (2) the operation of HAFs under the special operating requirements (SOR)
 exemption for boilers, and (3) the designation of hazardous  waste fed to HAFs as
 inherently waste-like material.

        One commenter to the  1987  proposed rule requested that the Agency clarify its
 position on limiting inorganic halide salts in feedstocks to boilers and industrial furnaces.
 The Agency has established limits on emissions of Hd and Cl2 from industrial furnaces,
 and a HAF operator, like any other industrial furnace operator, must comply with these
 HC1 and Cl2 emission standards.  To demonstrate compliance under the Tier 1 feed rate
 screening limits, a HAF operator must include  inorganic chlorine as pan  of the total
 chlorine fed to the device.  The Agency believes that this requirement is justified because
 recent testing indicates that even thermally stable compounds such as NaCl are convened
 with high efficiency to HQ under laboratory conditions that simulate incineration.5

        Another commenter to the 1987 proposal stated that HAFs are unjustly excluded
 from the automatic waiver of a trial burn to demonstrate 99.99% destruction and removal
 efficiency (DRE) when operated under the special operating requirements (SORs). The
5     u.S. EPA, Lafrflratflry Method to Estimate Hydrogen Chloride Emfosjjon
Before Incineration of  Waste. February 1990.
                                       21

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           >.
Agency acknowledges the coramentcr's concern, but notes that all industrial furnaces,
including HAFs, are ineligible for the automatic DRE trial bum waiver. The Agency stated
in the preamble to the 1987 proposal that modified boilers that produce and export steam
(and thus meet EPA's definition of boiler in 260.10) would be regulated as boilers. In
such a case, the unit may be eligible for the automatic waiver of the DRE trial burn, which
applies only to boilers.  Any halogen acid furnace that is a modified fire-rube boiler not
meeting the definition  of a boiler in 260.10, however, would not be eligible for the
automatic waiver. Hie Agency's reasons for applying the automatic DRE trial burn waiver
only to boilers are discussed further in Section II.C.2.d of this preamble.

       Several commenters expressed concern that the April 27,1990 proposal required a
minimum heating value of 5,000 Btu/lb for secondary materials fed to HAFs. Today's
final rule does not require a minimum heating value on secondary materials fed to HAFs.
Although the Agency understands that most wastes burned in HAFs have a heating value
greater than 5,000 Btu/lb and, so, the HAFs are engaged in energy recovery as well as
materials recovery, not all wastes meeting the minimum halogen limit also have a heating
value normally associated with energy recovery.  The Agency believes that HAFs need not
be required to recover both material and energy values from every hazardous waste fed to
the device to meet the definition of an industrial furnace, and that the regulations adopted
today for HAFs ensure that they  will be operated in a protective manner even if energy
values are not recovered.

       Commenters' misconceptions regarding  a minimum heating value for secondary
materials may have arisen from  the Agency's proposal pursuant to 261.2(d)(2) to list
hazardous waste fed to HAFs as inherently waste-like material.  In today's rule, the
Agency is listing as inherently waste-like any  secondary material fed to HAFs that is
identified or listed as a hazardous waste under 40 CFR Part 261, Subparts C  and D.
Without such materials being designated as inherently waste-like, HAFs burning hazardous
wastes solely as ingredients (i.e., wastes that have low heating value and therefore, are not
burned partially for energy recovery) to produce an acid product might not be regulated
because the material  they are burning might not be  a solid waste  pursuant  to
261.2(e)(l)(i). However, HAFs that bum  hazardous wastes with high heating values
(i.e., greater than 5,000 Btu/lb), would be subject to today's rule even without listing them
as inherently waste-like because these wastes are considered under 261.2(e)(2)(ii) to be
burned at least partially for energy recovery. For reasons discussed in the April 27,1990
proposed rule (55 FR 17892). the Agency believes that such an inconsistent result would
                                       22

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 not provide adequate protection of human health and the environment (the wastes burned
 by HAFs are some of the roost toxic generated and regulation of emissions from burning
 these wastes certainly is needed to protect human health and the environment). Moreover,
 there are significant elements of treatment associated with burning in HAFs: toxic organic
 compounds are destroyed rather than recovered, and the burning if conducted improperly
 could become pan of the waste disposal problem. Because the materials burned in HAFs
 meet the criteria of 261J2(d) for inherently waste-like materials, EPA today is adding to
 the list of inherently waste-like materials under 261.2(d)(2) secondary materials fed to
 HAFs that are listed or identified as hazardous waste under Subparts C or D of Pan 261.
 While HAFs will not be precluded from burning secondary materials with low heating
 values, today's listing will prevent the HAFs that burn this material and the material itself
 from being unregulated. As a result,  in all cases, hazardous waste fed to HAFs, and the
 HAFs themselves, will be subject to hazardous waste regulations under today's final rule.
           i
       d.  Basis for Designating HAFs as Industrial Furnaces.  EPA has defined an
 industrial furnace in 260.10 as any of the specifically-designated enclosed devices that are
 integral components of a  manufacturing process and that use  thermal treatment to
 accomplish recovery of materials or energy. To date, 11 types of devices have been
 designated as industrial furnaces. The industrial furnace definition also provides criteria for
 adding devices to the list. As discussed above, these criteria include: (1) the design and
 use of the device primarily to accomplish recovery of material products; (2) the use of the
 device to bum or reduce raw materials to make a material product; (3) the use of the device
 to burn or reduce secondary materials as effective substitutes for raw materials in processes
 using raw materials as principal feedstocks; and (4) the use of the device to bum or reduce
 secondary materials as ingredients in an industrial process to make a material product.  As
 explained below, HAFs meet the definition of an industrial furnace as well as two of the
 above criteria, (1) and (4), for designating additional devices as industrial furnaces.

       HAFs are Integral Components of a Manufacturing Process. HAFs are commonly
 located on-site at large scale chemical manufacturing processes that reclaim primarily
 secondary materials generated on-site and that typically use the halogen acid product on-
 site. In these cases, die Agency believes the device should clearly be considered an integral
component of the manufacturing process and, thus, eligible for designation as an industrial
furnace. The situation is less clear when the device receives halogen-bearing secondary
materials from off-site or if the halogen acid product is sent off-site. In these situations, the
Agency believes, nonetheless, that the device should be considered an integral component
                                       23

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of amanofectanng process and, thus, eligible for consideration as an industrial furnace
provided that the device is located on the site of a manufacturing process and that the
halogen acid product is used by a manufacturing process.

      HAFs Recover Materials and Energy. EPA believes that HAFs recover materials
and energy to produce a bona fide product Production of halogen acid (a 3 to 20 percent
halogen add solution) from the combustion of chlorine-bearing secondary materials
con&iiitties materials recovery in the context of the designation of HAFs as industrial
furnaces.  HAFs can also be considered to burn secondary materials as ingredients in an
industrial process to make a material product (i.e., the product halogen acid). As discussed
above, chlorine-bearing secondary materials are burned to produce the halogen acid product
for use in a manufacturing operation.

      HAFs also recover energy. Most halogen-bearing secondary materials reclaimed in
HAFs are burned partially for energy recovery because substantial, usable h'eat energy is
released by the materials during combustion. The materials typically have  an as-fired
heating value of approximately 9,000 Btu/lb, and the heat released results in the thermal
degradation of chlorinated organic compounds to form Hd Although under definitions in
260.10, energy recovery in a boiler is characterized by the recovery and export of energy,
energy recovery in an industrial furnace need not involve any export of energy. Rather,
energy recovery in an industrial furnace is based on the burning of materials with
substantial heating values (greater than 5,000 Btu/lb) in a manner that results in the release
of substantial usable heat energy. See 50 FR 49171-49174 (November 29,1985).6

      HAFs Meet Industrial Furnace Criteria. The Agency believes that HAFs meet two
of the above criteria (i.e., criteria (1) and (4)) for designating devices as industrial furnaces.
EPA believes that restrictions on the halogen content of waste streams fed to HAFs and on
the halogen content of the acid product ensure that the HAF is: (a) designed primarily to
recover halogen acid (and so is not engaged in incineration); and (b) used to burn
secondary materials as ingredients in the process of halogen acid production to produce a
material product (i.e., the product halogen acid).

      Addition of HAFs to List of Industrial Furnaces.  EPA believes that HAFs are
integral components of a manufacturing process and that they are designed and operated to
 6 .    We note as discussed previously in the text that, although all hazardous wastes fed
 to a HAF must have an as-generated halogen content of at least 20%, all such wastes need
 not have a heating value of 5,000 Btu/lb.
                                       24

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recover materials and energy. For these reasons EPA is today adding to the list of devices
designated as industrial furnaces under 260.10 HAFs defined as furnaces that: (1) are
located at die site of a manufacturing process; and (2) process hazardous wastes with a
minimum as-generated halogen content of 20 percent by weight to produce an acid product
with a minimum halogen content of 3 percent by weight and where the acid product is used
in a manufacturing process.

       e. Interim Status for HAFs. HAFs that are in existence on the effective date of
today's rule are eligible for interim status like other boilers and industrial furnaces burning
for energy or material recovery. Although certain HAFs may technically have met the
amended definition of incinerator, EPA believes that there was legitimate confusion as to
such units' operating status.  These devices would not have been incinerators under the
original 1980 definition of incinerator because their primary purpose was not destruction of
waste. When EPA amended that definition in 1985 to adopt a definition based on the unit's
design rather than its operating purpose, the Agency did not intend to regulate HAFs as
incinerators and noted that the regulatory change was not intended to (or expected to) affect
the number and identity of regulated incinerator units. See 50 FR 625 (Jan. 4, 1985).
Moreover, given that many HAFs met the definition of boiler, it would have  been
anomalous and unintended for some HAFs to be subject to full regulation and others to be
unregulated (until the present rules were adopted). Given these circumstances, the Agency
is finding pursuant to 270.10(e)(2) that there was substantial confusion as to which HAF
owners and operators were required to submit a Pan A application and that this confusion
is attributable to ambiguities in the subtitle C rules.  Accordingly, such owners and
operators may submit Part A applications by the effective date of today's regulation.

       We note that this policy  on interim status eligibility date does not apply to other
devices that are currently subject  to regulation as an incinerator but claim to be an industrial
furnace subject to the BIF rule and its interim status eligibility date. An example is an
aggregate kiln that currently burns hazardous waste for the purpose of treatment
(destruction) and, so, is subject  to the incinerator standards of Subpart O, Parts 264 and
265.  There is no ambiguity  about the regulatory status of such a device given that the
Agency clearly intended for such burning to be subject to the incinerator standards, and the
Agency's rules have always so stated.  Thus, the date for interim status eligibility for such
facilities is the  1981 date for incinerator interim status.
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D.  Smelting, Melting, ami Refining Furnaces Burning Hazardous Waste to Recover
     Moots

       In the October 1989 supplement .to the proposed rule, EPA solicited  further
comment on an appropriate regulatory regime for smelting furnaces burning hazardous
waste for the exdashw purpose of material recovery. See 54 FR 43733.  This issue was
closely connected with the question of jurisdicrional limitations on the Agency's authority
to regulate industrial furnaces burakg secondary materials for material recovery, discussed
under the rubric of indigenous wastes. Id. at 43731-32.  The Agency noted generally that
where it did not perceive jurisdiction^ limitations on its authority, it regarded regulation of
organic emissions from smelting furnaces as unnecessary given the normal absence of
organics in the material feed to the unit. We also indicated concern at the prospect of
regulating emissions of metals that were not attributable to the processing of hazardous
waste, and accordingly solicited comment as to a means of determining when burning of
hazardous waste resulted in emissions in excess of those from processing other materials in
the device.  Id.,  at 43733.  With respect to a test for determining when wastes are
indigenous, the Agency reproposed a fairly broad test that would have had the effect of
excluding many wastes and devices from the Agency's jurisdiction, but would have
distinguished between wastes being burned for the purpose of conventional treatment, and
for the purpose of material recovery treatment

       These proposals proved extremely controversial.  Perhaps more importantly, after
the proposal was issued, the question of indigenous waste was the partial subject of the
District of Columbia Circuit Court of Appeals' decision API v. EPA. 906 F. 2d 726 (D.C.
Cir, 1990).  In that decision, the court stated that the Agency had been overly restrictive in
interpreting the jurisdictional limitations imposed by the statutory definition of solid waste
based upon the court's earlier opinion in American Mining Qpnpess v. EPA. 824 F. 2d
1177 (D.C. Cir. 1987).  That  earlier opinion, the  court held, is limited to situations
involving continuous recycling processes that are not part of the waste disposal problem,
and certainly does not mandate the type of indigenous principle mat the Agency discussed
in the 1989 notice. 906 F.2d at 740-41. The court accordingly remanded and directed the
Agency to rethink whether any type of indigenous principle is warranted given the court's
clarification of its earlier opinion.7 Ii at 741.
7      Technically, the court remanded the Agency's decision not to formally adopt a
treatment standard under the land disposal restrictions program for the residue from
processing a waste die Agency had indicated would be indigenous to a particular type of

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       The court's opinion, as wen as the many comments on this issue, raise complex
issues that EPA has not yet resolved  (In this regard, the Agency notes that the mandate in
section 3004(q) to regulate facilities burning hazardous waste for energy recovery as may
be necessary to protect human health and the environment does not apply to devices
burning for the purpose of material recovery, H. Rep. No. 198, 98th cong. 1st Sess. 40,
and so the court-ordered December 31, 1990 issuance date does not apply.) In particular,
the Agency is presently studying the question of jurisdiction as part of a comprehensive
effort to determine if the Agency's rules on recycling should be amended (either as a
regulatory matter or as pan of RCRA reauthorization).  In the interim, however, the
Agency does not believe it prudent to apply regulations to a whole potential class of devices
and wastes that the Agency has not fully evaluated (since these situations would have been
excluded from regulation under the proposal). See provision for conditional deferral of
smelting, melting, and refining furnaces under 266.100(c). In addition, because EPA has
placed most of its efforts into issuing the mandated portion of these regulations as soon as
possible, the Agency has not resolved the questions of how to regulate raised in the 1989
notice even for the class of smelting furnaces where authority would have existed under the
proposed view of indigenous waste.  The issue of whether material recovery is a form of   N
"treatment" is also presently submitted for decision to a panel of the D.C. Circuit in Shell
Oil v. EPA (No. 80-1532), and the Agency believes it prudent to await the Court's ruling.

       Another reason for deferring regulation of these devices is that the Agency wishes
to study further whether regulation under the Clean Air Act may be more appropriate than
RCRA regulation. Smelting, melting, and refining furnaces have been traditional subjects
of Clean Air Act regulation, and with the advent of amended section 112 of the Clean Air
Act amendments of 1990, technology-based controls on toxic air emissions are likely to
apply to these devices. Given that in many instances the principal risks potentially posed
by air emissions from these devices would come from the nonhazardous waste portion of
feed (see 54 FR at 43733), and that Clean Air Act regulation may result in control of
individual toxics, the Agency believes that further study of the most appropriate means of
regulation is warranted. (The Agency specifically requests information on other devices
that may burn hazardous waste solely for metal recovery. EPA will use such information
metal recovery furnace. Id* at 740. EPA has since indicated, in motions filed with the
Court, that it views the interim treatment standard based on stabilization as applying in all
cases where the residue remains a hazardous waste.
                                      27

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to consider whether the deferral for smelting, melting, and refining furnaces should be
broadened provided that the principles stated here apply to the other devices as well.)

       At the same time, EPA is concerned that this deferral not become a license for sham
recycling activities, or for operations motivated by conventional treatment objectives rather
than recovery purposes.  Accordingly, the Agency has crafted this deferral narrowly.
First, only smelting, melting, and refining furnaces  (as used in the 260.10 definition of
"industrial furnace") burning hazardous waste solely to recover metals would be eligible for
this deferral. In the unlikely event that one of these devices would be used to recover
organics or nonmetal inorganics, EPA believes that substantial amounts of organics would
be destroyed showing that the purpose of the activity was either conventional treatment or
energy recovery. (The Agency notes specifically that it intends to include as a smelting,
melting, or recovery furnace the types of high temperature metal recovery devices used as
the basis for the land disposal prohibition treatment standard for waste KO61, and other
similar devices.)

       Second, sham recovery operations would be viewed as conventional treatment
operations and would require a permit to control emissions.  Although it is difficult to
quantify when operations are sham, two fundamental notions are that any waste involved
must contain economically viable amounts of metals  to recover (the best objective measure
would be the same or greater levels of metal as in normal nonhazardous feed stocks), and
that the person recovering the metal be in the business of producing metals for public sale
(whether to an ultimate user or for further processing or manufacture). See also 53 FR at
522  (Jan. 8,1988).  The limitations on Btu level and levels on toxic organics discussed
below are further efforts to ensure that only fcpna fide metal recovery activities be deferred
from emissions regulation at this time.

       Third, today's regulations are  deferred only when these devices  bum (process)
hazardous waste exclusively for metal recovery and  not partially for destruction or energy
recovery as well. To implement this policy, today's rule provides that a waste with a
heating value of 5,000 Btu/lb or more (either as-generated or as-fired) is burned (at least
partially) as a fuel. The heating value limit is based on the Agency's long standing sham
recycling policy (48 FR 11157 (March 16,1983)) that wastes with a heating value of 5,000
Btu/lb or more are considered to be fuels. See also 50 FR at 49171-173 (Nov. 29,1985)
(partial burning for energy recovery is covered by section 3004(q) and Btu-rich wastes are
burned at least partially for that purpose).    .           '       .    .
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       Finally, only wastes that contain less than 500 ppm ic: : toxic organic constituents
listed in Appendix Vffl, Part 261, will be considered to recover metals. EPA believes that
it is important to have an objective measure to determine when burning is for metal
recovery, and that a 500 ppm level is within the zone of reasonable values that the Agency
could select for this purpose.  As noted in the supplemental proposal in a closely related
context, a 500 ppm level for total toxic organic constituents reasonably distinguishes
wastes destined for material recovery from wastes burned for nonrecovery purposes
because: (1) it represents a concentration of material far exceeding trace levels (generally
measured in single digit parts per million (ppm) or tens of ppm); (2) this level of hazardous
constituents could create an incremental health risk if burned inefficiently, or with
inadequate emission controls; and (3) this level is high enough to indicate that an objective
of burning is waste treatment - destroying nontrace level organics - as opposed to material
recovery. (The Agency's earlier proposal dealt with the question of when a waste might be
considered to be indigenous to an industrial furnace burning for material recovery, and
considered the issue of whether these devices were burning for a material recovery
purpose, and proposed the 500 ppm level adopted in this rule as a means of objectively
ascertaining that purpose. 54 FR 43731.)

       In order to be informed of persons claiming this deferral, and in order to decrease
potential abuse of the deferral, the Agency is requiring that all persons notify the Agency if
they assert that their smelting, melting, or refining furnaces are deferred from regulation
when burning hazardous wastes because the purpose of the activity is metal recovery. In
addition, all such persons have to keep records documenting the basis for the claim (i.e.,
that the wastes meet the  Btu and total toxic organic constituent thresholds, the wastes
contain recoverable levels of metals, and the device is indeed engaged in producing a metal
product for public use).  Sampling and analysis procedures specified in SW-846 must be
used to make these determinations. These conditions are consistent with existing 261.2(0
which requires that all persons claiming to be exempt or excluded from regulation because
of a recycling activity to have the burden of proof demonstrating that they are entitled to the
exemption or exclusion. In addition, the Agency notes that a consistent recommendation of
state and regional officials at the Agency's recent public meetings on the regulatory
definition of solid waste was to provide notification and recordkeeping so that regulatory
officials know that a person is operating in an exempt status in order to verify their claim.
The Agency is acting on these recommendations in this rule.
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      Hie Agency also notes that the derived from rule could apply to the residues from
metal recovery if metals are being recovered from listed hazardous wastes. EPA believes
this to be explicit from the remand in API v. EPA discussed earlier. The Court indicated
that the Agency's explanation for not establishing a treatment standard for the slag residue
from processing waste K061 was erroneous, and remanded the case to the Agency to
reconsider its explanation,  906 F.  2d at 740*42. Implicit (or perhaps explicit) in this
holding is the fact that the Court viewed the residue as a hazardous waste still coming under
me terms of the K061 land disposal prohibition (the Court referred repeatedly to "k061
slag" and mentioned the derived from rule as the basis for the slag being a hazardous
waste, id- at 742), at least until the Agency provides a different explanation as to why the
slag might not be a hazardous waste.  Thus, because EPA has not yet provided a new
explanation regarding the indigenous principle (as explained above), at the present time,
EPA views residues from metal recovery of listed hazardous wastes are considered to be
derived from treatment of hazardous waste and thus hazardous themselves unless some
other principle (such as the Bevill amendment, or in some cases, status under an authorized
state program) operates to achieve a different result

       Finally, the Agency notes that the deferral applies only to the furnace itself. The
hazardous waste is subject to transportation and storage controls prior to introduction into
the furnace.  See 266.100(c).

       The deferral of regulation of emission standards does  not apply to cement kilns,
aggregate kilns, and HAFs that bum hazardous waste for purposes other than energy
recovery. The Agency has studied these devices carefully and determined  that die
regulatory standards in today's rule are appropriate for  these devices when they bum
hazardous wastes for a purpose other than energy recovery.  Consequently, the Agency
sees no reason to defer emission standards for these types of units.

PART  THREE:    STANDARDS  FOR  BOILERS AND . INDUSTRIAL
FURNACES  BURNING HAZARDOUS WASTE

       Today's rule establishes controls for emissions of paniculate matter, toxic organic
compounds, toxic metals, and hydrogen chloride and free chlorine. Those controls are
discussed below.

       EPA notes that in some cases, today's rule potentially requires limitations on the
content of nonwaste input to a boiler or industrial furnace  that is burning hazardous waste.

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For example, compliance with the limits for metals, PM, and HCI/C12 requires controls not
only on the hazardous waste input but also potentially controls on other fuels and industrial
furnace feedstocks.  EPA has adopted this approach not to regulate the nonwaste input to
these devices, but rather to ensure that burning hazardous waste in the device does not pose
unacceptable risks to human health and the environment. These limitations function as
operating conditions on the unit to ensure compliance with the hazardous waste emission
standards.  For example,  unless limitations are established on  nonwaste parameters,
owners and operators could initially demonstrate compliance by burning clean raw
materials along with hazardous waste, and then change their raw material input in a manner
that causes emissions to increase significantly. In addition, the approach adopted today
allows owners and operators maximum flexibility in demonstrating compliance with the
emission standards by allowing adjustments to nonwaste input as a means of achieving
compliance.  The alternative of demonstrating compliance only through alteration of
hazardous waste feed is not only less flexible, but would create enormous administrative
difficulties (and add significant expense) for both regulated entities and Agency permit
writers.  (For example, stack monitoring  might no longer be a feasible  means of
demonstrating compliance because one could not ascertain what portions of the emissions
are attributable to burning hazardous waste.) For these reasons, we think the approach
adopted today is the most sensible means of demonstrating compliance.

I. Emission Standard for Particulate Matter

       Boilers and industrial furnaces that bum hazardous waste may emit substantial
quantities of paniculate matter (PM).  (Emissions of paniculate matter can have adverse
effects on human health and the environment even if toxics are not adsorbed on the
paniculate matter. However, the Agency's chief concern in this rule is control of adsorbed
toxics.) Because toxic metals and organic compounds may adsorb onto smaller size PM
that can be entrained in the lungs, unregulated paniculate emissions could pose a significant
threat to human health.  Although there may be limitations to the health-based standards,
the metals and organic emissions standards promulgated in today's  rule provide protection
of public health based on  current knowledge about  toxic pollutants and available risk
assessment methodologies. The PM control standard promulgated today will provide
additional protection by ensuring that adsorbed metal and organics are removed from stack
gas with the PM.

       In today's rule, EPA is establishing a standard for boilers and industrial furnaces
which limits paniculate emissions to 0.08 gr/dscf (grains/dry standard cubic foot) corrected

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m 7% oxygen. This limit was chosen because it provides a common measure of protection
from paniculate emissions from boilers, industrial furnaces, and incinerators burning
hazardous wane; This standard may be redundant for:  (1) a new, large capacity facility
assigned to a specific source category which is governed by a New Source Performance
Standard (NSPS); (2) a waste burning facility located in a non-attainment area subject to
State Implementation Plan (SIP) standards; (3) a facility with standards for metals and HC1
emissions that result in paniculate emissions below O.OS gr/dscf; and (4) a facility subject
to a stricter standard based on Best Available Control Technology (BACT) imposed
pursuant to the Oean Air Act's Prevention of Significant Deterioration (PSD) program. In
such cases, the device would be subject to the more stringent paniculate matter standard,
not the RCRA 0.08 gr/dscf standard, and the additional burden  of  demonstrating
compliance with the applicable paniculate matter standard concurrently with the applicable
emissions standards in today's rule for organic compounds, metals, and acid gases will not
be substantial. We believe, however, that there are many situations where a BIF is either
not currently subject to a paniculate matter standard, or the standard is higher than the
RCRA 0.08 gr/dscf standard.

       The Agency has considered lowering the paniculate standard to take advantage of
technology advances made in air pollution control and to be consistent with the proposed
standard of 0.015 gr/dscf for municipal waste incinerators. (We note that the proposed
standard for MWIs also served as a surrogate to control emissions of toxic metals. 54 FR
52219.  In contrast, today's rule has separate emission standards for each toxic metal.) We
are not prepared to do that at this time, however, because we have not conducted the
studies to establish an appropriate PM standard that represents  best demonstrated
technology (BDT). Although many boilers and industrial furnaces may be able to achieve a
PM standard lower than 0.08 gr/dscf (in fact, the PM NSPS for specific types of BIFs is
lower than 0.08 gr/dscf), we are not certain that all BIFs can meet a standard of 0.015
gr/dscf.  This is because some industrial furnaces have a  very high  (uncontrolled)
paniculate loading due to entrained particles of raw materials. Examples are cement kilns
and light-weight aggregate kilns. Hence, a single PM standard of 0.015 gr/dscf cannot
now be promulgated.

       The Agency firmly believes that the 0.08 gr/dscf PM standard, when used as a
supplement to the risk-based metal controls provided by today's rule, provides protection
of human health and the environment. Given that hazardous waste burned In BIFs could
contain virtually unlimited concentrations of toxic metals, the Agency believes that risk-
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 based standards arc needed to supplement the PM standard for hazardous waste burning
 irrespective of whether tbe PM standard represents best-demonstrated technology.  Even
 under a PM standard as low as 0.015 gr/dscf, a large fraction of the PM emitted from a
 hazardous waste combustion device could be comprised of toxic metals that could result in
 substantial health risk.

       Nonetheless,, ifce Agency will consider if additional PM controls are warranted to
 control emissions of toxic metals. In that evaluation, the Agency will consider whether the
 additional controls, if any, should be promulgated in the future under the new Clean Air
 Act  See discussion in section HI. A of Pan One of this preamble.  Finally, we note that
 permit writers also could impose a lower PM standard where facts warrant, pursuant to die
 omnibus permit authority in section 3005(c)(3).8

 A. Basis for Final Rule

       Paniculate matter (PM) is controlled from combustion sources to limit emissions of
 toxic metals and PM per  se (i.e., because of human health and ecological impacts
 associated with PM that does not contain toxic metals).  In the May 6,1987 proposed rule,
 EPA  suggested that a PM emission standard was not needed for boilers and industrial
 furnaces because the risk-based metals controls provide adequate control  of metals
 emissions.  The Agency reasoned that a standard intended to control PM per se would be
 more appropriately applied to these sources under authority of the Clean Air Act rather man
 RCRA.

       EPA received numerous comments on the May 6,1987 proposed rule suggesting
 the need for a paniculate standard for boilers and  furnaces burning hazardous waste. Many
 commenters believed that, notwithstanding the risk-based metals controls, unregulated PM
 emissions with adsorbed toxic metals and organic compounds could pose a significant
 health risk.  In addition, three commenters suggested that EPA  address the issue of
 paniculate control during soot-blowing cycles when levels of paniculate emissions are 4 to
 7.2 times the level of emissions under normal operation. The Agency carefully considered
 these comments and subsequently determined that the risk-based metals standards should
8      EPA notes that permit writers choosing to invoke the omnibus permit authority of
270.32(b)(2) to add conditions to a RCRA permit must show that such conditions are
support for the conditions to interested parties and accept and respond to comment In
addition, permit writers must justify in the administrative record supporting the permit any
decisions based on omnibus authority.

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be supplemented with a PM standard to provide a common measure of control for metals.
This decision was based in pan on a consideration of commenters' concerns about the
limitations of risk-based metals standards.  See 54 FR 43720-21.  Hence, the Agency
subsequently proposed a paniculate emissions standard of 0.08 gr/dscf (grains/dry
standard cubic foot) corrected to 7% oxygen in the October 26,1989 supplement to the
proposed role.  The standard would be applicable to all boilers and industrial furnaces not
governed by a more stringent (NSPS or SIP) standard.

       1.  Alternatives Considered.  In selecting the standard for boilers and industrial
furnaces, die Agency considered the following alternatives:. (1) apply the current NSPS
standard for steam generators burning waste; (2) apply the applicable NSPS; or (3) apply
the existing hazardous waste incinerator standard. These options are discussed in the 1989
supplemental notice (54 FR 43720).

       Many commenters supported the proposed paniculate standard of 0.08 gr/dscf.
Several commenters, however, opposed this limit, arguing against imposing a standard
appropriate for incinerators on boilers and furnaces. Still other commenters suggested that
the 0.08 gr/dscf limit did not go far enough in  protecting the public health. These
respondents argued for a lower limit comparable to that the Agency proposed for municipal
waste incinerators.

       The Agency continues to believe that the 0.08 gr/dscf PM standard, when used as a
supplement to the risk-based metal controls provided by today's rule, provides substantial
protection of human health and the environment

       2.  Basis for Standard. Today's rule promulgates the proposed paniculate emission
limit of 0.08 gr/dscf because, as a supplement to the risk-based metals controls, it provides
a common measure of protection from paniculate emissions  from boilers,  industrial
furnaces, and incinerators burning hazardous waste. In addition to providing control of
paniculate metals and adsorbed organic compounds, the 0.08 gr/dscf standard should also
ensure that the Clean Air Act's National Ambient Air Quality Standard (NAAQS) for
particulates is achieved in most cases. An analysis of existing sites shows that  emissions
of particulates at 0.08 gr/dscf could result in MEI levels of up to 30% of the maximum
daily PMjQ (paniculate matter under 10 microns) NAAQS (150 mg/m3). If background
paniculate levels at a site are high (i.e., the site is in a, non-attainment area), paniculate
emissions from the device should also be addressed as pan of the State Implementation
Plan (SIP) (as they are now for hazardous waste incinerators in paniculate non-attainment
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areas). Therefore, although the 0,08 gr/dscf standard may not ensure compliance with the
NAAQS in every situation, this issue will be addressed by the SIP since the facility would
be, by definition, in a non-attainment area for paniculate emissions.

B. Interim Status Compliance Procedures

       Facilities operating under interim status must comply with the PM emission
staadanL By the effective date of the rule, owners/operators must submit a certification of
precompliance tnat documents their use of engineering judgment to show that, considering
feed rates of ash from all feed streams, partitioning of ash to bottom ash or product, and the
PM removal efficiency of the air pollution control system (APCS), PM emissions are not
likely to exceed the 0.08 gr/dscf limit.  Owners and operators must also establish and
provide with the precompliance certification limits on feed rates of ash in all feed streams
consistent with those used to determine that emissions of paniculate matter are not likely to
exceed the standard. The facility may not exceed these feed rates during interim status
(unless amended by a revised certification of precompliance). Further, within 18 months
(unless extended) of promulgation, owners/operators must conduct emissions testing and
certify that emissions do not exceed the limit.  See section Vn in Part Three of this
preamble for more information.

C. Implementation

       Owners/operators must demonstrate  compliance with the PM standard using
Methods 1-5 of 40 CFR Part 60, Appendix A.  The compliance test for certification during
interim status and the trial burn for facilities applying for a RCRA operating permit must be
representative of worst-case operating conditions with respect to paniculate emissions that
will occur during operation of the facility (i.e., because limits on operating conditions
applicable for the remainder of interim status will be based on operating conditions during
the compliance test).

       The PM standard is implemented by  limiting the feed rate of ash from all feed
streams (i.e., hazardous waste, other fuels, raw materials) and by limits on APCS-specific
operating parameters.  The limits are established  during interim status based  on the
                 i
compliance test, and in the operating permit based on the trial bum.

       The final rule gives special consideration to cement and light-weight aggregate kilns
because their raw material feed streams contain the vast majority of the ash input and
resulting PM. Therefore, owners/operators of cement kilns and light-weight aggregate

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kilns are not required to monitor ash feed rates of feedstreams. We emphasize, however,
that cement kilns and lightweight aggregate kilns, like all BIFs, are still required to
demonstrate confbnnance with the PM emission standard during a compliance test (under
interim status) or trial burn (under a Part B application).  The Agency believes that the
capacity limit on the facility (expressed in appropriate units such as raw material feed rate)
and the limits on the air pollution control system (APCS) operating parameters applicable
during both interim status and under a subsequent operating permit will ensure that cement
and light-weight tains continuously comply with the PM standard 9

IL  Controls for Emissions  of Toxic Organic Compounds

      Burning hazardous waste that contains toxic organic compounds (i.e., organic
compounds listed in Appendix VIII of 40 CFR Part 261) under poor combustion
conditions can result in substantial emissions of the toxic compounds originally present in
the waste as well as other compounds, due to partial but incomplete combustion of the
constituents in the waste. The quantity of toxic organic compounds emitted depends on the
concentrations of the  toxic compounds in the  waste, the waste firing rate  (i.e., the
percentage of total fuel provided by the hazardous waste to the boiler or industrial furnace),
and the combustion conditions under which the waste is burned. The risk posed by the
emissions depends on the quantity and toxicity of the compounds emitted and on the
ambient levels to which persons are exposed. Hypothetical risk assessments show that
under poor combustion conditions that achieve only 99 percent or 99.9 percent destruction
and removal efficiency (DRE) of organic compounds, risks to the maximum exposed
individual (MEI) from unbumed carcinogenic organics found in hazardous waste can result
in increased lifetime cancer risks of 1(H.10

      The Agency is controlling the emissions of toxic organic compounds from boilers
and industrial furnaces that bum hazardous waste with two performance standards. Fust, a
99.99 percent destruction  and removal efficiency (DRE) standard for principal organic
hazardous constituents (POHCs) in waste feeds will ensure that constituents in the waste
9     We note, moreover, that some boilers and many industrial furnaces are already
subject to a particulate matter (PM) standard under a NSPS, SIP, or PSD program and the
applicable PM standard is generally more stringent than the 0.08 gr/dscf standard provided
by today's rule. Thus, these devices are already under a regulatory compliance program
for a PM standard. We note further that the more stringent PM standard applies.
      Engineering-Science, Background Information Document for the Development of
Regulations to Control the Burning of Ha7flTdous Waste in Boilers and Industrial Furnaces.
Volume ffl, January 1987 (NTIS # PB  87 173845).

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are not canned it levels that could pose significant risk in virtually all scenarios of which
the Agency is aware.11  Second, limits on flue gas concentrations of carbon monoxide
(CO) and, where specified, hydrocarbons (HC) will ensure that combustion devices
operate continuously at high combustion efficiency and emit products of incomplete
combustion (PICs) at levels that will not pose adverse effects on public health and the
environment.  The basis for these standards is discussed below.

A. DRE Standard.

       As proposed, the Agency is promulgating a 99.9999% DRE standard12 for those
acutely hazardous wastes listed because they contain dioxin13 (and waste mixed with those
wastes), and  a 99.99 percent DRE performance standard for all other wastes.  This
standard is protective, it can be readily achieved by boilers and industrial furnaces, and it
will ensure that the Agency's controls are consistent for all combustion devices (boilers,
industrial furnaces, and incinerators) that pose similar risks.

       Hypothetical risk assessments have shown that a 99.99 percent DRE standard for
POHCs is protective of risks posed by emissions of organic constituents in the waste in
virtually every scenario of which the Agency is aware.14 (EPA considers elsewhere in this
notice the issue of products of incomplete combustion.) Increased lifetime cancer risks to
the maximum exposed individual (MEI) from an incinerator  operating at 99.99 percent
DRE would  generally be 10'6 or less.  Threshold (i.e., noncarcinogenic) organic
compounds also would not be expected to be present in emissions from hazardous waste
burned in boilers and industrial furnaces at levels that could pose a health hazard under the
99.99 percent DRE standard.

       EPA is aware, however, that the DRE standard does not directly control the mass
emission rate  (e.g., pounds per hour) of unburned toxic organic constituents in  the waste.
Although there are hypothetical situations in which risks from POHCs could  be significant
under a 99.99 percent DRE standard (e.g., boilers or industrial furnaces located in urban
areas burning high volumes of waste with  high  concentrations of highly potent
carcinogenic  organics), the Agency is not aware that any such situations are actually
11    Except that 99.9999% DRE is required for dioxin-listed hazardous waste.
12    The proposed formula for calculating DRE has been revised in die final rule (see
266.104(a)) to make it mathematically correct considering use of significant figures.
13    EPA Hazardous Wastes FO20, FO21, FO22, FO23, F026, and FO27.
I*    Engineering Science, op. tit

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     ling. If, however, during the permit process, it appears that a high-risk scenario may
exis, permit officials may use the omnibus permit authority15 of Section 3005(c)(3) of the
Resource Conservation and Recovery Act (RCRA) codified at 270.32(b)(2) to develop
permit requirements, as necessary, to protect human health and the environment (e.g., by
requiring a 99.9999 percent DRE, by limiting the feed rate of particular toxic compounds,
or by setting a mass emissions rate).

       1.  Selection of POHCs for DRE Testing.  In the April 27,1990 proposed rule to
amend the incinerator standards (55 FR 17890), EPA outlined the considerations to be
made by applicants and permitting officials in selecting POHCs for DRE trial burns. Given
that the DRE implementation procedures for boilers and industrial furnaces (BIFs) are
identical  to those for incinerators, the discussions in the incinerator proposed rule are
pertinent to this rule.

       A major factor in selecting a POHC for DRE testing is its incinerability relative to
other toxic organic compounds. A number of indices can be used to predict incinerability
including heat of combustion, autoignition temperature, thermal stability under excess
oxygen conditions, and thermal stability under low oxygen (substoichiometric) conditions.
An incinerability ranking based on thermal stability at low oxygen  concentrations
(TSLoO2) shows promise and is currently seeing widespread use in incinerator permits. A
number of commenters responded to EPA's request for comment on the use of the TSLoO2
index for POHC selection.  In general, they raised no problems with use of the index.
Their main concern appeared to be that EPA choose one index and apply it consistently.

       The Agency, however, is not requiring the use of a particular index. Due to the
various "failure  modes" different organic compounds are susceptible to during the
destruction process in a combustion device, and the evolving state of knowledge in this
area, the Agency feels that the POHC selection process is technically complex, and that it
should involve a  number of considerations, rather than simply one incinerability ranking.
Thus, EPA instead recommends that permit writers and applicants consider these indices
and other relevant factors and use then-judgment and applicable guidance on a case-by-case
basis to select POHCs for the trial bum.
15     EPA notes that permit writers choosing to invoke the omnibus permit authority of
270.32(b)(2) to add conditions to a RCRA permit must show that such conditions are
necessary to ensure protection of human health and the environment and must provide
support for the conditions to interested parties and accept and respond to> comment In
addition, permit writers must justify in the administrative record supporting the permit any
decisions based on omnibus authority.

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       2. Use ofPOHC Surrogates. A number of laboratory-scale, pilot-scale, and field-
 scale tests have been conducted to investigate the use of nontoxic tracer surrogates (e.g.,
 sulfur hexafluoride (SFg)) rather than POHCs selected from Appendix VHI of Pan 261.
 Sulfur hexafluoride, in particular, shows promise as a conservative tracer surrogate for
 compounds which are susceptible to the thermal failure mode (i.e., it is difficult to destroy
 unless sufficiently high temperatures are reached). It is readily available commercially, and
 is inexpensive and nontoxic.  POHCs that are listed on Appendix Yin, especially in
 situations where spiking is required to increase concentrations in a waste for ORE testing,
 are often difficult to obtain, are expensive, and are a health hazard to operators. Sampling
 and analysis techniques for SE$ are well documented because of its long use as a tracer gas
 for monitoring ambient air and are more straightforward (simpler) and less expensive than
 sampling techniques for Appendix Vm, Part 261, compounds (e.g., YOST and MM5).

       Numerous commenters responded to EPA's request for information on an approach
 for simplifying and standardizing DRE testing. Commenters supported standardization of
 DRE testing provided the approach is equitable for all boilers, industrial furnaces, and
 incinerators. Comments were received in support of all three approaches proposed by EPA
 ("POHC soup," surrogates, and specific waste analysis). Commenters generally supported
 use of surrogates in  lieu of extensive waste analysis for design of DRE tests.  Other
 commenters suggested using a limited number of major waste constituents as POHCs, such
 as carbon tetrachloride, perchloroethylene, trichloroethylene, and monochlorobenzene,
 until it can be shown that a universal surrogate, such as sulfur hexafluoride (SF$), is
 comparable in demonstrating DRE performance. Sulfur hexafluoride was recommended by
 some commenters as a good surrogate choice based on the high accuracy of results with the
 compound and ease of use.

       However, since the April 27 proposed rule, data have become available  showing
 cases where other organic compounds were more difficult to destroy than SFfi under
 conditions of low oxygen.  This is consistent with theory, since S?6 can be destroyed
under conditions of high temperature and low oxygen relatively easily compared to
compounds which need oxygen to decompose.  Thus, although S?6 appears  to show
promise as a surrogate for testing the thermal failure mode because of its stability at high
temperatures, it does not appear to be adequate as a "universal" surrogate, since it does not
test for low oxygen or "mixing" failure.
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       Nevertheless, today's rule  explicitly allows the use of surrogate, nontoxie
compounds for selection as POHCs for DRE testing.  As for any other type of POHC, the
use of such compounds must be approved on a case-by-case basis by permit officials based
on technical support provided by the applicant  The applicant's trial bum plan must
adequately document the correlation between the DRE of the surrogate compound and the
DREs of the Appendix VKI compounds anticipated to be burned at the facility under the
facility's permit

       3.  Waiver of DRE Trial Burn for Boilers Operating Under the Special Operating
Requirements  In  1987, the Agency proposed to waive the trial burn requirement to
demonstrate DREs for boilers that operate under special operating requirements (SOR).
The  SOR required that, in addition  to meeting the proposed 100  ppmv CO limit a
qualifying boiler must:  (1) burn at least 50 percent fossil fuel in the  form of oil, gas, or
coal; (2) operate at a load of at least 25 percent of its rated capacity;  (3) bum hazardous
waste fuel with an as-fired heating value of at least 8,000 Btu/lb; and (4) inject the
hazardous waste fuel through an acceptable atomization firing system.

       The SOR were based on the results of nonsteady-state boiler testing. From these
results, the Agency believed that boilers operating under the SOR would maintain a hot
stable flame conducive to maintaining high combustion efficiency, resulting in maximum
destruction of organic constituents in the hazardous waste fuel. The Agency believed that
these boilers would achieve at least 99.99 percent DRE, and therefore, a trial burn to
demonstrate DRE would not be necessary.

       The Agency continues to believe that boilers operating under the SOR will achieve
99.99 percent DRE. However, based on comments received on the proposed SOR and on
further examination of the previous steady-state and nonsteady-state boiler test results, the
Agency has made the following modifications to the SOR:

   (1) limit eligibility for the waiver to nonstoker, watertube boilers;
   (2) revise the requirement that the boiler fire 50 percent fossil fuel or fuels derived from
       fossil fuel to include tall oil, to allow permit officials to approve on a case-by-case
       basis other nonhazardous fuels with combustion characteristics comparable to fossil
       fuel, and to require for all such primary fuels (i.e., fossil fuels, tall oil, and other
       fuels approved on a case-by-case basis) a minimum heating value of 8,000 Btu/lb;
                                       40

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    (3) clarify that the hazardous waste fuel fired must have an as-fixed heating value of
       8,000 Btu/lb and require that each fuel fired in the burner where hazardous waste is
       fired must have an as-fired healing value of 8,000 Btu/lb;
    (4) increase die minimum load requirement from 25% to 40%; and
    (5) eliminate the lower viscosity requirements for the hazardous waste and decrease the
       upper viscosity limits for the hazardous waste to 300 seconds, Saybolt Universal
       (SSU), measured at the as-fired temperature of the fuel.
                                                            f
       As proposed in 1987, boilers with a trial burn waiver under the SOR must meet the
 Tier I CO limit of 100 ppmv16 and must comply with all other requirements of the final
 rule (e.g., metals standards, PM limit).

       The revised SOR are presented below, along with the basis for die revisions.

       a. The Boiler Must Be a Nonstoker, Watertube Boiler.  Commenters stated that the
 nonsteady-state testing of only three stoker and firetube boilers is insufficient to determine
 whether 99.99 percent DRE would always be achieved under the SOR. Commenters also
 maintained that the stoker and firetube boilers tested were not representative of all types and
 sizes.

       The Agency agrees that there is limited data demonstrating that stoker and firetube
 boilers can achieve 99.99% DRE under die SOR. In the Agency's steady- and nonsteady-
 state testing, only three firetube boilers and one stoker boiler were tested under steady-state
 conditions, and one stoker boiler was tested under nonsteady-state conditions.  The
 remainder of the boilers tested were watertube boilers.

       The results from one of the firetube boiler tests generally support the  ability of
 firetube boilers to achieve 99.99 percent DRE, but  this boiler was specially designed to
 combust hazardous waste.  The Agency is concerned whether more conventionally
 designed firetube boilers could easily achieve this level of DRE. DREs could not be
 calculated at one of die other firetube boiler tests due to inadequate waste feed levels, and
 sampling and analytical problems occurred at the third firetube boiler test  The stoker boiler
 tested under steady-state conditions did not demonstrate 99.99 percent DRE. In addition to
 die limited data for these boiler types, a greater potential exists for poor distribution of
16     Boilers complying with the Tier E PIC controls where CO levels exceed 100 ppmv
are not eligible for the automatic waiver of the DRE trial bum.  This is because die DRE test
data used to support die waiver was obtained for boilers operating at CO levels below 100
ppmv.
                                       41

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combustion gases and localized cold spots in firetube and stoker boilers that can result in
poor combustion conditions. This is because these boilers generally bum fuels with a large
and variable particle size on a bed, thus, making even distribution of combustion air
difficult Therefore, the final rule precludes stoker or firetube boilers from the automatic
waiver of a DRE trial bum.

      b. A Minimum of SO Percent of the Fuel fired to the Boiler Must Be High Quality
"Primary" Fuel Consisting of Fossil Fuels or Fuels Derived From Fossil Fuels, Tall Oil,
or, if Approved on a Case-By-Case Basis, Other Nonhazardous Fuel Comparable to Fossil
Fuel, and All Such Primary Fuels Must Have a Minimum As-Fired Heating Value of 8,000
Btu/lb.  Thirteen commenters found the SO percent fossil fuel requirement to be overly
restrictive.  In particular, one commenter proposed that the requirement be rephrased to
allow the burning of no more than SO percent hazardous waste in mixtures such that
nonhazardous waste fuel supplements can be fired.  Another commenter suggested
eliminating the fossil fuel requirement for wastes that have heating values comparable to
fossil fuels.  Eleven commenters supported the burning of high quality non-fossil fuels,
such as tall oil (i.e., fuel derived from vegetable and rosin fatty acids) and the by-products
derived from the fractional distillation of tall oiL Many of these commenters said they have
burned these materials and claimed they have heating values and combustion characteristics
similar to fossil fuels. Three commenters requested that the burning of wood wastes as a
primary fuel be allowed. One of these commenters presented the results from six trial
burns for wood waste boilers which demonstrated that combustion zone temperatures in
these types of boilers are consistent, and that a hot, stable  flame conducive to the
destruction of organic constituents in the waste is present under these conditions.

      Based on the comments and information presented regarding the use of tall oil (i.e.,
tall oil bums like commercial fuel oil), the Agency is revising the 50% primary fuel
requirement to include tall oil..  Also, the Agency believes that the combustion of other
nonhazardous fuels that have heating values of at least 8,000 Btu/lb (representing the lower
heating value range of most sub-bituminous coals), and combustion characteristics similar
to fossil fuels, will ensure a hot, stable flame conducive to the destruction of organic
constituents in the waste.  An owner/operator who is planning to burn such a fuel
supplement must present information on the supplement's combustion characteristics for
the Director's review. Concerning wood wastes, the Agency continues to believe mat these
wastes may not provide the hot, stable combustion zone conditions needed to achieve
99.99 percent DRE, Due to the higher flue gas moisture, excess air, CO levels, and lower
                                       42

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furnace temperatures associated with wood firing, the potential for less than 99.99 percent
DRE exists. Therefore, boilers that fire wood wastes must demonstrate DRE capabilities
through a trial bum.

       The SO percent minimum primary fuel requirement, on a total heat or volume input
basis, whichever results in the greater volume of primary fuel, also is needed to ensure
appropriate combustion zone conditions. This limit was based on the maximum levels of
hazardous waste burned in die boilers tested by EPA under nonsteady-state conditions.

       Finally, the Agency recognized that the term "fossil fuel" can include peat or other
fuels with heating values below 8,000 Btu/lb.  Because the test data used to support the
waiver were from boilers fired with primary fuels with heating values higher than 8,000
Btu/lb, the final rule applies the minimum 8,000 Btu/lb as-fired heating value limit to all
fuels, including fossil fuels, used to meet the minimum 50% primary fuel requirement

       c.  Boiler Load Must Be at Least 40 Percent. Several commenters addressed the
proposed minimum load level of 25 percent  Only one commenter considered it to be too
low. This commenter advocated an 80 percent load requirement unless high efficiency
combustion can be demonstrated at the trial burn.  One commenter considered the 25
percent requirement  to be arbitrary, but within current practice.  Another commenter
recommended that the level be more flexible for multiple burner boilers. One commenter
recommended that the requirement to maintain a boiler load of 25 percent be eliminated if
the Btu value of the wastes burned is equivalent to that of coal thereby providing the heat
input necessary to sustain normal combustion operations.

      Boiler testing conducted at a load as low as 26 percent has demonstrated that certain
boilers can achieve 99.99 percent DRE when operated at low loads. However, due to
concerns related to flame stability, combustion control, and heat transfer effects associated
with load turndown on some boilers, the Agency has raised the boiler load limit from 25
percent to 40 percent of design load.  Operation of some boilers at loads of less than 40
percent can result in significantly higher excess air levels and localized decreases in flame
temperatures. In addition, most of the boilers tested to develop the operating requirements
operated at loads above 40%.  Therefore, limiting the boiler load to 40% is more consistent
with the available test data. If an owner/operator expects to operate a unit at a lower load
while firing hazardous waste, a trial burn to demonstrate 99.99 percent DRE is required.
                                      43

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       d. The Heating Value of the Hazardous Waste Fuel Must Be a Least 8,000 Btu/lb,
 As-Fired, and Each Fuel Fired in a Burner Where Hazardous Waste Is Fired Must Have a
 Heating Value of at Least 8,000 Btu/lb, As-Fired.  Eleven commenters expressed concern
 that the "as-fired" requirement proposed in 1987 will require the blending of wastes that
 have heating values of less than 8,000 Btu/lb with other wastes and/or the primary fuel
 before atomization. Four commenters documented a number of problems with blending
 low Btu wastes, including immiscibility and other mixing problems, increased quantity of
 materials requiring handling, difficulty of controlling feed during  unit  upsets, and
 impracticality for coal-fired systems. Five commenters requested that the heating value be
 determined on a total-burner basis, as a composite of primary fuel and waste.  Three
 additional commenters recommended that the minimum heating value of wastes be lowered
 to 5,000 Btu/lb.

       The Agency agrees that waste fuel blending can present problems in some
 instances.  However,  the Agency is concerned that allowing low Btu wastes to be fired
 separately from the fuel and then atomized in the flame region of the burner might make it
 difficult to ensure good atomization, proper feed system operation, and, consequently,
 adequate combustion  of the hazardous waste. Therefore, the 8,000  Btu/lb requirement,
 which represents the lower range of heating values of fossil fuels, applies to the as-fired
 heating value of the hazardous waste and to the as-fired heating value of any other fuel fired
 in the same burner with the hazardous waste.17

       If hazardous waste with a heating value below 8,000 Btu/lb18 is  mixed with the
 "primary" fuel to meet the as-fired minimum heating value for hazardous waste of 8,000
 Btu/lb, mat quantity of primary fuel may not be counted toward the 50% primary fuel
 requirement This is because the purpose of requiring 50% of the fuel to be "primary" fuel
 is to ensure a hot, stable flame to combust the hazardous waste. If a portion of the primary
 17    We note that the 8,000 Btu/lb minimum heating value also applies to the "primary"
 fuel that must comprise at least 50% of the boiler's fuel requirements. However, the
 remainder of the boiler's fuel requirements may be provided by hazardous waste and other
 fuels.  There are no restrictions on the other fuels unless they are fired in the same burner
 with the hazardous waste. In that case, those other fuels, like the hazardous waste and
' "primary" fuel, must have a minimum heating value of 8,000 Btu/lb.
 1    We note mat, as discussed elsewhere in the text, the sham recycling policy stays
 into effect until an existing facility certifies compliance with the emissions standards (see
 6266.103(c)). Thus, until that time, hazardous waste burned in a BIF must have an as-
 generated heating value of 5,000 Btu/lb, unless the waste is burned solely as an ingredient
                                        44

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fuel is blended with the hazardous waste to increase the heating value of the hazardous
waste as-fired, then that portion of the primary fuel is not providing the hot, stable flame.

       The following example shows how this requirement will work. Suppose a boiler is
fired with 70% primary fuel and 30% hazardous waste, and that half of the primary fuel is
blended with the hazardous waste to achieve an as-fired heating value of 8,000 Btu/lb.
This boiler would not be eligible for the automatic waiver of the DRE trial bum because it is
fired with only 35% primary fuel (half of the 70%) that is not blended with the hazardous
waste to meet the minimum as-fired heating value limit of 8,000 Btu/lb.

       e.  The Hazardous Waste Must Be Fired with an Atomization System.  Seven
commenters argued that lower viscosity limits are unnecessary. Three commenters stated
that it is common to atomize wastes well below 150-200 SSU, and that No. 2 oil has a
viscosity of 32.6-37.9 SSU at 100F. One commenter indicated that the upper viscosity
limits appear high for the atomization systems specified.  One commenter disagreed and
said that the high limits are in the correct range. Six commenters expressed concern that the
particle size limits are overly restrictive. One commenter stated that diverse waste streams
can be handled to achieve good destruction without particle size limits. Another commenter
disagreed with EPA by stating that they are not familiar with nozzles designed for particle
sizes as small as 200 mesh. Three commenters said the waste viscosity should be left to
the discretion of the owner/operator since it is industry practice to operate at viscosities
which provide optimum atomization.

       Based on the commenters'  arguments, the Agency has eliminated the lower
viscosity requirements and reduced the upper limit to 300 SSU  (Seconds, Saybolt
Universal) measured at the as-fired temperature of the hazardous waste. We eliminated the
lower level because, after consideration of comments and re-evaluation, we believe that the
concern stated at proposal - formation of a fog at low viscosity levels which could result in
poor combustion conditions - is not likely to occur. At proposal, the Agency established
upper viscosity limits ranging  from 300  to  5,000  SSU, depending on the type of
atomization system. Commenters noted that, as a practical matter, wastes with as-fired
viscosities greater than 300 are not fired in an atomization system.  These modifications
will give facilities the flexibility  to preheat wastes before atomization and are consistent
with general industry practice for good atomization.

       Regarding particle size limits the final rule establishes the proposed limits. When
high pressure air or steam atomizers, low pressure atomizers, or mechanical atomizers,
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70% of the waste must pass a 200 mesh (74 micron) screen. When a rotary cup atomizer is
used, 70% of the waste must pass a 100 mesh (ISO micron) screen. These mesh sizes are
         with the design droplet size of the atomizers.
       Owners/operators of boilers who propose to fire hazardous waste outside these
viscosity and particle size limits must conduct a DRE trial bum.

B. PIC Controls.

       The burning of hazardous waste, like virtually any combustion process, results in
emissions of incompletely burned organic compounds, or products of incomplete
combustion (PICs). PICs can be unburned organic compounds that were present in the
waste, thermal decomposition products resulting from organic constituents in the waste, or
compounds synthesized during or immediately after combustion.  If a device is operated
under poor combustion conditions, substantial emissions of PICs can result (even if
99.99% DRE is demonstrated for POHCs; this just means that the POHC is not being
emitted in its original form).  However, it should be noted that estimates of risk to public
health resulting from PICs, based on available emissions data, indicate that PIC emissions
do not  pose significant risks when BIFs and incinerators are operated under good
combustion conditions.

       Nonetheless, the Agency is concerned about the potential health risk from PICs
because die available information has serious limitations. It is very difficult to identify and
quantify emissions of thousands of different compounds, some of which are present in
minute quantities. Although elaborate and expensive sampling and analytical techniques
have been developed that can identify many PICs, many others cannot be identified and
quantified with current techniques. Further, health effects information adequate to conduct
a health risk assessment considering exposure via direct inhalation is not currently available
on many organic compounds that may be emitted from combustion.systems. Finally, the
available public health and environmental risk assessment tools are incomplete. Data are
currently available to conduct indirect exposure analyses (e.g., exposure via the food chain,
drinking water, dermal exposure) on only a few organic compounds, and it will be some
time before the Agency will be able to quantify impacts on ecological resources on a site-
specific basis for purposes of establishing emissions standards.
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       Given the limited information about the hazards that PIC emissions may pose, EPA
believes it is prudent to require that boilers and industrial furnaces operate at a high
combustion efficiency to minimise PIC emissions.

       EPA is promulgating today a two-tiered approach to control PICs as discussed in
the October 29,1989, supplemental notice (54 FR 43721-28). Under Tier I, CO is limited
to 100 ppmv. Under Tier H, the Agency is providing an alternative standard. The facility
need not meet the 100 ppmv CO limit provided the facility can demonstrate that the
hydrocarbon (HC) concentration in the stack gas does not exceed a good operating practice-
based limit of 20 ppmv. The alternative CO limit under Tier n must be established during
the test bum based on the average over all runs of the highest hourly rolling average for
each run.

       1.  Use of a CO Limit to Control PICs. Generally accepted combustion theory
holds that low CO flue gas levels combined with low excess oxygen levels indicate a
boiler, industrial furnace,  or incinerator is operating at high combustion efficiency.
Operating under high combustion efficiency helps to ensure minimum emissions of
unburned (or incompletely burned) organics.  In the first stage of the combustion of
hazardous waste fuel, the POHCs thermally decompose in the flame to form other, usually
smaller, compounds termed products of incomplete combustion. In this first  stage of
combustion, these PICs also decompose to form CO.

       The second stage of combustion involves the oxidation of CO to CO2 (carbon
dioxide).  The CO to CO2  step is the slowest (rate-controlling)  step in the combustion
process because CO is considered to be more thermally stable (difficult to oxidize) than
other intermediate products of the combustion of hazardous waste constituents.  Because
fuel is being fired continuously, these combustion stages occur simultaneously.

       Thus, in the waste combustion process, the "destruction" of POHCs is independent
of flue gas CO levels.  CO flue gas levels cannot be correlated with DREs for POHCs, and
may also not correlate well with PIC destruction. Although some emissions data indicate a
weak correlation  between CO and PICs, the data generally indicate that there is a
relationship between the two parameters:  when CO is low, PIC emissions are relatively
low. The converse may not hold: when CO is high, PICs may or may not be high.

       Low CO is an indicator of the status of the CO to COj conversion process, the last
rate-limiting oxidation process;  Because oxidation of CO to CO2 occurs after the
                                      47

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destruction of a 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, is an indication of the failure of the PIC and POHC destruction process.

       EPA believes it is necessary to limit CO levels to levels that are indicative of high
combustion efficiency because (he precise CO level that indicates significant failure of the
PIC and POHC destruction  process is not known.  In fact, this critical CO level may
depend on site-specific  and  event-specific factors (e.g., fuel type, fuel mix, air-to-fuel
ratios, and the rate and extent of changes in these and other factors that affect combustion
efficiency). EPA believes that limiting CO levels is also  reasonable because: (1) it is a
widely practiced approach for monitoring combustion efficiency  - some boilers and
industrial furnaces are already equipped with CO monitors, and many are equipped with
flue gas oxygen monitors; (2) the monitors may pay for themselves through fuel savings
resulting from operation of the boiler or industrial furnace closer to maximum combustion
efficiency; and (3) well-designed and well-operated boilers and industrial furnaces can
readily be operated in conformance with either the  100 ppmv CO limit under Tier I, or the
20 ppmv HC limit under Tier IL

       2.  Tier 1 PIC Controls: 100 ppmv CO Limit.

       a.  Basis for the 100 ppmv CO Limit  The May 6,1987 proposed rule would have
applied the same CO emission limits to all boilers and industrial furnaces:  a lower limit of
100 ppmv over an hourly rolling average and a 500 ppmv limit over a 10-minute rolling
average. The hazardous waste feed would be shut off automatically if either limit was
exceeded However, the hazardous waste would be cutoff immediately once the 500 ppmv
limit was exceeded while the  waste feed would be cutoff within 10 minutes if the 100 ppmv
limit was exceeded. Further if the hazardous waste feed was cutoff more than 10 times in a
month, the proposed rule would have prohibited further hazardous waste burning pending
review and approval by enforcement officials.  The lower limit of 100 ppmv was selected
as representative of steady-state  high efficiency combustion conditions resulting in PIC
emissions that would not pose a significant risk. The higher limit of 500 ppmv was
proposed to limit the frequency of emission spikes that  inevitably accompany routine
operational "upsets," such as load changes and start-ups of waste firing.

       While two commenters stated that the proposed 100 ppmv CO limit is arbitrary, six
commenters supported the Tier I CO limit of 100 ppmv. One commenter supported both

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 the 100 ppmv CO limit over an hourly rolling average, and the 500 ppmv CO limit over a
 10-minute rolling average. Three additional commenters also expressed support for the
 500 ppmv CO limit over a 10-minute rolling average. Three other commenters supported a
 500 ppmv CO limit over an hourly rolling average, and stated that a maximum 1,000 ppmv
 CO limit can be included in addition to a 10-minute average.

       Many commenters opposed the CO trigger limits and associated limits on the
 number of waste feed cutoffs proposed in May 1987. Primarily, commenters objected to
 one set of CO emission limits as applicable to all boilers and industrial furnaces. Further,
 they argued that PIC emissions will not be significant if, when the waste feed is cutoff, the
 combustion chamber temperatures are maintained while the waste remains in the chamber.
 Six commenters argued that the trigger limits will result in increased NOX emissions.  One
 commenter stated that NOX and CO cannot be lowered simultaneously, and added that
 many low NOX boilers may not be able to meet these CO limits. As an alternative, one
 commenter stated that a higher Tier I CO limit should be allowed for less toxic emissions;
 however, this commenter did not provide an alternative approach for identifying the toxicity
 of emissions. One commenter suggested that  EPA retain two alternatives to  the CO
 standard:  establishing an alternative standard based on noiimethane, ethane hydrocarbon
 (NMEHQ emissions, and a case-by-case risk assessment approach.

       As  a result of these and other comments and further evaluation, EPA  is
 promulgating the Tier I limits based on a maximum hourly rolling average CO limit of 100
ppmv, corrected to 7 percent flue gas oxygen content  If this limit  is  exceeded, the
hazardous waste feed must be automatically and immediately cutoff. The  final rule does
not restrict the  number  of waste feed  cutoffs because:   (1) combustion chamber
temperatures must be maintained after a cutoff; and (2) the number of cutoffs will be
minimi7.ed by allowing CO concentrations to be averaged over a 60-minute period (i.e., the
hourly rolling average) and by the recommended use of pre-alanns to provide time  to
remedy the problem or to allow a staged waste cutoff before reaching the CO limit.
Nonetheless, the Agency retains the authority to limit the frequency of cutoffs as the facts
warrant  See 266.103(e)(7)(ii).  The final rule  does not include the proposed 500 ppmv
rolling average over a 10-minute limit on CO because we do not believe it is needed given
that the final rule requires immediate waste feed cutoff when the 100 ppmv hourly rolling
average limit is exceeded.  In addition, several commenters argued that the 500 ppmv limit
was arbitrary.
                                      49

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      In addition, EPA is promulgating alternative (Tier n) standards (discussed below),
as discussed in the October 1989 supplemental notice, for control of PIC emissions from
boilers and industrial furnaces. The Agency believes that the alternative controls will allow
facilities flexibility in meeting both the PIC controls and NOX emissions standards
(imposed under different regulatory authorities) simultaneously. The Agency believes that
the alternative, Tier n standards for control of PIC emissions are needed to address issues
and concerns raised by commenters on the proposed rule.

      The 100 ppmv CO limit promulgated today for Tier I is indicative of steady-state
(i.e., normal), efficient combustion conditions. The time-weighted average for the CO
limit is provided to accommodate the CO spikes that inevitably occur during routine
"upsets," such as when hazardous waste fuel firing starts, when there is a load change on
an industrial boiler, or when the composition of fuels varies. Given that CO is a sensitive
indicator of overall combustion conditions, and that it may be a conservative indicator of
POHC and PIC destruction, EPA is implementing CO control limits based on time-
weighted averages of exceedances rather than implementing fixed CO limits. Fixed limits
that do not acknowledge inevitable CO spikes and that do not give owners and operators
time to adjust combustion conditions actually  could result in greater emissions of PICs
because each time hazardous waste firing is interrupted, CO concentrations increase, and
emissions of incompletely burned organics may also increase. (Note, however, that there
is a requirement to maintain combustion chamber temperature after a waste feed cutoff
while waste remains in  the chamber that is intended to minimize HC emissions after a
cutoff.) Thus, any controls on CO must balance the effects of organic emissions that may
result from overly stringent CO limits that require frequent waste feed interruptions with the
effects of emissions resulting from less stringent controls that acknowledge inevitable CO
spikes.
                                                                       /
      The Agency has considered whether die  100 ppmv CO limit is, in fact, too stringent
given that we acknowledge the limit was chosen from within the range of reasonable values
that may be considered indicative of good combustion conditions  50 to 250 ppmv. We
attempted to obtain CO/time profiles from a number of well-operated devices to determine
the percentage of time die facilities operated within particular CO ranges.1? We thought to
use this data to predict the frequency of waste feed cutoffs that would be required at various
19     Energy and Environmental Research Corporation, "Guidance on Metal and PJC
Emissions from Hazardous Waste Incinerators", Final Report, September 21,1990.
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 CO limits. Unfortunately, the analyses could not be conducted because the facilities we
 evaluated were operating under specific CO limits and their CO levels never exceeded those
 limits when burning hazardous waste. We found that the facilities learned to comply with
 the CO limits they had to meet

       Moreover, we believe that the 100 ppmv CO limit is reasonable for a number of
 reasons.  Not only is it within the range of CO levels that are indicative of good combustion
 conditions, but the Agency believes that it is not too low because: (1) it is higher than the
 technology-based 50 ppmv CO level EPA requires for boilers burning waste PCBs (see 40
 CFR  Part 761); (2) it is higher than the CO  limits included in many hazardous waste
 incinerator permits20; (3) the Agency explicitly encourages the use of pre-alanns to
 minimize the frequency of automatic waste feed cutoffs21; and (4) the limit is implemented
 on an hourly rolling average basis which allows and minimizes the effects of short-term CO
 spikes.

       We also note that the Agency may soon promulgate regulations for municipal waste
 combustors (MWCs) that, among other controls, may limit CO concentrations to 50,100,
 or 150 ppmv (as proposed), depending on the type of MWC, over a four hour rolling
 average and dry-corrected to 7% oxygen. The MWC limits are technology-based - they
 represent levels readily achievable by well-designed and well-operated units. EPA does  not
 believe that the MWC limits present a conflict with the 100 ppmv (with provisions for an
 alternative higher limit if HC concentrations are less than 20 ppmv) limit for BIFs under
 today's rule. The Agency is confident that the BIF rule is protective because the Agency
 has determined that, when CO levels are less than  100 ppmv, PIC emissions do not pose
 significant risk. Thus, although the 100 ppmv limit is not a best demonstrated technology-
 based limit (many BIFs (and hazardous waste incinerators) readily operate at CO levels
 well below 100 ppmv), the 100 ppmv CO limit will ensure protection of human health and
 the environment

       As stated above, the CO limits are based on a flue gas oxygen content of 7 percent
 One commenter indicated that EPA's reasoning for using the CO correction of 7 percent
20     We note that the Agency proposed on April 27,1990 to apply to hazardous waste
incinerators the same CO/HC limits that today's rule applies to BIFs.
21     If the CO limit is "too low" for a given facility's design and operating conditions,
then frequent waste feed cutoffs may occur. Frequent waste feed cutoffs may actually
increase PIC emissions because the resulting perturbation to the combustion system may
upset the temperature, oxygen, fuel relationships needed for complete combustion.
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oxygen is not clear.  The commenter believes the 7 percent correction factor is unfair for
thermal units which, under normal conditions, need to operate at oxygen levels greater than
7 percent, yet operate with low levels of CO and HCs.  EPA believes that correcting CO
levels for flue gas oxygen content is necessary because without this correction, high CO
flue gas concentrations could be diluted by high rates of excess oxygen.  In today's rule,
EPA is requiring that CO be corrected to a flue gas oxygen content of 7 percent because the
majority of boilers and industrial furnaces achieve high combustion efficiency at optimum
flue gas oxygen levels ranging from 3 percent to 10 percent The optimum oxygen level to
achieve high combustion efficiency for a given device will vary depending on factors such
as fuel mix and boiler load.  In general, large combustion devices (in terms of heat input
capacity) have  optimum oxygen requirements on the low end of the range of oxygen
content, while smaller units require higher oxygen levels. EPA believes that a correction
level of 7 percent is reasonable  since this oxygen level is in the middle of the range of
typical operation for all devices and since the majority of devices burning hazardous waste
fuels have moderate heat input capacities (e.g., 20-150 MM Btu/hr).  In addition, 7 percent
oxygen is the reference level for the existing paniculate standard for hazardous waste
incinerators under 40 CFR 264.343(c).

       Moreover, the oxygen level to which CO values are corrected is not significant
since the CO levels for all facilities are corrected to a common basis.  If the oxygen
correction level  were changed from 7% to some other value, then theoretically, the CO limit
would have to be adjusted accordingly, and the effect on individual facilities would remain
the same.

       b. Implementation of the 100 ppmv CO Limit The procedures used to implement
the 100 ppmv CO limit are discussed below, including oxygen and moisture correction,
format of the limit, and compliance with the limit

       Oxygen  and Moisture Correction. The CO limit under Tier I (and Tier n) is on a
dry gas basis corrected to 7 percent oxygen. The oxygen correction normalizes the CO data
to a common base, accounting for  the variation in design and operation of the various
combustion devices. In-system leakage, facility size, and waste feed type are other factors
that cause oxygen concentrations to vary widely in flue gases and were considered in
selection of the oxygen correction factor.  The correction for moisture normalizes the CO
data that results from the different types of CO monitors used at facilities (e.g., extractive,
in situ, etc.). EPA's evaluation indicates that application of the oxygen and moisture
corrections can  change measured CO levels by a factor of two in some cases.
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       Measured CO levels must be corrected continuously for the amount of oxygen in
the stack gas according to the formula:
where COC is the corrected concentration of CO in the stack gas, COm is the measured CO
concentration according to guidelines specified in Appendix 2.1 provided in Methods
MflflMfl] for Compliance with the BIF BegyJatinnS (Methods Manual)^, E is the percentage
of oxygen contained in the air used. for combustion, and Y is the measured oxygen
concentration on a dry basis in the stack. Oxygen must be measured at the same stack
location at which CO is measured under procedures that are also provided in Appendix 2.1
of the Methods Manual.

       Format of the CO Limit. EPA proposed that the CO limits be implemented under
either of two alternative formate, the hourly rolling average format or the time-above-a-limit
format Under this approach, applicants would select the preferred approach on a case-by-
case basts. Comments were received in support of both alternative formats.  Based on
further evaluation  of the two formats and for reasons explained below, EPA is requiring
use of the hourly rolling average format for compliance with this rule.

       Under the hourly rolling average  format, a facility must measure and record CO
levels as an hourly rolling average. This approach allows instantaneous CO peaks without
requiring a cutoff provided that at other times during the previous hour CO levels were
correspondingly below the limit This approach requires a CO monitoring system that can
continuously measure and adjust the oxygen correction factor and  compute the  hourly
rolling averages.

       Under the proposed time-above-a-limit format dual CO limits would be established
in the permit:  the first as a never-to-exceed limit and the second  as a lower limit for
cumulative exceedances of no more than a specified period of time in an hour. These limits
and the time duration of the exceedances would be established on a case-by-case basis by
equating the mass emissions (peak areas) in both the formats (time-above-a-limit and
hourly rolling average formats) so that the regulation would be equally stringent in both
cases.  The instruments needed for the time-above-a-limit format would include a CO
22     U.S. EPA, Methods Manual for Compliance with the BIF Regulations. December
1990. Available from the National Technical Information Service (NTIS), 5285 Port Royal
Road, Springfield, VA 22161, (703) 487-4600. The document number is PB 91-1
                                      53

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monitor, a recorder, and a timer that could indicate the cumulative time of exceedances in

every clock hour, at the end of which it would be recalibrated (manually or electronically).

Oxygen would not be measured continuously in this format; instead an oxygen correction

factor  would  be determined from  operating data collected during the trial burn.
Subsequently, oxygen correction factors would be determined annually or at more frequent
intervals specified in the facility permit


       EPA has re-examined the time-above-the-limit format in light of several comments

received and has decided to delete this alternative in today's final rule because:.

    1. Since a facility would not be required to measure oxygen continuously under this
      format, mere would be no assurance that a facility would be operated reasonably
      close to the oxygen level at which it operated during the trial burn.  Even with a daily
      determination of an oxygen correction factor, there would be the possibility of
      "gaming" by the facility (operating the facility at low oxygen levels during the short
      test period when the oxygen is measured, getting a favorable  correction factor
      established on that basis, and thereafter letting the facility operate at high oxygen
      levels).  Since the major advantage of this format was the cheaper cost due to the
   '   omission of the oxygen monitoring requirement, adding continuous oxygen
      monitoring to this format would remove this advantage as well; and

    2. The proposed computations for converting hourly rolling averages to this format
      would be cumbersome, inexact,  and above all, very restrictive.  To obtain a
      conservative conversion, a permit writer would have to assume that CO levels will
      remain at the established never-to-exceed limit for the full specified time in die hour,
      and at the lower established limit the rest of the time.  The CO limits obtained by
      these computations would be very restrictive. As an example, a conversion of a Tier
      I limit of 100 ppmv hourly rolling average for a facility having a single CO excursion
      of 4-minutes duration in which the peak level was 1,000 ppmv,  would result in a
      permit specifying that for the remaining 56 minutes, CO could not exceed 34 ppmv,
      a very restrictive limit For example, a CO profile of 30 ppmv for 55 minutes and 40
      ppmv for die remaining 5 minutes would result in a violation.


