NOTE: This document shows new language changes resulting from OMB review
Iin RED), and new language changes made by EPA in BLUE)

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 261

[EPA-HQ-RCRA-2005-0017; FRL -              ]

RIN  2050-AG24

Expansion of RCRA Comparable Fuel Exclusion

AGENCY:  Environmental Protection Agency (EPA).

ACTION:  Proposed rule.

------------------------------------------------------------------------
---------------------------------

SUMMARY:  :  EPA is proposing to expand the comparable fuel exclusion
under section 261.38 of the rules implementing subtitle C of the
Resource Conservation and Recovery Act (RCRA) for fuels that are
produced from hazardous waste but which generate emissions that are
comparable to emissions from burning fuel oil when such fuels are burned
in an industrial boiler.  Such excluded fuel would be called
emission-comparable fuel (ECF).  ECF would be subject to the same
specifications that currently apply to comparable fuels, except that the
specifications for certain hydrocarbons and oxygenates would not apply.
The ECF exclusion would be conditioned on requirements including:  (1)
design and operating conditions for the ECF boiler to ensure that the
ECF is burned under the good combustion conditions typical for oil-fired
industrial boilers; and (2) conditions for tanks storing ECF which
conditions are typical of those for storage of commercial fuels, and are
tailored for the hazards that ECF may pose.

DATES:  Comments must be received on or before [INSERT DATE 60 DAYS
AFTER  PUBLICATION IN THE FEDERAL REGISTER].  Under the Paperwork
Reduction Act, comments on the information collection provisions must be
received by OMB on or before [insert date thirty days after date of
publication in the Federal Register.]

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      ●	  HYPERLINK "http://www.regulations.gov"  www.regulations.gov
:  Follow the on-line instructions for submitting comments.

Email:   HYPERLINK<EMAIL_ADDRESS><EMAIL_ADDRESS>.

Fax:<PHONE_NUMBER>.

Mail: RCRA Docket, Environmental Protection Agency, Mailcode: 2822T,
1200 Pennsylvania Ave., NW., Washington, DC 20460.  Please include a
total of two copies.  We request that you also send a separate copy of
your comments to the contact person listed below (see FOR FURTHER
INFORMATION CONTACT). In addition, please mail a copy of your comments
on the information collection provisions to the Office of Information
and Regulatory Affairs, Office of Management and Budget (OMB), Attn:
Desk Officer for EPA, 725 17th St. NW., Washington, DC 20503.

Hand Delivery:  RCRA Docket, EPA Docket Center (2822T), EPA West, Room
3334, 1301 Constitution Ave., NW., Washington, DC.  Such deliveries are
only accepted during the Docket’s normal hours of operation, and
special arrangements should be made for deliveries of boxed information.
 Please include a total of two copies.  We request that you also send a
separate copy of each comment to the contact person listed below (see
FOR FURTHER INFORMATION CONTACT).

Instructions:  Direct your comments to Docket ID No
EPA-HQ-RCRA-2005-0017.  The EPA's policy is that all comments received
will be included in the public docket without change and may be made
available online at   HYPERLINK "http://www.regulations.gov"
www.regulations.gov , including any personal information provided,
unless the comments include information claimed to be Confidential
Business Information (CBI) or other information the disclosure of which
is restricted by statute.  Do not submit information that you consider
to be CBI or otherwise protected through www.regulations.gov or e-mail.
Send or deliver information identified as CBI to the following address:
Ms. LaShan Haynes, RCRA Document Control Officer, EPA (Mail Code 5305W),
Attention Docket ID No. EPA-HQ-RCRA-2005-0017, 1200 Pennsylvania Avenue,
Washington DC, 20460.  Clearly mark the part or all of the information
that you claim to be CBI.  The   HYPERLINK "http://www.regulations.gov"
www.regulations.gov  website is an “anonymous access” system, which
means EPA will not know your identity or contact information unless you
provide it in the body of your comment.  If you send an e-mail comment
directly to EPA without going through www.regulations.gov, your e-mail
address will be automatically captured and included as part of the
comment that is placed in the public docket and made available on the
Internet.  If you submit an electronic comment, EPA recommends that you
include your name and other contact information in the body of your
comment and with any disk or CD-ROM you submit.  If EPA cannot read your
comment due to technical difficulties and cannot contact you for
clarification, EPA may not be able to consider your comment.  Electronic
files should avoid the use of special characters, any form of
encryption, and be free of any defects or viruses.  For additional
information about EPA’s public docket, visit the EPA Docket Center
homepage at   HYPERLINK "http://www.epa.gov/epahome/dockets.htm"
http://www.epa.gov/epahome/dockets.htm .  We also request that
interested parties who would like information they previously submitted
to EPA to be considered as part of this action identify the relevant
information by docket entry numbers and page numbers.

Docket: All documents in the docket are listed in the   HYPERLINK
"http://www.regulations.gov"  www.regulations.gov  index.  Although
listed in the index, some information is not publicly available, e.g.,
CBI or other information whose disclosure is restricted by statute.
Certain other material, such as copyrighted material, will be publicly
available only in hard copy.  Publicly available docket materials are
available either electronically in   HYPERLINK
"http://www.regulations.gov"  www.regulations.gov  or in hard copy at
the RCRA Docket, EPA/DC, EPA West, Room 3334, 1301 Constitution Ave.,
NW., Washington, DC.  The Public Reading Room is open from 8:30 a.m. to
4:30 p.m., Monday through Friday, excluding legal holidays. The
telephone number for the Public Reading Room is<PHONE_NUMBER>, and the
telephone number for the RCRA Docket is<PHONE_NUMBER>.

FOR FURTHER INFORMATION CONTACT:   Mary Jackson, Hazardous Waste
Minimization and Management Division, Office of Solid Waste, Mailcode:
5302P, Environmental Protection Agency, 1200 Pennsylvania Ave., NW,
Washington, D.C.  20460; telephone number:<PHONE_NUMBER>; fax number:
(703) 308-8433; email address:   HYPERLINK<EMAIL_ADDRESS><EMAIL_ADDRESS>.

SUPPLEMENTARY INFORMATION:

 General Information

A.  Does This Action Apply to Me?

Categories and entities potentially affected by this action include:

Category	NAICS code	SIC code	Examples of potentially regulated entities

Any industry that generatesor combusts hazardous waste as defined in the
proposed rule	562

327

325

324

331

333

326

488, 561

421

422

512, 541, 812

512, 514, 541, 711

924

336

928

334

339	49

32

28

29

33

38

306

49

50

51

73

89

95

37

97

35

38	Waste Management and Remediation Services

Non-metallic Mineral Products Manufacturing

Chemical Manufacturing

Petroleum and Coal Products Manufacturing

Primary Metals Manufacturing

Machinery Manufacturing

Plastic and Rubber Products Manufacturing

Administration and Support Services

Scrap and waste materials

Wholesale Trade, Non-durable Goods, N.E.C

Business Services, N.E.C.

Services, N.E.C.

Air, Water and Solid Waste Management

Transportation Equipment Manufacturing

National Security

Computer and Electronic Products Manufacturing

Miscellaneous Manufacturing

This table is not intended to be exhaustive, but rather provides a guide
for readers regarding entities likely to be impacted by this action.
This table lists examples of the types of entities EPA is now aware
could potentially be regulated by this action.  Other types of entities
not listed could also be affected.  To determine whether your facility,
company, business, organization, etc., is affected by this action, you
should examine the applicability criteria in this proposed rule.  If you
have any questions regarding the applicability of this action to a
particular entity, consult the person listed in the preceding FOR
FURTHER INFORMATION CONTACT section.

B.  What Should I Consider as I Prepare My Comments for EPA?

1.  Submitting CBI.  Do not submit this information to EPA through
www.regulations.gov or e-mail.  Clearly mark the part or all of the
information that you claim to be CBI.  For CBI information in a disk or
CD ROM that you mail to EPA, mark the outside of the disk or CD ROM as
CBI and then identify electronically within the disk or CD ROM the
specific information that is claimed as CBI.  In addition to one
complete version of the comment that includes information claimed as
CBI, a copy of the comment that does not contain the information claimed
as CBI must be submitted for inclusion in the public docket.
Information so marked will not be disclosed except in accordance with
procedures set forth in 40 CFR part 2.

2. Tips for Preparing Your Comments. When submitting comments, remember
to:

Identify the rulemaking by docket number and other identifying
information (subject heading, Federal Register date and page number).

Follow directions - The agency may ask you to respond to specific
questions or organize comments by referencing a Code of Federal
Regulations (CFR) part or section number.

Explain why you agree or disagree; suggest alternatives and substitute
language for your requested changes.

Describe any assumptions and provide any technical information and/or
data that y  TOC \o "1-3" \h \z \u   ou used.

If you estimate potential costs or burdens, explain how you arrived at
your estimate in sufficient detail to allow for it to be reproduced.

Provide specific examples to illustrate your concerns, and suggest
alternatives.

Explain your views as clearly as possible, avoiding the use of profanity
or personal threats.

Make sure to submit your comments by the comment period deadline
identified.

	3. Docket Copying Costs:

            You may copy a maximum of 100 pages from any regulatory
docket at no charge. Additional copies are 15 cents/page.

	4. How Do I Obtain a Copy of This Document and Other Related
Information?

In addition to being available in the docket, an electronic copy of
today’s proposed rule will also be available on the Worldwide Web
(WWW).  Following the Administrator’s signature, a copy of this
document will be posted on the WWW at   HYPERLINK
"http://www.epa.gov/hwcmact"  http://www.epa.gov/hwcmact .  This website
also provides other information related to the NESHAP for hazardous
waste combustors.

	5. Index of contents

The information presented in this preamble is organized as follows:

  TOC \o "1-4" \h \z \u    HYPERLINK \l "_Toc166653480"  Part One:
Background and Summary	  PAGEREF _Toc166653480 \h  6

  HYPERLINK \l "_Toc166653481"  I. Statutory Authority	  PAGEREF
_Toc166653481 \h  6

  HYPERLINK \l "_Toc166653482"  II. Background	  PAGEREF _Toc166653482
\h  7

  HYPERLINK \l "_Toc166653483"  A. What Is the Intent of Today’s
Proposed Rule?	  PAGEREF _Toc166653483 \h  7

  HYPERLINK \l "_Toc166653484"  B. Who Would Be Affected by Today’s
Proposed Rule?	  PAGEREF _Toc166653484 \h  7

  HYPERLINK \l "_Toc166653485"  C. What Is the Relationship between the
Proposed Rule and the Existing Exclusion for Comparable Fuel?	  PAGEREF
_Toc166653485 \h  8

  HYPERLINK \l "_Toc166653486"  1.  What Modifications to the Comparable
Fuel Exclusion May Be Warranted?	  PAGEREF _Toc166653486 \h  9

  HYPERLINK \l "_Toc166653487"  2.  How Has EPA Involved Stakeholders in
Discussions Regarding Potential Revisions to the Comparable Fuel
Exclusion?	  PAGEREF _Toc166653487 \h  10

  HYPERLINK \l "_Toc166653488"  A.  What Are the Conditions for
Exclusion of Emission-Comparable Fuel (ECF)?	  PAGEREF _Toc166653488 \h
11

  HYPERLINK \l "_Toc166653489"  B.  What Changes Is EPA Proposing to the
Conditions for Existing Comparable Fuel?	  PAGEREF _Toc166653489 \h  12

  HYPERLINK \l "_Toc166653490"  Part Two:  Rationale for the Proposed
Rule	  PAGEREF _Toc166653490 \h  13

  HYPERLINK \l "_Toc166653491"  I.  What Is the Rationale for Excluding
Emission-Comparable Fuel from the Definition of Solid Waste?	  PAGEREF
_Toc166653491 \h  13

  HYPERLINK \l "_Toc166653492"  A.  Why Would the Specifications Be
Waived Only for Hydrocarbons and Oxygenates?	  PAGEREF _Toc166653492 \h
15

  HYPERLINK \l "_Toc166653493"  B.  Do Available Data and Information
Support a Comparable Emissions Finding?	  PAGEREF _Toc166653493 \h  16

  HYPERLINK \l "_Toc166653494"  1.  Evaluation of Organic Emissions Data
for Hazardous Waste Boilers	  PAGEREF _Toc166653494 \h  16

  HYPERLINK \l "_Toc166653495"  2.  Evaluation of RCRA Risk Assessments
 PAGEREF _Toc166653495 \h  19

  HYPERLINK \l "_Toc166653496"  3.  Comparative Risk Assessment for
Dioxin/Furan	  PAGEREF _Toc166653496 \h  20

  HYPERLINK \l "_Toc166653497"  II.  What Conditions Would Apply to
Burners of Emission-Comparable Fuel?	  PAGEREF _Toc166653497 \h  21

  HYPERLINK \l "_Toc166653498"  A.  Why Isn’t a DRE Performance Test a
Critical Requirement to Ensure Good Combustion Conditions?	  PAGEREF
_Toc166653498 \h  22

  HYPERLINK \l "_Toc166653499"  B.  What Is the Rationale for the
Proposed Burner Conditions?	  PAGEREF _Toc166653499 \h  23

  HYPERLINK \l "_Toc166653500"  1.  ECF Must Be Burned in a Watertube
Steam Industrial or Utility Boiler That Is Not Stoker-Fired	  PAGEREF
_Toc166653500 \h  24

  HYPERLINK \l "_Toc166653501"  2.  CO Monitoring	  PAGEREF
_Toc166653501 \h  25

  HYPERLINK \l "_Toc166653502"  3.  The Boiler Must Fire at Least 50%
Primary Fuel	  PAGEREF _Toc166653502 \h  27

  HYPERLINK \l "_Toc166653503"  4.  The Boiler Load Must Be 40% or
Greater	  PAGEREF _Toc166653503 \h  28

  HYPERLINK \l "_Toc166653504"  5.  The ECF Must Have an As-Fired
Heating Value of 8,000 Btu/lb or Greater	  PAGEREF _Toc166653504 \h  28

  HYPERLINK \l "_Toc166653505"  6.  ECF Must Be Fired into the Primary
Fuel Flame Zone	  PAGEREF _Toc166653505 \h  29

  HYPERLINK \l "_Toc166653506"  7.  The ECF Firing System Must Provide
Proper Atomization	  PAGEREF _Toc166653506 \h  29

