United States
            Environmental Protection
            Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA 450/3-92/007(3)
June 1993
            Air
©EPA     Guidelines for MACT   PROPOSAL
            Determinations under
            Section 112(j)

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                             ABSTRACT

     Section 112(j)  of  the Clean Air Act as amended  in  1990

requires major sources  within a source category to apply  for a

Title V permit should the Environmental Protection Agency fail to

promulgate emission  standards for that source category  by the

date specified in  the regulatory schedule established through

Section 112(i) of  the Act.  The Title V permit application must

demonstrate the  major source's ability to achieve a  maximum

achievable control technology (MACT) emission limitation  for all

hazardous air pollutant emissions.  Regulations to implement

Section 112(j) will  be  published in 40 CFR Part 63,  Subpart  B.

This document provides  guidance for complying with these

regulations by identifying and evaluating control technology

options to determine the MACT emission limitation.
                                 U.S. Environmental Protection Agency
                                 Region 5, Libra."..- 'PI-12J)
                                 77 West Jackso.i • " ;.>varrt
                                 Chicago, IL 60604-3590

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                        Table of Contents
Introduction   	iv

Chapter 1.0    An overview of the MACT Determination Process.... l
               1.1  Overview of Statutory Requirements	1
               1.2  Overview of the Regulatory Requirements	4
               1.3  Administrative Review Process for
                    for New Emission Units	7
                    1.3.1 Application Process	7
                    1.3.2 Contents of Application	14

Chapter 2.0    The MACT Determination...
                    a Permitting Agency' s Perspective	16
               2.1  Criteria for the MACT Determination	16
               2.2  Compliance Provisions	20
               2.3  Available Control Technologies	23
               2.4  Approaches to the MACT Determination	25
               2.5  General Permits	28

Chapter 3.0    The MACT Analysis	30
               3.1  Overview of the MACT Analysis Process	31
               3.2  A Detailed Look at the MACT Analysis	36
               3.3  Determining the MACT-Affected Source on a
                    Case-by-Case Basis	47
               3.4  Similar Emission Units	53
               3. 5  Subcategorization	57

Chapter 4 . 0    The MACT Floor Finding	58
               4.1  Calculation of the MACT Floor	62
               4.2  Method 1- Computing the MACT floor using
                    existing State and Local Regulations	68
               4.3  Method 2 - Computing the MACT Floor using
                    Control Efficiency Ratings	73
               4.4  Method 3 - Computing the MACT Floor using
                    Emission Reduction Ratios (ERR)	77
               4.5  Exceptions to the Emission Reduction
                    Ratios	83
               4.6  Other Methods to Compute
                    the MACT Floor	84

Chapter 5.0    Costs, Non-Air Quality Health and Environmental
               Impacts and Energy Requirements	79
               5.1  Costs Impacts	81
               5.2  Environmental Impacts	84
               5.3  Energy Requirements	86

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                                                               ,88
Chapter 6.0    Information Sources	


References     	

Appendix A     Examples of MACT Analyses	A-l

Appendix B     Forum of Anticipated Questions	B-l

Appendix C     Definitions	c~1

Appendix D     List of Major Source Categories	D-l
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                         LIST OF FIGURES
Figure 1  Example Notice of MACT Approval	10


Figure 2  Three Tiers to the MACT Analysis	32


Figure 3  Acceptable Methods for Determining
          the MACT Floor	62


Figure 4  Using State or Local Air Pollution Regulations to
          compute the MACT Floor	69


Figure 5  Analysis of State Regulations
          for Emission Unit X	71


Figure 6  Using Control Efficiency Ratings
          to Compute teh MACT Floor	74


Figure 7  Using Emission Reduction Ratios
          to Compute the MACT Floor	78
                               111

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                          Introduction
     This guidance document is designed to clarify the statutory

and regulatory requirements for MACT determinations as required

by Section 112(j)  of the Clean Air Act (the Act)  as amended in

1990.  It sets forth procedures for determining emission

limitations based on maximum achievable control technology for

major sources who are required to apply for a new Title V permit,

revise an existing permit, or apply for a Notice of MACT approval

because the promulgation deadline for a MACT standard was missed

by greater than 18 months for an applicable source category.

     The manual is divided into five chapters and a four section

appendix.  Chapter 1 of this manual provides an overview of the

statutory and regulatory requirements and discusses the

procedures for applying for a Notice of MACT approval.  Chapter 2

outlines the criteria a permitting agency should use when

evaluating applications as well as possible approaches permitting

agencies may use  for determining the appropriate level of control

for  each source.  Chapter 3 describes the process for selecting a

control technology that meets the criteria discussed  in Chapter

2.   Chapter 4 describes the analysis that may be required to

assess the costs  of achieving the emission reduction, and any

non-air quality health and environmental  impacts and  energy

requirements associated with use of different control options.

Chapter  5 discusses the national databases that may assist  in the
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collection of available information.

     Part A of the Appendix illustrates examples for defining a

MACT-affected emission unit, and selecting a control technology

to meet MACT.  Part B is a question and answer forum.  It is

designed to deal with detailed questions on applicability and

other issues.  Part C of the Appendix contains a glossary of

terms and definitions.  In Appendix D, a complete list of source

categories of major sources is provided.  This listing is current

only to the date of this publication.  Readers are referred to

the Federal Register for any changes to this listing.

     It is hoped that this guidance document contains useful

information for implementation of MACT determinations.  For more

information on MACT determinations, the reader is advised to read

40 CFR Part 63, Subpart B, and Section 112 of the Act.

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                           Chapter 1.0

                       An Overview of the
                   MACT Determination Process
                       for Section 112(j)


1.1 Overview of Statutory Requirements

     Beginning after the effective date of an approved permit

program, (but no sooner than May 15,  1994,)  Section 112(j) of the

Clean Air Act as amended in 1990 (The Act),  requires an owner or

operator of a major source to submit either a new Title V permit

application or a revision to an existing permit if such major

source is part of a source category for which the promulgation

deadline for a relevant Section 112(d) or 112(h) standard has

been missed by 18 months.  The promulgation deadline for each

source category will be established through the regulatory

schedule in accordance with Section 112(e) of the Act.  A

proposed regulatory schedule was published on September 24, 1992

in the Federal Register.

       Section 112 (j) also requires States or local agencies with

approved permit programs to issue permits or revise existing

permits for all of these major sources.  These permits must

contain either an equivalent emission limitation or an alternate

emission limitation for the control of hazardous air pollutants

(HAPs) from the major source.  An equivalent emission limitation,

also referred to as a MACT emission limitation, will be

determined on a case-by-case by the permitting agency for each

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source category that becomes subject to the provisions of Section
112(j).  The MACT emission limitation will be "equivalent" to the
emission limitation which the source category would have been
subject to if a relevant standard had been promulgated under
Section 112(d) (or Section 112(h)).
     In accordance with Section 112(d), the MACT emission
limitation will require a maximum degree of reduction of
hazardous air pollutant emissions  (HAPs) taking into
consideration the costs of achieving such emission reductions,
and any non-air quality health and environmental impacts and
energy requirements.  For new sources, the MACT emission
limitation will be no less stringent than the emission control
that is achieved in practice by the best controlled similar
source.  For  existing sources the  MACT emission limitation will
be no  less stringent than:
     the average emission limitation achieved by the  best
     performing 12 percent of the  existing sources  (for  which the
     Administrator has  emissions information), excluding those
     sources  that have, within  18  months before the emission
     standard is proposed or within  30  months before  such
     standard is promulgated, whichever is  later,  first  achieved
     a level  of emission rate or emission  reduction which
     complies, or would comply  if  the  source is not subject to
     such  standard,  with the  lowest  achievable  emission  rate (as
     defined  by  Section 171  (of the  Act))  applicable  to  the
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     source category and prevailing at the time,  in the category

     or subcategory for categories and subcategories with 30 or

     more sources;  or,

     the average emission limitation achieved by the best

     performing 5 sources (for which the Administrator has or

     could reasonably obtain emissions information) in the

     category or subcategory for categories or subcategories with

     fewer than 30 sources.



These minimum requirements for the MACT emission limitation for

new and existing sources are termed the "maximum achievable

control technology (MACT) floor".

     An alternate emission limitation is a voluntary emission

limitation that an owner or operator of a major source has agreed

to achieve through the early reductions program. (See 57 FR

61970.)  The alternate emission limitation can be written into

the permit in lieu of an equivalent emission limitation only if

the source has achieved the required reduction in HAP emissions

before the missed promulgation deadline for the relevant Section

112(d) (or 112(h)) standard.

     Section 112 (j) also requires EPA to establish requirements

for owners or operators and reviewing agencies to  carry out the

intent of Section 112(j).  These requirements are  contained in

Chapter 40, Part  63,  Subpart B of the Code of Federal

Regulations.

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1.2 Overview of the Regulatory Requirements
     The owner or operator or a major source is required to apply

for a Title V permit, when the promulgation deadline for a

relevant Section 112(d) as been missed.  The permit application

must be received by the permitting agency no later than 18 months

from the date that the promulgation deadline was missed.  EPA

also recommends that an owner or operator of a major source

subject to the provisions of Section 112(j) also be required to

obtain a Notice of MACT Approval before constructing a new

source, or reconstructing an existing source.  This

recommendation is discussed in greater detail in Section 1.3 of

this chapter.

     In preparing an application for a Title V permit or a Notice

of MACT Approval, the  owner must recommend a level of control and

appropriate monitoring, reporting and recordkeeping parameters

for control of HAP emissions from each existing source or new

source within the source category.  The recommended level of HAP

emission control should be based on the maximum achievable

control technology  (MACT), and be no less  stringent than the MACT

floor  (when information is available to determine the MACT floor

level of control.)

     Chapter 3 of this manual discusses a  process for developing

the information required  in the Title  V permit application or

application for a Notice  of MACT Approval.   The process  is termed

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the "MACT analysis".  This analysis includes a MACT floor

finding, establishing a MACT emission limitation and selecting a

control technology to meet this emission limitation.

     Ideally, State and local agencies will coordinate efforts

with other agencies, and with owners or operators of affected

major sources to develop a source category equivalent emission

limitation before the deadline for permit application submittal.

If a State or local agency can provide an owner or operator with

all available information, or if the State conducts the MACT

analysis, it would not be necessary for an owner or operator to

conduct an independent MACT analysis to complete the required

application.  The information made available from the State or

local agency can be used to complete the application.  However,

failure of any given permitting agency to make information

available to an owner or operator or conduct the MACT analysis in

advance to the application submittal does not relieve the source

of its statutory obligation to submit a permit application;  or,

if a permitting agency requires it, the obligation to apply for a

Notice of MACT approval.  Coordination of State efforts is

discussed in greater detail in Chapter 2 of this manual.

     Once the MACT  analysis is complete the owner or operator  can

prepare the Title V permit application or application for a

Notice of MACT Approval.  The application for a Title V permit

should be prepared  in accordance with the provisions contained in

40 CFR Part  63 and  40 CFR part 70 or CFR Part 71 whichever  is

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applicable to the major source.

     The requirements for new sources are also codified in 40 CFR

Part 63, Subpart B.  Section 1.3 of this chapter describes a

recommended process for determining that a new source will meet a

new source level of emission control.

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1.3  Administrative Review Process for New Sources

     1.3.1 Application Process

     Subpart B of 40 CFR Part 63 recommends that the permitting

agency require any owner or operator of a major source that is

subject to Section 112(j) of the Act undergo a preconstruction

review if the major source constructs a new source or

reconstructs an existing source and intends to commence

construction of this source after 18 months from the missed

promulgation deadline.  This preconstruction review process would

be automatically required if the new source also meets the

definition of a constructed, reconstructed or modified major

source established under the regulatory provisions for Section

112(g) of the Act, (also contained in 40 CFR Part 63, Subpart B.)

Some owners or operators may also be required to obtain a Part 70

or Part 71 revision if a source's existing Title V permit

prohibits the construction of a new source or reconstruction of

the existing source without first obtaining a permit revision.

When a revision to a permit is not specifically required in

advance of the major source change, and an owner or operator does

not voluntarily revise or obtain the Title V permit before

construction, EPA recommends that the permitting agency require

that the owner or operator obtain a Notice of MACT approval

before commencing construction of the proposed source.

     The Notice of MACT approval can serve as the mechanism to

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ensure federal enforceability of the requirements established

during the preconstruction review before such requirements are

incorporated into the Title V permit.  As required by Part 70,

the requirements contained in the Notice of MACT approval would

be incorporated into the permit within 12 months from the start-

up of the source.  This would be done through either a

significant permit revision or an administrative amendment to the

permit.

     After receiving an application for a MACT determination, the

EPA recommends that the permitting agency have 30 calendar days

to review the application for completeness.  No later than 30

calendar days from the date that an application is received, the

reviewing agency should notify the owner or operator in writing

that the application is complete or that additional information

is required.  If the reviewing agency fails to issue a status of

completeness notice within the 30 day period, the application

could automatically be deemed complete.  After a notice of

completion is issued, the reviewing  agency should have 60

calendar days to issue a preliminary Notice of MACT Approval  or

disapprove the application.  The 60-day period could begin on the

date that the notice of completion  is issued.

     Before issuing a final disapproval of an application, the

reviewing agency should inform the  applicant  in writing of the

intent and grounds for the disapproval.  The  applicant should

have 30 days  from the date of notification to supply  additional

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information,  or amendments to the application.   If no additional

information is received in 30 days,  a final disapproval should be

issued.  If additional information is submitted,  the reviewing

agency should have 30 additional days to review the information

and issue a preliminary Notice of MACT approval or issue a final

disapproval of the application.  A final disapproval should be in

writing and should specify the grounds on which the disapproval

was based.

     In order for the requirements in a Notice of MACT Approval

to be federally enforceable, EPA and the public must be provided

the opportunity to review the notice before final issuance.  EPA

recommends that the Notice of MACT Approval undergo a 45 day

review period, during which the EPA or the public may comment on

the preliminary notice.  The final Notice of MACT approval could

then be issued after this public review period.  Figure 1

provides a suggested format for the Notice of MACT Approval.

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                            Figure 1

            Example Notice of MACT Approval
                     Notice  of MACT Approval
                   CFR 40, Part 63,  Subpart B
    Maximum Achievable Control Technology  Emission Limitation
                              for
          Constructed,  Reconstructed  or Modified  Source


     This notice establishes federally enforceable maximum
achievable control technology emission limitation(s) and
requirements for Name of  manor source for  the MACT-affected
emission unit(s) located  at  location  all MACT-affected emission
units.  The emission limitations  and  requirements set forth  in
this document are federally  enforceable on effective date of
notice.

A. Major source information

     1.   Mailing address of owner or operator:


     2.   Mailing address for location of  manor source;

     3.   Source category for manor  source:

     4.   MACT-affected emission  unit(s):   List all emission
          unit(s) subject to this Notice of MACT  Approval along
          with the source identification number if applicable.

     5.   Type of modification,  construction or reconstruction:
          Describe the action taken  by  the owner  or operator of
          the major source that  triggered  the requirements of  40
          CFR Part 63, Subpart B.

     6.   Anticipated commencement date  for construction.
          reconstruction or  modification:

     7.   Anticipated start-up  date  of  constructed, reconstructed
          or modified emission  unit(s):

     8.   List of the hazardous  air  pollutants  potentially
          emitted bv MACT-affected  emission unit(s):   List  all

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          hazardous air pollutants that are or could possibly be
          emitted from the affected emission unit(s).  Any
          pollutant not listed in this section can not be emitted
          by the emission unit without an amendment to the Notice
          of MACT Approval.


B.  MACT Emission limitation

     1.   The above stated owner or operator shall not exceed the
          following emission limitation(s) for the above stated
          MACT-affected emission unit(s). Write in emission
          standard or MACT emission limitation for overall
          hazardous air pollutant emissions from each affected
          emission unit.  If the permitting authority determines
          that an individual pollutant emission limitation is
          appropriate, it should also be listed in this section.

     2.   The above stated owner or operator shall install and
          operate the following control technology(s), specific
          design equipment,  work practice, operational standard,
          or combination thereof to meet the emission standard or
          MACT emission limitation listed in paragraph 1 of this
          section.  List all control technologies to be installed
          by the owner or operator and which emission units the
          control technologies will reduce HAP emissions from.

     3.   The above stated owner or operator shall adhere to the
          following production or operational parameters for the
          technologies listed in paragraph 2 of this section.
          State all production or operational parameters.  For
          example:
               The owner or operator may, subject to [name of
               agency] approval, by pass the emission control
               device for a limited period of time for purposes
               such as maintenance of the control device.

               The owner or operator shall operate and maintain
               the control equipment such that it has a 95%
               hazardous air pollutant destruction efficiency.