       Compliance with the Tier I  CO Limit.  The Agency considered a number of

alternative approaches for evaluating CO readings during trial burns to determine

compliance with the  100 ppmv limit, including:  (1) the time-weighted average (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 highest 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. EPA is requiring the use of the most

conservative of these approaches, the  highest hourly rolling average approach, for
interpreting trial burn CO emissions for compliance with the 100 ppmv Tier I limit (This

approach is conservative because trial bum CO levels are compared to the maximum CO
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 allowed under Tier I -100 pptnv.) EPA believes this conservative approach is reasonable
 since compliance with die Tier I CO limit allows applicants to avoid the Her n requirement
 of evaluating HC emissions to provide the additional assurance (or confirmation) that HC
 emissions do not exceed levels representative of good operating practice.

       3. Tier II PIC Controls: Limits on CO and HC.

       a. Need for Tier n PIC Controls.  Commenters indicated that several types of
 boilers and many cement kilns will not be able to meet the (Tier I) 100 ppmv CO limit
 proposed in May 1987 even though HC concentrations will not be high at elevated CO
 levels. For example, boilers that burn residual oil or coal typically operate with CO
 emission levels  above the Tier 1100 ppmv CO limit because of inherent fuel combustion
 characteristics, equipment design constraints, routine transient combustion-related events,
 requirements for multiple fuel flexibility,  and requirements for compliance with NOX
 emission standards established under the Clean Air Act Attempts to reduce CO emissions
 from these devices to meet the Tier I limit could prove unsuccessful.  In addition, there is a
 possibility  that thermal efficiency could  be adversely affected if these attempts are
 successful.

       Similarly, industry and trade groups for  the cement industry voiced strong
 opposition to the 100 ppmv CO limit for cement kilns. These commenters indicated that
 some cement kilns, especially modem precalciners, routinely emit CO above the Tier 1100
ppmv limit In general, commenters indicated that while the Tier I limit may be appropriate
for combustion devices in which only fuel (fossil or hazardous waste) enters the
combustion chamber, it is inappropriate for cement kilns and other product kilns in which
massive amounts of  feedstocks are processed. These feedstocks can generate large
quantities of CO emissions which are unrelated to the combustion efficiency of burning the
waste and fuel. Whereas all the CO from  boilers and some industrial furnaces is
combustion-generated, the bulk of the CO from product kilns can be the result of process
events unrelated to the combustion conditions at the burner where wastes are introduced.23.
Therefore, limiting  CO emissions from these combustion devices to the Tier 1100 ppmv
level may be difficult and may not be warranted as a means of minimizing risk from PICs.
23    For example, CO can be generated from the trace levels of organic matter contained
in die raw materials as the materials move down the kiln from the "cold" feed end to the
"hot" end where the fuel and waste is fired and the product is discharged
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      . In summary, commentcrs argued that there are specific instances and classes of
combustion devices for which the Tier I CO limit would be difficult or virtually impossible
to meet, and thus this limit is  inappropriate since EPA has not established a direct
correlation between CO emissions, PIC emissions, and health risks.

       In light of these concerns, commenters suggested that EPA establish CO limits for
specific categories of combustion devices based on CO levels achieved by units operating
under best operating practices (BOP).   The Agency considered this approach but
determined that equipment-specific CO trigger limits would be difficult to establish and
support and would  not necessarily provide adequate protection from PIC emissions.
Nonetheless, EPA believes that the CO limits should be flexible to avoid major economic
impacts on the regulated community since no direct correlation has been established
between exceeding the 100 ppmv CO limit and increasing health risks from PIC emissions.
EPA  believes, however,  that at some elevated  CO level PIC emissions would pose
significant risk. At this time, EPA is unable to identify a precise CO trigger level since the
trigger level may vary by  the type and design of the combustion device and the fuel mix
used in the device. Consequently,  EPA has established a two-tiered approach to control
PICs. Under Tier I, CO is limited to 100 ppmv or less, as discussed above.  Under Tier
n, CO levels can exceed 100 ppmv provided that the owner or operator demonstrate that
the HC concentration in the stack gas does not exceed a good operating practice-based limit
of 20 ppmv (except that the Director may establish under 266.104(f) an alternative HC
limit for furnaces that feed raw material containing organic matter and, thus, cannot meet
the 20 ppmv limit).

       Under Tier n, the CO limit for a facility is based on the levels achieved during a
successful compliance test The Agency originally proposed two alternative approaches for
establishing HC emission  limits under the Tier n  waiver  a health-based approach and a
technology-based approach. These two alternatives and EPA's rationale for selecting the
technology-based approach for the final rule are discussed below. Before moving to those
discussions, however, it may be useful to summarize the conclusions of an evaluation by
EPA's Science Advisory Board of the proposed PIC controls.
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       b.  Comments by EPA's Science Advisory Board (SAB).  We present below a
summary of SAB's conclusions24 on the scientific support for EPA's proposed PIC
controls and EPA's response:

    SAB: The Agency has not documented that PICs from hazardous waste combustion
     can cause significant health risk to human health or the environment

       - EPA Response:  While the Agency agrees that available data do not show that
        PICs are likely to pose a significant health risk, EPA's emissions testing to date
        has been able to identify and quantify only as much as 60% of the  organic
        compounds being emitted during any test During many of EPA's tests, less than
        5 to 10% of organic emissions were characterized. The Agency is concerned that
        this large fraction of uncharacterized organic emissions could be comprised of
        compounds that can pose significant health risk. Therefore, the Agency believes
        that PICs have the potential to present a hazard and should be controlled.

   * SAB: It is prudent to control PICs given the inability to show that they do not pose a
     health risk because of limitations of sampling and analytical techniques and health and
     environmental impact assessment data and methodologies.

       - EPA Response: The Agency agrees. Additional emissions testing cannot be used
        to determine if, in fact, PICs can pose significant risk because the sampling and
        analytical  techniques are not available to identify the unknown compounds.
        Moreover, even if the techniques were available, health effects data are not likely
        to be available  for the compounds so that a risk assessment could not be
        conducted.

    SAB:  The use of CO and HC to ensure high combustion efficiency seems to be a
     reasonable approach to control PIC emissions.

       - EPA Response: The Agency agrees.

    SAB:  Under  the Tier n controls when CO exceeds  100 ppmv,  HC should be
     monitored continuously.
2 4    U.S. EPA, "Report of the Products of Incomplete Combustion Subcommittee of
the Science Advisory Board", Report # EPA-SAB-EC-90-004, January 1990.

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      - EPA Response: The Agency agrees. Today's final rule requires continuous HC
        monitoring under the Tier H controls (see 266.104(c)) when CO levels exceed
        100 ppmv, and for certain industrial furnaces irrespective of CO level (see
        266.104(d) for permitted furnaces and 266.103(a)(5) for furnaces operating
        under interim status).

   * SAB: There is no scientific support for the health-based approach to establish HC
     limits on a site-specific basis based on a calculated "unit risk" value for total HC and
     stack gas monitoring of HC concentrations.

      - EPA Response: The final rule does not allow the use of the proposed health-
        based approach to control HC.  HC are controlled under the technology-based
        limit of 20 ppmv. See 266.105(c).

    SAB:  The risk assessment procedures are adequate, however, to show that the
     technology-based HC limit of 20 ppmv appears to be protective of human health.

      - EPA Response: The Agency agrees.

    SAB: The Agency should show that the proposed limits for CO and HC  do not result
     in frequent automatic waste feed cutoffs that may increase PIC emissions.

      - EPA Response: See discussion in section C.2.b.i above.

      Thus, the SAB supported the overall reasonableness of the course adopted in this
rule to control potential risks from emissions of PICs.

      c.  Health-Based Approach for HC Limits. Under the Tier II health-based
approach, the Agency proposed to allow applicants to demonstrate that PIC emissions from
combustion devices pose an acceptable risk (i.e., less than 10*5) to the maximum exposed
individual (MEI).  Under this approach, EPA proposed to require that applicants quantify
HC emissions during trial  burns and assume that all hydrocarbons are carcinogenic
compounds with a unit risk value mat would be calculated based on available data. The HC
unit risk value would be 1.0 x 10~5 m^/ug and would represent the adjusted 95th percenrile
weighted (i.e.,  by emission concentration) average unit risk of all the hydrocarbon
emission data in EPA's database  of field testing of boilers, industrial furnaces, and
incinerators burning  hazardous waste. The weighted unit risk value for HC considers
emissions data for carcinogenic PICs (e.g., chlorinated dioxins and furans, benzene,

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chloroform, and carbon tetrachloride) as well as data for PICs that are not suspected
carcinogens and are considered to be relatively nontoxic (e.g., methane, and other Cl as
well as C2 hydrocarbons).25

       The Agency proposed to implement this provision by back-calculating an acceptable
HC emission rate (and, based on stack gas flow rates, a HC concentration) from the
acceptable ambient level based on the calculated "total HC" unit risk value discussed above
and allowing an incremental cancer risk of 1 in 100,000.

       A number of commenters supported the health-based approach while several others
pointed out that the approach was seriously flawed.  EPA's Science Advisory Board
reviewed the approach as discussed above and concluded that the site-specific, health-based
approach of controlling HC was not scientifically supportable.

       Upon re-evaluation, EPA believes that basing the HC limit on a health-based
approach is not supportable and, thus, has not selected this approach for the final rule.
Given the limited data base on the types and concentrations of PICs emitted over a range of
operating conditions, we are concerned that the potency value that the proposed approach
would apply to the total mass of hydrocarbons emitted may not be appropriate. It is not
clear whether the proposed potency value may overstate or understate the risk posed by HC
emissions.  In addition, we are concerned that we do not fully understand what types of
hydrocarbon emissions are actually detected by the continuous monitoring equipment For
example, as we discussed at proposal, certain halogenated compounds are under reported
by the HC detection system. Finally, as we noted at proposal, the proposed risk-based
approach could allow extremely high HC concentrations - concentrations clearly indicative
of combustion upset conditions.

       d. Technology-Based Approach: 20 ppmv HC Limit Under the technology-based
approach, the Tier I CO limit of 100 ppmv will not have to be met if HC levels in the stack
gas do not exceed a good operating practice-based limit of 20 ppmv26 (measured on an
hourly rolling average basis, reported as propane, dry corrected to 7% oxygen). As noted
25     Additional information on the development of the unit risk factor can be found in
U.S. EPA, Background Information Document for the Development of Regulations for
 ][C^ ^missions from HflT^^dous Waste Incinerators. October 1989.
and poor combustion conditions based on HC emissions data from 24 facilities. The'.
ppmv limit is not based on best operating practice. A feea operating practice limit would be
set a level on the order of 5 ppmv.

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above, EPA developed this technology-based approach because of current scientific
concerns (seconded by the SAB) related to a health-based approach. In addition, the
health-based approach could allow HC levels of several hundred ppmv, levels that are
clearly indicative of "upset" combustion conditions. The approach, as noted above, lacks a
                                                     
firm scientific basis and could allow facilities to operate under upset conditions. EPA
would not authorize such operations unless reasonably certain they would not pose a
significant risk to human health and the environment Such reasonable certainty does not
exist here.

       One commenter agreed that the PIC standard should be protective without imposing
a technology "fix." Although EPA believes the development of a health-based approach is
a step in the right direction, the Agency is concerned about whether the health-based Tier n
approach is adequately protective given the limited database on PIC emissions and the
uncertainty as to what fraction of organic emissions would be detected by the HC
monitoring system. Despite the limitations of the HC health risk assessment methodology,
EPA believes (and the SAB concurs) it is reasonable to use this methodology to predict
whether a technology-based limit appears to be protective. Accordingly, EPA used the
health risk assessment methodology to show that a 20 ppmv HC limit would not result in
an incremental lifetime cancer risk to the hypothetical maximum exposed individual greater
than 1 in 100,000..

       The final rule establishes limits for both CO and HC under the Tier n PIC controls.
The CO limit is established as the average over all runs of the highest hourly rolling average
for each run of the compliance test or trial burn. To demonstrate compliance with the HC
limit, the highest hourly rolling average HC level during the compliance test or trial bum
cannot exceed 20 ppmv (except as otherwise provided for furnaces feeding raw materials
containing organic matter), reported as propane, corrected to 7% oxygen on a dry basis.

       The Agency considered whether to establish provision for a case-by-case waiver of
tiie 20 ppmv HC limit based either on health-risk assessment or technical feasibility (i.e.,
feasibility of providing combustion conditions to minimize fuel-generated HC). The final
rule does not provide for a waiver of the  20 ppmv HC  limit as an indicator of good
combustion conditions and iimn*m fuel-generated PIC emissions. (The final rule does,
however, allow the Director to establish under the Part B permit proceedings an alternative
HC limit for industrial furnaces (e.g., cement kilns, light-weight aggregate kilns) to
account for hydrocarbons that are emitted from trace levels of organic matter in the raw
material. Any alternative HC limit established for a furnace will ensure that fuel-generated
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hydrocarbons (hazardous waste and other fuels) are less than 20 ppmv by establishing the
HC limit based on HC concentrations when the system is designed and operated under
good combustion conditions without burning hazardous waste.27 See section H.B.5 of
Part Three of this preamble for more discussion of the alternative HC limit for industrial
furnaces.)

       EPA did not provide a waiver of the HC limit in the final rule because:  (1) the
Agency believes, and SAB concurs, that a site-specific, health risk assessment approach to
establishing HC limits  (e.g., a waiver of the 20 ppmv limit) is not scientifically
supportable; and (2) a technology-based waiver is not supportable because well-designed
and operated hazardous waste combustion devices can readily meet a 20 ppmv HC limit

       Several commenters disagreed with EPA that both CO and HC should  be
monitored, stating that it is unnecessary to monitor CO if HC is monitored. The Agency
continues to believe that it is reasonable to require both CO and HC monitoring when CO
levels exceed 100 ppmv. When CO levels exceed the Tier I level, the facility is not
operating at high combustion efficiency and the potential for high PIC emissions exists.
The Agency believes that,  since CO monitoring is a widely practiced approach for
improving and monitoring combustion efficiency, and since CO emission levels may
respond more quickly to process upsets than HC levels,  the apparent redundancy in
requiring both CO and HC monitoring  is warranted to ensure protection of human health.

       Another commenter added that HC monitoring could be supplemented by frequent
testing  for common  PICs that respond poorly to HC monitors, such as  carbon
tetrachloride, formaldehyde, perchloroethylene, and chlorobenzene. At this time, the
Agency believes mat continuous HC monitoring combined with CO monitoring is adequate
in most cases to detect when the facility is operating under combustion upset conditions
(this is another reason, however, that monitoring both CO and HC is reasonable when CO
levels exceed the level normally indicative of good combustion - 100 ppmv). We note
that, as discussed in section ILD below, the final rule requires a hot HC monitoring system
(i.e., unconditioned gas sample heated to a minimum of 150C) which ensures minimum
loss of organic compounds.  Nonetheless, the Agency is currently developing sampling
and analytical techniques to continuously monitor indicator organic compounds such as
those suggested by the commenter.
27     We note that mis approach should limit fuel-generated hydrocarbon concentrations
to well below 20 ppmv because fuel-generated hydrocarbons from a well-designed and
operated cement or light-weight aggregate kiln should not exceed 5 ppmv.

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       e. Basis for Final Rule.  EPA believes that the 20 ppmv HC limit in the final rule
for the Tier n PIC controls is representative of an HC limit that distinguishes between good
and poor combustion conditions.  (When a facility operates under poor combustion
conditions, PIC emissions can increase and may result in adverse health effects to exposed
individuals.) This HC limit is within die range of values reported in the Agency's data base
for hazardous  waste incinerators, boilers, and industrial furnaces that burn hazardous
waste, and the limit is also protective of human health based on risk assessments conducted
for 30 incinerators.  See  54 FR  43723.  Under Tier II, HC must be monitored
continuously, recorded on an hourly rolling average basis, reported as ppmv propane, and
corrected  to 7 percent oxygen on  a dry basis.   In addition, CO must be monitored
continuously, corrected to 7 percent oxygen on a dry basis, recorded on an hourly rolling
average basis, and may not exceed the  limit established during the test burn (i.e., the
average over all runs of the highest hourly rolling average for each run).

       4.  Special Requirements for Furnaces. The final rule provides several special
requirements for industrial furnaces stemming from the fact that:  (1) some industrial
furnaces, notably cement kilns, are not able to meet the 20 ppmv HC limit because trace
levels of organic matter in raw materials can emit substantial levels of hydrocarbons; and
(2) the PIC controls may not be protective for furnaces (e.g., cement kilns and mineral
wool cupolas) that feed hazardous waste at locations other than where normal fuels are
fired. These special requirements are discussed below.

       a. Alternative HC Limit EPA requested comment on whether alternative HC limits
may be appropriate for certain industrial furnaces. See 54 FR 43724 (Oct 26,1989). A
number of commenters28 requested that EPA allow cement kilns, light-weight aggregate
kilns, and lime kilns that cannot meet the 20 ppmv HC limit because of the hydrocarbons
generated by trace levels of organic materials in die normal raw materials to establish a site-
specific alternative HC limit that does not allow HC levels when burning hazardous waste
to be significantly higher than  when burning normal fuels, processing normal raw
materials, and producing normal products in a system that is designed and operated to
minimize hydrocarbon concentrations in stack gas. Nineteen commenters pointed out that
28    in addition to comments on die October 26,1989 supplement to the proposed rule,
see minutes of die EPA meetings with the Cement Kiln Recycling Coalition of April 17,
1990; May 23,1990; June 4,1990;, June 20,1990; July 19,1990; and October 10,1990.
See also minutes of the EPA meeting with Southdown, Inc. on May 11,1990, and the
letter from the Cement Kiln Recycling Coalition to Bob Holloway, EPA, dated June IS,
1990.
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baseline HC emission levels from cement kilns can be attributed to the naturally-occurring
raw materials that are used in the production of cement Use of shale as a raw material, for
example, can result in HC emissions from kerogens in the shale. Use of fly ash as a
source of iron and silica could result in increased CO emissions from partial oxidation of
free carbon in the fly ash.  Commenters claim that approximately 6 to 10 cement plants
may not be able to comply with the HC limit of 20 ppmv even though they generate
minimal HC from  sources other than raw materials (e.g., hazardous waste fuels, other
fuels, organic compounds in slurry water).  The organic compounds in normal  raw
materials   would not ordinarily be hazardous, so that their  emissions (e.g.,  through
volatilization) would not raise the types of concerns normally addressed by RCRA.29

       The Agency believes that it will be possible in some situations to develop an
approach on a case-by-case basis to effectively implement an alternative HC limit under the
principle stated above. (If the 20 ppmv HC limit were health-based, the Agency would be
more reluctant to develop an alternative to it. Given, however, that the limit is a measure of
combustion efficiency, the Agency believes it reasonable to develop an alternative means
for this class of furnaces to demonstrate combustion efficiency.)  The Agency considered a
number of approaches to establish an alternative HC level and determined in the time
available that none appeared to be workable in all situations.  The Agency is therefore
adopting a more individualized approach in the present rule that allows permit writers to
establish an alternative HC limit (i.e., a HC limit that exceeds 20 ppmv) in a facility's
operating permit, and allows permit writers to grant an extension of time to comply with the
HC limit during interim status, based on the following showings: (1) for cement kilns, the
kiln is not equipped with a by-pass duct that meets the requirements of 266.104(0(1); (2)
the applicant  demonstrates  that the facility is designed and operated to minimize
hydrocarbon emissions from fuels and raw  materials; (3) the applicant develops an
approach to effectively monitor over time changes in the operation of the facility that could
reduce baseline HC levels - for example, changes in raw materials, fuels, or operating
conditions - which  could result in  establishing  a new baseline and corresponding
adjustment of the HC limit; and (4)  the applicant demonstrates that the hydrocarbon
emissions  are not likely to pose a significant health risk See 266.104(0(2). We explain
these provisions in more detail below, along with an explanation of which provisions apply
during interim status and which are part of permit application and issuance.
29     We note, however, that nonhazardous organic constituents in feedstreams may be
partially combusted to form hazardous products of incomplete combustion.

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       Interim Status Facilities. Today's rule requires facilities operating in interim status

to comply with CO and, if required, a 20 ppmv HC limit within 18 months of the rule's

date of promulgation.  The rule provides for a case-by-case extension from these
requirements (as well as the paniculate, metals, and HC1/C12 standards) "if compliance is

not practicable for reasons beyond the control  of the owner or operator."  See

266.103(c)(7)(ii). The situation where a furnace may be unable to achieve the 20 ppmv

HC limit because of organics present at baseline conditions (i.e., when the facility is

designed and operated to minimize HC emissions from raw materials and fuels while
producing normal products under normal operating conditions and when no hazardous

waste  is burned)  may  be eligible for the extension of time provided the following

conditions are satisfied:

    1. The applicant for the extension of time must have submitted a complete Part B permit
     application. The application must include the following information pertinent to the
     question of an alternative HC limit: (a) documentation that the system is designed and
     operated to minimize HC emissions from all sources  when the baseline level is
     established and when hazardous waste is burned; (b) documentation of the baseline
     HC flue gas concentration when the facility is operated to minimize HC emissions
     and when feeding normal raw materials and normal fuels to produce normal products
     under normal operating conditions and when not burning hazardous waste; (c) a test
     protocol to confirm the baseline HC (and CO) level;  (d) a trial burn protocol to
     demonstrate that, when hazardous waste is burned, HC  (and CO) concentrations do
     not exceed the baseline level; and (e) a procedure to show if and when HC emissions
     from nonhazardous waste sources may decrease (in which case, the overall HC limit
     might be adjusted downward after a new baseline is established). See 270.22(b).
     (The substantive basis for these requirements is explained in more detail below.)

    2. During interim status, the applicant must not only conduct emissions testing when
     burning hazardous waste to certify compliance with all remaining emissions controls -
     - dioxins and f brans, PM, metals, and HC1/Q2 - but also establish and comply with
     interim limits on CO and HC presented in the Part B permit application as levels the
     applicant has determined by testing (without burning  hazardous waste) are baseline
     levels.  We note  that the Director may not have time during the review of the
     extension request (and a preliminary review of the Part B application) to confirm the
     adequacy of the interim CO and HC limits proposed by  the applicant. Moreover, to
     do so would require the types of oversight of test protocols, emissions testing, and
     review of data that will be applied under the permit process. Thus, the interim limits
     are subject to revision based on (confirmation) testing in support of the operating
     permit Nonetheless, EPA believes that establishing interim CO and HC limits and
     requiring the owner/operator to comply with them until a permit is issued (or denied)
     is reasonable  and provides a  measure of protection of human health and the
     environment.

     It should be noted that the Agency does not believe that it is possible to establish an
     alternative HC limit during interim status. This is because the level of interaction
     between an applicant and permit writer over evaluation of the various protocols to
     establish a HC baseline and determine when it should be reduced, plus conducting
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     test burns to confirm the HC baseline and that HC levels do not increase when
     hazardous waste is burned, plus conducting a health-risk assessment for organic
     emissions when hazardous waste is burned are beyond the scope of interim status.
     Consequently, the rule is structured so that the alternative HC limit (if warranted)
     would be established as part of the permit, and the interim status certification of
     compliance deadline can be extended, if the Director finds this is warranted, while the
     permit is being processed.  The Director may also may make the extension of time
     conditional on the time estimated to process the permit application or other factors,
     and can be conditioned on operating conditions than ensure the facility will operate in
     a manner that protects human health and the environment Any such condition would
     be embodied in an interim status extension determination that is enforceable as a
     requirement of subtitle C (much as conditions in a closure plan are enforceable), and
     would be documented in an administrative record for the determination.

    3. Cement kilns with a by-pass duct are ineligible for an extension. The rule precludes
     cement kilns operating with a by-pass duct from eligibility for the extension of the
     certification of compliance date for compliance with the CO and HC limit, as well as
     for obtaining an alternative HC limit in a permit


       Fully Permitted Facilities.  The Director may establish an alternative HC limit in the

facility's operating permit provided that the applicant meets the following requirements.

Information and data documenting compliance with these requirements must be included in

the Part B permit application.  See 270.22(b). First, the applicant must document in the

permit application mat facility is designed and operated to minimize HC emissions from all

sources, including raw materials and fuels. Examples of situations where the system is npj

designed and operated to minimize HC (and CO) levels during baseline testing are when:
(1) coal is mixed with raw material which is fed into a cement kiln preheater such that the

coal can contribute to HC emissions; (2) cement kiln slurry water contains enough organic

compounds to significantly contribute to HC emissions; (3) waste fuels such as  tires are
burned in a manner that could contribute to HC emissions; (4) the furnace is not operated

and designed to minimise emissions of hydrocarbons emitted from raw material (in general,

the more quickly the raw material is exposed to elevated  temperatures, the lower the

hydrocarbon emissions); and (5) normal fuels are not burned under good combustion
conditions.


       Second, the applicant must propose in the permit application baseline flue gas CO
and HC levels. These proposed baseline levels also serve as interim values under which
the facility must operate under a conditional time extension for certification of compliance

with the HC standard until permit issuance (or denial).  The proposed baseline levels must
be supported by emissions testing under baseline conditions (i.e., when the facility is

designed and operated to minimize HC emissions from raw materials and fuels while

producing normal products under normal operating conditions and when no hazardous
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waste is burned). Baseline levels must be determined from test data as die average over all
valid runs of the highest hourly rolling average value for each run.  This is the same
approach specified by the rule to determine limits on other operating parameters (e.g.,
         feed rale limits, mwnup" temperatures, etc). EPA believes that this approach is
workable for cement kilns30 given that commenters have asserted that when hazardous
waste is burned, hydrocarbon levels do not increase and often decrease. As discussed in
section HE of Part Three of die preamble, HC levels from a cement kiln with HC levels of
66 to 70 ppmv when burning coal decreased to 38 to 63 ppmv when burning hazardous
waste fuel. If the facility cannot install continuous monitors for HC (and CO and oxygen)
in time to conduct these baseline tests prior to submittal of the permit application (which
must be sufficiently prior to 18 months after promulgation of the rule to give the Director
time to consider  whether to grant the time extension), the facility may use portable
monitors.  We note that the HC monitoring system must be a hot, unconditioned system.
In addition, we note that different baseline values may be necessary for different modes of
operation if the baseline HC (or CO) level changes significantly under those modes of
operation. Examples are when the raw material mix is changed to make a different cement
product or when different fuels are burned.

       Third, the  applicant must develop emissions testing protocols to: (1) confirm the
baseline HC and CO levels proposed in the permit application (and under which the facility
must operate in interim status upon receipt of an extension of time to comply with the HC
limit and until an operating permit is issued (or denied)); and (2) to demonstrate that, when
hazardous waste is burned, HC and CO levels do not exceed baseline levels (and emissions
of other pollutants do not exceed allowable levels).  If a baseline HC or CO level is to be
established for more man one mode of operation, a baseline confirmation test (comprised of
at least three valid runs) must be run for each mode.

       Fourth, the applicant must develop an approach to effectively monitor over time
changes in the operation of the facility that could significantly reduce baseline HC or CO
levels. If baseline levels are significantly reduced, then the alternative HC and CO limits
that apply when burning hazardous waste must also be reduced. Such changes could
include: (1) changes in the concentration of organic matter in raw materials;  (2) changes in
the concentration of organic matter in the raw material mix due to changes in the mixture of
30    Although any industrial furnace that cannot meet the 20 ppmv HC limit because of
organic matter in raw material is eligible to apply for an alternative HC limit, only one
commenter expressed concern that industrial furnaces other man cement kilns may not be
able to meet the 20 ppmv HC limit
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raw materials needed to produce different types of product; (3) changes in fuels; and (4)
changes in the concentration of organic compounds in slurry water used for a wet cement
kiln. The approach must be workable and enforceable.

       EPA is requiring mis condition in order to avoid establishing a high baseline which
is then reduced without also lowering the HC limit, potentially allowing the hazardous
waste to be burned under poor combustion conditions creating high, but undetected, HC
levels (i.e., hazardous waste could be burned under poor combustion conditions and could
be emitting high HC levels even though the HC limit was not exceeded). (The Agency
notes that the problem of establishing a HC baseline and for determining when the baseline
might change for this type of industrial furnace is more difficult than determining when the
raw material baseline changes in documenting when co-combustion of hazardous waste
with raw materials in a Bevill device might affect the composition of residues. See section
Xm of Part Three of the preamble. This is because, in the case of the HC baseline, not
only must the raw materials' and fuels' composition be monitored, but the units design and
operating conditions as well to determine whether the baseline has changed. Thus, the rule
provides for more interaction in establishing baseline conditions and determining when they
change for  assessing alternative HC limits for cement kilns than it does when making
determinations as to whether co-combustion of hazardous waste can remove residues from
eligibility for exclusion under the Bevill amendment)

       Finally, EPA is concerned that hazardous waste burning may affect  the type and
concentration of organic compounds emitted from an industrial furnace that has elevated
HC concentrations attributable to raw materials. For example, the chlorine in the hazardous
waste may result in higher concentrations of chlorinated organic compounds. Therefore,
the rule requires the owner or operator, as part of the permitting process, to use state-of-
the-art emissions testing procedures and risk assessment to demonstrate  that organic
emissions are not likely to pose unacceptable health risk. The owner or operator must
conduct emissions testing during the trial burn to identify and quantify the organic
compounds listed in Appendix Vm, Pan 261, that may be emitted using test procedures
specified by the Director on a case-by-case basis. As noted above, although EPA does not
believe such risk-based approaches to be adequate as the basis for a national risk-based PIC
standard, we think the approach is part of the best  means of assuring that cement kilns
combust hazardous waste fuels properly in those instances where HC levels are greater
than 20 ppmv as a result of organics in normal raw material feed.
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      Two sampling and analysis approaches that the Director may use are discussed
below. One protocol involves the following steps to identify and quantity concentrations of

organic compounds hi stack emissions:

   1. Sample volatile organic compounds using the YOST train of Method 0030 as
      prescribed in SW-846  Analytical work is conducted using GC/MS according to
      Method 5040 in SW-846.

   2. Sample semi-volatile organic compounds using the sampling train prescribed in
      Method 0010 in SW-846. Analytical work is conducted using GC/MS according to
      Method 8270 in SW-846.

   3. Sample aldehydes and ketones using an impinger train with 2-4 di-nitro-phenyl
      hydrazine (2-4 DNPH) in the impinger solution as prescribed in Method 0011 in the
      Methods Manual, and analysis of impinger solution by high performance liquid
      chromatography (HPLQ as specified in "Analysis for Aldehydes and Ketones by
      High Performance Liquid Chromatography" in the Methods Manual.

      Another protocol is a screening approach that has been described in the literature31
that uses the following protocols as specified in SW-846:

   1. Soxhlet extraction sample preparation;

   2. Gas chromatography (GQ coupled with flame ionization detector (FID) or mass
       spectrography (MS) screening;

   3. Total chromatographic organics (TCO) and gravimetric (GRAY) procedures; and

   4. High performance liquid chromatography-ultraviolet/MS (HPLC-UV/MS) screening
      and compound identification.

      To select an appropriate protocol, the Director will consider the state-of-the-art of
sampling  and analytical techniques and the expected nature of organic emissions

considering emissions data or other information.

      We note that, under this PIC risk assessment, emission rates must also be
determined for  the 2,3,7,8-chlorinated tetra-octa congeners of chlorinated dibenzo-p-
dioxins and dibenzofurans (CDDs/CDFs) using Method 23, "Determination of
Polychorinated  Dibenzo-p-Dioxins and Polychlorinated Dibenzofurans (PCDFs) from
Stationary Sources" in Methods Manual for Compliance with the BIF Regulations
31     Johnson, Larry, et al., "Screening Approach for Principal Organic Hazardous
Constituents and Products of Incomplete Combustion", JAPCA Journal, Volume 39, No.
5, May 1989.
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 (Methods Manual^ (incorporated by reference in 261.11). The risks from these congeners
 must be estimated using the 2,3,7,8-TCDD toxicity equivalence factor prescribed in
 "Procedures for Estimating the Toxicity Equivalence of Chlorinated Dibenzo-p-Dioxin and
 Dibenzofuran Congeners" in (Methods Manual,

       The owner or operator must then conduct dispersion modeling to predict the
 maximum annual average ground level concentration of each such organic compound. On-
 site ground level concentrations must be considered if a person resides on-site; otherwise,
 only off-site concentrations may be considered. Dispersion modeling must be conducted in
 conformance with EPA's Guideline on Air Quality Models. EPA's "Hazardous Waste
 Combustion Air Quality Screening Procedure" provided in Methods Manual, or EPA's
 Screening Procedures for Estimating Air Quality Impact of Stationary Sources.  All three
 documents are incorporated by reference in 260.11.

       Stack heights exceeding good engineering practice (GEP, as defined in 40 CFR
 51.100(u)) may not be used to predict ground level concentrations. See section V.B.l.c of
 Pan Three of this preamble.

       If the owner or operator applies for an alternative hydrocarbon limit for more than
 one industrial furnace such that emissions from the furnaces are from more than one stack,
 emissions testing  must be conducted on all such stacks and dispersion modeling must
 consider emissions from all such stacks.

       To demonstrate that the noncarcinogenic organic compounds listed in Appendix IV
 of the rule do not  pose an unacceptable health risk, the  predicted  ground level
 concentrations cannot exceed the levels established in that Appendix.

       To demonstrate that the carcinogenic organic compounds listed in Appendix V of
 the rule do not pose  an unacceptable health risk, the sum of the ratios of the predicted
 ground level concentrations to the levels established in the Appendix cannot exceed 1.0.
This is because the acceptable ambient levels established in Appendix V are based on a 10~5
risk level. To ensure that the summed risk from all carcinogenic compounds does not
exceed 10'5 (i.e.,  1 in 100,000) the sum of the ratios described above must be used. (We
note that the 2,3,7,8-TCDD toxicity equivalency factor is to be used to estimate the risk
from 2,3,7,8-chlorinated CDDs/CDFs, and the risk from these congeners must be added to
 the risk from other PICs to ensure mat the summed risk does not exceed 1 in 100,000.)
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       To demonstrate that other compounds for which the Agency does not have adequate
health effects data to establish an acceptable ambient level are not likely to pose a health
risk, the predicted ambient level cannot exceed 0.09 ug/m3. This is the 5th percentile
lowest reference air concentration for the compounds listed in Appendix IV of the rule.

       b.  Feeding Waste at Locations other than the Hot End. If hazardous waste is fed
into an industrial furnace at locations other than the "hot" end where the product is normally
discharged and where fuels are normally fired, the rule requires the owner/operator to
monitor HC irrespective of whether CO levels do not exceed the Tier I limit of 100 ppmv
and to comply with special restrictions during interim status.  These  provisions are
discussed below.

       Mandatory HC Monitoring*2. Except as indicated below, facilities that fire
hazardous waste into an industrial furnace at locations other than the "hot" end where the
product is normally discharged and where fuels are normally fired must comply with the
HC limit even if CO levels do not exceed the Tier I limit of 100 ppmv.  See 266.105(d).
This is because the Agency is concerned that the hazardous waste could conceivably be
fired at a location in a manner such that nonmetal compounds in the waste may be merely
evaporated or thermally cracked to form pyrolysis by-products rather than completely
combusted.  If so, little CO may be generated by the process and, thus, monitoring CO
alone would not ensure that HC emissions were minimized.

       However, if hazardous waste is burned (or processed) solely as an ingredient, HC
monitoring is not automatically required because emissions of nonmetal compounds are not
of concern. This is because the metals emissions controls will ensure that metals emissions
do not pose a hazard. (The rule establishes the restrictions discussed below because we are
concerned that the interim status controls on organic emissions may not be protective when
hazardous waste is fed at locations other than the "hot" end of a furnace.)  See discussion
in section VD.H of Part Three of this preamble for when a waste is considered to be burned
solely as an ingredient33.
32    Continuous HC monitoring is required for a furnace if hazardous waste is fired at
any location other man the "hot", product discharge end where fuels are normally fired
irrespective of the CO level in stack emissions (i.e., irrespective if CO levels are lower than
the Tier I limit of 100 ppmv) and irrespective of whether furnace off-gas is passed through
another combustion chamber.
33    Regulated entities have indicated that there is substantial confusion over the terms
"use as an ingredient" and "material recovery". Under the RCRA hazardous waste
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       Interim Status Restrictions.  In addition to requiring HC monitoring when
hazardous waste is fed into a furnace at locations other than the "hot" end where the
product is discharged and where fuels  are normally fired, today's rule applies other
restrictions to hazardous waste burning during interim status.  See 266.104(a)(5).  The
hazardous waste may not be fed at any location where combustion gas temperatures are less
than 1800F, and the owner or operator must demonstrate that adequate oxygen is present
to combust the waste.  In addition, for cement kilns, the hazardous waste must be fed into
the kiln itself. These requirements are provided to ensure adequate destruction of the waste
given that the DRE standard (which requires a demonstration by trial burn that organic
constituents in the waste are destroyed) is not applicable during interim status.  Like the
requirement for mandatory HC monitoring, however, these restrictions do not apply if the
hazardous waste is burned (processed) solely as an ingredient. For further discussion, see
section VH Ji of Pan Three of this preamble.

       5. Special Considerations for Cement Kilns.

       a. Monitoring in the By-Pass Duct of a Cement Kilns. The final rule provides that
cement kilns with by-pass ducts may monitor CO and, if required,  HC concentrations in
the by-pass duct  Most precalciner and some preheater kilns are equipped with by-pass
ducts where a portion (e.g., 5-30%) of the  kiln off-gas is diverted to a separate air pollution
control system (APCS) and, sometimes, a separate stack.  A portion of the kiln gases are
so diverted to avoid a build-up of metal salts that can adversely affect the calcination
process. Dust collected from the by-pass APCS is usually disposed of while dust collected
from die main APCS is usually recycled back into the kiln to make the clinker product

       Several comments were received regarding sampling at cement kilns.   Five
commenters suggested that HC (and CO) measurements should be allowed in the bypass
duct rather man in the main stack because: (1) the by-pass gas is representative of the kiln
off-gas; and (2) this approach would preclude the problem of nonfuel HC emissions from
the raw material exceeding the 20 ppmv limit The raw material would be heated and
partially calcined in the precalciner or preheater and HC from that process would be emitted
regulatory program, EPA considers a hazardous waste to be burned or processed as an
ingredient tf it is used to produce a product EPA considers a hazardous waste to be
burned or processed for material recovery if one or more constituents of the waste is
recovered as a product
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from the main stack. The by-pass duct draws the kiln off-gas prior to the precalciner or
preheater and, so, would not be affected by that process.

       Another commenter specifically supported monitoring CO (and HC, if required)
only in the bypass duct provided that hazardous waste is fed only to the kiln and not to the
preheater or precalcii
       The Agency conducted testing34 at a cement kiln to gather information relevant to
the issue of HC monitoring in the bypass duct for preheater and precalciner cement kilns.
The data showed that the gases in the bypass duct are representative of the combustion of
waste in the kiln.

       Based on this test data and public comment, the final rule allows CO and, where
required, HC monitoring in the by-pass duct of a cement kiln provided that:  (1) hazardous
waste is fired only into the kiln (i.e.,  not at any location downstream from the kiln exit
relative to the direction of gas flow); and (2) the by-pass duct diverts a minimum of 10% of
kiln off-gas. See 266.104(0(1). The 10% diversion requirement is based on engineering
judgment that, at this level of kiln-gas diversion, the by-pass gas will be representative of
the kiln off-gas. Industry representatives indicate35 that the by-pass duct capacity of most
facilities actively involved in burning hazardous waste exceeds the 10% limit

       b.  Use of Hazardous Waste as Slurry Water for Wet Cement Kilns. Some kiln
operators have inquired as  to what regulatory standards apply, if any, if hazardous wastes
are used as slurry water. The Agency does not regard die practice as an excluded form of
recycling.  The Agency has  long been skeptical of claims that hazardous wastes are
"recycled" when they substitute for very commonly available and economically marginal
types of raw materials. In particular, the Agency has been skeptical that liquid hazardous
wastes serve as a substitute for water. Cf. 48 FR at 14489 (April 4,1983).  In the case of
hazardous waste used as slurry water, the hazardous constituents in the waste are ordinarily
unnecessary to the claimed recycling activity and  are being gotten rid of through the
slurrying process.  Given the possibility of hazardous levels of air emission is high, die
practice certainly can be part of the waste disposal problem. Consequently, the Agency
34    U.S.EPA, "Emissions Testing of a Precalciner Cement Kiln at Louisville,
Nebraska", November 1990.
       Letter dated August 16,1990, from Dr. Michael von Seebach, Southdown, Inc., to
35
Dwight Hlustick, EPA.
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 regards such practice as a form of waste management subject to regulation under today's
 rule.

       EPA considered prohibiting the use of hazardous waste as slurry water for wet
 cement kilns because of concern that toxic organic constituents in the waste could be
 volatilized and emitted without complete combustion. The final rule does not prohibit using
 (or mixing) hazardous waste with slurry water because we believe that the controls
 provided by the rule both during interim status and under a RCRA operating permit
 adequately addresses the hazard mat the practice may pose.

       If hazardous waste is fed into any industrial furnace during interim status at a
 location other than the hot, product discharge end, combustion gas temperatures must
 exceed 1800F at the point of introduction, and the owner or operator must document that
 adequate oxygen is present to combust organic constituents in the waste.  See discussion
 above.  EPA believes that these restrictions will, as a practical matter, preclude use of
 hazardous waste in slurry water during interim status.

       Although these restrictions on hazardous waste burned at locations other than the
 hot end of an industrial furnace do not apply under a RCRA operating permit, the permit
 proceedings will ensure that organic constituents in a hazardous waste that is fed into the
 kiln in slurry water (or in the slurry itself) will be destroyed. The Director will require that,
 toxic nonmetal constituents in the waste are destroyed to a 99.99% destruction and removal
 efficiency, and that adequate oxygen is present to completely destroy the organic
 compounds.

 C. Automatic Waste Feed Cutoff Requirements.

       Today's rule requires that boilers and industrial furnaces combusting hazardous
 waste be equipped with automatic waste feed cutoff systems to limit emissions of
 hazardous compounds during combustion "upset" situations and to  ensure stable
 combustion conditions. The automatic waste feed cutoff system must be connected to the
CO and HC monitoring system, such that an exceedance of a CO or HC limit would trigger
 a cutoff of the waste feed.  Additionally, the automatic waste feed cutoff system must
engage when other key operating conditions deviate from specified unit operating limits,
which are determined during compliance testing or which are based on manufacturer
specifications. See 266.102(e)(7)(ii) and 266.103(h).
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       Some commenters disagreed with the proposed automatic waste feed cutoff
requirements,  (tee commenter argued against any waste feed cutoffs for light-weight
aggregate kilns. Six commenters expressed concern that waste feed cutoffs would increase
the instability of the combustion conditions and would possibly increase air emissions.
Three commenters requested a controlled waste feed reduction over several minutes rather
than an automatic waste feed shutoff. Three commenters suggested different levels of CD
emissions be set for waste feed cutoffs.

       The Agency  acknowledges that there can be performance and other problems
associated with automatic waste feed cutoffs, and recognizes that they may be undesirable
for some applications. For example, when the facility operates without the use of
hazardous waste fuel, use of fossil fuel is increased, and the opportunity is lost for safe
disposal of hazardous waste. Further, HC emissions may actually increase if the automatic
waste feed cutoff is triggered frequently even though combustion chamber temperatures
must be maintained while hazardous waste or residues remain in the combustion chamber.
However, the Agency continues to believe that automatic waste feed cutoff systems are
necessary to avoid adverse effect on human health and the environment that could result if
hazardous waste is fired into the device when it is operating under combustion upset
conditions.                                                              

       To address the concerns raised by commenters, EPA recommends installing pre-
alann systems that alert an owner/operator of potential problems and provide time either for
corrective measures to be taken or for a staged cutoff of the hazardous waste feed. Thus,
the use of pre-alarms should minimiye waste feed cutoffs. In addition, we have included in
the rule some additional requirements related to waste feed cutoffs and restarts, as
discussed below.

       One commenter stated that cutoffs are inappropriate for combustion devices where
the waste is destroyed immediately upon injection into the combustion chamber  (e.g.,
devices that burn liquid wastes), or if the combustion conditions supported by the waste
fuel continue to destroy residual waste after waste feed cutoff.  The Agency continues to
believe that the best method for returning a combustion system to good operating
conditions, thereby minimizing unacceptable emissions, is to stop the input of hazardous
waste.  Further, the burden associated with automatic cutoffs should not be substantial
because frequent automatic waste feed cutoffs should not occur given that the parameters
tied into the automatic cutoff system may be monitored on a hourly rolling average basis
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(which allows high values to be off-set by low values) and that the Agency recommends
the use of pie-alarms to warn the operator of a pending cutoff (which may give the operator
time to take collective measures to avoid an automatic cutoff).

       In the event of a waste feed cutoff, monitoring for CO and HC (and other operating
parameters for which limits in the permit are based on a rolling  average basis) must
continue, and the waste feed cannot be restarted until CO and HC levels (and levels of the
other parameters) come within allowable limits.  See 266.102(e)(7)(ii). (For permit
operating conditions not established on a rolling average basis, the Director will specify, on
a case-by-case basis, an adequate period of time during which the parameters must remain
within permit limits to demonstrate steady-state operation prior to restarting the hazardous
waste feed.)  In addition, consistent with the April 27, 1990 incinerator amendments
proposal, the provision of the final boiler and industrial furnace rule requiring compliance
with the permit operating conditions states  that compliance must be maintained at any time
there is waste in the unit  See 266.102(e)(l). This language clarifies that activation of the
automatic waste feed cutoff does not relieve the facility of its obligation to comply with the
permit conditions if there is waste remaining in the unit (such as in a rotary kiln). Thus, for
example, the air pollution control system must continue to be operated within the applicable
permit conditions.

       Furthermore, after a cutoff, the temperature in the combustion  chamber must be
maintained at levels demonstrated during the compliance test for as long as the hazardous
waste or residue remains in the combustion  chamber.  The Agency believes  this
temperature requirement will help ensure  that hydrocarbon emissions will be minimized
after a cutoff.

      To comply with this requirement, the operating permit must specify the minimum
combustion chamber temperature after a waste  feed cutoff while waste remains in the
combustion chamber. An uninteiruptable burner using auxiliary fuel (i.e., nonhazardous
waste fuel) of adequate capacity  may be needed to maintain the temperature in the
combustion chambers) and to allow destruction of the waste materials and associated
combustion gases left in the system after the waste feed is automatically cut off. The safe
startup of the burners using auxiliary fuel requires approved burner safety management
systems for prepurge, pilot lights, and induced draft fan starts. If these safety requirements
preclude immediate startup of auxiliary fuel burners and such startup is needed to maintain
temperatures (i.e., if the combustion chamber temperatures drop precipitously after waste
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feed cutoff), the auxiliary fuel may have to be burned continuously on "low fire" during
nonupset conditions.

      Furthermore, 266.102(e)(7)(ii)(B) requires that the combustion gases must
continue to be routed through the air pollution control system as long as waste remains in
the unit One effect of this clarifying requirement, in combination with the requirement to
maintain compliance with permit conditions as long as there is waste in the unit, is that
opening of any type of air pollution control system bypass stack while there is waste in the
boiler or furnace would be a violation of the permit (unless the facility demonstrates
compliance with the performance standards during the trial bum, with the vent stack open).

      Although we believe that such emergency bypass stacks are not prevalent on boilers
and industrial furnaces, our discussion of this topic in the preamble to the incinerator
amendments at 55 FR 17890 (April 27,1990) would also apply to any boiler or industrial
furnace with such a bypass or vent stack.  We received a number of comments from the
incinerator industry expressing concern that use of a bypass stack for safety purposes
would be considered a violation. We agree that there can be mitigating circumstances to
discredit their use as a safety device. However, the Agency continues to believe that the
facility can and should implement measures to minimize situations where use of the
emergency vent stack is necessary.

      One commenter stated that the use of hazardous waste should be prohibited during
startup or shutdown periods for a cement kiln until normal operating temperatures are
achieved.  The final rule does not restrict hazardous  waste burning during kiln startup or
shutdown provided that the compliance (or trial burn) covers those periods of operations.
In other words, hazardous waste may be burned during startup and shutdown if the facility
demonstrates conformance with the standards during those operations.

      Another commenter argued that accurate measurement of combustion chamber
temperature for some combustion devices will be difficult Because of this difficulty, the
final rule does not require that this temperature be directly measured in the combustion
chamber if an owner/operator can demonstrate to permitting officials that the combustion
chamber temperature correlates with a more easily measured downstream gas temperature.

      One commenter agreed with EPA's revised proposal not to limit the number of
automatic waste feed cutoffs, but disagreed with EPA's requirement that combustion
chamber temperatures must be maintained at the levels that occurred during the trial bum
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 for the duration of time that the waste remains in the combustion chamber. This commenter
 believed that electric utility boilers and other burning devices will have difficulty in
 accurately measuring combustion chamber temperatures. For this reason, the commenter
 suggested that waste feed cutoffs alone be used to control HC emissions rather than also
 requiring that combustion chamber temperatures be maintained.  EPA believes that the
 flexibility that the final rule allows for monitoring combustion chamber temperature and in
 setting the frequency of waste feed cutoffs as discussed above should address this
 commenter's concerns.

       Another commenter supported the proposed 10 times per month limit on the number
 of automatic waste feed cutoffs and the proposed requirement that any facility exceeding
 that frequency would be required to cease burning hazardous waste, to notify the Director,
 and not to resume burning hazardous waste until reauthorized by the Director. Another
 commenter supported monthly cutoff limits because they would provide an incentive for the
 facility to take corrective measures to preclude frequent cutoffs. Some commenters stated
 that this requirement is overly restrictive.

       After careful consideration, EPA has decided to modify this requirement for the
 following reasons: (1) the Agency does not have data indicating a specific frequency of
 cutoffs which would be unacceptable at all boilers and furnaces given that the combustion
 chamber temperature and other conditions are maintained as described above; (2) the
 Agency believes that operating costs associated with cutoffs will provide sufficient
 incentive to encourage owners/operators to minimise automatic waste feed cutoff incidents;
 and (3) the recommended use of pre-alarm systems will reduce the number of waste feed
 cutoffs. However, the final rule allows the Director to use his discretion to determine
 whether a limit on die frequency of cutoffs is warranted at a specific facility.

       Waste Feed Restarts.  Today's rule provides that when the automatic waste feed
 cutoff is triggered by a CO limit or when applicable, an HC exceedance, the waste feed can
 be restarted only when the hourly rolling average CO/HC levels meet the permitted limits
 (e.g., 100 ppmv for CO under Tier I).

       The Agency proposed two alternative approaches for restarting the waste feed when
 a cutoff is triggered by a CO exceedance: (1) restart the waste feed after an arbitrary 10-
 minute time period to enable the operator to stabilize combustion conditions; or (2) restart
die waste feed after die instantaneous CO level meets the hourly rolling average limit Eight
commenters supported restarting the waste feed after the instantaneous CO level meets the
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permit limit  Five commenters suggested that waste feed can be restarted once the
instantaneous CO level meets die hourly rolling average limit The Agency considered the
comments, but continues to believe that allowing a waste feed restart after die hourly rolling
average equals or falls below die permitted limit is preferable. After die waste feed is
cutoff, the facility will be burning nonhazaidous waste (typically fossil fuel), which should
result in CO and HC levels well below die allowable limits. Therefore, .die hourly rolling
average should fall below die permitted limit within  a relatively brief period of time.
Allowing the waste feed to be restarted when die instantaneous CO level has dropped to die
permitted level may not be desirable, because restarting die waste feed immediately may
trigger another cutoff due to a CO spike when the waste feed is restarted.

       Three commenters supported die proposed approach to require  die HC hourly
rolling average to be met before restarting the waste feed cutoff because of a HC
exceedance.  Three commenters opposed this approach. Instead,  these commenters
suggested a 10-minute waiting period be used. EPA considered Uiese comments but
continues to believe that meeting die hourly rolling average is a conservative approach and
is appropriate after a HC exceedance, because die HC is a better surrogate for toxic organic
emissions than CO.

D. CEMRequirements forPIC Controls.
      t
       The final rule promulgates the  proposed performance specifications for
continuously monitoring CO, HC, and oxygen. See Methods Manual far Compliance with
the BIF Regulations, incorporated by reference in today's rule  in  260.11.  The
performance specifications for HC monitoring, however, include specifications for bodi
hot and cold monitoring. Although hot monitoring is generally required by die final rule,
cold monitoring may be used for interim status facilities if they certify compliance with die
emissions standards  widun  18 montiis of promulgation of die rule.  Even if cold
monitoring is used to certify initial compliance, however, hot monitoring is required for
these facilities when they recertify compliance and when tiiey are issued a RCRA operating
permit

       One commenter stated that an HC monitoring system is  readily  available for
continuous emissions monitoring (CEM), while five commenters maintained diat HC
analyzers have serious operational problems. Several commenters requested that alternate
HC CEM methods be allowed, specifically monitors with non-dispersive infra-red (NDIR)
detectors radier tiian die required flame ionization detector (FID).  One commenter noted
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that EPA has not validated the FID method for HC analysis nor has it provided any critical
discussion of the current methods of HC analysis.

      Hie Agency considered the use of NDIR detectors for HC monitoring but believes
that NDIR systems have limitations compared to FID systems.  EPA believes that FID
systems are more sensitive than NDIR systems and that an equivalent response is not found
with NDIR detectors. Hie final rule requires the use of FID detectors for HC monitoring.

      Four commenters recommended monitoring nonmethane hydrocarbons (NMOC) as
opposed to "total" HC because methane, which is predominantly emitted from fuel sources,
has a high FID response factor. Furthermore, these commenters would like EPA to require
testing for specific PICs that respond poorly to HC monitors during test bums.  One
commenter stated that HC monitors can be varied easily  to detect NMOC. EPA does not
agree with either suggestion. The Agency is requiring HC monitoring to indicate whether
the device is operating under good combustion conditions. We acknowledge that the
largest fraction of organic compounds that the HC monitoring system required by the final
rule  will detect for facilities operating under good combustion conditions will  be
compounds that are relatively nonhazardous (e.g., methane). In addition, some hazardous
compounds, particularly highly chlorinated compounds) will be under-reported.  Thus,
although the promulgated approach would not be adequate for the purpose of assessing the
risk that HC may pose from a given facility, the  approach is adequate for its intended
purpose - a measure of whether the facility continues to operate within good combustion
conditions.  This is because EPA's emissions testing has shown that when combustion
conditions deteriorate, the compounds that are readily detected by the promulgated HC
monitoring system increase correspondingly.

      In addition, if a NMOC system were used, the 20  ppmv HC limit would have to be
lowered to account for the methane fraction that would no longer be counted Commenters
did not provide support for so adjusting the proposed HC limit Further, the Agency is
concerned that NMOC detectors may not be able to provide continuous data due to the time
required for methane separation.  The Agency has also found that HC CEMs are more
durable than NMOC CEMs, and thus less prone to reliability problems.  As a result, the
Agency has concluded that HC CEMs are more likely to provide a continuous indication of
combustion conditions man is possible with an NMOC monitor.

      Hot Versus Cold HC Monitoring Systems.  Except as indicated below, the final
rule requires the use of a hot or unconditioned  HC monitoring system that must be
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maintained at a temperature of at least 150C until the sample gas exits the detector.  See
performance specifications in MctflftdS Msnv^ for ^rtHTlpliyMr6 ^ith the BIF Regulations
(incorporated by reference, see 260.11). Given, however, that the technology has just
recently been demonstrated36 to be continuously operational on  hazardous waste
combustion devices, the final rule allows the use of a conditioned gas monitoring system
during the initial phase of interim status operations.  Facilities in interim status that certify
compliance with the emission standards for metals, HQ, Cl2, paniculate matter, CO and
HC within 18 months of promulgation of the final rule may obtain an automatic waiver to
use a conditioned gas system.  Facilities that elect to obtain the automatic 12-month
extension (or a case-by-case extension) of the  18-month certification deadline, however,
are not eligible for the waiver because the additional time provided by  the extension will
also provide time to install an unconditioned HC monitoring system. These facilities must
demonstrate compliance with the HC limit using an unconditioned gas monitoring system.
Further, facilities that certify initial compliance using a conditioned gas (cold) system must
use an unconditioned gas (hot) system when they recertify compliance within three years of
certifying initial compliance.

       EPA is requiring the use of a hot monitoring system because it represents best
demonstrated technology given that a larger fraction of HC emissions can be detected with
a hot system.   As discussed at proposal, a hot HC monitoring system can detect a
substantially larger fraction of hydrocarbon emissions than a cold system. This is because
the cold system uses a  gas conditioning system that removes semi- and nonvolatile
hydrocarbons and a substantial fraction of water-soluble volatile hydrocarbons.

       EPA received numerous comments regarding gas conditioning (heated versus
unheated) for HC monitoring. Eight commenters are in favor of gas conditioning.  The
purpose of gas conditioning is to remove moisture from the combustion gases that can
degrade instruments  or plug sample lines. Sample conditioning, however, can also remove
some of the water soluble hydrocarbons and the semi and nonvolatile hydrocarbons in the
flue gas such that methane and other nonhazardous volatile hydrocarbons are frequently the
dominant constituents measured by the detector. Some commenters were concerned that
fewer PICs would  be detected by  a conditioned (i.e., cooled) monitoring  system.
36    Entropy Environmental Inc., "Evaluation of Heated THC Monitoring Systems for
Hazardous Waste Incinerator Emission Measurement", Draft Final Report, October 1990;
and Shamat, Nadim, et al, "Total Hydrocarbon Analyzer Study", Paper presented at the
 63rd Water Pollution Control Federation Conference in Washington, D.C., October 8,
 1990.
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 However, one commenter stated that even though the constituents contributing most of the
 hypothetical risk are relatively nonvolatile they are relatively nondetectable through an
 unconditioned (heated) monitoring system because of their halogen content

       As discussed at proposal, the Agency is using HC monitoring to implement the
 technology-based HC limit of 20 ppmv  as an indicator of good combustion conditions.
 The HC monitor is not used in an attempt to quantify organic emissions for risk assessment
 purposes. Emissions testing has shown that during combustion upset condition, both the
 hot and cold HC monitoring systems detect an increase in HC levels because under upset
 conditions there is a substantial increase in hydrocarbon compounds that are readily
 detected by either monitoring system.37

       One commenter suggested that,  rather than specifying a range of 40-64F for
 operation on the conditioner as proposed, a specific conditioning temperature (32F)
 should be required to precisely define the conditioned sampling procedure. We agree that a
 minimum temperature should be specified rather than the range. The final rule allows a
 conditioned monitoring system during the initial phase of interim status, and requires that
 the sample gas temperature must be maintained at a minimum of 40F at all times prior to
 discharge from the detector. EPA selected a minimum temperature of 40F from the range
 of 40 to 64F to ensure that moisture was effectively removed from the  gas sample to
 preclude plugging and fouling problems with the monitoring system.

       Three commenters suggested that the HC limit of 20 ppmv be re-examined because
 gas conditioning temperatures or other changes in the measurement method may influence
 the amount of HC measured.  Given that the 20 ppmv limit is based primarily on test burn
 data using heated (i.e., unconditioned) monitoring  systems, the Agency considered
 lowering the 20 ppmv limit when a cold (i.e., conditioned) monitoring system is used.
 (Limited field test data indicate that a heated system would detect from 30% to 400% more
 of the mass of organic compounds than a  conditioned system.) We believe, however, that
 the 20 ppmv HC limit is still appropriate when a conditioned system is used because: (1)
 the data correlating heated vs conditioned systems are very limited; (2) the data on HC
 emissions are limited (and there apparently is confusion in some cases as to whether the
37    EPA is requiring the use of a hot, unconditioned HC monitoring system (except
under certain circumstances during the initial phase of interim status) because hot systems
are, nonetheless, more conservative in that they detect a larger fraction of organic
compounds in emissions. Further, hot systems represent best demonstrated technology for
monitoring HC levels.              .                   .      .
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data were taken with a conditioned or unconditioned monitoring system); and (3) the
Agency's risk methodology is not sophisticated enough to demonstrate that a HC limit of 5
or 10 ppmv using a conditioned system rather than an unconditioned system is needed to
protect human health and the environment  The SAB38 also concurs with this view.
(More detailed responses to comments on this issue are found in a separate background
document.)

E. Control of Dioxin and Furan Emissions.

      For facilities that may have the potential for significant emissions of chlorinated
dibenzodioxins and dibenzofurans (ODD/CDF), the final rule requires emissions testing for
both interim status  and new facilities to determine emissions rates of all tetra-octa
congeners, calculation of a toxicity equivalency  factor, and dispersion  modeling to
demonstrate mat die predicted maximum annual average ground level concentration (i.e.,
the hypothetical maximum exposed individual) does not exceed levels that would result in
an increased lifetime cancer risk of more than 1 in 100.000.39 The Agency considers a
facility to have the potential for significant CDD/GDF emissions if it is equipped with a dry
paniculate matter control device (e.g., fabric filter or electrostatic prccipitator) with an inlet
gas temperature within the range of 450 to 750 F, or if it is an industrial furnace that has
hydrocarbon levels exceeding 20 ppmv. See 266.104(0(2).

      Dispersion modeling must be conducted in confbrmance with EPA's Guideline on
Air Quality Models (Revised), EPA's "Hazardous Waste Combustion Air Quality
Screening Procedure" provided in Methods Manual for Compliance with  the BIF
Regulations,  or  "EPA SCREEN Screening Procedure" as described in Screening
Procedures for Estimating Air Quality Impact of Stationary Sources. All three documents
are incorporated by reference in today's final rule at 260.11.  To evaluate potential cancer
risk from  the CDD/CDF congeners, prescribed procedures must be used to estimate the
2,3,7,8-TCDD toxicity equivalence of the 2,3,7,8-chlorinated congeners. See "Procedure
for Estimating Toxicity Equivalent of Chlorinated Dibenzo-p-dioxin and Dibenzofuran
 38    U.S. EPA, "Report of the Products of Incomplete Combustion Subcommittee of
 the Science Advisory Board", Report # EPA-SAB-EC-90-004, January 1990.
 39    EPA is not requiring that the estimated cancer risk from CDD/CDF be added to the
 risk from metal emissions to demonstrate that the summed risk to the maximum exposed
 individual is less than 10~5. The Agency believes that it is inappropriate to sum the
 estimated health risk from metals that are known or probable human carcinogens with a
 toxicity equivalency factor for CDD/CDF that is designed to be very conservative.

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Congeners" in Methods Mfflpu3^ ^m PftUPPliflflCC with ^e BIF Rcril8tiffnf incorporated in
the rule by reference in 260.1 l(a).

      Studies conducted  by the Agency40 and others41 during development of
regulations for municipal waste combustors (MWCs) concluded that PM control devices
operated at temperatures greater than 450F have the potential for emitting elevated levels of
CDD/CDF. At these temperatures, precursor organic materials and chlorine in the flue gas
can be catalyzed by PM captured in the PM collection device to form CDD/CDF. Based on
these findings, the Agency proposed to restrict the combustion of hazardous waste in BIFs
that operate with PM control device temperatures greater than 450F.

      A number of commenters opposed the proposed limitation on the flue gas
temperature to less than 450F. Several commenters pointed out technical distinctions
among types of boilers and industrial furnaces that affect the ability of a unit to change flue
gas temperature and the potential of an ESP to form CDD/CDF. For example, many boiler
and industrial furnaces either combust wastes that are very low in chlorine or that have high
levels of chlorine capture within the process (e.g., cement kilns). As a result, the
CDD/CDF emission potential will vary for different boilers and industrial furnaces, as well
as between boilers and industrial furnaces and MWCs. Commenters also stated that there
is no direct evidence of CDD/CDF emissions from several types of boilers and industrial
furnaces, and that compliance testing to demonstrate 99.99 percent ORE of POHCs and
continuous monitoring of CO and HC levels is adequate to ensure minimal emissions of
organic compounds.

      Hie Agency has reviewed the available data on the theory of CDD/CDF formation
as well as CDD/CDF emissions from BIFs.  Based on this review, the Agency agrees that
most,  but not necessarily all, BIFs burning hazardous waste have low CDD/CDF emission
rates.  For example, EPA recently tested a cement kiln burning hazardous waste that
operates with an ESP at a temperature of 500-550F and found it to have relatively high
CDD/CDF emissions.42 (EPA conducted a risk assessment, however, that estimated the
40    See U.S. EPA, "Municipal Waste Combustion Study: Combustion Control of
Organic Emissions", EPA/530-SW-87-021C, NT1S Order No. PB87-206090; U.S. EPA,
"Municipal Waste Combustion Study: Flue Gas Cleaning Technology", EPA/530-SW-87-
021D, NTIS Order No. PB87-208108; and 54 FR 52251 (December 20,1989).
41    Vogg R and L. Stieglitz,Thermal Behavior of PCDD/PCDF in Fly Ash from
Municipal Waste Incinerators", Chemosphere, pp. 1373-1378,1986.
4 2    u^s. EPA, Emissions Testing of a Wet Cement Kiln at Hannibal. MQ. December
1990.
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increased lifetime cancer risk to the hypothetical
                                                     exposed individual from the
CDD/CDF emissions ranged from 7 in 10,000,000 to 2 in 1,000,000 without burning
hazardous waste and from 2 in 1,000,000 to 4 in 1,000,000 when burning hazardous
waste, well under the 1 in 100,000 limit established in today's rule.) The Agency suspects
that die elevated CDD/CDF concentrations in the stack gas at mis cement kiln are the result
of the ESP's operating temperature and the level of HC precursor material in the flue gas.
HC concentrations ranged from 66 to 70 ppmv (measured with a hot system, reported as
propane, and corrected to 7% oxygen, dry basis) without hazardous waste burning and
from 38 ppmv to 63 ppmv with hazardous waste burning.  (We note that to continue
burning hazardous waste under today's rule, the Director must establish during the Part B
permit proceedings an alternative HC level for this loin based on a demonstration by the
applicant that HC levels are not higher when burning hazardous waste than under normal
conditions and that the facility is designed and operated to minimize HC  emissions from all
sources  fuels and raw materials.  At certification of compliance with the emissions
controls other than the HC limit, this facility must also propose a HC concentration limit for
the remainder of interim status (until that limit or another limit is established under permit
proceedings) that will ensure that HC levels when hazardous waste is burned will not be
higher than baseline levels (i.e., HC levels when the system is designed and operated to
minimize HC emissions from all sources, when burning normal fuels and feeding normal
raw materials to produce normal products, and when not burning hazardous waste)). In
addition, trial burn emissions  testing must demonstrate that  emissions of organic
compounds are not likely to result in an increased lifetime cancer risk to the hypothetical
maximum exposed individual exceeding 1 in 100,000.  See  266. 104{f) and discussion in
section ILB.S.b of Part Two of this preamble.) There may be other factors that influence
CDD/CDF levels at this facility (and other facilities), but this is uncertain. In addition, the
exact HC concentration in combustion gas below which elevated CDD/CDF concentrations
will not occur is unknown.

      The Agency continues to believe that the operating temperature of the PM control
device (and HC concentrations in flue gas) plays a significant role in CDD/CDF emissions.
For a given HC concentration in the flue gas, the available data suggest that the potential for
elevated CDD/CDF emissions is low if the PM control device operates  at temperatures of
less than 4SOF or above 750F. Consequently, today's rule does not  require BIFs with
PM control devices operating at temperatures outside of the 450-750F window to
determine CDD/CDF emission rates (unless it is an industrial furnace with HC levels
greater than 20 ppmv). Owners and operators of units operating within the temperature
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window, however, are required to conduct stack testing to determine CDD/CDF emission
rates and to conduct a risk assessment using prescribed procedures to demonstrate that the
estimated increased lifetime cancer risk to the hypothetical maximum exposed individual is
less than 1 in 100,000.

       The Agency notes that the final rule for municipal waste combustors (MWCs) may
take a slightly different approach to control dioxin and furans by limiting temperatures at
the inlet of the PM air pollution control system to within 30F of those achieved in  a
dioxin/furan compliance test The preamble to that rule, however, will probably continue
to note the possibility of dioxin/furan formation in the temperature range of 230C (450F).
In today's rule, the Agency believes that using temperature and HC levels as a trigger to
dioxin/furan testing and risk assessment will be fully protective of human health and the
environment and somewhat easier to implement than the MWC approach.

in.  Risk Assessment Procedures

       The Agency uses assessment of health risk to develop and implement the final rules
for metals, hydrochloric acid (HC1), and chlorine gas (Cl2)- Specifically, the Agency has
used risk assessment to:  (1)  establish ambient air concentrations of Appendix Vm
compounds that do not pose an unacceptable health risk for purposes of this rulemaking;
and (2) establish risk-based, conservative feed rate and emissions  Screening Limits for
metals and HC1.  In addition, if facilities fail the Screening Limits or elect to conduct
dispersion modeling to obtain less conservative limits, the rule allows facilities to use site-
specific dispersion modeling to establish emission limits, and ultimately feed rate limits for
metals and chlorine.

       To establish health-based acceptable ambient concentrations for noncarcinogenic
toxic metal and nonmetal compounds (except for HC1, Q2 and lead), EPA converted oral
reference doses to reference air concentrations (RACs) by assuming average breathing
volumes and body weights, and by applying a safety and a background level factor. See
54 PR at 43756. Health-based concentrations for carcinogenic pollutants were derived by
converting cancer potency factors, or slopes (unique for each carcinogen), into Risk
Specific Doses (RSDs) at a risk level of 1 in lOO.OOO.43 Since carcinogens are assumed to
43     We note that the cancer risk from the carcinogenic metals must be summed to
ensure mat the summed risk is not greater than 1 in 100,000. Thus, when more man one
carcinogenic metal is emitted, the allowable ground level concentration for each
carcinogenic metal is less than the 10*5 Risk Specific Dose for that metal.

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pose a smaU but finite risk of cancer even at very low doses, the RSD reflects a cenain risk
level, corresponding to 1 chance in  100,000,  or 10'5 excess risk of cancer for the
maximally exposed individual if exposed continuously to multiple carcinogenic chemicals
for a 70-year lifetime. RACs for HC1 and Q2 are based on inhalation data, and a RAG for
lead is based on the National Ambient Air Quality Standard (NAAQS).

       To establish the Screening Limits for metals and HC1, air dispersion modeling was
applied to back-calculate maximum acceptable feed rates and stack emissions rates from
risk-based, acceptable ambient concentrations.  These calculations were performed for
various terrain types, effective stack heights, and land use classifications. The resulting
permissible Screening Limits reflect plausible, reasonable worst-case assumptions about a
generic facility that are not site-specific. The Screening Limits process provides a rapid and
convenient risk-based mechanism to determine compliance. Conservative assumptions
used to estimate health impacts exposure in the Screening  Limit process include: (1) use of
reasonable, worst-case estimate of dispersion of stack emissions; and (2) for the Tier I feed
rate Screening Limits, assuming that all metals and chlorine fed into the BIF in all
feedstreams are emitted (i.e., there is no partitioning to bottom ash or product, and not
removal by an air pollution control system).44   See 52 FR 17002 (May 6,1987) and 54
FR 43729 (October 26,1989).) Thus, assumptions and  the Screening Limits tend to err
intentionally on the side of protecting human health.45

     - If emission levels exceed the Screening Limits, (or if the owner/operator so elects)
the rule allows a facility to conduct its own site-specific air dispersion modeling in order to
establish metals, HO, and Q2 emission limits. Incorporation of site-specific information
allows less conservative assumptions (than the reasonable worst-case, nonsite-specific
defaults), to be used in the dispersion models. Consequently, site-specific air dispersion
modeling may predict lower ambient concentrations than the nonsite-specific modeling
reflected in the Screening Limits, thus allowing higher emissions and feed rate limits.
44    jo obtain credit for partitioning to residue or product and for APCS removal
efficiency, owners and operators must conduct emissions testing to demonstrate the overall
System Removal Efficiency (SRE) - partitioning plus APCS removal efficiency. The
Agency has not assumed an SRE in developing the Tier 1 feed rate Screening Limits
because there are many site-specific factors that can affect the SRE.
45    We note that the Screening Limits may not always be conservative, however.
Today's rule identifies criteria whereby the Screening Limits may not be used because they
may not be conservative.  See 266.106(7). That paragraph in the rule also gives tiie
Agency authority to determine whether the Screening Limits may not be protective in a
particular situation. In that case, the owner and operator must use the Tier HI procedures -
site-specific dispersion modeling.  '        :

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A. Health Effects Data.

       1. Carcinogens. Health effects evaluations for carcinogens have been summarized
in Pan Three, I. D, "Evaluation of Health Risk" in die April 27,1990 proposal (see 55 FR
17873). To summarize briefly, in contrast to noncarcinogens, carcinogens are assumed to
present a small but finite risk of causing cancer, even at very low doses.  The slope of the
dose-response curve in the low dose region is assumed to be linear for carcinogens.
Because of this, the slope of the curve in the low dose region may be used as an estimate of
carcinogenic potency.  The unit risk is defined as the incremental lifetime risk estimated to
result from exposure of an individual for a 70-year lifetime to a carcinogen in air containing
1 microgram of the compound per cubic meter of air (ug/m^). At an air concentration of 1
ug/nA the cancer potency slope is numerically equivalent to the unit risk.  Thus, at a
preselected risk level, the corresponding air concentration which would cause that risk may
be calculated by dividing the desired risk level by the unit risk value.  Although the
resulting value represents an air concentration with units of ug/nA this concentration is
referred to as the Risk Specific Dose (RSD).

       When exposed to more than one carcinogen, the Guidelines for Carcinogenic Risk
Assessment (51 FR 33992 (September 24, 1986)) recommend adding risks from the
individual  carcinogens to obtain the aggregate risk (i.e., cancer risks from exposure to
more than one carcinogen are assumed to be additive). For today's rule, the Agency has
proposed that an aggregate risk level for metals (i.e., arsenic, beryllium, cadmium, and
hexavalent chromium) of 10*5 is appropriate because it would limit the risk level for
individual carcinogens to the order of 10*6.  The Agency points out, however, that in
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.  See, e.g., 54 FR at 38049 (Sept 14,1989). Particular factors bearing on the
Agency's choice here include the wide array and potentially large volumes of carcinogenic
pollutants that can be emitted by these devices (unlike the situation in such rules as the
benzene NBSHAP when a single pollutant with well-understood effects was at issue), the
need to guard against environmental harm as well as harm to human health, potential
synergistic effects of the carcinogens emitted by these devices (which effects are not
accounted for by the risk assessment), and legislative history indicating Congressional
preference for parity of regulation between BIFs burning hazardous waste fuels and
hazardous waste incinerators (S. Rep. No. 284,98th Cong. 1st Sess. 38)).  In addition,

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the increased recognition of the need to control net air emissions of toxic pollutants
generally, manifest in Tide m of the Clean Air Act Amendments of 1990, influences the
Agency's choice of a conservative risk target in this rule. These same factors can also
influence choice of a risk level where the Agency is making site-specific determinations.

       The following section discusses comments on health effects data on carcinogens.

       a. Unit Risk Factors/Risk Specific Doses. A few commenters argued for deletion
of category C carcinogens from consideration in the risk assessment process.