  HYPERLINK \l "_Toc166653507"  8.  Dioxin/Furan Controls for Boilers
Equipped with an ESP or FF	  PAGEREF _Toc166653507 \h  31

  HYPERLINK \l "_Toc166653508"  III. What Restrictions Would Apply to
Particular Hydrocarbons and Oxygenates?	  PAGEREF _Toc166653508 \h  34

  HYPERLINK \l "_Toc166653509"  A.  What is the Rationale for the
Relative Hazard Characterization Scheme?	  PAGEREF _Toc166653509 \h  34

  HYPERLINK \l "_Toc166653510"  B.  What Are the Results of the Relative
Hazard Ranking?	  PAGEREF _Toc166653510 \h  35

  HYPERLINK \l "_Toc166653511"  C.  What Firing Rate Restrictions Would
Apply to Benzene and Acrolein?	  PAGEREF _Toc166653511 \h  37

  HYPERLINK \l "_Toc166653512"  IV.  What Conditions Would Apply to
Storage of ECF?	  PAGEREF _Toc166653512 \h  38

  HYPERLINK \l "_Toc166653513"  A.  What Are the Proposed Storage
Conditions?	  PAGEREF _Toc166653513 \h  38

  HYPERLINK \l "_Toc166653514"  1.  Tank Systems, Tank Cars and Tank
Trucks	  PAGEREF _Toc166653514 \h  39

  HYPERLINK \l "_Toc166653515"  2.  Underground Storage Tank Systems
PAGEREF _Toc166653515 \h  52

  HYPERLINK \l "_Toc166653516"  3.  Closure of Tank Systems	  PAGEREF
_Toc166653516 \h  53

  HYPERLINK \l "_Toc166653517"  4.  Waiver of RCRA Closure for RCRA
Tanks That Become ECF Tanks	  PAGEREF _Toc166653517 \h  54

  HYPERLINK \l "_Toc166653518"  5.  Management of Incompatible Waste
Fuels and Other Materials	  PAGEREF _Toc166653518 \h  54

  HYPERLINK \l "_Toc166653519"  B.  What Other Options Did We Consider?
 PAGEREF _Toc166653519 \h  55

  HYPERLINK \l "_Toc166653520"  1.  Other Options We Considered to
Establish Storage Conditions for ECF	  PAGEREF _Toc166653520 \h  55

  HYPERLINK \l "_Toc166653521"  2. Consideration of Storage Controls for
Currently Excluded Comparable Fuels	  PAGEREF _Toc166653521 \h  55

  HYPERLINK \l "_Toc166653522"  V.  How Would We Assure That The
Conditions Are Being Satisfied?	  PAGEREF _Toc166653522 \h  56

  HYPERLINK \l "_Toc166653523"  A.  What Recordkeeping, Notification and
Certificate Conditions Would Apply to Generators and Burners?	  PAGEREF
_Toc166653523 \h  56

  HYPERLINK \l "_Toc166653524"  1. Waste Analysis Plans	  PAGEREF
_Toc166653524 \h  56

  HYPERLINK \l "_Toc166653525"  2. Sampling and Analysis	  PAGEREF
_Toc166653525 \h  57

  HYPERLINK \l "_Toc166653526"  3.  Speculative Accumulation	  PAGEREF
_Toc166653526 \h  57

  HYPERLINK \l "_Toc166653527"  4.  Notifications	  PAGEREF
_Toc166653527 \h  58

  HYPERLINK \l "_Toc166653528"  5. Burner Certification	  PAGEREF
_Toc166653528 \h  59

  HYPERLINK \l "_Toc166653529"  6. Recordkeeping	  PAGEREF _Toc166653529
\h  60

  HYPERLINK \l "_Toc166653530"  7.  Transportation	  PAGEREF
_Toc166653530 \h  61

  HYPERLINK \l "_Toc166653531"  8.  Ineligible RCRA Hazardous Waste
Codes	  PAGEREF _Toc166653531 \h  62

  HYPERLINK \l "_Toc166653532"  B. What If I Fail to Comply with
Conditions of the Exclusion?	  PAGEREF _Toc166653532 \h  62

  HYPERLINK \l "_Toc166653533"  C.  How Would Spills and Leaks Be
Managed?	  PAGEREF _Toc166653533 \h  63

  HYPERLINK \l "_Toc166653534"  D.  What Would Be the Time-Line for
Meeting the Proposed Conditions?	  PAGEREF _Toc166653534 \h  64

  HYPERLINK \l "_Toc166653535"  VI.  What Clarifications and Revisions
Are Proposed for the Existing Conditions for Exclusion of Comparable
Fuel?	  PAGEREF _Toc166653535 \h  64

  HYPERLINK \l "_Toc166653536"  VII.  What Are the Responses to Major
Comments of the Peer Review Panel?	  PAGEREF _Toc166653536 \h  65

  HYPERLINK \l "_Toc166653537"  A.  What Are the Reponses to Major
Comments Regarding the Comparable Emissions Rationale?	  PAGEREF
_Toc166653537 \h  65

  HYPERLINK \l "_Toc166653538"  B.  What Are the Reponses to Major
Comments Regarding the Application of the WMPT to Rank Comparable Fuels
Constituents?	  PAGEREF _Toc166653538 \h  73

  HYPERLINK \l "_Toc166653539"  Part Three:  State Authority	  PAGEREF
_Toc166653539 \h  77

  HYPERLINK \l "_Toc166653540"  I.  Applicability of the Rule in
Authorized States	  PAGEREF _Toc166653540 \h  77

  HYPERLINK \l "_Toc166653541"  II. Effect on State Authorization
PAGEREF _Toc166653541 \h  78

  HYPERLINK \l "_Toc166653542"  Part Four:  Costs and Benefits of the
Proposed Rule	  PAGEREF _Toc166653542 \h  79

  HYPERLINK \l "_Toc166653543"  I.  Introduction	  PAGEREF _Toc166653543
\h  79

  HYPERLINK \l "_Toc166653544"  II.  Baseline Specification	  PAGEREF
_Toc166653544 \h  79

  HYPERLINK \l "_Toc166653545"  III.  Analytical Methodology, Primary
Data Sources, and Key Assumptions	  PAGEREF _Toc166653545 \h  79

  HYPERLINK \l "_Toc166653546"  IV.   Key Analytical Limitations
PAGEREF _Toc166653546 \h  80

  HYPERLINK \l "_Toc166653547"  V.  Findings	  PAGEREF _Toc166653547 \h
81

  HYPERLINK \l "_Toc166653548"  Part Five:  Statutory and Executive
Order Reviews	  PAGEREF _Toc166653548 \h  82

  HYPERLINK \l "_Toc166653549"  I. Executive Order 12866: Regulatory
Planning and Review	  PAGEREF _Toc166653549 \h  82

  HYPERLINK \l "_Toc166653550"  II. Paperwork Reduction Act	  PAGEREF
_Toc166653550 \h  82

  HYPERLINK \l "_Toc166653551"  III. Regulatory Flexibility Act
PAGEREF _Toc166653551 \h  84

  HYPERLINK \l "_Toc166653552"  IV. Unfunded Mandates Reform Act of 1995
  PAGEREF _Toc166653552 \h  85

  HYPERLINK \l "_Toc166653553"  V.  Executive Order 13132: Federalism
PAGEREF _Toc166653553 \h  85

  HYPERLINK \l "_Toc166653554"  VI. Executive Order 13175: Consultation
and Coordination with Indian Tribal Governments	  PAGEREF _Toc166653554
\h  86

  HYPERLINK \l "_Toc166653555"  VII.  EO 13045 “Protection of Children
from Environmental Health Risks and Safety Risks”	  PAGEREF
_Toc166653555 \h  86

  HYPERLINK \l "_Toc166653556"  VIII. Executive Order 13211: Actions
Concerning Regulations that Significantly Affect Energy Supply,
Distribution, or Use	  PAGEREF _Toc166653556 \h  87

  HYPERLINK \l "_Toc166653557"  IX. National Technology Transfer
Advancement Act	  PAGEREF _Toc166653557 \h  87

Part One:  Background and Summary

I. Statutory Authority

These regulations are proposed under the authority of sections 2002,
3001, 3002, 3003, and 3004 of the Solid Waste Disposal Act of 1970, as
amended by the Resource Conservation and Recovery Act of 1976 (RCRA), as
amended by the Hazardous and Solid Waste Amendments of 1984 (HSWA), 42
U.S.C. 6921, 6922, 6923, and 6924.

II. Background

A. What Is the Intent of Today’s Proposed Rule?

Section 40 CFR 261.38 states that secondary materials (i.e., materials
that otherwise would be hazardous wastes) which have fuel value and
whose hazardous constituent levels are comparable to those found in the
fossil fuels which would be burned in their place are not solid wastes,
and hence not hazardous wastes.  We are proposing to amend the this
so-called comparable fuel exclusion by expanding the exclusion to
include fuels that are produced from a hazardous waste but which
generate emissions when burned in an industrial boiler that are
comparable to emissions from burning fuel oil.  In other words, the
fuels would be comparable from an emissions standpoint but not a
physical standpoint.  The revised rule would establish a new category of
excluded waste-derived fuel called emission-comparable fuel (ECF).

The quantity of waste fuels excluded under this approach would increase
substantially the amount of hazardous waste fuels that would eligible
for exclusion from the RCRA hazardous waste regulations.  Specifically,
we estimate that approximately 13,000 tons per year of waste fuels are
currently excluded under the existing comparable fuel exclusion, while
we project that up to an additional 94,000 130,000 tons per year may be
excluded under the exclusion being proposed today.

These additional hazardous secondary materials could be burned for
energy recovery without imposing unnecessary regulatory costs on
generators, primarily the manufacturing sector.  However, the expanded
comparable fuel exclusion may not substantially increase the amount of
hazardous waste burned for energy recovery because high Btu wastes, even
though not currently excluded from RCRA, are currently burned in
industrial furnaces and incinerators for their fuel value.  Nonetheless,
continuing to regulate these waste-derived fuels as hazardous wastes
would treat a potentially valuable fuel commodity (especially
considering the increasing value of fuels) as a waste without a
compelling basis.

B. Who Would Be Affected by Today’s Proposed Rule?

Entities that generate, burn, and store ECF are potentially affected by
this proposal.  The basic structure of the proposal is that ECF is no
longer a solid (and hazardous) waste, and hence that each of these
entities would not be subject to subtitle C regulation when managing
ECF.  Thus, generators of hazardous waste fuels that meet the conditions
of the ECF exclusion could manage these fuels without being subject to
subtitle C regulation assuming that the management conditions are
satisfied.  Burners, which are limited to certain industrial boilers
(including utility boilers), could burn ECF provided the boilers meet
the design and operating conditions in the proposed rule, as discussed
in Part II, Section II.  Generators would benefit from lower operating
costs because of lower (or eliminated) waste management fees and because
these fuels would substitute for fuels which would otherwise be
purchased.  In addition, entities storing ECF would not be subject to
subtitle C standards provided they satisfy the management conditions
tailored to ECF, as discussed in Part Two, Section IV.

Commercial hazardous waste combustors that are currently managing waste
fuels that qualify as ECF, on the other hand, might find themselves
unable to continue to charge hazardous waste management fees for the
excluded waste fuels.  Consequently, commercial hazardous waste
combustors might lose the waste management revenues for those diverted
fuels and may need to meet their heat input requirements by using other
waste fuels or fossil fuels.

C. What Is the Relationship between the Proposed Rule and the Existing
Exclusion for Comparable Fuel?

On June 19, 1998 (63 FR 33782 and §261.38), EPA promulgated standards
to exclude from the regulatory definition of solid waste certain
hazardous waste-derived fuels that meet specification levels for
hazardous constituents and physical properties that affect burning which
are comparable to the same levels in fossil fuels.  EPA’s goal was to
develop a comparable fuel specification which is useable by the
regulated community, but assures that an excluded waste-derived fuel is
similar in composition to commercially available fuel and therefore
poses no greater risk than burning fossil fuel.

During the eight years that the comparable fuel exclusion has been part
of the hazardous waste regulations, several stakeholders have pointed
out that many hazardous wastes with fuel value do not satisfy the terms
of the exclusion.  Independently, in 2003, EPA began examining the
effectiveness of the current comparable fuel program as part of an
effort to promote the energy conservation component of the Resource
Conservation Challenge to determine whether other hazardous wastes could
be appropriately excluded as comparable fuel.

As part of this effort, we contacted the American Chemistry Council
(ACC) in early 2003 to determine how much waste is currently excluded as
comparable fuel and whether there were additional quantities of other
high Btu wastes that could potentially be considered comparable fuel.
ACC conducted a survey of its members and provided results to EPA in
late 2003 indicating that approximately 13,000 tons per year of waste
fuels are currently excluded, but that approximately 190,000 tons per
year of additional waste fuels could potentially be excluded under
revisions to the exclusion.

Therefore, ACC recommended that EPA consider approaches to address the
following barriers perceived as excluding additional quantities of waste
fuels:

Analytic Issues:  High analysis cost and matrix interferences hamper
meeting the detection limit requirements for nondetected analytes in
many waste fuel matrices.

Over-Rigid Specifications:  Wastes containing nonhalogenated organics
and oxygenates do not result in emissions greater than burning waste
fuel meeting the specification if the combustor operates under good
combustion conditions.

Blending:  The current exclusion bans blending to meet hazard
constituent specifications.  Flexibility is needed on blending of
streams containing low levels of constituents, such as chromium and
manganese attributable to corrosion from stainless steel vessels and
pipes.

1.  What Modifications to the Comparable Fuel Exclusion May Be
Warranted?

We are proposing in this action to expand the exclusion for comparable
fuel to establish a new category of excluded fuel—emission-comparable
fuel (ECF).  This proposal would exclude waste fuels that generate
emissions, when burned in an industrial boiler, which are comparable to
emissions from burning fuel oil.  ECF would be subject to the same
hazardous constituent and other specifications in Table 1 to §261.38
that currently apply to comparable fuels, except that the specifications
for certain hydrocarbons and oxygenates would not apply.  The exclusion
would be based on the rationale that ECF has substantial fuel value,
that the hydrocarbon and oxygenate constituents no longer subject to a
specification add fuel value, and that emissions from burning ECF in an
industrial boiler operating under good combustion conditions are likely
not to differ from emissions from burning fossil fuels under those same
conditions.  As a result, the current specifications limiting the
hydrocarbons and oxygenates appear to be unnecessary.