               The owner or operator shall not operate the MACT-
               affected emission unit for greater than 6 hours in
               any 24 hour period of time.
C. Monitoring requirements

     For each MACT emission limitation and operational
     requirement established in Section B  (MACT emission
     limitation) the  above stated owner or operator  shall comply

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     with the following monitoring requirements.  State all
     monitoring requirements. For example:
          After installing the control equipment required to
          comply with Section(B)(1) visually inspect the internal
          floating roof, the primary seal, and the secondary
          seal, before filling the storage vessel

          The owner or operator shall calibrate, maintain and
          operate a continuous monitoring system for the
          measurement of opacity of emissions discharged from the
          control device required in Section(B)(2) according to
          the following procedures:


D. Reporting and Recordkeeping Requirements

     List all reporting and recordkeeping requirements in this
     section.  For example:
          The owner or operator shall maintain at the source for
          a period of at least 5 years records of the visual
          inspections, maintenance and repairs performed on each
          secondary hood system as required in Section(B)(2).


E.  Other requirements

     1.   The above stated owner or operator shall comply with
          all applicable requirements specified in the general
          provisions set forth in Subpart A of 40 CFR Part 63,
          including but not limited to notification operation and
          maintenance, performance testing, monitoring,
          reporting, and recordkeeping requirements. If there are
          any specific requirements that the reviewing agency
          would like to clarify, those requirements should also
          be stated in this paragraph. This paragraph could also
          include requirements for emergency provisions and
          start-up and shut-down procedures.

     2.   In addition to the requirements stated in paragraph 1
          of this section, the owner or operator will be subject
          to these additional requirements.  Any additional
          requirements not specified in Subpart A of 40 CFR Part
          63 should be stated in this paragraph.  If the
          reviewing agency wishes to require a mandatory retest
          of a failed performance test that should be stated in
          this paragraph, along with any other requirements
          specified by the reviewing agency.

F.  Compliance Certifications

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The above stated owner or operator shall certify compliance
with the terms and conditions of this notice according to
the following procedures:  This sections should include a
description of the terms and condition that the owner or
operator will use to certify compliance, as well as, the
format and frequency of the certification.
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1.3.2 Contents of Application:
     After the owner or operator has determined a MACT emission
limitation and selected the MACT, the owner or operator should
prepare an application for a Title V permit or Notice of MACT
Approval.  There is no standard Federal form for the application;
however, individual States may develop there own application
forms.
     All applications for a MACT determination should contain the
following information:
     (a)  The applicant's name and address;
     (b)  A brief description of the major source, its source
          category or subcategory, and a description of the
          affected emission units;
     (b)  A notification of intention and date to construct,
          reconstruct, or modify;
     (c)  The address  (physical  location) of the affected
          emission unit;
     (d)  The expected commencement date of construction,
          reconstruction, or modification;
     (e)  The expected completion date of construction,
          reconstruction, or modification;
     (f)  The anticipated date of start-up;
     (g)  A list of HAPs emitted by the emission unit  and  rate  of
          emission;
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(h)   The uncontrolled emissions for  the  emission unit;

(i)   A description of the MACT including technical

     information on the design,  operation,  size, estimated

     control efficiency,  etc.;

(j)   Supporting documentation  such as a  the costs, non air

     quality health and environmental impacts and energy

     requirements analysis;

(k)   Controlled emissions for  the emission  unit;

(1)   Any federally enforceable limits already imposed on the

     affected emission unit;

     (n)  Other information  which may be required pursuant

          to 40 CFR Part 63,  Subpart A
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                           Chapter 2.0

                    The MACT Determination...

                a Permitting Agency's Perspective



2.1  Criteria for the MACT Determination

     The process of reviewing the Title V permit application or

the application for a Notice of MACT Approval  to determine an

equivalent (MACT) emission limitation is called a MACT

determination.  For MACT determinations under  Section 112(j), the

MACT emission limitation should be comparable  to the emission

limitation(s) or requirements that would likely be imposed if a

Section 112(d) or Section 112(h) emission standard had been

promulgated for that source category.  The Clean Air Act sets

forth specific criteria for setting a hazardous air pollutant

emission standard under Sections 112(d) and Section 112(h).

These criteria should also be used when establishing the MACT

emission limitation under Section 112(j).

     In conducting the MACT determination, the permitting agency

must determine if the owner or operator has recommended an

appropriate MACT emission limitation(s) or other requirements for

the MACT-affected emission unit, given the expected performance

of the maximum achievable control technology  (MACT).   When

conducting a MACT determination, the  permitting agency should

evaluate the application to determine  if the  recommended MACT

emission limitation, and the suggested control technology meet

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the following criteria:

     (a)  When a relevant emission standard has been proposed

          pursuant to Section 112(d) or 112(h) of the Act, the

          MACT emission limitation and control technology

          selected by the owner or operator achieves all emission

          limitations and requirements of the proposed standard.

     (b)  When a relevant emission standard has not be

          promulgated or proposed pursuant to Section 112(d) or

          Section 112(h):

          (1)  The owner or operator documents a MACT floor

               finding based on all available information, and

          (2)  When a positive MACT floor finding is made,  the

               application recommends a MACT emission limitation

               and selects a control technology that is at least

               equal to the MACT floor and achieves the maximum

               degree of emission reduction of the hazardous air

               pollutants with consideration to the costs,, non-

               air quality health and environmental impacts and

               energy requirements associated with the emission

               reduction; or,

          (3)  When a negative MACT floor finding is made, the

               owner or operator recommends a MACT emission

               limitation and control technology to meet this

               limitation with consideration to costs, non-air

               quality health and environmental impacts, and

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               energy requirements after evaluating all control

               technologies that can be identified through

               available information and that have been

               successfully demonstrate in practice for a similar

               source; and,

          (4)   When a MACT emission limitation can not be

               prescribes due to the nature of the process or

               pollutant, the owner or operator designates a

               specific design,  equipment, work practice,

               operational standard, or a combination thereof,

               that achieves a maximum degree of emission

               reduction.

The MACT floor finding is a determination of whether a level of

HAP emission control that is equal to the MACT floor can be

determined using available information.  The MACT floor finding

is discussed further in Section 3.6 of Chapter 3.  The definition

of available information is discussed in Section 2.3 of this

Chapter.

     The MACT emission limitation could be expressed as a

numerical emission limitation on the total quantity of HAP

emissions from the source in tons per year (tpy);  or, it could

be expressed as unit per production ratio.  The MACT emission

limitation could also be a performance standard based on the

expected efficiency of MACT in reducing HAP emissions.  If it is

infeasible to prescribe a specific numerical limitation or

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reduction efficiency the MACT emission limitation can also be

expressed based on a design,  equipment,  work practice,

operational standard, or any combination of these.

     If an individual hazardous air pollutant is of particular

concern, a MACT limitation should also be placed on that

pollutant based on the expected level of reduction with MACT in

place.  Reviewing agencies have discretionary authority to impose

an individual MACT emission limitation on a specific hazardous

air pollutant.  In addition to recommending the MACT emission

limitation, the reviewing agency should specify any requirements

that are necessary in order to make the emission limitation

federally enforceable as a legal and practical matter.   This

involves establishing appropriate operational or production

limits and monitoring parameters to ensure compliance with the

MACT emission limitation.  The following section discusses

compliance provisions in greater detail.
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2.2 Compliance Provisions

     Each Title V permit and Notice of MACT approval must contain

sufficient testing, monitoring, reporting, and recordkeeping

requirements to ensure that the MACT emission limitation is

federally enforceable as a legal and practical matter.

     In order to be federally enforceable, operational limits or

production limits must be imposed on the source in addition to a

blanket emission limitation.  For example, a blanket 40 tpy MACT

emission limitation on HAPs would not be federally enforceable.

In addition to the blanket emission limitation, a source may be

required to comply with a production limitation that limits the

amount of gallons used per hour in the operation; or the source

may be required to comply with an operational limitation on its

hours of operation and emission rate, that when multiplied

together can result in emissions from the source that do not

exceed 40 tpy.

     Production limits are restrictions on the amount of final

product which can be manufacture or otherwise produced at the

source.  Operation limitations are other restrictions on the

manner in which a source is run.  Operation limitations include

limits on quantities of raw material consumed, fuel combusted,

hours of operation, or conditions which specify that the source

must install and maintain controls that reduce emissions to a

specified emission rate or level.

     When the permit or Notice of MACT Approval requires an add-

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on control, operating parameters and assumptions that can be used

to determine the efficiency or emission rate of the devise should

be specified in the document.  For example, a source may have a

MACT emission limitation that requires a control devise to be

installed and operated at a 95% efficiency rate.  An operational

limit on the range of temperatures that the devise can be

operated under could be sufficient to ensure federal

enforceability, if operating the control devise within this

temperature range ensures that the devise achieves a 95%

destruction efficiency.

     If establishing operating parameters for control equipment

is infeasible in a particular situation, a short term emission

limit (e.g. Ibs/hr) would be sufficient provided that such limits

reflect the operation of the control equipment, and additional

requirements are imposed to install, maintain, and operate a

continuous emission monitoring system (GEM).  A Title V permit or

Notice of MACT Approval should also specify that CEM data may be

used to determine compliance with the MACT emission limitation.

     If parameter monitoring of a production or operational limit

is infeasible due to the wide variety of coatings or products

used or the unpredictable nature of the operation, emission

limits coupled with a requirement to calculate daily emissions

may be required.  For instance, a source could be required to

keep the records of the daily emission calculation, including

daily quantities and the HAP content of each coating used.

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     For either operation or production limitations to be

enforceable as a practical matter,  the limitations should extend

over the shortest practicable time period,  generally not to

exceed one month.  If it is not practicable to place a monthly

limit on the source, a longer time can be used with a rolling

average period.  However, the limit should not exceed an annual

limit rolled on a monthly basis.

     In addition to conveying practical enforceability of a MACT

emission limitation, the Title V permit or Notice of MACT

Approval should require testing or instrumental or

noninstrumental monitoring that yields data this is

representative of the source's operations and can be used to

certify the source's compliance with the terms and conditions of

the Title V permit or Notice of MACT Approval.  Such testing or

monitoring requirements may be in the form of continuous emission

monitoring systems, continuous opacity monitoring systems,

periodic testing, or it may consist of recordkeeping designed to

serve as monitoring.  If periodic testing is required, the

specific EPA approved method or equivalent method that is to be

used should be specified in the permit or notice.
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2.3 Available Control Technologies

     Section 112(j) states that permits issued pursuant to

Section 112(j) shall contain an equivalent emission limitation.

This emission limitation is to be "equivalent" to that which the

source would have been subject to if an applicable Section 112(d)

or Section 112(h)  emission standard had been promulgated.  In

order to establish an emission limitation that would be

equivalent, the permitting agency must determine the equivalent

emission limitation with consideration to the MACT floor using

available or reasonably available emissions information.

     For the purposes of a Section 112(j) MACT determination,

emission information is considered available or reasonably

obtainable to the permitting agency if the information can be

obtained from EPA's Office of Air Quality, Planning and

Standards, the  EPA's National MACT database or other publically

available databases  (See Chapter  5), from State or local agencies

or within the permitting agency  itself.   A permitting authority

is not required to obtain additional information  from databases

or other State  and local agencies  if the  information used  to

propose a Section  112(d) or  Section 112(h) standard is used  to

establish the MACT floor.

     It is not  necessary for the MACT  floor to be determined

based  on emissions information  from every existing source in the

source category if such information is not available.   Once  a

permitting agency  has  obtained  available information,  the MACT

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floor can be determine using this information if it is

representative of the source category.

     EPA realizes that the information that is reasonably

available or obtainable for the permitting agency is not

necessarily reasonably available to the owner or operator.

Owner's or operator should submit an application for Title V

permit or a Notice of MACT Approval based on information that the

owner or operator is able to obtain.  The permitting agency

should use the completeness of application review period to

determine if the owner or operator should consider additional

information that is reasonably available to the permitting

authority.  An amended application should be submitted  if

additional  information should be consider in the MACT analysis.

Once the application  is deemed complete, additional  information

that comes  available  does not need to be considered  before

issuing the Title V permit, or Notice of MACT Approval  if the

information was  not reasonably available at  the time of the

completeness  determination.
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2.4 Approaches to the MACT determination

     Section 112(j) states that permits issued pursuant to

Section 112(j) shall contain an equivalent emission limitation.

This equivalent emission limitation is to be determined on a

case-by-case basis.  The EPA views the case-by-case determination

required under Section 112(j) and that required under Section

112(g)  (modification, construction and reconstruction provisions)

to  be fundamentally different.  While Section 112(g) would

require a case-by-case determination for each source, EPA views

the determination  under Section 112(j) to be a case-by-case

determination for  each source category, or a "source category-by-

source  category" determination.  EPA would like to  see a

consistent approach  in defining the boundaries of the existing

source  and new  source, and defining the level of  control  required

for all sources  in the source category.

      Several  different approaches  to the MACT determination

process could be taken by  a permitting  agency.  An  agency could

wait  until all  applications for permits are  received to  determine

the equivalent  emission  limitations that would apply to  all  the

sources.   Or, an agency  or a group of  agencies could conduct a

"MACT analysis" based on available information before the

deadline  for  application submittal.

      The  first  approach  requires  less upfront coordination on the

part  of the  permitting agency.   While a permitting agency is not

 legally bound to conduct an information search before reviewing

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the permit applications, the permitting authority will need to

assure that all available information has been considered in

evaluating the application.  If a permitting agency chooses to

wait until an application is received to determine the extent of

information that is available, several permit applications may

need to be revised to reflect information identified by the

agency.  Also, under this approach each application will need to

undergo public review.  The implications of this are that there

may be less consistency in the source category by source category

equivalent emission limitation for each major source.  While this

may be unavoidable when each permit  is reviewed on an  individual

basis, a permitting agency may need  to justify any discrepancies

between the level of  control required  for existing sources  within

the same  source  category.

      The  second  approach would allow a permitting agency  to

convey  information to an applicant  in  advance of the  application

submittal.  A permitting agency  could  conduct an  information

search  to determine  the available information, or  a  "coalition"

of permitting agencies could  be  formed to  facilitate  the

 information  exchange.   Once  the available information is

 identified the permitting  agency could conduct  a MACT analysis

 (See  Chapter  3)  to determine  the appropriate level of control for

 each  source.   The control  level  could be established through a

 State regulation or general permit.  The following section of

 this  chapter discusses the concept of general permits in greater

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detail.

     If a permitting agency is unable to establish the level of

control through a State regulation or general permit, the

available information could be used for information exchange with

each permit applicant.  This would assure greater consistency in

control levels recommended by the applicants.
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2.4 General Permits

     A general permit is a type of Title V permit.  A single

general permit could be issued by a permitting authority to cover

a number of sources.  The specific requirements for a general

permit are contained in 40 CFR Part 70.6(d).

     The general permit can be written to set forth requirements

for an entire source category, or portion of the source category.

The facilities that are covered by the general permit, should be

homogenous in terms of operations, processes, and emissions.  In

addition, the facilities should have essentially similar

operations or processes and emit pollutants with similar

characteristics.   The facility should be subject to the same or

substantially similar requirements governing operations,

emissions monitoring, reporting, or recordkeeping.

     Because the case-by-case determination under Section  112(j)

is a source category-by-source category determination  of an

equivalent emission limitation, the permitting agency  could  use

the general permit as a mechanism  to  issue Title  V permits to the

entire  source category, or  specific emission units within  the

source  category.   By using  this mechanism, a permitting agency

would not  be  required to  issue  individual  permits to  sources

covered by the  general  permit.  Also,  once the general permit has

been  issued and after opportunity for public participation,  EPA

review  and affected State review,  the permitting  authority may

grant  or deny a source's  request  to  be covered by a  general

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permit without further outside review.

     Major sources that do not require a specific Title V permit

for any other reason, could be covered by the general permit

indefinitely.  For a major source that already has a Title V

permit, the owner or operator can apply for coverage under the

general permit, and then incorporate the general permit

requirements into the source specific permit through an

administrative amendment at permit renewal.
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                            Chapter 3

                        The MACT Analysis



     For most source categories, the process of recommending a

level of control involves a number of decisions either on the

part of the owner or operator preparing an application for a

Title V permit or Notice of MACT Approval, or a permitting agency

who is conducting a MACT determination.  First, the source

category boundaries must be defined.  All points within this

boundary that emit one or more hazardous air pollutants are

subject to control through an eguivalent emission limitation and

must be addressed in the permit application(s).  Within this

source category boundary there may be one or more existing

sources  (stationary sources) for which an equivalent emission

limitation will be established.  The existing  source boundary may

be  synonymous with the source category boundary, or a single

source category may contain  several existing sources.

     For each existing source,  the MACT  floor  level of control

must be determined.  The application submitted by an owner  or

operator must recommend an equivalent  MACT  emission limitation

that is no  less stringent  than  the MACT  floor,  but could  be more

stringent  if a  greater degree of  HAP emission  reductions  can be

achieved with consideration to  the costs, non-air quality health

and environmental  impacts  and energy requirements associated with

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achieving the additional emission reductions.

     The process by which these decisions are made have been

termed the MACT analysis.  The following sections of this Chapter

describe a MACT analysis process that EPA has developed to meet

the requirements of 40 CFR Part 63, Subpart B as described in

Section 2.1 of Chapter 2.