       Given that the carcinogenic metals arsenic, beryllium, cadmium,  and hexavalent
chromium are classified as either A or B carcinogens, this discussion pertains only to the C
nonmetal Appendix  Vm compounds for which die Agency established 10"5 RSDs for
purposes of implementing the low risk waste exemption, risk assessments for cement kilns
with HC levels exceeding 20 ppmv, and health-based limits for Bevill excluded waste.

       As a conservative element in the risk assessment process, and especially for
purposes of implementing an exemption from some of the emission controls, EPA does not
believe that exposure to category C carcinogens should be ignored at this time for those
chemicals with cancer potency slopes. The classification schemes categorize chemicals
based upon weight of the evidence, not carcinogenic potency.  Therefore, a  highly potent
carcinogen may be classified in the C category and present a threat to health.

       b. Quality of the Toxicological Data Base. Several commenters questioned the
quality and extent of the toxicology data base and EPA's selection of specific studies used
to calculate the cancer potency factors and unit risk values for a particular chemical. For
example, one commenter noted that the molecular species of a metal compound emitted
from an incinerator may be markedly different from the metallic complex actually tested for
carcinogenicity and used to calculate that metal's cancer potency factor.  This would distort
the risk assessment process.  This same commenter argued that beryllium oxide, which
would be formed preferentially at the extreme temperatures of a furnace, is relatively inert
compared to the molecular complex of beryllium which forms the basis  of the cancer
potency factor. Another commenter contended that, in general, the less water soluble (and,
therefore, less bioavailable) metallic oxides are emitted from incinerators whereas the
metallic species tested for cancer were more water soluble and bioavailable (i.e., absorbable
into the organism).

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       EPA acknowledges the concern that die metal complex tested for carcinogenicity in
animals reflect that to which humans are exposed However, the particular metal complex
being emitted may not have been tested in animals.  In such cases, it is sometimes
necessary to use that toxicological data which is available (on the same metal but complexed
with a different ligand), limitations notwithstanding, until appropriate data on the complex
of concern become available. EPA believes the use of the available data base will result in
risk assessment methodology mat is protective of human health and the environment

       Moreover, EPA notes that soluble metallic salts may also be emitted under some
conditions (e.g., metallic chlorides). For screening purposes, the conservative assumption
that soluble (i.e., bioavailable) metallic complexes are emitted, is assumed to protect health.
For the site-specific risk assessment option, historical or test  burn data may be used to
identify probable emitted metallic species. If permit officials conclude during the permit
process that appropriate fate, transport, and toxicological data exist for the actual emitted
complex to support risk assessment, this could then be used in the site-specific risk
assessment option.

       c.  High Dose to Low Dose Extrapolation.  Several commenters questioned the
scientific merit of extrapolating from high dose experimental data to low dose cancer risks
using existing statistical models, asserting that the process is not biologically-based and is
extremely conservative (Le., overly health-protective). Two commenters asserted that the
linearized multistage model should not be applied to non-genotoxic  carcinogens because
such "carcinogens" promote rather than initiate cancer, thus acting as a classical toxicant
with a threshold. These commenters maintained that a chemical such as chloroform, which
they claim is non-genotoxic (i.e., has not tested positive in mutation assays), would have a
threshold below which there is no risk of cancer.  Another commenter argued that
biological evidence indicates a threshold for arsenic-induced cancer due to its known
benefit as an essential trace element at low doses. This same commenter asserted that
hexavalent chromium (Cr+6) is quickly converted in the body to the essential trace element
Cr+3 and, therefore, should be treated as a "threshold carcinogen."

      The Agency is following closely recent developments in  scientific consensus
regarding the basic molecular biology of cancer.  EPA will revise its Guidelines for
carcinogen risk assessment, and other guidance documents, to reflect developing scientific
theory on high to low dose extrapolation threshold effects, and other related issues. Until
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that tune, EPA will continue to use its current approach, believing that a more conservative
approach is warranted in the face of uncertainty.

       d.  Chromium Oxidation State.  Several commenters argued that the current
proposal does not differentiate chromium in the +6 oxidation state from chromium +3.
They contend that most chromium  emitted  from boilers, industrial furnaces, and
incinerators exists in the +3 state. Consequently, the proposed approach, which assumes
that all chromium is +6, may overstate risks drastically.  The commenters recommended
that EPA assume that only a fraction of the chromium emitted by incinerators exists in the
+6 oxidation state.

       EPA concludes that assuming that 100% of the chromium is in the hexavalent
oxidation state is a conservative assumption taken in the face of limited data. In a test46 of
hazardous waste incinerator emissions under varying levels of total chlorine in the waste
burned, a high percentage of the total chromium emitted was in the hexavalent state under
certain conditions. Until more data is available, showing consistently lower proportions of
Cr+6 under a variety of combustion conditions, EPA believes it is health-protective to
assume that chromium from incinerator emissions exists in the hexavalent state.  Facilities
may elect to conduct emissions testing to determine the actual emission rate of Cr+6.

       e.  Additive Risks.  One commenter criticized EPA's selection of 10" ^  as the
acceptable aggregate risk level (for carcinogenic metals) for deriving screening limits, and
claimed the selection is arbitrary and inconsistent with other EPA policy. EPA policy, the
commenter notes, has traditionally embraced a range of risks from 10~7 to 10"4, with the
final EPA-selected risk level dependent upon site-specific conditions (Le., characteristics
and size of die exposed population).

       EPA's rationale for selecting 10*5 risk for the MEI is described in the October 26,
1989 supplemental notice (54 Federal Register 43754).  In summary, EPA continues to
believe that the aggregate cancer risk to the MEI of 10"5 for metals is appropriate because:
(1) it provides adequate protection of public health; (2) it considers weight of evidence of
human caxcinogenicity; (3) it limits the risk from individual Group A and B carcinogens to
risk levels on the order of 10~*>; and (4) it is within the range of risk levels the Agency has
46    U.S. EPA, "Pilot Scale Evaluation of the Fate of Trace Metals in a Rotary Kiln
Incinerator with a Venturi Scrubber/Packed Column Scrubber, VoL I, Technical Results",
April 1989.
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used for hazardous waste regulatory programs.  See also the discussion in section HI.A.I
of Part Three above.

      2. 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
pollutants are present in concentrations great enough to overcome the homeostatic,
compensating, and adaptive mechanisms of the organism.  Thus, protection against the
adverse health effects of a toxicant is likely to be achieved by preventing total exposure
levels that would result in a dose exceeding its threshold. 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 Therefore,
the Agency has  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 established in today's final rule are
identical to those proposed.  (See Appendix H of the Supplement to Proposed Rule at 54
FR 43762 (October 26,1989)). (The Agency notes that it does not intend for RACs to be
used as a means of setting air quality standards in other contexts.  For instance, the RAC
methodology does not imply a decision to supplant standards established under the Clean
Air ACL)

      We note, however, that the RACs proposed in Appendix H of the supplement to
proposed rule (and promulgated today as Appendix IV to the rule) included both Agency-
verified and unverified values. Unverified values are subject to revision as the Agency's
Reference Dose Workgroup continues to establish verified inhalation RfDs. (Occasionally,
the Agency may also revise verified values based on new and significant information.)
Since the supplemental notice, the Workgroup has established inhalation RfDs for eight
compounds on proposed Appendix H (and promulgated Appendix IV to the rule).  The
basis for the newly-verified RfDs is set forth in the Health Effects Assessment Summary
Tables. Fourth Quarter-FYQQ. U.S. EPA, OFJIR 9200 6-303 (90-4), September 1990.47
Consequently,  RACs based on those RfDs are different from the proposed  and
promulgated RACs. The RACs based on verified inhalation RfDs are shown in the table
47     The document is available from the National Technical Information Service (NTIS),
5285 port Royal Road, Springfield, VA 22161, (703) 487-4600.  The document number is
PB90-921-104.
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below. EPA will use the omnibus permit authority of 270.32(b)(2) to use these revised
RACs where (he facts warrant.48
                  Compound
    RACin
Appendix IV of
  Final Rule
Acroelin (107-02-8)
Carbon Disulfide C75-15-0)
p-Dichlorobenzene (106-46-7)
Bromomethane (74-83-9)
Hydrogen Sulfide (7783-06-4)
Mercuiy (7439-97-6)
Methoxychlor (72-43-5)
Toluene (108-88-3)
     20
    200
     10
      0.8
      3
      0.3
     50
    300
RAC Based on
  Recently-
 Verified RfD
   (ug/mSl
      0.03
      3
    200
      2
      0.2
      0.08
      4
    500
       RACs  have  been derived from  oral reference doses  (RfDs)  for  those
noncarcinogenic compounds listed in Appendix VTO of 40 CFR Part 261 (except for lead,
HO, and Cl2) for which the Agency considers that it has adequate health effects data. An
oral RfD is an estimate (with an uncertainty of perhaps an order of magnitude) of a daily
oral dose (commonly expressed with units of mg/kg-day) 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 RfDs are subject to
change, EPA will undertake rulemakings as necessary if the derivative 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).  We
note that, in the interim before any such rulemaking is complete, and as discussed above,
4 8    EPA notes that permit writers choosing to invoke the omnibus permit authority of
270.32(b)(2) to add conditions to a RCRA permit must show that such conditions are
necessary to ensure protection of human health and the environment and must provide
support for the conditions to interested parties and accept and respond to comment. In
addition, permit writers must justify in the administrative record supporting the permit any
decisions based on omnibus authority.
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permit officials may use the omnibus permit authority49 of the statute to consider revised
health effects data in establishing permit conditions.

       Hie Agency's rationale for using oral RfDs as a basis for RAC-derivation is
described in 54 FR 43755 (October 26,1989). EPA believes the approach to derive RACs
is reasonable because: (1) the RfDs are verified by an EPA workgroup whose decisions
are subject to public review; (2) the  verification process addresses long term (lifetime)
exposure; (3)  the RfDs are based on the best available information meeting specific
scientific criteria; (4) the most sensitive individuals are considered; and (5) the RfD
determination takes into account the confidence in the quality of the information on which'
they are based.  Nevertheless, the Agency's Inhalation RfD Workgroup is developing
reference dose values (concentrations) for inhalation exposure for several chemicals, and
some are currently available.  As  reference concentrations are established by the
Workgroup, the Agency will consider the need to change the RACs established in today's
rule as discussed above.

       The final rule regulates HC1 emissions based on an annual exposure (long-term)
RAC of 7 ug/m3.50  The RAC is based on the threshold of priority effects resulting from
exposure to HC1. Background levels were considered to be insignificant given that there
are not many large sources of HC1 and that this pollutant  generally should not be
transported over long distances in the lower atmosphere.

       The Agency also proposed a  short-term (i.e., 3-minute exposure) RAC for HC1.
The Agency agrees with commenters, however, that the proposed RAC was not technically
supportable. See discussion in section V of Part Four of this preamble. Consequently, the
final rule does not establish a short-term RAC for Hd.

       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 ug/rn^, for purposes of this regulation, sources could contribute only up to
4 9     EPA notes that permit writers choosing to invoke the omnibus permit authority of
270.32(b)(2) to add conditions to a RCRA permit must show that such conditions are
necessary to ensure protection of human health and the environment and must provide
support for the conditions to interested parties and accept and respond to comment. In
addition, permit writers must justify in the administrative record supporting the permit any
decisions based on omnibus authority.
50     \].S. EPA, Integrated Risk Information System flRIS^ Chemical Files.  
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0.15 ug/m3. Given, however, that the lead NAAQS is based on a quarterly average, the
equivalent annual exposure is 0.09 u
       Finally, section 109 of the Clean Air Act (CAA) requires EPA to establish ambient
standards for pollutants determined to be injurious to public health, allowing for an
adequate margin of safety . Secondary NAAQS, also authorized by section 109, 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) used in today's
rule for Lead is based on the Lead NAAQS. As the Agency develops additional NAAQS
for toxic compounds that may be 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.
We note again that die reference air concentration values (and risk-specific dose values for
carcinogens) presented here in no way preclude the Agency from establishing NAAQS as
appropriate for these compounds under authority of the CAA.

       a. Derivation of Oral RfDs/RACs.  Many commenters responded to the issue of
derivation of oral RfDs/RACs, questioning  the scientific basis for the oral RfDs and
conversion of RfDs to RACs. Some commenters stated that use of oral RfDs do not factor
in differences in routes of exposure (e.g., absorption, first-pass effects) when extrapolating
from oral to inhalation routes of exposure.  As discussed above, we acknowledge the
limitations of developing RACs from oral RfDs but continue to believe the approach used is
reasonable and the best available approach until the Agency's Inhalation RfD Workgroup
can provide inhalation values.

       Other commenters directed their comments exclusively to lead, indicating that the
lead RAC was arbitrary. EPA has based the lead RAC on the National Ambient Air Quality
Standard (NAAQS).  This was done in part because no reference dose or cancer potency
slope is currently available for this metal. The final rule uses 10%, rather than 25% as is
used for other compounds, as an apportionment factor (as proposed) because the Agency is
particularly concerned with:  (1) the possible high contribution of lead exposure by indirect
pathways, particularly in urban environments; and (2) the growing concern of low level
lead exposure in children since the lead NAAQS was established  (The Agency currently
plans to propose to readjust die lead NAAQS in 1991.)

       b. Apportionment  Some commenters questioned EPA's proposal apportioning
75% of the RfD to other non-specified sources, thus causing the RAC to correspond to
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 25% of the RfD. the commenters indicated that the figure of 75% from other sources was
 arbitrary and could vary from one chemical to another. They suggested that unless other
 sources of exposure were identified, the RAC should reflect 100% of the RfD.

       EPA has chosen a fraction (25%) of the RfD to serve as the basis for the RACs
 because indirect pathways, known to contribute to risks, are not quantified in these
 regulations. Even apart from exposures contributed by sources separate from the boiler,
 industrial furnace, or incinerator, indirect pathways from emissions from these devices
 themselves may contribute 75% or more to risk.  Such indirect (i.e., non-inhalation)
 pathways include deposition of emitted chemicals on:   (1) gardens and crops directly
 consumed by humans; (2) meadows  used for grazing  by beef cattle and other edible
 livestock;  and (3) meadows  and fodder used by dairy cattle (and subsequent milk
 consumption by humans).

       Such real exposures, which are not quantified in these rules, are accounted for by
 the allowance for 75% contribution from other sources. Moreover, it is  questionable
 whether any single  facility should be  allowed to consume  100% of an individual's
 exposure allowance, above which any further exposure might cause adverse health effects.

 B. Air Dispersion Modeling

       The Agency used air dispersion  modeling to develop the Screening Limits and
 dispersion modeling is available as the  exposure assessment component of the site-specific
risk assessment option.  A more extensive  discussion of air dispersion modeling is
included in the 1989 supplemental notice (see 54 FR 43752-54). This discussion focuses
on derivation  of Screening Limits, wherein  the dispersion models are  used to "back-
calculate" emission rates from acceptable ground level concentrations. The section is also
 applicable to dispersion modeling used for the risk assessment option (where ground level
concentrations are predicted from estimated emissions rates). The reader is referred to this
discussion for further information about  air dispersion modeling. It should  be noted that
for die purposes of the risk assessment option,  more site-specific information may be used
in place of some of the conservative  default  assumptions used to derive the Screening
Limits, generally resulting in lower predicted ambient air concentrations.

       1.  Option for Site-Specific Modeling.  In responding to this provision in the
proposal, many commenters argued for procedures which would allow greater flexibility in
the air dispersion modeling process. Many commenters seemed to confuse the issues of
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dispersion modeling used for the Screening Limits, and modeling for the site-specific risk
assessment  EPA concedes that many assumptions used to develop the Screening Limits
are, by design, conservative to ensure that the Limits are protective in most cases. These
assumptions do not apply, however, when an owner or operator conducts site-specific
dispersion modeling under the Tier m standards.  For site-specific dispersion modeling,
procedures specified in EPA's Guideline on Air Quality Models must be used.

       2.  Terrain-Adjusted Effective Stack Height.  Two commenters stated that in
adjusting the stack height to account for local terrain and differentiating for terrain in the
screening limits, EPA is "double counting" the influence of terrain unnecessarily.  One
commenter added that such terrain adjustment of stack height is not supported by the
current EPA Guideline on Air Quality Models (Revised*) and should be eliminated.

       EPA acknowledged mis "double counting" of terrain in the supplement to the
proposed rule (54 FR 43759), stating that this additional conservatism is necessary to
account for the wide range of terrain complexities encountered at real facilities. EPA
continues to believe that this double counting is necessary.  Without this conservatism,
additional criteria would have to be added to the existing list (see 266.106(b)(7)) for
determining when the screening limits may not be conservative and, thus, may not be used.
Commenters did not propose (and provide support for) additional criteria for determining
when the use of less conservative  screening limits would be appropriate. Further, EPA
believes that additional criteria would complicate and delay the implementation of the rule
by placing additional burden on regulatory officials. Moreover, if a facility cannot meet the
screening limits, men site-specific dispersion modeling may be used to demonstrate
compliance with the Tier in standards.  Detailed, comprehensive dispersion modeling
generally costs less than $5,000 and* thus, should not pose a substantial burden. In fact,
many BIFs have already conducted such modeling to comply with applicable standards
under the Clean Air Act Finally,  the final rule minimizes the burden of dispersion
modeling by allowing the use of screening models.

       3.  Conservatism in Screening Units.  Five commenters stated  that EPA's
approach  to setting the screening limits is  overly conservative and illustrated this by
calculating the difference in estimated ground level concentrations using site-specific
information as opposed to die default assumptions recommended for the Screening Limits.

       It should be noted that the Agency would  expect that the use of site-specific
information would lead to higher emission limits mat under the screening limits.  However,

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the Agency developed feed rate and emission rate screening limits with the intent of
minimizing the need for site-specific dispersion modeling and thus reducing the burden of
demonstrating compliance with the emissions standards. To ensure that the limits are
protective in most cases, however, the Agency derived the limits using conservative
assumptions. The Agency believes that, although the assumptions are reasonable, they
would likely limit emissions by a factor of 2 to 20 times lower than would be allowed by
site-specific dispersion modeling (54 FR 43758).
                                    i
       4. GEP Stack Height. Two commenters stated that EPA should not impose a GEP
stack height limitation for existing stacks. The commenters went on to state that EPA
should allow modeling of emissions at actual stack height for existing stacks or, at a
minimum,  adopt a grandfather provision to exclude GEP from applying to stacks
constructed prior to December 31,1970. One commenter also indicated that EPA should
recognize that the stack height used for conducting a site-specific dispersion modeling
analysis may exceed GEP formula height, as allowed under Section 123 of the Clean Air
Act

       The Agency maintains that in complying with the metals and HC1/C12 controls
credit will  not be allowed for stack heights greater than GEP.  GEP stack heights are
determined in a manner consistent with the Guideline for Determination of Good
Engineering Practice Stack Height (Technical Support Document for the Stack Height
Regulations), Revised (EPA 4507 48OO23R).

       EPA's position here is consistent with the prohibition  on using physical stack
height in excess of GEP in the development of emission limitations under EPA's Air
Program at 40 CFR 51.12 and 40 CFR 51.18.  Stack heights higher than GEP cannot be
used for compliance purposes because such stacks merely provide added dispersion and
dilution of ambient levels.  EPA prefers that pollutants be removed from the stack gas to
avoid build-up of persistent pollutants (e.g., metals) in the environment and subsequent
indirect exposure through, for example, the food chain. In addition, better dispersion of
emissions of carcinogenic compounds can merely expose larger populations to (albeit
lower) concentrations of pollutants and may not decrease the aggregate population risk
(i.e., cancer incidents/year in the affected population).

       5. Phone Rise Table. One commenter recommended that EPA extend Table F-2
(plume rise) and Tables E-l through E-10 (feed rate and emissions screening limits) of the
October 26,1989 supplemental notice to account for the high flow rates typical of many
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cement plant stacks. Another commenter stated that the effective stack height of most utility
boilers exceeds the mmriimim stack height contained in Tables E-l through E-10. One
commenter indicated that the plume rise values presented in Table F-2 are not conservative
for conditions of neutral atmospheric stability at average to high wind speeds or for stable
atmospheric conditions at all typical wind speeds. This commenter added that the screening
limits based on Table F-2 plume rise may not be conservative for regions having complex
terrain.

      For the final rule, the plume rise values presented in Table F-2 of the supplement to
the proposed rule were revised and the table was expanded to include higher stack exit flow
rates indicative of cement kiln stacks (exit flow rates were increased up to a level of 200
m^/s). See Appendix VI to the final rule. The plume rise table values were originally
developed based on plume rise equations presented in the 1979 User's Guide to the
Industrial Source Complex (ISC) model The plume rise formulation in the ISC model has
since been changed to correspond to the way other EPA models determine plume rise.
Consequently, the entire table was revised, based on conservative application of the
updated neutral and stable buoyant plume rise equations.51  The revised values of plume
rise represent the lowest value of conservative stable buoyant and neutral buoyant plume
rise for each flow rate/temperature level

      The range of terrain-adjusted effective stack heights, shown in Tables E-l through
E-10 of the supplemental notice, was not increased beyond the height of 120 meters. This
height was determined to be the maximum terrain-adjusted effective stack height based on
the stack parameter and site location data used in the development of the dispersion
coefficients (as described in Appendix F of the proposed, supplemental rule).  Facilities
with terrain-adjusted effective stack heights that exceed 120 meters have the option of
conducting site-specific dispersion modeling to demonstrate compliance.

       6. Compliance by Manipulating Effective Stack Height. One commenter claimed
that facilities may elect to circumvent compliance by manipulating their effective stack
heights.  This commenter added that additional exposures could result from the increased
dispersion from taller stacks. The Agency acknowledges that an owner or operator could
increase  physical stack height up to the GEP maximum to achieve better dispersion and
hence a higher allowable emission rate. The Agency maintains, however, that it is more
 51    Memorandum from Sue Templeman, Radian Corp., to Dwight Kustick, EPA,
 entitled "Derivation of Plume Rise Values for BIFs", dated November 30,1990.
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 protective of human health and the environment (see discussion in section HLB.4 above)
 and it may be more cost-effective to upgrade emission control equipment to state-of-the-art
 control, rather than to increase stack height, particularly given that the Agency plans to
 consider in the future whether additional controls are needed to better control metals
 emissions. See discussion in section section I of Part Three of this preamble.

       7. Effect ofHCl Emissions on Acid Rain. One commenter disagreed with the use
 of Screening Limits for HQ which are based solely upon effective stack height, terrain and
 land use. This commenter maintained that this approach ignores the effects of HC1 in
 atmospheric reactions and acid rain.

       Addressing potential effects of HQ in atmospheric reactions and acid rain is beyond
 the scope of this rule.  The screening limits were developed to protect human health in the
 vicinity of facilities burning hazardous waste.

       8. Building Wake Effects.  One commenter stated that emissions limits based on
 effective stack height, terrain, and land use would not be conservative in cases where
 stacks are subject to building wake effects. This commenter added that only consideration
 of building wake effects will lead to conservative concentrations for stacks influenced by
 nearby structures and recommended that site-specific dispersion modeling be required in all
 cases where the "Guideline for Air Quality Models (Revised)" indicates the necessity for
 consideration of building wake effects.

       The development of the conservative dispersion coefficients incorporated an
 eleventh hypothetical  source in order to represent facilities whose release heights do not
 meet good engineering practice and whose plumes would thus be subject to building wake
 effects (54  FR 43752).  In addition, the Agency acknowledges that  the dispersion
 coefficients used to establish the Tier I and n Screening Limits may not be conservative in
extremely poor dispersion conditions or when the ambient-air receptor is located close to
 the source and has therefore defined five situations for which the permit writer should
require site-specific dispersion modeling (54 FR 43754). Furthermore, the Agency is
 reserving the right to require that a site-specific dispersion modeling analysis be conducted,
 irrespective of whether the facility meets the specific Screening Limits. Thus, the permit
 writer has the option of overruling use of Tier I or H, if a probability exists that application
of this methodology would not be protective of the health-based standards. The Tier HI
approach of conducting site-specific dispersion modeling requires incorporation of building
wake effects, as necessary, in the modeling analysis. The Tier I and n Screening Limit
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methodology was not further modified to account for these factors, as it already embodies
repeated use of conservative assumptions.

C. Consideration of Indirect Exposure and Environmental Impacts

       1. Indirect Exposure. During the proposal stages of these regulations, a few
commenters recommended incorporating indirect exposure pathways into the risk
assessment process. Indirect exposure is defined, in these.regulations, as any exposure
pathway other than direct inhalation of emissions from a boiler or industrial furnace.  One
commenter maintained that emissions such as metals, chlorinated dioxins, and furans
would be environmentally persistent and able to enter the food chain after deposition on the
ground (including crops, pasture land, surface waters). Consequently, the commenter
argued that indirect exposures should be factored into the risk assessment

       EPA recognizes that the contribution of indirect pathways may be significant.
However, the Agency believes that other conservative procedures, such as apportioning
75% of exposures to either indirect pathways or other emission sources (that can contribute
to background levels) in the calculation of RACs, will help offset the contribution of
indirect pathways.  Another significant source of conservatism, offsetting the contribution
of indirect pathways,  is represented by the inherent uncertainty, and consequent
conservatism, in the models used to estimate unit risk values.  Use of the MEI in the
Screening  Limits procedure comprises yet another conservative element in the risk
assessment process which would offset direct estimation of indirect pathway exposure.
Therefore,  the Agency has not modified the risk assessment process to address indirect
pathways.

       2. Non-human Health Related Environmental Impacts.  One commenter noted that
for many pollutants, environmental standards for certain flora and fauna may be more
stringent than for humans. Therefore, the effect on non-human receptors should not be
ignored in the regulations and the environmental risks should be evaluated.

       EPA is concerned about the potential effects of BEF emissions on non-human
receptors.  While some environmental standards are available for the protection of
environmental receptors (notably EPA water quality criteria for aquatic organisms),
methods for quantifying exposure and defining acceptable levels for non-human receptors
are still largely in the developmental stages. Thus, until these critical procedures are better
established, the Agency is not requiring such an evaluation at this time. However, as noted
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 earlier, some of the conservatism in the human health risk assessment is designed to
 compensate for the absence of direct environmental standards.

 D. Acceptable Risk Level for Carcinogens

       Today's rule limits die incremental lifetime cancer risk to the hypothetical maximum
 exposed individual (MEI) to Ifr5. This risk level is within the range of levels historically
 used by EPA in its hazardous waste and emergency response programs - 1(H to 1(H>.

       Under the rule, we are limiting the aggregate risk to the MEI from carcinogenic
 metals to 10~5, and the aggregate risk from carcinogenic organic compounds (dioxins and
 furans and other PICs under provisions of the alternative HC limit) to 10~5. This will limit
 in most cases the risk from individual carcinogenic compounds to levels on the order of
 10'6 but below  !0~5. The rule does not require that the risk from carcinogenic organic
 compounds be added to the risk from carcinogenic metals. This is because the Agency
 does not believe it is appropriate to sum the risk from metals (i.e., arsenic, beryllium,
 cadmium, and chromium) that are known or probable human carcinogens (Group A or B
 carcinogens  under the weight-of-evidence approach) with the risk from organic
 compounds, many of which are possible human carcinogens (Group C carcinogens).

       In selecting a 10~5 aggregate risk threshold level for this rule, we considered risk
 thresholds in the range of 10*4 to ig-6, me range the Agency generally uses for various
 aspects of its hazardous waste programs.

       We considered limiting the aggregate risk to the MEI to 10'6 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 1(H>, 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"4.  An
aggregate risk threshold of 10~* would result in limiting the risk level for individual
carcinogens on the order of 1CT5. We did not select a 10"4 aggregate risk threshold for this
proposed rule for a number of reasons. In selecting the appropriate risk level for a
particular regulatory program, the Agency 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.  The Agency believes that a
10~5 risk level is appropriate for this rule because: (1) the rule limits emissions considering

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only direct exposure via inhalation of dispersed emissions. Other routes of exposure (e.g.,
soil ingestion, uptake through the food chain) are not accounted for by this methodology,
which means the risk is somewhat higher, (2) the carcinogenic metals that the rule controls
are Group A or B (i.e., known or probable) human carcinogens; (3) we are concerned
about the potential risks posed by the unknown pollutants these devices can emit - Le.,
products of incomplete combustion (PICs).52; and (4) the 10"5 risk level does not result in
a rule that poses a substantial burden on the regulated community given that it is neither a
major rule as defined by Executive Order 12291 nor will it significantly impact small
entities.

       When the proposed regulations were published and comments were solicited from
affected parties, several commenters responded to the issue of acceptable risk levels for
exposure to carcinogens. These commenters questioned the basis of 10*5 as representing
an acceptable risk level. They maintained that the discussion in the rule, serving as the
rationale or justification for selecting this level of risk, was inadequate. Others asserted that
the selected acceptable level of cancer risk was not consistent with other regulations
(specifically, 10~4 cancer risk to the MEI was used to set a national emission standard
(NESHAP) for benzene, and 10*5 for individuals living "some distance from the source").

       The Agency continues to believe that the aggregate cancer risk to the MEI of 10'5 is
appropriate here because: (1) it provides adequate protection of public health; (2) it limits
the risk from individual Group A and B carcinogens to risk levels on the order of lO^; and
(3) it is within the range of risk levels the Agency has used for hazardous waste regulatory
programs. See also discussion in section m.A above.

E. Use of MEIlConsideration of Aggregate Risk

       The Agency considered the use of aggregate population risk or cancer incidence
(i.e., cancer incidents per year) 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 emission 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
 52    This rule is, thus, unlike the Benzene NESHAP where EPA targeted one known
 pollutant with known effects.

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 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.
       Several commenters addressed the issue of using the mayimutp exposed individual
 (MEI) as a basis for risk estimation and recommended using population (aggregate) risks as
 a more realistic alternative. They maintained that health risks are overstated if based only
 on exposure of the Maximum Exposed Individual (MEI). Aggregate population-based
 exposures, which are usually much lower would more realistically represent site-specific
 health risks. Many commenters noted that using the MEI exposure implicitly assumes that
 population risks are
       EPA believes that evaluation of the MEI only (and not aggregate population risk) is
usually a conservative feature of the risk assessment For screening purposes, a simplified
approach is necessary. While site-specific demographic data is usually readily available
from 1980 census data, its incorporation into a screen would complicate the screening
process unnecessarily.  Calculation of screening limits based on the risk to the MEI
requires much less site-specific information, facilitating application of the screen to a broad
range of sites. If the facility does not meet the screening limits, the option of site-specific
risk assessment is still available. While MEI exposures are estimated routinely in a site-
specific risk assessment, aggregate population risks may also be estimated, if desired.

       Several commenters also contended that even the risk estimates for the MEI may be
overly health-protective since the MEI is assumed to reside at this high exposure location
24 hours per day, 365 days per year, for a 70-year lifetime. A more fair evaluation of MEI
risk would account for the attenuating effects of time spent indoors and off-site, and
include estimates of average residence  times and facility lifetimes.  Moreover, some
exposure assessments assume the MEI is located at the point of maximum ground level
concentration predicted by the dispersion model, when in fact, no one may live at this site.

       EPA acknowledges that use of the hypothetical MEI is a conservative feature of the
rule but maintains that it is reasonable to balance against the potentially nonconservative
features of the rule discussed below.

F. Risk Assessment Assumptions

       As indicated in the above discussion, 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.
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      Conservative assumptions include the following:

    Individuals reside  at  the  point of maximum annual  average 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 noncarcinogenic health determinations, background exposure already amounts to
     75% of the RID. This includes other routes of exposure, including ingestion and
     dermal. Thus, the BIF is only allowed to contribute 25% of the RID via direct
     inhalation. The only exception is for lead, where a BIF is only allowed to contribute
     10% of the NAAQS. This is because ambient lead levels in 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.

    Risks are considered for pollutants that are known, probable, and  possible  human
     carcinogens.

    Individual health risk numbers have large uncertainty factors implicit in their
     derivation to take into effect the most sensitive portion of the population.


      Nonconservative assumptions include the following:

    For carcinogenic compounds, indirect routes of exposure are not considered, such as
     uptake of arsenic, beryllium, c^H^iim and chromium through the food chain.

    Although emissions are complex mixtures,  interactive effects of threshold  or
     carcinogenic compounds have not been considered in this regulation because data on
     such relationships are inadequate.

    Environmental effects (i.e., effects on plants and animals) have not been considered
     because of a lack of adequate information. Adverse effects on plants and animals may
     occur at levels  lower man those that cause adverse human health effects. (The
     Agency is also developing procedures and requesting Science Advisory Board review
     to  consider environmental effects resulting from emissions from all categories of
     waste combustion facilities.)


      Many commenters responded broadly on the impact of assumptions and uncertainty

in risk assessment While generally supporting the concept of risk assessment, some

asserted mat EPA's proposed assumptions were too  conservative regarding estimated
emission levels, dispersion  modeling, and health impact estimation. Further, they

maintained that assumptions were not well enough justified and the conservative bias used
for each of the multiple assumptions required in a risk assessment tends to accumulate,
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 resulting in gross over-estimation of health impacts. Some of the specific assumptions that
 comroenters considered too conservative are discussed in the following paragraphs.

       Two commenters asserted that emission control technology should not be assumed
 absent when estimating emission levels. One commenter recommended that sensitivity
 analysis be incorporated into the risk assessment process.  This  commenter also
 recommended incorporation into the risk assessment of population mobility (i.e., time
 spent away from the site), facility lifetimes less than 70 years, and an attenuation factor for
 time spent indoors, rather than assume 24 hr/day, 70-year exposure.

       Many of the respondents argued that economic impacts resulting from overly-
 conservative risk assessments are substantial.  To avoid some of the default assumptions is
 also burdensome in the commenters judgment,  requiring trial burns, emissions
 measurements, slag and product assays, and detailed air quality dispersion modeling.

       Although many of the assumptions discussed by the commenters are conservative
 in nature, it is difficult to determine how less conservative assumptions could be used in
 light of the considerable associated uncertainty.  Much of the conservatism referred to
 originates from assumptions used to derive screening levels. When screening levels are
 derived, either (1)  no site-specific information is available (nor may be assumed if the
 procedure is intended to screen a variety of sites); or (2) incorporation of site-specific
 information in the derivation of screening levels would so complicate the process as to
 render it prohibitively time-consuming and defeat its utility as a screen. Thus, in light of
 the uncertainty (i.e., no site specific information), conservative assumptions are used to
 derive the screening limits that EPA believes to be protective of human health and the
 environment

       If the facility fails to meet the screening criteria, the option of site-specific risk
 assessment is still available. For site-specific risk assessment, more realistic and less
 conservative assumptions may be incorporated, reflecting actual site or facility conditions.

 V.  Controls for Emissions of Toxic Metals

      The Agency has identified 12 toxic metals in Appendix vm of 40 CFR Pan 261
that may pose a hazard to human health and the environment: antimony, arsenic, barium,
 beryllium, cadmium, hexavalent chromium, lead, mercury, nickel, selenium, silver, and
thallium. Five of these metals (or their compounds) are known or suspected carcinogens:
arsenic, beryllium, cadmium, hexavalent chromium, and nickel.

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       Many of these toxic metals are contained in hazardous waste that is burned in
boilers and industrial furnaces. Many hazardous waste fuels contain metals at levels orders
of magnitude higher than levels found in No. 6 fuel oil. Metal-bearing wastes typically
used  as fuel in boilers and  industrial  furnaces  include spent halogenated and
nonhalogenated degreasing solvents used for metals cleaning, paint manufacturing wastes,
and other organic liquid wastes with high heating values. Currently, metals emissions
from the burning of these wastes are not controlled under RCRA for boilers and the types
of industrial furnaces that bum hazardous wastes.  Emissions of carcinogenic metals can
potentially result in increased lifetime cancer risks of greater than 1 x 10*4 g^ emissions of
noncarcinogenic metals such as lead can result in ambient levels that result in adverse health
effects.

       Today's final rule promulgates the controls as discussed in the October 1989
supplement to the proposed rule (see 54 FR 43728-29).53 See 266.106.  The rules
establish metals emission limits for 10 toxic metals54 listed in Appendix VHI of 40 CFR
Part 261 based on projected inhalation health risks to a hypothetical maximum exposed
individual (MEI). The standards for the carcinogenic metals (arsenic, beryllium, cadmium,
and chromium) limit the increased lifetime cancer risk to the MEI to a maximum of 1 in
100,000. The risk from the four carcinogens must be summed to ensure that the combined
risk is no greater than  1 in 100,000. The standards for the noncarcinogenic metals
(antimony, barium, mercury, silver, and thallium) are based on Reference Doses (RfDs)
below which adverse health effects have not been observed. The standard for lead is based
on the National Ambient Air Quality Standard (NAAQS) for lead.

       The owner and operator must analyze the hazardous waste to be burned and comply
with the standard for each of the 10 metals that could reasonably be expected to be in the
53     Given time constraints in developing the final rule for promulgation, response to
major comments could not be provided in the preamble. Responses to comments are
provided in the Comment Response Document for the BIF Regulation.
34     AS proposed, the rule does not limit emissions of nickel and selenium (see 54 FR
43729). Limits cannot be established for selenium because the Agency has inadequate
health data to establish a reference air concentration. Nickel is not controlled because the
two nickel compounds suspected at this time of being potential human carcinogens, nickel
carbonyl and subsulfide, are not likely to be emitted from combustion devices, given their
highly oxidizing conditions. In the 1989 supplemental notice to the proposed rule, EPA
requested comments on whether the reduced carcinogenic forms of nickel were likely to be
emitted from hazardous waste burning devices, especially those furnaces that may not use
highly oxidized conditions. However, the Agency did not receive any comments on mis
issue pertinent to boilers and industrial furnaces.   .   
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 waiste.  The metals excluded from analysis must be identified and the basis for their
 exclusion explained to ensure that there is adequate justification for not analyzing for a
 particular metal

       The standards are implemented through a three-tiered approach. Compliance with
 any tier is acceptable.  The tiers are structured to allow higher emission rates (and feed
 rates) as the owner or operator elects to conduct more site-specific testing and analyses
 (e.g., emissions testing, dispersion modeling). Thus, the feed rate limits under each of the
 tiers are derived based on different levels of site-specific information related to facility
 design and surrounding terrain. Under Tier I (see 266.106(b)), the Agency has provided
 conservative waste feed rate limits in reference tables as a function of effective stack height
 and terrain and land use in the vicinity of the stack. The owner or operator demonstrates
 compliance  by waste analysis, not emissions testing  or dispersion modeling.
 Consequently, the Tier I feed rate  limits are  based an an assumed reasonable, worst-case
 dispersion scenario, and an assumption that all metals fed to die device are emitted (i.e., no
 partitioning to bottom ash or product, and no removal by an air pollution control device
 (APCD)).

      'Under Tier n (see 266.106(c)), the owner or operator conducts emissions testing
 (but not dispersion modeling) to get credit for partitioning to bottom ash or product,  and
 APCD removal efficiency. Thus,  the Agency has developed conservative emission rate
 limits in reference tables, again as a function  of effective stack height and terrain and land
 use in the vicinity of the stack.  The Agency also assumed reasonable, worst-case
 dispersion under Tier n.

       Under Tier m (see 266.106(d)), the owner or operator elects to conduct emissions
 testing and site-specific dispersion modeling to demonstrate that the actual (measured)
 emissions do not exceed acceptable levels considering actual (predicted) dispersion.

       The metals controls apply both to facilities applying for a Part B operating permit
 and to facilities operating during  interim status.  See section VH of Part Three of  this
 preamble for discussion of how the standards  apply during interim status.

A. Background Information.

       The following sections summarize EPA's regulation of metals emissions from
 boilers and industrial furnaces under other statutes, the 1987 proposed rule and comments
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received on that proposal, and the basis for the 1989 revision to the proposed rule and
comments received on that revised approach.

       1. Metals Standards  Under Other Statutes.  As discussed below, EPA has
promulgated standards applicable to boilers and industrial furnaces under other statutes for
some but not all of the 10 toxic metals controlled by today's rule. Under the Clean Air Act
(CAA), EPA established National Emissions Standards for Hazardous Air Pollutants
(NESHAPS) for arsenic, beryllium, and mercury for certain categories of sources (40 CFR
Pan 61). These emission standards were developed considering the quantities and types of
metals emissions from various source categories, current control practices, and the
economic 'impacts of reducing emissions. In addition, EPA has established National
Ambient Air Quality Standards55 (NAAQS) for lead and paniculate matter. These ambient
standards are implemented by states under the State Implementation Plan (SIP) program to
control major sources of lead and paniculate emissions. The Agency does not believe that
lead emissions standards have been established under the SIPs for any boilers and for
many industrial furnaces that  burn hazardous waste fuels (e.g., cement and light-weight
aggregate kilns) because they are not major lead emitters as defined under the NAAQS.
Therefore, EPA believes that today's metals controls are not redundant to existing Agency
standards, and, thus, are necessary to ensure adequate protection of human health and the
environment

       Paniculate- emission standards, however, established  under  the SIPs in
conformance with the paniculate NAAQS,  or by EPA as New Source Performance
Standards (NSPS), do apply to some boilers and industrial furnaces that bum  hazardous
waste. The paniculate standards generally limit metals emissions to the extent that state-of-
the-art paniculate control technologies will allow. High efficiency electrostatic precipitators
(ESPs)  or fabric filters are usually required  to meet these  standards. However, these
paniculate emission standards may not adequately control metals emissions from the
burning of hazardous wastes in many boilers and industrial furnaces for several reasons:
(1) the paniculate standards do not apply to gas and oil-fired boilers (which represent a
large number of hazardous waste fuel burners); (2) smaller coal-fired boilers are not subject
to NSPS standards and may not be required under the SIPs to be equipped with ESPs or
fabric filters;  (3) large volumes of hazardous waste fuels are burned by light weight
 55    We note that the reference air concentration values fornoncarcinogens and risk-
 specific dose values for carcinogens established by today's rule are not intended to, and in
 no way, preclude the Agency from establishing NAAQS as appropriate for these
 compounds under authority of the Clean Air ACL

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 aggregate kilns that are equipped with low-pressure wet scrubbers that may not be highly
 efficient at collecting  particulates in the less than 1 micron range, the size range that
 contains the bulk of die paniculate metals; and (4) the risks posed by metals emissions from
 these boilers and industrial furnaces that are equipped with ESPs, fabric filters, and wet
 scrubbers can increase substantially when hazardous waste fuel is burned since the levels
 of some metals, particularly chromium and lead, can be much higher in hazardous waste
 thanincoaL

       2. 1987 Proposed Rule. The 1987 proposed rule would have established a four-
 tiered standard to control emissions of arsenic, cadmium, hexavalent chromium, and lead.
 Each Tier represented a standard protective on its own, and demonstration of compliance
 with any Tier would have been sufficient  Tiers I through ffl established hazardous waste
 metals concentrations, feed rates, and emission screening limits, respectively, as a function
 of device type and thermal capacity.  Tier IV would have provided for site-specific
 dispersion modeling to demonstrate that, when the screening limits were exceeded,
 emissions would nevertheless not pose an unacceptable health risk.  Data available to the
 Agency indicated that only four of the 12 toxic metals listed in Appendix Vm of Pan 261
 were likely to be present in hazardous waste burned in boilers and industrial furnaces at
 levels posing a significant health risk. The permit writer would have determined on a case-
 by-case basis if any of the other toxic metals were present at levels posing a significant
 risk.

       Public comments submitted on the  1987 proposal stated that EPA's database on the
 metals composition of hazardous waste was both limited and out of date in light of the
 Agency's data collection efforts at that time and the HSWA statutory requirement to ptetreat
 waste that heretofore had been land disposed. As a result of HSWA, more hazardous
 waste is being burned, and pretreatment operations are often likely to involve combustion.
 The hazardous waste burned currently and in the future in boilers and industrial furnaces
 may include toxic metals other than the four targeted for regulation in the 1987 proposal.
 Therefore, tile Agency requested comment in the October 1989 supplemental notice on
 expanding the list of regulated metals to include all 10 Appendix VHI metals. (Nickel and
 selenium were not included as discussed above.) In addition, if standards for all of the
 toxic metals were included in die rule,  the burden on permit writers would actually be
reduced because explicit standards would be provided for all metals of potential concern.
Without explicit standards, permit writers would have to rely on the omnibus permit
 authority of the statute to add permit conditions as necessary to protect human health and
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the environment.  Using the omnibus permit authority can involve a lengthy and
cumbersome interaction between permit officials and the applicant

       3.  1989 Supplement to Proposed Rule. Based on public comments submitted on
the 1987 proposed rule and on additional evaluation of the risk assessment approach used
for the proposal, the Agency discussed in the 1989 supplemental notice whether to (1)
expand the list of metals for which emissions standards would be established in the rule to
include all the toxic metals listed in Appendix Vm of Pan 261 (except nickel and selenium,
for the reasons discussed above); (2) establish the screening limits as a function of effective
stack height, terrain, and land use rather than as a function of device type and capacity; and
(3) rather than provide the screening limits in the rule itself as proposed in 1987, provide
them in a guidance document that would be entitled "Risk Assessment Guideline (RAG) for
Permitting Hazardous Waste Thermal Treatment Devices".

       a.  Expanded List of Metals.  In the 1989 supplemental notice, EPA proposed to
expand the list of metals for which emissions standards would be established in the rule to
include antimony, arsenic, barium, beryllium, cadmium, hexavalent chromium, lead,
mercury, silver, and thallium.  Thus, of the 12 toxic metals listed in Appendix VM, only
selenium and nickel would not be controlled for reasons discussed above. Today's final
rule establishes standards for all 10 metals. We note that the controls apply only to metals
that are present in the hazardous waste feed at detectable levels using procedures specified
inSW-846.  See 266.106(a).

       b. Revised Basis for Screening Limits. In the 1989 supplemental notice, EPA also
proposed to revise the bases for the feed rate and emission rate screening limits to correlate
them with stack height and terrain and land use in the vicinity of the facility because these
parameters more directly relate emission controls  to key  parameters that affect the
dispersion of emissions, and ultimately, ambient levels (i.e., more so than the proposed
approach of correlating the screening limits to device type and heat input capacity). When
developing the Tier I through Tier ffl screening limits proposed in 1987, the Agency made
a simplified assumption that effective stack height correlated with thermal capacity (e.g., if
the thermal capacity of one device was 10 percent greater than the thermal capacity of
another, the effective stack height was also 10 percent greater). The Agency acknowledges
that this assumption may not  always hold. Stack height is often more a function of the
height of nearby buildings and surrounding terrain than a function of the heat input capacity
of the device. Thus, the final rule correlates the Tier I and Tier n screening limits to stack
height, terrain, and land use.

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       c. Establishing the Screening Limits in the Rule. As originally proposed in 1987,
the final role incorporates the Her I feed rate screening limits and the Her n emissions rate
screening limits in the rule itself rather than in a separate guidance document  Our concern
(and many commenters concurred) is that a guidance document would not carry the weight
of a regulation - permit writers would be free to accept or reject the guidance (i.e., in this
case, the screening limits and the reference air concentration (RACs) and risk-specific dose
(RSD) values used to develop the limits). In addition, permit writers would be obligated to
justify use and appropriateness of the guidance on a case-by-case basis. This would place
a substantial burden on the permit writer  and result in inconsistent, and  perhaps,
inappropriate permit conditions.  Finally, implementing the  emission standards  during
interim status as required by the final rule would  be  virtually impossible without
incorporating the screening limits and RACs and RSDs in the rule.

       We note that revisions to the RACs and RSD values will undoubtedly need to be
made over time as the Agency obtains additional health effects information on the regulated
pollutants, and corresponding revisions to the screening limits, will be made by  formal
rulemaking (i.e., proposed revisions, opportunity for public comment, and promulgation
of final revisions). In the interim, however, permit writers may apply stricter limits than
contained in the rule (if the facts justify it) pursuant to the omnibus permit authority56 in
Section 3005(c)(3).

       In the 1989 proposal, as a possible alternative to monitoring waste feed  rates and
compositions, EPA requested comment on using the results of analyses of emission control
residues to monitor compliance with the metals emission standards. Several commenters
supported this approach. The final rule allows for this or other alternative approaches to
implement the metals controls. See section V.C.4 of Pan Three of the preamble.

B. How the Standards Work.

       1. Tier HI Standards.  Tier in standards are discussed first because the Agency
believes that the majority of facilities will elect to comply with these standards rather than
56
       EPA notes that permit writers choosing to invoke die omnibus permit authority of
270.32(b)(2) to add conditions to a RCRA permit must show that such conditions are
necessary to ensure protection of human health and die environment and must provide
support for the conditions to interested parties and accept and respond to comment In
addition, permit writers must justify in the administrative record supporting the permit any
decisions based on omnibus authority.
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the Tier I or Tier n screening limits to obtain more flexible permit limits. The Tier m
standards (see 266.106(d)) require: (1) emissions testing to determine actual emissions
taking into account partitioning of metals to combustion gas versus ash or product; and
removal of metals from flue gas by the air pollution control system (APCS); and (2) site-
specific dispersion modeling to take into account actual, predicted dispersion conditions at
the facility.

       To comply with the Tier in standards, predicted ambient concentrations of the
carcinogenic metals, arsenic, beryllium, cadmium, and hexavalent chromium at the
hypothetical maximum exposed individual (MEI) may not result in an increased cancer risk
of more than 1 in 100,000. The risk from each metal must be summed to ensure that the
summed risk does not exceed 1 in 100,000. As proposed, the final rule establishes a risk-
specific dose (RSD) for each metal at the 10~5 (i.e., 1 in 100,000) risk level. If a person is
exposed to the  10~5 RSD (an ambient air concentration) over a lifetime, the probability of
increased cancer incidence is not expected to exceed 1 in 100,000.  To ensure that the
summed risk from the four carcinogens is no greater than 1 in 100,000, the ratios of the
predicted  ambient concentration to the 10"5 RSD must be summed for all metals  to
demonstrate that the sum does not exceed l.O.57

       For the noncarcinogenic metals, antimony, barium, mercury, silver, and thallium,
predicted MEI ambient air concentrations may not exceed the reference air concentrations
(RACs), as proposed.  The RAC for lead is based on 10% of the National Ambient Air
Quality Standard (NAAQS) for lead, as proposed.  One commenter stated that the lead
RAC may be appropriate for facilities in urban areas but that it is not appropriate for rural
areas with low background lead levels. This commenter suggested a waiver of the lead
RAC where a facility can show that measured ambient air lead levels do not exceed the
NAAQS.  Although this approach is reasonable, the final rule does not include a waiver
provision for the lead RAC based on site-specific ambient air monitoring58 because:  (1)
57     TO implement the metals controls, metals feed rates are limited to levels during die
compliance test or trial bum. Thus, if the owner/operator would tike to have the flexibility
to bum wastes with varying (higher) levels of carcinogenic metals, he/she may choose to
develop two or more operating modes with varying feed rates of carcinogenic metals. If
so, a compliance test or trial bum would be required for each mode of operation to
demonstrate that the summed risk from die carcinogenic metals does not exceed 1 in
100,000. Under this approach, the operator is required to identify the mode of operation at
any lime, and to comply with die metal feed rate limits for mat mode of operation.
58     We note, however, that EPA's Guideline on Air Quality Mftdcls a^nws the use of
ambient air monitoring to develop site-specific dispersion models.
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the lead NAAQS may not be protective given that the Agency has been developing for some
time a proposal to lower the NAAQS (perhaps by as much as 50%) based on health effects
data obtained since the NAAQS was established initially (the Agency plans to propose a
lower lead NAAQS in the fall of 1991); (2) the time and cost of conducting ambient
monitoring in confonnance with procedures established by EPA's Office of Air Quality
Planning and Standards (OAQPS) would make this approach impracticable; (3) a waiver
provision would add extra complexity to the rule; and (4) such a waiver could make
eventual further regulation under amended section 112 of the Clean Air Act more likely.

       a.  Emissions Testing.  Stack emissions testing for metals must be conducted in
confonnance with "Methodology for the Determination of Metals Emissions in Exhaust
Gases from Hazardous Waste Incineration'and Similar Combustion Processes" (Multiple
Metals Train) provided in section 3.1 of Methods Manual for Compliance with the BIF
Regulations (incorporated by reference in 260.11).

       b.  Dispersion Modeling. Dispersion modeling must be conducted in confonnance
with EPA's  Guideline on Air Quality  Models (Revised), EPA's "Hazardous Waste
Combustion  Air Quality Screening Procedure" provided in Methods Manual for
Compliance with the BIF Regulations, or  "EPA SCREEN Screening Procedure" as
described in Screening Procedures for Estimating Air Quality Impact of Stationary Sources.
All three documents are incorporated by reference in today's final rule at 260.11. The
Guideline on Air Quality Models is the Agency's primary guide for dispersion modeling.
The "Hazardous Waste Combustion Air Quality Screening Procedure" is included in EPA's
Guidance on Metals an/ft Hydrogen Chloride Controls ffflT H?231^0115 Waste Incinerators.
Draft Final Report, August 1989. The derivation of this procedure, which was developed
specifically for hazardous waste combustion facilities, is also included in that document
The data base used in the derivation is the same as that used for deriving the Tier I and Tier
n screening limits as summarized hi the October 26,1989 supplement to the proposed BIF
rule (54 FR 43752).  Finally, the EPA SCREEN screening procedure has been in general
use since  1988  when it was developed by EPA's Office of Air Quality Planning and
Standards.  It has been used by Regional Offices,  States, and sources for air dispersion
modeling required by EPA air regulations.

       If a user determines that there is an inconsistency between either of the screening
procedures discussed above and EPA's Guideline on Air Quality Models, the Guideline
shall have primacy.
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       c.   GEP Stack Height  As proposed,  stack heights  used to demonstrate
conformance with the final rule may not exceed Good Engineering Practice (GEP) as
defined in 40 CFR Part 51.100(ii).

       d.  MEL As proposed, the hypothetical MEI concentration is the maximumi annual
average ground level concentration at an off-site location.  On-site MEI locations need not
be used to demonstrate conformance with the standards, unless a person resides on-site.

       e.  Bubble Approach for Multiple Stacks. Given that the standards for metals (and
HQ and Cl2) are health risk-based, the final rules are implemented using a limited "bubble"
approach as proposed. Under the limited bubble approach, emissions from all hazardous
waste combustion stacks at a facility subject to metals and chlorine feed rate limits must be
considered in demonstrating conformance with the acceptable ambient levels. This includes
all boilers and industrial furnaces regulated under today's rule, and also those RCRA-
regulated incinerators and thermal treatment units where feed rate or emission limits have
been established for metals, chlorine, HO, or Q2 by EPA.  (The Agency considered
expanding the bubble to consider other stack emissions such as from nonhazardous waste
incinerators or process stacks, but believes that effective implementation  would be difficult
given the different types and levels of regulatory control and procedures applicable to a
variety of stack emission sources.)

       To implement the bubble approach, dispersion modeling must consider emissions
from all regulated stacks (see discussion above) to predict the maximum annual average
off-site ground level (ie., MEI) concentration of each metal. The MEI location will
generally vary for each metal

       2. Tier // Standards. See 266.106(c). The final rule incorporates the Tier n
emission rate screening limits (see Appendix I of the final rule) as presented in die 1989
supplemental notice as a function of terrain adjusted effective stack height, and noncomplex
versus complex terrain and urban versus rural land use in the vicinity of the facility. The
limits were back-calculated from the RACs and 10^ RSDs established by today's rule
using reasonable, worst-case dispersion scenarios. Conformance with the Tier n emission
rate screening limits is demonstrated by emissions testing  (i.e., die facility's  actual
emissions are compared to the maximum allowable screening limits).

       The methodologies for determining terrain adjusted effective stack height and terrain
type are established in 266.106(b)(3) and (4), and the methodology for determining land
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use in the vicinity of the stack axe provided in "Simplified Land Use Classification
Procedures for Compliance with Tier I and Tier D Limits in Appendix VI of Methods
Manual for Compliance with the BIF Regulations (incorporated by reference in today's
rule, see 260.11).

       a. Special Requirements for Carcinogens. We note that the Tier n emission rate
screening limits for the carcinogenic metals arsenic, beryllium, cadmium, hexavalent
chromium, are back-calculated from the  10*5 RSD for each metal. Thus, if the actual
emission rate of one of those metals was at the Tier n screening limit, the resulting risk to
the MEI is estimated to be 1 in 100,000.  Given that the rule requires that the summed risk
for all carcinogenic metals cannot exceed 1 in 100,000, the ratios of the actual emission rate
to the Tier n allowable emission rate for all of the carcinogenic metals must be summed and
the sum cannot exceed 1.0.

       b. Bubble Approach for Multiple Stacks. Although we believe that most facilities
will use Tier m dispersion modeling to demonstrate confonnance with the metals (and HC1
and Cl2) controls when they have multiple stacks to obtain credit for actual dispersion
conditions, Tier n (or Tier I) may be used.  To use the Tier I feed rate limits or Tier n
emissions rate limits for multiple stacks, the owner/operator must conservatively assume
that all hazardous waste is fed to the source with the worst-case stack (i.e., considering
dispersion). The worst-case stack must be determined from the following equation59 as
applied to each stack:
       K = HVT
       where:
          K = a parameter accounting for relative influence of stack height and plume rise;
          H = physical stack height (meters);
          V ^ flow rate (m^/second); and
          T = exhaust temperature (Kelvin).
The stack with the lowest value of K must be used as the worst-case stack.

       c. Facilities Ineligible to Use the Tier n (and Tier I) Screening Limits. The
screening limits were back-calculated from the RACs and 10*5 RSDs established by
today's rule using dispersion modeling scenarios that the Agency considers reasonable,
59     This equation was proposed at 54 FR 43762 (Oct. 26,1989). It is derived from a
similar equation on pp. 2-3 of Screening Procedures for Estimating Air Quality Impact of
Stationary Sources, EPA-450/4-88-010, August 1988.

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worst-case dispersion scenarios. However, dispersion characteristics at a particular facility
may, in fact, provide worse dispersion of emissions than used to calculate the screening
limits. Consequently, die final rule, as discussed in the 1989 supplemental notice,
establishes criteria for facilities mat ate ineligible to use the screening limits. See
|266.107(b)(7).

       3.  Tier I Standards. See 266.106(b). The final rule incorporates the Tier I feed
rate screening limits (see Appendix I to the rule) as presented in the 1989 supplemental
notice as a function of terrain adjusted effective stack height, and noncomplex versus
complex terrain and urban versus rural land use in the vicinity of the facility. Conformance
with the Tier I feed rate screening limits is demonstrated by sampling and analysis of all
feed streams (hazardous waste, other fuels, and raw materials).

       By complying with the conservative Tier I feed rate  screening limits, applicants
burning hazardous waste with very low concentrations of metals would not have to conduct
emissions testing.  The feed rate limits are back-calculated from the emission screening
limits, assuming that all metals present in feedstreams are emitted to the atmosphere. Thus,
no metals are assumed to partition to the bottom ash or product, and no allowance is made
for removal of metals from the stack gas by an air pollution control system. Consequently,
the Tier I feed rate screening limits are equivalent to the Tier n emission rate screening
limits and are provided in the same table in Appendix I to the  rule.  (At proposal, the feed
rate and emission rate screening limits were provided in separate tables because the Agency
presented the limits in different units - Ib/hr (pound per hour) for feed rate limits, and g/s
(grams per  second) for emission rate limits. To avoid confusion and for simplicity,
however, the final role combines the Tier I and H screening limits and presents the limits in
g/hr (grams per hour)).

       The Tier n discussions above on special requirements  for carcinogens also applies
to the Tier I feed rate limits.  Thus, to demonstrate confonnance with the feed rate limits for
the carcinogenic metals, the sum of the ratios of the actual feed rate to the Tier I allowable
feed rate for all of the carcinogenic metals must be summed, and the sum cannot exceed
1.0.

       In addition, the Tier n discussions above on the bubble approach for multiple
stacks and criteria for facilities that are ineligible to use the screening limits apply to die Tier
1 feed rate screening limits as welL
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       Finally, we note that the Tier I feed rate limits may be adjusted upward to reflect
 site-specific dispersion modeling. This is a hybrid of Tiers I and IE. See 266.106(e).
 Under this approach, site-specific dispersion modeling may be conducted using the
 procedures discussed above to back-calculate allowable emission rates for each metal.
 These allowable emission rates then become the adjusted feed rate limits.  Given that
 emissions testing is not conducted under this modified Tier I approach, no credit is given
 for partitioning of metals to bottom ash or product, or removal by the air pollution control
 system.

 C.  Implementation.

       As discussed above, EPA developed a three-tiered standard to ensure that metals
 emissions do not pose an unacceptable risk to human health and the environment Tier I
 consists of conservative feed rate screening limits, Tier n establishes conservative emission
 rate screening limits, and Tier m allows the use of site-specific air dispersion modeling to
 demonstrate compliance. The decision of. which  tier to use depends on the physical
 characteristics of the facility and surrounding terrain, on the anticipated waste compositions
 and feed rates, and on the level of resources available for conducting the analysis.  It is
 acceptable to use different tiers to comply with the standards for different metals.

       1. Tier I Implementation.  The Tier I feed rate limits are implemented by sampling
 and analysis as necessary and flow rate monitoring of each feedstream (i.e., hazardous
 waste, other fuels, and raw materials) to ensure that the total feed rate of each metal does
 not exceed the Tier I limit on either an hourly rolling average or instantaneous basis (i.e., at
 any time), except as provided for the carcinogenic metals and lead as discussed below.

       a.  Special Procedures for Carcinogenic Metals. Given that, for the carcinogenic
 metals, the sum of the ratios of the actual feed rates to the Tier I allowable feed rates cannot
 exceed 1.0, there are no fixed feed rate limits for individual carcinogenic metals. Rather,
the operator must insure that on an hourly rolling  average or instantaneous basis (or as
 allowed below for carcinogenic metals and lead) that the mixture of carcinogenic metals fed
into the BIF does not exceed allowable levels.  To demonstrate conformance with this
 standard, the operator must: (1) know the concentration of metals in each feedstream and
the flow rate of each feedstream; (2) calculate on an hourly rolling average or instantaneous
basis (or as  allowed below for carcinogenic metals and lead) the sum of the ratios of the
actual feed rate to the allowable feed rate; and (3) ensure that the sum of the ratios for all
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carcinogenic metals (on an hourly rolling average or instantaneous basis or as allowed
below) does not exceed 1.0.

       b. Averaging Periods. As discussed in the 1989 supplemental notice, the final rule
provides an alternative averaging period to the hourly rolling average or instantaneous basis
for the carcinogenic metals arsenic, beryllium, cadmium, and chromium, and for lead. For
these metals, an averaging period not to exceed 24 hours (i.e., 24-hour rolling average)
may be used provided that the feed rate at any time (Le., instantaneously) does not exceed
10 times the feed rate on an hourly rolling average basis. The Agency believes that an
averaging period greater man an hourly rolling average is reasonable given that the metals
controls are based on lifetime exposures.  However, the Agency is concerned that
averaging periods greater than 24 hours may be difficult to enforce. A ten-fold higher
emission rate should not pose adverse health effects from short-term exposures for the
carcinogenic metals because the 24-hour rolling average would not exceed the level that.
could pose a 10~5 health risk over a lifetime of exposure and the threshold (Le., noncancer)
health effect would not be likely at exposures only ten times higher than the 10~5 RSD. A
ten-fold higher instantaneous ambient level for lead should not pose adverse health effects
given that the acceptable ambient level for long-term exposure to lead (i.e., the lead RAC)
is based on only 10% of the National Ambient Air Quality Standard.

       We do not believe that a similar approach for the other noncarcinogenic metals
would be appropriate given the uncertainty in the level of protection provided by the long-
term acceptable ambient levels (e.g., the RACs are based on oral RfDs converted 1 to 1 to
inhalation values).

       2. Tier II Implementation. Conformance with the Tier n emission rate screening
limits is based on emissions testing (see section IV.B.I.a) using the Multiple Metals Train
prescribed in Methods Manual for Compliance with the BTF Regulations (incorporated by
reference in 260.1 l(a)). The Tier n emission limits are implemented by permit limits on
the following parameters based on operations during the trial burn:

    Maximum feed rate of each metal in total feedstreams (e.g., hazardous waste, raw
     material, other fuel), except as discussed below;

    Maximum feed rate of each metal in total hazardous waste feedstreams;

     Maximum feed rate of each metal in all pumpable hazardous waste feedstreams;
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    * Maximum feed rate of total hazardous waste and pumpable hazardous waste;

     Maximum feed rate of chlorine in total feedstxeams;

    * Maximum capacity in appropriate units (e.g., total heat input, pounds of steam
     produced, raw material feed rate);

     Maximum temperature at the inlet to the air pollution control system (APCS);

     Maximum combustion chamber temperature; and

    * Key parameters to ensure proper operation of the APCS.

       The approach that must be  used to measure these parameters and the approach to
establish limits on each parameter based on trial bum data is specified in 266.102(e)(6).

       In addition, the permit must specify sampling and analysis procedures for all
feedstreams and all flow rates of  all feedstreams must be continuously monitored and
recorded.

       The final rule establishes limits on these parameters because they can affect metals
emissions. The feed rate of metals in both total  hazardous waste feeds and pumpable
hazardous waste feeds is limited because the physical form of the waste (e.g., solid vs
liquid) can affect the partitioning of the metal between bottom ash (for a boiler) or product
(for a furnace) and combustion gas entering the PM control system.  Metals partition to the
combustion gas more readily when fired in a liquid or pumpable form.

       The rule limits tile metal feed rate from total feedstreams to account for metals in
raw materials and nonhazardous fuels.  When added to the emissions from hazardous
waste, noncarcinogenic metals from these sources can cause the  MEI concentration to
exceed the threshold level for health effects and carcinogenic metals from these sources can
cause the MEI concentration to exceed the incremental lifetime cancer risk limit for the rule
of 1 in 100,000. Thus, there controls ensure that burning hazardous waste does not result
in unacceptable risks.

       The rule limits the chlorine feed rate because chlorine can increase the volatility of
metals, thus increasing the rate  of partitioning to the combustion gas and, in some cases,
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resulting in smaller metal particulates in flue gas that can be more difficult to control with a
PM collection system.

       The rule limits the maximum capacity of the device to ensure that, during the
compliance test (under interim status) or the trial burn (under a Part B permit application)
the device is feeding raw materials  and nonhazardous fuels at a rate that will not be
exceeded after the compliance test or trial burn. Thus, the gas flow rate and paniculate
loading are maximized during the compliance test or trial burn, which tests the ability of the
PM collection system to control metals.

       The rule limits the maximum temperature at the inlet to die PM collection system
because temperature affects the volatility of a metal - some metal species may be partially
(or totally in the case of mercury) in the vapor form at high temperatures at the inlet to the
PM collection system which will reduce the amount of the metal collected. Limiting the
inlet temperature to that occurring during the compliance test or trial burn will ensure that
the temperature cannot be increased later which could result  in an increase in metals
emissions.

       Finally, the rule limits key operating parameters of the PM air pollution control
system to ensure that it continues to operate as efficiently as it did during the compliance
test or trial burn.

       3.  Tier HI Implementation.  Conformance with Tier m is demonstrated by
emissions testing and site-specific dispersion modeling showing that ambient levels  of
metals do not exceed allowable levels.  Permit limits are established for the same
parameters as required for Tier n.

       4.  Special Requirements for Furnaces that Recycle Collected Paniculate Matter.
Metal emissions are not feasibly monitored on a continuous basis.  Thus, some other
means of demonstrating compliance is necessary. For most types of BIFs, compliance is
demonstrated by monitoring feed rates of metals from all feedstreams. EPA requested
comment on whether approaches other than monitoring feed rates of metals may be more
appropriate to implement the metals controls.  See 54 FR 43760 (Oct. 26, 1989).  A
number of commenters argued that the material balance approach for implementing the
metals controls was impractical and nonconservative for cement kilns. The material balance
approach for metals limits the feed rate of each metal in three types of feeds: (1) pumpable
hazardous waste; (2) total hazardous waste; and (3) total feedstreams. Although limiting
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 the feed rate of each metal in the total hazardous waste feed and the pumpable hazardous
 waste feed was workable, commenters argued that limiting the feed rate of metals in total
 feedstreams was unpractical for cement kilns because of the variety of raw materials they
 feed. Raw materials to a cement kiln are a blend of several components  including calcium
 sources such as limestone, sea shells, marl, or chalk, silica sources such as clay, shale,
 slate, or sand, and iron sources such as iron ore or mill grindings. The proportions of the
 components of the blend are changed frequently according to the type of cement desired
 and the composition of die sources.  This can make it very difficult to accurately determine
 die metals feed rate in die blended raw materials.

        Of even more concern to the Agency, however, is the fact that the material balance
 approach is not likely to be conservative (i.e., protective) for furnaces, like cement kilns,
 that recycle collected PM back into the furnace. Because the dust is recycled, an increase in
 the feed rate of a metal in one of the feedstreams - such as spiking during a compliance test
 (under interim status) or a trial burn (under a Pan B permit application) - leads to a gradual
 increase in the concentration (and feed rate) of the metal in the recharged kiln dust which
 leads to a gradual increase hi the metal emissions.  Several recharge cycles may be
 necessary for the kiln to reach steady state condition. Thus, until the system reaches
 equilibrium, metals feed rates do not correlate with metals emissions.

        EPA considered a number of alternatives to address the problem that the recycled
 dust creates a system  that is out of equilibrium when a metal is spiked.  We considered
 handling the recycled dust as another feedstream. Under this approach, the feed rate of
 metals in the recycled dust would be considered along with those from other feedstreams.
 (Or alternatively, the  feed rate of metals in the recycled dust would be considered as a
 fourth level of metals feed rate controls ~ that is, the feed rate of metals in pumpable
 hazardous waste, total hazardous waste, recycled dust, and total feedstreams would be
 limited.) We did not adopt mis approach because:  (1) the recycled dust is an internal
 recycled stream so mat limits on the recycled dust coupled with limits on other feedstreams
 would probably correlate with metals emissions in die kiln off-gas, but not necessarily widi
 stack emissions; and (2) during an emissions test when metals are spiked, the system will
 not be in equilibrium and we do not know enough about metal behavior in die system to
 determine whether die metals feed rate in die dust would be higher or lower after reaching
, equilibrium (Le., we did not know whether this approach would be conservative).

        To address this concern diat die material balance approach to implementing metals
 controls is not likely to be conservative (i.e., protective) for furnaces  that recycle dust,

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 today's rale requires owners and operators of such devices to comply with one of three
 alternatives: (1) daily monitoring of collected PM to ensure mat metals levels do not exceed
 limits that relate concentration of the metal in the collected PM to emitted PM; (2) daily
 stack sampling for metals; or (3) conditioning of the furnace system prior to compliance
 testing to ensure that metals emissions are at equilibrium with metals feed rates.. We
 discuss each of these procedures below.

       We note first, however, that today's rule gives owners and operators the option of
 selecting one of these methods only during interim status.. The Director will determine
 under the Part B permit application proceeding which of these methods (or whether another
 method) may be more appropriate on a case-by-case basis considering the facts. See
 266.106(f). In addition, we note that experience with these methods during interim status
 may indicate the need to refine them for use under a RCRA operating permit Finally, we
 note that this provision of the permit standards is not limited to furnaces that recycle
 collected PM (However, the methods discussed below may be used during interim status
 only by furnaces that recycle collected PM.) The permit standards provide this flexibility
 because, although we believe that these methods (as they may be refined with experience)
 or other methods that adequately address the concerns described below must be required
 for systems that recycle collected PM, the first two methods (i.e., monitoring collected PM
v or daily stack sampling) may be preferable for other types of devices as well.  This is
 because these first two alternative methods address not only the special problem caused by
 recycled PM but also the problem of the difficulty (and imprecision) associated with
 limiting metals emission rates by  the material balance approach given the variability of
 waste and  raw material matrices and variability of the concentrations of metals in
 feedstreams, a problem that also exists for these furnaces and will exist for other devices as
 well.>

       a. Monitoring Metals in Collected PM. This approach will control metals emission
 rates by establishing limits on all of the parameters discussed above for implementing the
 Tier H and Tier in controls, except for limits on the feed rate of each metal in total
 feedstreams. In lieu of that parameter, the final rule limits the concentration of each metal
 in collected PM. See "Alternative Methodology for Implementing Metals Controls " in
 Method Manual for Compliance with the RTF Regulations (incorporated by reference in
 260.11).  The concentration limit is  calculated by determining the roi"iinim allowable
 60     We also note that these methods may be prcferrable to the material balance approach
 in some situations for implementing the metals controls for hazardous waste incinerators.
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concentration of each metal in the emitted PM and by empirically relating the concentration
of the metal in the emitted PM to the concentration of the metal in collected PM (i.e., the
enrichment factor). The maximum allowable concentration of each metal in the emitted PM
is determined by dividing the allowable emission rate for the metal in pounds per hour by
the  applicable  PM standard61  in pounds per hour.  The enrichment factor (i.e.,
concentration of a metal in emitted PM divided by the concentration in collected PM) is
determined initially by a series of 10 emissions tests over a two-week period. Quarterly
testing is required thereafter to determine if the enrichment factor changes substantially. If
so, the series of 10 emissions tests must be conducted again to establish the revised
enrichment factor.