The exclusion would be conditioned on the ECF being burned and stored
under certain conditions, including:  (1) design and operating
conditions for the ECF boiler that ensure that the ECF is burned under
the good combustion conditions typical for oil-fired industrial boilers;
and (2) conditions for storage in tanks which are comparable to those
for storage of fuels and organic liquids and which are tailored for the
hazards that ECF may pose given that ECF can have higher concentrations
of certain hydrocarbons and oxygenates than fuel oil and gasoline.

We are not proposing revisions to the comparable fuel exclusion to
address the analytical and blending recommendations raised by ACC.

a.  Why Are We Not Proposing Revisions to Address Analytic Concerns?
The specifications in Table 1 to §261.38 for volatile organic compounds
that were not detected in fuel oil or gasoline were based on the low
levels of detection achievable for fuel oil rather than the much higher
levels of detection achievable for gasoline.  Given that only benzene,
toluene, and naphthalene were detected, EPA used this approach for most
of the volatile organic compounds.  EPA acknowledged this deviation from
establishing the specification for nondetected compounds as the highest
level of detection in a benchmark fuel and explained that the levels of
detection for volatile compounds in gasoline were inflated because of
matrix effects.  ACC suggested that EPA consider the fact that many
waste fuels may pose the same matrix effects as gasoline, such that the
fuel oil-based specifications would not be reasonably achievable.

We believe that it would not be appropriate to consider increasing the
specifications for all volatile organic compounds and base them on the
higher levels of detection in gasoline rather than fuel oil levels of
detection because most of the compounds would simply not be expected to
be found in fuel oil or gasoline.  Rather, only certain hydrocarbons
would be expected to be in these fuels.  We could potentially also
consider oxygenates, however, because they are within a class of
compounds that are added to fuels to enhance combustion.  It appeared,
however, that this revision would not likely result in additional
hazardous waste fuel being conditionally excluded.  There were very few,
if any, waste fuels that meet the specifications for all volatile
compounds, except for the enumerated hydrocarbons and oxygenates, and
that also could meet revised, higher specifications for the hydrocarbons
and oxygenates based on the levels of detection in gasoline.
Consequently, we are not pursuing this approach further but,
nonetheless, solicit comment on such an approach.

b.  Why Are We Not Proposing Revisions to Address Blending Concerns?   A
condition of the existing comparable fuel exclusion is that blending to
meet the specification (except for viscosity) is prohibited to preclude
dilution to avoid treatment.  ACC noted that waste fuels often contain
incidental contamination of metals, such as chromium and manganese from
corrosion of stainless steel vessels and pipes, and that blending to
meet the specifications for low levels of metals appears reasonable.  We
believe that blending to meet the specifications for metals is
explicitly prohibited because it would be inconsistent with the section
3004(m) hazardous waste treatment provisions (which, although not
directly applicable, articulate important overall statutory objectives)
which require hazardous constituents to be removed or destroyed by
treatment, not diluted.  See 63 FR at 33795.

We believe, however, that blending to meet the specification for organic
compounds that may be present in fuel oil or
gasoline—hydrocarbons—or that are within a class of compounds that
are added to fuels to enhance combustion—oxygenates—could be
considered.  These compounds would not be diluted to avoid treatment;
they would still be treated by combustion.  However, it appears that
there were very few, if any, additional waste fuels that would be
excluded under such a blending provision.  Consequently, we are not
pursuing this approach further but, nonetheless, Nonetheless, we solicit
comment on such an approach and its applicability to additional waste
fuels.

2.  How Has EPA Involved Stakeholders in Discussions Regarding Potential
Revisions to the Comparable Fuel Exclusion?

On December 15, 2005, EPA convened a public meeting of stakeholders to
discuss potential revisions to the comparable fuel exclusion under 40
CFR 261.38.  Meeting notes are available in the docket for this
rulemaking.  Participants in the stakeholder meeting raised several
issues during the meeting and our responses are included in the meeting
notes.  In addition, several participants submitted written comments
after the meeting.  These comments and our responses are available in
the docket to today’s proposal.

III. Summary of the Proposed Rule

Today’s proposed rule would expand the comparable fuel exclusion by
conditionally waiving the specifications for certain hydrocarbons and
oxygenates listed in Table 1 to §261.38.  This excluded waste fuel
would be called emission-comparable fuel.  We are also proposing to
clarify the regulatory status of existing comparable fuel that no longer
meets the conditions of the exclusion.

A.  What Are the Conditions for Exclusion of Emission-Comparable Fuel
(ECF)?

ECF is a fuel derived from hazardous waste but which would be excluded
from the RCRA hazardous waste regulations if it meets prescribed
specifications and management conditions.  The ECF specifications would
be the same as those that are applicable to comparable fuel, except the
specifications for particular hydrocarbons and oxygenates would not
apply.  See proposed §261.38(a)(2).  The exclusion would apply from the
point that ECF meets the specifications.

Special conditions of the exclusion specific to ECF would include the
following design and operating conditions for the ECF burner:  (1) the
burner must be a watertube steam boiler other than a stoker-fired
boiler; (2) carbon monoxide (CO) must be monitored continuously, must be
linked to an automatic ECF feed cutoff system, and must not exceed 100
ppmv on an hourly rolling average (corrected to 7% oxygen); (3) the
boiler must fire at least 50% primary fuel on a heating value or volume
basis, whichever results in a higher volume of primary fuel, and the
primary fuel must be fossil fuel or tall oil with a heating value not
less than 8,000 Btu/lb; (4) the boiler load must be 40% or greater; (5)
the ECF must have an as-fired heating value of 8,000 Btu/lb or greater;
(6) ECF must be fired into the primary fuel flame zone; (7) the ECF
firing system must provide proper atomization; and (8) if the boiler is
equipped with an electrostatic precipitator (ESP) or fabric filter (FF)
and does not fire coal as the primary fuel, the combustion gas
temperature at the inlet to the ESP or FF must be continuously
monitored, must be linked to the automatic ECF feed cutoff system, and
must not exceed 400°F on an hourly rolling average.  See proposed
§261.38(c)(2).  (Please note that we specifically request comment on
several of these proposed conditions, as discussed later.) The principal
conditions that would apply to ECF boilers—waterwall steam boiler, low
CO, burning high Btu primary fuel that is properly atomized, operating
at boiler loads above 40%—reflect design and operating conditions
typical for oil-fired industrial boilers that operate under good
combustion conditions.

In addition, ECF must be stored in tanks, tank cars, or tank trucks.
See proposed §261.38(c)(1).  These tank systems, tank cars, and tank
trucks would be excluded from regulation if they meet conditions similar
to those which apply to fuel oil (the product most analogous to ECF),
along with additional conditions necessary to minimize the potential for
releases to the environment accounting for the differences between ECF
and fuel oil.  These include:  (1) certain provisions of the Spill
Prevention, Control, and Countermeasures (SPCC) requirements applicable
to oils under §§112.2, 112.5, 112.7, and 112.8; (2) secondary
containment and leak detection requirements for tank systems, including
use of liners, vaults, or double-walled tanks; (3) preparedness and
prevention, emergency procedures, and response to release provisions
adopted from requirements applicable to tank systems that store
hazardous waste, and (4) fugitive air emission technical controls
adopted from Subpart EEEE, Part 63, for organic liquids distribution
(which would apply not only to any hazardous air pollutants among the
oxygenates and hydrocarbons, but also would apply to the 11 oxygenates
for which there would be no specification in this proposed rule and
which are hazardous constituents under RCRA having significant vapor
pressure but which are not hazardous air pollutants under the CAA).
Underground tanks storing ECF are subject to the applicable requirements
of 40 CFR Part 280.  A further condition of the exclusion is that the
generator must document in the waste analysis plan how precautions will
be taken to prevent mixing of ECF and other materials which could result
in adverse consequences from incompatible materials.  In addition, to be
excluded, ECF would need to meet all of the conditions applicable to the
existing comparable fuel, including:  (1) the specifications under Table
1 to 261.38, except for the specifications for certain hydrocarbons and
oxygenates; (2) prohibition on blending to meet the specifications,
except for viscosity; (3) notifications to state RCRA and Clean Air Act
(CAA) Directors and public notification; (4) waste analysis plans; (5)
sampling and analysis conditions; (6) prohibition on speculative
accumulation; (7) recordkeeping; (8) burner certification to the
generator; and (9) ineligible waste codes.

ECF that has lost its exclusion because of failure to satisfy a
condition of the exclusion must be managed as a hazardous waste from the
point of ECF generation.  In addition, ECF that is spilled or leaked and
cannot be burned under the conditions of the exclusion is a waste (it is
a hazardous waste if it exhibits a characteristic of hazardous waste or
if the ECF were derived from a listed hazardous waste) and must be
managed in accordance with existing federal and state regulations.
Furthermore, if an ECF tank system ceases to be operated to store ECF
product, but has not been cleaned by removing all liquids and
accumulated solids within 90 days of cessation of ECF storage
operations, the tank system would become subject to the RCRA subtitle C
hazardous waste regulations.  (This is the same principle that applies
to any product storage unit when it goes out of service.  See
§261.4(c).)  Liquids and accumulated solids removed from a tank system
that ceases to be operated for storage of ECF product are waste (they
are hazardous wastes if they exhibit a characteristic of hazardous waste
or if the ECF were derived from a listed hazardous waste).

B.  What Changes Is EPA Proposing to the Conditions for Existing
Comparable Fuel?

The proposed rule would restructure the current conditions for
comparable fuel (and syngas fuel) to make the regulatory language more
readable given that the regulation must accommodate the proposed
exclusion for ECF.  Consequently, we are redrafting the entire section
for clarity.  In addition, we are making technical corrections to
several provisions of the rule.  We regard these language changes as
purely technical, and thus will accept comment only on whether the
suggested language change expresses the current meaning of the
provision.  We are not reexamining, reconsidering, or otherwise
reopening these provisions for comment.

We are, however, proposing to amend several provisions that apply to
comparable fuel for the same reasons that we are proposing to apply the
amended provisions to ECF.  We specifically request comment on whether
these clarifications and conforming amendments are appropriate:

We are proposing to clarify the consequences of failure to satisfy the
conditions of the existing comparable fuel exclusion.  The material must
be managed as hazardous waste from the point of generation.  In
addition, we are proposing to clarify that excluded fuel that is spilled
or leaked and that no longer meets the conditions of the exclusion must
be managed as a hazardous waste if it exhibits a characteristic of
hazardous waste or if it was derived from a listed hazardous waste when
the exclusion was claimed.  See proposed §261.38(d).

We are proposing to clarify the status of tanks that cease to be
operated as comparable fuel storage tanks.  The tank system becomes
subject to the RCRA hazardous waste facility standards if not cleaned of
liquids and accumulated solids within 90 days of ceasing operations as a
comparable fuel tank.  In addition, we are proposing to clarify that
liquids and accumulated solids removed from the tank after the tank
ceases to be operated as a comparable fuel product tank must be managed
as hazardous waste if they exhibit a characteristic of hazardous waste
or if they were derived from a listed hazardous waste when the exclusion
was claimed.  See proposed §261.38(b)(13).

We are proposing to waive the RCRA closure requirements for tank systems
that are used only to store hazardous wastes that are subsequently
excluded as comparable fuel.  See proposed §261.38(b)(14).

We are proposing to clarify the regulatory status of boiler residues,
including bottom ash and emission control residue.  Burning excluded
fuel that was derived from a listed hazardous waste does not subject
boiler residues to regulation as derived-from hazardous waste.  See
§261.38(b)(12).

We are proposing that the one-time notice by the generator to regulatory
officials include an estimate of the average and maximum monthly and
annual quantity of waste for which an exclusion would be claimed.  See
proposed §261.38(b)(2)(i)(D).

Part Two:  Rationale for the Proposed Rule

I.  What Is the Rationale for Excluding Emission-Comparable Fuel from
the Definition of Solid Waste?

	Emission-comparable fuel (ECF) is a fuel derived from hazardous waste,
but which would be excluded from RCRA hazardous waste regulation if it
meets prescribed specifications and management conditions.  The ECF
specifications would be the same as those that currently apply to
existing comparable fuel, except the specifications for particular
hydrocarbons and oxygenates would not apply.  See proposed
§261.38(a)(2).

The exclusion would be based on the rationale that ECF has fuel value,
that the hydrocarbon and oxygenate constituents no longer subject to a
specification themselves have fuel value, and that emissions from
burning ECF in an industrial boiler operating under good combustion
conditions are likely not to differ from emissions from burning fossil
fuels under those same conditions.  Emissions from burning ECF in an
industrial boiler operating under good combustion conditions would be
comparable to emissions from burning fuel oil in an industrial boiler
operating under the same good combustion conditions because operating a
boiler under good combustion conditions, evidenced by carbon monoxide
(CO) emissions below 100 ppmv (on an hourly rolling average), assures
the destruction of organic compounds generally to trace levels,
irrespective of the type or concentration of the organic compound in the
feed.  As hydrocarbons are oxidized during combustion, eventually
(ideally) to carbon dioxide and water, CO is formed just prior to
complete oxidation to carbon dioxide.  Because CO is difficult to
oxidize, it is the rate-limiting step in the oxidation process.  Thus,
low CO levels indicate good combustion and low levels of organic
compounds.

EPA has discretion to classify such material as a fuel product, and not
as a waste.  See generally Safe Foods and Fertilizer v. EPA, 350 F. 3d
1263, 1269-71 (D.C. Cir. 2004) (secondary materials physically
comparable to virgin products which would be used in their place, or
which pose similar or otherwise low risks when used in the same manner
as the virgin product, need not be considered “discarded” and hence
need not be classified as solid wastes).  Given that ECF (including the
hydrocarbon and oxygenate portion) would have legitimate energy value
and that emissions from burning ECF are comparable to fuel oil when
burned in an industrial boiler under the good combustion conditions
typical of such boilers, classifying such material as a fuel product and
not as a waste promotes RCRA’s resource recovery goals without
creating a risk from burning greater than those posed by fossil fuel.
Under these circumstances, EPA can permissibly classify ECF as a
nonwaste.