3.1 Overview of the MACT Analysis Process

     Along with determining the existing or new source

boundaries, the MACT analysis uses available information to make

a MACT floor finding.  There are several possible situations that

may arise in the course  of conducting a MACT analysis.  First,

the MACT floor could be  determined, and control technologies that

meet the MACT floor requirement could be identified.  This is

known as a positive MACT floor finding.  Another possible outcome

is that the MACT floor equals "no control".  The third possible

outcome is that the MACT floor can not be determined.  This could

be due to the nature of  the pollutants emitted  from the source,

the lack of available data, or because there are less than five

sources in the source category.  In these cases, a negative MACT

floor finding is made.

     Because of the variety of situations that  could  arise, the

MACT analysis has  been divided into three tiers.   Figure  2

diagrams the steps for Tier I, Tier II and  Tier III of the

analysis.  If a positive MACT floor finding is  made,  the  owner or

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           Figure 2   The  MACT Analysis
Tier I -- Making a
MACT Floor Finding

1)  Identify the MACT-affected
   emission unit.

2) Make a MACT floor finding:
 f
i  if   '
"i positive '
      if
     negative J
4) Identify MACT
          I
 Tier II - Considering
 All  Control Technologies

1)- List all available
   control technologies.
2) Eliminate technically
   infeasible control options.
3) Conduct a costs, non-air quality
   health and environmental impacts,
   and energy requirements analysis.
4) Identify MACT
                                        I
   Tier
 -- Establishing a MACT Emission Limitation
1)  Establish the MACT emission limitation (MEL).
2) Select a control technology to meet MEL.
3) Establish monitoring, reporting and recordkeeping parameters.
4) Submit application.	.

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                                                  Proposal
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operator or a permitting agency is only required to complete Tier

I and Tier III of the MACT analysis.  This analysis allows the

owner or operator or a permitting agency to compare the costs,

non-air quality health and environmental impacts and energy

requirements associated with using control technologies that

obtain a level of HAP emission reductions that is equal to or

greater than the MACT floor.  If the MACT floor can not be

determined or is equal to "no control"  (a negative MACT floor

finding), the owner or operator is also required to complete Tier

II of the analysis.

     All MACT analyses should begin with Tier I.  During this

Tier, the owner or operator or the permitting agency will

identify the emission points subject to a MACT determination,

 (the MACT-affected emission unit,) determine the existing

emission unit or new emission unit boundaries, and make a  MACT

floor finding for each emission unit  (the MACT-affected emission

unit.) The owner or operator or the permitting agency  can  make  a

MACT floor finding by using available  emissions  information  to

determine  if:  (1) a specific MACT floor level of control  can be

calculated;  (2) the very  best  control  technology can  be

 identified;  or,  (3) there is a previous case-by-case  MACT

determination  for a  source within that source category.   The

procedures detailed  Chapter 4  explain several acceptable  methods

 for  determining a MACT  floor level  of control.

      If  a  negative MACT floor  finding is made the  owner  or

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operator would move to Tier II of the MACT analysis.  The purpose

of Tier II is to identify all control technologies using

available information, including work practices, and pollution

prevention methods that could reasonably be applied to the

emission unit subject to the MACT determination.   Available

control technologies include but are not limited to: reducing the

volume of, or eliminating emissions of pollutants through process

changes, substitution of materials or other techniques; enclosing

systems or processes to eliminate emissions;  collecting,

capturing, or treating pollutants when released from a process,

stack, storage or  fugitive emission point;  using designs,

equipment, work practices, or operational standards  (including

requirements  for operator training or certification);  or,  a

combination of any of these  methods.  Strategies  for  identifying

available  control  technologies  are discussed  later  in  this

chapter.

      Once  a  list of available control technologies  has been

developed, each control  technology should be  evaluated to

consider  the  costs,  non-air  quality  health  and  environment

impacts,  and  energy requirements associated with  using each

control  technology.  The control technology(s)  achieving the

maximum  degree of  HAP emission  reductions  taking  into

consideration the  costs  of achieving such  emission reductions and

the non-air  quality health and  environmental  impacts and energy

requirements should be selected as  MACT.   Once  MACT has  been

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selected through either Tier I or Tier II of the analysis, the

owner or operator should move to Tier III.

     In Tier III, a MACT emission limitation(s)  should be

established based on the degree of emission reductions that can

be achieved through the application of the maximum achievable

control technology (MACT); or, a design,  equipment, work practice

or operational standard, or combination there of, should be

designated if it is infeasible in the judgement of the permitting

agency to prescribe or enforce a specific MACT emission

limitation based on MACT.  The owner or operator or the

permitting agency should also suggest conditions and appropriate

monitoring parameters to make this emission limitation federally

enforceable.

     Once the owner or operator has made a MACT floor finding,

established a MACT emission limitation, and selected a control

technology to meet this  limitation, the owner and operator should

apply for a Title V permit, or Notice of MACT Approval in

accordance with the procedures contained in 40 CFR Part 63,

Subpart B and 40 CFR Part 70.
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3.2  A Detailed Look at the MACT Analysis

Tier I - Making a MACT floor finding

Step 1 ~ Identify the MACT-affected emission unit(s)
     In accordance with the provisions established in 40 CFR Part
63, Subpart B, the owner or operator is required to  identify all
emission points emitting one or more HAPs within the source
category boundary.  These  "affected emission points" will  be
grouped into  emission units  (MACT-affected emission  units).  Each
of these emission units will be subject  to a MACT determination.
     When  a relevant emission  standard has been proposed,  the
application should  reflect boundaries for the MACT-affected
emission unit that  are  consistent with the existing  source
boundaries, affected  emission  points, or other  portion of the
major source  identified by the proposed  emission  standard.  When
 no relevant  emission  standard  has been proposed,  the MACT-
 affected emission unit will be determined on a  case-by-case
 basis.  Section 3.3 of this chapter discusses principles for
 determining the MACT-affected emission unit on a case-by-case
 basis.
 Step 2 — Make a MACT floor finding
      The owner or operator will need to determine if there is
 enough information available about other emission units to
 calculate a  level of HAP  emission control that is equal to the
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MACT floor for each type of emission unit undergoing review.  For

new or reconstructed sources, the MACT floor (or best controlled

similar source) should be determined using emissions information

on similar emission units from within and outside of the source

category.  (Section 3.4 clarifies the term similar emission

unit.)  For existing emission units, the MACT floor should be

calculated using only emissions information on other emission

units within  the source category.

     An owner or operator can avoid calculating a specific

emission  control level that  is egual to the MACT floor, while

still making  a positive MACT floor  finding by selecting the  very

best control  technology.  The owner of operator is referred  to

existing  EPA  control technology guideline documents  (CTG)  and

background  information documents  (BID).  These document may help

identify  best control  strategies  for  the control of  HAPs  from  a

given  type  of emission unit.  An owner  or  operator  could also

develop a list of  available control technologies  (similar to that

which would be developed under  a  Tier II  analysis)  and establish

a MACT emission limitation based  on the  control  technology that

 achieves a maximum reduction in hazardous air pollutant emissions

with consideration to the costs of achieving the emission

 reductions,  and the non-air quality health and environmental

 impacts,  and energy requirements.  However, minimal consideration

 should be given to cost in  such an analysis.  If an owner or

 operator chooses not to, or is unable to identify a MACT floor

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level of control by using any of these methods,  the owner or

operator will be required to review all available emissions

information to determine if a specific MACT floor level of

control can be found.  The easiest method for determining a

specific MACT floor level of control is to rely on a previous

MACT determination that was made for a similar emission unit

within the source category.  A previous MACT determination could

have been made for a similar emission unit due to a construction,

reconstruction or modification according to the provisions of

Section 112(g).  The owner or operator is referred to any

existing Federal, State or local data bases as well as the public

record to determine  if a MACT determination for a similar

emission unit has recently been made.  This MACT determination

can be used to establish the MACT floor, a MACT emission

limitation, and  select a control technology as long as there is

no reason to believe that the MACT  floor may have changed  since

the effective date of that determination.  Reasons to believe

that the MACT floor  may have changed would include, but are not

limited to, the  passing of a State  regulation in a particular

State that specifically regulates that type of emission unit.

And, the close down  or start up of  a number of major  sources

within the source category.

     If no previous  MACT determination has been made, or  the

owner or operator would  like to calculate a more current  MACT

floor, the owner and operator can use  emissions  information that

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is available for other emission units within the source category.
The degree of emission reductions can be calculated by referring
to existing State and local regulations, or by computing a
control efficiency rating or emission reductions ratio.  All of
these methods are detailed in Chapter 4.
     If the MACT floor can not be determined or it is equal to
"no control", a negative MACT finding has been made.  Under these
circumstances the owner or operator should discontinue Tier I of
the analysis and begin with Tier II as  later outlined  in this
section of this chapter.

Step 4 — Identifying MACT
     When a  positive MACT  floor  finding is made,  the  owner or
operator will need  to  identify control  technologies that  reduce
HAP emissions from  the MACT-affected  emission  unit to the  maximum
extent and  to a level  that is  at least  equal to the MACT  floor.
The control technology that achieves  the maximum degree of HAP
emission  reductions with consideration  to costs,  non-air  quality
health and  environmental impacts,  and energy  requirements is
MACT.   A  permitting agency has discretion to  determine the weight
that  will be given to each one of these factors in identifying
MACT.   In doing so, a control technology that exceeds the degree
 of emission reductions that is equal to the MACT floor may be
 identified as MACT.  Under no circumstances should MACT be less
 stringent than the MACT floor.
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     In general, a control option that reduces overall HAP

emissions to the greatest extent should be identified as MACT;

however, there may be occasions when the hazard to human health

and the environment of a particular HAP warrants the selection of

a MACT specifically for the control of that HAP.  Identification

of more than one control technology may be necessary when an

emission unit has multiple HAP emissions.  An owner or operator

is advised to consult with the reviewing agency to determine  if

this  is the case.   After this step is completed an owner or

operator should skip to Tier  III of the analysis.
           Tier II - Considering all control technology



 Step 1 —  List available control  technologies

      Using available information,  the owner or operator or

 permitting agency should develop a list of control technologies

 that have been successfully demonstrated in practice for similar

 emission units.  Similar emission units are discussed in more

 detail in Section 3.4 of this chapter.  In addition, the owner or

 operator may wish to consider innovative technologies and

 transfer technologies that might reasonably be applied to the

 MACT-affected emission unit.
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Step 2 — Eliminate technically infeasible control technologies

     All control technologies that could not be applied to the

MACT-affected emission unit because of technical infeasibility

should be eliminate from the list.  An owner or operator should

be prepared to justify the elimination of a control technology in

the application for a MACT determination.



Step  3 — Conduct a costs, non-air quality health and

          environmental impacts, and energy requirements analysis

      The owner or operator or the permitting agency should

conduct a detailed analysis  on all of the available control

technologies.  The efficiency of each control technology in

reducing overall HAP  emissions should be determined.  A reviewing

agency may  require an owner  or operator to  select MACT based  on

the degree  of  emission reductions achieved  for  one or more

specific HAPs  when the risk  to human  health and the environment

warrants establishing MACT emission  limitations specifically  for

these HAPs.  Otherwise, MACT should  be  selected based on  an

overall  reduction  of  all  HAP emissions.   It should be noted that

the application of more than one control technology may be

necessary  in order to address multiple  HAP emissions.

      After determining the control efficiency of each available

 control technology,  the owner or operator should identify the

 control technology(s) that allows for a maximum degree of HAP

 emission reductions with consideration to the costs of achieving

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such emission reductions, and the non-air quality health and

environmental impacts and energy requirements.  This is the MACT.

See Chapter 3 of this guidance document for a more detailed

discussion of the costs, non-air quality health and environmental

impacts, and energy requirements analysis.
       Tier
III — Establishing a MACT emission limitation
 Step  1  —  Establish  a  MACT  emission  limitation  (MEL)

      The owner  or  operator  should  determine  the degree  of

 emission reduction that can be obtained  from the MACT-affected

 emission unit,  if  MACT is applied,  and properly operated and

 maintained.   The MACT emission limitation should be based  on an

 overall reduction  of all HAP emissions;   however, if possible,

 the efficiency of  the MACT in reducing each potential HAP

 emission should also be stated.  The permitting agency will also

 have the discretion to establish a MACT emission limitation for

 an individual HAP when the risk to human health and the

 environment warrants such an emission limitation, or when such a

 limitation is necessary to make the overall HAP emission

 limitation federally enforceable.

      Chapter 4 discusses three ways to establish a MACT floor:

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using State and local regulations, control efficiencies and

emission reduction ratios.  If State and local regulations are

used to establish the MACT floor, the MACT emission limitation

may be based on a specific emission limitation contained in a

regulation such as 10 Ibs/per gallon of coating applied.  In

other cases, the regulations may be based on a specific design or

work practice.  It may not be feasible to establish a specific

numerical or efficiency limitation, in such cases.  If it is

infeasible to prescribe a specific emission limitation, The MACT

emission limitation  should be based on the application of a

specific design, process, or control technology.

     When control efficiencies are used to establish  a MACT

floor, the MACT emission  limitation  (MEL) can be  computed by

multiplying the efficiency of MACT by the uncontrolled emission

level  (UCEL)  of the  emission unit as follows:

                   MEL = UCEL * MACT efficiency

The reader  should refer to Section  4.4  for a  definition  of

uncontrolled  emission level.

     When  the emission reduction ratio  is used  to determine the

MACT floor,  the MACT emission  limitation  can  be computed by

multiplying the uncontrolled emission  level by  the emission

reduction  ratio  of  MACT using  the following  formula:
                     MEL = UCEL * (1 -
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Step 2 — Select a control technology to meet the MACT emission

          limitation

     Once the MACT emission limitation is established, the owner

or operator should determine the control technology that should

be applied to the emission unit that will allow the source to

meet the required MACT emission limitation.  In many cases, this

will be the MACT technology.  However, in some cases, the

emission unit may already be controlled to a some extent with an

existing control devise.  The owner or operator could demonstrate

that using additional control strategies in combination with

existing controls will allow the emission unit to achieve  the

required emission reductions.   For  instance, an emission unit may

currently be  controlled  with a  baghouse.  MACT for  the emission

unit  may be an  electric  static  precipitator.  The emission unit

may be able to  meet  the  MACT emission limitation by installing a

series of baghouses  in  lieu of  the  electric  static  precipitator.

The amount  of additional control  required  (ARC)  can be  computed

by subtracting  the MACT  emission  limitation  from the controlled

emission level  (CEL) (See Section 4.4 for  the  definition of CEL)

as follows:



                          ARC = CEL - MEL



 If ARC is equal to zero or is a negative number, no additional

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control is required.  The emission unit is currently meeting the

criteria for MACT.  If ARC is a positive number,  the owner or

operator must reduce hazardous emissions by this amount.  The

reader is referred to Section 4.4 for a definition of controlled

emission level.

     Owners or operators are reminded that the application of a

case-by-case MACT to an emission unit does not exempt that owner

or operator from complying with any future emission standards

affecting that emission unit.  The MACT floor emission limitation

as calculated on a case-by-case basis should be considered only a

relative indicator of the future MACT emission standard.  Changes

in technology or application of controls to under-controlled

sources may shift the MACT floor to a higher control level,

additional emissions information may be available that generates

a different level of control for the MACT floor, or a control

technology that is more effective in controlling HAP emissions

may be selected based on the relative cost of applying that

technology on a nationwide basis.  Owners or operators may wish

to consider applying control strategies that exceed the MACT

floor requirement.



Step 3 — Establish appropriate monitoring, reporting and

          recordkeeping parameters



     The owner or operator or  the permitting agency  should

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identify monitoring parameters to assure compliance with the MACT

emission limitation.  Section 2.2 of Chapter 2 discusses

compliance provisions in greater detail.



Step 4 — Prepare application for a Title V permit or Notice of

          MACT Approval

     Once a control technology(s) is identified and the MACT

emission limitation(s) is established,  the owner or operator

should prepare an application for a Title V permit or Notice of

MACT Approval consistent with the procedures  contained in  40 CFR

Part 63, Subpart B.
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3.3 Determining the MACT-affected emission unit

     The purpose of a case-by-case MACT determination is to

determine that all affected emission points will meet a MACT

emission limitation.  A MACT emission limitation will be

established for an emission unit known as the MACT-affected

emission unit.  The MACT-affected emission unit could either be a

single affected emission point, or a combination of affected

emission points.

      There are four basic principles to follow when designating

the MACT-affected emission unit.  The principles can be

summarized as  follows:  1)  When a relevant Section 112(d) or

Section 112(h) standard has been proposed, the owner or operator

and the permitting  agency should refer to the relevant  standard

to determine  the MACT-affected  emission unit; or,  (2) When a

source  category on  the source  category list is designated as a

specific piece of  equipment, the MACT-affected emission unit is

that  piece of equipment or  apparatus;  or,  (3)  The EPA's  Office

of Air  Quality Planning and Standard's should be  consulted to

determine  if  a suggested  method for  grouping of  affected  emission

points  is  available;  or,  (4)   Emission points  should  be combined

into  a  single MACT-affected emission unit when  the combination of

points  leads  to  a much more cost-effective method of  control,  and

achieves a greater degree of emission reductions when compared to

point-by-point compliance.