       EPA acknowledges certain potential limitations to this approach: (1) die Agency
has limited data to support the main assumption of this approach ~ that the enrichment
factor will remain constant over the range of normal operating conditions that occur
between the initial series of 10 tests to establish the enrichment factor and the quarterly
confirmation tests; and (2) that a problem with emissions is detected after the fact.
However, we have built into the  approach conservative features that should address
concern about whether the enrichment factor may change over time. First, the approach
assumes that the facility is always operating at its maximum allowable PM emission limit.
Although allowable metal concentrations in collected PM would be higher when the facility
operates at lower PM emission levels, the limits do not change. Thus, for example, for
every 10% the facility operates under its PM standard, the limit on metals concentrations in
collected PM are conservative (lower ^^ necessary) by 10%.  Second, the enrichment
factor is statistically determined based on test data as the lower of: (1) twice the enrichment
factor at the 95% confidence level; or (2) the enrichment factor at the 99% confidence level
Where there is significant scatter  in the data,  twice the enrichment factor at the 95%
confidence level is likely to govern. Thus, when the enrichment factor varies significantly
during the 10 tests, not only is the enrichment factor based on the 95% confidence level,
but an additional margin of safety is provided by doubling the factor at the 95% confidence
level for purposes of determining the metal limit  in collected PM.62
61     The applicable PM standard is 0.08 gr/dscf or any more stringent standard that may
apply under the NSPS or SIP.
&     In addition, the methodology requires that a "safe enrichment factor" of 100 be used
when a metal is at nondetect levels in the collected PM. Mercury, for example, may be at
nondetect levels because it is likely to be in the vapor form (and not collected as PM) in an
ESP or baghouse.
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       As for detection after the fact, sampling of collected dust is required every eight
hours to form a daily composite sample. The operator is allowed up to 48 hours to analyze
the daily composite63 given that the analytical procedures can take 24 to 48 hours even for
on-site laboratories. In addition, if the sample fails the concentration limit for a metal, the
operator may analyze two duplicate samples that he may have elected to obtain to determine
if the failed sample is an outlier.  Analyses of these back-up samples will also take up to 48
hours.  Thus, it could take up to four days to confirm that a dust sample has failed the
concentration limit and that a violation of the metals emissions controls may have
occurred.64

       Notwithstanding this provision of the method, EPA expects that owners  and
operators that want to comply with the spirit of the controls and to operate in a manner that
is protective of human health and  the environment will conduct triplicate analyses of
samples for those metals that may exceed the "conservative" metal limit to avoid the time
delay of subsequently analyzing back-up samples if the initial sample fails the concentration
limit Owners/operators should use historical data to determine whether a metal may be
close to exceeding a concentration  limit and, thus, routinely analyze "back-up" samples
concurrently with the "required" sample for such  metals. Further, EPA expects  that
enforcement officials will consider whether the owner/operator has taken such precautions
to minimize the time during which they may be operating under violation conditions (if the
dust concentration actually exceeds the  "violation" limit) in determining appropriate
enforcement action.
63     Except for "noncritical" metals where 30 continuous days of analyses demonstrate
that the dust concentration for the metal does not exceed 10% of the concentration limit
For these metals, weekly composite samples must be analyzed. If a weekly composite
exceeds 10% of the dust concentration limit, however, daily analyses would be again
required.
64     The methodology requires that two dust concentration limits be established for each
metal: a "conservative" limit and a "violation" limit For example, the conservative limit is
based on the safe enrichment factor of twice the enrichment factor at the upper 95%
confidence level, while the violation limit is based on the enrichment factor at the upper
95% confidence level If the conservative limit is failed more than 3 times out of 60 times,
the owner/operator must notify the Director and he may bum hazardous waste for a total of
720 hours during which: (1) the series of 10 emissions tests must be conducted to revise
the enrichment factor and the dust concentration limits; and (2) the irn*""wm feed rate of
each metal in the hazardous waste is reduced by 50% (except during the three compliance
tests). If the violation limit is exceeded, however, the operator is in violation of the metals
controls (and he must also notify the Director, reduce the feed rate of metals in hazardous
waste, and conduct the series of 10 tests to calculate the revised concentration limits).
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       Notwithstanding these potential limitations, EPA believes that this methodology is
 preferable to the material balance approach. Rather than attempt to limit emissions by
 limiting metal feed rates and  extrapolating through a number of not well-understood
 processes for furnaces that recycle dust, the methodology in the final  rule goes to the
 material that is closest to what is being emitted, collected PM, to extrapolate to emissions.

       Limits on the operating parameters discussed above will be established under this
 methodology during a minimum of three "compliance tests" of the first five of the ten
 emissions tests required to establish the enrichment factor for each metal. Consequently,
 during three of the ten runs, feed rates of metals in total hazardous waste and pumpable
 hazardous waste will be at the maximum level that the  facility may operate during the
 remainder of interim status.  Although the feed rate of metals in the hazardous waste during
 the other tests need not be at the maximum level established during the three "compliance
 tests", the feed rate must be at least 25%65 of the compliance test level, and the facility
 must operate at the compliance test capacity (i.e., the maximum capacity at which the
 facility may operate during the remainder of interim status). The owner and operator must
 demonstrate  compliance with the applicable PM standard and the metals emissions
 standards of 266.106(c) or (d) during all ten tests required to establish enrichment factors.
 The rule requires that the ten emissions tests to determine enrichment factors be conducted
 in a two week period with not more than two tests per day, and that the three compliance
 tests (when metals feed rates from the hazardous waste will be maximized  to establish
 limits for the remainder of interim status) be among the first five tests. EPA is providing
 these restrictions to ensure mat the enrichment factors are representative of operations over
 several  days when operating  conditions can vary, and to  ensure that any effect on
 enrichment factors from the high metals loading from spiked  hazardous waste during the
 three compliance tests will be detected during the subsequent tests.

      The testing and operating requirements for this methodology are prescribed in detail
in "Alternative Methodology for Implementing Metals Controls " in the Methods Manual
We are not requiring the facility operate at the
                                                         (Le., compliance test)
metals feed rate from hazardous waste (or other feedstreams) during all ten emissions tests
because the purpose of the remaining tests is to obtain data to statistically determine the
enrichment factor. Thus, it is important to determine how the enrichment factor may
change as the feed rate of metals from various feedstreams varies. Nonetheless, the metal
feed rate in the hazardous waste must me a minimum of 25% of compliance test limits
during the remaining 7 enrichment factor determination tests.
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      b.  Daily Emissions Testing. Under this option, the owner or operator must
conduct daily emissions testing to  confirm that the metals emissions limits are not
exceeded.  Sampling must be conducted for a minimum of 6 hours each day when
hazardous waste is burned. To ensure that sampled emissions are representative of normal
emissions that day, the testing must be conducted when burning normal hazardous waste
for mat day (i.e., considering metals content, point of introduction into the system, and
physical form of the waste) at normal feed rates for that day and when the air pollution
control system is operated under normal conditions. See 266.103(c)(3)(ii)(B).

      Given that actual emissions sampling is used under this option  to determine
compliance with emission standards, those operating conditions that apply  to other BIFs
after certification of compliance that are designed to control metals emissions are not
necessary.  See 266.103(c)(l).  The operating parameters that need net be limited at
certification of compliance under mis method are:

    Maximum feed rate of each metal in total feedstreams, total hazardous waste
     feedstreams, or pumpable hazardous waste feedstreams;

    Maximum feed rate of pumpable hazardous waste;

    Maximum feed rate of chlorine in total feedstreams;

    Maximum combustion chamber temperature and temperature at the inlet to the air
     pollution control system (APCS); and

    Key parameters to ensure proper operation of the APCS.

      This approach has one drawback - there is a time delay before a violation of the
emissions limits is determined given that it normally takes a week or more to obtain the
results of the stack sampling.  To minimize the impact of this problem, the operator is
required to know the metals concentration and feed rate of hazardous waste at all times and
must determine if a change in metal feed rate from the hazardous waste is likely to result in
exceedance of a metal emission limit

      c. Conditioning Prior to Compliance Testing.   Under this approach  (see
266.103(c)(3)(ii)(Q), the operator must condition the furnace to ensure that metals
emissions are in equilibrium with metals fed into the system from all feedstreams.  The
owner or operator must determine  using engineering judgment when.the system has
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reached equilibrium (Le., how long the system must be conditioned). During conditioning,
hazardous waste and raw materials having the same metals content as will be fed during die
compliance lest must be fed at feed rates that will be fed during the compliance test

       Under this method, limits for all operating parameters under 266.103(c)(l) must
be established during the compliance test

       5. Trial Burns.  A trial burn, or data in lieu of the trial bum (e.g., emissions data
from interim status compliance testing)  is required to demonstrate the performance
capabilities of a system and to establish the operating limits of a facility for the duration of
the operating permit.  Compliance limits will be based on the operating conditions and
emission rates observed during the trial burn. Therefore, to obtain the most flexible
compliance limits, an owner/operator should conduct test burns and the trial burn under
worst-case conditions (those that maximize emissions without exceeding the established
limits). These conditions include feeding the waste used in die trial bum at a feed rate and
metals concentration that reflect the highest levels expected in present or future operations.

       SpUdng with Metals. To achieve the maximum allowable concentrations of metals,
the owner/operator may wish to spike the waste to artificially high concentrations of the
metals during the pre-trial burn period and during the trial burn.  However, the
owner/operator may not feed metals at levels higher than those documented in the Part 8
permit application as  those not likely to result in emissions exceeding allowable levels.
Permit officials will consider this documentation in establishing  pre-trial burn permit
conditions for new permits.

       6. Monitoring and Analysis Requirement.

       a.  Emissions Testing.  Emissions testing and  analysis for metals must be
conducted using "Methodology for the Determination of Metal Emissions in Exhaust Gases
from Hazardous Waste Incineration and Similar Combustion Processes"  provided  in
Methods Manual for Compliance with the BIF Regulations^, incorporated by reference in
260.11. The methodology describes the use of a multiple metals sampling train.  The
methodology also describes and provides references to the appropriate analytical techniques
in Test Methods for Evaluation Solid Wastes fSW-846^. incorporated by reference  in
260.11, that must be used to analyze samples.
66     U.S. EPA, Methods Manual for Compliance with the BIF Regulations. December
1990, EPA/530-SW-91-010. NTIS publication number PB91-120-006.

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      b.  Analysis of Fcedstrcams.  Feedstreams must be analyzed for each of the 10
regulated metals that could reasonably be expected to be in the hazardous waste.  If a
particular metal is excluded from the analysis, the basis for exclusion must be documented
and included in the operating record.  Methods for sampling and analysis of feedstreams
for metals are prescribed in SW-846.

D. Interim Status Compliance Requirements

      As prescribed in 266.103, and discussed in section VII of Pan Three of this
preamble, boilers and industrial furnaces operating under interim status must comply with
the metals emissions standards during interim status.

V. Controls for Emissions  of Hydrogen Chloride and Chlorine Gas

      Today's final rule uses a three-tiered regulatory approach to limit HC1 and C\2
emissions (see 266.107), an approach identical to that used to control noncarcinogenic
toxic metals emissions.

A. Background Information

      In the 1987  proposed rule, EPA stated its intention to develop risk-based HC1
emission standards in the same format and for the same reasons as the proposed metals
emission limits. The HO emission limits for a particular device would have been based on
the device type and capacity, and on the type  of surrounding terrain.   In the 1989
supplemental notice, EPA discussed an alternative approach to make the standards a
function of stack height, terrain, and land use rather than a function of device type and
capacity.  The reasons for the change were the same as those described above in the
discussion of the metals standards.

       Controls on Cl2 were proposed on April 27,1990 (55 FR 17866) because Cl2 can
be emitted from devices burning chlorinated wastes if insufficient hydrogen is available
(i.e., from other hydrocarbon compounds or water vapor) to react with all of the chlorine
present in die waste. In recent tests67 of a cement kiln, EPA found that approximately
50% of gaseous chlorine emissions were in the form of Q2 (and the other 50% was in the
form of HC1).  In the April  1990 proposal, the Agency proposed a Cl2 RAC of 0.4 ug/tn3.
67    u,.s. EPA, Emission Testing of a Precalciner Cqrfiflfl K*Hl at i
November 1990. Document No. EPA/530-SW-9 1-016.
                                                                      Nebraska,
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       In the 1989 supplemental notice, EPA also discussed the possibility of using
continuous HC1 monitors in lieu of the waste feed analysis approach for monitoring HC1
emissions when emissions are likely to be close to allowable emissions.  The Agency
continues to believe mat this is a reasonable approach and believes that it can be effectively
implemented during the permit process as necessary using the omnibus authority.68

B. Response to Comments

       The Agency received a number of comments on the proposed HCl and Q2 controls
as discussed below.

       1. Snon-Term HCl RAC.  A number of commenters stated that the Agency's
support for the proposed 3-minute RAC for HCl was inadequate. The Agency is currently
developing a new methodology for evaluating health effects data to develop a no-adverse-
effect short-term exposure level.69  Given  that the new methodology has not been
approved by die Agency, today's final rule does not establish a short-term RAC for HCl.

       We note that the Tier I chlorine feed rate limits proposed in the 1989 supplemental
notice were based on the short-term HCl RAC because the short-term exposure RAC
provided more restrictive feed rate limits than the long-term RAC. Consequently, the 1989
proposed chlorine feed rate limits are not included in today's final rule. In establishing the
Tier I feed rate limits for chlorine in today's final rule, the Agency considered both the
long-term HCl RAC (i.e.,  7  ug/m3) and the Cl2 RAC (i.e., 0.4  ug/m3), and the
partitioning between the two pollutants in stack gases. Given that the Agency has tested for
Cl2 emissions at only two facilities, and at one of the facilities more than 50% of the
chlorine partitioned to Cl2, the Agency conservatively assumed in calculating feed rate
limits that 100% of the chlorine would be partitioned to Q2- Because the Cl2 RAC is more
than an order of magnitude lower than the HCl RAC, the Tier I chlorine limits were based
on 100% conversion of chlorine to Cl2- If applicants believe mat this  assumption is too
conservative, they may conduct emissions testing to document Cl2 and HCl emission rates.
68     EPA notes that permit writer choosing to invoke the omnibus permit authority of
270.32(b)(2) to add conditions to a RCRA permit must show that such conditions are
necessary to ensure protection of human health and the environment and must provide
support for the conditions to interested parties and accept and respond to comment. In
addition, permit writers must justify in the administrative record supporting the permit any
decisions based on omnibus authority.
69     Memorandum dated September 18 from Susan Griffin, EPA, to Bob Holloway,
EPA, entitled "Derivation of Short-Term RAC for Hd".
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      2. Need for C/2 Controls.  Many commenters stated that Cl2 controls are
unnecessary. One commenter believed that very little hydrogen is needed to react with Cl2
to form HC1. Another commenter believed that operating conditions for boilers and
industrial furnaces are not conducive to the formation of Cl2- Another commenter stated
that the proposed limits to control HC1 emissions will provide adequate control of Cl2
emissions as well.

      The Agency does not agree with these commenters. As discussed above, emissions
testing indicates mat a substantial fraction of gaseous chlorine can be emitted in the form of
Cl2-  In addition, die HC1 controls may not be adequate to control Q2 emissions. Because
Cl2 has a much lower solubility in water than does HC1, the use of wet scrubbers as the
principle emissions control device for HC1 is not likely to significantly reduce emissions of
QI.  Cl2 emissions can be controlled, however, by increasing the hydrogen content of
feed streams (e.g., by adding steam) or by decreasing the feed rate of chlorine. Moreover,
EPA does not believe that high Cl2 emissions relative to HO emissions is a widespread
occurrence.

       3. HCl Emission Test Procedures. A number of commenters who own or operate
cement kilns expressed concern that EPA's HG stack sampling and analysis procedure (see
section 3.3 in Methods Manual for Compliance with  the BIF Regulations^ was
inappropriate because it counted as HCl chlorine in inorganic chloride salts and chloride
ions mat are emitted as ammonium chloride.  The Agency has determined70 that the filter in
the sample probe, in fact, effectively removes fine paniculate chloride salts so mat they do
not interfere with the HCl determination.  The Agency agrees, however, with commenters
that the procedure may consider as HCl chloride  ions that are emitted as  ammonium
chloride.71 Although the Agency has not developed a sampling and analysis procedure
that would correct this problem, we do not believe that any such over-reporting of HCl will
cause a cement kiln to exceed the HCl  standard.  This is because the highly alkaline
particulate matter resulting from the limestone raw materials effectively neutralizes much of
the chlorine generated from hazardous waste fed into the kiln.
     U.S. EPA, Emission Testing of a Precalriner Cement Kiln at Louisville. Nebraska.
November 1990. Document No. EPA/530-SW-91-016.
^1     U.S. EPA, Emissions Testing of a Wet Cement Kiln at Hannibal. MQ. December
1990. Document No. EPA/530-SW-91-017.
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       4. Technology-Based HCl Controls.  Several commenters stated that technology-
 based HC1 emission controls applicable to hazardous waste incinerators (Le., 99%
 reduction of emissions in the stack gas) should also apply to BIFs.  As discussed in the
 proposed rule, the Agency continues to believe that a 99% reduction standard for BIFs to
 control HC1 emissions may be neither technically feasible nor necessary to protect human
 health and the environment The Agency believes that the process chemistry of some
 industrial furnaces (e.g., cement kilns) generally results in low  HC1 emissions and
 concerns about tube corrosion generally limit HC1 concentrations  in boiler emissions.
 Given the low uncontrolled HQ concentrations in many BIFs, a 99% reduction standard in
 addition to the health-based standard required by today's final rule, may not be cost-
 effective. Commenters did not provide data or information that would support the need
 for, and the cost-effectiveness of a technology-based standard in addition to the health-
 based standard provided by the final rule.

       We note that the Agency is currently developing health effects data for two other
 acid gases: hydrogen fluoride and hydrogen bromide.

 C.  Implementation

       Procedures for implementing the HC1 and Cl2 controls are virtually identical to
 those for the metals controls discussed above.

       1. Emissions Testing.  Collection and analysis of HC1 and Cl2 in  stack gas
 emission samples must be conducted according to the procedures prescribed in section 3.3
 of the Methods Manual for Compliance with the B1F Regulations. (Methods Manual)
 incorporated by reference in 260.11. The Methods Manual describes two procedures for
 sampling emissions for HQ and Cl2:  Methods 0050 and 0051. Method 0050 collects a
 sample isokinetically and is, therefore, particularly suited for sampling at sources emitting
 acid paniculate matter (e.g., HQ dissolved in water droplets), such as those controlled by
 wet scrubbers. Method 0051 uses a midget impinger train sampling method designed for
 sampling sources of HQ and Cl2 emissions not in paniculate form. Samples collected
using either method must be analyzed using Method 9057 which is also described in the
Methods Manual

       2. Wastes Analysis.. Methods for sampling and analysis of feedstreams for total
chlorine and chloride are described in detail in SW-846.
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       3.  Interim Status Compliance Requirements. As discussed in section VII of Pan
Three of this preamble, boilers and industrial furnaces operating under interim status must
comply with the HQ and Q2 emissions standards during interim status.

VL   Nontechnical Requirements

       As proposed, die final rule requires BIFs to comply with the nontechnical standards
applicable to other hazardous waste treatment, storage, and disposal facilities. These
nontechnical standards address the potential hazards from spills, fires, explosions, and
unintended egress; require compliance with the manifest system to complete the cradle to
grave tracking system; ensure that hazardous wastes (and hazardous residues) are removed
from the site upon closure; and ensure that the owners and operators are financially capable
of complying with die standards. BIFs burning hazardous waste fuels that operate storage
facilities must already comply with these standards under existing 266.35(c).

       We also note, in particular, that owners and operators of BIFs are subject to the
waste  analysis  requirements  of  264.13  and  265.13  by reference.    See
266.102(a)(2)(ii) for permitted facilities,  and 266.103(a)(4)(ii) for interim status
facilities.  Before a waste is stored or burned, the owner or operator must obtain a detailed
chemical and physical analysis of a representative sample of die waste sufficient to enable
the owner or operator to comply with today's rule.

       The nontechnical standards provided  in today's rule are identical to those that
currently  apply to hazardous waste incinerators. In  today's rule, 266.102(a)(2) applies
these standards to permitted BIFs and 266.103(a)(4) applies these standards to BIFs
operating in interim status.

       Finally, we note that, as proposed, today's rule applies the same controls on
fugitive emissions that currently apply to hazardous waste incinerators. The controls apply
to facilities operating under a permit (see 266.102(7)(i)) and, on the effective date of the
rule, to facilities operating under interim status (see  266.103(h)). The controls provide
for alternative control  strategies including:  (1) keeping the combustion zone where
hazardous waste is burned (or where emissions from such burning may migrate) totally
sealed; and (2) maintaining the combustion zone pressure lower than atmospheric pressure.
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YD.  Interim Status Standards

       In addition to the nontechnical standards discussed above, today's final rule
requires facilities with interim status to comply with substantive emissions controls for
metals, HC1, Cl2, particulates, and CO (and, where applicable, HC and dioxins and
furans). Owners and operators must certify compliance with the emissions controls under
a prescribed schedule, establish limits on prescribed operating parameters, and operate
within those limits throughout interim status.

       Given that interim status requirements are self-implementing, the Agency has
developed comprehensive interim status requirements to ensure that the standards are
implemented effectively. To assist the regulated community in complying with the
requirements, EPA is developing a guidance document entitled Interim Statns Guidance
Document for BIFs (ISGD).  The guidance document will be available shortly after
publication of the final rule in the Federal Register.  The ISGD will  summarize the
provisions of the rule, provide example forms  that may be  used to submit data and
information required by the certifications of precompliance and compliance (see discussions
below), and provide guidance on developing a  compliance test protocol. To provide
further assistance to the regulated community, EPA plans to conduct a series of workshops
open to the public to explain how the interim status standards work. The workshops are
scheduled to begin shortly after publication of the final rule in the Federal Register.  To
obtain a copy of the ISGD or information on the dates and locations of the workshop,
contact the sources identified at the beginning of this preamble under 'TOR FURTHER
INFORMATION CONTACT1.

       The following sections summarize how the interim status standards  work.

A. Certification Schedule.

       1.  Certification of Precompliance. The BIF rule is effective 6 months after the date
of promulgation.  By the effective date, an owner/operator must submit a certification of
precompliance providing prescribed information supporting a determination that emissions
of individual metals, HC1, Q2, and particulates are not likely to exceed allowable levels.
See 266.103(b)(2). For certification of precompliance, the owner/operator must use
engineering judgment to evaluate available information and data (or must use EPA-
prescribed default data provided in sections 8.0 and 9.0 of Methods Manual far
Compliance with the BIF Rf guJatiflPfr incorporated by reference in 266.11) to determine

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that, undo" the operating limits (for EPA-prescribed parameters) that the owner/operator
establishes, emissions are not likely to exceed the allowable emissions provided by
266.105,266.106, and 266.107. The owner and operator must then comply with these
operating conditions (see discussion in section Vn.B below) submitted in the
precompliance certification during the interim status period of operation until a revised
precompliance certification is submitted or until a certification of compliance is submitted as
discussed below.

       In addition, by the effective date of the rule, die owner or operator must submit a
notice for publication in a major local newspaper of general circulation providing die
general facility information prescribed by 266.103(b)(5). The information that must be
provided in the notice includes: the name and address of the owner and operator of the
facility, the type of facility, the type and quantity of hazardous waste burned; the location
where the operating record of the facility can be viewed; a notification that a facility mailing
list is being established so that interested parties may notify the Agency that they wish to be
placed on die mailing list to receive future information and notices about the facility; a brief
summary of the RCRA regulatory system for BIFs; and the address of the EPA Regional
Office where additional information on the RCRA regulatory system may be obtained.
EPA is requiring this public notice to ensure that  the local citizenry is aware that the BIF is
burning hazardous waste and that, to the extent desired, the local citizenry may become
better informed about the facility operations through site inspections and review of data in
the operating record. In turn, this opportunity for local involvement in facility operations
should provide an added incentive for the owner and operator to comply with the spirit and
letter of tile interim status standards.

       EPA notes that facilities that meet the definition of "in existence" of
266.103(a)(l)(ii) but that are not burning hazardous waste on the effective date of the rule
must nonetheless submit a certification of precompliance based on planned operations.  The
certification may be revised at any time in the future if necessary. See 266.103(b)(8).

       2. Certification of Compliance. Within 18 months of promulgation, die
owner/operator must conduct compliance testing72 and submit a certification of compliance
72    We note that compliance testing may be conducted only under operating conditions
for which the facility has submitted a certification of precompliance. This is because die
facility may only operate after the effective date of the rule and prior to submittal of a
certification of compliance under conditions for which it has certified precompliance. If
any applicable emission standard is exceeded during the compliance test (or during
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 with the standards for individual metals (266.106), HC1 and Cl2 (266.107), particulates
 (266.105), and CO, and, where applicable, HC and dioxins/furans (266.104(b) through
 e)).  The certification of compliance is based on emissions testing and establishes operating
 limits for EPA-prescribed parameters based on the compliance test  See 266.103(c)(l).

       If the owner/operator cannot submit the certification of compliance within 18
 months of promulgation, however, he must either (1) notify the Director that he is taking
 an automatic 12-month extension under which hazardous waste burning is limited to a total
 of 720 hours; (2) obtain a case-by-case extension of time for reasons beyond his control; or
 (3) stop burning hazardous waste and begin closure of the hazardous waste portion of the
 facility. See 266.103(c)(6).

       The case-by-case time extension will be provided by the Director if he determines
 that the owner or operator has made a good faith effort to comply with the requirements in a
 timely manner but, for reasons beyond his/her control, are not able to meet the certification
 of compliance deadline. Reasons could include inability to complete modifications to an air
 pollution control system in time to conduct the compliance test to support the certification,
 or a major, unplanned outage of the facility (e.g., need to replace refractory in a kiln) just
 prior to scheduled compliance testing, or as discussed earlier, HC levels attributable to
 organics in raw materials. The Director may use his discretion to determine the length of
 the extension.73 The Director also may impose conditions that ensure that the boiler or
 industrial furnace will be operated in a manner that protects human health and the
 environment, provided that the Director documents the basis for adding such a condition
 and provides the applicant opportunity to comment on it

       In addition, we note that a case-by-case extension may be requested and granted for
 any interim status certification deadline. A case-by-case extension may be granted after an
owner/operator has elected to take the 12-month automatic extension, an extension may be
 granted if the owner/operator cannot comply with the recertification schedule (see
discussion below), and an existing extension may be extended.
f	^ the facility must immediately submit a revised certification of precompliance
establishing revised (ie., more stringent) operating limits.
73     We would not
waste may be burned under a case-by-case extension given that the owner/operator must
support the need for the extension and, if granted, the extension must be for a legitimate
need. In contrast, the hours of burning are limited for the automatic 12-month extension
because mere is no judgement by the Director that, in fact, the extension is warranted.
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       3. Recertification. Owners and operators must periodically conduct compliance
testing and recertify compliance with the standards for individual metals, HC1 and Cl2,
particulates, and CO, and, where applicable, HC and dioxins/furans within three years of
the previous certification while they remain in interim status (i.e., until an operating permit
is issued under 270.66). See266.103(d). EPA is requiring recertifications primarily to
ensure mat air pollution control systems do not deteriorate over time:

       4. Failure to Comply with the Certification Schedule. If the owner or operator
does not comply withe the certification schedule, all hazardous waste burning must cease as
of the date of the missed deadline, and closure must commence. See 266.103(e). Any
burning of hazardous waste by such a device after failure to comply with the certification
schedule must be under a RCRA operating permit  See 270.66.

       To comply with the certification schedule, complete and accurate certifications of
precompliance and compliance must be submitted by the applicable deadlines. (Although
the deadline for certification of compliance may be extended (see 266.103(c)(7)), the
deadline for certification of precompliance may not be extended.) In addition to terminating
interim status if the owner and operator do not comply with the certification schedule, EPA
will also take appropriate enforcement action.

       When closing a BIF, all hazardous waste and hazardous waste residues, including,
but not limited to, ash, scrubber water, and scrubber sludges, must be removed  from the
affected BIF. In addition, the owner/operator must comply with the general interim status
closure requirements of 265.111-265.115, as amended. These requirements, which are
incorporated by reference into  today's rule, specify  closure performance standards;
submission of and compliance with a written closure plan; disposal or decontamination of
equipment, structures, and soils; and certification procedures for closure.

       We note that under amended 265.112(d)(2), for an owner or operator who fails to
submit a complete  certification  of compliance by the applicable compliance  deadline
(including the automatic 12-month extension or the case-by-case extension  under
266.103(c)(6)(i)(B)), the date that he "expects to begin closure" is within 30 days after the
applicable deadline. Therefore, for example, for an owner who takes the automatic 12-
month extension, the closure notification requirements of 265.112(d)(l) or the closure
activity requirements of 265.113 would not be triggered unless and until the owner fails to
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 submit a complete certification of compliance by the 12-month extended deadline and a
 case-by-case extension beyond the 12-month extension was not obtained.

       For any other BIF owner or operator closing during interim status operation (Le.,
 one who closes between the effective date of the rule but before the interim status
 compliance deadline of 18 months after promulgation of the rule, or one who submits a
 complete certification of compliance by the applicable 18-month compliance deadline, the
 12-month automatic extension, or case-by-case extension, and closes during interim
 status), the date when he "expects to begin closure" under 265.112(d)(2) will remain either
 within 30 days after the date on which any hazardous waste management unit receives the
 known final volume of hazardous waste, or if there is a reasonable possibility that the unit
 will receive additional hazardous waste, no later than one year after the date on which the
 unit received the most recent volume of hazardous waste.

       5. Development of the Certification Schedule. In the 1989 supplemental notice, the
 Agency requested comment on alternative schedules for requiring compliance with the
 emissions standards during interim status. The Agency selected a certification deadline of
 18 months (with provision for extensions) because we believe that most facilities will be
 able to install the necessary monitoring equipment, conduct any prccompliance testing mat
 may be necessary, and conduct compliance testing within that time period. Although 18
 months from the date of promulgation is a fairly short period of time, we note that Agency
 staff have made numerous public presentations and have had numerous discussions74 with
 the regulated community, including, in particular, the development of interim status
 compliance procedures.  Thus, facility owners/operators have had some advance indication
 of the general regulatory approach  taken in the final rule.

       The Agency received a comment that the air emission standards for cement kilns
 should be instituted more quickly than the schedule proposed. The commenter believed
 that accelerating the schedule will  not place an excessive burden on these facilities because
 the regulations were proposed far enough in advance for cement kilns to come into
 compliance. The Agency has considered this comment and: (1) sees no compelling reason
 to single out cement kilns from other BIFs for an accelerated schedule; and (2) continues to
 believe that an 18-month compliance period is representative of the time required to
74     See the public docket for this rulemaking for summaries of meetings held with
groups including: Cement Kiln Recycling Coalition, Chemical Manufacturers Association,
National Solid Waste Management Association, Council of Industrial Boiler Operators, and
Hazardous Waste Treatment Council.
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implement necessary plant design or process modifications, install monitoring and
compliance equipment, conduct facility compliance testing, and submit a certification of
compliance testing that documents key operating limits during the remainder of the interim
status period. In fact, the Agency is concerned that in some situations, where, for
example, the air pollution control system may need to be modified, an 18-month deadline
may not provide enough time to complete modifications, "shake-down" the system,
conduct pre-testing75, conduct compliance testing, and analyze test data and submit a
certification of compliance. Thus, the final rule includes provisions for time extensions to
all certification deadlines.

B. Limits on Operating Parameters

       Limits on operating parameters during interim status are established at certification
of precompliance and at certification of compliance following emissions testing 18 months
(unless extended) after promulgation of the rule. The operating conditions can be revised
prior to certification of compliance by submitting a revised certification of precompliance.
The operating conditions can be revised after certification of compliance by conducting
emissions testing and submitting a revised certification of compliance.               '

       After the effective date of the rule and prior to certification of compliance with the
emissions standards based on emissions testing, a facility may operate only under those
conditions for which the facility has submitted a "precompliance" certification
demonstrating that emissions of individual metals, HQ, Q2, and particulates are not likely
                                                                               i
to exceed allowable levels. The operating conditions for which limits are established by
precompliance are (see 266.103(b)(3)):

 .    Feed rate of each of the 10 metals in:
       - Total feed streams, except for furnaces that recycle collected paniculate matter (see
discussion in section VII.I below)
       - Total hazardous waste feed streams
       - Total pumpable hazardous waste feed streams;
     Total feed rate of chlorine in all feed streams;
     Total feed rate of ash in all feed streams, except for cement and light-weight aggregate
     facilities for which ash content of feed streams is not an operating parameter;
 75    Although pretesting is not required, EPA believes that most faculties will conduct
 pretesting before conducting the formal compliance testing with all its attendant QA/QC
 requirements.
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     Total feed rate of hazardous waste and feed rate of pumpable hazardous waste; and
     Maximum capacity in appropriate units such as heat input, steam production, or raw
     material feed rate.

       In addition, the following parameters must be considered in demonstrating
 precompliance and must be continuously monitored (and records maintained in the
 operating log) when monitoring systems are installed (see 266.103(b)(6)):

     Maximum combustion zone temperature;
     Maximum flue gas temperature entering the PM APCS; and
     Limits for APCS-specific operating parameters.

       Once a facility has conducted compliance testing and certified compliance with the
 emissions standards, limits for all of the above parameters, as well as for CO (and, where
 applicable, HQ are established based on the compliance test and remain in force until
 recertification under new conditions. See 266.103(c)(l).

 C. Automatic Waste Feed Cutoff

       Upon certification of compliance, an automatic hazardous waste feed cutoff system
 must engage when the limits (established in the certification) for the following operating
 parameters are exceeded (see 266.103(h)):

   * Total feed rate of hazardous waste and feed rate of pumpable hazardous waste;
                              ;
    Limits on CO and, where applicable, HQ

    Maximum capacity in appropriate units such as heat input, steam production, or raw
     material feed rate;

    Maximum combustion zone temperature;

    Maximum flue gas temperature entering the PM APCS; and

    Limits for APCS-specific operating parameters.

       Facilities operating during interim status after certification of compliance must test
the automatic waste feed shutoff system  once every 7 days to ensure that it is operating
properly, unless an owner/operator can document that weekly testing will result in unsafe
conditions. See 266.103 (k)(iii).  In all cases, testing at least every 30 days is required.
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Owners/operators are required to document the results of these tests and all automatic waste
feed shutoffs that occur during normal operations.

D. Sham Recycling Policy

      The BIF rules supersede the Agency's sham recycling policy (see 48 FR 11157
(March 16,1983)) after the owner or operator certifies during interim status compliance
with the emissions standards for metals, HC1, Q2, particulates, and CO (and, where
applicable, HC and dioxins and furans). Thus, after certification of compliance, a BIF may
burn hazardous waste (other than waste fed solely as an ingredient or solely for material
recovery) with a heating value lower than the 5,000 Btu/lb limit generally considered
heretofore to be the minimum for a legitimate hazardous waste fuel. Although the Agency
considers such burning to be treatment, we believe that conformance with the emissions
standards upon certification of compliance under 266.103(c) will ensure protection of
human health and the environment  (Prior to today's rule, BIFs burning a hazardous waste
that was not considered to be a legitimate fuel were subject to the Subpart O incinerator
standards of Parts 264 and 265, assuming burning was not  for some other legitimate
recycling purpose, such as material recovery.)

      Although we indicated above that a BIF may burn hazardous waste for the purpose
of treatment upon certification of compliance, today's rule allows BIFs to bum such
hazardous waste for a total period of time not to exceed 720 hours prior to certification of
compliance. See 266.103(a)(6).  The rule allows such burning only for purposes of
compliance testing (and pretesting to prepare for compliance testing) to determine that the
device can comply with the emissions standards while burning waste for treatment The
rule limits such burning to a total of 720 hours because we believe that period of time is
adequate to complete any pretesting and compliance testing, and it is the same period of
time that .new BIFs may burn hazardous waste during  the pretrial burn period under
270.66(b)(l).

      The Agency  discussed three options in  the 1989  supplemental notice  for
superseding die sham recycling policy: rescinding  the sham recycling  policy on the
effective date of the final rule; rescinding the sham recycling policy when a facility comes
into compliance with the interim status emission standards; or leaving the sham recycling
policy in effect until a RCRA operating permit is issued.
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       The Agency received comments supporting all three of the options.  Eight
 commenters supported the first option, rescinding the sham recycling policy on die
 effective date of the final rule, because the policy is considered guidance.  Eight
 commenters supported the second option, rescinding the sham recycling policy when
 facilities come into compliance with the interim status  emission standards, because the
 standards are protective of human health and die environment Five commenters supported
 the third option, leaving the sham recycling policy in effect until a facility is issued a RCRA
 operating permit, because the permit writer oversight during the permit process is necessary
 to ensure that a facility complies with the appropriate regulations.

       Hie Agency believes that the procedures required for certification of the interim
 status emissions standards are adequate to ensure effective implementation and enforcement
 of the standards. The only emissions standard applicable to permitted facilities that is not
 required during interim status is the destruction and removal efficiency (DRE) standard
 requiring a trial bum to demonstrate 99.99% DRE. The Agency does not believe that this
 is necessary because emissions testing of boilers and industrial furnaces indicates that
 facilities with CO and HC levels within the limits established by today's rule also are likely
 to achieve 99.99% DRE.

       It should be noted that in rescinding the sham recycling policy for these types of
 regulated boilers and industrial furnaces, the Agency is not altering in any way what
 secondary materials are defined as solid and hazardous wastes when burned for legitimate
 energy recovery.  Thus, all spent materials, sludges, and by-products are solid wastes
 when burned for recovery, as are off-specification commercial chemical products which are
 burned as fuels (or used as a component of fuels) in lieu of their original intended use. See
 261.2(c)(2) and 261.33. (Non-listed hazardous commercial chemical products (i.e.,
 those that exhibit a characteristic but are not listed in 261.33) are likewise solid wastes
 when they are recycled in ways that differ from their normal use. 50 FR at 14219 (April
 11,1985).) With respect to the issue of what constitutes a normal manner of use for an
 off-specification commercial chemical product that has some Btu value, or the issue of
 when such a material is used "in lieu of [its] original intended use" (261.33) and so is a
 solid and hazardous waste, the Agency notes that not every type of burning ostensibly for
energy recovery is considered to qualify. Inappropriate modes of burning thus do not
render such materials non-wastes. For example, if ignitable off-specification natural gas
condensate is burned as a motor fuel, or reactive jet fuel (U 133, hydrazine) is burned as
conventional fuel oil, such materials are solid and hazardous wastes and subject to subtitle

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C controls. This is because the mode of burning is not at all like these materials' original
intended use.
                          s,
E. Submittai of Pan B Applications

      Permit writers will require owners and operators to submit Part B applications for
operating permits on a schedule considering the relative hazard to human health and
environment the facility poses compared to other storage, treatment, and disposal facilities
within the Director's purview.

F. DRE Testing

      As proposed, testing to demonstrate 99.99% destruction and removal efficiency
(DRE) of organic compounds in  the waste is not required under interim status. The
complexity and costs of DRE testing, as well as the substantial interaction needed between
owners/operators and regulatory officials, make such testing impracticable during interim
status. EPA expects that the control requirements for CO and HC will result in low levels
of emissions of organic compounds.

G, Chlorinated Diorins and Furans

      As proposed, hazardous waste containing or derived from any of the following
dioxin-listed wastes cannot be burned in a boiler or industrial furnace operating under
interim status:  EPA Hazardous Waste Nos. F02Q, F021, F022, F023, F026, and F027.
Burning these dioxin-containing wastes during interim status is prohibited because boilers
and industrial furnaces cannot be assumed to achieve the 99.9999 percent DRE required for
these wastes.

      Even though these wastes may not be burned during interim status, chlorinated
dioxins and rurans may be emitted as PICs under certain conditions (i.e., when the PM
control device is  operated  within the temperature range of 45Q-750F, or when HC
concentrations exceed 20 ppmv) as discussed in section TIE of Part Three of the preamble.
EPA believes that the emissions testing and risk assessment requirements of 266.104(e)
can be effectively implemented during interim status without significant EPA interaction.
Thus, the rule requires the owner or operator to certify compliance with those
requirements, as applicable.     ...
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H. Special Requirements for Furnaces

       Today's rale provides special interim status requirements industrial furnaces that
feed hazardous waste, except hazardous waste fed solely as an ingredient76, at locations
other than the "hot" end where the product is discharged and fuels are normally fired to
ensure adequate combustion of hazardous waste prior to conducting a trial burn during the
Part B permit process (see 266.103(a)(5)) as follows:  (1) the combustion gases must
have a minimum temperature of 1800F at the point where the waste is introduced77; (2)
the owner or operator must determine (and include such determination in the operating
record) that there is sufficient oxygen present to combust the waste; (3) the continuous
hydrocarbon monitoring controls provided by 266.104(d) apply; and (4) for cement kilns,
hazardous waste must be fed into the kiln itself;

       EPA established a minimum  temperature of 1800F for the location of hazardous
waste firing and is requiring that the owner/operator demonstrate that adequate oxygen is
present to sustain combustion given that it is generally accepted that organic compounds are
readily destroyed at temperatures above 1800F in the presence of adequate oxygen.  The
demonstration of adequate oxygen is particularly important for cement kilns because they
are operated close to stoichiometric oxygen levels (i.e., with little excess oxygen in the
kiln) to efficiently maintain the high temperatures necessary to calcine and sinter the raw
materials.  Although higher excess  oxygen levels would better ensure more complete
combustion of fuels, operating at higher oxygen levels is less thermally efficient and
reduces the kiln production capacity.
76     Hazardous waste is burned solely as an ingredient if it is burned for neither energy
recovery (i.e., it has a heating value less than 5,000 Btu/lb) nor treatment or destruction
(i.e., it contains a total of less man 500 ppm toxic organic constituents listed in Appendix
Vffl, Part 261).
7?     EPA is aware that cement companies have experimented with feeding containerized
waste into the upper, raw material feed end of the kiln using feed chutes mat propel the
containers down into the kiln before they rupture and expose the waste to the combustion
gas (and begin to release hydrocarbons).  In such a situation, the temperature limit applies
at the point that the waste may begin to release hydrocarbons- the point where the
container impacts me charge bed.  The temperature limit does not apply to the point where
the container is actually charged into the kUn. (If, however, a noncontainerized waste is
fired into the kiln at the upper end, the 1800F temperature limit applies at the location
where the waste exits the firing system.)  Although this discussion pertains to cement kilns,
EPA notes mat the subject requirements apply to any industrial furnace that feeds hazardous
waste at a location other than the "hot" end as described in the text
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      In addition, continuous hydrocarbon (HQ monitoring is required to demonstrate
that HC levels do not exceed the regulatory limit of 20 ppmv on a hourly rolling average
basis (or alternative level established under 266.104(f)) irrespective of whether the CO
level is less than 100 ppmv where HC monitoring is not normally required.  See
266.103(a)(6).  EPA is requiring HC monitoring  because  of the concern that CO
monitoring alone may not be an adequate indicator of good combustion conditions when
hazardous waste is fed at locations other than where (nonhazardous) fuels are normally
fired.  See discussion in Part Two, section ILAAa of this preamble.  Continuous
monitoring of HC and compliance with the applicable operating limit is required upon
certification of compliance (or, for furnaces that feed raw materials containing organic
matter and that receive a time extension to certify compliance, upon receipt of the time
extension78).

      The Agency considered whether the hydrocarbon controls were redundant to the
operating requirements specified above and concluded that HC monitoring is needed to
effectively implement and enforce the controls on organic emissions. Although the
operating requirements alone should be adequate to limit organic emissions, absent HC
monitoring there would be no continuous verification that the operating requirements were,
in fact, adequate and that the owner/operator maintained compliance with the operating
requirements.

      Finally, the rule requires that hazardous waste be fired into a cement kiln itself to
ensure mat the waste is not introduced at a location that may not be conducive  to complete
combustion of the waste.  For example, cement companies have considered burning
hazardous waste in the precalciner of a cement kiln. Although such practices may prove
during the permit process to be acceptable, EPA has not tested emissions from a kiln
burning waste at locations other than in the kiln itself, and  is concerned that complete
combustion of organic constituents may not be ensured. Thus, burning hazardous waste in
a cement kilns precalciner is not allowed during interim status. (This restriction is limited
to cement kilns because mis is the only type of kiln of which the Agency is aware where
hazardous waste may be fired at a location that  is clearly not designed for optimum
combustion conditions.  A cement kiln precalciner is designed primarily to achieve
calcining of raw materials and may not provide adequate combustion of hazardous waste.)
78     We note, as discussed elsewhere in the text, the time extension will be conditional
on, among other things, HC (and CO) levels not exceeding an interim limit established in
the extension.       :,.....,:      .      .
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       The special requirements do  not  apply to hazardous waste  that is burned
, (processed) solely as an ingredient79 because such waste does not contain significant levels
 of hazardous nonmetal constituents (i.e., compounds listed in Appendix VTO, Pan 261)
 and, thus, nonmetal emissions will not pose significant risk to human health and the
 environment (Metal emissions will be adequately controlled by today's rule irrespective if
 where the waste is fed into the system because metals are controlled by a PM control
 device.)  Thus, emissions of nonmetal compounds are not of concern when a waste is
 burned (processed) solely as an ingredient. EPA considers a waste to be burned solely as
 an ingredient in a kiln if if is not burned partially as a fuel or for conventional treatment
 (i.e., destruction).  The Agency considers a waste that is fed to boilers and industrial
 furnaces to be burned at least partially for energy recovery and not as an ingredient if it has
 a heating value of 5,000 Btu/lb or greater, as-generated, and at least partially for treatment
 (i.e., destruction) if it contains more than a total of 500 ppm (by weight) of Appendix Vm,
 Part 261, nonmetal hazardous constituents. See 54 FR at 43731-32 where EPA discussed
 use of a 500 ppm standard for distinguishing between recycling activities tantamount to
 production and those constituting conventional treatment

       The Agency notes in addition that it ordinarily does not consider metal-bearing
 wastes hazardous wastes to be used as ingredients when they are placed in industrial
 furnaces  purportedly to contribute to producing a product. (The use of metal-bearing
 wastes for material recovery is discussed earlier in the preamble, and this discussion does
 not deal with the issue of when such wastes are burned for legitimate material recovery in
 industrial furnaces.) To be considered legitimate use as an ingredient, it would normally
 need to be demonstrated to  EPA (or an authorized State) pursuant to 261.2(f) that the
 hazardous metal constituents  in  the waste  are necessary  for the product (i.e.,  are
 contributing to product quality) and are not present in amounts in excess of those necessary
 to contribute to product quality. See 50 FR at 638 (Jan. 4,1985). This would normally
 require some demonstration that these hazardous metal constituents do not render the
 product unsafe for its intended use.  (The other sham recycling criteria discussed frequently
 by EPA would also have to be satisfied.  See, e.g., 53 FR at 522 (Jan. 8, 1988).  The
 79    Under the RCRA hazardous waste regulatory program, EPA considers a hazardous
 waste to be burned or processed as an ingredient if it is used to produce a product EPA
 considers a hazardous waste to be burned or processed for material recovery if one or more
 constituents of the waste is recovered as a product Nonetheless, the criteria are the same
 for determining when a waste is burned (or processed) as an ingredient or for materials
 recovery versus when it is burned for the partial purpose of energy recovery or
 conventional treatment
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types of uses of hazardous wastes in industrial furnaces to produce waste-derived products
of which the Agency is aware, such as using hazardous wastes to produce aggregate or
cement (the Agency is not actually  aware of cement kilns using hazardous wastes
ostensibly as ingredients, although some facilities have contemplated engaging in the
practice) do not appear to satisfy these criteria.  In addition, the Agency notes the
discussion earlier in this preamble (in the context of hazardous waste used as slurry water)
to the effect that the more common and less valuable the raw material the hazardous waste
is replacing, the more likely the activity is to be some form of surrogate treatment

/. Special Metals Controls for Furnaces that Recycle Collected Paniculate Matter

       For reasons discussed in section V.B.4 of this preamble, the final rule requires
owners and operators of furnaces (e.g., cement kilns, light-weight aggregate kilns with dry
paniculate matter (PM) control systems) that recycle collected PM back into the furnace to
implement the metals emissions controls of 266.106(c) or (d) under one of the three
alternative methods. The discussion in section V.B.4 of the preamble summarizes
procedures for certification of compliance under the methods.   For certification of
precompliance, the standard procedures will be used for both the "daily emissions testing"
option, and the "conditioning prior  to compliance testing" option.  Precompliance
procedures are different, however, for the "monitoring metals in collected PM" method, as
discussed below.

       Under the "monitoring metals in collected PM" method, operating limits will be
established for the all of the parameters listed in section VTLB. above except for the feed
rate limit on each metal in total feedstreams. In lieu of that parameter, the special
procedures limit the concentration of each metal  in collected PM.   See "Alternative
Methodology for Implementing Metals Controls n in Method Manual for Compliance with
the BIF Regulations (incorporated by reference in 266.11).

       For certification of precompliance, the owner/operator must estimate the enrichment
factor for each metal using engineering judgment or EPA prescribed default values.  EPA
default values are 100 for mercury and 10 for all other metals. The enrichment factors are
then used to calculate precompliance dust metal concentration limits using the allowable
emission rate for each metal and the applicable PM standard using the same procedures
applicable for certification of compliance. Daily (or weekly for noncritical metals) analysis
of dust samples is required.  If more than 3  of the previous 60  samples fail, the
owner/operator must notify the Director.  The owner/operator is then allowed to burn
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 hazardous waste for up to 720 hours before a revised certification of precompliance must
 be submitted that revises the estimated enrichment factors and establishes revised
 precompliance dust metals concentration limits. The revised enrichment factors must be
 based on testing or engineering judgment using data or information not considered in the
 original estimate.

 /. Recordkeeping

       Over the period of interim status, facilities will be required to generate and maintain
 data and records designed to demonstrate routine compliance with established limits on
 operating parameters.  These records must be sufficient to allow a RCRA inspector to
 review and evaluate recent and past operation of the facility for compliance purposes.
 Records must be maintained for a period of three years or until an operating permit is
 issued under 270.66, whichever is later.

 Vin.   Implementation of Today's Rule

       There are three types of treatment, storage, and disposal facilities (TSDFs) which
 may be affected by today's rule: (1) facilities which are  subject to  RCRA permit
 requirements for the  first time  as a result of today's rule; (2) facilities which are already
 operating under interim status; and (3) facilities that have been issued a RCRA permit The
 following sections describe the compliance obligations for facilities that have units subject
 to permitting due to today's rule.

A. Newly Regulated Facilities

       Prior to receiving a permit, newly regulated facilities  (i.e., facilities which only
contain the types of units newly regulated by today's final rule) must qualify for interim
 status by the effective date of the rule in order to continue managing hazardous wastes in
units newly regulated by today's rule  To obtain interim status, the eligible facility must
meet three criteria: (1) on the date of promulgation of the BIF rule, the facility must be "in
existence" with respect to hazardous waste burning or processing activities; (2) within 90
days of the date of promulgation, the owner or operator must notify EPA or an authorized
 State (if not previously required to do so) of the facility's hazardous waste burning or
processing activities; and (3) within 180 days of the date of promulgation, the owner or
operator must submit Part A of the permit application.
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       1. Definition of "In Existence".  To meet the definition of an existing facility, the
boiler or industrial furnace must either be in operation burning or processing hazardous
waste on or before the effective date of the rule, or construction of the facility (including the
hazardous waste burning or processing equipment) must have commenced on or before the
effective date of the rule.  See 266.103(a)(l)(ii). A facility has commenced construction if
the owner or operator has obtained the Federal, State, and local approvals or permits
necessary to begin physical construction; and either

    (a) A continuous on-site, physical construction program has begun; or

    (b) The owner or operator has entered into contractural obligations - which cannot be
      cancelled or modified without substantial loss - for physical construction of the
      facility to be completed within a reasonable time.  See 270.2.

       2. Section 3010 Notification. BIF owners and operators burning hazardous waste
fuels have already been required to notify of their hazardous waste fuel activities under
existing 266.35 and need not renotify. (See section 3010(a) which allows EPA to waive
notification if the information is considered unnecessary.) Although today's rule requires
small quantity burners and owners and operators of smelting, melting, and refining
furnaces to notify, this notification is not a section 3010 notice and so is not a prerequisite
to obtaining interim status.

       Facilities which have not submitted a section 3010 notification form to EPA must
do so by finsert date 90 days after publication in the FEDERAL REGISTER!. This is done
by completing a section 3010 notification form and sending it to the appropriate EPA
Regional Office. (See EPA form 8700-12, dated 7/90.  See 55 FR 31389, August 2,1990
for a copy of die form. Notification instructions are set forth in 45 FR 12746.)

       3. Part A Permit Application. Newly regulated facilities must also submit a Part A
permit application to the appropriate EPA Regional Office by Tinsett date fi months after
publication in the FEDERAL REGISTER], which is die effective date of today's rule.  (See
270.70(a) and EPA Form 8700-23, dated 1/90.)

B: Interim Status Facilities

       Interim status facilities that contain units newly regulated by today's rule must file
an  amended Part A permit application under 40 CFR 270.10(g) if they are to continue
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managing hazardous waste in these newly regulated units.  The facilities must file the
necessary amendments to EPA by finsert date 6 months after publication in *hc FPP*^ A?:
REGISTER!, the effective date of the rule, or they will have to cease management of
hazardous waste in these units. In authorized states, the facility should also send a copy of
the submission to die State program.

       Today's rule amends 270.72 to allow interim status facilities to add newly
regulated units as a change in interim status without prior Agency approval. The current
procedures for the addition of new units in 270.72(a)(3) require Agency approval prior to
making the change. Section 270.72(a)(l) allows the addition of newly listed or identified
wastes, and any newly regulated units associated with them, to be added to the Part A
application without prior Agency approval. Today's addition of 270.72(a)(6) extends this
ability to any newly regulated unit Today's rule also eliminates the reconstruction limit for
the addition of newly regulated types of units. (As noted earlier, the Agency proposed this
specific change  for boilers and  industrial furnaces, but realized in the  course of
implementing the proposal that the problem was more endemic and called for a general
solution.) This provision is located in 270.72(b)(7).

       In order to add a unit as a change in interim status under the new 270.72(a)(6), the
owner or operator must file the amended Part A permit application by the effective date of
the rule that subjects the unit to regulation.

       Technical Correction to 270.73(f), (g). In the course of developing today's rule,
the Agency discovered that particular regulatory provisions dealing with loss of interim
status are miscodified. See 270.7 3(f), (g).  We are amending these provisions in
today's notice to match the implementing statutory language. The result will be that neither
boilers nor industrial furnaces, nor other units which achieve interim status after Nov. 7,
1984, are subject to the automatic statutory loss of interim status provisions.

       The 1984 HSWA amendments provided that each facility which achieved interim
status prior to die effective date of the amendments would automatically lose  its interim
status on a specified date, unless by an earlier specified date the facility applied for a final
determination regarding the issuance of  a permit (i.e., submitted Part B of its permit
application). See RCRA sections 3005(c)(2), (e)92). The dates for Pan B submission and
loss of interim status vary according to whether the facility is a land  disposal facility,
incinerator, or other facility.  Id-  Of relevance to today's technical correction, HSWA
provided that interim status for incinerators would terminate five years after the enactment
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of HSWA (i.e., on November 8,1989), unless the Pan B application was submitted within
two years after die enactment (i.e., by November 8,1986); interim status for other non-
land disposal facilities would terminate eight years after the HSWA amendments (i.e.,
November 8,1992) unless the Part B application was submitted within four years (i.e.,
November 8,1988).  See RCRA section 3005(c)(2).

       EPA amended its regulations on July IS, 1985 to incorporate these and other
HSWA changes.  See 50 FR at 28702.  EPA's intention in promulgating these amendments
was simply to reflect the new statutory provisions; for the most part, the Agency simply
codified into the regulations die new HSWA language. M. at 28703. In light of the largely
ministerial nature of the regulations, and in view of the need to move quickly to incorporate
HSWA, EPA published these 1985 regulations without opportunity for public comment
Id,  (The D.C Circuit eventually sustained the legality of these procedures in Uniied.
Technologies Corp. v. EPA. 821 F. 2d at 714 (D.C. Cir.1987).)

       Section 270.73(f), (g) sets forth the dates on which interim status for incinerators
and other non-land disposal facilities terminates if the facilities fail to submit their Pan B
applications. However, in contrast to the HSWA amendments, the sections by their terms
apply to all incinerator and other non-land disposal facilities, instead of being limited only
to those facilities which had obtained interim status on November 8,1984, the date of the
HSWA amendments.  In fact, it is impossible for units newly subject to regulation after the
specified dates for submission of Pan B permit applications (such  as the boilers  and
furnaces regulated by today's rule, or certain facilities newly subject to regulation under the
recent Toxicity Characteristic rule) to comply with the rules as codified. EPA did not
intend for these rules to deviate from statutory language. As the preamble to the 1985
codification regulations stated,  the Agency  simply intended for section 270.73(0, (g) to
reflect the HSWA termination-of-interim status provisions. Id. at 28723.

       The Agency is today making a technical correction to these sections to correct this
mistake, and to avoid the unintended (and possibly illegal) result that large classes of newly
regulated units are ineligible for interim status because they failed to submit Pan B
applications at a time they were unregulated.  EPA is proceeding without proposing the
correction for public comment, and believes that public comment is unnecessary, for the
following reasons: (1) this correction simply conforms  the language of the regulations to
die Agency's original expressed intent in  promulgating die  1985 regulations, which
themselves were validly promulgated without the  opportunity for  comment; (2) this
correction simply conforms die regulations to HSWA's plain language; (3) die amendment
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conforms the regulations to the Agency's actual practice in implementing the regulations
and RCRA 3005(c)(2); (4) the amendment is necessary to avoid rendering units newly
regulated after specified Part B permit application submittal dates from being ineligible for
interim status even though they meet all of the statutory interim status eligibility criteria; and
(5) the amendment can be viewed as an interpretative rule, which does not require prior
notice and public comment.

C. Permitted Facilities

       Some permitted facilities contain boiler and furnace units that are newly subject to
Subtitle C regulation as a result of today's rule. These permitted facilities must therefore
submit permit modifications to EPA Regional offices, and comply with federal permit
modification procedures in order to continue to manage hazardous waste in these units.
The modification will be processed under Federal permit modification procedures rather
than  authorized state  procedures because this rule is promulgated under  HSWA
authority.80  However, because the permit undergoing modification is most likely a jointly
issued EPA-state RCRA permit, a copy of the modification request should  also be
submitted to the state if it is an authorized state.

       1. Amendment to 270.42(g). Today's rule contains a new permit modification
procedure in 270.42 for the addition of any newly regulated waste management units used
to manage hazardous wastes (see 270.42(g)). This two-step procedure essentially allows
the permittee to notify the Agency of its newly regulated boilers and furnaces using the
Class 1 permit  modification procedures, and to continue to handle hazardous wastes.
Subsequently, the permittee must submit a Class 2 or 3 permit modification request to
initiate a permanent change to the permit The self-implementing interim status standards of
266.103 would apply until the permit was modified using the Class 2 or 3 modification
procedures. This new permit modification provision only applies to newly regulated units
that were not previously subject to the permitting requirements of Subtitle C of RCRA.

       Today's new permit modification provision for newly regulated units is essentially
identical to the special procedure in 270.42(g) for newly regulated wastes. The purpose
of today's amendment is to extend the same opportunities and procedures that are available
for newly regulated waste streams (and any units used to manage them) to those situations
u     Except, however, the provisions for sludge dryers, carbon regeneration units,
infrared incinerators, and plasma arc incinerators are not promulgated under HSWA
authority.
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where the unit becomes newly regulated in absence of a new waste identification. (See S3
FR 37922, September 28,1988.) EPA believes that the same rationale applies to newly
regulated types of units, and is therefore clarifying this provision in today's rule.

       Without the procedure in 270.42(g), the facility would need to obtain an approved
permit modification if the facility were to continue managing hazardous wastes past the
effective date of today's rule, which establishes management standards for boilers and
industrial furnaces. If the modifications were not approved within six months, these
facilities would be barred from handling hazardous wastes, disrupting the ongoing
operations of many of these facilities as well as other RCRA facilities that would then need
to manage the wastes. As discussed below, EPA believes that the addition of a boiler or
industrial furnace to a facility's permit is a Class 3 modification.  Because of the time
allowed for preparation of the modification request by the facility and public participation in
the permit modification procedures, the Agency would be unable to review and make a final
determination on the modification request in the six month period.
                                        f
       Today's technical correction rectifies a potential inequity between permitted facilities
and newly regulated facilities. Newly regulated facilities are required only to submit Pan A
of the  permit application, and submit the RCRA section 3010  Notification form, if
necessary, to obtain interim status. Both activities can be easily completed by die effective
date of today's rule, allowing them to continue operations, while permitted facilities, who
have undergone the scrutiny of the permitting process, would likely be barred from doing
so.

       2. Procedures to Modify Permits. Under today's new procedures in 270.42(g), a
unit that is "in existence" as a unit by managing hazardous waste on or before the effective
date of today's rule must submit a Class 1 modification by that date.  Essentially, this
modification is a notification to the Agency that die facility is managing hazardous wastes in
these newly regulated units.  It could consist of a revised Part A application form clearly
indicating all activities that are newly regulated as a result of today's rule. As pan of the
Class 1 procedure, the permittee must also notify the public regarding the modification
within 90 days of submittal to the Agency.

       Next, within 180 days of the effective date, the permittee must submit a Class 2 or
3 modification request to the Agency. It is at this time that die detailed Pan B information
must be submitted. The Agency believes that the Class 3 permit modification procedures
are most likely applicable to the addition of boilers or industrial furnace units. The Class 3
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modification requires an initial public notice by the facility owner of the modification
request, a 60 day public comment period, and an informal meeting between the owner and
die public within the 60 day period. After the end of the 60 day public comment period, the
Agency will develop a draft permit modification, open a second public comment period of
45 days and hold a public hearing. After the public comment period, the Agency will make
a final decision on the modification request

       Today's rule also amends  Appendix I to 270.42 to classify  the  permit
modifications for boilers and industrial furnaces. Section L is revised to include boilers
and industrial furnaces with incinerators, and to specify additional permit conditions to
conform with today's rule (and the conditions added to incinerator permits under the
omnibus authority of 270.32(b)(2).  For more information on these permit modification
procedures, see 53 FR 37912, September 28, 1988.

D. Addition of Storage Units at Direct Transfer Facilities That Obtain Interim Status

       As discussed in section XII.C of Part Three of this preamble, the requirements for
boilers and industrial furnaces are being promulgated under section 3004(q) of RCRA,
which is a HSWA provision. As a result, under section 3006(g), EPA will implement
these requirements in both authorized and unauthorized States until the State is authorized
to implement these requirements in lieu of EPA. Based on comments received during the
rulemaking, EPA is aware that many interim status facilities newly-regulated under this rule
may wish to add storage units to their facilities in the future rather than continue direct
transfer operations (direct firing of the burner from the transport vehicle). Furthermore,
EPA recommends that facilities install tanks and reduce or eliminate direct transfer practices
because of the additional hazards associated with die practice.  As discussed in more detail
below, EPA believes that such units can be added to the facility without awaiting complete
permitting.

       1. Unauthorized States. Facilities that wish to shift to storage from direct transfer
operations and that are located in unauthorized  states, will generally be able to add such
units to the facility as a change in interim status under 40 CFR 270.72(a)(3). In order to
qualify for addition of units under this provision, the facility must: (1) obtain interim status
for the boiler or industrial furnace; and (2) submit a revised Part A application to the EPA
Regional Office prior to adding the storage units with a justification for  the change.
Because EPA strongly encourages the discontinuation  of direct transfer operations at
boilers and industrial furnaces, EPA believes that the addition  of storage units at such
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facilities constitutes a change necessary to meet federal requirements under 40 CFR
270.72(a)(3)(U). The Regional Office must approve the interim status change, unless it is
covered by amended 270.72(a)(6) just discussed. Although 40 CFR 270.72(b) limits the
extent of an addition that can be made during interim status, the addition of associated
storage units under today's rule would be exempt from this limitation pursuant to
270.72(b)(2).

       2.  Authorized States. Interim status facilities located in authorized states that wish
to discontinue direct transfer operations will also generally be able to add such units to the
facility pursuant to 40 CFR 270.72(a)(3). In states which are not authorized to implement
the HSWA storage requirements for boilers and industrial furnaces, the procedure for
adding storage  units at new interim status boilers or industrial furnaces is the same as
described above for facilities located in unauthorized states. Because EPA is implementing
both die rule promulgated today and the associated storage requirements in such states, the
federal rules governing changes in interim status apply to both the boilers and industrial
furnaces and the addition of associated storage facilities.

       In states which have been authorized to implement the HSWA storage requirements
for boilers and industrial furnaces, facilities newly regulated  under today's rule must
comply with the authorized state requirements concerning the addition of associated storage
units. In some cases, the authorized state may require the facility to obtain a permit prior to
constructing or operating such storage units.

E. Compliance with BIF Versus Incinerator Rules.

       Existing rules (see 266.31(c)) require that cement kilns burning hazardous waste
mat are located in urban areas must comply with die hazardous waste incinerator standards.
In addition, existing rules allow owners/operators of any boiler or industrial furnace to
obtain an incinerator permit These provisions exist because the Agency had not yet
established regulatory controls for BIFs. In fact, the statutory provision (Section
3004(q)(2Kc)) requiring mat cement kilns in urban areas be regulated as incinerators states
that the "...regulations remain in effect until the Agency develops substantive standards for
cement kilns burning hazardous waste." Therefore, on the effective date of the BIF rule,
both of these regulatory provisions will be rescinded except as discussed below.

       Commenters questioned what regulations  should more appropriately apply under
three scenarios: (1) if a BIF is operating in interim status under the Subpart O, Pan 265,
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incinerator standards; (2) if a BIF has already been issued an incinerator operating permit
under Subpart O, Part 264; and (3) if a BIF has previously submitted a Part B application
for an incinerator permit and the permit review process has progressed substantially by the
effective date of the BIF rale.  A BIF currently operating under the interim status
incinerator regulations must comply with the BIF regulations on their effective date in lieu
of the incinerator regulations so that it is subject to the more stringent BIF rule. A BIF
currently operating under an  incinerator permit will continue under that permit until it is
reviewed or the permit term otherwise expires.  At that time, the BIF rule will apply.
Although the Agency's general policy  is that BIFs are to be regulated only under the BIF
rules, we believe permit officials should use their discretion to determine whether to grant
exceptions for the third situation  given the protectiveness  of the standards, and the
desirability of avoiding further delay and expense by having to duplicate the permit process
under these BIF rules.  For example,  if a BIF is operating under the incinerator interim
status standards but has submitted Part  B of the incinerator permit and the permit
proceedings have progressed substantially, the Director may continue processing the permit
(and issue it) under the incinerator standards and use omnibus authority81 to add
conditions to the permit as necessary to conform with the BIF rule.

IX.  Permit Procedures

A. Pan B Information

       As proposed on  May 6,  1987 (52 FR 17015),   270.22 provides specific
information requirements for Pan B of the permit application. Paragraph (a) requires a trial
burn to demonstrate conformance with the performance standards of 266.104 through
266.107, except where the trial burn is waived.  Although the regulatory language is
substantively the same as proposed, it has been restructured for clarity, by specifying the
documentation required to support a waiver from each type of trial burn: DRE trial burn,
paniculate matter trial burn, metals trial bum, and HG/Q2 trial burn.

       In addition, the rule specifies under 270.22(a)(6) that owners and operators may
submit data from previous compliance testing of the device, or from testing of similar
81     EPA notes that permit writers choosing to invoke the omnibus permit authority of
270.32(b)(2) to add conditions to a RCRA permit must show that such conditions are
necessary to ensure protection of human health and the environment and must provide
support for die conditions to interested parties and accept and respond to comment In
addition, permit writers must justify in the administrative record supporting the permit any
decisions based on omnibus authority.

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boilers or industrial furnaces burning similar wastes, in lieu of a trial bum provided that the
data is determined adequate and sufficient documentation of similarity is provided

      Paragraphs (b) through (d) were added to 270.22  to provide information
requirements related to other regulatory provisions being promulgated today for boilers and
industrial furnaces.  Paragraph (b) requires information describing the automatic waste feed
cutoff system.  Paragraph (c) requires  owners and operators using direct  transfer
operations to feed hazardous waste  from transport vehicles directly to the boiler or
industrial furnace to submit information supporting conformance with the direct transfer
standards at  266.111.  Under paragraph (d), owners and operators that claim their
residues are excluded from regulation  under  266.112 must submit information adequate
to demonstrate conformance with those provisions.

B. Special Forms of Permits

      As proposed, the final rule adds  270.66 to Subpan F of Part 270.  This section
establishes special forms of permits  (see discussion below) for new boilers and new
industrial furnaces, and sets forth requirements for the various periods of operation under
which a boiler  or industrial furnace operates, depending on. applicable trial bum
requirements.  This section also establishes trial burn procedures. Finally, this section
discusses special procedures for permitting existing facilities. Although these provisions
were described in the preamble to the proposal, at 52 FR 17016, they are described briefly
below, in order to highlight minor changes from the proposed requirements.

       1. Permits for New Boilers and Industrial Furnaces. Paragraph (b) specifies four
operating periods of a permit for a new facility. The provisions have been restructured
from those proposed in recognition of the fact that all boilers and industrial furnaces subject
to a permit must undergo some type of trial burn. Although a facility could conceivably
meet the requirements for a waiver of the DRE trial bum, paniculate matter trial burn,
metals trial burn,  and HCVC12 trial bum, all regulated facilities must demonstrate
conformance with the carbon monoxide, and where applicable, hydrocarbon limits of
266.104.

       In addition, minor revisions to this section have been made to make the permit
process for new boilers and industrial furnaces consistent with the way the hazardous
waste incinerator permitting process is implemented, i.e., one permit with four periods of
operations rather than an individual permit for each period of operation.
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       Thus, the final rule provides for permits addressing four periods of operation for all
boilers and furnaces: the pre-trial bum period, the trial burn period, the post-trial burn
period, and die final permit period.

       Conditions  addressing  compliance with each  performance  standard  (or
corresponding waiver requirement) will be set in the permit for each period of operation.
Applicants must submit a statement with Part B of the permit application that suggests the
conditions necessary to operate in conformance with the performance standards of
266.104 through  266.107.  For those performance standards for which a trial burn is
required, the Director will use his engineering judgment, and consideration of the
applicant's proposal, in setting operating conditions in the permit sufficient to meet the
performance standards. Once the trial burn data are available, they will be used to modify,
if necessary, the final operating conditions in the permit For those performance standards
for which a trial burn demonstration is not required (for example, when the applicant has
chosen to comply with Tier I of the metals limitations under  266.106(b)), appropriate
conditions (in the above example, metals feed rate limits specified under  266.102(e)(4))
will be set for all periods of operation.

       The pre-trial bum period begins with initial introduction of hazardous waste into the
boiler or industrial furnace and extends for the minimnm time required, not to exceed 720
hours of hazardous waste burning, to bring the device to a point of operational readiness to
conduct a trial burn. This period may be extended once by  the Director if good cause is
shown. The  trial burn period covers the period when the trial burn is conducted.  This
period is followed by the post-trial bum period, which extends for the minimum time
necessary to allow analysis, data computation, and submission of the trial burn results and
modification of the permit by the Director if necessary to reflect the trial bum results.  Such
modifications will proceed under the permit modification provisions at  270.42.

       Paragraph (c) specifies information that must  be included in the trial burn plan.
Paragraph (d) establishes trial burn procedures, including criteria for approval of trial bum
plans and requirements for submission of trial bum data.  Paragraph (e) establishes
procedures for selection of POHCs when a DRE trial bum is required. Finally, paragraph
(f) establishes the determinations that the applicant must make based on the trial bum
results  the data, analyses,  and computations that must be submitted to support
conformance with die applicable emissions standards.
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       2. Permit Procedures for Interim Status Facilities. Applicants owning or operating
existing boilers or industrial furnaces will be permitted under  270.66(g). This paragraph
addresses submission of trial bum plans and trial burn data for existing boilers and
furnaces. These provisions differ from the proposal in that they specifically require that the
applicable trial bum data be submitted and considered prior to permit issuance.  This
language conforms with the January 30,1989 change to the hazardous waste incinerator
regulations, promulgated at 54 FR 4286 providing clarification of this point

X.  Exemption of Small Quantity Burners

       Section 3004(q)(2)(B) of RCRA provides EPA with explicit authority to exempt
from regulation facilities that burn small quantities of hazardous wastes if the wastes are
burned at the same facility at which they are generated. The Administrator is to ensure mat
such waste fuels are burned in devices designed and operated in a manner sufficient to
ensure adequate destruction and removal to protect human health and die environment

       The Agency has carefully evaluated the risks posed by small quantity burning and
concluded that a conditional exemption for small quantity burners should be allowed where
hazardous waste combustion poses insignificant risk.  A discussion of the original May
1987 proposal and the subsequent October 1989 proposed revisions is presented below.

       On May 6,1987 (52 FR 17034), the Agency proposed to exempt facilities that bum
small quantities of hazardous waste that they generate on site because even in the absence
of regulatory control, the health risk posed by such burning would not be  significant.
Eligibility for the exemption would have been based on the quantity of waste burned per
month, established as a function of device type and thermal capacity. In order to be
exempt, in addition to restricting the quantity of waste burned, a facility was required to
notify the Regional Administrator that it is a small quantity burner, limit the maximum
instantaneous waste firing rate to 1% of total fuel burned, and refrain from burning acutely
toxic waste containing dioxin.

       On October 26,1989 (54 FR 43730), the Agency proposed several revisions to the
exemption in the 1987 notice. Rather than establish hazardous waste quantity limits as a
function of device type and capacity, EPA proposed quantity limits that vary as a function
of effective  stack height  The  exempt quantities proposed  in October 1989, and
promulgated today, include several changes to the risk  assessment methodology. In
particular, the quantities are based on evaluation of risks from hydrocarbon (HC) emissions
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 instead of a PIC/POHC ratio as originally proposed. This change was made to better
 account for organic emissions from combustion. In addition, the procedures for evaluation
 of facilities with multiple stacks were revised to reduce over-regulation in these situations.

 A. Response to Comments

       Numerous commenters to the 1987 and  1989 proposals objected to the
 conservatism of the calculated quantity limits and/or the 1% limit on hazardous waste
 firing. The commenters stated that the assumptions used in calculating the exempt limits
 are overly conservative, and that the 1% limit on ruing of hazardous waste is based on
 unrealistic and unjustifiable conclusions. The commenters, however, did not provide data
 or analysis to support their arguments that assumptions used in the small quantity burner
 exemption (SQBE) calculations and conditions (including limits on the waste to be burned)
 for exemption eligibility were too restrictive. Absent  technical support for alternate
 approaches, the Agency continues to believe that the approach proposed in October 1989 is
 reasonable and appropriate. In addition, using less conservative assumptions to derive the
 exempt quantities could allow relatively large amounts of hazardous waste to be burned, a
 result somewhat at odds with the statutory language referring to small "quantities" of
 hazardous waste.  See 266.108(a)(2) which limits the maximum hazardous waste firing
 rate at any time to 1% of the total fuel requirements of the device on a volume basis. See
 also 266.108(a)(3) which requires the hazardous waste to have a minimum heating value
 of 5,000 Btu/lb, as-generated, to ensure that the exemption is limited to fuels as intended
 by section 3004(q)(2)(B) and to ensure adequate destruction of toxic organic constituents.

       One commenter requested credit for the presence of air pollution control devices
 (APCDs). The Agency believes that it is not appropriate to allow credit for APCDs
 because, without requirements for and oversight of the operation and maintenance of the
 devices, there is no assurance that collection efficiencies are being met

       Four commenters to the 1987 proposal urged EPA to delete the small quantity
 burner exemption. These commenters were concerned that the large number of boilers and
 industrial furnaces burning hazardous waste that do not have to meet any design
 requirements would have a detrimental effect on human health and the environment. The
 Agency continues to believe that the exemption is protective of human health and the
 environment because it is health-based, incorporating quantity limits and conservative
 assumptions designed to be protective regardless of size and  location of the device, or
conditions of operation.
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       Two commenters stated that the exemption should apply to facilities that generate
hazardous waste at off-site facilities under the same ownership and operational control.
The Agency is concerned, however, that contrary to Congress's intent, this approach could
allow a large quantity generator to distribute their hazardous wastes in small quantities to
TSDFs (including entities that are parent corporations, joint ventures, subsidiaries of the
generator, etc.) that would then burn the wastes without regulation. Consequently, the
final rule limits the exemption to facilities that burn only hazardous waste generated on-site.

       One commenter to the 1987 proposal urged the Agency to clarify that the 1% limit
on the hazardous waste firing is to be applied only to unmixed hazardous waste fuel, not to
a mixture of hazardous and non-hazardous fuel. The Agency acknowledges the ambiguity
in the proposed rule language and intended the  proposal to require that  the quantity
determination take into account only the hazardous waste fuel prior to mixing with a
nonhazardous waste fuel. Today's final rule contains language to that effect and requires
the exempt facility to keep records to document that the quantity of hazardous waste prior to
mixing with a nonhazardous fuel complies with the quantity limitations.