The conditional exclusion would be an exclusion only from the RCRA
subtitle C regulations, and not from the emergency, remediation and
information-gathering sections of the RCRA statute [sections 3007, 3013,
and 7003].  This is consistent with the principle already codified for
other excluded hazardous secondary materials—that the exclusion is
only from the RCRA regulatory provisions, and not from these statutory
authorities.  See §261.1(b).  We are restating this principle here in
the interest of clarity, not to reopen the issue.  The legal basis for
the distinction of the Agency’s authority under these provisions is
that they use the broader statutory definition of solid waste (and
hazardous waste, as well) and so need not (and should not) be read as
being limited by the regulatory definition.  See, for example, 50 FR at
627.  See also Connecticut Coastal Fishermen’s Assn. v. Remington
Arms, 989 F. 2d 1305, 1313–15 (2d Cir. 1993) (EPA may permissibly
ascribe different definitions to the term ‘‘solid waste’’ for
regulatory

and statutory purposes).

Although ECF could have higher concentrations of particular hydrocarbons
and oxygenates than the benchmark fossil fuels—fuel oil and
gasoline—that EPA used to establish the specifications in Table 1 to
§261.38, higher levels of hydrocarbons and oxygenates in ECF do not
imply that burning ECF for energy recovery constitutes waste management
because:  (1) hydrocarbons naturally occur in virgin fuels and
oxygenates are a class of compounds that are added to virgin fuels to
enhance combustion; (2) the hydrocarbons and oxygenates have a heating
value of 10,000 Btu/lb to 18,500 Btu/lb, which is comparable to the
range for virgin fuels (e.g., coal and fuel oil); and (3) the
hydrocarbons and oxygenates produce emissions comparable to virgin fuels
when burned under conditions typical of those under which virgin fuels
are burned.

We note, however, that ECF can pose a greater hazard during storage than
fuel oil given that ECF can contain higher concentrations of certain
hazardous toxic, volatile hydrocarbons and oxygenates.  We are
consequently proposing to condition the exclusion on certain storage
conditions similar to those applicable to commercial products and
commodities analogous to ECF, namely fuel oil and other commercial
organic liquids.  See discussion below in Part Two, Section IV.

In addition, we are proposing to condition the exclusion on requirements
for the design and operation of the ECF burner to ensure that ECF is
burned under the good combustion conditions typical of most fossil fuel
boilers.  See discussion below in Part Two, Section II.  These
conditions should ensure that emissions from burning ECF remain
comparable to emissions from burning fossil fuels.

A.  Why Would the Specifications Be Waived Only for Hydrocarbons and
Oxygenates?

	We are proposing not to apply the specifications for certain
hydrocarbons and oxygenates, but are proposing to retain the
specifications for metals and the other categories of organic compounds
for which specifications are provided under §261.38.  We would not
apply the specifications for these hydrocarbons because:  (1) it is
reasonable to assume that these compounds may be present in fossil fuels
(see 63 FR at 33791); and (2) when they are burned under the good
combustion conditions typical for fossil fuel-fired boilers, emissions
from burning these compounds would be comparable to emissions from
burning fuel oil.

We also would not apply the specifications for the listed oxygenates
because they are a class of organic compounds that are added to fuels to
enhance combustion.  These compounds would burn cleanly under the good
combustion conditions typical of a fuel oil-fired industrial boiler and
would generate only trace or comparable levels of emissions.

	It is appropriate to retain the specifications for metals since they do
not contribute energy and are not destroyed during the combustion
process.  Given that the metal specifications in Table 1 to §261.38
reflect levels that can be present in fuel oil, excess, noncontributing
metals are “along for the ride,” suggesting discarding.  Moreover,
metals emissions would necessarily be higher than emissions from fuel
oil if the metals specifications do not apply because oil-fired boilers
typically lack optimized particulate control due to low metal content of
commercially available fuel oils.

	Also, it is appropriate to retain the specifications for the other
categories of organic compounds listed under Table 1 to
§261.38—sulfonated organics, nitrogenated organics, and halogenated
organic compounds.  These organic compounds, for the most part, are not
likely to be found in the benchmark fuels—fuel oil and gasoline—we
used to establish the specifications.  And, unlike oxygenates, these
organic compounds are not within a class of compounds that are added to
fossil fuels to enhance combustion.  These toxics  hazardous compounds
also would appear to be along for the ride when present at
concentrations higher than benchmark fuels, and consequently their
destruction via combustion can be viewed as waste management.

B.  Do Available Data and Information Support a Comparable Emissions
Finding?

	We investigated whether emissions from burning ECF in an industrial
boiler operating under prescribed good combustion conditions would be
comparable to emissions from burning fuel oil in an industrial boiler
operating under good combustion conditions.  We evaluated organic
emissions data from watertube steam boilers (other than stoker-fired
boilers) burning hazardous waste and compared those emissions against
emissions from oil-fired industrial boilers.  In addition, we conducted
two qualitative analyses of the risk that ECF emissions may pose:  (1)
evaluation of RCRA risk assessments for watertube steam boilers burning
hazardous waste to determine if organic emissions had been found to pose
a hazard to human health and the environment; and (2) a limited
comparative risk assessment for dioxin/furan emissions.

	As discussed below, we believe that available data and information
indicate that emissions from burning ECF under the proposed, prescribed
conditions would be comparable to emissions from an oil-fired industrial
watertube steam boiler operating under good combustion conditions.

1.  Evaluation of Organic Emissions Data for Hazardous Waste Boilers

	In the absence of emissions data from boilers burning ECF, we evaluated
organic emissions data from watertube steam boilers burning hazardous
waste and compared those emissions against emissions from oil-fired
industrial boilers.  Using hazardous waste boiler emissions as a
surrogate for ECF boiler emissions is a reasonable worst-case because
the exclusion would be conditioned on the ECF boiler operating under
conditions relating to assuring good combustion conditions that are at
least as stringent as those required of boilers burning hazardous waste.

	We obtained organic emissions data for 26 hazardous waste watertube
steam boilers which data were generated during risk-burn testing
required under RCRA omnibus authority codified at §270.32(b)(2).  EPA
requires this testing as necessary on a site-specific basis to ensure
that emissions are protective of human health and the environment.  We
have data for 28 test conditions for the 26 boilers that provide 175
detected measurements of organic compounds, where a measurement is a
three-run set.  We also have data for hazardous organic compounds
emitted from oil-fired industrial boilers.  Those data were compiled in
support of the NESHAP for Industrial, Commercial, and Institutional
Boilers and Process Heaters promulgated under Part 63, Subpart DDDDD.
See 69 FR 55218 (Sept. 13, 2004).  We use oil-fired industrial boiler
emissions data for comparison because fuel oil is the closest analogous
fuel to ECF, and ECF could be burned only in industrial or utility
boilers.  See discussion below in Section II.B.1.

We have emissions data for both hazardous waste boilers and oil-fired
industrial boilers for 26 toxic hazardous organic compounds.  We also
have hazardous waste boiler emissions data for another 33 toxic
hazardous organic compounds for which we do not have oil-fired boiler
emissions data for comparison.  We discuss our investigation of these
data below.

a.  ToxicHazardous Organic Compounds for Which We Have Both Hazardous
Waste Boiler and Fuel Oil Boiler Emissions Data.  We have both hazardous
waste boiler and fuel-oil boiler emissions data for 26 toxic hazardous
organic compounds.  The great majority of the hazardous waste boiler
test condition averages for these compounds (150, or greater than 85%)
were unequivocally comparable to fuel oil emissions—the hazardous
waste emissions were below the oil emissions 95th percentile level.
There were 24 test condition averages, however, that exceeded the oil
emissions 95th percentile level for 10 compounds.  Nonetheless, we do
not believe that these exceedances indicate that ECF emissions would be
higher than oil-fired boiler emissions, as discussed below.

For 12 of the 24 exceedances, laboratory contamination of the sample was
known or suspected.  Specifically, for nine exceedances—six for
dichloromethane, two for benzene, and one for toluene—the constituent
being measured was found in the blank, while there were three additional
exceedances for dichloromethane, a common lab contaminant that is
frequently found in laboratory samples and in the environment.  For one
of these test conditions, the report indicated that dichloromethane is a
common laboratory contaminant, implying that the data may be suspect.
For the other two test conditions, laboratory contamination was not
discussed in the test reports.  Even if laboratory contamination were
not an issue for these two tests, however, we note that these hazardous
waste boilers were not operating under the conditions that are proposed
for an ECF boiler.  Both boilers were burning waste fuels with a heating
value below the 8,000 Btu/lb minimum heating value that is proposed for
ECF.  In addition, it is unclear if one boiler was burning vent gas or
natural gas as the primary fuel.  ECF must be burned with at least 50%
primary fuel that is fossil fuel.  Operating under conditions less
stringent than proposed for ECF boilers could result in higher emissions
of organic compounds.

For seven exceedances, hazardous waste boiler emissions were at trace
levels—there was a de minimis increase in emissions.  Test condition
averages were below 8 ug/dscm for the exceedances for anthracene,
benzo[a]pyrene, ethylbenzene, fluorine, 2-methlynaphthalene, and
phenanthrene.

In addition, an exceedance for acetaldehyde was at an emissions level of
100 ug/dscm, while oil emission levels for acetaldehyde are virtually
comparable at 70 ug/dscm.  However, the hazardous waste boiler emissions
for acetaldehyde were well below the 95th percentile emissions for
natural gas boilers, 635 ug/dscm.  This is relevant because ECF may be
burned with natural gas as the primary fuel.  Further, we note that the
hazardous waste boiler was operating under conditions less stringent
than proposed for ECF boilers—it was burning only 20% natural gas as
the primary fuel, while it is proposed that ECF boilers fire at least
50% primary fuel.  Thus, acetaldehyde emissions may be higher than they
would have been if the boiler had the hot, stable flame that burning 50%
natural gas (or fuel oil) would provide.

Finally, there were four exceedances for benzene that we nonetheless
believe are comparable to fuel oil emissions.  Three of the exceedances
were below the highest fuel oil emission test run level of 200 ug/dscm,
while the fourth exceedance was at a level of 260 ug/dscm, just somewhat
higher.  Moreover More importantly, for all four exceedances, the
hazardous waste boiler was not operating under the conditions proposed
for an ECF boiler.  For all four exceedances, the hazardous waste fuel
had a heating value below 2,000 Btu/lb compared to 8,000 Btu/lb that is
proposed for ECF.  And, for one of the exceedances, the hazardous waste
fuel had a viscosity of 165 cSt, while the maximum viscosity for ECF
would be 50 cSt.  To reiterate, operating under conditions less
stringent than proposed for ECF boilers could result in higher emissions
of organic compounds.

Notwithstanding this analysis of available emissions data, we
acknowledge that, when ECF with higher concentrations of certain
hydrocarbons and oxygenates than fuel oil is burned even under good
combustion conditions, emissions of toxic hazardous organics may be
somewhat higher than those from burning fossil fuel.  This is because
combustion is generally a percent-reduction process.  Thus, even though
good combustion conditions may ensure a very high destruction efficiency
(e.g., 99.9999 % reduction), emission concentrations may nonetheless
increase as the feedrate of an organic compound increases.  We believe,
however, that these increases would be de minimis because operating
under the good combustion conditions proposed for ECF boilers ensures
that emissions of toxic hazardous organic compounds would generally be
at trace levels, and, as discussed below, protective of human health and
the environment.

b. Compounds for Which We Only Have Hazardous Waste Boiler Emissions
Data.  We have hazardous waste boiler emissions data for 33 toxic
hazardous organic compounds for which we do not have oil-fired boiler
emissions data for comparison.  Average hazardous waste boiler emissions
for each of these compounds are at trace levels—below 11
ug/dscm—except for bis(2-ethylhexyl)phthalate and chloroform.

We have bis(2-ethylhexyl)phthalate emissions data for 15 test conditions
(generally comprised of three runs) representing 15 different boilers.
Test condition average emissions ranged from 0.34 ug/dscm to 600 ug/dscm
for the boilers, with an average of 69 ug/dscm.  Although the highest
test condition average—600 ug/dscm—appeared to be an outlier given
that the second highest average was 130 ug/dscm and 12 test conditions
were below 42 ug/dscm, we determined that it is not a statistical
outlier.  Nonetheless, we note that:  (1) the boiler with the highest
emissions—600 ug/dscm—was not operating under the conditions that
are proposed for an ECF boiler (which could result in higher
emissions)—the primary fuel firing rate was approximately 30% rather
than a minimum of 50%, and boiler load was approximately 30% rather than
a minimum of 40%; and (2) bis(2-ethylhexyl)phthalate is known to be a
common lab contaminant, and thus the reported emissions levels may be
suspect.

For chloroform, we have emissions data for 9 test conditions (generally
comprised of three runs) representing 9 different boilers.  Test
condition average emissions ranged from 0.28 ug/dscm to 270 ug/dscm for
the boilers, with an average of 45 ug/dscm.  Although the highest test
condition average—270 ug/dscm—appeared to be an outlier given that
the second highest average was 85 ug/dscm and the remaining test
conditions did not exceed 16 ug/dscm, we determined that it is not a
statistical outlier.  We note, however, that the boiler with the highest
emissions—270 ug/dscm—was not operating under the conditions that
are proposed for an ECF boiler—it burned a waste fuel with a heating
value below 8,000 Btu/lb and it is not clear whether the boiler burned
process vent gas or natural gas as primary fuel.

2.  Evaluation of RCRA Risk Assessments

	In addition to the analysis of emission concentrations discussed above,
we reviewed the RCRA risk assessments that had been completed by June
2006 for hazardous waste watertube steam boilers other than stoker-fired
boilers to determine if organic emissions under the good combustion
conditions required by the standards under Part 266, Subpart H, may
result in unacceptable risk to human health and the environment.  We
determined that such risk assessments had been conducted at13 facilities
and decisions on whether omnibus/additional permit conditions are needed
to ensure emissions are protective have been made for nine of those
facilities.  A decision to include an omnibus permit condition to
address organic emissions has been made for only two of the nine
facilities, however.