      The best indicator  of how a source category may be regulated

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after the promulgation of a relevant standard is found in a

proposed standard.  For this reason, EPA believes that owners or

operators and permitting agencies should follow the guidelines in

the proposed standard for determining the MACT-affected emission

unit for a Section 112(j) MACT determination.  Although there may

be no proposed standard for the source category, and EPA may have

missed the promulgation deadline for that source category,

information on the source category may have been collected which

allows EPA to recommend a specific method for determining the

emission unit for a Section 112(j) MACT determination.

Therefore, EPA should be consulted before attempts are made to

define the MACT-affected emission unit on a case-by-case basis.

EPA can be contacted through the Control Technology Center

Hotline operated by the Office of Air Quality Planning and

Standards at (919)-541-0800.

     When an affected emission point(s) is associated with a

piece of equipment or apparatus specifically listed on the source

category list,  that affected emission point(s) is the MACT-

af fected emission unit.   The source category list (See Appendix

D) contains sources that are defined by a manufacturing or

process operation, or as an individual piece of equipment.  In

developing the source category list, EPA determined that some

individual pieces of equipment have the potential to emit major

amounts.  For example, under the fuel combustion industrial

grouping, stationary internal combustion engines are listed as a

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source category of major sources.   When a source category is

designated by a single type of apparatus, the EPA believes that

the intent is for emission limitations and requirements to be

placed on that specific piece of equipment.  As such, if a

Section 112(j) determination is conducted for any one of these

source categories, the specific piece of equipment or apparatus

should be designated as the MACT-affected emission unit.  Other

examples of apparatus that are listed as a source category or

major sources are municipal waste incinerators, process heaters,

and stationary turbines.  The owner or operator should review the

list found in Appendix D to determine other source categories

that could be defined as the MACT-affected emission unit.

     Otherwise, individual affected emission point can be

considered a MACT-affected emission unit, or a group of affected

emission points can be combined into one affected emission unit.

There are several ways in which emission points could be  combined

to form an emission unit.  A  few points  could be combined, an

entire process unit could be  included  in the MACT-affected

source, or the MACT-affected  source could  be as large as  the

source category boundary.

     For example, a single emission point  such  as a  storage  tank

could be consider the MACT-affected emission unit.   Or,  emission

points from  a distillation column, a  condenser  and distillate

receiver could be consolidated into one  emission unit.   Larger

groupings  of emission points  maybe appropriate  when  a single

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control technology can be used to control the aggregation or when

a pollution prevention or waste reduction strategy is considered.

For instance, the entire wastewater treatment operation could be

considered one emission unit.  Collectively, a single steam-

stripper could be used at the beginning of the operation to

remove HAPs from the wastewater and prevent downstream emissions

from occurring.  Another example is illustrated with a surface

coating operation.  Rather than individually controlling the

emissions from a spray booth, flash-off area, and bake oven,

switching to a water-based paint could reduce emissions from all

of these emission points.

     Another reason to combine affected emission points into a

single emission unit  is that many major sources are already

subject to regulation under 40 CFR Part 60 and Part 61.  In

promulgating these standards, "affected facility" definitions

were developed to designate the apparatus to which a standard

applies.  It may make sense to use these same boundaries to

designate the  "MACT-affected emission unit" subject to a MACT

determination.  It should be noted that a particular piece of

apparatus or equipment should not be excluded from a MACT

determination  because of an  applicability "cut-off" established

under  a Part 60 or Part 61 regulation.

     Emission  points  could be consolidated  into an emission  unit

that is as  large  as the source category boundary  for  several

reasons.  First,  the  MACT floor  needs to be calculated

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specifically for the MACT-affected emission unit.   The

information that is available to calculate the MACT floor may

only be available for the source category as a whole,  not

individual points within the category.   Also,  the operations of

some source categories are quite variable.  Either the nature of

the process requires a large latitude of flexibility in

establishing the emission unit that should be controlled, or the

types of facilities within the category are so diverse that it

only makes sense to compare the existing sources on a source

category wide level.  In these instances, a source category wide

MACT-affected emission unit could allow some emission points to

be under controlled while others are controlled to a level that

would exceed the level of control that would be placed on that

individual point through the application of MACT.   Permitting

agencies are cautioned that it would be generally inappropriate

to include emission points associated with equipment leak

emissions into such a MACT-affected emission unit.

     There are some situations which would not make the

combination of emission points reasonable.  First, the combined

emission unit can not generate an emission unit that is  so unique

that it precludes comparing the emission unit to other sources in

the source category.  Second, the combining of emission  points

should reduce emissions from all of the affected emission points

within the MACT-affected emission unit through use of a  control

technology that  affects all of those emission point, or  involves

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recycling or reuse, or constitutes an overall source reduction
strategy as defined in the Pollution Prevention Act, P.L. 101-
503.  The types of activities that would be considered pollution
prevention or source reduction measures include changes in
technology, process or procedures, reformulation or redesign of
products, and substitution of raw materials.  A decrease in
production rate alone would not constitute a source reduction
strategy unless the rate reduction was associated with a
pollution prevention measure such as increasing efficiency of the
operation.
     Determining the MACT-affected emission unit on a case-by-
case basis is a complex undertaken.  While this document includes
this step as a separate component of the Tier I approach, in
actual practice the identification of methods to control specific
groups of emission units will be an integrated process with the
identification of  control technology options.  Some aggregations
of  emission points may be inappropriate because the information
available to calculate the MACT floor would dictate combining
emission points into certain emission units, or because  controls
applied to the unit would not achieve a MACT level of control
when compared to point-by-point compliance or some other
combination of emission units.  Appendix A provides an example of
ways in which available control technologies would affect the
aggregation of emission points into an emission unit.
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3.4  Similar Emission Units

     When an owner or operator constructs or reconstructs an

emission unit a MACT emission limitation(s)  must be meet based on

a new source level of control.  This emission limitation should

be based on the emission reductions achieved by the best

controlled similar source.  Also, when a MACT floor can not be

determined for an existing emission unit during Tier I of the

MACT analysis, the owner or operator is required to identify all

available control technologies, using available information, that

could be applied to a similar emission unit.  For the purposes of

case-by-case MACT determinations under Section 112(j), a similar

source is a similar emission unit.  If two emission units have

similar emission types and could be controlled using the same

type of control technology, those emission units would be

considered similar for the purposes of a case-by-case MACT

determination.  For instance, plastic extrusion is used  in  both

the plastic manufacturing  industry and graphic art industry.  The

emissions from these  industries  may be similar and be amendable

to the same type of control technology.

     The EPA  developed an  emission classification  system to be

used for determining  emission types for  case-by-case MACT

determination.  The  five emission  classifications  are as follows:
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Process vent or stack discharges - the direct or indirect

discharge of an organic liquid, gas, fume, or particulate by

mechanical or process-related means.  Examples would be

emission discharges from columns and receiving tanks from

distillation, fractionation, thin-film evaporation, solvent

extraction, air and steam stripping operations, absorbers,

condensers, incinerators, flares, and closed-looped

biological treatment units.



Equipment  leaks -  fugitive emissions from the following

types  of equipment: valves, pumps,  compressors, pressure

relief devices, sampling connection systems,  open-ended

valves and lines,  flanges,  agitators, sampling connection

systems, and  valve connectors.



Evaporation and breathing  losses -  emissions  from storage or

accumulation  of product or  waste material;   for  example:

stationary and mobile  tanks,  containers,  landfills,  and

surface impoundments,  and  pilings of  material or waste.



Transfer losses  - emission of an organic liquid,  gas,  fume,

vapor or particulate resulting from the agitation of

material during  transfer of the material from one unit to

 another.   Examples of such activities are filling of mobile

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                                                 Proposal
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     tanks,  dumping  of  coke  into  coke  quench  cars, transfer  of

     coal  from bunker  into larry  car,  emptying  of baghouse

     hoppers,  and sludge  transfer.



     Operational losses - emissions  resulting from the  process

     operation which would result in fugitive emissions if

     uncontrolled by hoods or vacuum vent,  or other  vent systems.

     Examples of operation loses  are emission resulting from

     spray coating booths, dip-coating tanks, quenching towers,

     lubricating stations, flash-off areas,  or  grinding and

     crushing operations.



     The classification scheme has been developed to serve as a

general guide in identifying available control  options.  When

using the list of classifications, consideration should be given

to the concentration and the type of constituents of a gas

stream.  While two pieces of apparatus are classified within the

same emission type, this does not automatically mean that the

emission points can be controlled using the  same type of control

technology.  For instances,  storage tanks and landfills are both

listed in the evaporation and breathing losses classification,

but  it is unlikely that  a storage tank and landfill would be

controlled with the same technology.   In order for an  emission

unit to be considered  similar it must fit both criteria: have a

similar emission type  and be controllable with the  same

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technology.

     Use of this classification system can be illustrated with an

owner or operator of a major source within the captan production

source category (a source listed on the source category list in

Appendix D,) who adds additional product accumulation vessels

 (tanks) and additional pipes, pumps, flanges and valves to direct

the product to the tanks.  After reviewing a database during

Tier I of  the MACT analysis, the owner or operator determines

that there are no regulations controlling HAP emissions from

pumps within the source  category;   and, there is not  enough

 emission  information  available  on  other emission units within the

 source category to calculate a  MACT floor.   During Tier II of the

 analysis,  the  owner  or operator discovers that  the Synthetic

 Organic  Chemical Manufacturing  Industry  (SOCMI)  source category

 has  regulations  for  controlling equipment  leaks.  Because the

 pipes, pumps,  and  flanges all  have equipment leak emissions,  the

 emission units in  the SOCMI source category would be considered

 similar  emission units;   and,  the regulations for SOCMI  equipment

 leaks should be considered for the control of the MACT-affected

 emission unit during Tier II of the analysis.  Identification of

 a similar emission unit does not mean that the controls will

 automatically be applied to the MACT-affected emission unit.

 Costs,  non-air quality health and environmental impacts, and

 energy requirements should be used to assess the technologies

 ability to meet MACT criteria.

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3.5 Subcategorization

     When the source category list was developed,  sources with

some common features were grouped together to form a "category".

During the standard-setting process, EPA may find it appropriate

to combine several categories or further divide a category to

distinguish among classes, types, and sizes of sources.  EPA

chose to establish broad source categories at the time the source

category list was developed because there was too little

information to anticipate specific groupings of similar sources

that are appropriate for defining MACT floors for the purpose of

establishing emission standards.

     The broad nature of some source category descriptions may

pose some difficulty in establishing an appropriate MACT emission

limitation for a MACT-affect emission unit on a case-by-case

basis.  Subcategorization within a  source category for the

purposes of a case-by-case MACT determination should  be

considered only when there is enough evidence to  clearly

demonstrate that there are air pollution control  engineering

differences.  Criteria to consider  include process operations

 (including differences between batch and continuous  operations),

emissions characteristics, control  device applicability  and

costs,  safety, and  opportunities  for pollution  prevention.
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                           Chapter 4.0

                     The MACT Floor Finding

     During Tier I of the MACT analysis, an owner or operator or

the permitting agency is required to make a positive or negative

MACT floor finding.  A positive finding would be made if there is

enough information to determine a emission control level that is

at least equal to the MACT floor.  A negative MACT floor finding

would be made if:  (1) the MACT floor equals "no control";   (2) a

MACT floor can not be determined due to the nature of the

pollutant or process;  or,  (3) there is not enough emissions

information to compute a MACT floor.

     The EPA recognizes that computing  the MACT floor for  a MACT-

affected emission  unit may  be time  consuming  and  burdensome for

the  owner or operator or the permitting agency.   To  avoid

calculating a  specific emission  control level that  equals  the

MACT floor, while  still making a positive MACT floor finding, the

owner  or  operator  can establish  a MACT  emission limitation based

on use of  the  very best  emission control  technology.  The very

best emission  control technology will meet or exceed the level of

emission  reduction required by  a MACT floor finding.  Owners or

operators and  the permitting agency should refer to existing EPA

 control technology guidelines (CTG),  background information

 documents (BID,) existing New Source Performance Standards (40

 CFR Part 60,)  or existing National Emission Standards for

 Hazardous Air Pollutants (40 CFR Part 61) to determine if  these

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information sources can help to establish a particular control
technology as the best for controlling HAP emissions from the
MACT-affected emission unit.  An owner or operator may also
establish a control technology as the very best, by choosing the
control technology that achieves a maximum degree of reduction in
emissions of the HAPs with consideration to the costs, the non-
air quality health and environmental impacts, and energy
requirements.  Minimal consideration should be given to cost
impact in such an analysis.
     An owner or operator could also avoid calculating a specific
MACT floor by referring to existing databases to document whether
a MACT determination for another similar emission unit in the
source category has recently been made.  This MACT determination
could be used to establish the MACT floor for the MACT-affected
emission unit provided there is no reason to believe that the
control technology no  longer represents MACT.  This was
previously discussed in Section 3.1.
     Because the above methods will not always  clearly identify a
control technology or  emission  limitation that  meets the MACT
floor, an owner or operator  or  the permitting agency may  be
required to  review existing  emissions  information to  calculate a
specific MACT  floor.   Section  4.1 of  this  chapter discusses the
calculation  procedure  for  determining  an  "average emission
limitation".   This procedure establishes  a  hierarchical  system
for determining  the  average emission  limitation using the
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arithmetic mean, median or mode.

     Using the calculation procedures discussed in Section 4.1,

the EPA has established three acceptable methods for determining

a MACT floor.  If the emissions information is available, all

three methods should be considered before the owner or operator

concludes that a MACT floor can not be found.  The three methods

include using:   (1) existing State and local air toxic control

regulations;  (2) control efficiency ratings; or (3) emission

reduction ratios.   Figure 3 lists these methods.  Each of these

methods is discussed in greater detail later in this Chapter.

     The first method compares air pollution regulations in

different States.  This method is likely to require the least

amount of data search and analysis.  The second and third methods

base the MACT floor on a level of emission reductions, allowing

the MACT-affected emission unit more flexibility in determining

control technologies to meet the MACT floor.  The second method

is applicable only when the control technologies under

consideration can be assigned an efficiency rating  for HAP

emission reductions.  This is most-likely to occur  with  add-on

control devises.  The third method can be used  for  add-on  control

devises, work practices, recycling, reuse or pollution prevention

strategies.  Depending on the format of  available  information, a

hybrid of the three approaches  may be necessary.
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                       Figure 3              proposal
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              Acceptable Methods for
           Determining the MACT floor
Emission Reduction Ratios
Efficiency Ratings
Existing State or Local Air Pollution Regulations
Other Acceptable Methods
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4.1  Calculation of the MACT Floor

     Section 112(d) of the Act instructs EPA to set emission

standards for new sources based on the emissions control achieved

by the best controlled similar source and to set emission

standards for existing sources based on an average emission

limitation achieved by the best performing 12% of existing

sources or best performing five sources in the source category.

For new sources the direction provided by the Act is relatively

clear.  For existing sources, further clarification is required

by EPA to determine how an average emission limitation should be

computed.

     The word average can have several different meanings,

including arithmetic mean, median and mode.  EPA has developed

the following hierarchy for  determining the average emission

limitation that is equal to  the MACT floor.  First, if the

emissions data that is to be used to calculate the floor  is  in

the form of a numerical expression,  (i.e.  95% reduction),  the

MACT  floor should  be  determined by taking  the arithmetic  mean  of

the best performing 12% of  existing  sources or the best

performing five sources.  An arithmetic mean  is  calculated by

summing  all of  the data and dividing by the number of  data

elements in the calculation.  The following example  illustrates

this  concept:
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Example \

     The following emission limitations are representative of the

     best performing 12% of existing source:

          % reduction

               99                  Average emission limitation =
               99
               95                            656/7 = 93.7%
               93
               92
               89
               89
     Total     656

     # of sources = 7
     Under some circumstances the arithmetic mean results in a

number that may not correspond to the application of a specific

control technology.  For instance suppose the arithmetic mean of

emission  limitations of the best performing 12% of exist sources

is  equal  to 92.3%.  Application of control Technology X would

provide a source  91% control, while application of Technology Z

would  limit the source's emissions by 96%.  In most cases, when

the arithmetic mean can not be specifically achieved by the

application of a  control technology, the MACT floor should be

elevated  to the level  of control associated with  the control

technology that exceeds the MACT floor.  In Example 1, the MACT

emission  limitation should be no less stringent than 95%  control.

This concept  would not make sense  if there  is a  large  discrepancy

between the  amount of  emission reductions that  can be  achieved by
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available control options.   This is illustrated with the

following example:



Example 2

          An arithmetic mean is computed for the best performing

     12% of storage tanks.   There are 10 sources among the best

     performing 12% of storage tanks.  Two tanks are controlled

     by 99%, the remaining 8 tanks are not controlled.  The

     emissions limitations considered in the floor calculation

     are:

          % reduction

               99                                     ...
               99                  average emission  limitation =
                0
                0                       19.8%  reduction
                0
                0
                0
                0
                0
                0
      Total      198

      #  of sources = 10


 In this example,  no technology corresponds  to 19.8%  control,  and

 it might be inappropriate to elevate the MACT floor  to 99%

 control.