       Six commenters to the 1989 proposal suggested that quantity limits be based on 1%
of the total fuel burned and not the stack height, which relies upon dispersion only. The
Agency, however, continues to believe that terrain-adjusted stack height is the important
criterion, because it is possible that even a 1% limit, with large dispersion and low stack
height, could pose a threat to human health and the environment

B. Basis for Today's Final Rule

       In  order to calculate  allowable exempt quantities under today's  rule, worst-case
dispersion coefficients (based on incinerator modeling), and an HC unit risk factor of 2 x
10~5 m3/ug (based on a 10"5 risk limit) were assumed, as proposed in the October 1989
supplemental notice. Allowable emission rates of hydrocarbons (HCs)  were then back-
calculated as a function of effective stack height, terrain type,  and land use. The
assumption used in this back-calculation was an HC concentration in the stack gas of ISO
ppmv at 99.99% DRE.   Finally, the exempt quantities were calculated using the HC
emission rates  and an empirically-derived ratio of combustion gas volume to mass of
waste. The most conservative allowable emission rates calculated for each stack height
were then  used as the established quantity limits.
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       A detailed description of the methodology used to derive quantity limits for the
exemption is available in the docket for the supplemental notice.

       As mentioned above, the use of effective stack height to determine eligible quantity
limits reflects one of the revisions proposed in the October 26,1989 supplemental notice.
The Agency notes that we have not established separate exempt quantity limits for the
different terrain types and land use classifications. Rather, the revised quantities are based
on assumptions of terrain and land use that result in the lowest (i.e., most conservative)
exempt quantities. We believe that this conservative approach is appropriate given that
there would be no EPA or State agency oversight of an operator's determination of a
facility's terrain and land use classification. Some key assumptions used to arrive at the
quantity limits are described below.

       EPA evaluated the risks posed by emissions of organic compounds, metals, and
hydrogen chloride, the parameters controlled in the substantive regulations promulgated in
today's rule.82 The analysis demonstrates that the risks posed by organic emissions from
waste-as-fuel activities are overwhelmingly dominated by the risks posed by carcinogenic
(as opposed to noncarcinogenic) waste constituents. Accordingly, the initial evaluation
performed in support of the small quantity burner exemption focused exclusively on
carcinogenic risks, on  the assumption that controls ensuring insignificant risks from
organic carcinogenic emissions will ensure protection against non-carcinogenic releases.
This assumption was confirmed by evaluating the potential risks from metals and hydrogen
chloride that would result when those quantities of waste indicated by the risk analysis for
organic carcinogens were burned.

       The risks from burning small quantities  of hazardous waste are  determined
primarily by the following factors:

    Composition of the waste stream being burned;
    Toxicities and concentrations of hazardous constituents in the waste stream;
   * Destruction and removal efficiency achieved by the device;
    Local meteorology, which influences the amount of dispersion of stack emissions;
   Clustering and size of sources; and
    The effective stack height of the device.
82     U.S. EPA, "Analysis for Calculating a d& Minimis Exemption for Burning Small
Quantities of Waste in Combustion Devices", August 1989.
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      The values of these parameters can and do vary widely.  Reasonable, worst-case
assumptions were made for these parameters in the Agency's calculations of exempt
quantities and evaluation of risks. In the risk analysis, EPA assumed an acceptable cancer
risk level of 1.0 x 10"5 to an individual residing for 70 years at the ground level point of
maximum exposure to reasonable, worst-case stack emissions.  Reasonable, worst-case
dispersion coefficients based on effective stack heights were used.  The dispersion
coefficients were those developed in the risk analysis for the proposed amendments to the
hazardous waste incinerator regulations (See 54 FR 43752  and 55 FR  17871).  The
dispersion coefficients differ by terrain type, land use, and effective stack height Separate
calculations were made for noncomplex and complex terrain and urban and rural land use,
resulting in three different sets of quantity eligibility limits for each effective stack height
The rationale for the assumptions used in the risk analysis is discussed below.

       1.  Composition of Hazardous Waste Stream.  Composition data  on hazardous
waste-derived fuels is scarce. Information gathered by the mail questionnaire survey and
other industry contacts indicate that most of the materials burned are organic solvents that
are usually classified  as hazardous based on ignitability and/or toxicity.  The actual
concentrations of carcinogens in wastes burned by 21 facilities during EPA's field testing
program for boilers and industrial furnaces ranged from 0 to 17% with an average of
approximately 4%.

       The quantity of PICs measured in EPA test bums was found to be independent of
specific POHC species and was a function of hydrocarbon (HC) content of the fuel only.
This is supported by comparisons made by MRI of PICs from  hazardous waste and fossil
fuel combustion.  Since it is impossible to differentiate between the PICs  from fuel and
those from hazardous waste during most tests, it was assumed that the boilers in the EPA
test burns were using fuels of 100% HC and all PICs are the result of hazardous waste
burning. Additionally, HC emissions are presumed to be an acceptable measurement of
PICs; historic data indicate that HC measures from 75 to 95% of all PICs emitted.

       The  hazardous waste was assumed to  contain concentrations  of cadmium,
chromium, nickel, and lead  that were obtained from the state sampling  reports of the
Keystone Cement Company.  Arsenic, barium, and mercury concentrations were based on
90th percentile levels from the Engineering Science Background Document
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       2.  Toxicity of Hazardous Constituents. The average unit risk of those PICs that
were identified during EPA trial bums was 1.0 x 10~5 m^/ug. However, it is likely that the
PICs resulting from incineration under the 99% DRE assumption for the small quantity
burner analysis would have a higher toxicity than those measured under the 99.99% DRE
in the EPA boiler tests. EPA therefore estimates the unit risk for total HCs to be 2.0 x lO"5
m^/ug. This corresponds to a carcinogenic potency of Qi* = 0.07 for hydrocarbons (HC).
As explained in the October 1989 notice, this potency factor was used rather than a Qj*
value of 1.0 for products of incomplete combustion as originally proposed in the May 6,
1987 proposed rule because the Agency was concerned about possible nonconservative
features of PIC estimation. (See 54 FR 43730).

       3.  Destruction Efficiency.   The burner destruction efficiency determines the
quantity of unburned hazardous wastes that will be emitted from the stack.  Assumed
values for boiler and furnace performance were selected based upon a review of test data
generated in support of this rule and  based on the professional judgment of Agency staff
members familiar with die destruction and removal efficiencies (DRE) typically achieved by
boilers. It was assumed that, in the worst case, boilers and furnaces would only achieve
99% DRE83 of organic constituents. This represents a very poorly performing combustion
device.  In fact, as explained previously, most boilers and furnaces can be expected to
achieve 99.99% DRE of organic waste constituents even when operated under less than
optimal conditions.

      4.  Assumptions Regarding Metals and Chlorine in Waste Fuels* A similar
reasonable, worst-case analysis was  performed to evaluate the potential risks posed by
emissions of toxic metals (including carcinogens) and hydrogen chloride from small
quantity burners. As a result, it was determined that, at the volume cut-offs specified by
the exemption and the assumed waste concentrations as discussed above, metals emissions
caused by cofiring of hazardous wastes would not pose a significant risk. The analysis
also considered hydrogen chloride emissions assuming a chlorine content of 50% in the
hazardous waste fuel The chlorine content in  actual hazardous wastes seldom exceeds 3%;
however, the highest chlorine content measured in a hazardous waste fuel fired in a boiler
83    We note that we assumed 99% DRE to derive the small quantity burner exempt
quantities rather than the 99.9% that die owner/operator must assume under the low risk
waste exemption of 266.109 because monitoring of CO is not required for the small
quantity burner exemption to ensure mat good combustion conditions are maintained.  CO
monitoring is required under the low risk waiver of the DRE trial burn.

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of which EPA is aware was 43%. Predicted ground level concentrations of Hd also did
not exceed the reference air concentrations.

       The assumptions used to determine the effect of local meteorology/dispersion and
the clustering of sources (stacks at the facility) are discussed in the following section.

C. How the Exemption is Implemented

       1. Use of Terrain-Adjusted Effective Stack Height.  In the 1987 proposal, the
Agency used a set of assumptions about local meteorology, dispersion modeling, terrain
conditions, etc., to determine eligible quantity limitations. As mentioned above, today's
rule uses terrain-adjusted  effective  stack height along with the most conservative
assumptions of terrain and land use to determine quantity limits for exemption eligibility.
See 266.108.

       2. Multiple Stacks.  As explained in the October 1989 notice, in today's final rule
the exempt quantities for a facility with multiple stacks from boilers or industrial furnaces
burning hazardous waste are limited according to the following equation:
        n
      Actual Quantity Bumed/i)
i=l Allowable Quantity Bumed(i)
                                               1.0
       Where:
     N means the number of stacks
    * Actual Quantity Burned, means the waste quantity per month burned in stack "i"
     Allowable Quantity Burned, means the maTinnm allowable exempt quantity for stack
      II Ml
       For example, if a site had two stacks with effective stack heights (ESH) of 30 and
 10 meters, the following equation would hold:
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r
                                                  + JC
                                              140    40
1.0
                        Where:
                      140 and 40 are the exempt quantities from 266.108 for stack heights of 30 and 10
                       meters, respectively
                      X is the waste quantity burned in the device with the 30 meter stack
                      Y is the waste quantity burned in the device with the 10 meter stack

                        In this example, if Y is burning 15 gallons/month, then X could burn no more than
                  87.5 gallons/month.

                  D. Wastes Ineligible for Exemption

                        Boilers and furnaces burning hazardous waste fuels containing or derived from any
                  of the following dioxin-containing hazardous wastes are  not eligible for the exemption:
                  EPA Hazardous  Waste Nos. F020, F021, F022,  F023, F026, and F027.   See
                  266.108(a)(4).  Given the toxicity of these wastes, EPA does not believe it is appropriate
                  to exempt facilities burning them  from regulation. Hazardous waste fuels containing or
                  derived from these dioxin-containing wastes must be burned at a 99.9999% destruction and
                  removal efficiency (ORE). We cannot expect boilers and furnaces to achieve that level of
                  DRE when operating outside of the Agency's regulatory system.

                  . Exemption of Associated Storage

                        Hazardous fuel storage practices prior to burning vary from site to site. Many
                  facilities burning relatively large quantities of hazardous waste fuels hold the fuels in a
                  storage system and then pump the waste fuels through a dedicated line into the combustion
                  zone of the boiler. Other facilities mix hazardous waste fuels with other fuels (typically
                  virgin fuel oil) in a storage/mixing tank prior to burning the blended material These tanks
                  are not feasibly emptied of hazardous waste every 90 days and so are in most cases
                  ineligible for the generator accumulation provisions in 262.34.   -

                        Under today's rule, facilities storing unmixed hazardous waste fuels are responsible
                  for complying with all applicable standards for the storage of the hazardous waste fuel.
                  Owners and operators that are eligible for the small quantity burner exemption and who mix
                  toxic hazardous waste fuels with other fuels would, however, be exempt from the storage
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standards after such mixing, as proposed  See 266.101(c)(2).  The basis for this
exemption is discussed below.

       The Agency is promulgating an exemption for storage of such storage/mixing tanks
(for small quantity burners) in order for the small quantity burner exemption in Section
3004(q)(2)(B) to have practical application.  Congress evidently envisioned a class of
facilities capable of burning small amounts of hazardous wastes safely absent regulation
and viewed such burning as a superior means of managing these small amounts of waste.
Furthermore, assuming that small quantity waste storage is conducted safely, the Agency
assumes mat Congress also envisioned exemption of the storage since permitting storage
would discourage safe on-site burning just as much as regulating the burning itself.

       We believe that storage of small amounts of hazardous wastes mixed with virgin
fuels would pose no significant incremental risks over storage of the virgin fuels. The
monthly volumes of hazardous waste fuel covered by the small quantity burner exemption,
for example, represent less than 1% of the fuel flow rate through these tanks. Under these
circumstances, we think the statutory exemption can reasonably be read to encompass this
limited class of storage practices as well.

       We note further that the Agency is studying other situations where hazardous
waste-containing mixtures may not be appropriately subject to regulation and will consider
whether to issue rules addressing the issue genetically.  It appears to us justifiable to
address the question for the limited class of burning facilities in advance of other types of
situations because Congress has singled out small quantity burning facilities for exemption
where appropriate. We note further that to the extent these small quantity waste-virgin fuel
tanks are underground storage tanks (as defined in section 9001(1)), they would be subject
to regulation under Subtitle I if they contain petroleum.

F. Notification and Recordkeeping Requirements

       As proposed in the October 26,1989 supplemental notice, the final rule requires
(conditionally) exempt small quantity burners to provide a one-time written notification to
EPA (see 266.108(c)) of their status as a small quantity burner and a certification mat they
are in compliance with the requirements of 266.108.  To assist enforcement efforts, the
owner or operator must also indicate in the notification the maximum allowable quantity
that may be burned per month as provided by 266.108(a)(l). In addition, the final rule
requires small quantity burners to keep records to document that they comply with the
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 conditions of the exemption including: quantities of hazardous waste burned per month;
 quantities of hazardous waste and other fuels burned at any time to demonstrate
 conformant with the 1% hazardous waste firing rate limit; and heating value of the
 hazardous waste.

 XI.  Exemption of Low-Risk  Waste from DRE Standard and Particulate
   Matter Emission  Standard

       Hie final rule defines two types of "low-risk" wastes: (1) waste that is low risk
 with respect to feed rate of hazardous (i.e., Appendix VIE, Part 261) nonmetal constituents
 and, thus, is exempt from the requirement to demonstrate 99.99% DRE; and (2) waste that
 is low risk with respect to both nonmetal constituents and metals (i.e., the waste meets the
 Tier I feed rate limits for metals provided by 266.106(b)) and, thus, is exempt from both
 the DRE standard and the 0.08 gr/dscf paniculate standard. See 266.109.

       The following sections explain these exemptions and how they operate.

 A. Exemption from Compliance with the DRE Standard

       In the May 6,1987 proposed rule, the Agency proposed a risk-based, site-specific
 waiver of the DRE trial bum and the flue gas CO limits for facilities burning waste that
 poses insignificant health risks absent those controls (52 FR 17002). Today's final rule
 retains the exemption from the DRE standard, but requires the facility to monitor CO
 continuously and to comply with the Tier I PIC controls of 266.104(b) (i.e., CO cannot
 exceed the 100 ppmv limit on an hourly rolling average basis).

       In the  1987 proposal, EPA explained the basis for the DRE exemption for boilers or
 industrial furnaces that bum low-risk waste (52 FR 17002). After further consideration,
 however, the Agency believes that controls on emissions of PICs are needed. This is
 because  a waste with low levels of toxic organic constituents can nonetheless  pose
 significant health risk if it is burned under  poor combustion  conditions conducive to
 formation of PICs.  Toxic PICs can form from poor combustion of nontoxtc organic
 compounds.

       The final rule does not allow a burner to operate under the alternative CO  limit
provided by 266.104(c), which allows higher CO levels provided that HC levels do not
exceed 20 ppmv, because the Agency believes that only those devices operating under best
demonstrated technology combustion conditions should be granted an exemption from the
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DRE requirement (We note that this is consistent with the CO restriction for the automatic
waiver of the DRE trial burn for boilers operating under the special operating conditions
provided by 266.110.)  Devices operating at CO levels above 100 ppmv on an hourly
rolling average are not operating under best demonstrated technology combustion
conditions even if they can show that hydrocarbon levels do not exceed 20 ppmv (or the
HC limit established under 2666.104(0).  As discussed at proposal (see 54 FR 43723
c.3), die 20 ppmv HC level represents a demarcation between good and poor combustion
conditions. HC levels under best demonstrated technology combustion conditions would
generally be less than 5 ppmv on an hourly rolling average basis.

B. Exemptionjrom Compliance with the Paniculate Standard

       Today's final rule also provides a waiver of the paniculate standard for facilities that
both obtain the DRE standard waiver and meet the Tier I requirements for all metals.
(Because the PM standard guards against risks from both adsorbed organic compounds and
metals, only facilities with waste that is low risk for both organic constituents and metals
are eligible for the PM waiver.)

       The basis for imposing a paniculate standard on boilers and industrial furnaces
firing hazardous waste, as explained in the October 26,1989 supplemental notice (54 FR
43719), is primarily the concern over adsorption of toxic organics and metals onto the
emitted particulates.  Consequently, the Agency  believes that an exemption from the
paniculate standard for boilers and industrial furnaces is appropriate provided that the
facility can demonstrate that emissions of toxic organics and metals do not pose
unacceptable human health risks.

C. Eligibility Requirements

       Three eligibility requirements for the low-risk waste exemption were detailed in the
1987 proposed rule. Many commenters objected to the first of these requirements, that 50
percent of the fuel fired in the boiler or industrial furnace must consist of oil, natural gas,
coal, or other fossil fuels derived from these fuels. These commenters requested that EPA
allow the cofiring of various other fuels, including tall oil, off-specification fuel oils, and
wood chips.

       Although some of these fuels may provide a hot, stable flame that will support good
combustion, die Agency is concerned that others may not In today's rule, the Agency is
requiring for this exemption the same conditions on the primary fuel as required for the
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 special operating requirements for boilers seeking the automatic waiver from a DRE trial
                                                                         >
 burn (see section fl.A.3 of Part Three of this preamble): a minimum of 50% of the fuel
 fired to the boiler must be high quality "primary" fuel consisting of fossil fuels or fuels
 derived from fossil fuels, tall oil, or, if approved by the Director on a case-by-case basis,
 other nonhazardous fuel comparable to fossil fuel, and all such primary fuels must have a
 minimum as-fired heating value of 8,000 Btu/lb.

       The two remaining eligibility requirements, that the hazardous waste must have an
 as-fired heating value of at least 8,000 Btu/lb, and that the waste must be fired into the
 flame zone of the combustion chamber, are being promulgated as proposed in 1987.  The
 reasons for these requirements are the same as discussed in section n.A.3 of Pan Three of
 this preamble in the context of the automatic waiver of the DRE trial bum for boilers.

 D. How the Low-Risk Waste Exemption Works

       1. Constituents of Concern. The low-risk waste exemption is intended to exempt a
 waste  from either or both the  DRE standard and the paniculate standard if  the
 owner/operator demonstrates that, absent regulatory controls (i.e., under a reasonable,
 worst-case emissions scenario), emissions from the facility will not result in ambient levels
 of toxic organic compounds and/or metals that exceed acceptable levels. The organic
 constituents of concern are the hazardous organic compounds listed in Appendix Vm of 40
 CFR Part 261 and the metals of concern are the 10 regulated metals. See section E of this
 preamble.

       2. Estimation of Worst-Case Emissions. The requirements for estimating worst-
 case emissions were discussed in the May 1987 proposed rule and are being promulgated
 in today's rule with slight modifications.

       To estimate reasonable, worst-case emissions of toxic organic constituents in
 hazardous waste fuel, an owner or operator must: (1) identify every nonmetal Appendix
 Vm constituent that could reasonably be expected to be found in the waste; and (2) assume
 a reasonable, worst-case destruction and removal efficiency (DRE) for each constituent of
99.9 percent in calculating the worst-case emissions (by considering waste concentration
 and feed rate) from the stack for each constituent This assumed DRE of 99.9 percent is
less conservative than the proposed 99 percent assumption in the 1987 notice. The Agency
is making this change in response to the many commenters who objected to the 99 percent
DRE assumption.  Specifically, the commenters' objection was that 99.9 percent was the
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worst DRE measured by die Agency in its nonsteady-state testing of boilers operated under
intentionally upset (Le.,  high CO and smoke) conditions.  The Agency believes that
changing the assumed DRE from 99 percent to 99.9 percent is justified because today's
rule, unlike the 1987 proposal, does not provide a waiver of the continuous CO emission
monitoring (CEM) requirements.  Compliance with  continuous CO monitoring
requirements will ensure that these devices do not operate under upset conditions and will
achieve a DRE of at least  99.9 percent

       The Agency has eliminated the proposed requirement that emissions of products of
incomplete combustion (PICs) be estimated using a ratio of PICs to principal organic
hazardous constituents (POHCs). As explained in the April 1989 notice (54 FR 43730),
use of the PIC:POHC ratio may  not be a conservative method for estimating PIC
emissions.

       An estimate of worst-case emissions is not necessary for metals. To be eligible for
the exemption from the paniculate standard, the waste must be low-risk with respect to
organic compounds and must meet the Tier I metals feed rate limits.  See 266.106(b).
Those metals feed rate limits assume that all metals fed into the device are emitted.

       3. Dispersion Modeling.  Dispersion modeling must be used to predict the
maximum annual average ground level concentration of each toxic nonmetal compound in
the waste using procedures identical to those required to  implement  the Tier HI metals
controls. See266.109(a)(2)(iii)(A).

       4. Acceptable Ambient Levels. Predicted maximum annual average ground level
concentrations of each toxic nonmetal compound may not exceed  levels the Agency
proposed as acceptable for purposes of this rule. The acceptable ambient concentrations
were developed for carcinogenic and noncarcinogenic compounds using the same
procedures used to develop the RACs and 10"5 RSDs for the 10 toxic metals.

       To demonstrate that me noncarcinogenic nonmetal  compounds listed in Appendix
IV of the rule  do not pose an unacceptable health risk, the predicted ground  level
concentrations cannot exceed the levels established in that Appendix.

       To demonstrate that the carcinogenic nonmetal compounds listed in Appendix V of
the rule do not pose an unacceptable health risk, the sum of the ratios of the predicted
ground level concentrations to the levels established in the Appendix cannot exceed 1.0.
This is because the acceptable ambient levels established in Appendix V are based on a 10~5
                                                              f

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 risk level. To ensure that the summed risk from all carcinogenic compounds does not
 exceed 10*5 (i.e., 1 in 100,000), the sum of the ratios described above must be used.

       To demonstrate mat other compounds for which the Agency does not have adequate
 health effects data to establish an acceptable ambient level are not likely to pose a health
 risk, the predicted ambient level cannot exceed 0.09 ug/nA  This is the 5th percentile
 lowest reference air concentration for the compounds listed in Appendix IV of the rule.

       5. Constituents with Inadequate Health Effects Data.  At the time of the 1987
 proposal, die Agency had data adequate for establishing RACs and RSDs for only about
 ISO of the over 400 compounds listed in Appendix Vffl, Pan 261. In the preamble to the
 May 1987 proposal, EPA stated that, to be eligible for the exemption, health effects data
 (i.e., RACs and RSDs) must be available for each constituent in the waste. In response to
 comments concerning the inadequacy of current health effects data to establish a RAC or
 RsD for a large number of compounds, we have established in today's rule a conservative
 RAC value for such constituents determined as the 5th percentile lowest RAC for all of the
 nonmetal Appendix vm, Part 261, constituents - 0.09 ug/m3 (see note to Appendix V of
 the final rule). EPA believes that this approach will be protective of human health and the
 environment and will not unreasonably restrict owners/operators from eligibility for the
 exemption.

 XII.   Storage Standards

A. Permit Standards for Storage

       Under the administrative controls for hazardous waste marketers, burners, and
blenders of hazardous waste burned in boilers and industrial furnaces promulgated on
November 29,1985, and codified in Subpart D of Part 266, EPA subjected existing burner
storage facilities (effective May 29,1986) to only the interim status standards of Part  265.
The permit standards of Part 264 were not applied to existing storage facilities in order to
avoid two-stage permitting, given that today's rule for permitting boiler and industrial
furnace facilities  was under development at that time. The Agency wanted to avoid
requiring a boiler or industrial furnace owner or operator to obtain a permit for their
hazardous waste fuel storage facility and to soon thereafter obtain another permit for
operation of the boiler or industrial furnace under today's rule.

       Today's rule does, therefore, subject such existing burner storage facilities to the
permit standards of Part 264.  See 266.101 (c).

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      Numerous comments on the May 6,1987 proposed rule to subject burner storage
units to the permit standards of Pan 264 agreed that the interim status standards currently in
force are not adequate and permit standards are needed.  Several commenters were
concerned about the potential mishandling of waste fuels stored on-site in and around
residential areas. One commenter requested that prebum transport and storage regulations
for hazardous waste apply to all hazardous waste blends, mixtures, or diluted hazardous
materials.

      With the promulgation of today's rule, all hazardous waste storage units will be
subject to applicable Part 264 and 265 standards. Since hazardous waste storage units
standards are designed to be protective of human health and the environment regardless of
the location of the facility, on-site storage associated with boilers and industrial furnaces
burning hazardous waste is not restricted to areas in or around residential areas. These
standards apply to the storage of any hazardous waste blends, mixtures, or dilutions that
will be burned at these facilities, due to the "mixture rule"  of 40 CFR 261.3.  Whereas
nonindustrial boilers were previously prohibited from burning hazardous wastes unless
they were operated in conformance with the incinerator standards of Subpart O of Parts 264
or 265, today's rule eliminates the distinction between industrial and nonindustrial boilers.
Consequently, today's rule establishes standards that are protective when hazardous waste
is burned in any boiler.

       One commenter recommended  that the final rule  allow the 90-day  "on-site"
accumulation provision to include wastes received at the BIF from off-site, company-
owned locations. The  90-day accumulation provision referred to by the commenter is
contained in 40 CFR 262.34(a) and only applies to generators of hazardous wastes. The
Agency does not intend to apply this provision to hazardous waste treatment, storage, or
disposal facilities.

B. Consideration of Requirement for Liquid Waste Fuel Blending Tanks

       In the October 26,1989 supplemental notice, the Agency requested comment on a
requirement that all boiler and industrial furnaces use blending and surge storage tanks
(i.e., other than other modes of waste fuel transfer) to avoid flow interruptions and waste
stratification which could affect the ability of a combustion device to meet performance
standards. The majority of commenters opposed requiring blending and surge storage
tanks for  BIFs and suggested that such a requirement would not be necessary to ensure
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compliance with performance standards. Several commenters believed that a uniform
requirement for tanks, containers, and/or surge tanks may not be universally appropriate.
These commenters noted that some secondary materials such as lead acid batteries, flue
dust, and various scraps and slags cannot be transferred to  furnaces from a tank or
container system. Another commenter suggested that in some instances, such as feeding
incompatible wastes, direct transfer may be preferable due to health and safety concerns. A
few commenters concurred with this view, but felt that storage and blending tanks should
be required in all other instances. One commenter suggested that storage tanks should be
required only if transport vehicles do not meet Department of Transportation requirements,
secondary containment is not used in transfer operations, and if operations are not covered
by site-specific  contingency or SPCC plans. One commenter agreed that hazardous wastes
should generally be fed from storage tanks and supported a final rule that would allow a
"window of opportunity" to install storage tanks, thus providing an incentive  for a
company to reduce their reliance on direct burning from transport vehicles.

       In today's rule, the Agency is not requiring storage and blending tanks for boilers
and industrial furnaces burning hazardous waste because we continue to believe that such
tanks are not requisite to demonstrating confonnance with the emission standards of
266.104 through  266.107.  However, as indicated in the supplement to the proposed
rule, EPA believes that facilities that install blending and storage tanks may be better able to
control flow interruptions and waste stratification.  Consequently, boilers and industrial
furnaces with blending and/or storage tanks may operate with greater efficiency and thereby
may more readily meet performance standards for emissions.

       We also note that, once an owner/operator is in interim status, the Part A application
may be revised to convert from direct transfer operations to the use of storage units.. See
discussion in section Vin of Part Three of the preamble.

C. Standards for Direct Transfer Operations

       In the October 26, 1989, supplement to the proposed rule, EPA identified
permitting authorities1 concerns about the practice of feeding hazardous waste fuels directly
from transport vehicles to boilers and industrial furnaces. These concerns included: (l)the
potential for fires, explosions, and  spills during transfer  operations; and (2) the
stratification of waste in the transport  container and the potential for waste fuel flow
interruptions which, in turn, could affect the ability of the burner to consistently provide
efficient combustion of the waste. EPA requested comment on two approaches to regulate
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direct transfer operations.  One approach was for permit writers to use the RCRA omnibus
authority to establish .additional permit conditions as necessary to ensure adequate
protection of human health and the environment from such operations The other approach
was to require that facilities burning hazardous waste use blending and surge storage tanks
to avoid die flow interruptions and waste stratification, which would address permit
writers' concerns.

       In the April 27,1990 Federal Register notice, EPA noted that commenters on the
October 1989 notice stated that controls on transfer operations were needed during interim
status.  As a result, the Agency requested comment on the need and appropriateness of
regulating direct transfer operations under interim status standards for containers and tank
systems of Subparts I and J of Pan 265. EPA received numerous comments in response to
these solicitations. The majority of commenters recommended that EPA allow direct
transfer with proper controls and restrictions,  such as: (1) allow direct transfer approval
for facilities granted interim status or a RCRA operating permit; (2) establish direct transfer
standards similar to Subparts I and I of 40 CFR Part 265 for facilities with a contingency
or SPCC plan; and (3) allow direct transfer during test bums alone.  Some respondents
suggested mat instead of allowing direct transfer, EPA should require storage and blending
tanks for all facilities burning hazardous waste.

       The Agency is today promulgating standards regulating direct transfer operations.
See 266.111. The Agency believes that these standards will adequately address potential
risks to human health and the environment.

       EPA considers direct transfer operations to be a part of the hazardous waste firing
system, not a storage activity. Hence, facilities that are not subject to the burner standards
of 266.102 (permit standards) or 266.103 (interim status standards) are not subject to the
direct transfer standards. Examples of facilities not subject to the direct transfer standards
are small quantity burners exempt from regulation under 266.108, metals reclamation
furnaces deferred under 266.100(c), and coke ovens exempt under 266.101(b)(4).

       These direct  transfer standards reference extensively the Subpart I container
standards and the Subpart J tank standards of Parts 264 and 265 and will apply equally to
facilities operating under a permit as well  as those operating under interim status. The
regulations address the area in which transport vehicles are located and piping and other
ancillary equipment  (termed "direct transfer equipment in today's rule) used to transfer
waste from the vehicle to the burner.  The standards provide general operating requirements
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 and controls on equipment integrity, containment and detection of releases, response to
 leaks or spills, design and installation of new direct transfer equipment, and closure.

       1. General Operating Requirements. Facilities that directly transfer hazardous
 waste to boilers and industrial furnaces from transport vehicles must comply with general
 operating requirements that specify safe management practices for handling incompatible
 wastes, spill prevention controls, and automatic waste feed cutoffs.  These general
 operating requirements apply to both containerized and bulk hazardous waste. General
 performance standards for safe operation in today's rule include measures for conducting
 direct transfer operations such that fire, explosion, violent reactions, and other conditions
 that could threaten human health or the environment do not occur. Direct transfer from
 open-top containers is prohibited. Direct transfer equipment, which is any device that
 distributes, meters, or controls hazardous waste flow between a transport vehicle and a
 BIF, must also be closed except when necessary to add  or remove the waste.  Safe
 management practices for handling incompatible wastes are also required. Transport
 vehicles or direct transfer equipment holding ignitable or reactive hazardous waste must be
 located at least 50 feet from the receiving facility's property line.

       2. Inspections and Recordkeeping.  All equipment and areas where direct transfer
 occurs must be inspected hourly for leaks during direct  transfer operations. Control
 equipment, direct  transfer equipment monitoring  data,  and  other equipment ensuring
 compliance with direct transfer standards must also be inspected hourly. Finally, the rule
 provides recordkeeping requirements to document results of inspections.

       We note that only daily inspection is required under Subpart I of Parts 264 and 265
 for tank systems (i.e., piping, valves and other direct transfer equipment).  EPA is
requiring hourly inspections of direct transfer operations because, unlike tank systems that
 use hard piping, direct transfer operations use flexible hoses and quick change coupling
 devices ttiat have a greater potential for leaks or spills.

       3. Equipment Integrity. Equipment integrity requirements address direct transfer
equipment (e.g., piping or conveyors from the transport vehicle to the burner).  The
standards promulgated today require the transfer of waste to other equipment if equipment
holding hazardous waste leaks or is in poor condition, and specify safe management
practices for transferring wastes to other containers or transport vehicles. An assessment is
required of existing direct transfer equipment that does not meet the secondary containment
requirements discussed below to determine if the direct transfer equipment is leaking or
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unfit for use and must be certified by a qualified, registered professional engineer.  If
equipment is found to be leaking or unfit for use, the owner/operator must comply with the
requirements addressing responses to leaks or spills.

       4. Containment and Detection of Releases.  The  rule requires secondary
containment for underground direct transfer equipment. See 266.11 l(e)(l). Inspections
and leak tests of direct transfer equipment and recordkeeping requirements are also
required.  Existing direct transfer equipment subject to the secondary containment
requirements of 265.193 (by reference in 266.1 ll(e)(l) of today's rule) must comply
with those secondary containment requirements within two years after the effective date of
the rule. EPA believes that two years (30 months from promulgation) is a reasonable
amount of time to  enable owners and operators  to retrofit  existing equipment with
secondary containment as necessary given that direct transfer operations generally do not
involve die use of extensive equipment subject to secondary containment

       5. Response to Leaks or Spills. Action required to be followed in the event of a
leak or spill are based on those required in Subpart J, Part 26S.  See 266.111(e)(5).
Should a leak or spill occur, equipment use must cease (to prevent the flow or addition of
wastes into the direct transfer equipment or secondary containment system) and the system
must be inspected to determine the cause of the release.  The waste must be removed from
the direct transfer equipment or secondary containment system and visible releases to the
environment must be contained.  In the event of a leak or spill, the Director must be notified
of the incident in writing.  Secondary containment repair, or closure of the leaking
equipment and certification of major repairs must be provided

       6. Design and Installation of New Equipment. New direct transfer equipment must
meet the design and installation standards specified in today's rule as defined in 265.192
for tank systems.  See 266.1 ll(e)(4) in  today's rule referencing that section.  The
standards include: specifications for assessing the design of new direct transfer equipment;
backfill requirements for new  underground direct transfer equipment; tightness tests;
equipment support and  protection requirements; corrosion protection;  and written
certification that these requirements have been met

       7. Closure. Today's rule applies by reference the closure requirements for direct
transfer equipment provided by 265.197 (except paragraphs (c)(2) through (c)(4)). See
266.1 ll(eX6). That section requires the removal or decontamination of waste residues,
system components, and contaminated soils, structures, and equipment
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 Xm.  Applicability of  the Bevill  Exclusion  to  Combustion Residues When
      Burning Hazardous Waste

       Under the Agency's existing regulations, wastes that are derived from the treatment
 of listed hazardous wastes are also considered to be hazardous unless and until they are
 delisted (see 40 CFR 261.3(c)(2) and (d)(2)). The combustion or processing of hazardous
 waste in a device  that uses elevated temperatures as the primary means to change the
 chemical, physical, or biological character or composition of the hazardous waste, is a type
 of treatment no matter what type of device is used in the process, or for what purpose the
 waste is burned or processed.  Accordingly, under the Agency's existing rules, residues
 from thermal combustion (or processing) of listed hazardous  wastes remain the listed
 hazardous wastes until they are delisted.                    

       When the device burning hazardous waste is (1) a boiler burning primarily coal or
 other fossil fuels, (2) an industrial furnace processing primarily ores or minerals, or (3) a
 cement kiln processing primarily raw materials, the applicability of the Bevill exclusion
 must be considered (see RCRA Section 3001(b)(3)(A)(i-iii)). The Bevill exclusion refers
 to residues resulting from burning or processing certain materials whereby the residues are
 not considered to be hazardous waste at this time because they require special study to
 determine whether  they should be regulated under Subtitle C.

       To determine whether the Bevill exclusion continues to apply when the devices
 described above burn or process hazardous waste, today's final rule promulgates the case-
 by-case determination involving a two-part test as discussed in the October 1989
 supplement to the  proposed rule. See 266.112. Under this test, owners and operators
 must determine on  a site-specific basis whether the co-combustion of hazardous waste has
 significantly affected the character of the residue. The residue is considered to  be
 significantly affected if both:  (1) concentrations of toxic (Appendix VIH, Part 261)
 compounds in the waste-derived residue are significantly higher than in normal (i.e.,
 without bunungfcrocessing hazardous waste) residue; and (2) toxic compounds are present
 in the waste-derived residue at levels that could pose significant risk to human health. If
 the case-by-case determination demonstrates that die residue has been significantly affected
 (or if the owner or operator does not obtain data and information adequate to support a
 demonstration that the residue has not  been significantly affected), such derived-from
residues are subject to regulation as hazardous waste because the  residues are no longer the
type of material Congress  commanded the Agency to study before regulation. Such
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residues ait no longer deemed to be from processing ores or minerals, burning fossil fuels,
or making cement.  Rather, they are from treating hazardous waste.

       The following sections discuss the basis for applying the Bevill exclusion to
derived-from residues, the evolution of the Agency's interpretations on the applicability of
the Bevill exclusion to waste-derived residues, and how today's case-by-case determination
works.

A. Basis for Applying the Bevill Exclusion to Derived-Prom Residues

       A number of commenters questioned whether the Agency has the legal authority to
determine that some residues from coprocessing hazardous waste with Bevill raw materials
could remain excluded under the Bevill amendment pending completion of the section 8002
studies. Because the Agency's previous determination of this question (SO FR 49190
(Nov. 29,1985)) could have been more fully explained, the Agency has decided to reopen
the question in this rule and to respond to the public comments.

       The Agency's consistent position on this issue is that so long as the processing of
hazardous waste does not significantly affect the character of the waste residues as high
volume/low hazard, then those wastes can remain excluded under the Bevill amendment
Put another way, the wastes can potentially remain the type of material that Congress told
the Agency to study before imposing subtitle C regulation.

       Instead of focusing on the question of whether coprocessing hazardous waste
affects the composition of the residues from a Bevill device, some commenters would have
it that the mixture  and derived-from rules apply to the residues, so that the residues are
subject to subtitle C (assuming listed wastes are coprocessed) regardless of the actual effect
of burning hazardous waste. At the least, the statute does not compel this result. In the
case of utility boilers burning fossil fuels, the statute states explicitly that wastes "generated
primarily from the combustion of coal or other fossil fuels" is to be excluded. See section
3001(b)(3)(A)(i).  Thus, some type  of co-combustion is expressly authorized. With
respect to die two remaining categories of Bevill waste (wastes from processing ores and
minerals and cement kiln dust), the Bevill amendment (section 3001(b)(3)(A)) does not use
the term "primarily", but does not expressly  address the question of whether the exemption
applies when the residues are produced in part from burning hazardous waste. Thus, read
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literally, dust from a cement kiln that burns hazardous waste along with normal raw
materials could be termed "cement kiln dust".84

       If there were doubt on this point, the Agency is convinced that it is dispelled by the
1984 amendments. Sections 3004(q)(l) and 3010(a) both state explicitly that "(nothing in
this subsection shall be construed to affect or impair the provisions of section 3001 (b)(3)"
(the Bevill amendment). This language would be meaningless unless it allowed some
residues from Bevill devices burning hazardous wastes (specifically hazardous waste fuels)
to remain within the scope of the Bevill amendment Although commenters argued, based
on passages from the legislative history, that the provision should not be given this natural
meaning, the Agency does not find the argument persuasive.  Rather, the legislative history
appears to state that Bevill devices burning hazardous waste fuels will be subject to the
emission standards developed pursuant to section 3004(q).  See H . Rep. No. 198, 98th
Cong.  1st Sess. 41; S. Rep. No. 284,98th Cong. 1st Sess. 37.  Today's rules  accomplish
that result

       At the same time, the Agency is concerned about reading the Bevill amendment in a
manner mat gives it undue scope, such as by allowing Bevill devices to serve as a dumping
ground for other hazardous wastes. We do not view the interpretation adopted today as
allowing the exemption to have undue scope. In the first place, emissions from the Bevill
device itself are regulated.  Second, the facility becomes subject to the facility-wide
corrective action provisions of sections 3008(h) and 3004(u) by virtue of regulation of the
combustion activity.  Thus, potential  problems relating to mismanagement of waste
residues must be evaluated and addressed no later than during the permitting process.

       Most importantly, the Agency believes that the reading adopted strikes a reasonable
balance between the terms of the Bevill amendment and other provisions and regulations
relating to hazardous waste management  A reading that would disqualify residues from
the Bevill amendment if any hazardous waste is burned in the device would exalt form over
substance by barring from Bevill eligibility a residue that was not discemably affected by
84     EPA does not accept the argument that the omission of the word "primarily11 in
regard to ore/mineral processing wastes and cement kiln dust means that die residues must
come exclusively from processing raw materials exclusively. This type of negative
inference is not a compelled reading of die statute, and the legislative history to the
provision in fact indicates that Congress used the term "primarily" with respect to utility
wastes to overrule a 1978 EPA proposed regulation on the scope of utility wastes, rather
man to affect me scope of the remaining two Bevill categories.  126 Cong. Rec. 3363
(1980).
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burning hazardous waste. Given that such material could be exactly the high volume/low
hazard residue that Congress told the Agency to study before regulating, EPA does not
agree with an interpretation that automatically forecloses it from Bevill status.85 In
addition, use of Bevill devices for combusting hazardous wastes provides needed treatment
capacity for a number of hazardous wastes, and the Agency would be reluctant to adopt an
interpretation that discouraged safe processing of hazardous waste by necessarily imposing
hazardous waste disposal costs on residues that might not be affected by the hazardous
waste combustion.

       For all of these reasons, therefore, the Agency is reading the statute in a way that
does not automatically disqualify residues from coprocessing hazardous wastes in Bevill
devices from eligibility for Bevill exempt status.

B. Evolution of Interpretations

       To determine whether the Bevill exclusion continues to apply when the devices
described above86 bum hazardous waste fuel, the Agency stated in 1985 (see 50 FR 49190
(Nov. 29,1985)) that the exclusion continues to apply as long as the hazardous waste is
burned for energy recovery (i.e., not for destruction). The underlying principle for this
determination was that when hazardous waste is used as fuel, the character of the residue
would continue to be determined by the Bevill material (e.g., coal, ores or minerals, or
cement raw materials) being burned or processed. Thus, the residue should remain within
the Bevill exclusion pending special study before it could be regulated under Subtitle C.

       In  the May 6, 1987 proposed rule (52 FR 17012-013), the Agency  suggested
refining these determinations to address residues from industrial furnaces processing ores
or minerals and that also process hazardous waste for materials recovery, and residues
from cement kilns that may process hazardous waste  as an ingredient.  Under that
proposal, such residues would remain within the Bevill exclusion provided that at least 50
percent of the raw material fed to the device consisted of a virgin ore, mineral, or normal
85     EPA notes that in assessing whether residues have been affected by hazardous
waste burning it is using a somewhat more rigorous test for assessing inorganic
contamination  use of the TCLP rather than the synthetic acid rain leaching procedure -
man it used in making the high volume/low hazard determination for mineral processing
wastes. 54 FR at 36630 (Sept 1,1989). The Agency views this as an additional
safeguard to assess the possible effect coprocessing of hazardous waste may have had on
the residues.
86     That is, a boiler buniing primarily coal, an industrial funiace processing primarily
ores or minerals, or a cement kiln processing primarily raw materials.
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raw material. However, residues from devices burning hazardous waste for the purpose of
destruction (ie., for neither energy nor materials recovery) would not qualify for the Bevill
exclusion.

       The Agency has evaluated these interpretations of the applicability of the Bevill
exclusion to waste-derived residues in light of its stated principle that residue that results
from coburning hazardous waste and Bevill raw materials should remain within the Bevill
exclusion provided mat the character of the residue is determined by the Bevill material
(i.e., the residue is not significantly affected by the hazardous waste). As discussed in the
October 1989 supplement to the proposed rule (54 FR 43733-36), the Agency does not
believe that its data base for making these interpretations is sufficient to ensure  that, in
every case, the residue would not be significantly affected by the hazardous waste.
Further, the Agency has reconsidered whether the interpretation that residues generated by
the subject devices when burning waste for destruction are not within the Bevill amendment
is consistent with the stated  principle.   Consequently, the Agency  proposed in the
supplemental notice to require case-by-case determinations of the effect of burning
hazardous waste on residuals. That case-by-case approach is promulgated in today's rule.

C.  Case-By-Case Determinations

       We discuss below which devices are eligible for the Bevill exclusion of residues
and how the two-part test works for determining whether combustion of the waste has
significantly affected the residue.

       1. Eligible Devices.  Until further studies were completed, Congress intended to
exclude from Subtitle C regulation residues from: (1) devices that bum primarily fossil
fuel; (2) industrial furnaces mat process ores or minerals; and (3) cement kilns.  As the
Agency reads these provisions, to be eligible for exclusion from Subtitle C regulation under
the Bevill amendment, the waste-derived residue must be generated from: (1) a boiler
burning primarily coal87; (2) an industrial furnace processing primarily ores or minerals
(otherwise, residues could not be said to come  from processing ores and minerals, but
rather from processing other materials), or (3) a cement kiln processing primarily raw
87     The Agency has determined that residues from cofiring hazardous waste with oil or
gas are not excluded under the Bevill amendment because the character of the residue
would be determined by the hazardous waste. This is because oil and gas generally
produce little residue when burned and, thus, toxic constituents from the hazardous waste
can significantly affect any residue generated. See 50 FR 49190 (Nov. 29,1985). The
Agency is not reopening mis determination in today's rule.
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materials. To implement the provision that, to be eligible for the Bevill exclusion the device
must burn primarily Bevill material, EPA is requiring that a boiler must bum at least 50
percent coal, an industrial furnace must process at least 50 percent ores or minerals, and at
least 50 percent of the feed stock to a cement kiln must consist of normal raw materials.
This requirement also confirms the Agency's long-standing interpretation that the Bevill
exclusion applies only to primary facilities and not to secondary facilities such as secondary
smelters.** See 266.112(a).

       2. Two-Part Test.  Today's rule requires a case-by-case determination as  to
whether the hazardous waste being burned or processed significantly affects the character
of the residue with respect to inorganic and organic toxic (i.e., Appendix Vffl, Part 261)
constituents.  The  residue is considered to be significantly affected  if both: (1)
concentrations of toxic (Appendix VIII) compounds in the waste-derived residue are
significantly higher than in normal (i.e., without burning/processing hazardous waste)
residue; and (2) toxic compounds are present in the  waste-derived residue at levels that
could pose  significant risk to human'health. Part One of the test need not be conducted if
the waste-derived residue passes Part Two of the test (i.e., if the health-based concentration
limits are not exceeded). Such a waste would still meet the high volume/low hazard Bevill
threshold.

       a. Pan One - Comparison with Normal Residues.  Part One of the test requires a
comparison of hazardous waste-derived residues with  normal residues to determine if toxic
compounds are present at statistically significant higher levels.  See 266.112((b)(l). The
toxic compounds of concern are any compound listed on Appendix VIU, Part 261, that
may reasonably be expected to be a constituent in the hazardous waste plus the list (see
Appendix Vffl to the rule) of 31 organic compounds that are common products  of
incomplete combustion (PICs) from burning hazardous waste.  The total concentration of
each compound of concern in the residues is to be determined.89 Analytical procedures are
provided in Test Methods for Evaluating Solid Waste. Physical/Chemical Methods (SW-
846) incorporated by reference in 260.1 l(a).
88     in support of mis reading, one court has held that residues from a secondary lead
smelter are not covered by the Bevill amendment Deo Co. v. EPA (WJD. Ala. 1986).
89     We note lhat Part One of the test considers the total concentration of each
compound, while Part Two of the test considers, for metals, the concentration in an extract
generated from the Toxicity Characteristic Leachate Procedure (TCLP).
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       The rule requires die use of a statistical test to compare the concentrations of toxic
 constituents in samples of normal (without burning/processing hazardous waste) residues
 with samples of waste-derived residues. In the statistical test, the 95th percent confidence
 interval about the mean of the normal residue concentrations (using a "t" distribution) is
 used to determine the upper 95th percent confidence interval about the mean. Procedures
 that must be used to determine the upper 95th percent confidence interval about the mean
 are prescribed in "Statistical Methodology for Bevill Residue Determinations" in Methods
 Manual for Compliance with the BIF Regulation, incorporated by reference in 260.1 l(a).
 A minimum of ten composite samples must be obtained and analyzed to represent the
 normal residue in order to effectively calculate the upper 95th percent confidence interval
 about the mean. This is the concentration that the waste-derived residue may not exceed to
 pass Part One of the test The waste-derived residue must be characterized by composite
 samples with a composite period not to exceed 24 hours to ensure that residues are
 managed properly and promptly  (i.e., as exempt residues or hazardous waste) and to
 provide for effective enforcement  The sampling approach must be based on (and be
 consistent with) representative sampling protocols described in SW-846 and must be
 documented by recordkeeping.

       If operating conditions change so that concentrations of toxic compounds in normal
 residue may (would have) decrease(d), the owner and operator must re-establish the
 "baseline" concentrations in normal residue and use the lower baseline levels for the test.
 This is necessary to ensure that owners/operators do not use the most contaminated raw
 materials in order to bum more hazardous waste, and then switch back to their normal raw
       b.  Part Two.- Comparison with Health-Based Limits.  Part Two of the test
requires a comparison of the concentration of toxic constituents in the waste-derived
residues with health-based limits the Agency has established in Appendix VIU to the rule.
The comparison is made to determine if toxic compounds in the waste-derived residue are
present at levels higher than the health-based limits. The toxic compounds of concern are
me same as for Part One of the test - any compound listed on Appendix Vffl, Pan 261,
that may reasonably be expected to be a constituent in the hazardous waste plus the list (see
Appendix DC to the rule) of 31 organic compounds that are common products of incomplete
combustion (PICs) from burning hazardous waste.   The total concentration of each
nonmetal compound of concern in the waste-derived residue must be compared with the
health-based limit In addition, the concentration of each metal of concern in an extract

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from the Toxicity Characteristic Leaching Procedure (TCLP) must not exceed the health-
based limits.

       The Agency does not have adequate health effects data (e.g., MCLs, RfDs, unit
risk values) to establish health-based limits for many compounds listed in Appendix Vm,
Part 261. Consequently, we have conservatively established a health-based limit for such
compounds based  on the 5th lowest percentile value of the health-based values for
nonmetal compounds established in Appendix Vn to the rule. That value is 0.002 mg/kg.
This is the same approach EPA used to establish a RAC for compounds where insufficient
health effects data were available to establish a RAC or RsD for the compound.

      , The rule requires the use of total concentrations of nonmetal compounds rather than
extract concentrations for the test of health significance because the purpose of burning
toxic nonmetal compounds in these devices should be to destroy the compounds. (Use of
total nonmetal concentrations thus serves as a partial check that combustion is being
conducted properly.)  The health-based limits for the metals in Appendix Vm of the rule
are the Toxicity Characteristic (TC) limits (see 261.24)  for those metals for which TC
limits have been established. To establish health-based limits for the other metals, the
Agency applied  the same  100 fold dilution factor to leachate concentrations used to
establish the TC limits. The Agency has also used this same dilution factor in  assessing
whether mineral processing wastes satisfy the low hazard prong of the Bevill test See 54
FR 36630 (Sept 1,1989).

       To determine if the concentrations of toxic compounds in the waste-derived
residues are higher than the health-based limits, owners and operators must obtain  and
analyze composite samples of waste-derived residues with a composite period not to exceed
24 hours. The sampling approach must be based on (and be consistent with) representative
sampling protocols described in SW-846 and must be documented by recoidkeeping.

D. Recordkeeping

       Owners and operators must maintain for a period of three years or until the facility
is issued a permit, whichever is longer, records of sampling and analyses of residues to
support claims mat the waste-derived residue retains the Bevill exclusion.
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. Other Considerations

       1. Generic Determinations. In the October 26,1989 supplement to the proposed
rule, the Agency requested data and information that it could use to support: (1) generic
determinations of levels of toxic constituents in  normal (i.e., generated without
burning/processing hazardous waste) residues; and (2)  generic determinations that certain
waste-derived residues are not significantly affected  by burning/processing hazardous
waste,  and, thus, remain excluded without the need  to make the case-by-case
demonstration.

       a. Normal Residues. After review of comments on the 1989 supplemental notice,
the Agency concluded that it is not practicable to establish generic concentrations of toxic
constituents in normal residues.  Commenters noted that there were so many site-specific
variables that affect the concentration of toxic constituents in normal residues that this
approach was not workable. Variables include the type of industrial furnace, type of fuels
burned, and type  and source of raw materials used by industrial furnaces. The Agency
initially considered establishing generic concentration  levels in normal residues to avoid
giving an advantage to facilities that use fuels or raw materials with high  (i.e., higher than
normal for the industry) levels of toxic constituents.  Normal residues from such facilities
would have high  levels of toxic constituents. Thus, waste-derived residues from such
facilities could also have high levels of toxic constituents. Consequently, such facilities
could bum/process hazardous waste with high levels of toxic constituents without losing
the Bevill exclusion of residues. We note that enforcement officials will give priority
consideration to those facilities whose residues fail Part 2 (health-based limits) of the test to
determine Bevill  applicability and rely on Pan 1 (comparison with normal residues) to
retain the exclusion.  Owners and operators must be able to support, at any time, that the
nonhazardous waste feedstreams being fed into the device when  hazardous waste is fired
are the same (or would not decrease the concentrations of toxic constituents in residues) as
those fired when the concentrations of toxic constituents  in normal residues were
determined.  If the concentrations of toxic constituents in nonhazardous feedstreams
decrease significantly from those concentrations when the normal residue was generated for
purposes of establishing normal concentrations of toxic constituents  (or if design or
operating conditions change such mat levels of toxic constituents in normal residue could
decrease significantly), men the owner/operator must establish new, lower, concentrations
for normal residue.
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       b.  Excluded Residues.  The Agency also concluded that it is not practicable to
make generic determinations that certain waste-derived residues are not significantly
affected by burning or processing of hazardous waste and, so, remain excluded.  This
approach is not workable given that the exclusion would have to be conditioned on a
number of factors including:  (1) the composition, feed rate, and method of feeding the
hazardous waste; (2) the type of device; (3) the composition, feed rate, and method of
feeding any other fuels; and (3) the composition, feed rate, and method of feeding any raw
materials. The data base to support such determinations is not available.  Moreover, any
such generic exclusion that is necessarily conditioned on so many factors would be of little
practical use to die regulated community given the variability of normal operations.

       2. Burning for Destruction. The case-by-case approach to determine the effect of
coburning  on residues from Bevill devices focuses on the residues that are actually
generated rather than on the purpose for which the hazardous waste is burned.  Thus,
residues generated from burning hazardous waste in boilers and industrial furnaces for the
purpose of destruction90 are eligible to retain the Bevill exclusion.  The Agency's historic
approach to the issue of cogenerated residues has been to focus on the character of the
residues to ascertain what determines their character - the Bevill material or the hazardous
waste being burned/processed (see 50 FR 49190 (November 29,1987)). The statute itself
does not directly specify that the purpose of the burning is a relevant criterion, but instead
states that certain types  of waste are  excluded from Subtitle C regulation pending
completion of required special studies. Since the Bevill devices would still be engaged in
the Bevill activity, and composition of the residues would potentially be unaffected, the
Agency sees no absolute bar to allowing Bevill status for such residues.
90     For example, wastes with low heating value mat are not burned for materials
recovery or as an ingredient are burned for destruction. We note that such wastes may be
burned only by new facilities as incinerators under an operating permit or by those existing
facilities operating under interim status that also have certified compliance with the
applicable emissions standards.
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 PART FOUR:  MISCELLANEOUS PROVISIONS

 I.  Regulation of Carbon Regeneration Units
 A. Basis for Regulating Carbon Regenerating Units as Thermal Treatment Units

       In today's rale, EPA is clarifying the regulatory status of carbon regeneration91
 units.  Since 1980, controlled flame (direct flame) carbon regeneration units which destroy
 organic contaminants adsorbed onto activated carbon have met the definition of incinerator
 and were subject to regulation as such, while carbon regeneration nonflame thermal units
 were treated as exempt reclamation units. Today's rule defines carbon regeneration unit
 and incinerator (see 260.10) to ensure that both direct flame and nonflame thermal carbon
 regeneration units are regulated as thermal treatment units under the interim status standards
 of Pan 265, Subpart P, and the permit standards of Part 264, Subpart X.

       One commenter expressed concern that the thermal treatment standards of Subpart
 X were vague.  EPA disagrees and points out that  Subpart X,  Part  264 covers
 miscellaneous hazardous waste management units that do not or may not fit the description
 of any of the units covered by other Part 264 regulations.  Without Subpart X, these
 unregulated units could only operate as interim status facilities and could  not be fully
 permitted, thereby preventing the construction of new units or some expansions of existing
 units. EPA recognized that some types of new units that were not previously allowed to be
 constructed could reduce risks to human health and the environment from the management
 of hazardous waste.  Promulgation of Subpart X generic permitting standards was intended
 to allow such construction and flexibility for technical development and innovation and to
 cover diverse technologies and units.  The Subpart X standards specify that health and
 environmental safety must be a primary concern during the management of hazardous
 wastes in  miscellaneous  units. If the need arises, the Agency may develop specific
 technology standards in the future (see 52 FR 46964, December 10, 1987). Although
 several commenters supported the application of Pan 264, Subpart O incinerator standards
 to direct flame and nonflame devices, EPA has decided against this since demonstration of
 conformance  with the DRE standards (and the proposed CO/THC standards) may not be
 achievable or warranted for carbon regeneration units considering the relatively low levels
of toxic organic compounds adsorbed onto the activated carbon.
      The term "regeneration" includes reactivation of used carbon for reuse.

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B. Definition of Carbon Regeneration Unit and Revised Definition of Incinerator

       Several commenters requested that EPA consider revising the definition of a carbon
regeneration unit so that certain units used for air emissions control, wet oxidation, and
general recycling, would not be regulated.  Activated carbon units used as air emission
control devices of gaseous industrial process emissions will not necessarily be regulated
because trapped organics in such columns are not hazardous wastes because  the gas
originally being treated is not a solid waste (it is an uncontained gas92), and therefore any
condensed organics do not derive from treatment of a  hazardous waste.  (The nongas
residues from these devices could be hazardous wastes if they are listed or if they exhibit a
characteristic, however.) However, regeneration or reactivation of carbon used to control
air emissions from hazardous waste treatment, storage, or disposal facilities (e.g., under 40
CFR 265 and 265, Subpart II, June 21,1990, 55 FR 25454) is subject to regulation as a
RCRA thermal treatment unit

       We considered whether other 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 adsorb waste contaminants, which  are now
destroyed in the "regeneration" process (just as rinsing out a container of hazardous waste
is a stage in the storage process and does not constitute recycling of the container).
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, and therefore are clarifying today that they are regulated as thermal
treatment units.

       We note mat this revision also applies to those carbon regeneration units that, while
in active service treating wastewater, meet the definition of wastewater treatment units in
260.10.  Such units are  exempt from RCRA permitting  standards while  treating
wastewater. However, these units are not exempt from  RCRA regulation when  they are
being regenerated because they are not treating wastewater during the regeneration  process.
Rather, me activated carbon columns themselves are being treated thermally.  The thermal
regeneration unit is subject to Part 265, Subpart P (existing units) or Part 264, Subpart X
(new units).
92    See 47 FR at 27530 (June 30,1982) and 54 FR at 50973 (Dec. 11,1989).
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C.  Units in Existence on the Effective Date of the Rule are Eligible for Interim Status

       Although certain carbon regeneration units may technically have met either the 1980
or 1985 definitions of incinerator, the Agency believes that there has been legitimate doubt
as to these units' regulatory status (which is why the Agency undertook this rulemaking to
clarify the status). The units might potentially have been classified as incinerators, thermal
treatment units, or perhaps exempt recycling units.  It would also have been confusing to
interpret the rules in a manner that carbon regeneration units were not all regulated in the
same way, given that there functions and activities are roughly identical whether or not the
units are direct-fired. In fact, the most natural classification of these units, and the one the
Agency intended, is as thermal treatment units. (EPA does not believe that these are
recycling units, but rather that regeneration is a continuation of the waste treatment process,
that process consisting of removal of pollutants by  adsorption followed by their
destruction. Nor does the Agency believe that incinerator standards make technical sense
for these devices, as noted above.) In addition, few if any of these units have actually been
regulated as incinerators in practice.

       For these reasons, EPA is  finding  pursuant  to 270.10(e)(2)  that there  was
substantial confusion as to which owners or operators of carbon regeneration units were
required to submit a Part A application and that this confusion is attributable to ambiguities
in the subtitle C rules.  Accordingly, such owners and operators may submit Part A
applications by the effective date of today's regulations and be eligible for interim status
under Part 265, Subpart P (assuming they meet remaining requirements for interim status
eligibility, and the facility is not already subject to interim status for other units).

IL   Sludge Dryers

       In today's rule, the Agency is clarifying the regulatory status of sludge dryers. In
particular, the rule adds a definition of "sludge dryer" to 260.10 and amends the definition
of "incinerator" in 260.10 to specifically exclude sludge dryers.

       On November 17,1980 (45  FR 76074), EPA suspended the applicability of the
RCRA permitting requirements (40 CFR Pan 122, which is now codified as part 270) and
hazardous waste management facility standards (40 CFR Parts 264 and 265) to owners and
operators of devices meeting the definition of "wastewater treatment unit" in 40 CFR
260.10 and 270.2.
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      Since promulgation of this wastewater treatment unit exclusion from RCRA
permitting requirements, the Agency has received numerous requests to determine if certain
types of units satisfy the definition of "wastewater treatment unit" and, therefore, would
not require a RCRA permit Many of these requests have concerned the regulatory status
of thermal treatment units, particularly sludge dryers.  Commenters have also requested
clarification of the regulatory status of sludges from thermal treatment units.  Most of the
requests have been from owners and manufacturers of sludge dryers.  The Agency believes
mat approximately 40 sludge dryers are currently being used in the metal finishing industry
to dehydrate metal hydroxide sludges (EPA Hazardous Waste F006) generated in the
treatment of wastewater.

      In response to these inquiries, EPA distributed policy memoranda to the Regional
offices explaining that a sludge dryer is included within the scope of  the wastewater
treatment tank exclusion, provided that it meets the definition of "wastewater treatment
unit."  (See OSWER Policy Directives 9503.52-1A and 9503.51-1A,  available upon
request from the RCRA Hotline.) In addition, with respect to the status of the sludges
themselves, they are hazardous waste if identified or listed (including by application of the
mixture and derived-from rules) and are subject to regulation when removed from the
tanks.

      Despite  the original November  17, 1980 preamble discussion  and the policy
clarification, the regulatory status of sludge dryers has continued to be unclear. One reason
for the confusion is because it is not clear whether a sludge dryer satisfies the third
component of the definition of wastewater treatment unit (i.e., whether it  meets the
definition of a "tank" or "tank system").  The Agency has determined that sludge dryers
that are integrally equipped with feed or discharge hoppers that provide for an accumulation
of waste satisfy the definition of "tank system."93 Based on information available to EPA
at this time, it appears the most sludge dryers are so equipped.  (Those sludge dryers that
are not so designed may still be considered tanks, but a case-by-case decision must be
made.)  The Agency has also determined that other types of equipment not obviously
meeting  the "tank" definition, such as presses, filters, sumps, and  other types of
93    We nc that sludge diyere that are a pan of a wastewastertreamiem facility that is
subject to regulation under either section 402 or 307(b) of the Clean Water Act) and that dfl
OOt meet the definition of a tank system are subject to RCRA regulation as thermal treatment
units, just like sludge dryers that are not a pan of a wastewater treatment system.
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 processing equipment, are covered within the meaning of the term "tank" or "tank system"
 when used in Ac context of mis exclusion (see OSWER Policy Directive 9503.52-1 A).

       Another reason that the regulatory status of sludge dryers has been the subject of
 many questions may be because some sludge dryers technically meet the current definition
 of an "incinerator," although EPA never intended to regulate direct-flame (or nonflame)
 sludge dryers as incinerators. When EPA amended the definition of "incinerator" to use
 physical design criteria rather than a primary purpose test (i.e., purpose of burning) to
 define an incinerator, it did not intend to bring sludge dryers under regulatory control as
 incinerators. (See 50 FR 625, January 4,1985, indicating that the revised definition would
 not bring large numbers of devices other than incinerators under incinerator standards.)
 Under the former primary purpose definition, sludge dryers were not incinerators.
 Although under the 1985 revised definition of incinerator sludge dryers could be classified
 as incinerators, this was not EPA's intention. The Agency is clarifying this ambiguity by
 clearly regulating all nonexempt sludge dryers (i.e., those not meeting the definition of
 "wastewater treatment unit"  under  today's rule, as discussed below) under the interim
 status standards of Part 265, Subpart P ("Thermal Treatment"), and the permit standards of
 Pan 264, Subpart X ("Miscellaneous Units"). See 55 FR 17866 (April 27, 1990) for
 details.  Given that such units  managing hazardous waste always were subject to some type
 of regulation, they are not  newly eligible for interim status as  a result of today's
 clarification.

       Even though as a result of this amendment sludge dryers are potentially subject to
regulation under Subpart P  of Part 265 and Subpart X of Pan 264 as other thermal
treatment units, sludge dryers that meet the  260.10 definitions of "wastewater treatment
unit" and "tank" or "tank system" continue to be exempt wastewater treatment units under
 264.1(g)(6) and 265.1(c)(10). The Agency believes that virtually all sludge dryers meet
the tank/tank system definition and, therefore, would be exempt when used as pan of a
wastewater treatment system.

A. Jufy 1990 Proposal

       To better clarify the regulatory status of sludge dryers, the Agency proposed on
July 18,1990 (55 FR 29280) a definition for "sludge dryer" to clearly distinguish them
from other thermal treatment units:  Sludge dryer means any enclosed thermal treatment
device that is used to dehydrate sludge and that has a maximum total thermal input of 1,500
Btu/lb of sludge treated on a wet-weight basis.
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      In the same notice, the Agency also proposed to amend the definition of a
wastewater treatment unit to say that sludge dryers were the only thermal treatment devices
(heretofore) meeting the definition of a wastewater treatment unit that were exempt from
regulation.

      Today's role clarifies that sludge dryers meeting the definition of a wastewater
treatment unit are exempt from regulation (by promulgating a definition of sludge dryer and
revising the definition of incinerator to exclude sludge dryers).  EPA also proposed a
further clarification that other devices that use heat to treat wastewaters were not to be
considered eligible for the wastewater treatment tank exemption. The Agency indicated,
without discussion, that it had not intended for such units to be eligible for the exemption
and that the proposal was a simple clarification which reflected common understanding
within the Agency and the regulated community.

       Commenters disagreed with this assessment of the regulations, and the Agency has
since studied the issue in more depth. It appears that the Agency was mistaken in its
assessment both of die current intended scope of the rule and of common understanding of
what the rule covers.  With respect to such devices as evaporators and steam strippers used
in wastewater treatment, die Agency has in fact traditionally regarded such units as eligible
for the wastewater  treatment exemption.   See 55 FR at 25467 (June 21,  1990).
Commenters likewise indicated their understanding that current rules exempt such devices.

       Given the narrow scope of the proposal, the clear indication that any change would
not be a clarification of existing rules  (as indicated) but rather a potentially far-reaching
alteration, and the absence of any discussion (or study) of whether a substantive change in
regulatory status of these devices is warranted, EPA cannot go forward. Consequently, we
are not adopting any other pan of the definition of wastewater treatment unit discussed in
the 1990 notice.

B.  Summary of Public Comments

       EPA received comments regarding the status of sludge dryers in response to the
April 27,1990 BIF notice and the July 18,1990 notice discussed above.

       Many of the commenters to these notices supported the inclusion of sludge dryers
in the wastewater treatment unit (WWTU) definition.  The commenters, however,
requested clarification on whether units similar to sludge dryers (e.g., evaporators) would
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 also be eligible for the WWTU exclusion. As discussed above, other devices using heat
 that meet the definition of wastewater treatment unit would continue to be exempt from
 RCRA regulation (except, of course, an incinerator, boiler, or industrial furnace burning
 hazardous waste).

       Eleven commenters to these proposals stated that the maximum 1,500 Btu/lb
 thermal input requirement in the sludge dryer definition is too low.  Citing low thermal
 efficiencies (especially for indirect-fired dryers), these commenters recommended thermal
 input requirements ranging from 1,700 to 3,300 Btu/lb.

       After consideration of the commenters' concerns and further review of the technical
 background information on the thermal input limit, the Agency is today revising the thermal
 input limit to 2,500 Btu/lb wet sludge. The Agency believes that depending on the nature
 of the treatment system, the thermal input to a bona fide sludge dryer (i.e., a device that is
 not an incinerator) can be as high as 2,500 Btu/lb.

       Several commenters also requested that EPA clarify that the total thermal input limit
 was not to include the heating value of the sludge itself given that a number of sludges that
 are dried have as-fired heating values of 1,000 to 2,700 Btu/lb. The Agency agrees. The
 final rule explicitly excludes the heating value of the sludge from the 2,500 Btu/lb limit on
 thermal input With this clarification, however, we note that the primary purpose test ~
 dehydration - is the primary distinction between a sludge dryer and an incinerator. This is
 because a sludge incinerator can readily meet the thermal heat input limit of 2,500 Btu/lb
 when the heating value of the sludge itself is not included.  However, the primary purpose
of a sludge dryer is dehydration while the primary purpose of an incinerator is volume
reduction to produce an ash residue. Thus, we believe that the definition in today's rule
adequately distinguishes between sludge dryers and incinerators. Nevertheless, it should
be noted that any person claiming the wastewater treatment unit exemption for a sludge
dryer must have documentation to support that the primary purpose of the device is to
dehydrate sludge, not to destroy sludge to produce an ash residue.

       The Agency received many responses to its request for comments on whether it is
necessary to specify a minimum percent volume reduction in the definition of a sludge
dryer. Although one commenter stated that a percent volume reduction should be specified
in the sludge dryer definition, twelve of the commenters stated that such a requirement
would be arbitrary, confusing, unworkable, and costly to enforce. Two of the commenters
stated that a minimum percent weight reduction would be more appropriate. In today's
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rule, the Agency has decided not to specify a minimum percent volume (or weight)
reduction in the definition of a sludge dryer. The Agency believes that such a specification
would be difficult to support and would not be needed to distinguish sludge dryers from
incinerators.

       Several commenters stated that the Agency should address emissions of volatile
organics from units such as  sludge dryers. In addition, two commenters recommend a
1,000 Btu/lb thermal input limit for the device to control volatile emissions from sludge
dryers.  EPA recognizes the  need to address volatile emissions from sludge dryers and
intends to evaluate alternatives for regulating these units at a later date. However, because
this rule simply clarifies that  EPA intended for sludge dryers that meet the definition of a
wastewater treatment unit to be exempt from the RCRA rules, it would be inappropriate to
address volatile organic emissions at this time.  Nonetheless, sludge dryers that do not meet
the definition of a wastewater treatment unit (e.g., sludge dryers that are not a pan of a
wastewater treatment facility that is subject to regulation under either section 402 or 307(b)
of die dean Water Act) are subject to regulation as thermal treatment units under Subpart X
of Part 264. Under those standards, the Agency may apply controls on volatile organic
(and other) emissions as necessary to protect human health and the environment

       After considering comments  on the proposed sludge dryer definition, EPA is today
promulgating the following definitions:

       Sludge dryer means any enclosed thermal treatment device that is used to dehydrate
sludge and that has a maximum total thermal input, excluding the heating value of the
sludge itself, of 2,500 Btu/lb of sludge treated on a wet-weight basis.

       Incinerator means any enclosed device that: (1) uses controlled flame combustion
and neither meets the criteria for classification as a boiler, carbon regeneration unit, or a
sludge dryer, nor is listed as  an industrial furnace; or (2) meets the definition of infrared
incinerator or plasma arc incinerator.
      Classification of Coke and By-Product Coal Tar

A. AISI Petition

       The American Iron and Steel Institute (AISI) petitioned EPA with respect to the
practice of recycling tar decanter sludge by die following means:
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        1. Applying the sludge to coal prior to or just after charging the coal into the coke
           oven; and,

        2. Combining the sludge with coal tar prior to its being sold.

       The coke and the coal tar are often used as fuel and so have been classified as solid
 wastes and hazardous  wastes since they are fuels produced or otherwise containing a
 hazardous waste   EPA Hazardous Waste No. K087, tar decanter sludge.   See
 261.2(c)(2)(i)(B).  These hazardous waste fuels have been exempt from regulation under
  261.6(a)(3)(vii) and 50 FR 49170-171  (November 29,1985). The AISI has requested
 that EPA not classify such coke or coal tar as solid wastes.  AISI submits that recycling the
 decanter sludge in this manner does not significantly affect the concentration of toxic metal
 and organic constituents of the coke or coal tar. EPA has indicated that waste-derived fuels
 could be classified as products under such circumstances, "since the more waste-derived
 fuels from a process are like products from the same process produced by virgin materials,
 the less likely EPA is to classify the waste-derived fuel as a waste." SO FR 49169 (Nov.
 29, 1985). To support its request, the AISI submitted data on the metals and organic
 constituents in coke, coal tar, and tar decanter sludge both with and without sludge
 recycling. The data and the Agency's response are discussed below.

 B. Process Description

       Coke used for making iron is manufactured through the destructive distillation of
 coal in ovens. A typical oven holds approximately  13 tons of coal which is heated to a
 temperature of about 2000F. Generally 20 to 100 ovens are located adjacent to each other
 in a "coke oven battery." The destructive distillation or "coking" process takes about 15-18
 hours. During mat time period, about 20-35 percent of the coal is converted to coke oven
 gas (COG) consisting  of water vapor, tar, light oils, heavy hydrocarbons, and other
 chemical compounds. The COG is collected from the top of the coke oven and, in most
 cases, sent to the by-product plant via the coke battery main. The COG is then cleaned by
 removing wastes and by-products prior to being burned, generally in the coke oven under-
 firing system. As a first step in die COG cleaning process, the coal tars, consisting of
 heavy hydrocarbons, are condensed from the gas. In addition, most of the paniculate that
escapes from the ovens is collected in the  tar. This paniculate is believed to consist
principally of coal fines. The paniculate or solids are then removed from the tar in the tar
decanter.  The coal  tar is then burned as fuel or sold for use in various products such as
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roofing cement  The sludge has been listed as EPA Hazardous Waste No. K087 and is
disposed of or recycled either by mixing with coal prior to being charged to the coke oven
or mixing with coal tar after physical processing (grinding) prior to sale.

       Approximately 8-12 gallons of tar are produced per ton of coke.  In addition,
approximately one pound of tar decanter sludge is produced for every 40 pounds of tar
produced.

C. Basis for Approval of the AISI Petition

       The AISI submitted data from metal and organic chemical analyses for the coke,
coal tar, and tar decanter sludge from four plants. The Agency reviewed these results and
determined the following:
       1.  The recycling of tar decanter sludge by application to the coal charge does not
          appear to have a significant effect on the chemical composition of coke;
       2.  The organic chemical composition of the tar decanter sludge does not appear to
          be significantly different from the coal tar, and,
       3.  The concentration of one metal, lead, in the sludge appears to be slightly higher
          than in the coal tar. However, the increase does not appear to be statistically
          significant due to the high variability of the concentration values.