The first facility operated several boilers equipped with a common
electrostatic precipitator.  Risk-based dioxin emission limitations and
associated testing and temperature monitoring requirements were
established in the permit based upon a finding that dioxin/furan
emissions during an isolated test event exceeded risk levels of concern.
 During that test event, artificial chlorine spiking into the waste feed
was conducted.  During subsequent testing under the permit terms,
chlorine spiking did not take place and compliance with the risk-based
dioxin/furan emission limitations was demonstrated.  Electrostatic
precipitator operating temperatures during the subsequent tests ranged
from 396°F to 418°F.  We note, however, that the chlorine
specification proposed for ECF would prohibit chlorine concentrations
from approaching the levels present during the instances of chlorine
spiking at this facility.  In addition, we also note that today’s
proposal would require that ECF boilers (other than coal-fired boilers)
equipped with an ESP or FF maintain a gas temperature below 400 F as a
condition of the exclusion.  See discussion in Section II below.

For the second facility where omnibus permit conditions were imposed,
there was no finding of excess risk associated with any organic
constituents.  Rather, the omnibus permit conditions serve as a trigger
for a reassessment of risk if emissions levels higher than those
considered in the initial risk assessment were measured.

This analysis confirms our view that organic emissions from hazardous
waste boilers operating under good combustion conditions required under
§§266.104 and 63.1217 are generally protective.  It also confirms our
view that organic emissions from ECF boilers operating under the good
combustion conditions discussed in Section II below should be
protective.

3.  Comparative Risk Assessment for Dioxin/Furan

Finally, we also conducted an abbreviated comparative risk assessment
for dioxin/furan emissions from boilers burning hazardous waste and that
meet the design conditions for an ECF boiler discussed below in Section
II—watertube steam boiler that is not stoker-fired.  The abbreviated
evaluation used one component of the comparative risk evaluation used to
support the Phase II hazardous waste combustor MACT for boilers--the
Margin of Exposure (MOE) analysis.   The emission-adjusted MOE analysis
uses the risk “safety margins” (i.e., modeled MOEs) determined from
the MACT Phase I comprehensive risk assessment for hazardous waste
incinerators to determine whether, considering emissions alone, risks
for a second universe, here, the ECF boilers, could rise to a level of
concern.  Smaller MOEs correspond to a greater potential for risk beyond
the level of concern (i.e., 1E-05 lifetime cancer risk).  In this
analysis, we:  (1) revised the dioxin/furan emissions data base for
Phase II hazardous waste boilers to establish a data base of boilers
that meet the ECF boiler design conditions (i.e., by eliminating boilers
other than watertube steam boilers that are not stoker-fired) and by
adding dioxin/furan emissions data obtained during the evaluation of
risk burns for hazardous waste boilers, as discussed above; (2)
calculated point estimates and confidence intervals for the revised
emissions data base; (3) combined the Phase I incinerator data base with
the revised (i.e., ECF) boiler data base and conducted tests for common
generalized percentiles; and (4) adjusted the MOE, if appropriate.  The
analysis indicates that the emissions-adjusted MOEs representing the ECF
boilers are higher than the MOEs for the Phase I incinerators.  This
suggests a lower potential for risk for the ECF boilers compared to
hazardous waste incinerators.  This means that, within the limitations
of the analyses, dioxin/furan emissions from ECF boilers pose no greater
hazard than the emissions from hazardous waste incinerators, and
therefore, should remain within levels that are protective.

Based on this information—comparison of emissions concentrations from
hazardous waste boilers and oil-fired boilers; evaluation of omnibus
risk assessments; and evaluation of dioxin/furan risk—we conclude that
emissions from burning ECF in a boiler under the conditions proposed
today would be comparable to fuel oil emissions and would be generally
protective of human health and the environment.  We specifically request
additional data and comment on our analyses and conclusions.

II.  What Conditions Would Apply to Burners of Emission-Comparable Fuel?

	The ECF exclusion proposed today would be conditioned on burning ECF
under conditions typical of a fuel oil-fired industrial boiler operating
under good combustion conditions.  The ECF conditions would ensure that
the boiler maintains a hot, stable flame, and that ECF is properly
atomized and fired into that flame.  In addition, post-combustion
conditions would minimize the potential for dioxin/furan formation by
controlling the combustion gas temperature at the inlet to a dry
particulate matter control device for boilers so-equipped.  Accordingly,
we propose the following conditions:  (1) the burner must be a watertube
steam boiler other than a stoker-fired boiler; (2) carbon monoxide (CO)
must be monitored continuously, must be linked to an automatic ECF feed
cutoff system, and must not exceed 100 ppmv on an hourly rolling average
(corrected to 7% oxygen); (3) the boiler must fire at least 50% primary
fuel on a heat input or volume basis, whichever results in a higher
volume of primary fuel, and the primary fuel must be fossil fuel or tall
oil with a heating value not less than 8,000 Btu/lb; (4) the boiler load
must be 40% or greater; (5) the ECF must have an as-fired heating value
of 8,000 Btu/lb or greater; (6) ECF must be fired into the primary fuel
flame zone; (7) the ECF firing system must provide proper atomization;
and (8) if the boiler is equipped with an electrostatic precipitator
(ESP) or fabric filter (FF) and does not fire coal as the primary fuel,
the combustion gas temperature at the inlet to the ESP or FF must be
continuously monitored, must be linked to the automatic ECF feed cutoff
system, and must not exceed 400°F on an hourly rolling average.  These
conditions are consistent with oil-fired industrial boiler design and
operating conditions that ensure good combustion (and post-combustion
control of dioxin/furan) and ensure that emissions from burning ECF are
comparable to fuel oil emissions.  In addition, as discussed in the
previous section, such emissions would be at levels which are protective
of human health and the environment.

The boiler design and operating conditions that ensure a hot, stable
flame and good combustion of ECF (i.e., all of the conditions, except
the condition to minimize post-combustion formation of dioxin/furan by
limiting the gas temperature at the inlet to the ESP or FF) derive from
extensive testing that EPA conducted in the mid-1980’s to identify
design and operating parameters that affect the combustion of toxic
hazardous organic compounds in waste fuels fired as supplementary fuel
in boilers.  See 52 FR at 16995-96 (May 6, 1987).  EPA used the results
of that testing to identify design and operating conditions that would
ensure that waste fuel is properly atomized and fired into a hot, stable
flame to ensure destruction of toxic hazardous organics in the waste
fuel to trace levels and to minimize formation of products of incomplete
combustion (PICs) to levels that would not pose a hazard to human health
or the environment.

Those operating conditions also reflect typical operations for an
oil-fired industrial boiler operating under good combustion conditions:
(1) as discussed below, CO levels below 100 ppmv are typically achieved
by oil-fired industrial boilers; (2) the oil fuel provides a hot, stable
flame; and (3) boilers generally operate at loads greater than 40% and
can experience poor combustion conditions at lower loads.  The design
conditions—the boiler must be a watertube steam boiler that is not
stoker-fired—also reflect industrial boiler designs that help ensure
optimum combustion efficiency.  See discussion below in Section B.1.

A.  Why Isn’t a DRE Performance Test a Critical Requirement to Ensure
Good Combustion Conditions?

EPA concluded from the boiler testing discussed above that:  (1) boilers
cofiring hazardous waste fuels with fossil fuels where the hazardous
waste provides less than 50 percent of the boiler's fuel requirements
can achieve 99.99 percent destruction and removal efficiency (DRE) of
POHCs (principal organic hazardous constituents) under a wide range of
operating conditions (e.g., load changes, waste feed rate changes,
excess air rate changes); (2) when boilers are operated at high
combustion efficiency, as evidenced by flue gas carbon monoxide (CO)
levels of less than 100 ppmv, DRE exceeds 99.99 percent; (3) boilers
clearly operating under poor combustion conditions, as evidenced, for
example, by smoke emissions, still achieved 99.99 percent DRE: (4)
emissions of PICs appeared generally to increase as combustion
efficiency decreased as evidenced by increased flue gas CO levels; and
(5) emission of total unburned hydrocarbons (i.e., quantified Part 261,
Appendix VIII pollutants, as well as unburned POHCs and other unburned
organic compounds) may increase as combustion efficiency decreases as
evidenced by an increase in flue gas CO levels.  See 52 FR at 16995.

	These results confirm that a 99.99% DRE regulatory requirement (coupled
with compliance with limits on operating conditions established during
the DRE performance test) has limited utility for ensuring that a
combustor operates under the good combustion conditions necessary to
destroy both toxic hazardous organics in the fuel feed and PICs to
levels that are protective of human health.  EPA has explained, however,
why a limit on carbon monoxide emissions (i.e., 100 ppmv, hourly rolling
average) is a conservative indicator of good combustion conditions for
boilers (and other combustors) that will result in destruction of both
POHCs and PICs.  See 52 FR at 16998; 70 FR at 59461-463.  Of the four
combustion failure modes that EPA has identified—total ignition
failure, partial ignition failure, combustion air failure, and rapid
quench failure—only a total ignition failure could result in low CO
and poor combustion of POHCs and PICs.   Total ignition failure could
potentially occur in a boiler if the fuel firing gun inadvertently
directed the fuel to a location in the combustion chamber away from the
flame zone—i.e., if the fuel were not fired into the flame zone.  The
other combustion failure modes result in high CO and potentially high
unburned organics:  partial ignition failure; combustion air failure;
and rapid quench failure.  Thus, it is important to ensure that waste
fuels are fired into the flame zone of a boiler when relying on CO
emission levels to ensure good combustion conditions (and that 99.99%
DRE is achieved), as proposed for ECF boilers.

B.  What Is the Rationale for the Proposed Burner Conditions?

From the discussion above, it could be argued that the only controls
needed to ensure good combustion conditions and destruction of toxic
hazardous organics in ECF would be continuous monitoring of carbon
monoxide and a requirement to fire ECF into the flame zone to avoid
total ignition failure.  Notwithstanding this view, we believe it is
appropriate to apply additional controls to help ensure that an ECF
boiler operates under the good combustion conditions typical of an
oil-fired industrial boiler given that ECF would be burned under a
conditional exclusion absent a RCRA permit and the regulatory oversight
typical for a RCRA hazardous waste combustor.  The proposed conditions
would help ensure good combustion conditions by requiring that ECF has
substantial heating value and that it is fired into a hot, stable flame.
 There are many industrial boilers that meet the design criteria (i.e.,
watertube steam boiler that is not stoker-fired) and the operating
conditions generally reflect standard operating practice.  The proposed
conditions consequently are analogous to conditions under which fuel
oil, the commercial product for which ECF substitutes, are burned.
Furthermore, more than 90% of the candidate waste fuel streams
identified by generators had heating values greater than 8,000 Btu/lb.

The rationale for each of the proposed burner conditions is discussed
below.  We specifically request comment on each of these proposed
conditions.

1.  ECF Must Be Burned in a Watertube Steam Industrial or Utility Boiler
That Is Not Stoker-Fired

	A condition of the proposed exclusion would require the ECF burner to
be a watertube steam boiler that does not fire fuels using a stoker or
spreader-stoker feed system.  ECF also must be burned in a boiler rather
than in an industrial furnace, such as a cement kiln, because the Agency
conducted nonsteady-state emissions tests (as part of the boiler testing
program discussed above) to identify the parameters that affect
combustion efficiency only for boilers.  Industrial furnaces have a
primary purpose other than burning fuels most efficiently and we have
not determined the operating conditions that would ensure good
combustion conditions absent the regulatory oversight provided by the
RCRA hazardous waste permit program.

	The boiler must be a watertube, nonstoker boiler because there is a
greater potential for poor distribution of combustion gases and
localized cold spots in firetube and stoker boilers that can result in
poor combustion conditions.  In particular, stoker and spreader-stoker
boilers generally burn solid fuels with a relatively large particle size
on a bed, thus making even distribution of combustion air difficult.
See 56 FR at 7148.

	The boiler must be a steam boiler rather than a process heater because
process heaters can have a primary purpose other than to burn fuels
under optimum combustion conditions.  An example is a process heater
that quenches combustion gases to reduce gas temperatures to avoid
overheating a process fluid.  Such operating conditions could adversely
affect combustion efficiency by interrupting the complete combustion of
organic compounds.

	Finally, the boiler must be an industrial or utility boiler as
currently required under the comparable fuel exclusion.  See proposed
§261.38(c)(2)(i).  This would ensure that ECF is burned in boilers that
are capable of handling this type of fuel (e.g., rather than boilers at
schools, apartments, or hospitals) and that would be subject to Federal,
state, or local air emission requirements.

We request comment on whether there are other types of combustors (e.g.,
thermal oxidizer) that may be able to burn ECF under the good combustion
conditions comparable to an industrial watertube steam boiler (that is
not of stoker design).  Any suggestions for other types of combustors
must include supporting information in order for the Agency to be able
to consider it for final action.

2.  CO Monitoring

A condition of the proposed exclusion would require that combustion gas
CO be monitored continuously, that the CO recordings be linked to an
automatic ECF feed cutoff system, and that CO emissions not exceed 100
ppmv on an hourly rolling average (corrected to 7% oxygen).  As
discussed above, low CO emissions, coupled with firing ECF in the
primary fuel flame zone, are the primary controls for ensuring that the
boiler is operating under good combustion conditions.

EPA has used continuous CO monitoring as an indicator of good combustion
for various types of combustors, including boilers that burn hazardous
waste and boilers that do not burn hazardous waste.  See 70 FR at
59463-64 for a discussion of using CO to control organic HAP under the
NESHAP for hazardous waste boilers, and 68 FR at 1671 for a similar
discussion in the context of the NESHAP for boilers that do not burn
hazardous waste.  We note that the NESHAP for boilers that do not burn
hazardous waste (i.e., Industrial Boiler NESHAP) requires continuous CO
monitoring only for new solid, liquid, or gas boilers with a capacity
greater than 100 MM Btu/hr.  The CO limit is 400 ppmv corrected to 3%
oxygen for oil and gas boilers and 400 ppmv corrected to 7% oxygen for
solid fuel boilers, and is based on a 30-day average.  Boilers with a
capacity in the range of 10 MM Btu/hr to 100 MM Btu/hr comply with the
CO limit based on a 3-run average during periodic performance testing.
See Table 1 to Subpart DDDDD, Part 63.  EPA did not establish a CO limit
for existing boilers that do not burn hazardous waste because:  (1) CO
monitoring was not floor control given that inadequate information was
available to conclude that 6% of the sources were equipped with CO
monitors or that 6% of the sources were subject to state standards for
CO monitoring; and (2) CO monitoring did not appear to be cost-effective
as a beyond-the-floor control technique.  For new sources where MACT
floor is based on the performance of the single best performing source
within a category or subcategory, EPA established CO monitoring
requirements based on the most stringent state standards for CO
monitoring that applied to all large boilers (i.e., greater than 10 MM
Btu/hr) in a subcategory (i.e., solid fuel, liquid, and gas boilers) and
to all fuel types burned by boilers within the subcategory (e.g., for
solid fuel boilers, coal, wood, and other biomass).