      If there is a  large discrepancy between the amount of

 emission reductions that can be achieved by available control

 options, the median should be used in lieu of the arithmetic mean
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to determine the average emission limitation equal to the MACT

floor.  A median is the value that falls in the middle of a set

of numbers when those numbers are arranged in an increasing order

of magnitude;  in other words, there will be an equal number of

values above and below the median.  If the middle falls between

two values, the median is equal to the arithmetic mean of those

two numbers.  This situation will occur when there is an even

number of values in the set of numbers.  When computing the

average emission limitation for the best performing 12% of

existing sources, the median will always be equal to the lowest

emission limitation achieved by the best 6% of sources in the

source category.  For example:



Example 3

          There are 84 sources in the source category.  The

     number of sources in the best performing 12% of source is

     equal to 10.  The median is to be computed for the following

     emissions data:

          % reduction
               24
               26             There are a total of 10 numbers
               30             the median would be the arithmetic
               30             mean of the 5th and 6th numbers
               33             in the column.
               40
               56             median =  (33 + 40)/2 = 36.5
               88
               93
               99
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     Like the computation of the arithmetic mean,  the value

obtained for the median may not always correspond to a specific

control technology.  If there is a control technology that

obtains slightly greater emission reduction than the median, the

MACT floor should be based on that control technology.  For

instances, in Example 3, the MACT floor would be equal to 40%

emission reductions.  This value coincides with the lowest

emission limitation achieved by the best performing 6% of

sources.  However, if there is a large discrepancy between the

control technologies used to establish a median such that no

technology could realistic obtain a reduction close to the

median, the mode should be used to calculate the MACT floor.

     A mode is the most frequent occurrence among a set of data.

In Example 1, the mode would be 99% emission reductions.   In

Example  2, the mode would be equal to 0% emission reductions;  and

the mode  in Example 3 would be  30.

     The mode may  also  be used  as a method to compute an  average

emission  limitation if  the emissions data  for a source category

is not  based on  a  numerical number.  This  could occur if  sources

were regulated by  several different equipment or work practice

standards.  Unless a  specific  level of  emission reduction can be

associated with  each  different  standard or unless the standards

can be  ranked  in some order  of  increasing  level  of  control,  an

arithmetic mean  and median  can  not be  calculated.   A mode could

be used if  one  of  the control  options  was  used  more frequently by

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one of the best performing 12% of existing sources.   For example:
Example 4

     There are 44 tanks in the source category.  5 sources would

     be among the best performing 12% of existing sources.  These

     five tanks are subject to the following regulations in the

     source category:

          3 of the 5 must be covered and vented to a carbon

          canister;

          2 of the 5 must use a fixed roof



     The mode would be to cover and vent the tank to a carbon

canister.

          The following sections of this chapter detail the three

acceptable methods for computing a MACT floor.  It should be

noted  that when the best controlled similar source is being

determined for a new or reconstructed source,  all references to

using  emissions information from within the source category

should be ignored.   Identifying the MACT floor for constructed

and reconstructed major sources requires that  the emission

information used to  determine the best controlled similar source

not be limited to within the  source category.  Readers  are

referred to Section  3.4 of this chapter for a  definition  of

similar  emission unit.
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4.2  Method 1 - Computing the MACT Floor Using Existing State and

     Local Regulations

     The steps for computing a MACT floor using this method are

listed in Figure 4.  The following describes these steps.



Step  (A) Conduct a geographical survey

     Determine the number of existing similar emission units in

the source category, and conduct a survey to determine the

geographical location of these similar emission units.  Group the

emission units according to the state or locality in which they

are located.

Step  (B)  Review State or local air pollution regulations

      Review  the different State or local air pollution control

regulations  that are applicable to the emission unit  in  each

State or  locality  where  the  emission unit is  located.



Step  (C)  Rank the State or  local  air pollution regulations

      For  the State and  local  regulations  identified  in  Step  B,

rank  the  regulations  in  order of  stringency.   The regulations

that  require the greatest level  of control  should be listed

first.
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                            Figure 4             proposal
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                     Using State or Local
                   Air Pollution Regulations
                to Compute the MACT Floor
Step A    Conduct a Geographical Survey
Step B     Review State and Local Air Pollution Regulations
Step C    Rank the Regulations according to Stringency
Step D    Determine the Percentage of Emission Units Complying with
          each Stringency Level
Step E    Determine MACT Floor
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Step (D)   Determine the number of emission units regulated by
each stringency level.
     For each level of stringency identified in Step  (C),  a
percentage of emission units required to comply with the
regulations should be computed.

Step (E)  Make a MACT floor finding
     For constructed  or reconstructed major source, the MACT
floor will equal the  most stringent State or local regulation
applying to a similar emission unit.  For a modified  major
source, the MACT floor will either be equal to  the arithmetic
mean of the best 12%  of existing emission units in the  source
category,  or the best 5 existing emission units in the  source
category.   If the  arithmetic  mean can not be calculated,  the
median  or  mode  should be  used to compute the MACT floor for
existing  sources.
      Figure 5  illustrates the following example of  this concept:
In Step (A),  the  owner or operator determines  that there  are 42
 similar emission  units in the MACT-affected emission unit's
 source  category.   Sixteen of the sources are located in State A,
 five in State B,  three in State C, and 18 in State D.  A specific
 numerical value can not be determined for all of these
 regulations,  but it is possible to list the regulations in order
 of stringency.   Upon reviewing the regulations in these four
 States, it is determined that States A and B have the most
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                            Figure 5

                Evaluation of State Regulations
                       for Emission Unit X
STATE
A
B
C
D
TOTAL
STRINGENCY*
1
1
2
3


# OF SOURCES
16
5
3
18
42
Total # of emission units

# of emission units within the top
6% of existing emission units

Stringency level top 6 emission
units must comply with

MACT floor
= 42
=3  (42 * 0.06)
= 1
  regulations
  in State A or B
*  Stringency is rated from the most stringent State regulation
beginning at 1 and increasing in number as the regulation  is
rated less stringent.
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stringent regulations for this source;  and, they are equally

stringent.  These State regulations are followed in stringency by

State C.  State D is the least stringent state; there are no

regulations and the sources are uncontrolled.

     State A and B regulate 50% of the sources.  Using the median

to compute the MACT floor, the MACT floor would be equal to the

least stringent regulations governing the most strictly regulated

3 sources  (42 * 0.06 rounded to the next largest whole number.)

In this  case, the MACT floor would be equal to either State A or

State B's  regulations.
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4.3  Method 2 — Computing the MACT Floor using Control

     Efficiency Ratings



     To use this method to calculated the MACT floor, the owner

or operator will evaluate emission units within the source

category that use add-on control devices or other methods whose

HAP control efficiencies have been clearly demonstrated.  See

Figure 6 for a summary table of the steps for using the control

efficiency rating.  The MACT floor and MACT emission limitation

can be computed as follows:



Step  (A)  Determine HAP emission reduction efficiency for each

          control device.

          For each similar emission unit in the source  category,

the ability of each control technology to reduce HAP emissions

should be determined as a percentage of reduction efficiency.

Acceptable methods for determining the efficiency rating  are:

      1)   Equipment vendor emission data and  guarantees;

      2)   Federal and  State enforceable permits  limits  on

          operation of the control technology;

      3)   Actual  reported  efficiency from the similar  emission

          unit.
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              Using Control Efficiency Ratings
                to Compute the MACT Floor
Step A     Determine Efficiency of Control Technology used by other
          Emission Units.
Step B     Determine the MACT Floor.
Step C    Compute an Uncontrolled Emission Level(UCEL) for the
          MACT-Affected emission unit.
Step D    Compute a Controlled Emission Level (CEL) for the
          MACT-affected emission unit.
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Step (B)  Calculate the MACT floor

     For new and reconstructed emission units,  the MACT floor

equals the level of emission reductions that can be obtained by

the control technology with the highest emission reduction

efficiency.  For existing emission units, the MACT floor equals

the arithmetic mean of the best five or highest 12% of control

efficiency ratings.  Or, if the median is used the MACT floor

equals the lowest control efficiency rating achieved by the best

6% of sources if there are greater than 30 sources in the source

category; or, the MACT floor equals the lowest control efficiency

rating among the best 3 sources if there are less than 30 sources

in the source category.  Under most circumstances, it should not

be necessary to use the mode to compute an average emission

limitation;  however, if it is used, the MACT floor would be

equal to  the most  frequent control efficiency rating among the

best performing 12% of existing sources  or the best performing

five sources.



Step  (C)   Determine the uncontrolled emission  level for  the  MACT-

           affected emission unit

     Use  the  same  procedure outline  in Step  D  of  Method  3  in

Section 4.4  of  this Chapter.
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Step (D)   Determine a controlled emission level for the MACT-

          affected emission unit

     Use the same procedure outlined in Step E of Method 3 in

Section 4.4 of this chapter.
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4.4  Method 3 - Computing the MACT floor Using  Emissions

     Reduction Ratios (ERR)



     The emission reduction ratio is a fraction of uncontrolled

emissions to controlled emissions.  The MACT floor is computed

using the emission reduction ratios.  To compute the emission

reduction ratio for each emission unit, the owner or operator

must review emissions data or other information to determine

uncontrolled and controlled emissions levels for these units.

The step-by-step process is detailed below and summarized in

Figure 7.



Step  (A)  Compute an uncontrolled emission level  (UCEL)  for each

similar  emission unit in the source category.

     The uncontrolled emission level is the annual sum of all  air

emissions for  every HAP that could  be  emitted  from all emission

points in the  absence of control  technologies  given  the  maximum

design capacity used by the  similar emission unit within the  five

year period  proceeding the date  of  application submittal.   For

new emission units, uncontrolled emissions should include the

current  design specifications  for that equipment in  an

uncontrolled state.

      For example,  in  1992,  an  owner and operator of  a major

source used  trichloroethylene  in a  degreasing operation.  In

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            Using the Emission Reduction Ratios
                to Compute the MACT Floor
Step A     Compute an Uncontrolled Emission Level (UCEL) for each
          emission unit.
Step B     Compute a Controlled Emission Level (CEL) for each emission
          unit.
Step C     Compute an Emission Reduction Ratio (ERR) for each emission
          unit.
                    ERR =  UCEL  - CEL
                             UCEL
Step D    Determine the MACT Floor.
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1993, the owner or operator switched to a water-based solvent in

the degreasing operation.  In 1994, the owner or operator changed

to using a low-VOC based solvent because the water-based solvent

performed poorly.  If a Section 112(j) MACT determination is

conducted for the emission unit, the uncontrolled emission level

would be computed using trichloroethylene in the calculation.  In

1995, after already receiving the Title V permit, the owner or

operator adds a degreaser  (a new emission unit) that uses water-

based solvents in the degreasing operation.  The uncontrolled

emissions for this affected emission unit would be based on the

design specifications associated with the water-based solvent.

     The uncontrolled emission  level should be based on tons/yr

unless the nature of the process is more accurately reflected by

computing the mass per production unit.  Acceptable methods  for

making this calculation  are:

      (a)  Engineering calculation using material balance or

          emission factors;

      (b)  Actual  emission  data  for the similar emission unit;

      (c)  Average annual hourly emission rate multiplied by  hours

          of  operation;

      (d)  Emission limits  and test data  from EPA documents,

          including  background  information documents;

      (e)  Equipment  vendor emission  data  and guarantees;

      (f)  State  emission inventory questionnaires  for comparable

          sources;

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     (g)   Federal  or State  enforceable  permit  limits; or,

     (h)   For equipment leaks  use,  "Protocols  for Generating

          Unit-Specific Emission Estimates for Equipment Leaks of

          VOC and  VHAP."



Step (B)   Compute  a controlled emission level  (CEL)  for each

similar emission unit or existing emission unit within  the source

category.

     The controlled emission level is the sum of all air

emissions for every HAP that could be emitted from all emission

points given the maximum design capacity currently in use by the

similar emission unit taking into consideration the application

of existing  control technologies and federally enforceable  limits

(or for the  emission unit undergoing the review,  those controls

that will be federally  enforceable if  approved as MACT) that  have

been placed  on HAP  emissions from that emission unit.  This

figure should be  based  on tons/year, unless the nature of the

process is more accurately  reflected on  a  mass per production

unit basis.  Acceptable methods for making this  calculation are:

      (a)  Engineering  calculations using material balance or

          emission  factors;

      (b)  Any reported or  measured emission that offers a  true

          representation  of yearly emissions;

      (c)  Average annual  hourly emission rate multiplied by hours

          of operation;

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     (d)   Emission  limits  and  test  data  from  EPA documents,

          including background information  documents;

     (e)   Equipment vendor emission data and  guarantees;

     (f)   State emission inventory  questionnaires for  comparable

          sources;

     (g)   Federal or State enforceable permit limits;  or,

     (h)   For equipment leaks  use,  "Protocols for Generating

          Unit-Specific Emission Estimates  for Equipment Leaks of

          VOC and VHAP."



Step (C)   Compute the emission reduction ratio (ERR)  for each

emission unit:

               ERR =  UCEL - CEL
                         UCEL



Step (D)  Determine the MACT floor.

     For new or reconstructed sources the MACT floor would be

equivalent to the highest ERR.  For existing sources, the MACT

floor equals the arithmetic mean of the best five or best 12% of

ERRs.  If the median is used, the  MACT  floor equals the lowest

ERR among the best  6%  of  ERRs or the  best  three  ERRs depending  on

the number of sources  in  the  source category.   If the  mode  is

used, the MACT  floor equals the most  frequently  occurring ERR

among the best  performing 12% of sources or  best 5 sources

depending on  the number of  sources in the  source category.


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     For example,  suppose a major source determined that there

are four emission units in the top 12% of existing emission units

for the source category.  These four emission units had emission

reduction ratios of 0.90, 0.92, 0.93, and 0.99.  The control

technologies used by these best performing 12% of similar source

are a wet scrubber, a solvent change, a condenser, and an

incinerator.  The arithmetic mean for these values equals 0.935.

If this value does not correspond to the application of a

specific control technology, the MACT floor would be equal to an

emission reduction ratio of 0.99.  If it is determined that

elevation of the MACT floor to this  level is infeasible, then the

median  should be computed  for these  sources.   The median would  be

equal to best performing 6% of sources  or the  lowest of the

highest two emission reduction ratios.  This is  equal to  0.93.
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4.5 Exceptions Emission Reduction Ratios
     In most circumstances the emission reduction ratio,  is a

reliable method for calculating the MACT floor.  However, there

are some circumstances when a very low emission reduction ratio

could be computed for a well-controlled emission unit.  This may

occur if pollution prevention strategies are used for greater

than five years at the major source, or a process has an

inherently low potential to emit hazardous air pollutants.  The

owner or operator could be reducing emissions to the maximum

extent possible without being able to credit the pollution

prevention strategy in computing the uncontrolled emissions.  The

uncontrolled and controlled emission rate could be nearly the

same, causing the emission reduction ratio to be a very  low

number.  A reviewing agency should keep such situations  in mind

when making a MACT determination.  In such instances, the

pollution prevention method should not be eliminated  as  a

candidate to meet the MACT floor.
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4.6  Other Methods to Compute the MACT Floor

     As future MACT standards are proposed or promulgated for

different source categories, more methods for determining the

MACT floor could be developed.  The reader is referred to the

Federal Register to locate any other methods for calculating the

MACT floor that have been approved by the EPA and used in

developing a MACT standard under Section 112(d) or 112(h) of the

Act.
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                            Chapter 5

                     Costs, Non-air Health
                   and Environmental Impacts,
                     and Energy Requirements


     Section 112(d)  of the Act specifies that if control

technology alternatives are being considered to establish an

emission standard•that would result in emission limitations more

stringent than the emission "floor";  or, if insufficient data

exists to specify an emission limitation based on the MACT floor,

then control technology alternatives must be evaluated by

considering costs,  non-air quality health and environmental

impacts, and energy requirements associated with the expected

emission reductions.

     The costs, non-air quality health and environmental  impacts,

and energy requirements discussed below are illustrative  only and

are not intended as an exclusive list of considerations for MACT

determinations.  Some of these factors may not be appropriate in

all cases, while in other  instances, factors which are not

included here may be relevant to the MACT determination.   The

discussion does not address the evaluation of  each factor nor the

weighing of any factor relative to  another.  Such determinations

should  be made  on a case-by-case basis  by the  owner/operator  and

permitting agency.  For the purpose of  this  discussion,  terms

such  as "emission control  system"  or "MACT  system" refer to

design,  equipment,  or  operating  standards and  inherently less


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polluting processes, as well as add-on control equipment.

     In general, the impact analyses for MACT determinations

should address the direct impacts of alternative control systems.

Indirect energy or environmental impacts are usually difficult to

assess, but may be considered when such impacts are found to be

significant and quantifiable.  Indirect energy impacts include

such impacts as energy to produce raw materials for construction

of control equipment, increased use of imported oil, or  increased

fuel use in the utility grid.  Indirect environmental impacts

include such considerations  as pollution at an off-site

manufacturing  facility which produces materials needed to

construct or operate a proposed control system.   Indirect  impacts

generally will not  be considered  in the MACT  analysis since the

complexity of  consumption  and  production patterns in  the economy

makes  those  impacts difficult  to  quantify.   For example,  since

manufacturers  purchase  capital equipment and  supplies from many

suppliers, who in turn  purchase goods from other  suppliers,

accurate  assessment of  indirect impacts may not be possible.  Raw

materials may  be needed to operate control equipment, and

 suppliers of these resources may change over time.  Similarly, it

 is usually  not possible to determine  specific power stations and

 fuel sources which would be used to satisfy demand over the

 lifetime of a control device.