       Based on the above and the fact that there is such a small quantity of sludge relative
to the quantity of coke and coal tar produced by the coking process, EPA believes that
sludge recycling, as described here, does not significantly affect the concentration of toxic
metals and organic constituents in coal tar or coke. Furthermore, coke, coal tar, and the
decanter tank tar sludge are similar materials formed in a single process and contain the
same contaminants. In this circumstance, when the coke and the decanter tank tar sludge
are very nearly the identical substance and, moreover, come from a single process, the
Agency is warranted in exercising its discretion to determine that this management of the
sludge is "not part of the waste disposal problem", and hence that the coke product is no
longer a RCRA solid waste. American Mining Congress v. EPA. 907 F. 2d 1179,1186
(D.C Cir. 1990).  Therefore, in today's rule, EPA is classifying such coke and coal tar as
products, not wastes.  As a result, the coke and coal tar will be excluded under 40 CFR
261.4 from the definition of solid waste and  not subject  to RCRA hazardous waste
management regulations when used as a fuel. A necessary corollary to this action is also to
exclude the coking process from regulation when K087 is used as an ingredient to produce
coke. Given mat K087 is for practical purposes just like other materials used to produce
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coke and comes from the same process as these other materials, it would be anomalous to
assert RCRA control over the coking process. Again, this form of sludge management ~
which is the same as raw material management  does not appear to EPA to be part of the
waste disposal problem.94  (In addition, coke ovens are subject to a special regulatory
regime under amended section 112(i)(8) of the dean Air Act, and RCRA regulation of this
particular practice could disrupt the Qean Air Act regulatory scheme. Thus, the Agency
views RCRA regulation of this practice as inappropriate in any case.)

       This exemption applies only to the waste-derived fuels and only when derived from
tar decanter sludge, K087. Thus the tar decanter sludge, K087, is subject to full RCRA
regulation prior to recycling. In addition, the exemption  does not extend to coke or coal tar
produced from hazardous waste (e.g., spent solvents) other than tar decanter sludge, EPA
Hazardous Waste K087.

IV.  Regulation of Landfill Gas

       In the November 29,1985 final rules regulating hazardous waste burned for energy
recovery, the Agency indicated that gas recovered from hazardous waste landfills that is
burned for energy recovery in boilers or industrial furnaces is not regulated under the
waste-as-fuel rules. 50 FR 49171. EPA took this action in order to study further the extent
to which there might be jurisdictional limits on the Agency's authority  under section
3004(n) of RCRA to regulate gaseous emissions from hazardous waste. Id.  In today's
rule, we are amending mis language slightly by indicating that the exemption also applies to
gas recovered from solid waste landfills.  Therefore, gas recovered from a solid waste
landfill that exhibits a hazardous characteristic would also be exempt from today's rule
when burned for energy recovery in a boiler and industrial furnace.

      In addition, the Agency solicited comment, in the May 6,1987 proposed rule, on
whether the hydrocarbon phase of the condensate removed from recovered gas should also
be exempt from regulation when burned as fuel (52 FR 17021).  Two commenters
responded that the condensate contains chemical constituents similar to fossil fuels such as
kerosene or gasoline and that the handling and burning of the gas condensate poses no
significant hazard to human health. The commenters encouraged the Agency not to regulate
94     The Agency is not aware of any other hazardous wastes that are burned in coke
ovens as an ingredient that arc just like other materials used to produce coke. If such
materials are used, the Agency would encourage the industry to provide the necessary
information in order to determine whether the exclusion should be modified.
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the hydrocarbon phase of the landfill gas condensate unless the hydrocarbons exhibit a
Subtitle C characteristic of a hazardous waste. However, data on condensate composition
provided by one respondent was vague and represented only one source of condensate.
Absent adequate data, EPA is not promulgating an exemption from regulation of the
hydrocarbon phase of the landfill gas condensate at this time. Facilities that wish to burn a
landfill gas condensate may consider whether they are eligible for the small quantity burner
exemption promulgated in this rule.

V.  Definitions of Infrared and Plasma Arc Incinerators

      Today's rule establishes definitions for infrared and plasma arc incinerators and
revises the definition of incinerator to explicitly include these devices. As discussed in the
April 27,1990 proposed amendments to the incinerator standards (55 FR at 17869-70),
EPA is clarifying that  these devices are incinerators rather than (other) thermal treatment
units subject to regulation under Subpart X of Part 264 (or Subpart P of  Pan 265 for
interim status units) because: (1) although these devices use nonflame sources of thermal
energy to treat waste in the primary chamber, they  invariably employ controlled flame
afterburners to combust hydrocarbons driven off by  the primary process (and, thus, they
meet the definition of an "incinerator" under 260.10); and (2) the incinerator standards are
workable and protective for these units.

      We note that today's action merely clarifies the regulatory status of these devices.  It
does not subject them to regulation for the first time; they have been regulated since 1980.
Thus, interim status is not reopened for these devices.
PART FIVE:  ADMINISTRATIVE, ECONOMIC, AND ENVIRONMENTAL
IMPACTS,  AND  LIST  OF SUBJECTS
L State Authority
A. Applicability of Rides 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 Pan 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 19S4 (HSWA), a State
with final authorization administered its hazardous waste program entirely in lieu of EPA
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 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
 authorized State until die 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.

       The majority of today's rule is promulgated pursuant to Section 3004(q) of RCRA,
 a provision  added by HSWA.  (The provisions that are not promulgated pursuant to
 HSWA are the provisions for sludge dryers,  carbon regeneration  units,  infrared
 incinerators, and plasma arc  incinerators.) Therefore, the Agency is adding the
 requirements (except the non-HSWA provisions) to Table 1 in 271.1(j) which identifies
 the Federal program requirements that are promulgated pursuant to HSWA and that take
 effect in all States, regardless of their authorization status.  States may apply for either
 interim or final authorization for the HSWA provisions identified in Table 1, as discussed
 in the following section of this preamble.

B. Effect on State Authorizations

       As noted above, EPA will implement the majority of the provisions of today's rule
in authorized  States  until they modify their programs to adopt these rules and the
modification is approved by EPA.  Because these provisions of the rule aze promulgated
pursuant to HSWA, a State submitting a program modification may apply to receive either
interim or final authorization under Section 3006(g)(2) or 3006(b), respectively, for these
provisions on the basis of requirements that are substantially equivalent or equivalent to
EPA's. The procedures and schedule for State program modifications for either interim or
final authorization are described in 40 CFR 271.21.  It should be noted that all HSWA
interim authorizations will expire January 1,1993.  (See 271.24(c).)
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       The provisions of today's rule that are not promulgated pursuant to HSWA -
provisions for sludge dryers, carbon regeneration units, infrared incinerators, and plasma
are incinerators - are not effective in authorized States. Thus, these requirements will be
applicable only in those States that do not have final authorization. In authorized States, the
requirements will not be applicable until the State revises its program to adopt equivalent
requirements under State law.

       40 CFR 271.21(e)(2) requires that States that have final authorization must modify
then- 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 the HSWA portion of today's rule is July 1,1993 if a statutory change is
not needed, or July  1,1994 if a statutory change is needed.  The deadline by which the
State must modify its program to adopt the non-HSWA portion of today's rule is July 1,
1992 if a statutory change in not needed, or July 1,1993 if a statutory change is needed.
These deadlines can be extended in certain cases (40 CFR 271.21(e)(3)).  Once EPA
approves the modification, the State requirements become Subtitle C 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 promulgated today to determine whether they meet die tests for
authorization. Thus, a State is not authorized to implement these requirements in lieu of
EPA until the State program modification is approved. Of course, States with existing
standards may continue to administer and enforce their standards as a matter of State law.

       In implementing the Federal program for the HSWA portion of today's rule, EPA
will work with States under cooperative agreements to minimize duplication of efforts. In
many cases, EPA will be able to defer to the States in their efforts to implement their
programs, rather than take separate actions under Federal authority.

       States that submit their official applications for final authorization less than 12
months after die effective  date of these standards are not required to include standards
equivalent to these  standards in their application.  However, the State must modify its
program by die deadlines set forth in 27121 (e). States that submit official applications
for final authorization 12 months after the effective date of these standards must include
standards equivalent to these standards in their application. 40 CFR 271.3 sets forth the
requirements a State must meet when submitting its final authorization application.
                                      200

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 n.  Regulatory Impacts

 A. Cost Analysis

       1. Background. Prior to publication of the proposed regulations in May 1987, the
 Agency examined the projected compliance costs, economic impacts, and risk reductions
 associated with the proposed rules. This effort consisted of a detailed examination of the
 pre-proposal draft as it was drafted in mid-1986 and a supplement prepared in late 198695
 that examined several changes in tax policy and regulatory approach that occurred after the
 first analysis was completed.96

       The analyses estimated that of the approximately 1,000 BIFs identified as firing
 hazardous wastes, approximately 20 percent were likely to discontinue burning hazardous
 wastes because of the rules, 60 percent would burn small amounts of waste and would
 qualify for the small quantity burner exemption (SQBE), and the remaining 15 percent
 would obtain full permits. Because the final 15 percent of devices represent large facilities,
 however, the impact on the total quantity of waste burned would be small. For example,
 under the "base case" scenario, although 20 percent of the devices would discontinue
 burning hazardous wastes and a number of other devices would reduce the quantity of
 hazardous waste they combust in order to qualify for the SQBE, only 3 percent of the
 quantity of waste combusted in the absence of regulations would be  diverted to other
 devices. The mid-1986 analysis estimated that under this scenario, the aggregate after-tax
 cost of compliance to individual firms would be $5.2 million per year and that the before-
 tax social cost would be $8.2 million per year. Under other sets of assumptions (i.e., other
 scenarios), these costs were likely to be higher, but in all cases were estimated to be less
 than $100 million per year.

       Based on these analyses, the Agency concluded that the total social costs, impact on
 market competition, and the impact on small businesses were such that the proposed
regulations did not constitute a major rule, and that a formal Regulatory Impact Analysis as
described in Executive Order 12291 was not required.
95     U.S. EPA, "Regulatory Analysis for Waste-As-Fuel Technical Standards", Draft
Report, October 1986.
96     U.S. EPA, "Effects of Recent Changes on the Estimated Costs and Benefits of the
Proposed Waste As Fuel Technical Standards", January 1987.
                                      201

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       A number of comments on the economic analysis were received from affected
businesses and other groups. Most of these commenters contended that the cost of
compliance had been underestimated by the Agency. Based on these comments, as well as
changes made in the final regulation compared to the proposed requirements, the Agency
has reexamined and updated the earlier analyses.

       2. Revised Cost Analysis.  As indicated earlier, there have been a number of
changes made in the regulations that are expected to increase the cost of compliance. In
addition, the Federal tax code was changed in late 1986, the cost of goods and services to
the economy as a whole has increased due to inflation, and the estimated cost of specific
requirements associated with the BIF regulations have been reexamined. The new analysis
focused on assessing the impact of changes in compliance costs on typical facilities, and
did not reexamine the impact of these changes on the selection of regulatory options by
individual facilities.  In addition, no effort was made to explicitly examine the impact of the
final rules on the economic competitiveness of individual firms or industries, nor  on the
reduction in public health risks.

       The primary changes that have occurred in the regulations subsequent to proposal
have been revised requirements for continuous emission monitoring of CO and HC;
addition of the PM standard, interim status compliance procedures, and limits on emissions
of several additional metals and Cl2 ^ increases in recordkeeping, sampling, and
analysis requirements. The impact of these changes plus the impact of tax code changes
and inflation on the before- and after-tax costs of the BIF regulations are summarized in
Table 1. When combined with the original "base case" cost estimates prepared in 1986, the
revised cost estimate for the promulgated rule is $15.2 million per year before taxes and
$10.3 million per year after-taxes.

       The increased cost for CO and HC monitoring reflects the costs for installation of a
more comprehensive CO monitoring system than was originally estimated and the cost of
installing HC monitors on an estimated 20 devices (primarily cement kilns) that will operate
under the Tier 0 CO and HC limits. The zero cost increase associated with the PM
emission standard reflects the expectation that BIFs complying with the metals standards
will achieve the 0.08 gr/dscf standard, and that most existing industrial furnaces and some
boilers are already subject to this emission level (or a more stringent level) as the result of
State Implementation Plans or New Source Performance Standards. As a result, no
incremental increase for compliance with the PM emission limit is projected.
                                      202

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       The additional costs for interim status compliance reflects the increase in annualized
costs (over a 10 year period) for preparation of the prccompliance and compliance
certification packages (including compliance testing) by approximately 150 Bffs. The
additional cost for the Cl2 standard is based on the incremental cost of analysis for Cl2
beyond that already required to determine HQ emissions.

       The increase in annual recordkeeping, sampling, and analysis costs reflects a
reassessment of the estimated costs in the 1986 analysis. These increased costs reflect a
befbre-tax increase of approximately $2.4 million for recordkeeping and $0.6 million for
sampling and analysis.

       The impact of the 1986 tax code changes was to reduce the marginal tax rate
imposed on before-tax profits  and, thus, has the affect of increasing the impact of
compliance costs on after-tax profits. As a result, the change in the 1986 tax code is to
increase the after-tax cost of the regulations by an estimated $0.6 million per year. The
increase in costs due to inflation reflects an estimated increase in compliance cost of 20
percent between the time of the initial analysis (based on 1985 dollars) and 1990.
                                      203

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                                   TABLE 1
        Cost Element
CO and HC Monitoring
PM Standard
Before Taxes
      1,930,000
After Taxes
     1,200,000
                                 0
Note
Interim Status Compliance

Cl2 Standards


Recordkeeping/Sampling &
Analysis


Tax Code Changes

Inflation
        980,000


         30,000
      3,050,000
              0
      1.640.000
                                       7,630,000
       590,000    3


        20,000    4


     1,700,000    5
       600,000    6
       980.000    7


     5,090,000
Notes:
  1. Based on installing 20 CO monitors using capital and O&M costs from the revised
    ICR.
  2. No incremental costs because BIFs already meet standard by meeting metals limits and
    existing SIP and NSPS limits.
  3. Assumes all not small quantity burner BIFs submit precompliance and compliance
    certification packages, 50% of BIFs submit a revised certification of precompliance,
    and 75% of compliance test can be used in lieu of die trial burn to obtain an operating
    permit, thus reducing the cost of the Part B permit
  4. Assumes all BIFs complying with emissions limits (and not Tier I feed rate limits)
    conduct O2 testing during compliance certification and trial burn tests ($165/sample).
  S. Increases waste sampling and analysis costs  over those estimated at proposal tor all
    non-small quantity burners by $300/month. Provides an  additional 16 hours per
    month for all non-small quantity burners and 2 hours per month for small quantity
    burners for additional recordkeeping.
  6. The 1986 revisions to die Federal tax code reduced the Federal marginal tax rate
    (MTR) from 48% to 34%. The 1986 analysis assumed a MTR of 50% (48% Federal
     Shis 2% State). The revised analysis assumes a MTR of 40% (34% Federal plus 6%
     tate).
  7. Adjustment for 20% inflation between 1985 and 1990 ($8.2 million before tax cost
    estimate in 1985 dollars, adjusted to after-tax basis assuming a marginal tax rate of
    40%.
                                      204

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B. Regulatory Flexibility Act

      The Regulatoiy Flexibility Act (RFA) requires Federal regulatory agencies to
evaluate the impacts of regulations on small entities. The RFA requires an initial screening
analysis to determine whether the proposed rule will have a significant impact on a
substantial number of small businesses.  As indicated at proposal (52 FR 17030), the
Agency estimates that a substantial number of small entities will not be significantly
impacted by the rule. Although the Agency estimates that changes to the rule since
proposal and re-evaluation of some cost estimates made during the initial impact analysis
will result in a higher cost to the regulated industry, the Agency continues to believe that a
substantial number of small entities will not be significantly impacted by the rule.

C. Paperwork Reduction Act

      The information collection requirements in this rule have been submitted for
approval to the Office of Management and Budget (OMB) under the Paperwork Reduction
Act44VS.C.35Qletseq.
ID.  List of Subjects

      Administrative practices and procedures, Confidential business information,
Hazardous materials transportation, Hazardous  waste, Indian lands, Insurance,
Intergovernmental relations, Packaging and containers, Penalties, Recycling, Reporting
and recordkeeping requirements, Security measures, Security bonds, Water pollution
control, Water supply.
F. Henry Habicht, H
Deputy Administrator AND
  ACTING ADMINISTRATOR
                                     205

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 PART 260-HAZARDOUS WASTE MANAGEMENT SYSTEM:  GENERAL

       I. In Part 260:

       1. The authority citation for Pan 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. Section  260.10 is amended by: (1) revising the introductory sentence; (2)
 revising the definition of "incinerator"; (3) revising the definition of "industrial furnace" by
 revising the introductory text and redesignating paragraph (12) as (13) and by adding new
 paragraph (12); and (4) adding, in alphabetical order, definitions for "carbon regeneration
 unit', "infrared incinerator", "plasma arc incinerator" and "sludge dryer" to read as follows:

  260.10   Definitions.

       When used in Parts 260 through 266 and 268 of this chapter, the following terms
 have the meanings given below:
       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, sludge dryer, or carbon 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 accompli!'
recovery of materials or energy:
       (12)  Halogen acid furnaces (HAFs) for the production of acid from halogenated
hazardous waste generated by chemical production facilities where the furnace is located on
the site of a chemical production facility, the acid product has a halogen acid content of at
least 3%, the acid product is used in a manufacturing process, and, except for hazardous
waste burned as fuel, hazardous waste fed to die furnace has a minimum halogen content of
20% as-generated.

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      Infrared incinerator means
heaters as a source of radiant heat a
                                 enclosed device that uses electric powered resistance
                                     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.
      Sludge dryer means any enclosed thermal treatment device that is used to dehydrate
sludge and that has a maximum total thermal input, excluding the heating value of the
sludge itself, of 2,500 Btu/lb of sludge treated on a wet-weight basis.
      3. Paragraph (a) of  260.11 is amended by adding the following references in
alphabetical order?
 260.11

      (a)
           References.

             *     *
      U.S. EPA, Guideline on Air Quality Models (Revised) (1986) and Supplement A
(1987), available from the National Technical Information Service (NTIS), 5285 Port
Royal Road, Springfield, VA 22161, (703) 487-4600. The document numbers are: PB86-
245-248 (Guideline) and PB88-150-958 (Supplement A).

      U.S. EPA, Methods Manual for Compliance with the BIF Regulations. December
1990, available from the National Technical Information Service (NTIS), 5285 Port Royal
Road, Springfield, VA 22161, (703) 487-4600. The document number is PB91-120-006.

      U. S. EPA  Screening Procedures for Estimating Air Quality Impact of Stationary
SiMSCS, August 1988, Available from the National Technical Information Service (NTIS),
5285 Port Royal Road, Springfield, VA 22161, (703) 487-4600. The document number is
PB89-159-396.
PART 261-IDENTIFICATION AND LISTING OF HAZARDOUS WASTE

       IL In Part 261:

       1. The authority citation for Pan 261 continues to read as follows:

       Authority: 42 U.S.C 6905,6912(a), 6921,6922, and 6938.

       2. Section 2612 is amended by redrxignating paragraph (dX2) as (dX3) and adding
new paragraph (dX2) to read as follows:

261.2 Definition of solid waste.

*****

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       (d)    *      *      *

       (2) Secondary materials fed to a halogen -acid furnace that exhibit a characteristic of
a hazardous waste or are listed as a hazardous waste as defined in subparts C or D of this
part

       3. Section 261.4 is amended by adding paragraph (a)(10) and revising paragraphs
(b)(4), the first sentence of (b)(7), and (b)(8) to read as follows:

  261.4 Exclusions.

       (a)    *      *      *

       (10) When used as a fuel, coke and coal tar from the iron and steel industry that
contains or is produced from decanter tank tar sludge, EPA Hazardous Waste K087. The
process of producing coke and coal tar from such decanter tank tar sludge in a coke oven is
likewise excluded from regulation.

       (b)    *      *      *

       (4) Fly ash waste, bottom ash waste, slag waste, and flue gas emission control
waste, generated primarily from the combustion of coal or other fossil fuels, except as
provided by 266.112 of this chapter for facilities that bum or process hazardous waste.
       (7) Solid waste from the extraction, beneficiation, and processing of ores and
minerals (including coal, phosphate rock and overburden from the mining of uranium ore),
except as provided by 266.112 of this chapter for facilities that burn or process hazardous
waste.
      (8) Cement kiln dust waste, except as provided by 266.112 of this chapter for
facilities mat bum or process hazardous waste.
      4. Section 261.6 is amended by deleting paragraph (a)(3)(vii) and renumbering
paragraphs (a)(3Xviu) and (ix) as (aX3Xvii) and (vui) respectively.

PART   264-STANDARDS  FOR  OWNERS  AND  OPERATORS  OF
HAZARDOUS  WASTE  TREATMENT,  STORAGE,  AND DISPOSAL
FACILITIES

      ffl. In Pan 264:

      1. The authority citation far Pan 264 continues to read as follows:

      Authority: 42 U.S.C 6905,6912(a), 6924, and 6925.

      2.  264.112 is amended by revising paragraph (d)(l) to read as follows:
                                \

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 264.112  Closure of plan; amendment of plan.
      (d) Notification of partial closure and final closure.  (1) The owner or operator must
notify the Regional Administrator in writing at least 60 days prior to the date on which he
expects to begin closure of a surface impoundment, waste pile, land treatment or landfill
unit, or final closure of a facility with such a unit The owner or operator must notify the
Regional Administrator in writing at least 45 days prior to the date on which he expects to
begin final closure of a facility with only treatment or storage tanks, container storage, or
incinerator units to be closed.  The owner or operator must notify the Regional
Administrator in writing at least 45 days prior to the date on which he expects to begin
partial or final closure of a boiler or industrial furnace, whichever is earlier.
      3.  264.340 is amended by revising paragraph (a) to read as follows:

  264.340 Applicability.

      (a) The regulations of this subpan apply to owners and operators of hazardous
waste incinerators (as defined in  260.10 of this chapter), except as  264.1 provides
otherwise.
PART  265--INTERIM  STATUS  STANDARDS  FOR  OWNERS  AND
OPERATORS OF HAZARDOUS WASTE  TREATMENT, STORAGE, AND
DISPOSAL FACILITIES

      IV. In Part 265:

      1. The authority citation for Part 265 continues to read as follows:

      Authority:  42 U.S.C. 6905, 6912(a), 6924,6925, and 6935.

      2   265.112 is amended by revising paragraphs (a), (d)(l), and (d)(2) to read as
follows:

 265.112  Closure plan; amendment  of plan.

      (a) Written plan.  By May 19,1981, or by six months after the effective date of the
rule that first subjects a facility to provisions of this section, the owner or operator of a
hazardous waste management facility must have a written closure plan. Until final closure
is completed and certified in accordance with 265.115, a copy of the most current plan
must be furnished to the Regional Administrator upon request, including request by mail.
In addition, for facilities without approved plans, it must also be provided during site
inspections, on die day of inspection, to any officer, employee, or representative of the
Agency who is duly designated by the Adminis
illustrator

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        (d) Notification of partial closure and final closure. (1) The owner or operator must
 submit the closure plan to the Regional Administrator at least 180 days prior to the date on
 which he expects to begin closure of the first surface impoundment, waste pile, land
 treatment, or landfill unit, or final closure if it involves such a unit, whichever is earlier.
 The owner or operator must submit the closure plan to the Regional Administrator at least
 45 days prior to the date on which he expects to begin partial or final closure of a boiler or
 industrial furnace. The owner or operator must submit the closure plan to the Regional
 Administrator at least 45 days prior to the date on which he expects to begin final closure of
 a facility with only tanks, container storage, or incinerator units. Owners or operators with
 approved closure plans must notify the Regional Administrator in writing at least 60 days
 prior to the date on which he expects to begin closure of a surface impoundment, waste
 pile, landfill, or land treatment unit, or final closure of a facility involving such a unit
 Owners or operators with approved closure plans must notify the Regional Administrator in
 writing at least 45 days prior to the date on which he expects to begin partial or final closure
 of a boiler or industrial furnace. Owners or operators with approved closure plans must
 notify the Regional Administrator in writing at least 45 days prior to the date on which he
 expects to begin final closure of a facility with only tanks, container storage, or incinerator
 units.

       (2) Except for boilers and industrial furnaces that operate under interim status as
 specified by 266.103(c)(7)(i)(B) or (C), the date when he "expects to begin closure" must
 be either within 30 days after the date on which any hazardous waste management unit
 receives the known final volume  of hazardous  wastes, or, if there is a reasonable
 possibility that the hazardous waste management unit will receive additional hazardous
 wastes, no later than one year after the date on which the unit received the most recent
 volume of hazardous waste.  If the owner or operator of a hazardous waste management
 unit can demonstrate to the Regional Administrator that the hazardous waste management
 unit or facility has the capacity to receive additional hazardous wastes and he has taken, and
 will continue to take, all steps to prevent threats to human health and the environment,
 including compliance with all interim status requirements, the Regional Administrator may
 approve an extension to this one-year limit For boilers and industrial furnaces that operate
 under interim status as  specified by   266.103(c)(7)(i)(B) or (C), the date when he
 "expects to begin closure" must be within 30 days after failure to submit a complete
 certification of compliance by the applicable deadline under  266.103(cX7)(i)(B) or (C).
       3 265.113 is amended by revising paragraphs (a) and (b) to read as follows:

  265.113   Closure; time allowed for closure.

       (a)  Within 90 days after receiving the final volume of hazardous wastes at a
hazardous waste management unit or facility, or within 90 days after approval of the
closure plan, whichever is later, or, for a boiler or industrial furnace that does not submit a
complete certification of compliance by the applicable deadline under 266.103(cX7Xi)(B)
or (C), within 90 days after the applicable deadline, the owner or operator must treat,
remove from the unit or facility  or dispose of on-site, all hazardous wastes in accordance
with the approved closure plan. The Regional Administrator may approve a longer period
if the owner or operator demonstrates that:

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      (b) The owner or operator must complete partial and final closure activities in
accordance with the approved closure plan and within 180 days after receiving the final
volume of hazardous wastes at the hazardous waste management unit or facility, or 180
days after approval of the closure plan, if that is later, or, for a boiler or industrial furnace
mat does not submit a complete certification of compliance by the applicable deadline under
 266.103(c)(7)(i)(B) or (Q, within 180 days after the applicable deadline. The Regional
Administrator may approve an extension to the closure period if the owner or operator
demonstrates mat:
      4.  265.340 is amended by revising paragraph (a) to read as follows:

  265.340 Applicability.

      (a) The regulations of this subpart apply to owners and operators of hazardous
waste incinerators (as defined in  260.10 of this chapter), except as  265.1 provides
otherwise.
PART  266--STANDARDS  FOR  THE  MANAGEMENT  OF  SPECIFIC
HAZARDOUS  WASTES  AND  SPECIFIC  TYPES  OF  HAZARDOUS
WASTE MANAGEMENT FACILITIES

      V.InPart266:

      1. The authority citation for Pan 266 continues to read as follows:

      Authority:  Sees. 1006, 2002(a), 3004. and 3014 of the Solid Waste Disposal
Act, as amended by the Resource Conservation and Recovery Act of 1976, as amended (42
U.S.C. 6905, 6912(a), 6924, and 6934).

      2. Subpart D is hereby removed and reserved and Subpart H is added to read as
follows:

Subpart H - Hazardous Waste Burned in Boilers and Industrial Furnaces
Sec.
 266.100
 266.101
266.102
 266.103
 266.104
 266.105
 266.106
266.107

 266.108
 266.109
 266.110
266.111
Applicability.
Management prior to burning.
Permit standards for burners.
Interim status standards for burners.
Standards to control organic emissions.
Standards to control paniculate matter.
Standards to control metals emissions.
Standards to control hydrogen chloride (HC1) and chlorine gas (Cl2)
emissions.
Small quantity burner exemption.
Low risk waste exc
Automatic waiver of DUE trial bum for boilers.
Standards for direct transfer.

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266.112    Regulation of residues.

  266.100  -  Applicability.

       (a) The regulations of this subpan apply to hazardous waste burned or processed in
a boiler or industrial furnace (as defined in 260.10 of this chapter) irrespective of the
purpose of burning or processing, except as provided by paragraphs (b). (c), and (d) of
this section.  In this subpart, the term "burn"  means burning for energy recovery or
destruction, or processing for materials recovery or as an ingredient.  The emissions
standards of 266.104, 266.105, 266.106, and 266.107 apply to facilities operating
under interim status or under a  RCRA operating permit as specified in 266.102 and
266.103.

       (b) The following hazardous wastes and facilities are not subject to regulation under
this subpan:

       (1) Used oil burned for  energy  recovery that is also a hazardous waste solely
because it exhibits a characteristic of hazardous waste identified in Subpan C of Pan 261 of
this chapter. Such used oil is subject to regulation under Subpan E of Pan 266 rather than
this subpan;

       (2) Gas recovered from hazardous or solid waste landfills when such gas is burned
for energy recovery.

       (3) Hazardous wastes that  are exempt from  regulation under 261.4 and
261.6(a)(3)(v - viii) of this chapter, and hazardous wastes that are subject to the special
requirements for conditionally exempt small quantity generators under  261.5 of this
chapter.

       (4) Coke ovens, if the only hazardous waste burned is EPA Hazardous Waste No.
K087, decanter tank tar sludge from coking operations.

       (c) Owners and operators of smelting, melting, and refining furnaces (including
pyrometallurgical devices such as cupolas, sintering machines, roasters, and foundry
furnaces, but not including cement kilns,  aggregate kilns, or halogen acid furnaces burning
hazardous waste) that process hazardous waste solely for metal recovery are conditionally
exempt from regulation under this subpan, except for 266.101 and 266.112.

       (1) To be exempt from 266.102 through 266.111, an owner or operator must:

       (i) Provide a one-time written notice to the Director indicating the following:

       (A) The owner or operator claims exemption under this paragraph;

       (B) The hazardous waste is burned  solely for metal recovery consistent with the
provisions of paragraph (c)(2) of this section;

       (C) The hazardous waste contains recoverable levels of metals; and

       (D) The  owner or operator  will comply with the  sampling and analysis and
recordkeeping requirements of this paragraph;

       (u) Sample and analyze the hazardous waste and other feedstocks as necessary to
comply with the requirements  of this  paragraph under procedures specified by Test

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Methods for Evaluating Solid Waste. Physical/Chemical Methods. SW-846, incorporated
by reference in 260.11 of this chapter, and

       (iii) Maintain at the facility for at least three years records to document compliance
with the provisions of mis paragraph including limits on levels of toxic .organic constituents
and Btu value of the waste, and levels of recoverable metals in the hazardous waste
compared to normal nonhazardous waste feedstocks.

       (2) A hazardous waste meeting either of the following criteria is not processed
solely for metal recovery:

       (i) The hazardous waste has a total concentration of organic compounds listed in
Pan 261, Appendix VDI, of this chapter exceeding 500 ppm by weight, as-generated, and
so is considered to be burned for destruction; or

       (ii) The hazardous waste has a heating value of 5,000 Btu/lb or more, as-generated
or as-fired into the furnace, and so is considered to be burned as fuel

       (d) The standards for direct transfer operations under 266.111 apply only to
facilities subject to the permit standards of 266.102 or the interim status standards of
266.103.

       (e) The management standards for residues under 266.112 apply to any boiler or
industrial furnace burning hazardous waste.

(Approved by the Office of Management and Budget under control number	)

 266.101 -  Management prior to  burning.

       (a) Generators. Generators of hazardous waste that is burned in a boiler or
industrial furnace are subject to Pan 262 of mis chapter.

       (b) Transporters. Transporters of hazardous waste that is burned in a boiler or
industrial furnace are subject to Pan 263 of this chapter.

       (c) Storage facilities. (1) Owners and operators of facilities that store hazardous
waste that is burned in a boiler or industrial furnace are subject to the applicable provisions
of Subpans A through L of Pan 264, Subpans A through L of Pan 265, and Pan 270 of
this chapter, except as provided by paragraph (c)(2) of this section. These standards apply
to storage by the burner as well as to storage facilities operated by intermediaries
(processors, blenders, distributors, etc.) between the generator and the burner.

       (2) Owners and operators of facilities  that bum, in an on-site boiler or industrial
furnace exempt from regulation under the small quantity burner provisions of  266.108,
hazardous waste that they generate are exempt from regulation under Subpans A through L
of Pan 264, Subpans A through L of Pan 265, and Pan 270 of this chapter with respect to
the storage of mixtures of hazardous waste and the primary fuel to the boiler or industrial
furnace in tanks that feed the fuel mixture directly to the burner.  Storage of hazardous
waste prior to mixing with the primary fuel is subject to regulation as prescribed in
paragraph (cXl) of mis section.

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  266.102 - Permit standards for burners.

       (a) Applicability. (1) General,  Owners and operators of boilers and industrial
furnaces burning hazardous waste and not operating under interim status must comply with
the requirements of this section and  270.22 and 270.66 of this chapter, unless exempt
under the small quantity burner exemption of  266.108.

       (2) Applicability of Part 264 standards.  Owners and operators of boilers and
industrial furnaces that bum hazardous waste are subject to the following provisions of Pan
264 of mis chapter, except as provided otherwise by this subpart:

       (i) In Subpart A (General),  264.4;

       (ii) In Subpart B (General facility standards),  264.11-264.18;

       (iii) In Subpart C (Preparedness and prevention),  264.31-264.37;

       (iv) In Subpart D (Contingency plan and emergency procedures),  264.51-
264.56;

       (v) In Subpart E (Manifest system, recordkeeping, and reporting), the applicable
provisions of  264.71-264.77;

       (vi) In Subpart F (Corrective Action),  264.90 and 264.101;

       (vii) In Subpart G (Closure and post-closure),  264.111 - 264.115;

       (viii) In Subpart H (Financial requirements),  264.141,264.142,264.143, and
264.147-264.151, except that States and the Federal government are exempt from the
requirements of Subpart H; and

       (ix) Subpart BB (Air emission  standards for equipment  leaks), except
264.1050(a).

       (b) Hazardous waste analysis.  (1) The owner or operator must provide an analysis
of tite hazardous waste that quantifies the concentration of any constituent identified in
Appendix VHI of Pan 261 of this chapter that may reasonably be expected to be in the
waste.  Such constituents must be identified and quantified if present, at levels detectable
by analytical procedures prescribed by Test Methods for the Evaluation of Solid Waste.
Physical/ Chemical Methods (incorporated by reference, see 260.11 of this chapter). The
Appendix VTfl, Pan 261 constituents excluded from this analysis must be identified and the
basis for their exclusion explained. This analysis will be used to provide all information
required by this subpart and  270.22 and  270.66 of this chapter and to enable the permit
writer to prescribe such permit conditions as necessary to protect human health and the
environment.  Such analysis must be included as a portion of the Pan B permit application,
or, for facilities operating under the interim status standards of this subpart, as a portion of
the trial bum plan that may be submitted before the Pan B application under provisions of
270.66(g) of this chapter as well as any other analysis required by the permit authority in
preparing the permit Owners and operators of boilers and industrial furnaces not operating
under the interim status standards must provide the information required by 270.22 or
270.66(c) of mis chapter in the Pan B application to the greatest extent possible.

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      (2) Throughout normal operation, the owner or operator must conduct sampling
and analysis as necessary to ensure that the hazardous waste, other fuels, and industrial
furnace feedstocks fired into the boiler or industrial furnace are within the physical and
chemical composition limits specified in the permit

      (c) Emissions standards. Owners and operators must comply with emissions
standards provided by  266.104 through 266.107.

      (d) Permits. (1) The owner or operator may burn only hazardous wastes specified
in the facility permit and only under the operating conditions specified under paragraph (e)
of this section, except in approved trial bums under the conditions specified in  270.66 of
this chapter.

      (2) Hazardous wastes not specified in the permit may not be burned until operating
conditions have been specified under a new permit or permit modification, as applicable.
Operating requirements  for new wastes may be based on either trial burn results or
alternative data included with Part B of a permit application under 270.22 of this chapter.

      (3) Boilers and industrial furnaces operating under the interim status standards of
266.103 are permitted under procedures provided by 270.66(g) of this chapter.

      (4) A permit for a new boiler or industrial furnace (those boilers and industrial
furnaces not operating under  the interim status standards) must establish  appropriate
conditions for each of the applicable requirements of this section, including but not limited
to allowable hazardous waste firing rates and operating conditions necessary to meet the
requirements of paragraph (e) of this section, in order to comply with the following
standards:

      (i) For the period beginning with initial introduction of hazardous waste and ending
with initiation of the trial burn, and only for the minimum time required to bring the device
to a point of operational readiness to conduct a trial bum, not to exceed  a duration of 720
hours operating time when burning hazardous waste, the operating requirements must be
those most likely to ensure compliance with the emission standards of  266.104 through
266.107, based on the Director's engineering judgment If the  applicant is seeking a
waiver from a trial burn to demonstrate conformance with a particular emission standard,
the operating requirements during this initial  period of operation shall include those
specified by the applicable provisions of 266.104, 266.105, 266.106, or 266.107.
The Director may extend the duration of this period for up to 720 additional hours when
good cause for the extension is demonstrated by the applicant

      (ii) For the duration of the trial bum, the operating requirements must be sufficient
to demonstrate compliance with the emissions standards of  266.104 through 266.107
and must be in accordance with the approved trial burn plan;

      Oii) For the period immediately following completion of the trial bum, and only for
the minimum period sufficient to allow sample analysis, data computation, submission of
the trial bum results by me applicant, review of the trial bum results and modification of the
facility permit by the Director to reflect the trial burn results, the  operating requirements
must be those most likely to ensure compliance with the emission standards of  266.104
through 266.107 based on the Director's engineering judgment

       (D) For the remaining duration of the permit, the operating requirements must be
those demonstrated in a trial  burn or by alternative data specified in  270.22 of this
                                       10

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chapter, as sufficient to ensure compliance with the emissions standards of  266.104
through 266.107.

       (e) Operating requirements. (1) General. A boiler or industrial furnace burning
hazardous waste must be operated in accordance with the operating requirements specified
in the permit at all times when there is hazardous waste in the unit

       (2) Requirements to ensure compliance with the organic emissions standards,  (i)
ORE standard.  Operating conditions will be specified either on a case-by-case basis for
each hazardous waste burned as those demonstrated (in a trial bum or by alternative data as
specified in  270.22) to  be  sufficient to  comply with the  destruction and removal
efficiency (DRE) performance standard of    266.104(a) or as those special operating
requirements provided by 266.104(a)(4) for the waiver of the DRE trial burn.  When the
DRE trial bum is not waived under 266.104(a)(4), each set of operating requirements will
specify the composition of the hazardous waste (including acceptable variations in the
physical and chemical properties of the hazardous waste which will not affect compliance
with the DRE performance standard) to which the operating requirements apply. For each
such hazardous waste, die permit will specify acceptable operating limits including, but not
limited to, the following conditions as appropriate:

       (A) Feed rate of hazardous waste and other fuels measured and specified as
prescribed in paragraph (e)(6) of this section;

       (B) Minimum and  maximum device production rate when producing normal
product expressed in appropriate units, measured and specified as prescribed in paragraph
(e)(6) of this section;

       (C) Appropriate controls of the hazardous waste firing system;

       (D) Allowable variation in boiler and industrial furnace system design or operating
procedures;

       (E) Minimum combustion gas temperature measured at a location indicative of
combustion chamber temperature, measured and specified as prescribed in paragraph (e)(6)
of this section;

       (F) An appropriate indicator of combustion gas velocity, measured and specified as
prescribed in paragraph (e)(6) of this section, unless documentation is provided under
270.66 of this chapter demonstrating adequate combustion gas residence time; and

       (G) Such other operating requirements as are necessary to ensure that the DRE
performance standard of  266.104(a) is met

       (ii) Carbon monoxide and hydrocarbon standards. The permit must incorporate a
carbon monoxide (CO) limit and, as appropriate, a hydrocarbon (HC) limit as provided by
paragraphs (b), (c), (d), (e) and (f) of 266.104.  The permit limits will be specified as
follows:

       (A) When complying with the CO standard of 266.104(b)(l), the permit limit is
lOOppmv;

       (B) When complying with the alternative CO standard  under 266.104(c), the
permit limit for CO is based on the trial burn and is established as the average over all valid
                                      11

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runs of the highest hourly rolling average CO level of each run, and the permit limit for HC
is 20 ppmv (as defined in 266.104(c)(l)), except as provided in 266.104(0.

      (C) When complying with the alternative HC limit for industrial furnaces under
266.104(f), the permit limit for HC and CO is the baseline level when hazardous waste is
not burned as specified by that paragraph.

      (iii) Start-up and shut-down.  During start-up and shut-down of the boiler or
industrial furnace, hazardous waste (except waste fed solely as an ingredient under the Her
I (or adjusted Tier I) feed rate screening limits for metals and chloride/chlorine, and except
low risk waste exempt from the trial burn requirements under 266.104(a)(5), 266.105,
266.106, and 266.107) must not be fed into the device unless the device is operating within
the conditions of operation specified in Ac permit

      (3) Requirements to ensure conformance with the paniculate standard, (i) Except as
provided in paragraphs (e)(3)(ii) and (iii) of this  section, the permit shall specify the
following operating requirements to ensure conformance with the paniculate standard
specified in  266.105:
       (A) Total ash feed rate to the device from hazardous waste, other fuels, and
industrial furnace feedstocks, measured and specified as prescribed in paragraph (e)(6) of
this section;

       (B) Maximum device production rate when producing normal product expressed in
appropriate units, and measured and specified as prescribed in paragraph (e)(6) of this
section;

       (Q Appropriate controls on operation and maintenance of the hazardous waste
firing system and any air pollution control system;

       (D) Allowable variation in boiler and industrial furnace system design including any
air pollution control system or operating procedures; and

       (E) Such other operating requirements as are necessary to ensure that die paniculate
standard in  266.1 1 l(b) is met

       (ii) Permit conditions to ensure conformance with the paniculate matter standard
shall not be provided for facilities exempt from the paniculate matter standard under
266.105(b);
        ii) For cement kilns and light-weight aggregate kilns, permit conditions to ensure
compliance with the paniculate standard shall not limit the ash content of hazardous waste
or other feed
       (4) Requirements to ensure conformance with the metals emissions standard,  (i)
For conformance with the Tier I (or adjusted Tier I) metals feed rate screening limits of
paragraphs (b) or (e) of  266.106, the permit shall specify the following operating
requirements:

       (A) Total feed rate of each metal in hazardous waste, other fuels, and industrial
furnace feedstocks measured and specified under provisions of paragraph (e)(6) of this
section;
                                       12

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       (B) Total feed rate of hazardous waste measured and specified as prescribed in
 paragraph (e)(6) of this section;
       (Q A sampling and metals analysis program for the hazardous waste, other fuels,
 and industrial furnace feedstocks;
       (ii) For conformance with the Tier n metals emission rate screening limits under
 266.106(c) and the Tier HI metals controls under  266.106(d), the permit shall specify
 the following operating requirements:
       (A) Maximum emission rate for each metal specified as the average emission rate
 during the trial bum;
       (B) Feed rate of total hazardous waste and pumpable hazardous waste, each
 measured and specified as prescribed in paragraph (e)(6)(i) of this section;
       (C) Feed rate of each metal in the following feedstreams, measured and specified as
 prescribed in paragraphs (e)(6) of this section:
       (1) Total feed streams;
       (2) Total hazardous waste feed; and
       (5) Total pumpable hazardous waste feed;
       (D) Total feed rate of chlorine and chloride in total feed streams measured and
 specified as prescribed in paragraph (e)(6) of this section;
       (E) Maximum combustion gas temperature measured at a location indicative of
 combustion chamber temperature, and measured and specified as prescribed in paragraph
 (e)(6) of this section;
       (F) Maximum flue gas temperature at the inlet to the paniculate matter air pollution
 control system measured and specified as prescribed in paragraph (e)(6) of this section;
       (G) Maximum device production rate when producing normal product expressed in
 appropriate units and measured and specified as prescribed in paragraph (e)(6)  of this
 section;
       (H) Appropriate controls on operation and maintenance of the hazardous waste
 firing system and any air pollution control system;
       (I) Allowable variation in boiler and industrial furnace system design including any
 air pollution control system or operating procedures; and
       (I) Such other operating requirements as are necessary to ensure that the metals
 standards under  266.106(c) or 266.106(d) are met
       (iii) For conformance with an alternative implementation approach approved by the
Director under 266.106(f), the permit will specify the following operating requirements:
       (A) Maximum emission rate for each metal specified as the average emission rate
 during the trial burn;
                                      13

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       (B) Feed rate of total hazardous waste and pumpable hazardous waste, each
measured and specified as prescribed in paragraph (e)(6)(i) of this section;

       (Q Feed rate of each metal in the following feedstreams, measured and specified as
prescribed in paragraph (e)(6) of this section:

       (/) Total hazardous waste feed; and

       (2) Total pumpable hazardous waste feed;

       (D) Total feed rate of chlorine and chloride in total feed streams measured and
specified as prescribed in paragraph (e)(6) of this section;

       (E) Maximum combustion gas temperature measured at a location indicative of
combustion chamber temperature, and measured and specified as prescribed in paragraph
(e)(6) of mis section;

       (F) Maximum flue gas temperature at the inlet to the paniculate matter air pollution
control system measured and specified as prescribed in paragraph (e)(6) of this section;

       (G) Maximum device production rate when producing normal product expressed in
appropriate units and measured and specified as prescribed in paragraph (e)(6) of this
section;

       (H) Appropriate controls on operation and maintenance of the hazardous waste
firing system and any air pollution control system;

       (I) Allowable variation in boiler and industrial furnace system design including any
air pollution control system or operating procedures; and

       (J) Such other operating requirements as are necessary to ensure that the metals
standards under  266.106(c) or 266.106(d) are met

       (S) Requirements to ensure conformance with the hydrogen chloride and chlorine
gas standards,  (i) For conformance with the Tier I total chloride and chlorine feed rate
screening limits of   266.107(b)(l), the permit will specify the following  operating
requirements:

       (A) Feed rate of total chloride and chlorine in hazardous waste, other fuels, and
industrial furnace feedstocks measured and specified as prescribed in paragraph (e)(6) of
this section;

       (B) Feed rate of total hazardous waste measured and specified as prescribed in
paragraph (eX6) of this section;

       (C) A sampling and analysis program for total chloride and chlorine for the
hazardous waste, other fuels, and industrial furnace feedstocks;

       (ii) For conformance with the Tier IIHQ and Q2 emission rate screening limits
under 266.107(bX2) and the Tier m HQ and Cfe controls under  266.107 (c), the permit
wfll specify the following operating requirements:
                                       14

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       (A) Maximum emission rate for Hd and for Q2 specified as the average emission
 rate daring the trial bum;

       (B) Feed rate of total hazardous waste measured and specified as prescribed in
 paragraph (e)(6) of this section;

       (C) Total feed rate of chlorine and chloride in total feed streams, measured and
 specified as prescribed in paragraph (e)(6) of this section;

       (D) Maximum device production rate when producing normal product expressed in
 appropriate units, measured and specified as prescribed in paragraph (e)(6) of this section;

       (E) Appropriate controls on operation and maintenance of the hazardous waste
 firing system and any air pollution control system;

       (F) Allowable variation in boiler and industrial furnace system design including any
 air pollution control system or operating procedures; and

       (G) Such other operating requirements as are necessary to ensure that the HC1 and
 Cl2 standards under 266.107(b)(2) or (c) are met

       (6) Measuring parameters and establishing limits based on trial burn data, (i)
 General requirements. As specified in paragraphs (e)(2) through (e)(5) of this section,
 each operating parameter shall be measured, and permit limits on the parameter shall be
 established, according to either of the following procedures:

       (A) Instantaneous limits.  A parameter may be measured and recorded on an
 instantaneous basis (i.e., the value that occurs at any time) and the permit limit specified as
 the time-weighted average during all valid runs of the trial bum; or

       (B) Hourly rotting average. (/) The limit for a parameter may be established and
 continuously monitored on an hourly rolling average basis defined as follows:

       (0 A continuous monitor  is one  which continuously samples the regulated
 parameter without interruption, and evaluates the detector response at least once each 15
 seconds, and computes and records the average value at least every 60 seconds.

       (i'0 An hourly rolling average is the arithmetic mean of the 60 most recent 1-minute
 average values recorded by the continuous monitoring system.

       (2) The permit limit for the parameter shall be established based on trial bum data as
 the average over all valid test runs of the highest hourly rolling average value for each run.

       (ii) Rolling average limits for carcinogenic metals and lead. Feed rate limits for the
carcinogenic metals (Le., arsenic, beryllium, cadmium and chromium) and lead may be
established either on an hourly rolling average basis as prescribed by paragraph (cK6)(i) of
this section or on (up to) a 24 hour rolling average basis. If the owner or operator elects to
use an averaging period of from 2 to 24 hours:

       (A) The feed rate of each metal shall be limited at any time to ten times the f eedrate
mat would be allowed on a hourly rolling average basis;
                                       IS

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       (B) The continuous monitor shall mfttt the following spccifi
       (/) A continuous monitor is one which continuously samples the regulated
parameter without interruption, and evaluates the detector response at least once each IS
seconds, and computes and records the average value at least every 60 seconds.

       (2) The rolling average for the selected averaging period is defined as the arithmetic
mean of die most recent one hour block averages for the averaging period. A one hour
block average is the arithmetic mean of the one minute averages recorded during die 60-
minute period beginning at one minute after die beginning of preceding clock hour, and

       (Q The permit limit for the feed rate of each metal shall be established based on trial
burn data as the average over all valid test runs of the highest hourly rolling average feed
rate for each run.

       (iii) Feed rate Kmitsfor metals, total chloride and chlorine, and ash. Feed rate limits
for metals, total chlorine and chloride, and ash are established and monitored by knowing
the concentration of the substance (i.e., metals, chloride/chlorine, and ash) in each
feedstream and the flow rate of the feedstream. To monitor die feed rate of these
substances, the flow rate of each feedstream must be monitored under die continuous
monitoring requirements of paragraphs (e)(6)(i) and (ii) of this section.

       (iv) Conduct of trial burn testing.  (A) If compliance with all applicable emissions
standards of 266.104 through 266.107 is not demonstrated simultaneously during a set
of test runs, the operating conditions of additional test runs required to demonstrate
compliance with remaining emissions standards must be as close as possible to die original
operating conditions.

       (B) Prior to obtaining test data for purposes of demonstrating compliance with the
emissions standards of 266.104 through 266.107 or establishing limits on operating
parameters under this section, the facility must operate under trial bum conditions for a
sufficient period to reach steady-state operations. The Director may determine, however,
that industrial furnaces that recycle collected paniculate matter back into the furnace and that
comply with an alternative implementation approach for metals under 266.106(f), need
not reach steady state conditions with respect to the flow of metals in the system prior to
beginning compliance testing for metals emissions.

       (C) Trial bum data on the level of an operating parameter for which a limit must be
established in the permit must be obtained during emissions sampling for the pollutant(s)
(i.e.,  metals, PM, HC1/C12, organic compounds) for which the parameter must be
established as specified by paragraph (e) of this section.

       (7) General requirements,  (i) Fugitive emissions. Fugitive emissions must be
controlled by:

       (A) Keeping the combustion zone totally sealed against fugitive emissions; or

       (B) Maintaining the combustion zone pressure lower than atmospheric pressure; or

       (C) An  alternate means of control demonstrated (with Part B of the permit
application) to provide fugitive emissions control equivalent to maintenance of combustion
zone pressure lower than atmospheric pressure.
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       (ii) Automatic waste feed cutoff. A boiler or industrial furnace must be operated
with a functioning system that automatically cuts off the hazardous waste feed when
operating conditions deviate from those established under this section. The Director may
limit the number of cutoffs per an operating period on a case-by-case basis.  In addition:

       (A) The permit limit for (the indicator of) minimum combustion chamber
temperature must be maintained while hazardous waste or hazardous waste residues remain
in the combustion chamber,

       (B) Exhaust gases must be ducted to the air pollution control system operated in
accordance with the permit requirements while hazardous waste or hazardous waste
residues remain in the combustion chamber, and

       (C) Operating parameters for which permit limits are established must continue to
be monitored during the cutoff, and the hazardous waste feed shall not be restarted until the
levels of those parameters comply with the permit limits. For parameters that may be
monitored on an instantaneous basis, the Director will establish a minimum period of time
after a waste feed cutoff during which the parameter must not exceed the permit limit before
the hazardous waste feed may be restarted.

       (iii) Changes. A boiler or industrial furnace must cease  burning hazardous waste
when changes in combustion properties, or feed rates  of the hazardous waste, other fuels,
or industrial furnace feedstocks, or changes in the boiler or industrial furnace design or
operating conditions deviate from the limits as specified in the permit

       (8) Monitoring and Inspections,  (i) The owner  or operator must monitor and record
the following, at a minimum, while burning hazardous  waste:
                                                                    i waste, other
fuels, and industrial furnace feedstocks, and feed rates of ash, metals, and total chloride
and chlorine;

       (B) If specified by the permit, carbon monoxide (CO), hydrocarbons (HC), and
oxygen on a continuous basis at a common point in the boiler or industrial furnace
downstream of the combustion zone and prior to release of stack gases to the atmosphere in
accordance with operating requirements specified in paragraph (e)(2)(ii) of this section.
CO, HC, and oxygen monitors must be installed, operated, and maintained in accordance
with methods  specified in Methods  Manual for Compliance with the BIF Regulations
(incorporated by reference, see  260.11).
       (C) Upon the request of the Director, sampling and analysis of the hazardous waste
(and other fuels and industrial furnace feedstocks as appropriate), residues, and exhaust
emissions must be conducted to verify that the operating requirements established in the
permit achieve the applicable standards of  266.104,266.105,266.106, and 266.107.

       (ii) All monitors shall record data in units corresponding to the permit limit unless
otherwise specified in the permit

       (iii) The boiler or industrial furnace and associated equipment (pumps, valves,
pipes, fuel storage tanks, etc.) must be subjected to thorough visual inspection when it
contains hazardous waste, at least daily for leaks, spills, fugitive emissions, and signs of
tampering.
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       (iv) The aiifrTMtfc hazardous waste feed cutoff system and associated alarms must
be tested at least once every 7 days when hazardous waste is burned to verify operability,
unless the applicant demonstrates to the Director mat weekly inspections will unduly restrict
or upset operations and that less frequent inspections will be adequate.  At a minimum,
operational testing must be conducted at least once every 30 days.

       (v) These monitoring and inspection data must be recorded and the records must be
placed in the operating record required by 264.73 of this chapter.

       (9) Direct transfer to the burner. If hazardous waste is directly transferred from a
transport vehicle to a boiler or industrial furnace  without the use of a storage unit, the
owner and operator must comply with 266. 111.

       (10) Recordkeeping. The owner or operator must keep in the operating record of
the facility all information and data required by this section for not less man three years.

       (11) Closure. At closure, the owner or operator must remove all hazardous waste
and hazardous waste residues (including, but not limited to, ash, scrubber waters, and
scrubber sludges) from the boiler or industrial furnace.

(Approved by the Office of Management and Budget under control number	)
  266.103   Interim status  standards  for owners and operators of facilities
that burn hazardous waste  in a boiler or industrial  furnace.

       (a) Purpose, scope, applicability. (I) General, (i) The purpose of this section is to
establish minimum national standards for owners and operators of "existing" boilers and
industrial furnaces that burn hazardous waste where such standards define the acceptable
management of hazardous waste during the period of interim status. The standards of mis
section apply to owners and operators of existing facilities until either a permit is issued
under  266.102(d) or until closure responsibilities identified in this section are fulfilled.

       (ii) Easting or in existence means a boiler or industrial furnace that on or before
[insert date  6 months after promulgation of this rule] is either in operation burning or
processing hazardous waste or for which construction (including the ancillary facilities to
bum or process the hazardous waste) has commenced.  A facility has commenced
construction if the owner or operator has obtained the Federal, State, and local approvals or
permits necessary to begin physical construction; and either

       (A) A continuous on-site, physical construction program has begun; or

       (B) The owner or operator has entered into contractual obligations-which cannot be
canceled or modified without substantial loss-for physical construction of the facility to be
completed within a reasonable time.
       (iii) If a boiler or industrial furnace is located at a fi
interim status, then die facility must comply with the
mat already has a permit or
      lations dealing with
permit modifications in  270.42 or changes in interim status in 270.72 of this chapter.

       (2) Exemptions. The requirements of this section do not apply to hazardous waste
and facilities exempt under  266.100(b), (c) or 266.108.
                                       18

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       (3) Prohibition on burning dioxin-listed wastes. Hazardous waste listed for dioxin
 or derived from any of the following dioxin-listed wastes may not be burned in a boiler or
 industrial furnace operating under interim status: EPA Hazardous Waste Numbers F020,
 F021, F022, F023, F026, or F027.

       (4) Applicability of Pan 265 standards. Owners and operators of boilers and
 industrial furnaces that burn hazardous waste and are operating under interim status are
 subject to the following provisions of Part 265 of this chapter, except as provided
 otherwise by this section:

       (i) In Subpart A (General), 265.4;

       (ii) In Subpart B (General facility standards), 265.11-265.17;

       (iii) In Subpart C (Preparedness and prevention), 265.31-265.37;

       (iv)  In Subpart D (Contingency plan and emergency procedures), 265.51-
 265.56;

       (v) In Subpart E (Manifest system,  recordkeeping, and repotting), 265.71-
 265.77, except that 265.71, 265.72, and 265.76 do not apply to owners and operators
 of on-site facilities that do not receive any hazardous waste from off-site sources;

       (vi) In Subpart G (Closure and post-closure),  265.111-265.115;

       (vii) In Subpart H (Financial requirements), 265.141, 265.142, 265.143, and
 265.147-265.151,  except that States and the Federal government are exempt from the
 requirements of Subpart H; and

       (viii)  Subpart BB  (Air emission  standards  for equipment leaks), except
 265.1050(a).

       (5) Special requirements for furnaces.  The following controls apply during interim
 status to industrial furnaces (e.g., kilns, cupolas) that feed hazardous waste for a purpose
 other than solely as an ingredient (see paragraph (a)(5)(ii) of this section) at any location .
 other than the hot end where products  are  normally discharged and where fuels are
 normally fired:

       (i) Controls. (A) The hazardous waste shall be fed at a location where combustion
 gas temperatures are at least 1800F;

       (B) The owner or operator must determine that adequate oxygen is present in
combustion gases to combust organic constituents in the waste and retain documentation of
 such determination in the facility record;

       (Q For cement kiln systems, the hazardous waste shall be fed into the kiln; and

       (D) The hydrocarbon controls of 266.104(c) or paragraph (cK7Xii) of this section
apply upon certification of compliance under paragraph (c) of this section irrespective of the
CO level achieved during the compliance test.

       (ii) Burning hazardous waste solely as an ingredient. A hazardous waste is burned
for a purpose other than solely as an ingredient if it meets either of these criteria:
                                       19

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       (A) The hazardous waste has a total concentration of nonmetal compounds listed in
Part 261, Appendix VIII, of this chapter exceeding 500 ppm by weight as-generated (and,
so, is considered to be burned for destruction); or

       (B) The hazardous waste has a heating value of 5,000 BtuAb or more, as-generated
or as-fired (and, so, is considered to be burned as fuel).

       (6) Restrictions on burning hazardous waste that is not a fuel. Prior to certification
of compliance under paragraph (c) of this section, owners and operators shall not feed
hazardous waste (other than hazardous waste burned solely as an ingredient) in a boiler or
industrial furnace that has a heating value less than 5,000 Btu/lb, as-generated, except for
purposes of compliance testing (or testing prior to compliance testing) for a total period of
time not to exceed 720 hours.

       (7) Direct transfer to the burner.  If hazardous waste is directly transferred from a
transport vehicle to a boiler or industrial furnace without the use of a storage unit, the
owner and operator must comply with 266.111.

       (b) Certification of precompliance. (1) General. The owner or operator must
provide complete and accurate information specified in paragraph (b)(2) of this section to
the Director on or before [the effective date of this rule], and must establish limits for the
operating parameters specified in paragraph (b)(3) of this section. Such information is
termed a "certification of precompliance" and constitutes a certification that the owner or
operator has determined mat, when the facility is operated within the limits specified in
paragraph (b)(3) of this section, the owner or operator believes that, using best engineering
judgment, emissions of paniculate matter, metals, and HQ and Q2 are not likely to exceed
the limits  provided by 266.105, 266.106, and  266.107.  The facility may burn
hazardous waste only under the operating conditions that the owner or operator establishes
under paragraph (b)(3) of this section  until the owner or operator submits a revised
certification of precompliance under paragraph (b)(8) of this section or a certification of
compliance under paragraph (c) of this section, or until a permit is issued.

       (2) Information required. The following information must be submitted with the
certification of precompliance to support the determination that the limits established for the
 	..   , parametBrs identified in paragraph (b)(3) are not likely to result in an exceedance
   the allowable emission rates for paniculate matter, metals, and HC1 and Cfr

       (i) General facility information:

       (A) EPA facility ID number,

       (B) Facility name, contact person, telephone number, and address;

       (Q Description of boilers and industrial furnaces burning hazardous waste,
 including type and capacity of device;

       (D) A scaled plot plan showing the entire facility and location of the boilers and
 industrial furnaces burning hazardous waste; and

       (E) A description of the air pollution control system on each device burning
 hazardous waste, including the temperature of the flue gas at the inlet to the paniculate
 matter control system.
                                        20

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       (ii) Except for facilities complying with the Her I feed rate screening limits for
 metals or total chlorine and chloride provided by 266.106(b) or (e) and 266.107(b)(l) or
 (e) respectively, die estimated uncontrolled (at the inlet to the air pollution control system)
 emissions of paniculate matter, each metal controlled by 266.106, and hydrogen chloride
 and chlorine, and the following information to support such determinations:

       (A) The feed rate Qb/hr) of ash, chlorine, antimony,  arsenic, barium, beryllium,
 cadmium, chromium, lead, mercury, silver, thallium in each feedstream (hazardous waste,
 other fuels, industrial furnace feedstocks);

       (B) The estimated partitioning factor to the combustion gas for the materials
 identified in paragraph (b)(ii)(A) of this section and the basis for the estimate and an
 estimate of the partitioning to HC1 and Cl2 of total chloride and chlorine in feed materials.
 To estimate the partitioning factor, the owner or operator must use either best engineering
 judgment or the procedures specified in Methods Manual for Compliance with the BIF
 Regulations (incorporated by reference, see 260.11).

       (C) For industrial furnaces that recycle collected paniculate matter (PM) back into
 the furnace, the estimated enrichment factor for each metal. To estimate the enrichment
 factor, the owner or operator must use either best engineering judgment or the procedures
 specified in "Alternative Methodology for Implementing Metals Controls" in Methods
 MaflpqJ for Compliance with the BIF Regulations (incorporated by reference in 266.11).

       (D) If best engineering judgment is  used to estimate partitioning factors or
 enrichment factors under paragraphs (b)(ii)(B) or (b)(ii)(Q respectively, the basis for the
judgment.  When best engineering judgment is used to develop or evaluate data or
 information and make determinations under this section, the determinations must be made
 by a qualified, registered professional engineer and a certification of his/her determinations
 in accordance with 270.11 (d) of this chapter must be provided in the certification of
 precompliance.

       (iii) For facilities complying with the Tier I feed rate screening limits for metals or
 total chlorine and chloride provided by 266.106(b) or (c) and 266.107(b)(l) or (e), the
feed rate 0b/hr) of total chloride and chlorine, antimony, arsenic, barium, beryllium,
cadmium, chromium, lead, mercury, silver, and thallium in each feedstream (hazardous
waste, other fuels, industrial furnace feedstocks).

       (iv) For facilities complying with the Tier n or Her in emission limits for metals or
HC1 and Cfe (under 266.106(c) or (d) or 266.107(b)(2) or (c)), the estimated controlled
(outlet of the air pollution control system) emissions rates of paniculate matter, each metal
controlled by 266.106, and Hd and Cl2, and the following information to support such
determinations:

       (A) The estimated air pollution control system (APCS) removal efficiency for
paniculate matter, HO, Cl2 antimony, arsenic, barium, beryllium, cpHmfoin, chromium,
lead, mercury, silver, and thallium.

       (B) To estimate APCS removal efficiency, the owner or operator must use either
best engineering judgment or the procedures prescribed in Methods Manual for Compliance
with the BIF Regulations (incorporated by reference, see 260.11).
                                      21

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       (Q If best engineering judgment is used to estimate APCS removal efficiency, the
basis for die judgment Use of best engineering judgment must be in confonnance with
provisions of paragraph (b)(2XiiXD) of this section.

       (v) Determination of allowable emissions rates for HC1, Q2, antimony, arsenic,
barium, beryllium, cadmium, chromium, lead, mercury, silver, and thallium, and the
following information to support such determinations:
       (A)Forallfacilitit

       (7) Physical stack height;

       (2) Good engineering practice stack height as defined by 40 CFR 5 U00(u);

       (3) Maximum flue p** flow rate;

       (4) Maximum flue gas temperature;
       (5) Attach a
facility location and surrounding land within 5 km of the facility.

       (6) Identify terrain type: complex or noncomplex; and

       (7) Identify land use: urban or rural.;

       (B) For owners and operators using Tier in site specific dispersion modeling to
determine allowable levels under 266.106(d) or 266.1 07 (c), or adjusted Tier I feed rate
screening limits under 266.106(e) or 266.107(e):

       (1) Dispersion model and version used;
  Si

       (2) Source of meteorological data;

       (3) The dilution factor in micrograms per cubic meter per gram per second of
emissions for the maTi^n^ annual average off-site (unless on-site is required) ground level
concentration (MEI location); and

       (4) Indicate the MEI location on the map required under paragraph (bX2)(v)(A)(5);

       (vi) For facilities complying with the Tier n or m emissions rate controls for metals
or Hd and Q2, a comparison of the estimated controlled emissions rates determined under
paragraph (b)(2)(iv) with the allowable emission rates determined  under paragraph
       (vii) For facilities complying with the Tier I (or adjusted Tier I) feed rate screening
limits for metals or total chloride and chlorine, a comparison of actual feed rates of each
metal and total chlorine and chloride determined under paragraph (b)(2)(iii) to the Tier I
allowable feed rates; and

       (viii) For industrial furnaces mat feed hazardous waste for any purpose other dun
solely as an ingredient (as defined by paragraph (aX5)(u) of this section) at any location
                                       22

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 other than the product discharge end of the device, documentation of compliance with the
 requirements of paragraphs (a)(5Xi)(A), (B), and (C) of this section.

       (ix) For industrial furnaces that recycle collected paniculate matter (PM) back into
 the furnace and that will certify compliance with the metals emissions standards under
 paragraph (c)(3)(ii)(A) of this section:

       (A) The applicable paniculate matter standard in Ib/hr, and

       (B) The precompliance limit on the concentration of each metal in collected PM

       (3) Limits on operating conditions. The owner and operator shall establish limits
 on the following parameters consistent with the determinations made under paragraph
 (b)(2) of this section and certify (under provisions of paragraph (b)(9) of this section) to
 the Director that the facility will operate within the limits during interim status when there is
 hazardous waste in the unit until revised certification of precompliance under paragraph
 (b)(8) of this section or certification of compliance under paragraph (c) of this section:

       (i) Feed rate of total hazardous waste and (unless complying with the Tier 1 or
 adjusted Tier I metals feed rate screening  limits under 266.106(b) or (e)) pumpable
 hazardous waste;

       (ii) Feed rate of each metal in die following feed streams:

       (A) Total feed streams, except  that industrial furnaces that must comply with the
 alternative metals implementation approach under paragraph (b)(4) of this section must
 specify limits on the concentration of each metal in collected paniculate matter in lieu of
 feed rate limits for total feedstreams;

       (B) Total hazardous waste feed;  and

       (C) Total pumpable hazardous waste feed, unless complying with the Tier I or
 adjusted Tier I metals feed rate screening limits under 266.106(b) or (e);

       (iii) Total feed rate of chlorine and chloride in total feed streams;

       (iv) Total feed rate of ash in total feed streams, except that the ash feed rate for
cement kilns and light-weight aggregate kilns is not limited; and

       (v) Maximum production rate of the device in appropriate units when producing
normal product.

       (4) Operating requirements for furnaces that recycle PM. Owners and operators of
furnaces that recycle collected paniculate matter (PM) back into the furnace and that will
certify compliance with the metals emissions controls under paragraph (c)(3)(ii)(A) of this
section must comply with the special operating requirements provided  in "Alternative
Methodology for Implementing Metals Controls " in Methods Manual for Compliance with
the BIF Regulations (incorporated by reference in 260.11).

       (5) Measurement of feed rates and production rate, (i) General requirements.
Limits on each of the parameters specified in paragraph (b)(3) of this section (except for
limits on metals concentrations in collected paniculate matter (PM) for industrial furnaces
that recycle collected PM) shall be established and continuously monitored under either of
the following methods:


                                       23

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       (A) Instantaneous limits.  A limit for a parameter may be established and
continuously monitored on an instantaneous basis (i.e., the value that occurs at any time)
not to be exceeded at any time; or

       (B) Hourly rotting average limits. A limit for a parameter may be established and
continuously monitored on an hourly rolling average basis defined as follows:

       (/) A continuous monitor is one which continuously samples the regulated
parameter without interruption, and evaluates the detector response at least once each IS
seconds, and computes and records the average value at least every 60 seconds.

       (2) An hourly rolling average is the arithmetic mean of the 60 most recent 1-minute
average values recorded by the continuous monitoring system.

       (n) Rolling average limits for carcinogenic metals and lead. Feed rate limits for the
carcinogenic metals (arsenic, beryllium, cadmium, and chromium)  and lead may be
established either on an hourly rolling average basis as prescribed by paragraph (e)(5)(i)(B)
or on (up to) a 24 hour rolling average basis.  If the owner or operator elects to use an
averaging period from 2 to 24 hours:

       (A) The feed rate of each metal shall be limited at any time to ten times the feed rate
that would be allowed on a hourly rolling average basis;

       (B) The continuous monitor shall meet the following specifications:

       (!) A continuous monitor is one which continuously samples the regulated
parameter without interruption, and evaluates the detector response at least once each IS
seconds, and computes and records the average value at least every 60 seconds.

       (2) The rolling average for the selected averaging period is defined as the arithmetic
mean of the most recent one hour block averages for the averaging period.  A one hour
block average is the arithmetic mean of the one minute averages recorded during the 60-
minute period beginning at one minute after the beginning of preceding clock hour.

       (iii) Feed rate limits for metals, total chloride and chlorine, and ash. Feed rate limits
for metals, total chlorine and chloride, and ash are established and monitored by knowing
the concentration of the substance (i.e., metals, chloride/chlorine,  and ash) in each
feedstream and the flow rate of the feedstream.  To monitor the feed rate of these
substances, the flow rate of each feedstream must  be monitored under the continuous
monitoring requirements of paragraphs (b)(5)(0 and (ii) of this section.

       (6) Public notice requirements at precompliance. On or before [the effective date of
mis rule] the owner or operator must submit a notice with the following information for
publication in a major local newspaper of general circulation and send a copy of the notice
to the appropriate units of State and local government The owner and operator must
provide to the Director with the certification of precompliance evidence of submitting the
notice  for publication .  The notice, which shall be entitled "Notice of Certification of
Precompliance with Hazardous Waste Burning Requirements of 40 CFR 266.103(b)n,
must include:

       (i) Name and address of the owner and operator of the facility as well as the
location of me device burning hazardous waste;
                                      24

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       (ii) Date that the certification of precompliance is submitted to the Director,

       (iii) Brief description of the regulatory process required to comply with the interim
 status requirements of this section including required emissions testing to demonstrate
 conformance with emissions standards for organic compounds, paniculate matter, metals,
 and HC1 and Cfc;

       (iv) Types and quantities of hazardous waste burned including, but not limited to,
 source, whether solids or liquids, as well as an appropriate description of the waste;

       (v) Type of device(s) in which the hazardous waste is burned including a physical
 description and mannum production rate of each device;
unit;
       (vi) Types and quantities of other fuels and industrial furnace feedstocks fed to each
       (vii) Brief description of the basis for this certification of precompUance as specified
in paragraph (b)(2) of this section;

       (viii) Locations where the operating record for the facility can be viewed and copied
by interested parties.  These locations shall at a minimum include:

       (A) The Agency office where the supporting documentation was submitted or
another location designated by the Director, and

       (B) The facility site where the device is located;

       (ix) Notification of die establishment of a facility mailing list whereby interested
parties shall notify the Agency that they wish to be placed on the mailing list to receive
future information and notices about this facility, and

       (x) Location (mailing address) of the applicable EPA Regional Office, Hazardous
Waste Division, where further information can be obtaii
waste burning.
! obtained on EPA regulation of hazardous
       (7) Monitoring other operating parameters. When tile monitoring systems for the
operating parameters listed in paragraphs (c)(l)(v through xiii) of this section are installed
and operating in conformance with vendor specifications or (for CO, HC, and oxygen)
specifications provided by the Methods Manual for Compliance with the BIF Regulations
(incorporated by reference, see 260.11), as appropriate, the parameters shall be
continuously monitored and records shall be maintained in the operating record.

       (8) Revised certification of precompliance. The owner or operator may revise at
any time the information and operating conditions documented under paragraphs (b)(2) and
(b)(3) of this section  in the certification of precompliance by submitting a revised
certification of precompliance under procedures provided by those paragraphs.

       0) The public notice requirements of paragraph 0>X6) of this section do not apply to
recertifications.

       (ii) The owner and operator must operate the faculty within the limits established for
the operating parameters under paragraph (b)(3) of this section until a revised certification
                                       25

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is submitted under this paragraph or a certification of compliance is submitted under
paragraph (c) of mis section.

       (9) Certification of precompliance statement. The owner or operator must include
the following signed statement with the certification of precompliance submitted to the
Director:

       " I certify under penalty of law that this information was prepared under my
direction or supervision in accordance with a system designed to ensure that qualified
personnel properly gathered and evaluated the information and supporting documentation.
Copies of all emissions tests, dispersion modeling results and other information used to
determine conformance with the requirements of 266.103(b) are available at the facility
and can be obtained from the facility contact person listed above. Based on my inquiry of
the person or persons who manages the facility, or those persons directly responsible for
gathering the information, the information submitted is, to the best of my knowledge and
belief, true, accurate, and complete. I am aware that there are significant penalties for
submitting false information, including the possibility of fine and imprisonment  for
knowing violations.

       I also acknowledge that the operating limits established in this certification pursuant
to 266.103(b)(3) and (4) are enforceable limits at which the facility can legally operate
during interim status until: (1) a revised certification of precompliance is submitted, (2) a
certification of compliance is submitted, or (3) an operating permit is issued."

       (c) Certification of compliance. On or before [date 18 months after promulgation of
the rule], the owner or operator shall conduct emissions testing to document compliance
with the emissions standards of 266.104(b) through (e), 266.105, 266.106,  266.107,
and paragraph  (a)(5)(i)(D) of this section, under the procedures prescribed by mis
paragraph, except under extensions of time provided by paragraph (c)(7). Based on the
compliance test, the owner or operator shall submit to the Director a complete and accurate
 "certification of compliance" (under paragraph (c)(4) of this section) with those emission
 standards establishing limits on the operating parameters specified in paragraph (c)(l).