Notwithstanding the 400 ppmv CO limit (based on a 30-day average or
periodic performance testing) applicable to new industrial boilers that
do not burn hazardous waste, a 100 ppmv limit (based on an hourly
rolling average) is appropriate for ECF burners because:  (1) the
limited CO data in the Industrial Boiler NESHAP data base indicate that
oil-fired boilers, the boiler subcategory most analogous to a boiler
burning ECF, are achieving CO levels below 100 ppmv; (2) hazardous waste
fuels that are proposed to be excluded as ECF are currently burned in
boilers subject to a 100 ppmv (hourly rolling average) CO standard under
RCRA §266.104, also indicating that a CO limit of 100 ppmv is readily
achievable; and (3) a tighter CO limit for ECF than the CO limit that
applies to industrial boilers burning fossil fuels and nonhazardous
waste fuels is appropriate given the greater potential for ECF emissions
to pose a hazard to human health and the environment (i.e., it is
reasonable and appropriate to tailor the management controls that apply
to the most analogous product, fuel oil, to address the greater hazards
posed by potentially high concentrations of toxic hazardous organic
compounds in ECF).

	We similarly do not believe that periodic rather than continuous CO
monitoring would be appropriate for ECF boilers, even though periodic CO
monitoring is allowed under the Industrial Boiler NESHAP to boilers in
the size range of 10 MM Btu/hr to 100 MM Btu/hr.  As discussed above,
low CO emissions, combined with the requirement to fire ECF into the
primary fuel flame zone, is the principal indicator of good combustion
conditions.  Periodic CO monitoring would ensure good combustion
conditions only periodically—combustion conditions could deteriorate
an hour, day, or week after the periodic performance test.  Given the
potential hazards that burning ECF under poor combustion conditions can
pose compared to fossil fuels and nonhazardous waste fuels, and given
the variability in combustion characteristics that ECF may have over
time relative to the primary fuel, it is reasonable to condition the
exclusion on continuous CO monitoring.  Nonetheless, we specifically
request comment on whether periodic rather than continuous CO monitoring
should be allowed for ECF boilers in the size range of 10 MM Btu/hr to
100 MM Btu/hr, consistent with the Industrial Boiler NESHAP CO
monitoring provisions for new boilers.  Commenters should must explain
and provide supporting information why periodic monitoring is
sufficient, including how the owner or operator would ensure that the
boiler is operating under “good combustion conditions” during those
times that the boiler is not being monitored for CO in order for the
Agency to be able to consider it for final action.

	Finally, we propose to specify that the CO monitor must be linked to an
automatic ECF feed cutoff system to ensure that ECF is fired only when
the boiler is operating under good combustion conditions—when CO
levels are below 100 ppmv on an hourly rolling average.  Linking the CO
monitor to an automatic ECF feed cutoff system is appropriate given that
emissions may be neither comparable to fuel oil nor protective if the
boiler is not operating under good combustion conditions.  An automatic
feed cutoff system does not appear to be cost-prohibitive and would help
assure effective combustion.  We propose to adopt the provisions for
automatic feed cutoff systems that apply to boilers that burn hazardous
waste--§63.1206(c)(3)--and for the same reasons.  See USEPA,
“Technical Support Document for HWC MACT Standards, Volume IV:
Compliance with the HWC MACT Standards,” July 1999, Chapter 11.

3.  The Boiler Must Fire at Least 50% Primary Fuel

A condition of the proposed exclusion would require an ECF boiler to
fire at least 50% primary fuel on a heat input or volume basis,
whichever results in a higher volume of primary fuel, and the primary
fuel must be fossil fuel or tall oil with a heating value not less than
8,000 Btu/lb.  These conditions would ensure that a hot, stable flame is
provided to help ensure optimum combustion conditions.  Although a
primary fuel firing rate of 50% is at the lower end of the range of
reasonable values—50% to 75% primary fuel—that could have been
selected, we believe it is a reasonable condition because it would
ensure that the boiler is burning primarily fossil fuel (or equivalent)
and so ensures a hot, stable flame.  We also note that this condition
would be consistent with the primary fuel requirement for hazardous
waste boilers under §266.110 that elect to waive the DRE performance
standard under operating conditions that ensure optimum combustion
efficiency.

The primary fuel would be required to have a minimum heating value of
8,000 Btu/lb to reflect the low end of the range of heating values for
fossil fuels normally fired in industrial boilers.  Most coal-fired
industrial boilers burn either subbituminous coal (with heating values
ranging from 8,300-11,500 Btu/lb) or bituminous coal (with heating
values ranging from 10,500 to 14,000 Btu/lb).  Lignite, a low-rank coal
that typically has a heating value below 8,000 Btu/lb, is not commonly
burned in industrial boilers

Although we believe that the primary fuel would generally be fossil
fuel—oil, natural gas, or coal (i.e., pulverized coal burned in
suspension)--it is reasonable to allow other high-quality fuels as the
primary fuel.  Consequently, tall oil would also be allowed as a primary
fuel.  Tall oil is fuel derived from vegetable and rosin fatty acids and
has a heating value comparable to fuel oil.

We specifically request comment on whether a condition to require a
minimum of 50% primary (generally fossil) fuel is appropriate to
maintain a hot, stable flame to ensure good combustion of ECF.  Any
comments recommending an alternative minimum limit for the primary fuel
firing rate must include supporting information in order for the Agency
to be able to consider it for final action.

4.  The Boiler Load Must Be 40% or Greater

A condition of the proposed exclusion would require the ECF boiler to
operate at 40% load (i.e., the heat input at any time when ECF is fired
must be at least 40% of the maximum rated boiler heat input) or greater
to ensure a hot, stable flame.  At low loads, higher excess air rates
are used to improve fuel/air mixing.  The increased excess air rates,
however, can also cool the flame zone and even make the flame unstable
(e.g., as a candle flame flickers in a breeze), thereby increasing the
likelihood of flameout.  These conditions can result in reduced
combustion efficiency.  Although a minimum boiler load could have been
selected within the reasonable range of 25% to 40% of maximum load, we
believe it is appropriate to adopt a value at the high end of the range
to be conservative given that ECF can contain concentrations of certain
hydrocarbons and oxygenates higher than the specifications listed in
Table 1 to §261.38.  We also note that a minimum load requirement of
40% would be consistent with the requirement for hazardous waste boilers
under §266.110 that elect to waive the DRE performance standard under
operating conditions that ensure optimum combustion efficiency.

We specifically request comment on whether a condition on minimum boiler
load of 40 percent is appropriate to maintain a hot, stable flame and
thus ensure good combustion conditions.  Any comments recommending an
alternative minimum boiler load must include supporting information in
order for the Agency to be able to consider it for final action.

5.  The ECF Must Have an As-Fired Heating Value of 8,000 Btu/lb or
Greater

A condition of the proposed exclusion would require the ECF to have an
as-fired heating value of 8,000 Btu/lb or greater.  This is a reasonable
minimum heating value that could have been selected within the range of
5,000 Btu/lb to 10,000 Btu/lb because:  (1) it is the minimum heating
value of fossil fuels normally fired in industrial boilers (i.e.,
subbituminous coal); and (2) it would help ensure that a hot, stable
primary fuel flame is maintained.  We also note that more than 90% of
the candidate waste fuel streams identified by generators had heating
values greater than 8,000 Btu/lb.

	Although ECF, like comparable fuel, would need to have a heating value
of 5,000 Btu/lb as-generated (or after bona fide treatment as a
hazardous waste), it must have a minimum heating value of 8,000 Btu/lb
as-fired.  Accordingly, ECF may be blended with fuels (including
comparable fuel) other than hazardous waste to achieve an as-fired
heating value of at least 8,000 Btu/lb.  However, any fossil fuel used
to blend ECF to achieve the minimum 8,000 Btu/lb heating value
requirement could not be counted to achieve the proposed condition that
the boiler must have a minimum firing rate of 50% primary fuel.

We specifically request comment on whether a condition to require that
ECF have an as-fired heating value of 8,000 Btu/lb or greater is
appropriate to help ensure that the hazardous compounds that may be
present in the ECF at high concentrations are destroyed to levels
comparable to oil-fired boiler emissions.  Any such comments on
alternative ECF heating values must include supporting information in
order for the Agency to be able to consider it for final action.

6.  ECF Must Be Fired into the Primary Fuel Flame Zone

As a condition of the proposed exclusion, ECF must be fired into the
primary fuel flame zone to avoid, potentially, total ignition
failure—a combustion failure mode characterized by poor combustion,
high emissions of unburned organic compounds, but potentially low CO
emissions.  Under this combustion failure mode, organic compounds in ECF
would not be exposed to the hot flame zone and may be simply volatilized
absent combustion.  Thus, under this failure mode, low CO emissions may
not be indicative of good combustion conditions.

As a practical matter, firing waste fuels (or any fuels) directly into
the flame zone of the boiler is standard operating practice.  Directing
the fuel burner in a direction that avoided the flame zone would
normally occur only inadvertently.  Nonetheless, we believe it is
prudent to propose this condition to highlight its importance in
achieving good combustion conditions.

We specifically request comment on whether a condition to require that
ECF be fired into the primary fuel flame zone is appropriate to help
ensure that the hazardous compounds that may be present in the ECF at
high concentrations are destroyed to levels comparable to oil-fired
boiler emissions.  Any such comments must include supporting information
in order for the Agency to be able to consider it for final action.

7.  The ECF Firing System Must Provide Proper Atomization

As a condition of the proposed exclusion, the ECF firing system must
provide proper atomization to ensure that the ECF droplets are not too
large for optimum volatilization.  An organic compound must be vaporized
and mixed with air before combustion can occur.  The quicker ECF and its
constituents are vaporized and the more completely the volatilized
compounds are mixed with air, the more rapid and efficient the
combustion and destruction of organic constituents.  Firing systems that
atomize liquid fuels to form small droplets increase the rate of
vaporization by providing a larger surface area per volume of fuel to
absorb heat from the flame.

We are proposing to allow the use of virtually all atomization systems
commonly used to fire liquid fuels.  We are, however, proposing to
restrict the maximum size of solids that may be present in liquid fuels
that meet the viscosity specification of 50 cSt—the as-fired ECF must
pass through a 200 mesh screen.  This would ensure that the appropriate
droplet size is achieved (to ensure volatilization and destruction of
organic compounds) and minimize plugging of the firing nozzle.  The
acceptable atomization systems are air, steam, mechanical, or rotary cup
atomization systems.

a. Air or steam atomization.  Air or steam atomization systems use air
or steam to break up the fuel into small droplets.  Under ordinary
operations, high pressure steam or air provided at 30 to 150 psig
produces much smaller droplets than other atomization systems.  Because
of the cost of providing high pressure air and where steam is not
readily available, low pressure (1-5 psig) burners are sometimes used.

b. Mechanical atomization.  Mechanical atomizers break up the fuel into
small droplets by forcing it through a small, fixed orifice.  A strong
cyclonic or whirling velocity is imparted to the fuel before it is
released through the orifice.  Combustion air is provided around the
periphery of the conical spray of fuel.  The combination of combustion
air introduced tangentially into the burner and the action of the
swirling fuel produces effective atomization.

The size of the droplets produced by mechanical atomization is a
function principally of the fuel viscosity and the fuel pressure at the
atomizing nozzle.  The pressure required to produce a droplet size
conducive to optimum combustion efficiency depends on the volatility of
the fuel.  Highly volatile materials can volatilize rapidly, even from
larger droplets, and, thus, can be fired at pressures of 75 to 150 psig.
 Less volatile fuels may require an atomization pressure as high as
1,000 psig to form droplets small enough to rapidly volatilize.

Given that fuel pressure is an important factor in determining droplet
size, we considered whether it would be appropriate to propose to limit
the minimum fuel pressure as a condition of the exclusion.  Optimum fuel
pressure to produce an optimum droplet size, however, is a function of
fuel volatility and fuel/air mixing.  Thus, it is not practicable to
propose specific limits on minimum fuel pressure.  Rather, we are
proposing that the boiler owner or operator be required to maintain fuel
pressure within the atomization system design range considering the
viscosity and volatility of the waste fuel, the fuel/air mixing system,
and other appropriate parameters.  This approach would allow the
atomization system manufacturer or designer (e.g., if designed and
fabricated on-site) the necessary flexibility to determine an acceptable
fuel pressure considering the specifics of the situation.  If fuel
pressure is not maintained at appropriate levels to ensure small droplet
size and optimum combustion efficiency or, if for any other reason the
boiler does not achieve maximum combustion efficiency, the boiler may
not be able to achieve CO levels below 100 ppmv.

c. Rotary cup atomization.  The rotary cup atomizer uses centrifugal
force to break up the fuel into droplets.  It consists of an open cup
mounted on a hollow shaft.  The fuel is pumped at low pressure through
the hollow shaft to the cup which is rotating at several thousand
revolutions per minute. A thin film of the fuel is centrifugally torn
from the tip of the cup.  As centrifugal force drives the fuel off the
cup, combustion air is admitted in a rotation counter to the direction
of the cup.  This counter motion of the air breaks up the conical sheets
of fuel into droplets and provides turbulence for mixing the droplets
with air.

Rotary cup atomizers are typically used on smaller boilers (e.g., less
than 30 MM Btu/hr heat input) because the maximum capacity of the
largest unit is about 1,400 pounds of fuel per hour.  In addition,
rotary cup atomizers are not often installed on new boilers because it
is difficult to achieve optimum fuel/air mixing over a wide range of
fuel flow rates.  Rotary cup atomizers are used because they are
relatively inexpensive, they can handle fuels with relative high
viscosities ranging up to 40 to 72 cSt, and they are relatively
insensitive to solid impurities in the fuel and can handle waste fuels
with solids that can pass through a 34 to 100 mesh screen.