      In most cases, duplicative analyses are not required  in

 preparing the MACT impact analyses.  Any studies previously

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performed for Environmental Impact Statements,  water pollution

permits, or other programs may be used when appropriate;

however, the permitting agency may consider any special economic

or physical constraints which might limit the application of

certain control techniques to an existing emission unit, such as

retro-fitting costs that would not be borne by a new unit, or the

remaining useful life of the emission unit.  The result may be

that the level of control required for an existing emissions unit

may not be as stringent as that which would be required if the

same unit were being newly constructed at an existing plant or at

a "greenfield" facility.  However, in no event shall the level of

control yield an emission limit less stringent than the MACT

floor when information is available to compute the MACT floor.
 5.1 Cost  Impacts

      Cost impacts  are  the  costs  associated with  installing

 operating,  and  maintaining alternative  emission  control  systems

 (add-on emission control devices or  process  changes.)  Normally,

 the submittal of very  detailed and comprehensive cost  data  is not

 necessary.   Presentation of the  quantified costs of  various

 emission  control systems  (referred to as  control costs,)  coupled

 with  quantities of HAP emission  reductions associated  with  each

 of the emissions control systems,  is usually sufficient.

      Once the  control  technology alternatives and emission

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performance levels have been identified, total capital investment

and total annual cost should be developed.  Total capital

investment (purchased equipment plus installation) and total

annual costs of each emission control system should be presented

separately.  Total annual coasts are comprised of operation and

maintenance costs  ("direct annual costs",) administrative changes

 ("indirect annual  costs"), plus overhead, taxes,  insurance, and

capital recovery costs minus recovery credits  (credit for product

recovery  and by-product sales generated  from the  use of control

systems and other  emission reduction credits.)  These costs

should be reported in  equal end-of-year  payments  over the time of

the  equipment.  Total  annual costs  should be reported on an

 overall basis,  as  well as an incremental basis.   The various

 emission  control  systems  should be  presented or  arrayed  in terms

 of increasing  total annual  cost.  The  incremental annual  cost of

 a particular  emission  control  system  is the difference  in  its

 cost and  the  cost of the  next  less  stringent  control.

      A method for determining  the excessiveness or acceptability

 of control costs  is the comparison  of  the cost-effectiveness of

 alternative control systems.   Cost-effectiveness is the ratio of

 total annual  costs (calculated using the above guidelines)  to the

 total amount (tons or Mg) of HAP removed.  Incremental cost

 effectiveness is calculated using the same procedure as outlined

 for calculating incremental annual cost.  Generally, cost-

 effectiveness falling within the range  of previously acceptable

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MACT decisions are not considered excessive.  Therefore,

consistency with the relative cost, or cost effectiveness, of a

past MACT determination for a similar source is an indication

that such a cost is reasonable for the MACT determination in

question.

     For most MACT determinations, a cost analysis focusing on

incremental cost-effectiveness of various MACT alternatives is

sufficient.  The analysis should include and distinguish the

various components used to calculate the incremental cost-

effectiveness of the control alternatives  (i.e., lifetime of the

equipment, total annual costs, tons of total HAP removed, etc.).

     If there is reason to believe that the control costs place a

significant burden on the entity being controlled, then the cost

analysis should include financial  or economic data that provide

an  indication of the affordability of a control relative  to the

source.  For example, if the per unit cost is a significant

portion  of the unit price of a product or  if the economic status

of  the industry is declining, then the cost analysis  should

present  the relevant economic or  financial data.   Financial  or

economic data should  include parameters such as after-tax income

or  total liabilities.  An example  of  a financial  criterion used

to  determine  affordability  would  be  the ratio  of  a facility's

capital  costs to  the  facility's  parent company's  total

liabilities.  This  ratio would provide an assessment  of the

company's  capital structure.

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5.2  Environmental impacts
     The environmental impacts concentrate on collateral
environmental impacts due to control of emissions of the
pollutant in question, such as solid or hazardous waste
generation, discharges of polluted water from a control device,
visibility impacts (e.g. visible steam plume),  or emissions of
other air pollutants.  The applicant should identify any
environmental impacts associated with a control alternative that
has the potential to affect the selection or rejection of that
control alternative.  Some control technologies may have
potentially significant secondary environmental impacts.
Scrubber effluent, for example, may affect water quality and land
use, and, similarly, technologies using cooling towers may affect
visibility.  Other examples of secondary environmental impacts
could include hazardous waste discharges, such as spent catalysts
or contaminated carbon.  Generally, these types of environmental
concerns become important when sensitive site-specific receptors
exist or when the incremental emissions reduction potential of
one control option is only marginally greater than the next most
effective option.
     The procedure for  conducting an analysis of environmental
impacts should be made  based  on a consideration of site-specific
circumstances.  In general, the analysis of  environmental  impacts
starts with the identification and  quantification of  the  solid,
liquid, and gaseous  discharges from the control device  or  devices
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under review.  Initially, a qualitative or semi-quantitative

screening can be performed to narrow the analysis to discharges

with potential for causing adverse environmental effects.  Next,

the mass and composition of any such discharges should be

assessed and quantified to the extent possible, based on readily

available information.  As previously mentioned, the analysis

need only address those control alternatives with any

environmental impacts that have the potential to affect the

selection or rejection of a control alternative.  Pertinent

information  about the public or environmental consequences of

releasing these materials should also be assembled.  Thus, the

relative environmental impacts  (both positive and negative) of

the various  alternatives can be compared with each  other.

     Also the generation or reduction of toxic  and  hazardous

emissions other than those  for which the MACT determination is

being  made  and compounds not regulated  under the  Clean  Air Act

are  considered part of the  environmental  impacts  analysis.  A

permitting  authority should take  into  account  the ability of  a

given  control  alternative  for  regulated pollutants to affect

emissions  of pollutants  not subject to regulation under the Clean

Air  Act in  making MACT decisions.   Consequently,  the ability of a

given  control  alternative  to  control toxic or  hazardous air

 contaminants other than those for which the MACT determination is

 being  made, should be considered in the MACT analysis.
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4.3  Energy Impacts

     Energy impacts should address energy use in terms of

penalties or benefits associated with a control system and the

direct effects of such energy use on the facility.  A source may,

for example, benefit from the combustion of a concentrated gas

stream rich in volatile organic compounds; on the other hand,

extra fuel or electricity is frequently required to power a

control device or incinerate a dilute gas stream.  If such

benefits or penalties exist, they should be quantified to the

extent possible.

     In quantifying energy  impacts, the application could

estimate the direct energy  impacts of the control alternative in

units of energy consumption at the source  (e.g.,  Btu, Kwh,

barrels of oil, tons of coal).  The energy requirements  of the

control options could be  shown in terms of total  and/or

incremental energy costs  per ton of pollutant  removed.   In many

cases, because energy penalties or benefits  can usually  be

quantified  in terms of additional cost or  income  to the  source,

the  energy  impacts analysis can be converted into dollar costs

and, where  appropriate, be  factored  into  the cost analysis.

     Indirect energy  impacts  (such as  energy to  produce  raw

materials  for construction  of  control  equipment)  are  usually not

considered.  However,  if  the reviewing agency determines,  either

independently or  based on a showing  by the applicant, that an

indirect energy  impact is unusual  or significant, the indirect

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impact may be considered.  The energy impact should still,

however, relate to the application of the control alternative and

not to a concern over energy impacts associated with the project

in general.

     The energy impact analysis may also address the concern over

the use of locally scarce fuels.  The designation of a scarce

fuel may vary from region to region, but in general a scarce fuel

is one which is in short supply locally and can be better used

for alternative purposes, or one which may not be reasonably

available to the source either at the present time or in the near

future.
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                           Chapter 6.0

                     Sources of Information


     There are currently several programs under development to

house and disseminate toxics information.  Some of these programs

are designed for specific, narrow purposes, while others are

employed in a broader range of uses.  Many data collection

programs are designed for immediate interface with the AIRS

toxics program, which is currently under development.

     The purpose of this chapter is to present various sources of

toxics information available in a database format.  EPA believes

the requirements of 112(g) can be less burdensome to both

industry and States by  employing a database system to calculate

the 12% floor which may involve using complex mathematical

algorithms and procedures.
BACT/LAER CLEARINGHOUSE INFORMATION SYSTEM  (BLIS)

     The BACT/LAER Clearinghouse, or the BACT/LAER Information

System  (BLIS)  is a database consisting of best achievable  control

technology  (BACT) determination  information on specific  sources,

to a process  level.   Database parameters include  facility

information;  process  description; pollutant information; control

device  type,  installation  date,  efficiency; and calculation

method; and stack test  information  if  it exists.

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     Participation in BLIS is on a voluntary basis.  If

participation in BLIS increases, it may be able to provide

sufficient information to determine the 12% floor with increasing

accuracy.

     BLIS has undergone substantial revision.  Additional fields

for use with toxics work have been added, changes to improve

"user-friendliness" of the system, such as menus and help screens

have been added, and BLIS is now available on the TTN Bulletin

Board.
JEI06 PROGRAMS

     The Joint Emissions Inventory Oversight Group (JEIOG),

support for a data system for air toxics emissions inventories

focuses on the expressed reguirements of the urban area source

program (UASP, Section 112(k), of the CAAA) and the Great Waters

Program (GWP, Section 112(m)).

     Under the JEIOG programs, there are both short term,

immediate needs and long-term needs.  Since the UASP data

collection effort is scheduled to be completed by mid-1994, JEIOG

may need to select a system  for immediately use by the Urban Area

Source Program.



     Urban Area Source Program

     The Urban Area Source Program  (UASP)  is collecting emission

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inventory data for use by mid -1994 to meet the CAA November 1995

date for development of a national strategy for control of HAP

emissions in urban areas.  The inventory focuses on an adequate

number of urban areas to "understand the urban area source

problem."  Baltimore, Chicago and Houston are the leading

candidate cities.  Other cities could be added (such as

Milwaukee, Detroit or Seattle) as the resources become available.

The primary data need is for a single year "snapshot" of

emissions data for use in developing the national control

strategy plan.  As of the date of this writing, JEIOG has not

committed to any single system for storing the UASP data.  AIRS

is under consideration with other database systems.



     Great Waters Program

     The Great Waters program requires HAP emissions data for

most of the U.S. and portions of Canada.  The Great Lakes region

probably requires the most attention.  Biennial assessments as

reports to Congress are required under the Great Waters program.

The first report is expected  in November 1993.  Emissions

inventory data are used primarily for input to models for the

assessment of the relative atmospheric loading of toxic

pollutants into the Great Lakes and other waterways.  Updates of

the emission inventory are anticipated to support the periodic

assessments and for input to  refined models as they become

available.

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GENERIC ICR DATA (SECTION 114)

     Under the Authority of Section 114, EPA developed a survey

to obtain the information needed to calculate regulatory floors

for both new and existing stationary sources (See Appendix     ).

This survey is commonly referred to as a "generic ICR",  or

information collection request.  It is customized within narrow

parameters for each source category, and comes in both a "long

form" and a "short form".  EPA sends the survey to facilities at

the time it initiates regulatory development for the affected

source category.  In other words, the survey is not sent to

facilities in all source categories at the same time.

     In the generic ICR, EPA requests information regarding each

compound identified as a HAP that is used in or emitted by any

operations, including fugitive emissions sources, occurring from

the source category at the facility.

     Recipients of the form are required to fill out the

information request as completely as possible from existing

information.  At a minimum, the facility must provide (1)

information of the presence of HAP emissions and  (2) HAP emission

estimates based on previously obtained test data or on

engineering calculations provided there is a basis for such

calculations.

     Since the Generic ICR data is collected by EPA from

industries, it is called "Agency data".  As such, it can not  be

used to update  (or replace) existing data which was obtained  from

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States,  or "State data".   The ICR data is currently stored and

analyzed on a commercial database software files.   The Agency is

evaluating options to make the ICR data "safe" (without

confidential information) and accessible to States on a workfile

within AIRS/AFS.
XATEF: TOXIC EMISSION FACTORS

     The requirements of the CAAA dictate immediate sampling and

analysis to obtain data for determination of emission factors.

These emission factors will be used to determine control

measures.  EPA developed screening methods for the development of

air toxics emission factors, and applies the screening to test

results as they become available for use.  The EPA is enhancing

the XATEF system  for housing and manipulating the data.  The

XATEF system  is being redesigned to export toxic emission

factors, in a form similar to the AFSEF package for criteria

pollutants.   The  new system should be available by the fall of

1992.

     The toxic emission  factors available through the XATEF

system will be rated A  (most reliable, based on several  tests

meeting high  confidence  criteria) through E  (least reliable,

having limited available information), similar to the way

criteria emission factors  are presented  in the AP-42.

      Toxic  emission  factors are being developed for  400  toxic

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compounds, of which about 170 are on the list of 189 HAPs in

Section 112(b).   About 40 of these have been targeted as

"critical" pollutants because they are found in a wide variety of

industries, and/or are especially toxic.  This group of about 40

toxic compounds have a rating of A or B, enabling users to arrive

at the most accurate emissions estimates presently possible.
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AIRS/APS NATIONAL OPERATING PERMIT SYSTEM
     The EPA promulgated a new part 70 of Chapter I of title 40
of the Code of Federal Regulations (CFR) on July 21, 1992,
establishing provisions for the Operating Permit Program, and the
minimum data elements of State operating permit programs.  States
must develop and submit programs for  issuing operating permits to
major stationary sources of HAPs.
     The requirements of Section 112(g)(2)  (A&B) are triggered by
the effective date  of a permit program under Title V in  any
State.  Section  112(g)(3)  states that "the  Administrator (or the
State)  shall establish reasonable  procedures for assuring that
the requirements applying  to  modifications  under this  section are
reflected  in the permit".
     The most  far-reaching program established under the CAAA  is
that of a  national  operating  permit  program under  Title  V.   The
National Air  Data  Branch  (NADB)  is developing  a database as a
 subsystem  under  AIRS/AFS  to handle the  new data coining in from
 States Title  V permit programs.   This database is  generally
 referred to as the permit system.   The permit system is under
 design to  provide much of the information needed for determining
 the MACT floor both for case-by-case MACT determinations and for
 MACT standards.   It is expected that this system will become
 available for use by the fall of 1993.
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AEROMETRIC INFORMATION RETRIEVAL SYSTEM (AIRS) TOXICS PROGRAM

     The Aerometric Information Retrieval System  (AIRS) was

designed and executed to accommodate the expansion of emissions

data.  AIRS Facility Subsystem (AFS) is the stationary source

component of this system and replaced the old NEDS as the data

repository for point source data (e.g., electric  utilities,

industrial plants and commercial enterprises).  Enhancement of

AIRS continues to support the new programs designated by the

CAAA.  The National Air Data Branch  (NADB) is currently

considering data support of the requirements  under Section 112

for HAP.
NATICH

      The  National  Air  Toxics  Information  Clearinghouse  (NATICH)

has  been  established by  EPA to  support  State  and local  agencies

in the  control  of  non-criteria  air  pollutants.   The NATICH

program has  both a database and a reporting capability.

      The  database  component of  the  clearinghouse contains

information  on  various air toxics regulatory programs

administered through State and  local agencies.   Elements such as

permitting,  source testing, ambient monitoring, agency contacts,

acceptable ambient limits and guidelines, and program overviews

are  all contained within the  database.   Information is collected

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on an annual basis by voluntary submittal from participating

agencies.



     Since its introduction in 1984, NATICH has undergone

periodic modifications in an attempt to expand and meet the needs

of the user community.  In the fall of 1989, a link was

established between NATICH and the Toxic Release Inventory System

 (TRIS).  A modification is in the planning stages to move the

database from the NCC's IBM mainframe onto the OAQPS TTN Bulletin

Board  System for easier and wider accessibility.
 STATE  AIR OFFICE  DATABASES

     Emissions  Standards Division (ESD)  staff have been working

 with STAPPA/ALAPCO to better characterize the toxics information

 available in database form and hard copy within the State air

 offices.

     Most States  have compiled pollutant information in some form

 in response to State Implementation Plan (SIP) requirements.

 Many States also have toxics information collection systems, as

 well as State requirements for toxics programs in the air

 offices.   Most States find that although internally their system

 is widely used (intra-State system), to down  load or upload data

 on an inter-State basis  is nearly impossible  (with the primary

 exception to this being  States within a transport region, and

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then usually under limited circumstances).   Many States have

expressed a keen interest in a National database that each State

could down load State-specific data into,  and upload multi-State

retrievals from.  This capability is met by three main systems in

EPA:  BLIS, AIRS, and NATICH.



     Many States use the Aerometric Information Retrieval System

(AIRS) to input their information and perform calculations and

retrievals.  When a converter  (an interface between AIRS and the

State system) is used, the data can be input directly into the

State system and the converter then enters it into the

appropriate fields in AIRS.  Data can also be retrieved from AIRS

into the State  format with a converter.