       (1) Limits on operating conditions. The owner or operator shall establish limits on
 the following parameters based on operations during the compliance test (under procedures
 prescribed in paragraph (c)(4)(iv) of this section) and include these  limits with the
 certification of compliance. The boiler or industrial furnace must be operated in accordance
 with these operating limits at all times when there is hazardous waste in the unit until an
 operating permit is issued.

       (i) Feed rate of total hazardous waste and (unless complying with the Tier I or
 adjusted Tier I metals feed rate screening limits under 266.106(b) or (e)), pumpable
 hazardous waste;

       0i) Feed rate of each metal in die following feedstreams:

       (A) Total feedstreams, except that industrial furnaces that must comply with the
 alternative metals implementation approach under paragraph (c)(3)(ii) of this section must
 specify limits on the concentration of each metal in collected paniculate matter in lieu of
 feed rate limits for total feedstreams;

        (B) Total hazardous waste feed (unless complying with the Tier I or adjusted Tier I
 metals feed rate screening limits under 266.106(b) or (e)); and
                                       26

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       (Q Total pumpable hazardous waste feed;

       (iii) Total feed rate of chlorine and chloride in total feed streams;

       (iv) Total feed rate of ash in total feed streams, except that the ash feed rate for
cement kilns and light-weight aggregate kilns is not limited;

       (v) Carbon  monoxide concentration,  and  where required,  hydrocarbon
concentration in stack gas. When complying with the CO controls of 266.104(b), the CO
limit is 100 ppmv, and when complying with the HC controls of 266.104(c), the HC limit
is 20 ppmv.  When  complying with the CO controls  of 266.104(c), the CO limit is
established based on the compliance test;

       (vi) Maximum production rate of the device in appropriate units when producing
normal product;

       (vii) Maximum combustion chamber temperature where the temperature
measurement is as close to the combustion zone as possible and is upstream of any quench
water injection, except for boilers and industrial furnaces  that have only pumpable liquid or
gaseous feed streams (unless complying with the Tier I or adjusted Tier I metals feed rate
screening limits under 266.106(b) or (e));

       (viii) Maximum flue gas temperature entering a  paniculate matter control device
(unless complying with Tier I or adjusted Tier I metals feed rate screening limits  under
266.106(b) or (e));

       (ix) For systems using wet scrubbers, including wet ionizing scrubbers (unless
complying with the  Tier I or adjusted Tier I metals feed  rate screening limits  under
266.106(b) or (e) and the total chlorine and chloride  feed rate screening limits  under
266.107(b)(l)or(e)):

       (A) Minimum liquid to  flue gas ratio;

       (B) Minimum scrubber blowdown from the system or maximum suspended  solids
content of the scrubber water, and

       (Q Minimum pH level of the scrubber water,

       (x) For systems using venturi scrubbers, the minimum differential gas pressure
across the venturi (unless complying with the Tier I or adjusted Tier I metals feed rate
screening limits under 266.106(b) or (e) and the total chlorine and chloride feed rate
screening limits under 266.107(b)(l) or (e));

       (xi) For systems using  dry scrubbers (unless complying with the Tier I or adjusted
Tier I metals feed rate screening limits under 266.106(b) or  (e) and the total chlorine and
chloride feed rate screening limits under 266.107(b)(l) or (e)):

       (A) Minimum caustic feed rate* and

       (B) Maximum flue gas flow rate;

       (xii) For systems using wet ionizing scrubbers or electrostatic precipitators (unless
complying with the  Tier I or adjusted Tier I metals feed  rate screening limits  under
                                       27

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266.106(b) or (e) and the total chlorine and chloride feed rate screening limits under
266.107(b)(l)or(e)):

       (A) Minimum electrical power in Itilovok amperes (kVA) to the prccipitator plates;
and
       (B) Maximum flue gas flow rate;
       (xiii) For systems using fabric filters (baghouses), the minimum pressure drop
(unless complying with the Tier I or adjusted Tier I metals feed rate screening limits under
266.106(b) or (e) and the total chlorine and chloride feed rate screening limits under
266.107(b)(l) or (e)).

       (2) Prior notice of compliance testing. At least 30 days prior to the compliance
testing required by paragraph (c)(3) of this section, the owner or operator shall notify the
Director and submit the following information:
       (i) General facility information including:

       (A) EPA facility ID number,

       (B) Facility name, contact person, telephone number, and address;

       (Q Person responsible for conducting compliance test, including company name,
address, and telephone number, and a statement of qualifications;

       (D) Planned date of the compliance test;

       (ii) Specific information on each device to be tested including:

       (A) Description of boiler or industrial furnace;

       (B) A scaled plot plan showing the entire facility and location of the boiler or
industrial furnace;

       (Q A description of the air pollution control system;

       (D) Identification of the continuous emission monitors that are Installed', including:

       (7) Carbon monoxide monitor,

       (2) Oxygen monitor,

       (5) Hydrocarbon monitor, specifying the ininimmn temperature of the system and,
if the temperature is less than ISCrC, an explanation of why a heated system is not used
(see paragraph (cX5) of this section) and a brief description of the sample gas conditioning
system;

        (E) Indication of whether the stack is shared with another device that will be in
operation during the compliance test;

       (F) Other information useful to an understanding of the system design or operation.

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       (iii) Information on the testing planned, including a complete copy of the test
 protocol and Quality Assurance/Quality Control (QA/QC) plan, and a summary description
 for each test providing the following information at a
       (A) Purpose of the test (e.g., demonstrate compliance with emissions of paniculate
 matter); and

       (B) Planned operating conditions, including levels for each pertinent parameter
 specified in paragraph (c)(l) of this section.

       (3) Compliance testing,  (i) General. Compliance testing must be conducted under
 conditions for which the owner or operator has submitted a certification of precompliance
 under paragraph (b) of this section and under conditions established in the notification of
 compliance testing required by paragraph (c)(2) of this section.

       (ii) Special requirements for industrial furnaces that recycle collected PM. Owners
 and operators of industrial furnaces that recycle back into the furnace paniculate matter
 (PM) from the air pollution control system must comply with one of the following
 procedures for testing to determine compliance with the metals standards of 266.106(c) or
 (d):

       (A) The special testing requirements prescribed in "Alternative Method for
 Implementing Metals Controls" in Methods Manual for Compliance with the BIF
 Regulations (incorporated by reference in 260. 1 1 ); or

       (B) Stack emissions testing for a minimum of 6 hours each day while hazardous
 waste is burned during interim status.  The testing must be conducted when burning normal
 hazardous waste for that day at normal feed rates for that day and when the air pollution
 control system is  operated under normal conditions. During interim status, hazardous
 waste analysis for metals content must be sufficient for the owner or operator to determine
 if changes in metals content may affect the ability of the facility to meet the metals
 emissions standards established under 266.106(c) or (d). Under this option, operating
 limits (under paragraph (c)(l)) must be established during compliance testing under
 paragraph (c)(3) only on the following parameters:
       (/) Feed rate of total hazardous waste;

       (2) Total feed rate of chlorine and chloride in total feed streams;

       (3) Total feed rate of ash in total feed streams, except that the ash feed rate for
cement kilns and light-weight aggregate kilns is not limited;

       (4)  Carbon monoxide concentration,  and  where required, hydrocarbon
concentration in stack gas;

       (5) Maximum production rate of the device in appropriate units when producing
normal product; or

       (C) Conduct compliance testing to determine compliance with the metals standards
to establish limits on the operating parameters of paragraph (c)(l) only after the kiln system
has been conditioned to enable it to reach equilibrium with respect to metals fed into the
system and metals emissions. During conditioning, hazardous waste and raw materials
                                      29

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having the same metals content as will be fed during the compliance test must be fed at the
feed rates that will be fed during the compliance test

      (iii) Conduct of compliance testing. (A) If compliance with all applicable emissions
standards of 266.104 through 266.107 is not demonstrated simultaneously during a set
of test runs, the operating conditions of additional test runs required to demonstrate
compliance with remaining emissions standards must be as close as possible to the original
operating conditions.

      (B) Prior to obtaining test data for purposes of demonstrating compliance with the
applicable emissions standards of 266.104 through 266.107 or establishing limits on
operating parameters under this section, the facility must operate under compliance test
conditions for a sufficient period to reach steady-state operations. Industrial furnaces that
recycle collected paniculate matter back into the furnace and that comply with paragraphs
(c)(3)(ii)(A) or (B) or this section, however, need not reach steady state conditions with
respect to the flow of metals in the system prior to beginning compliance testing for metals.

      (Q Compliance test data on the level of an operating parameter for which a limit
must be established in the certification of compliance must be obtained during emissions
sampling for the poUutant(s) (i.e., metals, PM, HC1/C12. organic compounds) for which
the parameter must be established as specified by paragraph (c)(l) of this section.

      (4) Certification of compliance. Wi
the owner or operator must certify to the Director
of 266.1
                                                iliance with die emissions \
            ..), (c), and (e), 266.105,266.106,266".107, and paragraph (a)(5)(i)(D) of
this section. TTie certification of compliance must include the following information:

       (i) General facility and testing information including:

       (A) EPA facility ID number,

       (B) Facility name, contact person, telephone number, and address;

       (Q Person responsible for conducting compliance test, including company name,
address, and telephone number, and a statement of qualifications;
       (D) Date(s) of each compliance'

       (E) Description of boiler or industrial furnace tested;

       (F) Person responsible for quality assurance/quality control (QA/QC), title, and
telephone number, and statement that procedures prescribed in the QA/QC plan submitted
under 266.103(c)(2)(iii) have been followed, or a description of any changes and an
explanation of why changes were necessary.

       (G) Description of any changes in the unit configuration prior to or during testing
that would alter any of the information submitted in the prior notice of compliance testing
under paragraph (c)(2) of mis section, and an explanation of why the changes were
necessary;

       (H) Description of any changes in the planned test conditions prior to or during the
testing that alter any of die information submitted in the prior notice of compliance testing
                                       30

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under paragraph (c)(2) of this section, and an explanation of why the changes were
necessary; and

       (D The complete report on results of emissions testing.

       (ii) Specific information on each test including:

       (A) Purpose(s) of test (e.g., demonstrate conformance with the emissions limits for
paniculate matter, metals, HC1, Cl2, and CO)

       (B) Summary of test results for each run and for each test including the following
information:

       (/) Date of run;

       (2) Duration of run;

       (3) Time-weighted average and highest hourly rolling average CO level for each run
and for the test;

       (4) Highest hourly rolling average HC level, if HC monitoring is required for each
run and for the test;

       (5)  If dioxin and furan testing is required under 266.104(e), time-weighted
average emissions for each run and for the test of chlorinated dioxin and furan emissions,
and the predicted maximum annual average ground level concentration of the toxicity
equivalency factor;

       (6) Time-weighted average paniculate matter emissions for each run and for the test;

       (7) Time-weighted average HC1 and C\2 emissions for each run and for the test;

       (8) Time-weighted average emissions of the metals subject to regulation under
266.107 for each run and for the test; and

       (9) QA/QC results.

       (iii) Comparison of the actual emissions during each test with the emissions limits
prescribed by 266.104(b), (c), and (e), 266.105,266.106, and 266.107 and established
for the facility in the certification of precompliance under paragraph (b) of this section.

       (iv) Determination of operating limits based on all valid runs of die compliance test
for each applicable parameter listed in paragraph (c)(l) of  this section using either of the
following procedures:

       (A) Instantaneous limits. A parameter may be measured and recorded on an
instantaneous basis (Le., the value that occurs at any time) and the operating limit specified
as the time-weighted average during all runs of the compliance test; or

       (B) Hourly rolling average basis. (1) The limit for a parameter may be established
and continuously monitored on an hourly rolling average basis defined as follows:
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       (0 A continuous monitor is one which continuously samples the regulated
parameter without interruption, and evaluates the detector response at least once each IS
seconds, and computes and records the average value at least every 60 seconds.

       (i'i) An hourly rolling average is the arithmetic mean of the 60 most recent 1-minute
average values recorded by the continuous monitoring system.

       (2) The operating limit for the parameter shall be established based on compliance
test data as the average over all test runs of the highest hourly rolling average value for each
run.

       (O Rolling average limits for carcinogenic metals and lead. Feed rate limits for the
carcinogenic metals (i.e., arsenic, beryllium, cadmium and chromium) and lead may be
established  either on an hourly rolling average basis as prescribed by  paragraph
(c)(4)(iv)(B) of this section or on (up to) a 24 hour rolling average basis. If the owner or
operator elects to use an averaging period of from 2 to 24 hours:

       (!) The feed rate of each metal shall be limited at any time to ten times the feed rate
that would be allowed on a hourly rolling average basis;

       (2) The continuous monitor shall meet the following specifications:

       (I) A continuous monitor is one which continuously samples the regulated
parameter without interruption, and evaluates the detector response at least once each IS
seconds, and computes and records the average value at least every 60 seconds.
       (it) The rolling average for the selected averaging period is defined as the arithmetic
mean of the most recent one hour block averages for the averaging period.  A one hour
block average is the arithmetic mean of the one minute averages recorded during the 60-
minute period beginning at one minute after the beginning of preceding clock hour; and

       (3) The operating limit for the feed rate of each metal shall be established based on
compliance test data as the average over all test runs of the highest hourly rolling average
feed rate for each run.

       (D) Feed rate limits for metals, total chloride and chlorine, and ash. Feed rate limits
for metals, total chlorine and chloride, and ash are established and monitored by knowing
the concentration of the substance (i.e., metals, chloride/chlorine, and ash) in each
feedstream and the flow rate of the feedstream.  To monitor the feed rate of these
substances, the flow rate of each feedstream must be monitored under the continuous
monitoring requirements of paragraphs (cX4XivXA) through (Q of this section.

       (v) Certification of compliance statement. The following statement shall accompany
die certification of compliance:

       "I certify under penalty of law that this information was prepared under my
direction or supervision in accordance with a system designed to ensure that qualified
personnel properly gathered and evaluated the information and supporting documentation.
Copies of all emissions tests, dispersion modeling results and other information used to
determine confonnance with the requirements of 266.103(c) are available at the facility
and can be obtained from the facility contact person listed above. Based on my inquiry of
the person or persons who manages the facility, or those persons directly responsible for
gathering the information, the information submitted is, to the best of my knowledge and
                                        32

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 belief, true, accurate, and complete.  I am aware that there are significant penalties for
 submitting false information, including the possibility of fine and imprisonment for
 knowing violations.

       I also acknowledge that the operating conditions established in this certification
 pursuant to 266.103(c)(4)(iv) are enforceable limits at which the facility can legally
 operate during interim status until a revised certification of compliance is submitted."

       (5) Special requirement for HC monitoring systems. When an owner or operator
 is required to comply with the hydrocarbon  (HC) controls provided by 266.104(c) or
 paragraph (a)(5)(i)(D) of this section, a conditioned gas monitoring system may be used in
 confonnance with specifications provided in Method,*} MflflUftl for Compliance with the BIF
 Regulations (incorporated by reference, see 260.11) provided that the owner or operator
 submits a certification of compliance without using extensions of time provided by
 paragraph (c)(7) of this section.

       (6) Special operating requirements for  industrial furnaces that recycle collected PM.
 Owners and operators of industrial furnaces that recycle back into the furnace paniculate
 matter (PM) from the air pollution control system must*

       (i) When complying with the requirements of paragraph (c)(3)(ii)(A) of this section,
 the operating requirements prescribed in "Alternative Method to Implement the Metals
 Controls" in Methods Manual for Compliance with the BIF Regulations (incorporated by
 reference in 260.11); and

       (ii)  When complying with the requirements of paragraph (c)(3)(ii)(B) of this
 section, the operating requirements prescribed by that paragraph.

       (7) Extensions of time,  (i) If the owner or operator does not submit a complete
 certification of compliance for all of the applicable  emissions standards of 266.104,
 266.105, 266.106, and 266.107 by [insert date 18 months from promulgation], he/she
 must either
       (A) Stop burning hazardous waste and beu
of this section for the hazardous waste portion of the facility; or
       (B) Limit hazardous waste burning to a total period of 720 hours for the period of
time beginning [insert date 18 months from promulgation], submit a notification to the
Director by [insert date 18 months from promulgation] stating that the facility is operating
under restricted interim status and intends to resume burning hazardous waste, and submit
a complete certification of compliance by [insert date 30 months from promulgation]; or
section.
       (C) Obtain a case-by-case extension of time under paragraph (c)(7)(ii) of this
       (ii) The owner or operator may request a case-by-case extension of time to extend
any time limit provided by paragraph (c) of this section if compliance with the time limit is
not practicable for reasons beyond the control of the owner or operator.

       (A) In granting an extension, the Director may apply conditions as the facts warrant
to ensure timely compliance with the requirements of this section and that the facility
operates in a manner that does not pose a hazard to human health and me environment;
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       (B) When an owner and operator request an extension of time to enable them to
obtain a RCRA operating permit because the facility cannot meet the HC limit of
266.104(f) of this chapter.

       (/) The Director shall, in considering whether to grant the extension:

       (i) Determine whether the owner and operator have submitted in a timely manner a
complete Part B permit application that includes information required under 270.22(b) of
this chapter, and

       (ii) Consider whether the owner and operator have made a good faith effort to
certify compliance with all other emission controls, including the controls on dioxins and
furans of 266.104(e) and the controls on PM, metals, and HC1/C12-

       (2) If an extension is granted, the Director shall, as a condition of the extension,
require the facility to operate under flue gas concentration limits on CO and HC that, based
on available information, including information in the Pan B permit application, are
baseline CO and HC levels as defined by 266.104(0(1).

       (8) Revised certification of compliance.  The owner or operator may submit at any
time a revised certification of compliance (recertification of compliance) under the following
procedures:

       (i) Prior to submittal of a revised certification of compliance, hazardous waste may
not be burned for more than a total of 720 hours under operating conditions that exceed
those established under a current certification of compliance, and such burning may be
conducted only for purposes of determining whether the facility can operate under revised
conditions and continue to meet the applicable emissions standards of 266.104,
266.105,266.106, and 266.107;

       (ii) At least 30 days prior to  first burning hazardous waste under operating
 conditions that exceed those established under a current certification of compliance, the
owner or operator shall notify the Director and submit the following information:

       (A) EPA facility ID number, and facility name, contact person, telephone number,
and address;

       (B) Operating conditions that  the owner or operator is seeking to revise and
description of the changes in facility design or operation that prompted the need to seek to
revise the operating conditions;

       (C) A determination mat when operating under the revised operating conditions, the
applicable emissions standards of 266.104, 266.105, 266.106, and 266.107 are not
likely to be exceeded. To document this determination, the owner or operator shall submit
the applicable information required under paragraph (bX2) of this section; and

        (D)  Complete emissions testing protocol for any pretesting and for a new
compliance test to determine compliance with the applicable emissions standards of
266.104, 266.105, 266.106,  and 266.107 when operating under revised operating
conditions.  The protocol shall include a schedule of pre-testing and compliance testing. If
 the owner and operator revises the scheduled date for the compliance test, he/she shall
 notify the Director in writing at least 30 days prior to the revised date of die compliance test;
                                       34

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       (iii) Conduct a compliance test under the revised operating conditions and the
protocol submitted to the Director to determine compliance with the applicable emissions
standards of 266.104,266.105,266.106, and 266.107; and

       (iv) Submit a revised certification of compliance under paragraph (c)(4) of this
section.

       (d) Periodic Recertifications.  The owner or operator must conduct compliance
testing and submit to die Director a recertification of compliance under provisions of
paragraph (c) of this section within three years from submitting the previous certification or
recertification. If the owner or operator seeks to recertify compliance under new operating
conditions, he/she must comply with the requirements of paragraph (c)(8) of this section.

       (e) Noncompliance with certification schedule. If the owner or operator does not
comply with the interim status compliance schedule provided by paragraphs (b), (c), and
(d) of this section, hazardous waste burning must terminate on the date that the deadline is
missed, closure activities must begin under paragraph (1) of this section, and hazardous
waste burning may not resume except under an operating permit issued under 270.66 of
this chapter.

       (f) Start-up  and shut-down.  Hazardous waste (except waste fed solely as an
ingredient under the Tier I (or adjusted  Tier I) feed rate  limits for metals and
chloride/chlorine) must not be fed into the device during start-up and shut-down of the
boiler or industrial furnace, unless the device is operating within the conditions of operation
specified in the certification of compliance.

       (g) Automatic waste feed cutoff. During the compliance test required by paragraph
(c)(3) of this section, and upon certification of compliance under paragraph (c) of this
section, a boiler  or  industrial furnace must be operated with a functioning system that
automatically cuts off the hazardous waste feed when the applicable operating conditions
specified in paragraphs (c)(l)(i) and (v through xtii) of this section deviate from those
estabUshed in the  certification of compUance. In addition:

       (1) To minimize emissions or organic compounds, the minimum combustion
chamber temperature (or the indicator of combustion chamber temperature) that occurred
during the compliance test must be maintained while hazardous waste or hazardous waste
residues remain in the combustion chamber, with the minimum temperature during the
compliance test defined as either

       (i) If compliance with the combustion chamber temperature limit is based on a
hourly rolling average, the minimum temperature during the compliance test is considered
to be the average over all runs of the lowest hourly tolling average for each run; or

       (ii) If compUance with the combustion chamber temperature limit is based on an
instantaneous temperature measurement, the minimum temperature during the compliance
test is considered to be the time-weighted average temperature during all runs of the test;
and
                         ters limited by the certification of compliance must continue to
be monitored during the cutoff, and the hazardous waste feed shall not be restarted until the
levels of those parameters comply with the limits estabUshed in the certification of
compliance.
       (2) Operating par
     nitored during the
                                      35

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       00 Fugitive emissions. Fugitive emissions must be controlled by:

       (1) Keeping the combustion zone totally sealed against fugitive emissions; or

       (2) Maintaining the combustion zone pressure lower than atmospheric pressure; or

       (3) An alternate means of control that the owner or operator can demonstrate
provide fugitive emissions control equivalent to maintenance of combustion zone pressure
lower than atmospheric pressure.  Support for such demonstration shall be included in the
operating record.

       (i) Changes. A boiler or industrial furnace must cease burning hazardous waste
when changes in combustion properties, or feed rates of the hazardous waste, other fuels,
or industrial furnace feedstocks, or changes in the boiler or industrial furnace design or
operating conditions deviate from the limits specified in the certification of compliance.

       (j) Monitoring and Inspections. (1) The owner or operator must monitor and record
the following, at a nrininrom, while burning hazardous waste:

       (i) Feed rates and composition of hazardous  waste, other fuels, and industrial
furnace feed stocks, and feed rates  of ash, metals, and total chloride and chlorine as
necessary to ensure confonnance with the certification of precompliance or certification of
compliance;

       (ii)  Carbon monoxide (CO), oxygen, and if applicable, hydrocarbons (HC), on a
continuous basis at a common point in the boiler or industrial furnace downstream of the
combustion zone and prior to release of stack gases to the atmosphere in accordance with
the operating limits specified in the  certification of compliance. CO, HC, and oxygen
monitors must be installed, operated, and maintained in accordance with methods specified
in tytethods Manual for (Compliance with the BBF Regulations (incorporated by reference,
see  260.11).

       (iii) Upon the request of the Director, sampling and analysis of the hazardous waste
(and other fuels and industrial furnace feed stocks as appropriate) and the stack gas
emissions must be conducted to  verify that the operating conditions established in the
certification of precompliance or certification of compliance achieve the applicable standards
of |266.104, 266.105,266.106, and 266.107.

       (2) The boiler or industrial furnace and associated equipment (pumps, valves,
pipes, fuel storage tanks, etc.) must be subjected to thorough visual inspection when they
contain hazardous waste, at least daily for leaks, spills, fugitive emissions, and signs of
tampering.

       (3) The automatic hazardous waste feed cutoff system and associated alarms must
be tested at least once every 7 days when hazardous waste is burned to verify operability,
unless the owner or operator can demonstrate mat weekly inspections will unduly restrict or
upset operations and that less frequent inspections will be adequate. Support for such
demonstration shall be included in the operating record. At a minimum, operational testing
must be conducted at least once every 30 days.

        (4) These monitoring and inspection data must be recorded and the records must be
 placed in the operating log.
                                        36

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       (k) Recordkeeping. The owner or operator must keep in the operating record of the
 facility all information and data required by this section fora period of three years.
       (1) Closure. At closure, the owner or operator most remove all hazardous waste
and hazardous waste residues (including, but not limited to, ash, scrubber waters, and
scrubber sludges) from the boiler or industrial furnace and must comply with 265.1 1 1-
265.1 15 of this chapter.

(Approved by the Office of Management and Budget under control number _ )

  266.104 - Standards to control organic emissions.

       (a) ORE standard. (1) General.  Except as provided in paragraph (a)(3) of this
section, a boiler or industrial furnace burning hazardous waste must achieve a destruction
and removal efficiency (DRE) of 99.99% for all organic hazardous constituents in the
waste feed. To demonstrate confonnance with this requirement, 99.99% DRE must be
demonstrated during a trial bum for each principal organic hazardous constituent (POHC)
designated (under paragraph (a)(2) of this section) in its permit for each waste feed.  DRE
is determined for each POHC from the following equation:
DRE
=[
Wi
      ]
                             X  100
                       n
       where:
       W^ = Ma55 feed **** f one principal organic hazardous constituent (POHC) in the
hazardous waste fired to die boiler or industrial furnace; and

       Wout - Mass emission rate of the same POHC present in stack gas prior to release
to the atmosphere.

       (2) Designation of POHCs. Principal organic hazardous constituents (POHCs) are
those compounds for which compliance with the DRE requirements of this section shall be
demonstrated in a trial burn in confonnance with procedures prescribed in 270.66 of this
chapter. One or more POHCs shall be designated by the Director for each waste feed to be
burned. POHCs shall be designated based on the degree of difficulty of destruction of the
organic constituents in the waste and on their concentrations 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 Pan 261,
Appendix VDI of mis chapter mat are also present in the normal waste feed. However, if
the applicant demonstrates to the Regional Administrator's satisfaction mat a compound not
listed in Appendix Vm or not present in the normal waste feed is a suitable indicator of
compliance with the DRE requirements of this section, mat compound may be designated
as a POHC Such POHCs need not be toxic or organic compounds.

       (3) Dioxin-listed waste.  A boiler or industrial furnace burning hazardous waste
containing (or derived from) EPA Hazardous Wastes Nos. F020, F021, F022, F023,
F026, or F027 must achieve a destruction and removal efficiency (DRE) of 99.9999% for
each POHC designated  (under paragraph (a)(2) of this  section) in Us permit  This
performance must be demonstrated on POHCs that are more difficult to burn than tetra-,
penta-, and hexachlorodibenzo-p-dioxins and dibenzofurans. DRE is determined for each
                                     37

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POHC from the equation in paragraph (a) of this section.  In addition, the owner or
                          trial furnac
operator of die boiler or industrial
                                     must notif  the Director of intent to bum EPA
Hazardous Waste Nos.F020,F021,F022,F023,F026, or F027.

       (4) Automatic waiver ofDRE trial burn. Owners and operators of boilers operated
under the special operating requirements provided by  266.110 are considered to be in
compliance with the DRE standard of paragraph (aXl) of this section and are exempt from
the DRE trial burn.

       (S) Low risk waste. Owners and operators of boilers or industrial furnaces that
bum hazardous waste in compliance with the requirements of 266.109(a) are considered
to be in compliance with the DRE standard of paragraph (a)(l) of this section and are
exempt from the DRE trial burn.

       (b) Carbon monoxide standard. (1) Except as provided in paragraph (c) of this
section, the stack gas concentration of carbon monoxide (CO) from a boiler or industrial
furnace burning hazardous waste cannot exceed 100 ppmv on an hourly rolling average
basis (i.e., over any 60 minute period), continuously corrected to 7 percent oxygen, dry
gas basis.

       (2) CO and oxygen shall be continuously monitored  in confonnance with
"Performance Specifications for Continuous Emission Monitoring of Carbon Monoxide
and Oxygen in Hazardous Waste Incinerators, Boilers, and Industrial Furnaces" in
Methods Manual for Compliance with the BIF Regulations (incorporated by reference hi
260. 1 1 of this chapter).

       (3) Compliance with the 100 ppmv CO limit must be demonstrated during the trial
burn (for new facilities or an interim status facility applying for a permit) or the compliance
test (for interim status facilities). To demonstrate compliance, the highest hourly rolling
average CO level during any valid run of die trial burn or compliance test must not exceed
100 ppmv.

       (c) Alternative carbon monoxide standard.  (1) The stack gas concentration of
carbon monoxide (CO) from a boiler or industrial furnace burning hazardous waste may
exceed the 100 ppmv limit provided that stack gas concentrations of hydrocarbons (HC) do
not exceed 20 ppmv, except as provided  by paragraph (f) of this section for certain
industrial furnaces.

       (2) HC limits must be established under this section on an hourly rolling average
basis (i.e., over any 60 minute period), reported as propane, and continuously corrected to
7 percent oxygen, dry gas basis.

       (3) HC shall be continuously monitored in confonnance with "Measurement of
Total Hydrocarbons in Stack Gases from  Hazardous Waste Incinerators, Boilers, and
Industrial Furnaces" in Methods Manual  for Compliance with the BIF Regulations
(incorporated  by reference in 260.11 of this chapter).  CO and oxygen  shall be
continuously monitored in confonnance with paragraph (b)(2) of this section.

       (4) The alternative CO standard is established based on CO data during the trial
burn (for a new facility) and the compliance test (for an interim status facility). The
alternative CO standard is the average over all valid runs of the highest hourly average CO
level for each run. The CO limit is implemented on an hourly rolling average basis, and
continuously corrected to 7 percent oxygen, dry gas basis.
                                      38

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       (d) Special requirements for furnaces. Owners and operators of industrial furnaces
 (e.g., kilns, cupolas) that feed hazardous waste for a purpose other than solely as an
 ingredient (see 266.103(a)(5)(ii)) at any location other than the end where products are
 normally discharged and where fuels are normally fired must comply with the hydrocarbon
 limits provided by paragraphs (c) or (f) of this section irrespective of whether stack gas CO
 concentrations meet the 100 ppmv limit of paragraph (b) of this section.

       (e) Controls for dioxins andfurans. Owners and operators of boilers and industrial
 furnaces that are equipped with a dry paniculate matter control device that operates within
 the temperature range of 450-750F, and industrial furnaces operating under an alternative
 hydrocarbon limit established under paragraph (f) of this section must conduct a  site-
 specific risk assessment as follows to demonstrate that emissions of chlorinated dibenzo-p-
 dioxins and dibenzofurans do not result in an increased lifetime cancer  risk to the
 hypothetical pnaximinn exposed individual (MEI) exceeding 1 in 100,000:

       (1) During the trial burn (for new facilities or an interim status facility applying for a
 permit) or compliance test (for interim status facilities), determine emission rates of the
 tetra-octa congeners of chlorinated dibenzo-p-dioxins and dibenzofurans (CDDs/CDFs)
 using  Method  23, "Determination of  Polychlorinated  Dibenzo-p-Dioxins  and
 Polychlorinated Dibenzofurans (PCDFs) from Stationary Sources" in Methods Manual for
 Compliance with the B1F Regulations (incorporated by reference in 260.11).

       (2) Estimate the 2,3,7,8-TCDD toxicity equivalence of the tetra-octa CDDs/CDFs
 congeners using "Procedures for Estimating the Toxicity Equivalence of Chlorinated
 Dibenzo-p-Dioxin and Dibenzofuran Congeners" in Methods Manual for Compliance  with
 the BBF Regulations (incorporated by reference in 260.11). Multiply the emission rates of
 CDD/CDF congeners with a toxicity equivalence greater than zero (see the procedure) by
 die calculated toxicity equivalence factor to estimate the equivalent emission rate of 2,3,7,8-
 TCDD.

       (3) Conduct dispersion modeling using methods recommended in (guideline on Air
Quality Models, the "Hazardous Waste Combustion Air Quality Screening Procedure"
described in Methods  Manual for Compliance with the BIF Regulations, or "EPA
SCREEN Screening Procedure" as described in Screening Procedures for Estimating Air
Duality ^mpact of Stationary Sources (all three documents are incorporated by reference in
 260.11) to predict the maximum annual average off-site ground level  concentration of
2,3,7,8-TCDD equivalents  determined under paragraph (e)(2) of this section.  The
maximum annual average on-site concentration must be used when a person resides on-site;
and

       (4) The ratio of the predicted maximum annual average ground level concentration
of 2,3,7,8-TCDD equivalents to the risk-specific dose for 2,3,7,8-TCDD provided in
Appendix V of this part (2.2 X10"7) shall not exceed 1.0.

       (f) Alternative HC limit for furnaces with organic matter in raw material.  For
industrial  furnaces that cannot meet the 20 ppmv HC limit because of organic matter in
normal raw material, the Director may establish an alternative HC limit on a case-by-case
basis (under a Part B permit proceeding) at a level that ensures that flue gas HC (and CO)
concentrations when burning hazardous waste are not greater than when not bumii
the following requirements. However, cement kilns equipped with a by-pass duct meeting
                                       39

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the requirements of paragraph (g) of this section, are not eligible for an alternative HC
limit

       (1) The owner or operator must demonstrate that the facility is designed and
operated to minimize hydrocarbon emissions from fuels and raw materials when the
baseline HC (and CO) level is determined. The baseline HC (and CO) level is defined as
the average over all valid test runs of the highest hourly rolling average value for each run
when the facility does not burn hazardous waste, and produces normal products under
normal operating conditions feeding normal feedstocks and fuels. More than one baseline
level may be determined if the facility operates under different modes that may generate
significantly different HC (and CO) levels;

       (2) The owner or operator must develop an approach to monitor over time changes
in the operation of the facility that could reduce the baseline HC level;

       (3) The owner or operator must conduct emissions testing during the trial bum to:

       (i) Determine the baseline HC (and CO) level;

       (ii) Demonstrate that, when hazardous waste is burned, HC (and CO) levels do not
exceed the baseline level; and

       (iii) Identify die types and concentrations of organic compounds listed in Appendix
Vm, Part 261 of mis chapter, that are emitted and conducts dispersion modeling to predict
the ipaymuini annual average ground level concentration of each organic compound. On-
site ground level concentrations must be considered for this evaluation if a person resides
on site.

       (A) Sampling and analysis of organic emissions shall be conducted using
procedures prescribed by the Director.

       (B) Dispersion modeling shall be conducted according to procedures provided by
paragraph (e)(2) of this section; and
(tv) Demonstrate that
                                   annual average ground level concentrations of the
organic compounds identified in paragraph (f)(2)(iii) of this section do not exceed the
following levels:

       (A) For the noncarcinogenic compounds listed in Appendix IV of this part, the
levels established in Appendix IV;

       (B) For the carcinogenic compounds listed in Appendix V of mis part, the sum for
all compounds of the ratios of die actual ground level concentration to the level established
in Appendix V cannot exceed 1.0. To estimate the health risk from chlorinated dibenzo-p-
dioxins and dibenzofuran congeners, use the procedures prescribed by paragraph (e)(3) of
mis section to estimate the 23,7,8-TCDD toxicity equivalence of the congeners.
 meter.
       (C) For compounds not listed in Appendix IV or V, 0.09 micro-grams per cubic
       (4) All hydrocarbon levels specified under mis paragraph are to be monitored and
 reported as specified in paragraphs (cXl) and (cX2) of this section.
                                       40

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       (g) Monitoring CO and HC in the by-pass auci of a cement kiln. Cement kilns may
comply with the carbon monoxide and hydrocarbon limits provided by paragraphs (b), (c),
and (d) of this section by monitoring in the by-pass duct provided that:

       (1) Hazardous waste is fired only into the kiln and not at any location downstream
from the kiln exit relative to die direction of gas flow; and

       (2) The by-pass duct diverts a minimum of 10% of kiln off-gas into the duct(g)
Use of emissions test data to demonstrate conformance and establish operating limits:
Confonnance with the requirements of this section must be demonstrated simultaneously
by emissions testing or during separate runs under identical operating conditions. Further,
data to demonstrate compliance with the CO and HC limits provided by this section or to
establish alternative CO or HC limits provided by this section must be obtained during the
time that DRE testing, and where applicable, CDD/CDF testing is being conducted.

       (h) Use of emissions test data to demonstrate compliance and establish operating
limits. Compliance with the requirements  of  this section  must be demonstrated
simultaneously by emissions testing or during separate runs under identical operating
conditions. Further, data to demonstrate compliance with the CO and HC limits of this
section or to  establish alternative CO or HC limits under this section must be obtained
during the time that DRE testing, and where applicable, CDD/CDF testing under paragraph
(e) and comprehensive organic emissions testing under paragraph (0 is conducted.

       (i) Enforcement. For the purposes of permit enforcement, compliance with the
operating  requirements specified in the permit (under  266.102) will be regarded as
compliance with this section. However, evidence that compliance with those permit
conditions is insufficient to ensure compliance with the requirements of this section may be
"information" justifying modification or revocation and re-issuance of a permit under
270.41 of this chapter.

  266.105 Standards to control particulate matter.

       (a) A boiler or industrial furnace burning hazardous waste may not emit particulate
matter in excess of 180 milligrams per dry standard cubic meter (0.08 grains per dry
standard cubic foot) after correction to a stack gas concentration of 7% oxygen, using
procedures prescribed in 40 CFR Part 60, Appendix A, Methods 1 through 5, and Methods
Manual for Compliance with the BIF Regulations (incorporated by reference, see
260.11).

       (b) An owner or operator meeting the requirements of 266.109(b) for the low risk
waste exemption is exempt from the particulate matter standard.

       (c) For the purposes of permit enforcement, compliance with the operating
requirements specified in the permit (under  266.102) will be regarded as compliance with
mis section. However, evidence that compliance with those permit conditions is insufficient
to ensure compliance with the requirements of this section may be "information" justifying
modification or revocation and re-issuance of a permit under  270.41 of this chapter.

  266.106 Standards to control metals emissions.

       (a) General.  The owner or operator must comply with the metals standards
provided by paragraphs (b),  (c), (d), (e), or (f) of this section for each metal listed in
paragraph  (b) of this section that is present in the hazardous waste at detectable levels using
                                      41

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analytical procedures specified in Test Methods  for Evaluation  Solid  Waste.
Physical/Chemical Methods rsw-RA6V incorporated by reference in 260.11 of this
chapter.

       (b) Tier I feed rate screening limits.  Feed rate screening limits for metals are
specified in Appendix I of this pan as a function of terrain-adjusted effective stack height
and terrain and land use in die vicinity of the facility. Criteria for facilities that are not
eligible to comply with the screening limits are provided in paragraph (b)(7) of this section.

       (1) Noncarcinogenic metals.  The feed rates of antimony, barium, lead, mercury,
thallium, and silver in all feed streams, including hazardous waste, fuels, and industrial
furnace feed stocks shall not exceed  the screening limits specified in Appendix I of this
part

       (i) The feed rate screening limits for antimony, barium, mercury, thallium, and
silver are based on either

       (A) An hourly rolling average  as defined ui266.102(e)(6)(i)(B); or

       (B) An instantaneous limit not  to be exceeded at any time.

       (ii) The feed rate screening limit for lead is based on one of the following:

       (A) An hourly rolling average  as defined in 266.102(e)(6)(i)(B);

       (B) An averaging period of 2  to 24 hours as defined in 266.102(e)(6)(ii) with an
instantaneous feed rate limit not to exceed 10 times the feed rate that would be allowed on
an hourly rolling average basis; or

       (Q An instantaneous limit not  to be exceeded at any time.

       (2) Carcinogenic metals, (i)  The feed rates of arsenic,
                                                                    beryllium, and
chromium in all feed streams, including hazardous waste, fuels, and industrial furnace feed
                                                                  in Appendix I of
this part The feed rate of each of these metals is limited to a level such mat the sum of the
ratios of die actual feed rate to the feed rate screening limit specified in Appendix I shall not
exceed 1.0, as provided by tile following equation:

       n
       I
where:
            FRSL(i)
       n * number of carcinogenic metals
       APR  actual feed rate to the device for metal T
       FRSL  feed rate screening limit provided by Appendix I of this part for metal "i".

       (ii) The feed rate screening limits for the carcinogenic metals are based on either:

       (A) An hourly rolling average; or
                                        42

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       (B)An
exceed 10 times Ac
g period of 2 to 24 hours with an instantaneous feed rate limit not to
~ rate that would be allowed on an hourly rolling average basis.
       (3) TESH. (i) The terrain-adjusted effective stack height is detennined according to
the following equation:
where:

       Ha = Actual physical stack height
       HI = Plume rise as determined from Appendix VI of this pan as a function of stack
            flow rate and stack gas exhaust temperature.
       Tr = Terrain rise within five kilometers of the stack.

       (ii) The stack height (Ha) may not exceed good engineering practice as specified in
40CFRPan51.100(ii).

       (iii) If the TESH for a particular facility is not listed in the table in the appendices,
the nearest lower TESH listed in the table shall be used.  If the TESH is four meters or
less, a value of four meters shall be used.

       (4) Terrain type.   The screening limits are a function of whether the facility is
located in noncomplex or complex terrain.  A  device located where any part of  the
surrounding terrain within 5 kilometers of the stack equals or exceeds the elevation of the
physical stack height (Ha) is considered to be in complex terrain and the screening limits
for complex terrain apply. Terrain measurements are to be made from U.S. Geological
Survey 7.5-minute topographic maps of the area surrounding the facility.

       (5) Land use. The screening limits are a function of whether the facility is located
in an area when 'he land use is urban or rural.  To determine whether land use in  the
vicinity of the facility is urban or rural, procedures provided in Met*lpds Manual  for
Compliance  with the BIF Regulations (incorporated by reference, see  260.11) or
Guideline on Air Quality Models (incorporated by reference, see  260.1 1) shall be used.

       (6) Multiple stacks. Owners and operators of facilities with more than one on-site
stack from a boiler, industrial furnace, incinerator, or other thermal treatment unit subject to
controls of metals emissions under a RCRA operating permit or interim status controls
must comply with the screening limits for all such units assuming all hazardous waste is
fed into the device with  the worst-case stack based on dispersion characteristics. The
worst-case stack is determined from the following equation as applied to each stack:
           HVT
where:
       K = a parameter accounting for relative influence of stack height and plume rise;
       H = physical stack height (meters);
       V = stack gas flow rate (m^/second); and
       T = exhaust temperature (K).

The stack with the lowest value of K is the worst-case stack.
                                       43

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       (7) Criteria for facilities not eligible for screening limits. If any criteria below are
met, the Tier I (and Tier IT) screening limits do not apply. Owners and operators of such
facilities must comply with the Tier in standards provided by paragraph (d) of this section.

       (i) The device is located in a narrow valley less than one kilometer wide;

       (ii) The device has a stack taller than 20 meters and is located such that the terrain
rises to the physical height within one kilometer of the facility;

       (iii) The device has a stack taller man 20 meters and is located within five kilometers
of a shoreline of a large body of water such as an ocean or large lake;

       (iv) The physical stack height of any stack is less than 2.5 times the height of any
building within five building heights or five projected building widths of the stack and the
distance from the stack to the closest boundary is within five building heights or five
projected building widths of the associated building; or

       (v) The Director determines that standards based on site-specific dispersion
modeling are required.

       (8) Implementation. The feed rate of metals in each feedstream must be monitored
to ensure mat the feed rate screening limits are not exceeded.

       (c) Tier II emission rate screening limits.   Emission rate  screening limits are
specified in Appendix I as a function of terrain-adjusted effective stack height and terrain
and land use in the vicinity of the facility. Criteria for facilities that are not eligible to
comply with the screening limits are provided hi paragraph (b)(7) of this section.

       (1) Noncarcinogenic metals. The emission rates of antimony, barium, lead,
mercury, thallium, and silver shall not exceed the screening limits specified in Appendix I
of this part
v* MU> jnu*.  *uw %>iiiifM,ivn IBM* vi vovu vi u*bO*r linnau a nuiiiTii MS  IWTV* auvu uuw u>v MU>
of the ratios of the actual emission rate to the emission rate screening limit specified in
Appendix I shall not exceed 1.0, as provided by the following equation:
            ERSL(i)
                       1.0
where:
       n = number of carcinogenic metals
       AER=actual emission rate for metal "i"
       ERSL  emission rate screening limit provided by Appendix I of this pan for metal
         M|M
       (3) Implementation. The emission rate limits must be implemented by limiting feed
rates of the individual metals to levels during the trial bum (for new faculties or an interim
status facility applying for a permit) or the compliance test (for interim status faculties).
                                         44

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 The feed rate averaging periods are the same as provided by paragraphs (b)(lXi and ii) and
 (b)(2)(ii) of this section. The feed rate of metals in each feedstream must be monitored to
 ensure mat the feed rate limits for the feedstreams specified under 266.102 or 266.103
 are not exceeded.

       (4) Definitions and  limitations.  The definitions and limitations provided by
 paragraph (b) of this section for the following terms also apply to the Tier U emission rate
 screening limits provided by paragraph (c) of this section:  terrain-adjusted effective stack
 height, good engineering practice stack height, terrain type, land use, and criteria for
 facilities not eligible to use the screening limits.

       (5) Multiple stacks,  (i) Owners and operators of facilities with more than one on-
 site stack from a boiler, industrial furnace, incinerator, or other thermal treatment unit
 subject to controls on metals emissions under a RCRA operating permit or interim status
 controls must comply with the emissions screening limits for any such stacks assuming all
 hazardous waste  is fed into the device with the worst-case stack based on dispersion
 characteristics.

       (ii) The worst-case stack is determined by procedures provided in paragraph (b)(6)
 of this section.

       (iii) For each metal, the total emissions of the metal from those stacks shall not
 exceed the screening limit for the worst-case stack.

       (d) Tier III site-specific risk assessment. (1) General.  Conformance with the Tier
 m metals controls must be demonstrated by emissions testing to determine die emission
 rate for each metal, ah* dispersion modeling to predict the maximum annual average off-site
 ground level  concentration for each metal, and a demonstration that acceptable ambient
 levels are not exceeded.

       (2) Acceptable ambient levels.  Appendices IV and V of this pan list the acceptable
 ambient levels for purposes of this rule. Reference air concentrations (RACs) are listed for
 the noncarcinogenic metals and 10~5 risk-specific doses  (RSDs) are listed for the
 carcinogenic  metals. The RSD for a metal is the acceptable ambient level for that metal
 provided that only one of the four carcinogenic metals  is emitted.  If more  than one
 carcinogenic metal is emitted, the acceptable ambient level for the carcinogenic metals is a
 fraction of the RSD as described u paragraph (d)(3).

       (3) Carcinogenic metals.   For the carcinogenic metals, arsenic, cadmium,
 beryllium, and chromium, the sum of the ratios of the predicted maximum annual average
off-site ground level concentrations (except that on-site concentrations must be considered
 if a person resides on site) to the risk-specific dose (RSD) for all carcinogenic metals
 emitted shall not exceed 1.0 as determined by the following equation:

              Predicted Ambient Concentration t\ < 1 0

                  Risk-Specific Dose (i)
where: n = number of carcinogenic metals

      (4) Noncarcinogenic  metals.  For the noncarcinogenic metals, the predicted
maximum annual average off-site ground level concentration for each metal shall not exceed
the reference air concentration (RAQ.
                                       45

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       (5) Multiple slacks. Owners and operators of facilities with more than one cm-site
stack from a boiler, industrial furnace, uxmicrator, or other thermal treatment unit subjca to
controls on metals emissions under a RCRA operating permit or interim status controls
must conduct emissions testing and dispersion modeling to demonstrate that the aggregate
emissions from all such on-site stacks do not result in an exceedance of the acceptable
ambient levels.

       (6) Implementation. Under Her m, the metals controls must be implemented by
limiting feed rates of the individual metals to levels during the trial bum (for new facilities
or an interim status facility applying for a permit) or the compliance test (for interim status
facilities). The feed rate averaging periods are the same as provided by paragraphs (b)( l)(i
and ii) and (b)(2)(ii) of this section.  The feed rate of metals in each feedstream must be
monitored to ensure that the feed rate limits for the feedstreams specified under 266.102
or 266.103 are not exceeded.

       (e) Adjusted Tier I feed rate screening limits. The owner or operator may adjust the
feed rate screening limits provided by Appendix I of this part to account for site-specific
dispersion modeling. Under this approach, the adjusted feed rate screening limit for each
metal is determined by back-calculating from the acceptable ambient levels provided by
Appendices W  and V of this part using dispersion modeling to determine the maximum
allowable emission rate. This emission rate becomes the adjusted Tier I feed rate screening
limit The feed rate screening limits for carcinogenic metals are implemented as prescribed
in paragraph (b)(2) of this section.

       (f) Alternative implementation approaches.  (1) The Director may approve on a
case-by-case basis approaches to implement the Tier n or Tier m metals emission limits
provided by paragraphs (c) or (d) of this section alternative to monitoring the feed rate of
metals in each feedstream.

       (2) The emission limits provided by paragraph (d) of this  section must be
determined as follows:

       (i) For each noncarcinogenic metal, by back-calculating from the RAC provided in
Appendix IV of mis part to determine the allowable emission rate for each metal using the
dilution factor for the maximum annual average ground level concentration predicted by
dispersion modeling in conformance with paragraph (h) of this section; and

       (ii) For each carcinogenic metal, by:

       (A) Back-calculating from the RSD provided in Appendix V of this part to
determine the allowable emission rate for each metal if that metal were the only carcinogenic
metal emitted using the dilution factor for the maximum annual average ground level
concentration predicted by dispersion modeling in conformance with paragraph (h) of this
section; and

       (B) If more than one carcinogenic metal is emitted, selecting an emission limit for
each  carcinogenic  metal not to exceed the  emission rate determined by paragraph
(f)(2)(ii)(A) of this section such that the sum for all carcinogenic metals of the ratio of the
selected emission limit to the emission rate determined by mat paragraph does not exceed
1.0.
                                       46

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       (g) Emissions testing.  (1) General.  Emissions testing for metals shall be
conducted using die Multiple Metals Train as described in Methods Manual for Compliance
wife the BIF Regulations (incorporated by reference, see  260.11).

       (2) Hexavalent chromium. Emissions of chromium are assumed to be hexavalent
chromium unless the owner or operator conducts emissions testing to determine hexavalent
chromium emissions using procedures prescribed in Methods Manual for Conqpliance wj*h
the BIF Regulations (incorporated by reference, see  260.11).

       (h) Dispersion modeling. Dispersion modeling required under this section shall be
conducted according to methods recommended in Guideline on Air Quality Models
(Revised), the "Hazardous Waste Combustion Air Quality Screening Procedure" described
in Methods Manuaj  for Compliance with the BIF Regulations, or "EPA SCREEN
Screening Procedure" as described in Screening Procedures for Estimating Air Quality
Impact of Stationary Sources (all three documents are incorporated by reference,  see
260.11)  to predict the maximum annual average off-site ground level concentration.
However, on-site concentrations must be considered when a person resides on-site.

       (i) Enforcement. For the purposes of permit enforcement, compliance with the
operating requirements specified in the permit (under  266.102) will be regarded as
compliance with this section. However, evidence that compliance with those permit
conditions is insufficient to ensure compliance with the requirements of mis section may be
"information" justifying modification or revocation and re-issuance of a permit under 
270.41 of this chapter.

266.107 Standards to  control  hydrogen chloride  (HCI) and chlorine (CIj)
emissions.

       (a) General. The owner or operator must comply with the hydrogen chloride (HQ)
and chlorine (Cl2) controls provided by paragraphs (b), (c), or (d)  of this section.

       (b) Screening limits. (I) Tier I feed rate screening limits. Feed rate screening limits
are specified for total chlorine in Appendix D. of this part as a function of terrain-adjusted
effective stack height and terrain and land use in the vicinity of the facility.  The feed rate of
total chlorine and chloride, both organic and inorganic, in all feed streams, including
hazardous waste, fuels, and industrial furnace feed stocks shall not exceed the levels
specified.

       (2) Tier II emission rate screening limits. Emission rate screening limits for HCI
and Q2 are specified in Appendix in of mis part as a function of terrain-adjusted effective
stack height and terrain and land use in the vicinity of the facility. The stack emission rates
of HQ and Q2 shall not exceed the levels specified

       (3) Definitions and limitations.  The definitions  and limitations provided by
266.106(b) for the following terms also apply to the screening limits provided by this
paragraph: terrain-adjusted effective stack height, good engineering practice stack height,
terrain type, land use, and criteria for facilities not eligible to use the screening limits.

       (4) Multiple stacks. Owners and operators of facilities with more than one on-site
stack from a boiler, industrial furnace, incinerator, or other thermal treatment unit subject to
controls on HQ or Q2 emissions under a RCRA  operating permit or interim status controls
must.comply with the Tier I and Tier n screening limits for those stacks assuming all
                                      47

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hazardous waste is fed into die device witii die worst-case stack based on dispersion
characteristics.

       (i) The worst-case stack is determined by'procedures provided in 266.106(b)(6).

       (ii) Under Tier I, die total feed rate of chlorine and chloride to all subject devices
shall not exceed die screening limit for die worst-case stack.

       (iii) Under Tier n, die total emissions of HQ and Q2 from all subject stacks shall
not exceed die screening limit for me worst-case stack.

       (c) Tier III site-specific risk assessment. (1) General. Conformance with die Tier
ID controls must be demonstrated by emissions testing to determine die emission rate for
HQ and Cl2 air dispersion modeling to predict die maximum annual average off-site
ground level concentration for each compound, and a demonstration tiiat acceptable ambient
levels are not exceeded.

       (2) Acceptable ambient levels.  Appendix IV of this part lists die reference air
concentrations (RACs) for HQ (7 micrograms per cubic meter) and Q2 (0.4 micrograms
per cubic meter).

       (3) Multiple stacks. Owners and operators of facilities witit more than one on-site
stack from a boiler, industrial furnace, incinerator, or other thermal treatment unit subject to
controls on HQ or Q2 emissions under a RQIA operating permit or interim status controls
must conduct emissions testing and dispersion modeling to demonstrate mat die aggregate
emissions from all such on-site stacks do not result in  an exceedance of die acceptable
ambient levels for HQ and Q2-

       (d) Averaging periods. The HQ and Cl2 controls are implemented by limiting die
feed rate of total chlorine and chloride in all feedstreams, including hazardous waste, fuels,
and industrial furnace feed stocks. Under Tier 1, die feed rate of total chloride and chlorine
is limited to die Tier I Screening Limits. Under Tier n and Tier ffl, die feed rate of total
chloride and chlorine is limited to die feed rates during die trial bum (for new facilities or an
interim status facility applying for a permit) or die compliance test (for interim status
facilities). The feed rate limits are based on either

       (i) An hourly rolling average as defined in 266.102(e)(6); or

       (ii) An instantaneous basis not to be exceeded at any time.

       (e) Adjusted Tier I feed rate screening limits. The owner or operator may adjust die
feed rate screening limits provided by Appendix I of this pan to account for site-specific
dispersion modeling.  Under tiiis approach, die adjusted feed rate screening limit is
determined by back-calculating from die acceptable ambient level for Q2 provided by
Appendix IV of this pan using dispersion modeling to determine die maximum allowable
emissionrate. This emission rate becomes die adjusted Tier I feed rate screening limit

        (f) Emissions testing. Emissions testing for HQ and Q2 shall be conducted using
die procedures described in Methods Manual for Compliance with die BIF Regulations
(incorporated by reference, see  260.11).

        (g) Dispersion modeling. Dispersion modeling shall be conducted according to the
provisions of 266.106(h).
                                        48

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       00 Enforcement.  For the purposes of permit enforcement, compliance with the
operating requirements specified in the permit, (under  266.102) will be regarded as
compliance with mis section. However, evidence that compliance with those permit
conditions is insufficient to ensure compliance with the requirements of this section may be
"information" justifying modification or revocation and re-issuance of a permit under 
270.41 of this chapter.

 266.108 Small  quantity en-site burner exemption.

       (i) Exempt quantities. Owners and operators of facilities that bum hazardous waste
in an on-site boiler or industrial furnace are exempt from the requirements of this section
provided that:

       (1) The quantity of hazardous waste burned in a device for a calendar month does
not exceed the limits provided in the following table based on the terrain-adjusted effective
stack height as defined in  266.106(b)(3):
                                      49

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           Exempt Quantities for Small Quantity Burner Exemption
Terrain-Adjusted
 Effective Stack
Height of Device
    (Meters^
  Allowable
  Hazardous
Waste Burning
     Rate
(Gallons/Mo.)
Oto3.9
4.0 to 5.9
6.0 to 7.9
8.0 to 9.9
10.0 to 11.9
12.0 to 13.9
14 .0 to 15.9
16.0 to 17.9
18.0 to 19.9
20.0 to 21.9
22.0 to 23.9
24.0 to 25.9
26.0 to 27.9
28.0 to 29.9
30.0 to 34.9
35.0 to 39.9
0
13
18
27
40
48
59
69
76
84
93
100
110
130
140
170
Terrain-Adjusted
 Effective Stack
Height of Device
    (Meters^
                                        40.0 to 44.9
                                        45.0 to 49.9
                                        SO.O to 54.9
                                        55.0 to 59.9
                                        60.0 to 64.9
                                        65.0 to 69.9
                                        70.0 to 74.9
                                        75.0 to 79.9
                                        80.0 to 84.9
                                        85.0 to 89.9
                                        90.0 to 94.9
                                        95.0 to 99.9
                                        100.0 to 104.9
                                        105.0 to 109.9
                                        110.0 to 114.9
                                        115.0 or greater
  Allowable
  Hazardous
Waste Burning
     Rate
                                         210
                                         260
                                         330
                                         400
                                         490
                                         610
                                         680
                                         760
                                         850
                                         960
                                         1,100
                                         1,200
                                         1,300
                                         1,500
                                         1,700
                                         1,900
                                  50

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       (2) The maximum hazardous waste firing rate does not exceed at any time 1 percent
of the total fuel requirements for the device (hazardous waste plus other fuel) on a volume
basis;

       (3) The hazardous waste has a minimum heating value of 5,000 Btu/lb, as
generated; and

       (4) The hazardous waste fuel does not contain (and is not derived from) EPA
Hazardous Waste Nos. F02Q, F021, F022,  F023, F026, or F027.

       (b) Mixing with nonhazardous fuels. If hazardous waste fuel is mixed with a
nonhazardous fuel, the quantity of hazardous waste before such mixing is used to comply
with paragraph (a).

       (c) Multiple stacks. If an owner or operator burns hazardous waste in more than
one pn-site boiler or industrial furnace exempt under this section, the quantity limits
provided by paragraph (a)(l) of this section are implemented according to the following
equation:
                  n
                             Quantit  Bumed/\
                       Allowable Quantity Bumed(i)  < 1.0
where:

       n means die number of stacks;

       Actual Quantity Burned means the waste quantity burned per month in device "i";

       Allowable Quantity Burned, means the maximum allowable exempt quantity for
        stack "i" from die table in (a)(l) above.

       Note:  Hazardous wastes that are subject to the special requirements for small
quantity generators under  261.5 of this chapter may be burned in an off-site device under
the exemption provided by  266.108, but must be included in the quantity determination
for the exemption.

       (d) Notification Requirements. The owner or operator of facilities qualifying for
              V burner exemption under this section must provide a one-time signed,
written notice to EPA indicating the following:
and
       (1) The combustion unit is operating as a small quantity burner of hazardous waste;

       (2) The owner and operator are in compliance with the requirements of this section;
       (3) The maximum quantity of hazardous waste that the facility may bum per month
as provided by 266.108(a)(l).

       (e) Recordkeeping requirements.  The owner or operator must maintain at the
facility for at least three years sufficient records documenting compliance with the
hazardous waste quantity, firing rate, and heating value limits of this section. At a
                                      51

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minimum, these records must indicate the quantity of hazardous waste and other fuel
burned in each unit per calendar month, and the heating value of the hazardous waste.

(Approved by the Office of Management and Budget under control number	)

266.109  Low risk waste  exemption.

      (a) Waiver ofDRE standard.  The ORE standard of 266.104(a) does not apply if
die boiler or industrial furnace is operated in conformance with (a)(l) of this section and the
owner or operator demonstrates by procedures prescribed in (aX2) of this section that the
burning will not result in unacceptable adverse health effects.

      (1) The device shall be operated as follows:

      (i) A minimum of SO percent of fuel fired to the device shall be fossil fuel, fuels
derived from fossil fuel, tall oil, or, if approved by the Director on a case-by-case basis,
other nonhazardous fuel with combustion characteristics comparable to fossil fuel. Such
fuels are termed "primary fuel" for purposes of this section. (Tall oil is a fuel derived from
vegetable and rosin fatty acids.)  The 50 percent primary fuel firing rate shall be determined
on a total heat or volume input basis, whichever results in the larger volume of primary fuel
fired;

       (ii) Primary fuels and hazardous waste fuels shall have a minimum as-fired heating
value of 8,000 Btu/lb;

       (iii) The hazardous waste is fired directly into the primary fuel flame zone of the
combustion chamber; and

       (iv) The device  operates in conformance  with the carbon monoxide controls
provided by 266.104(b)(l). Devices subject to the exemption provided by this section are
not eligible for the alternative carbon monoxide controls provided by 266.104(c).

       (2) Procedures to demonstrate that the hazardous waste burning will not pose
unacceptable adverse public health effects are as follows:
       (i) Identify and quantify those nonmetal compounds listed in Appendix Vffl, Part
261 of this chapter that could reasonably be expected to be present in the hazardous waste.
The constituents excluded from analysis must be identified and the basis for their exclusion
explained;

       Qi) Caiqiiptr reasonable, worst case emission rates for each constituent identified in
paragraph (aX2)(i) of this section by assuming the device achieves 99.9 percent destruction
and removal efficiency.  That is, assume that 0.1 percent of the mass weight of each
constituent fed to die device is emitted.

       (iii) For each  constituent identified in paragraph (a)(2)(i) of this section, use
emissions dispersion  modeling to predict the maximum annual average ground level
concentration of the constituent

       (A) Dispersion modeling shall be conducted using methods specified in
266.106(h).

       (B) Owners and operators of facilities with more than one on-site stack from a
boiler or industrial furnace that is exempt under this section must conduct dispersion
                                       52

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 modeling of emissions from all stacks exempt under this section to predict ambient levels
 prescribed by this paragraph.

       (iv) Ground level concentrations of constituents predicted under paragraph (a)(iii)
 of mis section must not exceed the following levels:

       (A) For the noncarcinogenic compounds listed in Appendix IV of this part, the
 levels established in Appendix IV;

       (B) For the carcinogenic compounds listed in Appendix V of this part, the sum for
 all constituents of the ratios of the actual ground level concentration to the level established
 in Appendix V cannot exceed 1.0; and

       (Q For constituents not listed in Appendix IV or V, 0.002 micrograms per cubic
 meter.

       (b) Waiver of paniculate matter standard.  The paniculate matter standard of
 266.105 does not apply if:

       (1) The DRE standard is waived under paragraph (a) of this section; and

       (2) The owner or operator complies with the Tier I metals feed rate screening limits
 provided by 266.106(b).

 266.110 Waiver of DRE trial  burn  for  boilers.

       Boilers that operate under the special operating requirements of this section, and
 that do not burn hazardous waste containing (or derived from) EPA Hazardous Waste Nos.
 F020, F021, F022, F023, FO26, or F027, are considered to be in conformance with the
 DRE standard of 266.104(a), and a trial burn to demonstrate DRE is waived. When
 burning hazardous waste:

       (a) A minimum of 50 percent of fuel fired to the boiler shall be fossil fuel, fuels
 derived from fossil fuel, tall oil, or, if approved by the Director on a case-by-case basis,
 other nonhazardous fuel with combustion characteristics comparable to fossil fuel. Such
 fuels are termed "primary fuel" for purposes of this section. (Tall oil is a fuel derived from
vegetable and rosin tatty acids.) The 50 percent primary fuel firing rate shall be determined
 on a total heat or volume input basis, whichever results in the larger volume of primary fuel
 fired;

       (b) Boiler load shall not be less than 40 percent Boiler load is the ratio at any time
 of the total heat input to the maxinnim design heat input;

       (c) Primary fuels and hazardous waste fuels shall have a minimum as-fired heating
value of 8,000 Btu/lb, and each material fired in a burner where hazardous waste is fired
 must have a heating value of at least 8,000 Btu/lb, as-fired;

       (d) The device shall operate in conformance with the carbon monoxide standard
provided by 266.104(b)(l).  Boilers subject to the waiver of the DRE trial burn provided
 by this section are not eligible for the alternative carbon monoxide standard provided by
266.104(c);
       (e) The boiler must be a wateitube type boiler that does not feed fuel using a stoker
or stoker type mechanism? and
                                       53

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       (f) The hazardous waste shall be fired directly into the primary fuel flame zone of
the combustion chamber with an air or steam atomization firing system, mechanical
atomization system, or a rotary cup atomization system under the following conditions:

       (1) Viscosity. The viscosity of the hazardous waste fuel as-fired shall not exceed
300 SSU;

       (2) Particle size.  When a high pressure air or steam atomizer, low pressure
atomizer, or mechanical atomizer is used, 70%  of the hazardous waste fuel must pass
through a 200 mesh (74 micron) screen, and when a rotary cup atomizer is used, 70% of
the hazardous waste must pass through a 100 mesh (150 micron) screen;

       (3) Mechanical atomization systems.  Fuel pressure within a mechanical atomization
system and fuel flow rate shall be maintained within the design range taking into account
die viscosity and volatility of the fuel;

       (4) Rotary cup  atomization systems.  Fuel flow rate through a rotary cup
atomization system must be maintained within the design range taking into account the
viscosity and volatility of the fuel.

 266.111  Standards for direct transfer.

       (a) Applicability. The regulations in this section apply to owners and operators of
boilers and industrial furnaces subject to 266.102 or 266.103 if hazardous waste is
directly transferred from a transport vehicle to a boiler or industrial furnace without the use
of a storage unit

       (b) Definitions.  (1) When used in this section, the following terms have the
meanings given below:                                                r

       Direct transfer equipment means any device (including but not limited to, such
devices as piping, fittings, flanges, valves, and pumps) that is used to distribute, meter, or
control the flow of hazardous waste between a container  (i.e.,  transport vehicle)  and a
boiler or industrial furnace.

       Container means any portable device in which hazardous waste is transported,
stored, treated, or otherwise handled, and includes transport vehicles that are containers
themselves (e.g., tank trucks, tanker-trailers, and rail tank cars), and containers placed on
or in a transport vehicle.

       (2) This section references several requirements provided in Subparts I and I of
Parts 264 and 265. For purposes of this section, the term "tank systems" in  those
referenced requirements means direct transfer equipment as defined in paragraph (b)(l) of
mis section.

       (c) General operating requirements. (1) No direct transfer of a pumpable hazardous
waste shall be conducted from an open-top container to a boiler or industrial furnace.

       (2) Direct transfer equipment used for pumpable hazardous waste shall always be
closed, except when necessary to add or  remove  the waste, and shall not be opened,
handled, or stored in a manner that may cause any rupture or leak.
                                        54

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o
       (3) The direct transfer of hazardous waste to a boiler or industrial furnace shall be
 conducted so that it does not

       (i) Generate extreme heat or pressure, fire, explosion, or violent reaction;

       (ii) Produce uncontrolled toxic mists, fumes, dusts, or gases in sufficient quantities
 to threaten human health;

       (iii) Produce uncontrolled flammable fumes or gases in sufficient quantities to pose
 a risk of fire or explosions;

       (iv) Damage  the structural integrity of the container or direct transfer equipment
 containing the waste;

       (v) Adversely affect the capability of the boiler or industrial furnace to meet the
 standards provided by 266.104 through 266.107; or

       (vi) Threaten human health or the environment

       (4) Hazardous waste shall not be placed in direct transfer equipment if it could
 cause the equipment or its secondary containment system to rupture, leak, corrode, or
 otherwise fall.

       (S) The owner or operator of the facility shall use appropriate controls and practices
 to prevent spills and overflows from the direct transfer equipment or its secondary
 containment systems. These include at a minimum:

       (i) Spill prevention controls (e.g., check valves, dry discount couplings); and

       (ii) Automatic waste feed cutoff to use  if a leak or spill occurs from the direct
 transfer equipment

       (d) Areas where direct transfer vehicles (containers) are located. Applying the
definition of container under this section, owners and operators  must comply  with the
following requirements:

       (1) The containment requirements of 264.175 of this chapter;

       (2) The use and management requirements of Subpart I, Part 265 of mis chapter,
except for  265.170 and 265.174; and

       (3) The closure requirements of 264.178 of this chapter.

       (e) Direct transfer equipment. Direct transfer equipment must meet the following
requirements:

       (1) Secondary containment.  Owners and operators shall comply with the secondary
containment requirements of 265.193 of this chapter, except for paragraphs 265.193(a),
(d),(e), and (i) as follows:

       (i) For all new direct transfer equipment, prior to their being put into service; and
                                                    55

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       (H) For existing direct transfer equipment within 2 years after [the effective date of
the rule].

       (2) Requirements prior to meeting secondary containment requirements, (i) For
existing direct transfer equipment that does not have secondary containment, the owner or
operator shall determine whether the equipment is leaking or is unfit for use.  The owner or
operator shall obtain and keep on file at the facility a written assessment reviewed and
certified by a qualified, registered professional engineer in accordance with 270.1 l(d) of
this chapter that attests to the equipment's integrity by [12 months after the effective date of
this rule.]

       (ii) This assessment shall determine whether the direct transfer  equipment is
adequately designed and has sufficient structural strength and compatibility with the
waste(s) to be transferred to ensure that it will not collapse, rupture, or fail. At a minimum,
this assessment shall consider the following:

       (A) Design standard(s),  if available,  according  to which the direct  transfer
equipment was constructed;

       (B) Hazardous characteristics of the waste(s) that have been or will be handled;

       (C) Existing corrosion protection measures;

       (D) Documented age of the equipment, if available, (otherwise, an estimate of the
age); and

       (E) Results of a leak test or other integrity examination such that  the effects of
temperature variations, vapor pockets, cracks, leaks, corrosion, and erosion  are accounted
for.

       (iii) If , as a result of the assessment specified above, the direct transfer equipment is
found to  be leaking or  unfit for use, the owner or operator shall comply with the
requirements of 265.196(a) and (b) of this chapter.

       (3) Inspections and recordkeeping. (i) The owner or operator must inspect at least
once each operating hour when hazardous waste is being transferred from the transport
vehicle (container) to the boiler or industrial furnace:

       (A)  Overfill/spill  control equipment (e.g., waste-feed cutoff systems, bypass
systems, and drainage systems) to ensure that it is in good working order;

       (B) The above ground portions of the direct transfer equipment to detect corrosion,
erosion, or releases of waste (e.g., wet spots, dead vegetation); and

       (C) Data garnered from monitoring equipment and teak-detection equipment, (e.g.,
pressure and temperature gauges) to ensure that the direct transfer equipment is being
operated according to its design.

       (ii) The owner or operator must inspect cathodic protection systems, if used, to
ensure that they are functioning properly according to the schedule provided by
265.195(b) of this chapter:
                                        56

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       (iii) Records of ins
        ; record at the;
  'the inspection.
  ions made under this paragraph shall be maintained in the
y, and available for inspection for at least 3 years from the date
       (4) Design and installation of new ancillary equipment. Owners and operators must
comply with the requirements of 265.192 of this chapter.

       (5) Response to leaks or spills.  Owners and operators must comply with the
requirements of 265.1% of this chapter.

       (6) Closure.  Owners and operators must comply with the requirements of
265.197 of this chapter, except for  265.197(c)(2) through (c)(4).

(Approved by the Office of Management and Budget under control number	)

  266.112   Regulation of residues.

       A residue derived from the burning or processing of hazardous waste in a boiler or
industrial furnace is not excluded from the definition of a  hazardous  waste  under
261.4(b)(4), (7), or (8) unless the device and the owner or operator meet the following
requirements:

       (a) The device meets the following criteria:

       (1) Boilers. Boilers must bum coal and at least 50% of the heat input to the boiler
must be provided by the coal;

       (2) Ore or mineral furnaces. Industrial furnaces subject to 261.4(b)(7) must
process at least 50% by weight normal, nonhazardous raw materials;

       (3) Cement kilns.  Cement kilns must process at least 50% by weight normal
cement-production raw materials;

       (b) The  owner or operator demonstrates that the hazardous waste does not
significantly affect the residue by demonstrating conformance with either of the following
criteria:

       (1) Comparison of waste-derived residue with normal residue. The waste-derived
residue must not contain Appendix Vffl, Pan 261 constituents (toxic constituents) that
could reasonably be attributable to the hazardous waste at concentrations significantly
higher man in residue generated without burning or processing of hazardous waste, using
the following procedure. Toxic compounds mat could reasonably be attributable to burning
or processing the hazardous waste (constituents of concern) include toxic constituents in
the hazardous waste, and the 31 organic compounds listed in
that may be generated as products of incomplete combustion. Sampling and analyses i
be in conformance with procedures prescribed in Test Methods for Evaluating Solid Waste.
Physical/Chemical Methods, incorporated by reference in 260.1 l(a) of this chapter.

       (i) Normal residue.  Concentrations of toxic constituents of concern in normal
residue shall be determined based on analyses of a minimum of 10 composite samples.
The upper 95% confidence level about the mean of the concentration in the normal residue
shall be considered the statistically-derived concentration in the normal residue. If changes
in raw materials or fuels reduce the statistically-derived concentrations of the toxic
                                      57

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constituents of concern in the normal residue, the statistically-derived concentrations must
be revised or statistically-derived concentrations of toxic constituents in normal residue
must be established for a new mode of operation with the new raw material or fuel.  To
determine the upper 95% confidence level about tbe mean of die concentration in the normal
residue, the owner or operator shall use statistical procedures prescribed in "Statistical
Methodology for Bevill Residue Pc-tcnTiinatiAns** in Mf!thp^R Mqpual fop {"-^flDlPnCC with
the BIF Regu>tiflns incorporated by reference in 260.11 (a) of mis chapter.

       (ii) Waste-derived residue. Concentrations of toxic constituents of concern in
waste-derived residue shall be determined based on analysis of samples composited over a
period of not more man  24 hours.  The concentration of a toxic constituent in the waste-
derived residue is not considered to be significantly higher man in the normal residue if the
concentration in the waste-derived residue does not exceed the concentration established for
the normal residue under paragraph (b)(l)(i) of this section; or

       (2) Comparison of waste-derived residue concentrations with health-based limits.
(i) Nonmetal constituents. The concentrations of nonmetal toxic constituents of concern
(specified in paragraph (b)(l) of this section) in the waste-derived residue must not exceed
the health-based levels specified in Appendix Vn of this part If a health-based limit for a
constituent of concern is not listed in Appendix Vn of this pan, then a limit of 0.002
nricrograms per kilogram or the level of detection (using analytical procedures prescribed in
SW-846), whichever is higher, shall be used; and

       (ii) Metal constituents. The concentration of metals in an extract obtained using the
Toxicity Characteristic Leaching Procedure of 261.24 of this chapter must not exceed the
levels specified in Appendix VTI of this part; and

       (c) Records sufficient to document compliance with the provisions of this section
must be retained  for a period of three years.  At a minimum, the following shall be
recorded:

       (1) Levels of constituents in Appendix Vm, Part 261, that are present in waste-
derived residues;

       (2) If the waste-derived residue is compared with normal residue under paragraph
(bXl) of this section:

       (i) The levels of constituents in Appendix Vm, Pan 261, mat are present in normal
residues; and

       (ii) Data and information, including analyses of samples as necessary, obtained to
determine if changes in raw materials or fuels would reduce the concentration of toxic
constituents of concern in the normal residue.