Droplet size is related primarily to the viscosity and flow rate of the
fuel and rotational speed of the cup.  Resulting combustion efficiency
is related to volatility of the fuel and fuel/air mixing.  Although it
is impracticable to control these variables in a regulatory context,
manufacturers and boiler owners and operators have ample experience with
rotary cup atomizers to design units that achieve efficient combustion.
Thus, we are proposing that owners and operators demonstrate that the
as-fired fuel has a volatility within the design parameters of the
firing system and limit fuel flow rates consistent with the design
parameters of the firing system.  As discussed above, relative to
mechanical atomization systems, if, in fact, the device does not produce
droplet sizes and fuel/air ratios conducive to maintaining high
combustion efficiency, the boiler may not be able to achieve CO levels
below 100 ppmv.

We specifically request comment on whether these conditions for
atomization of ECF are appropriate to help ensure that the hazardous
compounds that may be present in the ECF at high concentrations are
destroyed to levels comparable to oil-fired boiler emissions.  Any such
comments must include supporting information in order for the Agency to
be able to consider it for final action.

8.  Dioxin/Furan Controls for Boilers Equipped with an ESP or FF

If a boiler is equipped with an electrostatic precipitator (ESP) or
fabric filter (FF) and does not fire coal as the primary fuel, we are
proposing that the combustion gas temperature at the inlet to the ESP or
FF be continuously monitored, be linked to the automatic ECF feed cutoff
system, and not exceed 400°F on an hourly rolling average.  These
proposed conditions would ensure that the post-combustion, heterogeneous
surface-catalyzed formation of dioxin/furan in an ESP or FF is minimized
so that emissions from burning ECF remain at least comparable to those
from burning fossil fuels and remain at levels that are protective of
human health and the environment.

We are basing these proposed conditions on information and data gathered
from the recently promulgated NESHAP standards for hazardous waste
combustors.  See 70 FR 59402.  Specifically, we have determined that the
surface-catalyzed formation of dioxin/furan across an ESP or FF can be
significant when gas temperatures exceed 400°F.  When gas temperatures
are below 400°F (and the combustor is operating under good combustion
conditions as evidenced by CO below 100 ppmv), however, dioxin/furan
emissions are generally below 0.40 ng TEQ/dscm, the emission standard
for most hazardous waste combustors.

Boilers burning coal as the primary fuel would not be required to
monitor combustion gas temperature at the inlet to an ESP or FF as a
condition of the exclusion, however.  We determined during development
of the NESHAP for coal-fired boilers that burn hazardous waste that
sulfur contributed by the coal is a dominant control mechanism because
the sulfur inhibits formation of dioxin/furan.  Please note, however,
that a peer reviewer questioned whether the low sulfur coal that some
ECF boilers may burn would also inhibit formation of dioxin/furan.  We
believe that low sulfur coals would also inhibit formation of
dioxin/furan (and, thus, a condition to limit the gas temperature at the
inlet to the ESP or FF would not be needed), but request comment and
supporting information on opposing views.  See discussion in Section VII
below.

We are further proposing an hourly averaging period for the temperature
limit, rather than a longer averaging period, because there is a
nonlinear relationship between gas temperature at the ESP or FF and
dioxin/furan emissions.  Consequently, a longer averaging period would
allow higher temperatures to be offset by lower temperatures, even
though dioxin/furan emissions at the higher temperatures could be
exponentially higher than emissions at the lower temperatures, and,
thus, average dioxin/furan emissions would be substantially higher than
if temperatures had been maintained at the average temperature.

We also believe that there are factors other than high gas temperature
at the inlet to an ESP or FF that may contribute to the post-combustion
formation of dioxin/furan in boilers, but these situations would not
occur for boilers burning ECF under the proposed conditions.  For
example, we have dioxin/furan emissions data for nine three-run test
conditions for eight boilers burning liquid hazardous waste fuel and
equipped with wet scrubbers, and two of the boilers have emissions
exceeding 0.40 ng TEQ/dscm.  Although the wet scrubbers on these boilers
preclude surface-catalyzed dioxin/furan formation across the emission
control device, the boilers nonetheless have high dioxin/furan
emissions—1.4 ng TEQ/dscm and 0.44 ng TEQ/dscm.  We note, however,
that both of these boilers are firetube boilers and one burns waste fuel
containing 60% by weight chlorine.  Firetube boilers would not be
allowed to burn ECF under the conditions proposed today for reasons
discussed above and, in addition, the chlorine level in the waste fuel
for one of the boilers is orders of magnitude higher than the
specification for chlorine in Table 1 to §261.38.  It is speculated
that the higher tube surface to combustion gas volume ratio for a
firetube boiler compared to a watertube boiler may increase the
possibility of combustion gas flow over particulate matter that has
adhered to the tubes within the 400-750°F temperature window, which is
conducive to surface-catalyzed formation of dioxin/furan.

We also have dioxin/furan emissions data for 11 three-run test
conditions for six different boilers that burn hazardous waste and that
are equipped with an ESP or FF.  Gas temperatures at the ESP or FF were
generally below 400 F.  Only two test conditions (from two boilers)
were above 0.4 ng TEQ/dscm.  One boiler (which would be ineligible to
burn ECF because it is a firetube boiler) had emissions of 0.66
ngTEQ/dscm during one test condition.  This unit burns mixed waste with
levels of chlorine and metals above the specifications in Table 1 to
§261.38.  The second boiler (a watertube boiler), however, had average
emissions of 2.4 ng TEQ/dscm.  Although the FF for this boiler was
operated slightly above 400°F, we note that this boiler burned waste
fuel containing nickel at levels orders of magnitude higher than the
specification identified in Table 1 to §261.38.  Nickel, as well as
copper and iron, have been suggested to be responsible for the catalytic
reactions that lead to post-combustion formation of dioxin/furan.

	Therefore, based on the data described above, we believe that the
scenarios that resulted in high dioxin/furan emissions when burning
hazardous waste fuels would not occur for ECF boilers and that a
proposed condition that would limit the gas temperatures at the inlet to
a dry particulate matter control device to 400°F should control
dioxin/furan emissions generally to below 0.40 ng TEQ/dscm.  Moreover,
we note that we have dioxin/furan emissions data for 38 three-run test
conditions representing 32 different boilers burning hazardous waste
fuel and not equipped with an emissions control device where the test
condition average emissions were quite low—below 0.10 ng TEQ/dscm.  In
addition, we have dioxin/furan emissions data for 15 runs for oil-fired
industrial boilers (i.e., not burning hazardous waste), and the average
emissions were 0.013 ng TEQ/dscm and the maximum emissions were 0.042 ng
TEQ/dscm.  This is further information indicating that dioxin/furan
emissions from boilers burning ECF under the proposed conditions should
be quite low.

III. What Restrictions Would Apply to Particular Hydrocarbons and
Oxygenates?

The toxicity, persistence and bioaccumulation potential for the 37
hydrocarbons and oxygenates for which specifications have been
established in Table 1 to §261.38 varies over a wide range.  In
addition, we acknowledge that when ECF with potentially higher
concentrations of certain hydrocarbons and oxygenates than fuel oil is
burned, even under good combustion conditions, emissions of toxic
hazardous organics maybe somewhat higher than those from burning fossil
fuel because combustion is generally a percent-reduction process.
Therefore, to ensure that the emissions from burning ECF as a fuel under
the conditions proposed today remain protective, we propose to retain
the specifications for compounds that can pose a high
hazard—naphthalene and PAHs—and to restrict the firing rate of ECF
containing concentrations of compounds that can pose a lower, but
substantial hazard—benzene and acrolein.  See Safe Food and
Fertilizers, 353 F. 3d at 1271 (exclusion from the definition of solid
waste can be justified by low risk posed by the recycling practice).

We explain below the rationale for the approach we use to categorize the
37 hydrocarbons and oxygenates for which specifications are established
in Table 1 to §261.38, according to their relative hazard to human
health and the environment.

A.  What is the Rationale for the Relative Hazard Characterization
Scheme?

We categorized the 37 hydrocarbons and oxygenates for which
specifications have been established in Table 1 to §261.38 as to their
relative hazard.  We assigned the highest hazard constituents to
Category A, the constituents that pose intermediate hazard to Category
B, and the other constituents to Category C.  As mentioned above, we are
proposing to retain the specifications for the Category A constituents,
restrict the feedrate of the Category B constituents, and not apply the
specifications in Table 1 to the Category C constituents.  We discuss
below the procedure for categorizing the constituents.

First, we We used the Waste Minimization Prioritization Tool (WMPT)to
rank the 37 hydrocarbons and oxygenates for which specifications have
been established in Table 1 to §261.38.  The WMPT is a peer-reviewed
methodology which provides a screening-level assessment of potential
chronic (i.e., long-term) risks to human health and the environment,
considering the chemicals’ toxicity, persistence and bioaccumulation
potential.

	The WMPT scoring method produces chemical-specific scores for a
screening-level risk-based ranking of chemicals.  The scoring method was
designed to generate an overall chemical score that reflects the
potential of a chemical to pose risk to either human health or
ecological systems.  A measure of human health concern is derived,
consistent with the risk assessment paradigm, by jointly assessing the
chemical’s human toxicity and potential for exposure.  Similarly, a
measure of the ecological concern is derived by jointly assessing the
chemical’s ecological toxicity and potential for exposure.  The WMPT
uses a small number of relatively simple measures to represent the
toxicity (e.g., oral Cancer Slope Factor) and exposure potential (e.g.,
Bioaccumulation Factor) of each chemical, consistent with a
screening-level approach and with other systems of this type.

We then applied the procedures the Agency used to develop the Priority
Chemicals List from the WMPT scoring.  Thus, we assigned constituents
that scored an eight or nine to the high hazard category—Category A.

Next, we considered whether any of the remaining constituents may pose a
particular hazard that may not have been evident from the WMPT scoring.
We first identified constituents that had WMPT human toxicity scores
based on inhalation as the driving exposure pathway.  This is an
appropriate screening criterion given that the inhalation pathway is
particularly important for evaluating the hazard posed by air emissions.
 For such constituents, we then determined whether they posed a
relatively high human toxicity hazard.  If so, we assigned the
constituent to hazard Category B.

We assigned all other constituents to hazard Category C.

B.  What Are the Results of the Relative Hazard Ranking?

We assigned 11 constituents to Category A—the high hazard
constituents.  These are constituents that had WMPT scores of eight or
nine, consistent with the Agency’s procedures for identifying priority
chemicals.  Because the WMPT methodology assigns all PAHs the highest
score for any PAH, we assigned a score of nine to all PAHs.  Ten of the
11 Category A constituents are PAHs.  The only Category A constituent
that is not a PAH, but that scored an eight or nine, was naphthalene.

In evaluating constituents to assign to hazard Category B, we identified
three constituents that have WMPT human toxicity scores based on
inhalation as the driving exposure pathway:  benzene, acrolein, and
phenol.

Benzene is a known human carcinogen via the inhalation exposure pathway.
 There are some chemicals with sufficiently robust toxicologic databases
that the Agency not only generates a carcinogenic slope factor, but also
designates them “known human carcinogens.”  We also note that EPA
has acknowledged the health concerns associated with benzene emissions
and has proposed regulations that would reduce benzene emissions from
mobile sources by means including lowering the benzene content of
gasoline.  Consequently, we believe it is reasonable to assign benzene
to Category B to restrict the feedrate (and thus emissions) of this
compound.

Acrolein has a WMPT human toxicity score of three because it has very
high inhalation toxicity—its RfC is 0.00002 mg/m3.  Acrolein did not
have a higher aggregate WMPT score because it had a low bioaccumulation
score.  Nonetheless, exposure via inhalation is of particular importance
in the context of assessing the hazard posed by emissions from burning
ECF.

We did not assign phenol to Category B because it has significantly
lower toxicity than benzene and acrolein.  Phenol has a WMPT human
toxicity score of two, rather than the highest score of three.  Further,
phenol is not known to be a carcinogen.  EPA has classified phenol as a
Group D carcinogen—not classifiable as to human carcinogenicity, based
on a lack of data concerning carcinogenic effects in humans and animals.
 In addition, phenol, with a RfC of 0.2 mg/m3, has a noncancer toxicity
that is orders of magnitude lower than acrolein.  Consequently, we do
not believe that phenol should be assigned to hazard Category B even
though its WMPT human toxicity score is based on the inhalation pathway.

Based on our analysis, we are proposing to retain the existing
specifications currently in Table 1 to §261.38 for polycyclic aromatic
hydrocarbons (PAHs) and naphthalene.  Based on WMPT rankings, these
compounds potentially pose substantially higher hazard than the other
hydrocarbons and oxygenates, and thus, may increase the risk to human
health and the environment when burning ECF, even under the proposed
conditions.  PAHs demonstrate high toxicity, and a tendency to both
persist in the environment and bioaccumulate.  In addition, PAHs are
common combustion byproducts, and are very difficult to thermally
destroy.  Naphthalene is likewise demonstrates high toxicity, and a
tendency to both persist in the environment and bioaccumulate.
Naphthalene is also very difficult to destroy thermally, is even more
toxic for ecological endpoints than for humans, and is commonly found in
stack gas emissions.  (See Section VII where we address a peer review
comment regarding grouping of PAHs as high hazard compounds and
classifying naphthalene as a high hazard compound.)

In addition, we are also proposing to restrict the firing rate for ECF
that contains benzene and acrolein at concentrations exceeding 2% by
weight.  Although these compounds pose a somewhat lower hazard than the
PAHs and naphthalene, they still pose a higher hazard than the remaining
hydrocarbons and oxygenates, and thus, likewise may increase the risk to
human health and the environment when burning ECF.  Benzene is a known
human carcinogen, very persistent in the environment, a PAH precursor,
and very difficult to thermally destroy.  Acrolein has very high
inhalation toxicity and ambient levels of acrolein are already at or
above the hazard quotient in many urban areas.  For the remaining 24
hydrocarbons and oxygenates that are listed in Table 1 to §261.38, we
are proposing not to apply any specification.