     Since many data sources are fed into AIRS/AFS, the system

becomes a repository of a vast amount of data.  A great deal of

this will be useful for case-by-case MACT determinations and MACT

standards.  This advantage  is  expected to become more visible as

the search for  the 12% floor for a  source category becomes a

common occurrence.

     Some  State data  is not  generally  found  in  the State systems

because  it is not needed  for their  current reporting

requirements.   However, much of the information missing  from the

database  system can be found in the files documenting  source

categories and  processes  of industry reports.   States  may  wish  to

enhance  their current systems  to hold  such additional  data fields

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and data elements from their participating industries.



                  OTHER  SOURCES  OF  INFORMATION



TRADE JOURNALS

     Caution should be taken when employing these sources,

especially in noting the method of emissions estimation, number

of tests which were used in developing estimates, and the

conditions under which tests were conducted.  Other factors which

may affect the emissions estimates should also be identified, and

the effects of their differences quantified as accurately as

possible.  Because results applicable to only one facility can

not be completely accurate for other facilities, this source of

information is not regarded as highly accurate.

     This source of information may be somewhat biased as trade

journals are commonly published and funded by the industry

members of a trade association.  However, these journals are

completely acceptable as long as the results used can be

substantiated.



TOXIC RELEASE INVENTORY  SYSTEM  (TRIS)

     This is a source of data that  was used to  identify HAP

emitters.  The TRIS database contains emissions data  reported by

individual industrial facilities as required under  Section 313  of

the Emergency Planning and Community Right-to-Know  Act  of  1988.

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Emissions data in TRIS are reported on a plant wide basis.

Standard Industrial Classification (SIC) Codes are reported in

TRIS but the entries are usually not specific enough to identify

categories of sources.   The TRIS database is reportedly capable

of identifying plants emitting pollutants listed in Section

112(b).
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                       List of References
Air Pollution Training Institute (APTI).   December 1983.

     Overview of PSD Regulations.  EPA 450/2-82-008.



Air Pollution Treaining Institute (APTI).  June 1983.  Air

     Pollution Control Systems for Selected Industries.

     EPA 450/2-82-006.



Environmental Protection Agency  (EPA).  May 1992.  Facility

     Pollution Prevention Guide.  EPA, 600/R-92/088.



Environmental Protection Agency  (EPA).  February  1992.

     Documentation  for Developing the  Initial  Source Category

     List.   EPA,  450/3-91-030



Environmental Protection Agency  (EPA).  June  1991.   Hazardous

     Waste  TSDF  - Background Information  for  Proposed RCRA Air

     Emission Standards.   EPA,  450/3-89-023  (a)  and (c).



Environmental Protection Agency  (EPA). October,  1990.  New Source

     Review Workshop Manual. EPA,  Research Triangle Park,  NC

      (Draft Document).
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Environmental Protection Agency (EPA), January 1990.  OAOPS	

     Control Cost Manual.  EPA, 450/3-90-006.



Environmental Protection Agency (EPA).  September 1986.  Control

     Technologies for Hazardous Air Pollutants.

     EPA, 625/6-86-014.
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                           Appendix A

          The following detailed examples presented in this

manual are for illustrative purposes only.  Numbers and values

presented in this Appendix do not necessarily reflect any known

cases and are not meant to establish any US EPA position

regarding MACT determinations for a particular MACT-affected

source.  These examples are fictitious and are designed to

highlight many of the subtle aspects of the MACT determination

process.  In many cases, the scenarios and available control

technologies have been grossly oversimplified to streamline the

presentation of the examples.

     The proceeding examples assume that  an owner  or operator has

already determined that the major source  will be constructed,

reconstructed or modified.

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                            Example l

                        Determining the

                   MACT-Affected Emission Unit



The owner or operator of a major source in the miscellaneous

metal parts source category is subject to a MACT determination

under Section 112(j).  The following is a description of the

source and the operations at the facility:



     A metal furniture manufacture produces military-

specification office furniture for use in military barracks.  The

plant currently operates 2080 hr/yr and produces 12,000 units of

furniture annually. Estimated emissions from the major source are

100 tpy of HAPs.



Existing unit operations include:

1)  wood processing

          Raw wood and  formica are glued  together to  form a

      laminate. The glue is  applied using  an automatic application

      system. Several  laminates are then positioned  in a press for

      glue curing.  Next, the  boards  undergo various woodworking

      operations  including,  cutting,  drilling,  and routing.

      Boards  are  either  transferred to assembly or directly

      packaged and  shipped.  Tetrachloroethylene is  a  component of

      the glue.   Glue stations are vented to emission  stacks on

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     the ceiling.  The stacks are currently uncontrolled.

          The glue is stored in 50 gallon drums.   Glue is

     transferred to the application equipment through a pumping

     mechanism.

          Estimated yearly emissions of HAP from this operation

     is 0.50 tpy.



2)  Metal Processing

     Metal stock is cleaned by immersion in a toluene dip tank.

A toluene, grease, and dirt sludge is produced which is pumped

from the bottom of the tank for disposal.  After cleaning the

metal undergoes various metalworking operations including

cutting, punching, folding and welding.  Pieces are partially

assembled, then transferred to one of two paint coating

operations.  The dip tank is currently controlled with a

condensing unit and a freeboard ratio of 0.75.  Yearly controlled

emissions are estimated at 19 tons/yr.  Uncontrolled emissions

are estimated at 55 tpy.
3)   Cleaning operations:

     The spray coating operations begins with a five-stage

cleaning.  The first stage is an alkaline-wash tank.  Next, parts

are sprayed with an iron phosphate solution.  The fourth stage is

a rinse tank.  Finally, parts are sprayed with a rust preventive.

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After cleaning, the parts are conveyed to a dry-off oven and then

the paint coating line.  No HAP emissions occur during this part

of the operation.



4)   Painting operations:

          There are currently four spray booths in the paint

     coating operation, and one dip-spray tank.  Large metal

     parts are coated using the spray booths. A one color coating

     is applied at a coating depth of 1 ml.  Two of the booths

     are  equipped with continuously recirculating water curtains

     to entrap paint overspray.  Entrapped paint solids and

     wastewater are dumped to a holding tank periodically.  Air

     filters are used  in  the two remaining spray booths.  The Air

     filters are periodically replaced.  The used  filters are

     placed  in storage drums for later disposal.

           All  spray booths are equipped with hand-held  spray

     guns.   Transfer  efficiency  is  estimated at  45%  for both

     types of  booths.  The paint is a high solvent paint

     containing  xylene and toluene  with  an estimated 35%  solids

     content and 65%  solvent content. The spray guns are

     periodically  sparged and  rinsed with  acetone to prevent

     clogging.  The acetone  paint  mixture  is sent to storage

     tanks for later  disposal.  Emissions from the booths are

     currently vented to the roof  with no  control devise.

           After painting parts are conveyed through a flash-off

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     area to one of two dry-off ovens and then to assembly. Small

     metal parts are dip-painted, allowed to air dry, and then

     transferred to the assembly area.

          Total annual HAP emissions from this area are estimated

     at 55 tpy.  Each spray booth contributes 8 tpy and each

     drying oven 4 tpy.  Estimated emissions from the dip-spray

     tank are 15 tpy.  No emission estimates are available for

     the flash-off area.



     From this description the following emission points are

indentified as potentially "affected emission points" by the

Section 112(j) MACT determination process:


     glue storage drums
     glue stations (stack emissions)
          —application equipment
          —curing presses
     dip tank*
     toluene storage tanks*
     toluene/sludge waste storage tanks*
     spray booths (stack emissions)
          — feed and waste lines
          — application equipment
     spray dip-tank
     flash-off area (large parts)
     drying area (small parts)
     paint storage tanks
     solvent storage vessels
     paint sludge storage tanks
     drying ovens (stack emissions)
     Air filter storage drums


     * These unit would be eliminated from any MACT-affected
     emission unit because the emission points would be part of
     the degreasing source category, not the miscellaneous metal


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     parts surface coating source category.


Possible MACT-affected emission unit scenarios:




Scenario #1   There would be five MACT-affected emission units:

     Wood processing
     Spray coating operations
     Storage tanks
     Equipment leaks
     storage drums

     The above scenario could make sense if a MACT floor could be

identified or control technologies could be applied to the

emission units.  In wood processing the emissions are vented to a

stack on the roof.  These emissions could be controlled with a

variety of add-on control devices.  The source could also

consider switching to a glue that has a lower concentration of a

HAP or does not contain any HAPs.

     In the spray operations, the source could switch to a low

solvent paint or water-based paint.  This control option would

need to be weighed against controlling the individual emission

points.  Other control options to consider would be an add-on

control devise to control the stack emissions from the spray

booth and oven, increasing the transfer efficiency of the  spray

application equipment, and controlling the drying, flash-off

areas, and the dip-spray tank with separate control technologies.

     Controlling the storage tanks as one emission unit may allow

flexibility in meeting MACT.  Some tanks could remain under

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controlled while others could be over-controlled.   This option

would need to be weighed against the cost effectiveness and

emission reductions of applying controls to all of the storage

tanks.  The storage drums could be placed in a contained area and

the emissions vented to one control devise.



Scenario #2


     Stack emissions (spray booths, glue stations, drying ovens)
     storage tanks and drums
     equipment leaks
     dip-spray tank

     In this scenario, the stack emissions from the spray booths,

glue stations and drying oven could all be vented to a single

control devise.  This option would need to be weighed against the

emission reductions that could be obtained by applying pollution

prevention strategies to the individual operations.  If the

storage tanks and drums are stored in a common location, such

that the emissions from the area could be vented to a control

devise, this emission point aggregation could make sense.  The

emission reduction would need to be weighed against controlling

the emission points separately.  If greater emission reductions

could be obtained by controlling these points separately, this

aggregation of points may not be acceptable.
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Scenario #3

     each storage tank
     each spray booth
     stack emissions from glue stations and drying oven
     equipment leaks
     each storage tank
     each storage drum
     dip-spray tank

     This scenario would generally be acceptable unless a

pollution prevention method could be applied to one of the

processes that could obtain a greater degree of emission

reductions then point-by-point compliance.
Scenario #4

     All emission points



     This  scenario would  generally  be unacceptable  because

equipment  leak  emissions  should  not be  included  in  a  source

category wide emission unit.
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Scenario #5

     equipment leaks
     remaining emission points

     This aggregation of emission units could be acceptable if

emissions information were available on HAP emissions or control

technologies from the source category as a whole, or if the

nature of the industry demanded a large degree of flexibility in

the application of MACT.  A justification for this conglomeration

would be necessary.
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                            Example 2

     Using control Efficiency Ratings to Determine the MACT Floor



     A MACT determination is to be conducted on a quenching

process at a coke-by product plant.  Hazardous emissions can be

released when the hot coke in the quench car is sprayed with

water to decrease the coke's temperature.  Phenol and naphthalene

emissions can occur in the gaseous state.  Other pollutants can

sorb to particulate matter and be collectively released.  The

owner or operator will need to conduct a MACT analysis to

recommend a MACT emission limitation and specify a control

technology to comply with the MACT floor for existing major

sources.  The owner or operator will begin with the Tier I

analysis.

Steps 1) Identify the MACT-affected emission unit(s)

     MACT-affected source:    quenching tower and coke car

     # of existing sources:   36

     The equipment used  in this production process include the

quenching tower, the coke car, water delivery system, and water

storage system.  After consulting  with the permitting agency, it

is decided that emission points from the quenching tower  and  coke

car should be considered one MACT-affected emission unit,  and the

water delivery system and water storage  system  as another

affected emission unit.  The example will be  continued  for only

the quench tower/coke car emission unit.

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Step 2) Make a MACT floor Finding
     Technology

1)   Use clean water

     to quench coke

     with baffles at the top

     of the quench tower
of plants using

    10
%efficiencv

 not

 quantifiable
2)   Use covered quenched car.

     Cool outside of car.

     Water does not impact

     coke.  Place car on cooling

     rack after quenching for

     additional heat

     dissipation.
                  almost 100%
 3)   Wet  scrubber,  connected

     to fixed  duct  system

 4)   Wet  scrubber,  mobile  unit

     attached  to coke quench  car

 5)   Dry  quenching  with inert

     gases.  Heat transported  to

     waste-heat boiler
    10
    14
 80-90%
 80-90%
                   99-100%
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     The owner or operator has decided to use the control

efficiency ratings to determine the MACT floor.   There are a

total of 36 existing sources.  The MACT floor would be equivalent

to the arithmetic mean of the control efficiency ratings for the

best five sources.  If a specific control efficiency rating is

not available for the best performing five sources, a median or

mode could be used to calculate the MACT floor.   Using the

information provided, the median of the best performing 12% of

sources would be equal to 80-90% or control technology 3 or 4.

The mode would be technology number 4.



Step 4 Select a control technology as the MACT

     Technologies 2, 3, 4, or 5 could be chosen as MACT.  Number

1 could also be consider because its  control efficiency is not

quantifiable.  If the owner wished to consider technology 1, a

more detailed analysis would be required to prove that the

technology could  obtain an equal or greater amount of emission

reductions.  In this case, the efficiency of technology  1 will

vary by the concentration of hazardous  constituents.  Using  clean

water could result  in a less toxic release when the  concentration

of toxins  in the  hot coke are  less, but increased  emissions  could

result with increased concentrations.   The other proposed

technologies would  operate at  a relatively constant  efficiency

rate, regardless  of the pollutant  concentration.   Therefore,

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technology number 1 would be considered inferior and should be

eliminated as a potential candidate.

     The owner or operator should consult with the reviewing

agency to determine whether a costs, non air quality health and

environmental impacts and energy requirements analysis is

required for the available control technologies.  If not, the

owner or operator could select any of these control technologies.

If an analysis is required, the control technology achieving a

maximum degree of reduction in emissions of the HAPs should be

selected based on the costs, non-air quality environmental and

health impacts and energy requirements analysis.  After  selecting

the technology the owner or operator would proceed to Tier III of

the analysis.  In Tier III, the appropriate operation conditions

and design specification would be prescribed in lieu of  a

specific MACT emission limitation.
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                            Example 2

               When the MACT floor  is Determined

                 using Emission Reduction Ratios



Description of Source

     A surface coating operation treats a product with its

existing equipment consisting of a dip-tank priming stage

followed by a two-step spray application and bake-on enamel

finish coat.  The product is a specialized electronics component

(resistor) with strict resistance property specifications that

restrict the types of coatings that may be employed.



Step 1) Identify the MACT-affected emission unit(s)

MACT-affected emission units -     1. dip-tank
                                   2. feed and waste lines in
                                   prime coating operation
                                   3. spray coat booth, spray
                                   coat application equipment
                                   4. drying oven
                                   5. storage tank in prime
                                   coating operation
                                   6. storage tank in finish
                                   coating line


     There are two process units within this source category: the

prime coating line and the finish coating line.  Equipment within

the prime coating line that have affected emission points are a

dip-tank, storage containers,  feed  line to supply new coating

into the dip-tank, a waste line to drain the dip-tank.  Because

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the feed line and waste lines have equipment leak emissions,

these emission points should be combined to form a MACT-affected

emission unit.  The owner or operator will consider the dip-tank

and each storage container a separate affected emission unit.

The three MACT-affected emission units in this process unit are

the dip-tank, the storage container, and the feed and waste

lines.

     The finish coating line consists of two spray booths, spray

application equipment, paint supply system, a storage container,

and a drying oven.  After consulting with the permitting agency,

the owner or operator combines affected emission points to form

the following MACT-affected emission units:  the spray

application equipment and spray booths; the paint supply system,

the storage container, and the drying oven.  For simplicity of

this example, the MACT analysis will be continued for only the

spray application equipment and spray booths.
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Step 2)  Make a MACT floor finding
     Steps A and B:  Computing the Uncontrolled Emissions and
Controlled Emissions
Overview Analysis of emissions information for similar emission
units within the source category:
     Technology               * of sources using
1)   water-based coat              2
2)   low-VOC solvent/high          4
     solids coat

3)   electrostatic  spray           7
     application to enhance
     transfer  efficiency

4)   low  voc solvent/high  solids   8
     coating with electrostatic
     spray application

5)   powder coat paint with        1
     electrostatic  spray
     application

 6)   high-voc  solvent coating      8
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Detailed analysis
Source
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Technology
#
6
3
2
3
3
6
6
3
2
2
6
6
6
3
2
3
4
5
4
3
4
4
Uncontrolled
emissions
(tons/yr)
10
26
48
86
98
26
35
78
69
15
11
12
23
85
141
25
159
126
35
25
68
46
Controlled
emissions
(tons/yr)
10
14
22
56
55
22
34
55
25
11
11
12
22
52
89
20
100
11
14
16
22
10
Emission
reduction
ratio
0
.46
.54
.35
.44
.15
.03
.29
.64
.27
0
0
.04
.39
.39
.20
.37
.91
.6
.36
.70
.78
                            A -  17

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Source
23
24

26
27
28
29
30
Technology
#
1
L_6 	
4
4
4
4
6
1
Uncontrolled
emissions
(tons/yr)
95
96
64
98
168
196
186
255
	 ' 	 > 	 !=
Controlled
emissions
(tons/yr)
10
16
25
31
45
63
186
26
Emission
Reduction
Ratio
.89
.83
.61
.68
.73
.68
0
.90
A -  18

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                                                  Proposal
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     Step C    Computing the Emission Reduction Ratio  for the
               MACT- Affected Emission Unit

     Because there are 30 sources,  the MACT floor should be based

on the arithmetic mean of the emission reduction ratios achieved

by the best 12% of existing emission units.  Twelve percent of 30

emission units is equal to 3.5 sources.  The owner or operator

should round up all fractions to the next largest number.  The

MACT floor would be equal to the arithmetic mean of the emission

reductions obtained by the best 4 sources in the source category.