PART  270--EPA  ADMINISTERED  PERMIT   PROGRAMS:     THE
HAZARDOUS WASTE PERMIT PROGRAM.

       VLInPart270:

       1. The authority citation for Pan 270 continues to read as follows:

       Authority: Sees. 1006,2002,3005,3007, and 7004 of the Solid Waste Disposal
Act, as amended by the Resource Conservation and Recovery Act of 1976, as amended (42
U.S.C. 6905,6912, 6925,6927, and 6974.
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       2. Part 270 is amended by adding 270.22 to read as follows:

 270.22    Specific  Part B  information  requirements for  boilers  and
 industrial furnaces burning  hazardous waste.

       (a) Trial burns.  (I) General. Except as provided below, owners and operators that
 are subject to the standards to control organic emissions provided by 266.104 of this
 chapter, standards to control paniculate matter provided by 266.105 of this chapter,
 standards to control metals emissions provided by 266.106 of this chapter, or standards to
 control hydrogen chloride or chlorine gas emissions provided by 266.107 of this chapter
 must conduct a trial bum to demonstrate confonnance with those standards and must
 submit a trial burn plan or the results of a trial burn, including all required determinations,
 in accordance with 270.66.

       (i) A trial burn to demonstrate confonnance with a particular emission standard may
 be waived under provisions of 266.104 through 266.107 of this chapter and paragraphs
 (a)(2) through (a)(5) of this section; and

       (ii) The owner or operator may submit data in lieu of a trial burn, as prescribed in
 paragraph (a)(6) of this section.

       (2) Waiver of trial burn for ORE. (i) Boilers  operated under special operating
 requirements. When seeking to be permitted under 266.104(a)(4) and 266.110 of this
 chapter that automatically waive the DRE trial bum, the owner or operator of a boiler must
 submit documentation that the boiler operates under the special operating requirements
 provided by 266.110 of this chapter.

       (ii) Boilers and industrial furnaces burning low risk waste. When seeking to be
 permitted under the provisions for low risk waste provided by 266.104(a)(S) and
 266.109(a) of this chapter that waive the DRE trial  bum, the owner or operator must
 submit

       (A) Documentation that the device is operated in confonnance with the requirements
of 266.109(a)(l) of this chapter,

       (B) Results of analyses of each waste to be burned, documenting the concentrations
of nonmetal compounds listed in Appendix Vm of Pan 261 of tilts chapter, except for
 those constituents that would reasonably not  be expected to be in,the waste.  The
constituents excluded from analysis must be identified and the basis for their exclusion
explained. The analysis must rely on analytical techniques specified in Test Methods for
the Evaluation of Solid Wa.fle- Physicft^ Chemical MsftllftdS (incorporated by reference, see
260.11).

       (Q Documentation of hazardous waste firing rates and calculations of reasonable,
worst-case emission rates of each constituent identified in paragraph (a)(l)(ii)(B) of this
section using procedures provided by 266.109(a)(2)(ii) of this chapter,

       (D) Results of emissions dispersion modeling for  emissions identified in
paragraphs (a)(2)(ii)(C) of this  section using modeling procedures prescribed by
266.106(h) of mis chapter. The Director will review the emission modeling conducted by
the applicant  to determine confonnance with these procedures. The Director will either
approve the modeling or determine that alternate or supplementary modeling is appropriate.
                                                   59

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       (E) Documentation that the maimnm annual average ground level concentration of
each constituent identified in paragraph (a)(2)(ii)(B) of this section quantified in
confonnance with paragraph (a)(2)(u))D) of this section does not exceed the allowable
ambient level established in Appendices IV of V of Part 266.  The acceptable ambient
concentration for emitted constituents for which a specific Reference Air Concentration has
not been established in Appendix IV or Risk-Specific Dose has not been established in
Appendix V is 0.09 rmcrograms per cubic meter, as noted in the footnote to Appendix IV.

       (3) Waiver of trial burn for metals. When seeking to be permitted under the Tier I
(or adjusted Tier I) metals feed rate screening limits provided by 266.106(b) and (e) of
this chapter that control metals emissions without requiring a trial burn, the owner or
operator must submit:

       (i) Documentation of the feed rate of hazardous waste, other fuels, and industrial
furnace feed stocks;

       (u) Documentation of the concentration of each metal controlled by 266.l06(b) or
(e) of this chapter in the hazardous waste, other fuels, and industrial furnace feedstocks,
and calculations of the total feed rate of each metal;

       (iii) Documentation of how the applicant will ensure that the Tier I feed rate
screening limits provided by 266.106(b) or (e) of this chapter will not be exceeded during
the averaging period provided by that paragraph;

       (iv) Documentation to support the determination of the terrain-adjusted effective
by 266.106(b)(3) through (b)(5) of this chapter,

       (v) Documentation of compliance with the provisions of 266.106(b)(6),  if
applicable, for facilities with multiple stacks;

       (vi)  Documentation that the facility does not fail the criteria provided by
266.106(b)(T) for eligibility to comply with the screening limits; and

       (vii) Proposed sampling and metals analysis plan for the hazardous waste, other
fuels, and industrial furnace feed stocks.

       (4) Waiver of trial burn for paniculate matter. When seeking to be permitted under
the low risk waste provisions of 266.109(b) which waives the paniculate standard (and
trial burn to demonstrate confonnance with the paniculate standard), applicants must
submit documentation supporting confonnance with paragraphs (a)(2Xu) and (aX3) of this
section.

       (5) Waiver of trial burn for HCl and CQ.  When seeking to be permitted under the
Tier I (or adjusted Tier I) feed rate screening limits for total chloride and chlorine provided
by 266.107(b)(l) and (e) of this chapter that control emissions of hydrogen chloride
(HCl) and chlorine gas (Q2) without requiring a trial bum, the owner or operator must
submit:

       (i) Documentation of the feed rate of hazardous waste, other fuels, and industrial
furnace feed stocks;

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       (ii) Documentation of the levels of total chloride and chlorine in the hazardous
waste, other fuels, and industrial furnace feedstocks, and calculations of the total feed rate
of total chloride and chlorine;

       (iii) Documentation of how the applicant will ensure that the Tier I (or adjusted Her
I) feed rate screening limits provided by 266.107(b)(l) or (e) of this chapter will not be
exceeded during the averaging period provided by that paragraph;

       (iv) Documentation to support the determination of the terrain-adjusted effective
stack height, good engineering practice stack height, terrain type, and land use as provided
by 266.107(b)(3) of this chapter,

       (v) Documentation  of compliance with the provisions of 266.107(b)(4), if
applicable, for facilities with multiple stacks;

       (vi) Documentation that the facility does not  fail the criteria provided  by
266.107(b)(3) for eligibility to comply with the screening limits; and

       (vii) Proposed sampling and analysis plan for total chloride and chlorine for the
hazardous waste, other fuels, and industrial furnace feedstocks.

       (6) Data in lieu of a trial burn. The owner or operator may seek an exemption from
die trial bum requirements to demonstrate conformance with 266.104 through 266.107
of this chapter and 270.66 by providing the information required by 270.66  from
previous compliance testing of the device in conformance with 266.103 of this chapter, or
from compliance testing or trial or operational bums of similar boilers or industrial furnaces
burning similar hazardous wastes under similar conditions.  If data from a similar device is
used to support a trial burn waiver, the design and operating information required  by
270.66 must be provided for both the similar device and the device to which the data is to
be applied, and a  comparison of the design and operating  information must be provided.
The Director shall approve  a permit application without a trial bum if he finds that the
hazardous wastes are sufficiently similar, the devices are sufficiently similar, die operating
conditions are sufficiently similar, and the data from other compliance tests, trial bums, or
operational burns are adequate to  specify (under  266.102 of this chapter) operating
conditions that will ensure conformance with 266.102(c) of this chapter. In addition, the
following information shall be submitted:

       (i) For a waiver from any trial bum:

       (A) A description and analysis of the hazardous waste to be burned compared with
the hazardous waste for which data from compliance testing, or operational or trial burns
are provided to support the contention that a trial bum is not needed;

       (B) The design and operating conditions of the boiler or industrial furnace to be
used, compared with that for which comparative bum data are available; and

       (Q Such supplemental information as the Director finds necessary to achieve the
purposes of this paragraph.

       (ii) For a waiver of the DRE trial bum, the basis for selection of POHCs usedin the
other trial or operational bums which demonstrate compliance with the DRE performance
standard in 266.104
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  waste for which a permit is sought, and any differences from the POHCs in the hazardous
  waste for whkhbmi data are provided.

        (b) Alternative HC limit for industrial furnaces with organic matter in raw materials.
  Owners and operators of industrial furnaces requesting an alternative HC limit under
  266.104(f) of mis chapter shall submit the following information at a minimum:

        (1) Documentation that the furnace is designed and operated to minimize HC
  emissions from fuels and raw materials;

        (2) Documentation of the proposed baseline flue gas HC (and CO) concentration,
'  including data  on HC (and CO)  levels during tests when the facility produced normal
  products under normal operating conditions from normal raw materials while burning
  normal fuels and when not burning hazardous waste;

        (3) Test burn  protocol to confirm the baseline HC (and CO) level including
  information on the type and flow rate of all feedstreams, point of introduction of all
  feedstreams, total organic carbon content (or other appropriate measure of organic content)
  of all nonfuel feedstreams, and operating conditions that affect combustion of fuel(s) and
  destruction of hydrocarbon emissions from nonfuel sources;

        (4) Trial bum plan to:

        (i) Demonstrate that flue gas HC (and CO) concentrations when burning hazardous
  waste do not exceed the baseline HC (and CO) level; and

        (ii) Identify the types and concentrations of organic compounds listed in Appendix
  Yin, Part 261 of  this chapter, that are emitted when burning hazardous waste in
  conformance with procedures prescribed by the Director,

        (S) Implementation plan to monitor over time changes in the operation of the facility
  that could reduce the baseline HC level and procedures to periodically confirm the baseline
  HC level; and

        (6) Such other information as the Director finds necessary to achieve the purposes
  of this paragraph.

        (c) Alternative metals implementation approach.  When seeking to be permitted
  under an alternative metals implementation approach under 266.106(0 of this chapter, the
  owner or operator must submit documentation specifying how the approach  ensures
  compliance with the metals emissions  standards of 266.106(c) or (d) and how the
  approach can be effectively implemented and monitored.  Further, the owner or operator
  shall provide such other information mat the Director finds necessary to achieve the
  purposes of this paragraph.

        (d) Automatic waste feed cutoff system. Owners and operators shall submit
  information describing the automatic waste feed cutoff system, including any pre-alarm
  systems mat may be used.

        (e) Direct transfer. Owners and operators mat use direct transfer operations to feed
  hazardous waste from transport vehicles (containers, as defined in 266.111 of this
      ter) directly to the boiler or industrial furnace shall submit information supporting
      ormance with the standards for direct transfer provided by 266.111 of this chapter.
                                        62

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                   (0 Residues. Owners and operators that claim that their residues are excluded from
             regulation under the provisions of 266.112 of this chapter must submit information
             adequate to demonstrate conformance with those provisions.

             (Approved by the Office of Management and Budget under control number	)

                   3. In 270.42, paragraph (g) is revised to read as follows:

             270.42  Permit modifications at  the request of the permittee.
o
       (g) Newfy regulated wastes and units. (1) The permittee is authorized to continue
to manage wastes listed or identified as hazardous under Pan 261  of this chapter, or to
continue to manage hazardous waste in units newly regulated  as hazardous waste
management units, if:

       (i) The unit was in existence as a hazardous waste facility with respect to the newly
listed or characterized waste or newly regulated waste management unit on the effective
date of the final rule listing or identifying the waste, or regulating the unit;

       (ii) The permittee submits a Class 1 modification request on or before the date on
which the waste or unit becomes subject to the new requirements;

       (iii) The permittee is in compliance with the applicable standards of 40 CFR Parts
265 and 266 of this chapter,

       (iv) In the case of Classes 2 and 3 modifications, the permittee also submits a
complete modification request within 180 days of the effective date of the rule listing or
identifying the waste, or subjecting the unit to RCRA Subtitle C management standards;

       (v) In the case of land disposal units, die permittee certifies that each such unit is in
compliance with all  applicable requirements of Pan 265 of this chapter for groundwater
monitoring and financial responsibility on the date 12 months after the effective date of the
rule identifying or listing the waste as hazardous, or regulating the unit as a hazardous
waste management unit If the owner or operator fails to certify compliance with all these
requirements, he or she will lose authority to operate under this section.

       (2) New wastes or units added to a facility's permit under this subsection do not
constitute expansions for the purpose of the 25 percent capacity expansion limit for Class 2
modifications.
                   4. In 270.42, Appendix I is amended by revising Title L, "Incinerators", items 1
            through 7 to read as follows:

            APPENDIX  I TO  SECTION  270.42  -  CLASSIFICATION  OF  PERMIT
            MODIFICATIONS
                                                  63

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          *    
L. Incinerators, Boilers, and Industrial Furnaces
 1. Changes to increase by more than 25% any of the following limits Bnthrrafd in the
    permit: Atr*malfcdi^liiiiit,afee******
 2. Changes to increase byupto2S%anyofthe following limits authorized in the permit:
    A thermal feed rate limit, a feedstream feed rate liinit, a chlorine/chloride fieed rate limit,
    a metal feed rate limit, or an ash feed rate limit. The Director win require a new trial
    burn to substantiate compliance with the regulatory performance standards unless this
    demonstration can be made through other means[[[
 3. Modification of an incinerator, boiler, or industrial rJirmveiniU by changing the internal
    size or geometry of the primary or secondary combustion units, by adding a primary or
    secondary combustion unit, by substantially changing the design of any component used
    to remove HO/Clj. metals, or paniculate from the combustion gases, or by changing
    other features of the incinerator, boiler, or industrial rurnace mat could affect its
    capability to nxet the regulatory performance standards. The Director will require a new
    trial burn to substantiate compliance with the regulatory performance standards unless
    this demonstration can be made through other means.
  4. Modification of an incinerator, boiler, or industrial fimaceimUrn a inaniw that would
    not likely affect the capability of the unit to meet the regulatory performance standards
    but which would change the operating conditions or monitorir^ requirements specified in
    the permit. The Director may require a new trial bum to demonstrate compliance with
    the regulatory performance  standards[[[
  5. Operating requirements:
    a. Modification of the limits specified in the permit for minimum or maximum
      combustion gas temperature, minimum combustion gas residence time, oxygen
      eonceiantictt mite secondary cmbustto                                      '
      hydrocarbon concentration, maximum ten^eranire at tteuikt to the particiilate matter
      emission control system, or operating parameters for the air pollution control system.
      The Director will require a new trial burn to substantiate compliance wim the
      regulatory performance standards unless this demonsttatkn can be niad^ through omer
      means...............................	
          *
  6. Burning different w	
    a. If the waste contains a POHCtbat is more difficult to bom than authorised by the
      permit or if burning of the waste requires compliance with different regulatory
      performance standards than specified in the permit. The Dutctor will require a new trial
      bum to Mtettntiate compliance wim the regulatory p
      demonstration can be made through other means.,
    b. If the waste does not contain a POHC that is more difficult to burn than authorized by
      the permit and if burning of the waste does not require compliance with different
      regulatory performance standards than specified in the permit...................-..-.
Note: See $270.42(g) for modification procedures to be used for the management of newly
  \tftt^ of "Verified waw*
  7. Shakedown and trial burn:
*      
    b. Authorization of up to aa additional 720 hours of waste burning during the shakedown
      period for determining operational readiness after constniction,wu1i the prior approval
      of  the Director......
   *   
  8.!

                                iyr^ofT^
 1Qass 1 modifications requiring prior Agency approval.
                                                                                         3



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       5. Pan 270 is amended by adding 270.66 to read as follows:

270.66   Permits for  boilers  and industrial furnaces burning  hazardous
waste.

       (a) General. Owners and operators of new boilers and industrial furnaces (those
not operating under the interim status standards of 266.103 of this chapter) are subject to
paragraphs (b) through (f) of this section. Boilers and industrial furnaces operating under
the interim status standards of 266. 103 of this chapter are subject to paragraph (g) of this
section.

       (b) Permit operating periods for new boilers and industrial furnaces. A permit for a
new boiler or industrial furnace shall specify  appropriate conditions for the following
operating periods:

       (1) Pretrial burn period. For the period beginning with initial introduction of
hazardous waste and ending with initiation of the trial bum, and only for the minimum time
required to bring the boiler or industrial furnace to a point of operation readiness to conduct
a trial burn, not to exceed 720 hours operating time when burning hazardous waste, the
Director must establish in the Pretrial Burn Period of the permit conditions, including but
not limited to, allowable hazardous waste feed rates and operating conditions. The Director
may extend the duration of this operational period once, for up to 720 additional hours, at
the request of the applicant when good cause is shown.  The permit may be modified to
reflect the extension according to 270.42.

       (i) Applicants must submit a statement, with Part B of the permit application, that
suggests the conditions necessary  to  operate in compliance with the standards of
266.104  through 266.107 of this chapter during this period.  This statement should
include, at a minjrnutyi, restrictions on the applicable operating requirements identified in
             266.102(e) of this chapter.

                   (ii) The Director will review this statement and any other relevant information
             submitted with Part B of the permit application and specify requirements for this period
             sufficient to meet the performance standards of 266.104 through 266.107 of mis chapter
             based on his/her engineering judgment

                   (2) Trial burn period. For the duration of the trial burn, die Director must establish
             conditions in die permit for the purposes of determining feasibility of compliance with the
             performance standards of 266.104 through 266.107 of this chapter and determining
             adequate operating conditions under 266.102(e) of this chapter. Applicants must propose
             a trial burn plan, prepared under paragraph (c) of this section, to be submitted with Part B
             of the permit application.

                   (3) Post-trial burn period, (i) For the period immediately following completion of
             the trial burn, and only for the minimum period sufficient to allow sample analysis, data
             computation, and submission of the trial burn results by the applicant, and review of die
             trial bum results and modification of the facility permit by the Director to reflect the trial
             burn results, die Director will establish the operating requirements most likely to ensure
             compliance with the performance standards of 266.104 through 266.107 of this chapter
             based on his engineering judgment

                   (ii) Applicants must submit a statement, with Pan B of the application, that
             identifies the conditions necessary to operate during this period in compliance with the

-------
performance standards of 5266.104 through 266.107 of this chapter. This statement
should include, at a primmnm, restrictions on the operating requirements provided by
266.102(c) of this chapter.

       (iii) The Director will review this statement and any other relevant information
submitted with Part B of the permit application and specify requirements for this period
sufficient to meet the performance standards of 266. 104 through 266.107 of this chapter
based on Ms/her engineering judgment

       (4) Final permit period. For the final period of operation, the Director will develop
operating requirements  in conformance with 266.102(e)  of this chapter that reflect
conditions in the trial burn plan and are likely to ensure compliance with the performance
standards of 266.104 through 107 of this chapter. Based on the trial burn results, the
Director shall make any necessary modifications to the operating requirements to ensure
compliance with the performance standards.  The permit  modification shall proceed
according to 270.42.

       (c) Requirements for trial burn plans.  The trial burn plan must include the
following information. The Director, in reviewing the trial burn plan, shall evaluate the
sufficiency of the information provided and may require the applicant to supplement this
information, if necessary, to achieve the purposes of mis paragraph:

       (1) An analysis of each feed stream, including hazardous waste, other fuels, and
industrial furnace feed stocks, as fired, that includes:

       (i) Heating value, levels of antimony, arsenic, barium, beryllium, cadmium,
chromium, lead, mercury, silver, thallium, total chlorine/chloride, and ash;

       (U) Viscosity or description of the physical form of die feed stream;

       (2) An analysis of each hazardous waste, as fired, including:

       (i) An identification of any hazardous organic constituents listed in Appendix Vffi,
Part 261, of this chapter mat are present in the feed stream, except that the applicant need
not analyze for constituents listed in Appendix VHI that would reasonably not be expected
to be found in the hazardous waste. The constituents excluded from analysis must be
identified and the basis for their exclusion explained. The  analysts must be conducted in
accordance with analytical techniques specified in Test Methods for the Evaluation of Solid
Waste. Physical/ Chemical Methods (incorporated by reference, see 270.6), or their
equivalent

       (ii) An approximate quantification of the hazardous constituents identified in the
hazardous waste, within the precision produced by the analytical methods specified in lea
Mfftfofwfo fpr yhe Evaluation of Solid Waste. Pfc|yeir!fl|/f!hemicfll frff-thnris finr-firpnratcd by
reference, see 270.6), or other equivalent

       (iii) A description of blending
hazardous waste, including a detailed analysis of the h
       (iii) A description of blending procedures, if applicable, prior to firing the
                                               azardous waste prior
analysis of the material with which the hazardous waste is blended, and blending ratios.
                                                 waste prior to blending, an
(3) A detailed engineering description of the boiler or industrial furnace, including:

6) Manufacturer's name and model number of the boiler or industrial furnace;
                                66

-------
  H
o
       (ii) Type of baiter or industrial furnace;

       (iii) Maximum design capacity in appropriate units;

       (iv) Description of the feed system for the hazardous waste, and, as appropriate,
other fuels and industrial furnace feedstocks;

       (v) Capacity of hazardous waste feed system;

       (vi) Description of automatic hazardous waste feed cutoff system(s); and

       (vii) Description of any air pollution control system; and

       (vii) Description of stack gas monitoring and any pollution control monitoring
systems.

       (4) A detailed description of sampling and monitoring procedures including
sampling and monitoring locations in the system, the equipment to be used, sampling and
monitoring frequency, and planned analytical procedures for sample analysis.

       (5) A detailed test schedule for each hazardous waste for which the trial bum is
planned, including date(s), duration, quantity of hazardous waste to be burned, and other
factors relevant to the Director's decision under paragraph (b)(2) of this section.

       (6) A detailed test protocol, including, for each hazardous waste identified, the
ranges of hazardous waste feed rate, and, as appropriate, the feed rates of other fuels and
industrial furnace feedstocks, and any other relevant parameters that may affect the ability
of the boiler or industrial furnace to meet the performance standards in 266.104 through
266.107 of this chapter.

       (7) A description of, and planned operating conditions for, any emission control
equipment that will be used

       (8) Procedures for rapidly stopping the hazardous waste feed and controlling
emissions in the event of an equipment malfunction.

       (9) Such other information as the Director reasonably finds necessary to determine
whether to approve the trial burn plan in light of the purposes of this paragraph and the
criteria in paragraph (b)(2) of this section.

       (d) Trial burn procedures.  (1) A trial burn must be conducted to demonstrate
conformance with the standards of 266.104 through 266.107 of this chapter under an
approved trial bum plan.

       (2) The Director shall approve a trial burn plan if he/she finds that:

       (i) The trial bum is likely to determine whether the boiler or industrial furnace can
meet the performance standards of 266.104 through 266.107 of this chapter;

       (ii) The trial bum itself will not present an imminent hazard to human health and the
environment;
                                                   67

-------
       (iii) The trial burn will help the Director to determine operating requirements to be
specified under 266.102(c) of this chapter, and

       (iv) The information sought in the trial burn cannot reasonably be developed
through other means.

       (3) The applicant must submit to the Director a certification that the trial burn has
been carried out in accordance with the approved trial burn plan, and must submit the
results of all the determinations required in paragraph (c) of this section. This submission
shall be made  within 90 days of completion of the trial burn, or later if approved by the
Director.

       (4) All data collected during any trial bum must be submitted to the Director
following completion of the trial bum.

       (5) All submissions required by this paragraph must be certified on behalf of the
applicant by the signature of a person authorized to sign a permit application or a report
under 270.11.

       (e) Special procedures for DRE trial burns.  When a DRE trial bum is required
under 266.104(a) of this chapter, the Director will specify (based on the hazardous waste
analysis data and other information in the trial bum plan) as trial Principal Organic
Hazardous Constituents (POHCs) those compounds for which destruction and removal
efficiencies must be calculated during the trial burn. These trial POHCs will be specified
by the Director based on information including his/her estimate of die difficulty of
destroying die constituents identified in the hazardous waste analysis, their concentrations
or mass in the hazardous waste feed, and, for hazardous waste containing or derived from
wastes listed  in Part 261, Subpart D of this chapter, the hazardous waste organic
constituents) identified in Appendix VH of that pan as die basis for listing.

       (f) Determinations based on trial burn.  During each approved trial bum (or as soon
after die bum as is practicable), die applicant must make die following determinations:

       (1) A quantitative analysis of die levels of antimony, arsenic, barium, beryllium,
cadmium, chromium, lead, mercury, diallium, silver, and chlorine/chloride, in die feed
streams (hazardous waste, otiier fuels, and industrial furnace feedstocks);

       (2) When a DRE trial bum is required under 266.104(a) of this chapter

       (i) A quantitative analysis of die trial POHCs in die hazardous waste feed;

       (U) A quantitative analysis of tiw stack gas for die concentration and
of die trial POHCs; and
fi^flSfi emissions
       OH) A computation of destruction and removal efficiency (DRE), in accordance widi
die DRE formula specified in 266.104(a) of this chapter,

       (3) When a trial burn for chlorinated dioxins and furans is required under
266.104(e) of tiiis chapter, a quantitative analysis of die stack gas for die concentration
and mass emission rate of the 2,3,7,8-chlorinated tetra-octa congeners of chlorinated
dibenzo-p-dioxins and furans, and a computation showing conformance widi die emission
standard.

-------
       (4) When a trial burn for particular matter, metals, or HO/C12 is required under
 266.105, 266.106(c) or (d), or 266.107 (b)(2.) or (c) of this chapter, a quantitative
 analysis of the stack gas for the concentrations and mass emissions of paniculate matter,
 metals, or hydrogen chloride (HC1) and chlorine (Cl2), and computations showing
 confonnance with the applicable emission performance standards;

       (5) When a trial bum for DRE, metals, or HG/C12 is required under 266.104(a),
 266.106(c) or (d), or 266.107(b)(2) or (c) of this chapter, a quantitative analysts of the
 scrubber water (if any), ash residues, other residues, and products for the purpose of
 estimating the fate of the trial POHCs, metals, and chlorine/chloride;

       (6) An identification of sources of fugitive emissions and their means of control;

       (7) A continuous measurement of carbon monoxide (CO), oxygen, and where
 required, hydrocarbons (HC), in the stack gas; and

       (8) Such other information as the Director may specify as necessary to ensure that
 the trial burn will determine compliance  with the performance standards in 266.104
 through 266.107 of this chapter and to establish the operating conditions required by
 266.102(e) of this chapter as necessary to  meet those performance standards.

       (g) Interim status boilers and industrial furnaces. For the purpose of determining
 feasibility of compliance with the performance standards of 266.104 through 266.107 of
 this chapter and of determining adequate operating conditions under 266.103 of this
 chapter, applicants owning or operating existing boilers or industrial furnaces operated
 under the interim status standards of 266.103 must either prepare and submit a trial burn
 plan and perform a trial burn in accordance with the requirements of this section or submit
 other information as specified in 270.22(a)(6). Applicants who submit a trial burn plan
 and receive approval before submission of the Pan B permit application must complete the
 trial burn and submit the results specified  in paragraph (f) of this section with the Pan B
 permit application.  If completion of this process conflicts with the date set for submission
 of the Pan B application, the applicant must contact the Director to establish a later date for
 submission of the Pan B application or die trial bum results. If the applicant submits a trial
 burn plan with Part B of the permit application, the trial burn must be conducted and the
results submitted within a time period prior to permit issuance to be specified by the
Director.

 (Approved by the Office of Management and Budget under control number	)

       6. 270.72 is amended by adding paragraphs (a)(6) and (b)(7) to read as follows:

 270.72 Changes  during  interim status.

       (a)     *     *     *

       (6) Addition of newly regulated units for the treatment, storage, or disposal of
hazardous waste if the owner or operator submits a revised Pan A permit application on or
before the date on which the unit becomes subject to the new requirements.

       (b)     *     *     *

       (7) Addition of newly regulated units under paragraph (a)(6) of this section.
                                       69

-------
      7. 270.73 is amended by revising paragraphs (f) and (g) to read as follows:

270.73 Termination of interim status.
      (f) For owners and operators of each incinerator facility which as achieved interim
status prior to November 8,1984, interim status terminates on November 8,1989, unless
the owner or operator of the facility submits a Part B application for aRCRA permit for an
incinerator facility by November 8,1986.

      (g) For owners or operators of any facility (other than a land disposal or an
incinerator facility) which as achieved interim status prior to November 8,1984, interim
status terminates on November 8, 1992, unless the  owner or operator of the facility
submits a Pan B application for a RCRA permit for the facility by November 8,1988.

PART  271  -  REQUIREMENTS FOR AUTHORIZATION OF  STATE
HAZARDOUS  WASTE PROGRAMS

      VIL In Part 271:

      1. The authority citation for part 271 continues to read as follows:

      Authority: 42 U.S.C 6905,6912(a), and 6926.

      2. Section 271.1(j) is amended by  adding the following entry to Table  1 in
chronological order by date of publication in the Federal Register:

271.1  Purpose and  scope.
      (i)     *      *     *

  TABLE 1. - REGULATIONS IMPLEMENTING THE HAZARDOUS AND SOLID
                       WASTE AMENDMENTS OF 1984
  December 31.1990
                     Title of regulation
Burning of Hazardous
Waste in Boilers and
 Industrial Furnaces
                   Federal Register
[insert page numbers]
                     Effective dale
June 30,1991
Appendices
                                    70

-------
                      Appendix I.  * Tier  I and Tier II  Feed Rate and Emissions
                                     Screening Limits for Metals

               Table I-A.  TIER I AND TIER II FEED  RATE  AND EMISSIONS SCREENING LIMITS
                   FOR NONCARCINOGENIC METALS FOR FACILITIES IN NONCOMFLEX TERRAIN
o
                                           Vlu for Urban At
Terrain Adjusted
Elf, Stack Ht. (o)
4
e
B
10
12
It
IB
18
20
22
2*
28
28
30
33
*0
45
50
35
60
83
70
T5
80
83
90
OS
100
IDS
110
113
120
Antlmxy
( g/hr )
6.0E+01
6.8E+01
7.61*01
8.8E+01
9.6E+01
1.11*02
1.31+02
l.*I+02
1.8E+02
1 . 8E+02
2.0E+02
2.31*02
2.6E+02
3.0E+02
4.0E402
4.6E40J
6.01+02
7.BE402
9.6E+02
1.2E403
1.5E+03
1.7E+03
1.91403
2.21+09
2.3X409
2.8E+03
3.2E403
3.6E403
. Of 403
4.6E+03
3.4E403
6.0E403
Batlun
(K/hr)
1.01+04
1 . 1E+04
l.JE+04
1.4E+0*
1.7E+0*
1.8E404
2.11+0*
2.4E+04
2.7E+0*
3.0E+0*
3.*E+0
3.9E+0*
*.3E+0*
3.0E40*
6.8E40*
7.IE404
1.0E403
1.3E403
X.TE+03
2.0E405
2.SE40S
2.8E+03
3.2E40S
3.6E40S
.OE*03
4.8E403
3.*E*03
6.0E+03
8.8E40S
7.8E403
8.6X403
1.0S406
Ld
(/hr)
1.8E401
2.0E+01
2.3E401
 2.6E401
3.0E401
3.4E+01
3.6B+01
4.3E401
4.6E4Q1
3.4E401
6.0E+01
8.8E+01
7.8E+01
9.0E401
1.1E+02
1.4E402
1.8E+02
2.3E402
3.0E402
3.8E+02
4.3E402
3.0E402
3.8E402
6.41402
7.6E402
6.2Z402
9.6E402
1.U409
1.2E403
1.4E+03
1.6E403
1.8B+03
ttorciuy
(ji/hr)
8.0E+01
6.81+01
7.6E401
8.6E401
9.8E+01
1.1E+02
1.3E+02
1.41+02
l.SE+02
1.8E402
2.0E+02
2.3E402
2.8E+02
3.0E402
4.0E402
4.8E+02
6.0E+02
7.BE402
9.8E+02
1 2E+03
l.iE+03
1.7E+03
1.9E403
2 2E+03
2.3E409
2.6E403
3.2E-HJ3
9.6E403
4.0C403
4.6C403
3.4E403
6.0E409
Silvr
(/hr)
8.01+02
6. 81+02
7.6E+02
. 81+02
9.61+02
I. 11+03
1.3E+03
1.41+03
1.61+03
1.81+03
2.QE403
2.31+03
J. 81+03
3.01+03
4. Of 403
4. 61+03
6.01+03
7.8E403
9.6E403
1 2E+04
1.31+04
1.7E40*
1.91+04
2 2C4Q4
2.3E404
2.81+04
3. 2240*
3.6E+04
4.01+04
4.8E+04
3.4E404
6.0E404
Thalliua

6.0E+01
6.8E+01
7.6E+01
8.6E+01
9.6E+01
1 . 1E+02
1 . 31+02
1.4E+02
1.6E+02
1 . 8E+Q2
2.0E+02 .
2.3E+02
2.6E+02
3.0E+02
4.QE+02
4.61+02
6.0E+02
7.8E+02
9.8E+02
1.2E+03
1 . 3E+Q3
1.7E+03
1.9E+03
2.2E+03
2.SE+03
2.81+03
3.2E+03
3.6E+03
4.01+03
4.6E+03
3.41+03
8.0E+03

-------
       Appendix I.   Tier I and Tier II Feed Rate and Emissions
                Screening Limits for Hecals (Continued)

Table I-B.  TIER I AND TIER II FEED'RATE AND EMISSIONS SCREENING LIMITS
    FOR NONCARCINOGENIC METALS FOR FACILITIES IN NONCOMPLEX TERRAIN

Trtin Adju*t4
Eff. Stack Ht. ()
4
a

10
12
14
16
IB
20
22
2*
26
26
30
33
*0
AS
SO
33
60
69
TO
75
60
83
00
B3
100
103
110
115
120

Antimony
(t/ht)
3.11*01
3.6E*01
4.0E*01
4.61*01
3.8E*01
6.8E+01
8.8E*01
1.1*02
1.31*02
1.7E*02
2.21*02
2.81*02
3.51*02
4.31*02
7.21*0}
1.11*03
1.51*03
2.01*03
2.61*03
3.41*03
4. 61403
3.41*03
6.41*03
7.91*03
0.41*03
1 11*0*
1.3C*04
1.3E*04
1.61+44
2.2Z*0
2.6E*04
3.1t*0*
Vcluct fe
Berlin

3.2*03
6.01*03
B.6E+03
7.6Z*03
9.6E*03
1.12*04
1.4E-MJ*
l.BZ*04
2.2E*04
2.6Z*04
3.6E*04
4.61*04
3.8E+04
7.6C*04
1.21+03
i.ee*os
2.5C*OS
3.3E*03
4.4E*03
3.81*03
7.61*03
.OE*03
1.11*06
1.31*06
1.31*06
1 61*08
2.21*06
2.61*06
3.01*06
3.61*06
4.41*06
3.01*06
r Kuril Ar*t
U*d
(/ht)
9. 41*00
1.11*01
1.21*01
1.41*01
1.71*01
2.11*01
2.61*01
3.21*01
4.01*01
3.01*01
6.41*01
8.21*01
1.01*02
1.31*02
2.11*02
3.21*02
4.61*02
6.01*02
7.81*02
1.01*03
1.41*03
1.61*03
1.81*03
2.31*03
2.81*03
3 31*03
3.91*03
4.91*03
3.41*03
6.61*03
7.61*03
9.2K*03

Mecury
(/hr)
3.11*01
3.61*01
4.01*01
4.61*01
3.61*01
6.81*01
8.61*01
1.1E*02
1.3E*02
1.71*02
2.21*02
2.61*02
3.31*02
4.31*02
7.21*02
1.11*03
1.31*03
2.01*03
2.61*03
3.41*03
4.61*03
3.41*03
8.41*03
7.61*03
9.41*03
1.11*04
1.31*0*
1.51*04
1.81*0*
2.22*04
2.61*04
3.11*0*

SUvr
(/hr)
3 . 11*02
3.8E+02
4.0E+02
4.6E+02
3.8E+02
6.81*02
8.8E+02
1.1E+03
1.31*03
1.7E*03
2.21*03
2.81*03
3.31*03
4.3E*03
7.21*03
1.11*04
1.51*04
2.01*04
2.61*04
3.41*04
4.61*04
5.41*04
6.41*04
7.61*04
0.41*04
1.11*05
1.31*05
1.51*05
1.81*03
2.21*03
2.61*03
3.11*03

ThUiuo
(/hr>
3.1E+01
3.6E+01
*.OE+Ol
4.6E+OX
3 . 8E*01
6.6E01
8.6E+01
1.1E+02
1.31*02
Jl . 7E*02
J.2E+02 -
2.8E*02
3.3E+Q2
4.3E+02
7.2E*Q2
1.1E+03
l.SE+03
2.0E+03
2.61*03
3.4E*03
4.6E*03
3.41*03
6 . 4E+03
7.6E*Q3
9.4E+03
1.1E*04
1.31*04
1.31*04
1.81*04
2.21*04
2.61*04
3.11*04

-------
                      Appendix I.  - Tier I and Tier II Feed Race and Emissions
                               Screening Limits for Metals (Continued)               '

               Table  I-C.   TIER I AND TIER II FEED RATE AND EMISSIONS SCREENING LIMITS
                    FOR NONCARCINOGENIC METALS FOR  FACILITIES  IN COMPLEX TERRAIN
o

Trrin Adjuitwi
Itt. Stick Rt. (d)
*
6
8
10
12
It
IB
18
20
22
2*
26
28
30
33
to
45
SO
Si
60
63
70
73
80
85
90
95
100
10S
110
113
120

Antimony
U/hr)
1.4E+01
2.1E+01
3. OE+0 1
4.3E+01
5.4E+01
6.8E+01
7.8E+01
8.6E+01
9.81+01
1. OE+02
1 2E+02
1.3E+02
1 . 4E+02
1.6E+02
2 . OE+02
2 . 4E+02
3 . OE+02
3 . 8E+02
i.SE+02
3.8E+02
6.8Z+02
7.8E+02
8.6E+02
9.SE+02
1.1E+03
1.21*03
1.4E+03
1.31+03
1.7E+03
1. 92+49
2.1E+03
2.4E+03
Vlu foe Urban rod Kuril A
Baclw
(/hr)
2.*E+03
3 . SE+03
3.0E+03
7.6E*03
9.0E+03
1.1E+0*
1.3E+0*
l.*E+0*
l.SE+C*
l.JE+0*
1.9E+0*
2.2E+0*
2.4E+0*
2.7E+04
3 . 3E+0*
4.0E+0*
3 . OE+0*
6.0E+0*
7.81+04
B.4E+04
l.lE+flS
1.3E+OS
1 . 4E+05
1.6E-MJ3
1.8E+03
2.0E+OS
2. 31+03
2.6Z+03
2.8E+OS
3.2E+03
3.6E+03
4.0E+03
Ld
(/hr)
4.3E+00
6.2E+00
9.2E+00
1.3E+01
1.7E+01
2.0E+01
2.4E+01
2.6E+01
2.9E+01
3.2E+01
3.3E+01
3.6E+01
4.3E+01
4.6E+01
3.8E+01
7.2E+01
9.0E+01
1 . 1E+02
1.4E+02
1.7E+02
2. 11+02
2.4E+02
2.6E+02
2.91+02
3.3E+02
3.6E+02
4. OE+02
4.8E+02
5. OE+02
S.6E+02
6.4E+02
7.2Z+02
<
ttoreury
(/he)
1.4E+01
2.1E+01
3. OE+0 1
4.3E+01
3.4E+01
6.8E+01
7.8E+01
6.6E+01
9.6E+01
1. OE+02
1.2E+02
1.3E+02
1.4E+02
1.6E+02
2. OE+02
2.4E+02
3. OE+02
3.6E+02
4.6E+02
3.8E+02
6.BE+02
7.8E+02
8.8E+02
9.6E+02
1.1E+03
1 7K+03
1.4E+03
1.52+03
1.7E+03
1.9E+03
2.1E+03
2.4C+03

Silvir
(K/hr)
1.4E+02
2 . 1E+02
3 . OE+02
4 . 3E+02
S.4E+02
6.BE+02
7 . 8E+02
8.6E+Q2
9.6E+02
l.OE+03
1.2E+03
1.3E+03
1.4E+03
1.6E+03
2.0E+03
2.4E+03
3.0E+03
3.8E+03
4.8E+03
5.8E+03
6.8E+03
7.8E+03
8.6E+03
9.6E+03
1.1E+04
1 2E+4
1.4E+04
1.3E+04
1.7E+0*
1.9E+04
2.1E+04
2.4E+04

ThclUua
(t/hr)
1.4E+01
2.1E+01
3. OE+0 1
4.3E+01
5.4E+01
6.8E+01
7.8E+01
8.6E+01
9.6E+01
1. OE+02
1.2E+02
1.3E+02
1.4E+02
1.6E+02
2. OE+02
2.4E+02
3 . OE+02
3.6E+02 '
4.6E+02
S.8E+02
6.8E+02
7.8E+02
8.6E+02
9.6E+02
1 . 1E+03
1.2E+03
1.4E+03
1.3E+03
1.7E+03
1.9E+Q3
2.1E+03
2.4E+03

-------
       Appendix I.   - Tier I and Tier II Feed Race and Emissions
                Screening Limits for Metals (Continued)

Table I-D.  TIER I AND TIER II FEED RATE AND EMISSIONS SCREENING LIMITS
    FOR NONCARCINOGENIC METALS FOR FACILITIES IN NONCOMPLEX TERRAIN

Ttrrun
Adjusted
.
Stack Ht.
(HI)
4
8
8
10
12
14
16
18
20
22
2*
26
28
30
39
40
45
SO
33
BO
63
70
73
80
83
90
93
100
103
110
113
120
Vtluvs for <] in Utbn ATMS
Antc

1.72-0.1
1.9E-01
2.22-01
2.4E-01
2.72-01
3 . 12-01
3.SI-01
4.0C-01
4.4E-01
t 01-01
3.8E-01
6.4E-01
7.22-01
8.22-01
1.02*00
1.32*00
1.72*00
2.22*00
2.71*00
3.42*00
4.22*00
4.62*00
3.42*00
6.01*00
6.82*00
7.82*00
0.02*00
1.02*01
1.12*01
1.32*01
1.92*01
1.72*01
Vlu Cot !) in
Barrllita
t/hr)
8.22-01
9.4E-01
1.12*00
1.22*00
1.42*00
1.32*00
1.7E*00
2.02*00
2.22*00
2 3E*00
2.82*00
3.22*00
3.62*00
4.02*00
3.42*00
6.82*00
8.62*00
1.^2*01
1.42*01
1.72*01
2.12*01
2.42*01
2.72*01
3.02*01
3.42*01
3.92*01
4.42*01
3.02*01
3.62*01
6.42*01
7.22*01
8.22+01
Arsmie
(8/hc)
2.4E-01
2.82-01
3.22-01
3.62-01
4.32-01
3.4E-01
6.82-01
6.22-01
1.02*00
1 32*00
1.72*00
2.12*00
2.72*00
3.32*00
3.42*00
8.22*00
1.12*01
1.32*01
2.02*01
2.72*01
3.62*01
4.32*01
3.02*01
6.02*01
7.22*01
8.62*01
1.02*02
1.22*02
1.42*02
1.72*02
J. 02*02
2.42*02
lux*! ATOM
Ckdoim
(/he)
3.62-01
6.62-01
7.82-01
8.62-01
1.1E*00
1.32*00
1.82*00
2.02*00
2.32*00
3 22*00
4.02*00
3.02*00
6.42*00
8.22*00
1.32*01
2.02*01
2.82*01
3.72*01
3.02*01
8.42*01
8.82*01
1.02*02
1.22*02
1.42*02
1.72*02
2.02*02
2.42*02
2.92*02
3.42*02
4.02*02
4.82*02
3.82+02

ChromluB

8.62-02
l.OE-01
1.12-01
1.32-01
1.62-01
2.02-01
2.42-01
3.0E-01
3.72-01
4.82-01
6.02-01
7.62-01
9.62-01
1.22*00
1.92*00
3.02*00
4.22*00
3.42*00
7.22*00
9.62*00
1.32*01
1.32*01
1.82*01
2.22*01
2.62*01
3.02*01
3.62*01
4.32*01
3.02*01
6.02*01
7.22*01
6.62*01
8rylUua
(/ht)
* 3E-01
S.Ot-01
5.6E-01
6.4E-01
7.8E-01
9.62-01
1 . 2E+00
1.32*00
1.91*00
2.4E*00
3.02*00
3.91*00 .
5.0E*00-
6.22*00
9.8E+00
1.32*01
2.12*01
2.82*01
3.62*01
4.82*01
6.42*01
7.62*01
9.02*01
1.12*02
1.32*02
1.32*02
1.82*02
2.22*02
2.62*02
3.02*02
3,62*02
4.32*02

-------

       Appendix I.   -  Tier I and Tier II Feed Race and  Emissions        '
                 Screening Limits for Metals (Continued)

Table I-E.  TIER I  AND TIER II FEED RATE AND EMISSIONS  SCREENING LIMITS
       FOR CARCINOGENIC METALS FOR FACILITIES IN  COMPLEX TERRAIN


                           for tit* in Urbui 4Uld Rural ACM
T.rraiB Adjusted Eft.
Stack Kt. (a)
4
6
6
10
12
14
18
18
20
22
2*
26
28
30
35
*0
45
so
55
80
83
70
75
80
8S
90
95
100
109
110
113
120
Arimie
(t/hr)
1.1E-01
1.61-01
2.4E-01
3.JE-01
*.3-01
S.OE-01
6.0E-01
8.8E-01
7.82-01
8.2E-01
9.0E-01
l.OE+00
1.1E+00
1.2E+00
1 . SE+00
1.9E+00
2.4E+00
2.9E+00
3.5E+00
4.31+00
5 . 4E+00
6.0E*00
8.8E+00
7.BE400
8.2E+00
Q.4E+00
1.01+01
1.2E*fll
1.3E*01
1.5EWJ1
1.7E+01
1.9E-HJ1
Cactmiw
t/hr)
2.8E-01
3.9E-01
5.8E-01
8.2E-01
l.OE+00
1.3E+00
1.4C+00
1.6E+00
1.8E*00
1.9E*00
2.1E+00
2.4E+00
2.7E-HJO
3.0E-MJO
J.7E*00
*.6E+00
S.4E+00
e.n*oo
8.*E*00
l.OE+01
1.3E+01
l.*E*01
1.8E+fll
1.8E*fll
2.0E*01
' 2.3E+O1
2.SE*01
2.8E1
3.2E-MJ1
3.5E401
4.0E+01
*.E*01
Chveoian
(/hrl
*.OE-02
S.8E-02
6.6E-02
1.3E-01
1.5E-01
1.8E-01
2.2E-01
2.4E-01
2.7E-01
3.0E-01
3.3E-01
3.6E-01
4.0E-01
4.4E-01
S.4E-01
6.SE-01
8.4E-01
l.OE+00
1.3E*00
1.5E-MJO
1.9E*00
2.2E*00
2.4E*0
2.7E*0
3.0E-MJO
3.4E*00
4.0E-K)0
4.3E-HJO
4.8E-HJO
5.*00
6.0E-HIO
8.4E-HJO
BIT Uium
2 OE-01
2 9E-01
4 3E-01
6.2E-01
7.6E-01
9.4E-01
1.1E*00
1.2E+00
1.31+00
1.5E+00
1.6E+00
1.8E+00
2 . OE+00
2.2E+00
2.7E+00
3.4E+00
4.2E*00
3.0E*00
6.4E+00
7.8E+00
9.6E+00
1.1E+01
1.2E01
1.3E*01
1.5E+01
1.7E*01
1.9E+01
2.1E+01
2.41+01
2.7E*01
3.0E+01
3.3E+01

-------
Appendix II. ' Tier I  Feed Race Screening Limics for Total Chlorine and Chloride
                  TIER I FEED RATE SCREENING LIMITS FOR CHLORINE FOR FACILITIES
                             NONCOMPLEX AND COMPLEX TERRAIN
Terrain- adjuated
effective stack
height (a)
4
6
8
10
12
14
16
18
20
22
24
26
28
30
35
40
45
50
S3
60
65
70
75
80
85
90
93
100
105
110
115
120
None OOP lax
Urban
ab/hr)
1.8E-02
2.0E-02
2.2E-02
2.5E-02
2.9E-02
3.3E-02
3.7E-02
4.1E-02
4.7E-02
5.3E-02
6.0E-02
6.8E-02
7.6E-02
8.7E-02
1.2E-01
1.4E-01
1.8E-01
2.3E-01
2.9E-01
3.6E-01
4.3E-01
5.0E-01
S.6E-01
6.3E-01
7.3E-01
8.3E--1
9.3E-01
1.1E+00
1.2E+00
l.4E*00
1.6E+00
1.8E+00
Rural
(Ib/hr)
9.2E-03
l.OE-02
1.2E-02
1.4E-02
1.7E-02
2.0E-02
2.5E-02
3.2E-02
3.9E-02
5.0E-02
6.3E-02
8.1E-02
l.OE-01
1.3E-01
2.1E-01
3.2E-01
4.4E-01
S.8E-01
7.7E-01
l.OE+00
1.4E-M)0
1.6E+00
1.9E*00
2.2E+00
2.8E+00
3.2E+00
3.8E+00
4.6E+00
5.4E+00
6.5E+00
7.7E+00
9.1E+00
Complex
(Ib/hr)
4.1E-03
6.1E-03
9.0E-03
1.3E-02
1.6E-02
2.0E-02
2.3E-02
2.5E-02
2.9E-02
3 . 1E-02
3.5E-02
3.8E-02
4.2E-02
4.7E-02
S.8E-02
7.2E-02
8.8E-02
1.1E-01
1.4E-01
1.7E-01
2.0E-01
2.3E-01
2.5E-01
2.9E-01
3.2E-01
3.6E-01
4.0E-01
4.4E-01
5.0E-01
5.6E-01
6.2E-01
7.1E-01

-------
Appendix III.  . Tier  II  Emission Rate Screening Limits for Free Chlorine
                Hydrogen Chloride
             TIER II EMISSIONS SCREENING LIMITS FOR Cl, AND HC1 IN NONCOKPLEX TERRAIN
Terrain- adjusted
effective stack
height (a)
4
6
8
10
12
14
16
18
20
22
24
26
28
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
Values for use
In urban area*
Cl,
(E/iec)
2.3E-03
2.5E-03
2.8E-03
3.2E-03
3.6E-03
4. IE- 03
4.7E-03
5.2E-03
5.9E-03
6.7E-03
7.6E-03
8.5E-03
9.6E-03
1.1E-02
1.5E-02
1.7E-02
2.3E-02
2.9E-02
3.6E-02
4.5E-02
5.5E-02
6.3E-02
7.1E-02
8.0E-02
9.2E-02
l.OE-01
1.2E-01
1.3E-01
1.5E-01
1.7E-01
2.0E-01
2.3E-01
HC1
(/sec>
4.0E-01
4.4E-01
4.9E-01
5.6E-01
6.3E-01
7.2E-01
8.2E-01
9.1E-01
l.OE+00
1.2E-K)0
1.3E+00
1.5E*00
l.7E*00
1.9E*00
2.6E4OO
3.0E+00
4.0E+00
5.1E-HOO
6.3E+OO
7.9E+00
9.6E+00
1.1E-MD1
1.2E+01
1.4E-K01
1.6E+01
1.8E+01
2.1E+01
2.3E-KI1
2.6E-M31
3.0E-HJ1
3.SE+01
4.0E401
Values for use
in rural areas
Cl,
(K/sec)
1.2E-03
1.3E-03
1.5E-03
1.7E-03
2.1E-03
2.5E-03
3.2E-03
4.0E-03
4.9E-03
6.3E-03
8.0E-03
l.OE-02
1.3E-02
1.6E-02
2.7E-02
4.0E-02
5.6E-02
7.3E-02
9.7E-02
1.3E-01
1.7E-01
2.0E-01
2.4E-01
2.8E-01
3.5E-01
4.0E-01
4.8E-01
5.7E-01
6.8E-01
8.1E-01
9.7E-01
1.1E+00
HC1
(K/sec)
2.0E-01
2.3E-01
2.6E-01
3.0E-01 '
3.7E-01
4.4E-01
5.6E-01
7.0E-01
8.6E-01
1 . IE+00
1.4E+00
1.8E+00
2.3E+00
2 . 8E+00
4 . 7E+00
7.0E+00
9.8E-M30
V. 3E*Ol
1.7E+01
2.2E-M)!
3.0E*01
3 . 5E+ 01
4.2E4-01
4.9E*Ol
6.1E+OL
7.0E+01
8.4E*01
1.0E-K)2
1.2E*02
1.4E^02
1.7E+02
2.0E+02

-------
Appendix III'. (Continued)
            TIER  II  EMISSIONS SCREENING LIMITS FOR Cl, AND HC1 IN COMPLEX TERRAIN
Terrain- adj us tad
effective stack
height (m)




























,



4
6
8
10
12
14
16
18
20
22
24
26
28
30
35
40
45
SO
ss
60
65
70
75
80
85
90
95
100
105
110
115
120
Value* for use in urban
and rural area*
Cl,
(c/sec)
5.2E-04
7.7E-04
1.1E-03
1.6E-03
2.0E-03
2.5E-03
2.9E-03
3.2E-03
3.6E-03
3.9E-03
4.4E-03
4.8E-03
5.3E-03
S.9E-03
7.3E-03
9.1E-03
1.1E-02
1.3E-02
1.7E-02
2. IE -02
2.5E-02
2.9E-02
3.2E-02
3.6E-02
4.0E-02
4.SE-02
5.1E-02
5. 61- 02
6.3E-02
7.1B-02
7.91-02
8.9E-02
HC1
(2/ee)
9.1E-02
1.4E-01
2.0E-01
2.8E-01
3.5E-01
4.4E-01
.1E-01
.6E-01
.3E-01
.8E-01
.7E-01
.4E-01
.3E-01
l.OE+00
1.3E-M)0
1.6E+00
1.9E-IOO
2.3E100
3.0E+00
3.7E+00
4.4E+00
5.1E*00
5.6E-HOO
6.3E+00
7.0E-M30
7.9E+00
8.9E+00
9.8E+00
1.1E+01
1.2E*01
1.4E+01
1.6E+01

-------
           Appendix IV.  - Reference Air Concentration!*
O
Constituent c
Acetaldehyde 	
Acetonitrile 	
Acetophenone 	
Acrolein 	
Aldicarb 	
Aluminum Phosphide 	
Ally! Alcohol 	
Antimony 	 	 	
Barium 	
Barium Cyanide ...........
Bromome thane 	
Calcium Cyanide 	
Carbon Disulfide 	
Chloral 	
Chlorine (free) 	 	
2 -Chloro- 1,3 -butadiene. . .
Chromium III 	
Copper Cyanide 	
Cresols 	
Cumene 	
Cyanide (free) 	
Cyanogen 	
Cyanogen Bromide 	
Di-n- butyl Phthalate 	
o - Dichlorobenzene 	
p-Dichlorobenzene 	
Dichlorodif luorome thane . .
2,4-Dichlorophenol 	
Die thy 1 Phthalate 	
Dimethoate 	
2 , 4-Dinitrophenol 	
Dinoseb 	
Diphenylamine 	
Endosulfan 	
Endrin 	
Fluorine 	 	
Formic Acid 	
Glycidyaldehyde 	
Hexachlorocyclopentadiene
Hexachlorophene 	 	
Hydrocyanic Acid 	
Hydrogen Chloride. 	 	
Hydrogen Sulfide 	
Isobutyl Alcohol 	
Lead 	
Maleic Anyhdride 	
Mercury 	 	 	
Methacrylonitrile 	
AS No. RA
75-07-0
75-05-8
98-86-2
107-02-8
116-06-3
20859-73-8
107-18-6
7440-36-0
7440-39-3
542-62-1
74-83-9
592-01-8
75-15-0
75-87-6

126-99-8
16065-83-1
544-92-3
1319-77-3
98-82-8
57-12-15
460-19-5
506-68-3
84-74-2
95-50-1
106-46-7
75-71-8
120-83-2
84-66-2
60-51-5
51,- 28 -5
88-85-7
122-39-4
115-29-7
72-20-8
7782-41-4
64-18-6
765-34-4
77-47-4
70-30-4
74-90-8
7647-01-1
7783-06-4
78-83-1
7439-92-1
108-31-6
7439-97-6
126-98-7
>C (ug/m3)
10
10
100
20
1
0.3
5
0.3
50
50
0.8
30
200
2
0.4
3
1000
5
50-
1
20
30
80
100
10
10
200
3
800
0.8
2
0.9
20
0.05
0.3
50
2000
0.3
5
0.3
20
7
3
300
0.09
100
0.3
0.1

-------
Appendix XV.  (Continued)
Constituent             CAS No.     RAC '(ug/m5)

Methomyl	16752-77-5        20
Methoxychlor	   72-43-5        50
Methyl Chlorocarbonate...   79-22-1      1000
Methyl Ethyl Ketone	   78-93-3        80
Methyl Parathion	  298-00-0       0.3
Nickel Cyanide	  557-19-7        20
Nitric Oxide	10102-43-9       100
Nitrobenzene	   98-95-3       0.8
Pentachlorobenzene	  608-93-5       0.8
Pentachlorophenol	   87-86-5        30
Phenol	  108-95-2        30

Phenylmercurie Acetate...   62-38-4     0.075
Phosphine..	 7803-51-2       0.3
Phchalic Anhydride	   85-44-9      2000
Potassium Cyanide	  151-50*8        50
Potassium Silver Cyanide.  506-61-6       200
Pyridlne	  110-86-1         I
Selenious Acid	 7783-60-8         3
Selenourea	  630-10-4         5
Silver	 7440-22-4         3
Silver Cyanide	  506-64-9       100
Sodium Cyanide	  143-33-9        30
Strychnine	   57-24-9       0.3
1,2,4,5-Tetrachlorobenzene  95-94-3       0.3
2,3,4,6-Tetrachlorophenol   58-90-2        30
Tetraethyl Uad	   78-00-2    0.0001
Tetrahydrofuran	  109-99-9        10
Thai lie Oxide	 1314*32*5       0.3
Thallium	 7440-28*0       0.5
Thallium (1) Acetate	  563-68-8       0.5
Thallium (I) Carbonate... 6533-73-9       0.3
Thallium (I) Chloride	7791-12-0       0.3
Thallium (I) Nitrate	10102-45-1       0.5
Thallium Selenice	12039*52-0       0.5
Thallium (I) Sulfate	 7446-18-6     0.075
Thiram	  137-26*8         5
Toluene	  108-88*3       300
1,2,4-Trichlorobenzene...  120-82-1        20
Trichloromonofluoromethane  75-69-4       300
2,4,5-Trichlorophenol....   95*95-4       100
Vanadium Pentoxide	 1314*62-1        20
Warfarin	   81-81-2       0.3
Xylenes	 1330-20-7        80
Zinc Cyanide	  557-21-1        50
Zinc Phosphide	 1314-84*7       0.3

*     The RAC for other Appendix VIII Part 261 constituents not listed hereint
      or in Appendix 4. of this  Part  is 0.09 ug/m1.

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          Appendix V. - Risk Specific  Doaes  (10**)
o
Conscicuenc

Acrylonicrile 	
ALdrin 	
Aniline 	
Arsenic 	
Benz (a) anthracene . .....
Benxene 	
Benzidine 	 	
Benzo(a)pyrene 	 	
Beryllium 	 	
Bis(2-chloroethyl)ether
Bis (chloromethyl) ether.
Bis(2-ethylhexyl)-
phthalate 	
13- Butadiene 	
Cadmium 	
Carbon Tetrachloride. . .
Chlordane 	
Chloroform 	
Chlorome thane 	
Chromium VI 	
DDT 	
D ibenz ( a , h ) anthracene . .
l,2-Dtbromo-3-
chloropropane 	
1 2 - Dibroinoehtane 	
1 1-Dichloroe thane 	
1 2-Dichloroethane 	
1, 1-Dichloroe thylene. . .
1 , 3-Dichloropropene. . . .
Dieldrin 	
Diethylstilbestrol 	
Dime thy Initrosamine. . . .
2 4 -Dinitro toluene 	
1 , 2 -Diphenylhydrazine . .
1 4-Dioxane 	
Epichlorohydrin 	
Ethylene Oxide 	 	
Ethylene Dibrotnide
Formaldehyde 	
Heptachlor 	
Heptachlor Eposide 	
Hexachlorobenzene 	
Hexachlorobutadiene ....
CAS No.
79-06-1
107-13-1
309-00-2
62-53-3
7440-38-2
56-55-3
71-43-2
92-87-5
50-32-8
7440-41-7
111-44-4
542-88-1
117-81-7
106-99-0
7440-43-9
56-23-5
57-74-9
67-66-3
74-87-3
7440-47-3
50-29-3
53-70-3
96-12-8
106-93-4
75-34-3
107-06-2
75-35-4
542-75-6
60-57-1
56-53-1
62-75-9
121-14-2
122-66-7
123-91-1
106-89-8
75-21-8
106-93-4
50-00-0
76-44-8
1024-57-3
118-74-1
87-68-3
Unit risk
(m3/ug)
1 3E-03
6.8E-05
4.9E-03
7.4E-06
4.3E-03
8.9E-04
8.3E-06
6.7E-02
3.3E-03
2.4E-03
3.3E-04
6.2E-02
2.4E-07
2.8E-04
1.8E-03
1.5E-05
3.7E-04
2.3E-05
3.6E-06
1.2E-02
9.7E-05
1.4E-02
6.3E-03
2.2E-04
2.6E-05
2.6E-05
5.0E-05
3.5E-01
4.6E-03
1.4E-01
1.4E-02
8.8E-05
2.2E-04
1.4E-06
1.2E-06
l.OE-04
2.2E-04
1.3E-05
1.3E-03
2.6E-03
4.9E-04
2.0E-05
RsD
(ug/m3)
7 7E-03
1.5E-01
2.0E-03
1 . 4E+00
2.3E-03
1.1E-02
1 . 2E+00
1.5E-04
3.0E-03
4.2E-03
3.0E-02
1.6E-04
4.2E+01
3.6E-02
5.6E-03
6.7E-01
2.7E-02
4.3E-01
2 . 8E+00
8.3E-04
l.OE-01
7.1E-04
1.6E-03
4.5E-02
3.8E-01
3.8E-01
2.0E-01
2.9E-05
2.2E-03
7.1E-05
7.1E-04
1.1E-01
4.5E-02
7 . 1E+00
8.3E+00
l.OE-01
4.5E-02
7.7E-01
7.7E-03
3.8E-03
2.0E-02
5.0E-01

-------
Appendix V. (Continued)
Constituent
Alpha -hexachloro -
cyclohexane 	
Beta-hexachloro-
cyclohexane 	
Gamma -hexachloro -
eye lohexane 	 	 	
Hexaehlorocyclo-
hexane, Technical.
Hexachlorodibcnxo -p-
dioxln(l,2 Mixture)
Hexachlor oe thane . 	 	
Hydraz ine 	
Hydrazine Sulfate 	
3-Methylcholanthrene. . .
Methyl Hydrazine 	
Methylene Chloride ... .
4,4'-Methylene-bis-2-
chloroaniline 	
Nickel 	
Nickel Refinery Dust...
Nickel Subsulf ide 	
2-Nitropropane 	
N-Nitroso-n-butylamine .
N-Nitroso-n-methylurea.
N-Nitrosodiethylaaine. .
N-Nicrosopyrrolidine. . .
Pencachloronitrobenzene
PCBs 	 	
Pronamide ..............
Reserpine 	 	
2,3,7 , 8-Tetrachloro-
dibnzo-p-dioxin. .
1,1,2.2 -Tetrachloroe thane
Tetrachloroethylene ....
Thiourea 	 	
1,1,2 -Trichloroe thane . .
2,4,6 -Tr ichlorophenol . .
Vinvl Chloride 	
CAS No.
319-84-6
319-85-7
58-89-9
67-72-1
302-01-2
302-01-2
56-49-5
60-34-4
75-09-2
101-14-4
7440-02-0
7440-02-0
12035-72-2
79-46*9
924-16-3
684-93-5
55-18-5
930-55-2
82-68-8
1336-36-3
23950*58-5
50-55-5
1746-01-6
79-34-5
127-18-4
62-56-6
79-00-5
79-01-6
88-06-2
8001-35-2
75-01-4
Unit risk
(m3/ug)
1 8E-03
5.3E-04
3.8E-04
5.1E-04
1.3E+00
4.0E-06
2.9E-03
2.9E-03
2.7E-03
3.1E-04
4.1E-06
4.7E-05
2.4E-04
2.4E-04
4.8E-04
2.7E-02
1.6E-03
8.6E-02
4.3E-02
6.1E-04
7.3E-OS
1.2E-03
4.6E-06
3.0E-03
4.SE+01
5.8E-05
4.8E-07
5.5E-04
1.6E-05
1.3E-06
5.7E-06
3.2E-04
7.1E-06
RsD
(ug/m3)
5 6E.03
1.9E-02
2.6E-02
2.0E-02
7.7E-06
2.5E+00
3.4E-03
3.4E-03
3.7E-03
3.2E-02
2.4E+00
2.1E-01
4.2E-02
4.2E-02
2.1E-02
3.7E-04
6.3E-03
1.2E-04
2.3E-04
1.6E-02
1.4E-01
8.3E-03
2 . 2E+00
3.3E-03
2.2E-07
1.7E-01
2.1E+01
1.8E-02
6.3E-01
7 . 7E+00
1.8E-MDO
3. IE- 02
1.4E+00

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                    Appendix VI.  -  Stack  Plume Rise
                        s
                        H

                        V)



                        a
                        Id
                        S
                        V)
                        s
     O
                        M
                        
                        i



                                                                                        
                                                                                      __ _
                                                                                      *nr.i
                                                                                      ^priffrf*^^
                                                                                       I  I   l l 0k
                                                                                              --A

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Appendix VII. - Health-Based Limits for Exclusion of Waste-Derived Residues*
Metals - TCLP Extract Concentration Limits

Constituent
Antimony
Arsenic
Barium
Beryllium
Cadmium
Chromium
Lead
Mercury
Nickel
Selenium
Silver


CA.S No.
7440-36-0
7440-38-2
7440-39-3
7440-41-7
7440-43-9
7440-47-3
7439-92-1
7439-97-6
7440-02-0
7782-49-2
7440-22-4
Nonmetals
Concentration
Limits (mf/kg^
IxE+OO
SxE+00
lxE+02
7xE-03
IxE+OO
5xE+00
5xE+00
2xE-01
7xE+01
IxE+OO
SxE-t-00
- Residue Concentration Limits
Constituent

Acetonitrile
Acetophenone
Acrolein
Acrylaiside
Acrylonicrile
Aldrin
Allyl alcohol
Aluminum phosphide
Aniline
Barium cyanide
Benz(a)anthracene
Benzene
Benzidine
Bis(2-chloroethyl) ether
Bis(chloromethyl) ether
Bis(2-ethylhexyl) phthalate
Bromoform
Calcium cyanide
Carbon disulfide
Carbon tetrachloride
Chlordane
Chlorobenzene
Chloroform
Copper cyanide
Cresols (Cresylic acid)
CAS Ho.

75-05-8
98-86-2
107-02-8
79-06-1
107-13-1
309-00-2
107-18-6
20859-73-8
62-53-3
542-62-1
56-55-3
71-43-2
92-87-5
Ul-44-4
542-88-1
117-81-7
75-25-2
592-01-8
75-15-0
56-23-5
57-74-9
108-90-7
67-66-3
S44-92-3
1319-77-3
Concentration
Limits for
Residues (my/kg*)

2xE-01
4xE+00
5xE-01
2xE-04
7xE-04
2xE-05
2xE-01
lxE-02
6xE-02
IxE+OO
lxE-04
5XE-03
lxE-06
3xE-04
2xE-06
3xE+01
7xE-01
lxE-06
4xE+00
SxE-03
3xE-04
IxE+OO
6xE-02
2xE-01
2xE+00

-------
Appenidix VII.(Continued)
                   Nonaecals  - Residue Concentration Limits
Constituent                         CAS No.

Cyanogen                            460-19-5
DDT                                 50-29-3
Dlbenz(a,h)anthracene               53-70-3
1.2 -Dibromo- 3 -chloropropane         96-12-8
p-Dichlorobenzene                   106-46-7
Dichlorodifluoromethane             75-71-8
1,1-Dichloroethylene                75-35-4
2,4-Dichlorophenol                  120-83-2
1,3-Dichloropropene                 542-75-6
Dieldrin                            60-57-1
Diechyl phthalate                   84-66-2
Diethylstilbesterol                 56-53-1
Dimethoate                          60-51-5
2,4-Dinitrotoluene                  121-14-2
Diphenylamine                       122-39-4
1.2-Diphenylhydrazine               122-66-7
Endosulfan                          115-29-7
Endrin                              72-20-8
Epichlorohydrin                     106-89-8
Echylene dibromide                  106-93-4
Ethylene oxide                      75-21-8
Fluorine                            7782-41-4
Formic acid                         64-18-6
Heptachlor                          76-44-8
Heptachlor epoxide                  1024.57-3
Hexachlorobenzene                   118-74-1
Hexachlorobutadiene                 87-68-3
Hexachlorocyclopentadiene           77-47-4
Hexachlorodibenzo-p-dioxins         19408-74-3
Hexachloroethane                    67-72-1
Hydrazine                           302-01-1
Hydrogen cyanide                    74-90*8
Hydrogen sulfide                    7783-06-4
Isobutyl alcohol                    78-83-1
Methomyl       .                     16752-77-5
Methoxychlor    ,                    72-43-5
3-Methylcholanchrene                56-49-5
4.4'-Methylenebis(2-chloroaniline)  101-14-4
Methylene chloride                  75-09-2
Methyl ethyl ketone (MEK)           78-93-3
Methyl hydrazine                    60-34-4
Methyl parathion                    298-00-0
Naphthalene                         91-20-3
Nickel cyanide                      557-19-7
Nitric oxide                        10102-43-9
Nitrobenzene                        98-95-3
Concentration
Limits for
Residues
IxE+OO
lxE-03
7xE-06
2xE-05
7.5xE-02
7xE+00
5xE-03
lxE-01
lxE-03
2xE-05
3xE+01
7xE-07
3xE-02
5xE-04
9xE-01
5xE-04
2xE-03
2xE-04
4xE-02
4xE-07
3xE-04
4xE+00
7xE+01
8xE-05
4xE-05
2xE-04
5xE-03
2xE-01
6xE-08
3xE-02
lxE-04
7xE-05
lxE-06
lxEi-01
IxE+OO
lxE-01
4xE-05
2xE-03
5xE-02
2xE+00
3xE-04
2xE-02
7xE-01
4xE+00
2xE-02

-------
Appendix VII. (Continued)
Nonmetals - Residue Concentration Limits

done r i cuent
N-Nitrosodi-n-butylamine
N-Nitrosodiethylamine
N-Nitroso-N-methylurea
N-Nitrosopyrrolidine
Pentachlorobenzene
Pentachloronitrobenzene (PCNB)
Pentachlorophenol
Phenol
Phenylmercury acetate
Phosphine
Polychlorinated biphenyls, N.O.S.
Potass i-.:r cyanide
Potass i silver cyanide
Pronami
Pyridin.
Reserpi
Selenou. a
Silver cyanide
Sodium cyanide
Strychnine
1 , 2 ,4 , 5-Tetrachlorobenzene
1,1,2,2- tetrachloroe thane
Tetrachloroethylene
2,3,4, 6 -Tetrachlorophenol
Tetraethyl lead
Thallium
Thai lie oxide
Thallium(I) acetate
ThalUum(I) carbonate
Thai. .jm(I) chloride
Thai . -and) nitrate
Thal.:um selenite
ThalLium(I) sulfate
Thiourea
Toluene
Toxaphene
1,1,2 -Trlchloroe thane
Trichloroethylene

CAS No.
924-16-3
55-18-5
684-93-5
930-55-2
608-93-5
82-68-8
87-86-5
108-95-2
62-38-4
7803-51-2
1336-36-3
151-50-8
506-61-6
23950-58-5
110-86-1
50-55-5
630-10-4
506-64-9
143-33-9
57-24-9
95-94-3
79-34-5
127-18-4
58-90-2
78-00-2
7440-28-0
1314-32-5
563-68-8
6533-73-9
7791-12-0
10102-45-1
12039-52-0
7446-18-6
62-56-6
108-88-3
8001-35-2
79-00-5
79-01-6
Limits for
Residues (me/kE)
6xE-05
2xE-06
lxE-07
2xE-04
3xE-02
lxE-01
IxE+OO
IxE+OO
3xE-03
lxE-02
5xE-05
2xE+00
7xE+00
3xE+00
4xE-02
3xE-05
2xE-01
4xE+00
IxE+OO
lxE-02
lxE-02
2xE-03
7xE-01
lxE-02
4xE-06
7xE+00
2xE-03
3xE-03
3xE-03
3xE-03
3xE-03
3xE-03
3xE-03
2xE-04
lxE+01
5xE-03
6xE-03
5xE-03

-------
Appendix VIZ. (Continued)
                   Nonmetals - Residue Concentration Limits
Constituent

Trichloromonofluoromethane
2,4,5-Trichlorophenol
2,4,6-Trichlorophenol
Vanadium pentoxide
Vinyl chloride
CAS No.

75-69-4
95-95-4
88-06-2
1314-62-1
75-01-4
Concentration
Limits for
ResiduesCmg/kg>

lxE+01
4xE+00
4xE+00
7xE-01
2XE-03
      The  health-based  concentration  limits   for   Appendix  vm  Fart  261
      constituents for which a health-based concentration is not provided below
      is 2xE-06 mg/kg.

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Appendix VIZI. - Potential PICs  for Determination of Exclusion of Waste-Derived
                 Residues
               PICs FOUND IN STACK EFFLUENTS

         Volatiles   :            Semivolatiles
   Benzene
   Toluene
   Carbon tetrachloride
   Chloroform
   Methylene chloride
   Trichloroethylene
   Tetrachloroethylene
   1,1.1-Trichloroethane
   Chlorobenzene
   cis-1.4-Dichloro-2-bucene
   Bromochloromethane
   Bromodichloromethane
   Bromofonn
   Bromomethane
   Methylene bromide
   He thy1 ethyl ketone
Bis(2-ethylhexy1)phthalate
Naphthalene
Phenol
Diethy1 phthalate
Butyl benzyl phthalate
2,4-Dimethylphenol
o-D ichlorobenzene
m-Dichlorobenzene
p-Dichlorobenzene
Hexachlorobenzene
2.4,6-Trichlorophenol
Fluoranthene
o-Nitrophenol
1,2,4-trichlorobenzene
o-Chlorophenol
Pentachlorophenol
Pyrene
Dimethyl phthalate
Mononitrobenzene
2,6-Toluene diisocyanate

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