C.  What Firing Rate Restrictions Would Apply to Benzene and Acrolein?

As discussed  mentioned above, we believe that benzene and acrolein pose
a lower hazard than PAHs and naphthalene, but a greater hazard than the
other hydrocarbons and oxygenates for which the specifications would not
apply for ECF.  Accordingly, we propose to restrict the firing rate of
ECF that has benzene or acrolein concentrations exceeding 2% by weight,
as-fired, to 25% of the heat input to the boiler (on a heat input or
volume input basis, which ever results in the lower volume of ECF).

This ECF firing rate restriction would reduce the feedrate of benzene
and acrolein and thus ensure that emissions of these compounds remain at
levels comparable to emissions from burning fuel oil in industrial
boilers and protective of human health and the environment.  Absent this
firing rate restriction, ECF with high concentrations of benzene or
acrolein could be fired at a 50% firing rate--the remaining 50% of the
fuel must be primary fossil fuel or equivalent.  Thus, the 25% firing
rate restriction would reduce the feedrate of benzene and acrolein by
half.

	We selected a 25% firing rate restriction because it is in the middle
of the range of values that could have been reasonably considered—10%
to 40%--given that the maximum firing rate for any ECF is 50%.  We
selected a 2% or greater benzene concentration as the criterion for
applying the firing rate restriction because selecting a lower
concentration cutpoint would restrict the composite benzene
concentration in total fuels to levels lower than would be allowed if
comparable fuel were burned as 100% of the boiler fuel.  Specifically,
we assumed that comparable fuel would generally have a heating value of
at least 10,000 Btu/lb if it were to comprise 100% of the boiler’s
fuel.  The comparable fuel specification would allow a benzene
concentration of 4,100 mg/kg (or 0.41%) for a 10,000 Btu/lb fuel.  We
further assumed the upper range of heating values for the comparable
fuel would be 18,000 Btu/lb.  At that heating value, the comparable fuel
could contain 7,400 mg/kg (or 0.74%) benzene.

We then determined the benzene concentration in ECF fired at a 25%
firing rate as a supplement to fuel oil that would result in a composite
fuel benzene concentration equivalent to the levels allowed if existing
comparable fuel were 100% of the boiler fuel.  Virtually all of the
benzene would be contributed by the ECF because fuel oil contains
negligible benzene.  At a 25% firing rate, the benzene concentration in
a 10,000 Btu/lb ECF would need to exceed 1.6% for the benzene
concentration in the composite fuels (i.e., ECF and fuel oil) to exceed
4,100 mg/kg, the benzene concentration in the fuel if 10,000 Btu/lb
comparable fuel were fired as the sole fuel burned.  Similarly, at a 25%
firing rate, the benzene concentration in an 18,000 Btu/lb ECF would
need to exceed 3% for the benzene concentration in the composite fuels
to exceed 7,400 mg/kg, the benzene concentration in the fuel if 18,000
Btu/lb comparable fuel were fired as the sole fuel burned.

Consequently, the reasonable range of ECF benzene concentrations for
selecting the cutpoint to apply the 25% firing rate restriction is 1.6%
to 3%.  We are proposing a cutpoint of 2% because it generally
correlates to the average heating value of waste fuels—11,000 Btu/lb.

	We then considered what cutpoint we should propose for acrolein.  We
are proposing a 2% concentration cutpoint for acrolein as well because:
(1) acrolein poses hazards similar to benzene and there is no basis for
being more or less stringent on the allowable composite fuel
concentrations; and (2) a 2% cutpoint would not control acrolein in ECF
more stringently than it is controlled in comparable fuel (i.e., ECF
fired at a 25% firing rate as a supplement to fuel oil and with an
acrolein concentration of 2% would not result in a composite fuel
acrolein concentration lower than that allowed if the boiler burned 100%
existing comparable fuel at the maximum allowable acrolein
concentration).

We specifically request comment on whether ECF firing rate restrictions
are warranted for benzene and acrolein, and if so, whether the proposed
restrictions are appropriate.  Any such comment must include an
appropriate rationale and supporting information in order for the Agency
to be able to consider it for final action.

IV.  What Conditions Would Apply to Storage of ECF?

A.  What Are the Proposed Storage Conditions?

The proposed exclusion for ECF would also be conditioned on meeting the
storage controls applicable to the closest analogous raw
material/product--fuel oil--plus a few additional controls considered
appropriate to minimize the potential for releases to the environment.
The additional controls would include “engineered” secondary
containment and fugitive air emission controls.

 Although we are proposing generally to apply storage controls
applicable to the closest analogous raw material/product – fuel oil,
the exclusion would be conditioned on more substantial “engineered”
secondary containment than several of the permissible secondary
containment methods for oil under the Spill Prevention, Control, and
Countermeasure (SPCC) provisions.   Examples of SPCC secondary
containment provisions applicable to oil include the use of dikes,
berms, retaining walls, spill diversion ponds and sorbent materials.
We are proposing to apply a more substantial “engineered” secondary
containment condition, such as double-walled tanks because we believe it
important that such secondary containment address potential releases to
groundwater.  Today’s proposed controls on air releases are based on
those applicable to another comparable product, organic liquids at the
chemical plants which often generate ECF.

These controls are appropriate considering that ECF can contain higher
concentrations of certain toxic hazardous, volatile hydrocarbons and
oxygenates than fuel oil, and so though product-like, is not precisely
analogous.  Consequently, ECF has a higher potential for releases to the
environment and a higher potential for those releases to cause
environmental harm.  Therefore, we are proposing storage and
recordkeeping controls to ensure that ECF is not managed so as to become
“part of the waste disposal problem”.  American Mining Congress v.
EPA, 907 F. 2d 1179, 1186 (D.C. Cir. 1990).

We are also proposing that ECF be stored only in tanks (including USTs),
tank cars, and tank trucks.  ECF could not be stored in other containers
(e.g., portable devices, such as 55 gallon drums) because: (1) we
believe that ECF would be generated in quantities that would make
storage in portable devices other than tank cars and tank trucks
impractical; and (2) providing conditions to ensure adequate monitoring,
inspections and air emission controls for storage in other containers
would unnecessarily complicate the rule.  Nonetheless, we request
comment on whether ECF would likely be stored in vessels other than
tanks, tank cars and tank trucks (e.g., drums positioned to collect
process drippage that is eventually consolidated with ECF in acceptable
tank, tank car, or tank truck).  If so, and if a final rule were to
allow storage in containers other than tank cars and tank trucks, we
would subject those units to management conditions similar to those that
apply to hazardous waste containers under subpart I, Part 265, control
releases.

1.  Tank Systems, Tank Cars and Tank Trucks

a.  SPCC Discharge Prevention Requirements.   For ECF tank systems, tank
cars, and tank trucks, we are proposing to condition the exclusion on
meeting certain of the discharge prevention provisions which apply to
fuel oil, or are adapted therefrom.  These are from the Spill
Prevention, Control, and Countermeasure (SPCC) provisions under 40 CFR
Part 112 that apply to petroleum oils managed at onshore facilities.
ECF generators and burners would comply with these conditions, as
adopted under §261.38(c)(1)(iii), as though ECF met the definition of
oil under §112.2. These adopted SPCC provisions would apply to all
owners and operators of ECF tanks with a capacity greater than 55
gallons.

The SPCC requirements under Part 112 include both discharge prevention
requirements and requirements to ensure effective responses to
discharges.  The discharge prevention requirements for onshore petroleum
oil tanks are implemented under a SPCC Plan and associated requirements
under §§112.1 through 112.8, and the discharge response requirements
are implemented under a Facility Response Plan (FRP) and associated
requirements under §§112.20 and 112.21.  We propose to adopt specific
provisions of the discharge prevention requirements—the SPCC
Plan—under §§112.3, 112.5, 112.7, and 112.8 only.  We are not
proposing to adopt the FRP and associated requirements, as discussed
below in Section IV.A.1.c.  In lieu of the FRP requirements, we are
proposing to adopt more appropriate provisions that apply to hazardous
waste tank systems and that achieve the same objective as the FRP
requirements—specifying proactive measures to respond to a release of
ECF.

We propose to adopt the following SPCC Plan requirements under
§261.38(c)(1)(iii) to prevent ECF releases from tank systems:

Section 112.2, Definitions.

Sections 112.3(d) and 112.3(e), Requirements to Prepare and Implement an
SPCC Plan.  Paragraph (d) requires that a licensed Professional Engineer
must review and certify the Plan, and paragraph (e) requires that a copy
of the Plan must be maintained at the facility and be available to the
Regional Administrator for on-site review.  We are not adopting
paragraphs (a), (b), (c), (f), or (g), which pertain to compliance dates
for plan preparation and implementation and self-certification of the
plan.  Because the ECF exclusion is optional and conditional, we are
proposing that all conditions in §261.38 must be met before ECF can be
managed under the conditional exclusion being proposed today.  Therefore
we are not adopting any of the compliance dates provided in the SPCC
regulations.  Also, we propose not to allow self-certification of Plans
in lieu of certification by a Professional Engineer, as allowed under
§112.6, for those facilities with an aggregate aboveground tank
capacity of 10,000 gallons or less, a provision the Agency recently
promulgated.  We are proposing not to adopt §112.6 because of the
greater hazard that a release of ECF may pose.  We do not view
certification of the Plan by a Professional Engineer as an unreasonable
burden, and believe that the value added to ensure that the Plan is
complete, accurate, and appropriate to prevent releases is warranted
given the hazards that ECF may pose.  A more important consideration is
that we do not believe that facilities with ECF tanks would meet the
primary eligibility criterion for self-certification:  the aggregate oil
and ECF tank capacity must be less than 10,000 gallons.  Therefore, this
provision would add complexity and burden for States and EPA in
implementation and enforcement with little or no off-setting benefits.
Nonetheless, we specifically request comment on whether there may be
facilities that store ECF in tanks that could meet the eligibility
criterion and whether self-certification of the SPCC Plan would be
appropriate.

Sections 112.5(a) and 112.5(b), Amendment of SPCC Plan by Owners or
Operators.  This section requires that the Plan be amended by the owner
or operator in accordance with the general requirements in §112.7 when
there is a change in the facility design, construction, operation, or
maintenance that materially affects its potential for a discharge.  This
section also states that owners or operators must complete a review and
evaluation of the SPCC Plan at least once every five years from the date
the facility becomes subject to this part, and that any technical
amendments to the Plan must be certified by a Professional Engineer.  We
propose to adopt paragraphs (a) and (b), but not paragraph (c).
Paragraph (c) requires certification of technical amendments to the Plan
and references §112.6 which allows self-certification in lieu of
certification by a Professional Engineer.  Given that we propose not to
adopt §112.6 as discussed above, we propose a condition that would
require technical amendments to be certified by a Professional Engineer.

Section 112.7, General Requirements for Spill Prevention, Control, and
Countermeasure Plans.  We propose to adopt §112.7, except for paragraph
(c) secondary containment, paragraph (d) alternative requirements in
lieu of secondary containment, and paragraph (k) alternative
requirements in lieu of secondary containment for qualified oil-filled
operational equipment.  These paragraphs would not be applicable because
they pertain to secondary containment which we propose to require under
separate conditions.  See discussion below.  The §112.7 conditions we
are proposing to adopt are paragraph (a) which requires a discussion of
the facility’s conformance with the requirements included in §112.7,
and development of the Plan; paragraph (b) which requires a prediction
of the direction, rate of flow and total quantity of material which
could be discharged when experience indicates a potential for equipment
failure, overflow, rupture or leakage; paragraph (e) which addresses
conducting inspections and tests and keeping records; paragraph (f)
which addresses personnel, training, and discharge prevention
procedures; paragraph (g) which addresses security requirements;
paragraph (h) which addresses facility tank car and tank truck
loading/unloading rack requirements; paragraph (i) which requires a
brittle fracture evaluation if a tank undergoes a change in service that
might affect the risk of a discharge; and paragraph (j) which states
that the Plan must include a complete discussion of conformance with the
requirements in this part, as well as applicable more stringent State
rules, regulations and guidelines.

Section 112.8, Spill Prevention, Control, and Countermeasure Plan
Requirements for Onshore Facilities (excluding production facilities).
We are proposing to adopt §112.8, except for:  paragraph (b), facility
drainage; paragraph (c)(2), secondary containment for bulk storage
containers; paragraph (c)(9), prevention of releases from effluent
treatment facilities; and paragraph (c)(11), secondary containment for
mobile and portable containers.  These provisions are not warranted
because we are proposing separate conditions for secondary containment,
as discussed below.  The conditions we are proposing to adopt from this
section are paragraph (a) which states that the owner or operator meet
the general requirements for the Plan listed under §112.7, and the
specific discharge prevention and containment procedures listed in this
section; paragraph (c)(1) which states that a tank not be used for
storage unless its material and construction are appropriate; paragraph
(c)(3) which addresses the drainage of uncontaminated rainwater or
effluent bypassing the facility treatment system; paragraph (c)(4) which
states that any completely buried metallic storage tank installed on or
after January 10, 1974 be protected from corrosion and regularly leak
test such storage tanks; paragraph (c)(5) which states that partially
buried or bunkered metallic tanks not be used for storage unless you
protect the buried section of the tank from corrosion; paragraph (c)(6)
which states that each aboveground tank be tested for integrity on a
regular schedule and whenever material repairs are made and that the
outside of the tanks be inspected frequently for signs of deterioration,
discharges, or accumulation of ECF inside diked areas; paragraph (c)(7)
which states that leakage through defective internal heating coils be
controlled by monitoring the steam return and exhaust lines for
contamination from internal heating coils that discharge into an open
watercourse, or pass the steam return or exhaust lines through a
settling tank, skimmer, or other separation or retention system;
paragraph (c)(8) which states that the tank system be engineered or
updated in accordance with good engineering practice to avoid discharges
(e.g., overfill prevention); paragraph (c)(10) which states that visible
discharges from tanks, tank cars, and tank trucks be promptly corrected;
and paragraph (d) which addresses provisions regarding facility transfer
operation, pumping, and facility process.  We are not proposing to adopt
the provision which requires that buried piping be provided with a
protective wrapping and coating only if the buried piping is installed
or replaced on or after August 16, 2002.  Rather, we propose to apply
this provision to all buried piping.  This is because ECF can pose a