Reviewing the data above the MACT floor would be equal to an

emission reduction ratio of 0.88 ([0.91 + 0.90 + 0.89 + 0.83]/4)

or the emission reductions that can be achieved when control

technologies 1 or 5 are used.  In this example, the nature of the

product requires a specific type of coating.  Technology  1 and  5

are  inappropriate for application to this MACT-affected emission

unit.  The owner or operator would continue with the analysis to

identify other technologies that can meet  a 0.88 emission

reduction ratio.



      Step D    Determine  a  MACT  emission limitation  (MEL)

      The owner or operator  of  the MACT-affected emission unit

needs to calculate  an uncontrolled  emission rate for the MACT-

af fected emission unit.   Because current design specifications

for  existing emission unit  cause a  larger  uncontrolled emission

rate than  any other designs used in the past  5 years,  the current

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                                                  Proposal
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operational designs will be used to determine the uncontrolled

emissions.  With the existing coating material,  the MACT-affected

emission unit has an uncontrolled emission level of 125 tons/yr

total HAPs.  The MEL for this emission unit would be



          MEL = 125 tons/yr * (1 - 0.88)

              = 15 tons/yr



Step 4    Select a control technology to meet the MACT Emission

          Limitation.

     In this case, the owner or operator must select a control

technology that allows the source to meet the MACT emission

limitation.  Because the owner and operator can not use any of

the identified control technologies to meet the MACT floor,

control technologies to control similar emission points will be

considered.  In this example, the similar emission points have

operational losses.  Review of control technologies to control

operational losses identifies add-on control devises such as a

carbon absorber, a thermal or catalytic incinerator, or a

condenser.  The owner or operator should conduct a costs, non-air

quality health and environmental impacts and energy requirements

analysis  on the available control technologies.

     The  major source already has a catalytic incinerator on

site.  The emissions from the spray application equipment and

spray booth could be channeled to the  incinerator.  This would

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                                                  Proposal
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require the installation of a venting system including a pump

mechanism.  It would also require an increased volumetric flow

rate to the incinerator and increase auxiliary fuel requirements.

The incinerator had been operating at a 90% efficiency.  With an

increased volumetric flow rate, the efficiency is projected to

drop to 87% efficiency.  The owner and operator must obtain an

additional 1% emission reductions.  Possible control technologies

include increasing the operating temperature of the incinerator,

or adding electrostatic application to the spray process to

enhance transfer efficiency.  Limiting the hours of operation at

the MACT-affected emission unit could be considered if the

reduced production were part of an overall source reduction

program.

     Use of the specialized coating in this operation will

increase the concentration of hazardous pollutants in the water

used for the water curtain.  The proposed control technology does

not affect the concentration of pollutants in the wastewater.

This could be considered a negative environmental impact and may

be reason to consider  another control technology to meet the MACT

emission  limitation.   In this instance, the owner or operator

will not violate the NPDES permit, so the MACT candidate will not

be eliminated from consideration.

     The  owner or operator uses this step to demonstrate that

despite the increase in volumetric flow rate and the auxiliary



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                                                  Proposal
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fuel requirement,  a significant increase in CO2 emissions  does

not occur.  The owner or operator concludes that the impacts

associated with use of this technology are reasonable.

     After reviewing the technologies the owner or operator

selects the incinerator with a limit on the hours of operation.

The owner or operator proposes to start a training program for

spray booth operators to decrease the error and product rejection

rate.  By doing this, the owner or operator can reduce the hours

of operation and still meet customer demands for the product.

This option was chosen over the other two because increasing the

incinerator's operating temperature would require additional

auxiliary fuel input, and enhancing the transfer efficiency with

electrostatic application would be cost prohibitive.  The owner

or operator would  document that use of the selected control

technologies can reduce emissions to the required level.

     The  owner or  operator would move to Tier III of  the  analysis

and  document the MACT emission limitation, and suggest

appropriate conditions to  assure that this MACT  emission

limitation is federally enforceable.
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                                                  Proposal
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                            Example 3

          When the MACT floor is Equal to "No Control"



     A commercial treatment storage and disposal facility

receives off-site wastes from various pesticide manufacturers.   A

solvent/aqueous/pesticide mixed waste is passed through a

distillation column where the organic solvents are vaporized and

then condensed into a distillate receiver.   The solvent is

transferred using tank cars to a tank farm that is located at

another portion of the plant.  The low-grade solvent is then sold

to industrial users.   The pesticide-laden wastewater is then

passed through a series of carbon adsorbed where the majority of

pesticide is removed from the water.  The water is then

discharged to a Publically Owned Treatment Works (POTW).   The

carbon adsorbers are periodically steam stripped to regenerate

the carbon.

Step 1) Identify the MACT-affected emission unit(s)

MACT-affected emission units:      1) each storage tank
                                   2) the distillation column,
                                   condenser, and distillate
                                   receiver
                                   3) the three carbon absorber
                                   4) pumps, feed lines and
                                   transfer lines
                                   5) loading racks

     The two process units that contain emission points affected

by this modification are the recycling process, and the tank

farm.  The equipment and apparatus associated with the affected


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                                                  Proposal
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emission points are pumps,  feed lines,  a distillation column,  a

condenser, a distillate receiving tank,  three carbon absorber and

transfer lines, and a loading rack,  and storage tanks.  After

consulting with the permitting agency,  the owner or operator will

consider the three carbon absorbers and the associated emission

points as one emission unit because a single control technology

could be practically design to cover all three affected emission

points.  The owner or operator will also group the distillation

column, distillate receiver and condenser into one MACT-affected

emission unit.  The feed lines, pumps,  and transfer lines would

have equipment leak emission losses and would be another affected

emission unit.  The owner and operator has decided to consider

the emission points and equipment for the loading rack and tanks

as separate MACT-affected emission units.  If all the tanks were

structurally similar in design one determination could be made

that would be  applicable to all the tanks.



Step 2)  Make  a MACT floor finding

     For  simplicity of this example, the MACT analysis will only

be continued for a tank emission unit.  All  the storage tanks

will be structurally similar, so only one MACT determination will

be required.   The manufacture has reviewed existing data  bases

and determined that less than  12% of tanks in the  source  category

are controlled.  Therefore the MACT  floor  is equal to "no

control".  This is not automatically an acceptable  "control"

                           A  -  24

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                                                  Proposal
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measure, so the owner or operator will move to Tier II of the

MACT analysis.  In Tier II of the analysis control technologies

for similar emission points from outside the source category will

also be considered.
Tier II - Step 1 List All Available Control Technologies

     The following technologies have been identified as possible

control technologies that can be applied to a storage tank to

control working and breathing emission losses:

                                                Emission control
                                                  efficiency

     1.  fixed-roof                                    86-99
     2.  fixed-roof plus internal floating roof        97-99
     3.  fixed roof vented to a carbon canister        95-100
     4.  fixed-roof vented to a combustion devise      99-100
     5.  fixed-roof vented to carbon absorber          99-100
     6.  pressure tank                                 95-99


Step 2 Eliminate Technically Infeasible Control Technologies


     All of  the available control technologies are technically

feasible.
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                                                  Proposal
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Step 4 Conduct a Non-air Quality Health, Environmental, Economic

and Energy Impacts Analysis

The following charts illustrates a non-air quality health,

environmental, cost and energy impacts analyses of each control

option.
Control Option
1 fixed roof
2 fixed roof +
internal roof
3 pressure tank
4 cover and
vented to
carbon canister
5 cover and vent
to combustion
devise
cover and vent to
carbon absorber
Secondary Air Impacts
none
none
none
emission if
carbon regenerated
increased CO, NOx,
SOx, and particulate
emissions
emissions when
carbon regenerated
Resource Demands
none
none
none
disposal of
container, solvents
for regeneration
fuel source,
disposal of ash
disposal of spent
carbon, solvents for
regeneration
                            A - 26

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                       Proposal
                       June  1993
Control
Technology


1
2
3
4
5
6
Average
Control
Efficiency
(%)
93
98
98
98
100
100
Emission
Reductions
(Mg/yr)

25
26
26
26
27
27
Capital
Investment
($)

3790
7330
4840
5270
5790
5270
Annual
Cost
($)

760
1870
3560
1020
1080
4230
Average
Cost
Effectiveness
($/Mg)
30
72
137
39
40
157
Incremental
Cost
Effectiveness
($/Mg)

1110
2800
260
60
3210
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                                                  Proposal
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     The manufacturer will chose option 4 as the MACT candidate.

Control technology 1 was eliminated because it had the lowest

control efficiency and the cost, environmental, and energy

considerations did not preclude the use of a control technology

that obtains a greater reduction in emissions.  Control

technologies 2 and 3 were eliminated because control technology 4

is equally efficient in reducing emissions, but has a much lower

cost than technologies 2 and 3.  Technology 5 could have been a

suitable candidate, but the manufacturer eliminated it due to its

secondary air and energy impacts.  Technology 6 has been

eliminated because the capital  investment and annual costs are

high and there are secondary air and other  impacts that are not

outweighed by the emission reductions that  would be obtained.

     The owner or operator will progress to Tier III of the

analysis and determine the degree  of reduction  in emissions of

the HAPs that can be obtained  if the storage  tanks are covered

and vented to a  carbon canister.
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                           Appendix B



                 Forum of Anticipated Questions



1.   When computing the number of sources in the "best 12% or

best 6% of similar sources in the source category" should the

number of sources be rounded to the nearest or next largest whole

number?

For example if there are forty-five similar sources in the source

category would the "best 12%" include 5 or 6 sources.



     The number should be rounded to the next largest number.  In

the example the "best 12%" would include 6 sources.



2.   How many decimal points should be in the emission reduction

ratio, and the manufacturer's efficiency rating?



     The emission reduction ratio should be carried to two

decimal places.  The efficiency rating should be rounded  to  the

nearest whole number.



3.   Should the emission limitation(s) be based on overall HAP

emissions or emissions of an  individual HAP?

     The emission limitation  may be based on  overall  HAP

emissions or a specific emission limitation may be specified for

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an individual HAP.   A specific emission limitation may be

established if health risks warrant placing an individual

emission limitation, or if an individual emission limitation is

needed to make the overall HAP emission limitation federally

enforceable.



4.   If a major source already complies with a case-by-case MACT

determination under Section 112(j) and it later proposes to

constructed a new source, and emissions also increase from

existing equipment or apparatus, what type of determination, if

any is done for the existing equipment?



     If the emission increases from the new source are not

     greater than de minimis as defined by 40 CFR Part 63,

     Subpart B, the owner or operator would be require to meet a

     new source level of control, but would not be required to

     apply  for any preconstruction review, unless such a review

     is required  by the  individual permitting agency.  If the

     emissions increases are above de minimis, the construction

     may constitute a modification, construction or

     reconstruction of a major source as  defined in  40 CFR  Part

     63, Subpart  B.  If  this is the case,  a notification  of the

     construction or a preconstruction  review may be required.



 5.   A  non-major  source  undergoes a construction, reconstruction

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or modification and increases emissions above  a de minimis

amount.  This emission increase reclassifies the source as a

major source for which the source category is subject to a

Section 112(j) determination.  What type of MACT determination

would be required for the source.



     The entire source category at the major source would be

     subject to a Section 112(j) determination and would need to

     immediately apply for a Title V permit application

     reflecting a MACT emission limitation on all affected

     emission points within the source category.  A permitting

     agency may also require that the owner or operator obtain a

     Notice of MACT Approval before the construction or

     reconstruction.  Any emission points subject to the

     modification provisions of Section 112(g) would require the

     affected emission units to obtain a Notice of MACT Approval

     through the Section 112(g) process before beginning

     construction of the modification.



6.   Must MACT always be an  add-on control  devise?

     No.  MACT is a control  technology which  can  include  add-on

     controls, work practices,  pollution prevention methods, etc
 7.   A major  source  has  agreed  to participate  in  the  volunteer

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                                                  Proposal
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emission reductions program pursuant to Section 112 (i) (5) of the

Act.  Through this program, an owner or operator of a major

source can obtain a compliance extension for a future MACT

standard, if a 90% reduction in emissions is achieved before

promulgation of that relevant emission standard.  Is this source

subject to a Section 112 (j) MACT determination.



     In order to avoid a case-by-case MACT determination under

     Section 112 (j), the source must have obtained the required

     level of emission reductions by the promulgation deadline

     for the relevant source category.  If the source has met the

     required level of reduction, it is still required to apply

     for a Title V permit  to incorporate the alternate emission

     limitation  into the permit unless such limit  is  already in a

     Title V permit.  If the alternate emission limitation  has

     not been achieved by  the promulgation deadline a case-by-

     case MACT determination would  be required under  Section
 8.   In  the  course  of  conducting  a  MACT analysis  for a Section

 112 (j)  Title V permit application,  the owner  or  operator

 discovers that the MACT floor is equal to 97% control.   Could the

 owner or operator  enter the early  reductions  program and only

 obtain  90%  control?
                            B -

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                                                  Proposal
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     If the promulgation deadline for a  source  category has  been

     missed,  the source is no longer eligible for the early

     reductions program.



9.   If a State develops a general permit applicable to certain

emission units in a source category, is  an owner or operator

required to apply for the general permit rather than a  specific

Title V permit?

     No.  Using available information, the owner or operator

     could prepare an application for a  specific Title  V permit

     rather than apply for the general permit.



10.  If a State has conducted a MACT analysis which is provided

to the owner or operator, is the owner or operator required to

use the results of this MACT analysis?

     Unless, the State has passed a  specific State law using the

MACT analysis, an owner or operator  is not required to rely on

the State MACT analysis.  However,  the owner or  operator is

required to prepare an  application  using all available

information.  This would  require the source to use the

information the State used to conduct the MACT analysis.

Additional  information  could be  added to the application, if  it

is publically  available,  accurate  and reliable.
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                           DEFINITIONS
Act - the Clean Air Act as amended in 1990 (42 U.S.C. 7401 et seq..
as amended by Pub. L. 101-104 Stat. 2399).

Administrator - the United States Environmental Protection Agency
or his or her authorized representative  (e.g a State that has been
delegated the authority to implement the  provisions of this part.)

Affected  emission point - an emission point  identified as being
part  of  a  modification,  construction  or  reconstruction  and
requiring a MACT determination.

Alternative test method - any method of sampling and analyzing for
an air pollutant that  is not  a  test method in 40 CFR Part 63 and
that  has been demonstrated to  the Administrator's satisfaction,
using Method 301 in  Appendix A of Part 63,  to  produce results
adequate  for the Administrator's determination that it may be used
in place  of a test method specified in that part.

Approved  permit program - a  State  permit program approved by the
Administrator as meeting  the  requirements of 40 CFR Part 70, or a
federal  permit program  established under 40 CFR Part 71.


Controlled emissions - the sum of all  hazardous air emissions from
all emission points given the maximum  design capacity currently  in
use by the emission unit taking into consideration the application
of  all   existing  control technologies and  federally enforceable
limits.

Control  technology  -  measures, processes  method,  systems,  and
techniques  to  limit the  emission of  hazardous  air   pollutants
including, but not limited to,  measures  which

      (1)  reduce the volume  of, or eliminate  emissions of, such
      pollutants through process changes,  substitution or materials
      or  other modifications,

      (2)  enclose  systems or processes to eliminate emissions,

      (3)  collect,  capture or treat such pollutants when released
      from a  process,  stack,  storage or fugitive  emissions point,

      (4)  are design,  equipment work practice,  operational standards
      (including    requirements    for   operator   training    or
      certification)  as  provided in subsection  (h), or

      (5)  are a  combination of above.

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Commenced  -  with  respect  to  construction,  reconstruction  or
modification of a stationary source, that an owner or operator has
undertaken a continuous program of construction, reconstruction or
modification  or that  an  owner or  operator has  entered  into  a
contractual  obligation  to  undertake  and  complete,  within  a
reasonable   time,   a  continuous   program   of   construction,
reconstruction, or modification.

Compliance  date  -  the date  a  MACT-affected  emission unit  is
required to be  operating and meeting  all  the requirements of the
Notice of MACT Approval. For new sources this date is upon start-
up.    For  existing  sources  this  date  should  be   as  soon  as
practicable, but no later than  3 years from the effective date, or
as otherwise specified by a relevant emission standard.

Construct - to fabricate (on site), erect, or install a stationary
source  which  is  or may be subject  to a  standard,  limitation,
prohibition, or other federally enforceable requirement established
by the  Administrator  (or a  State  within approved permit program)
pursuant to Section 112 of the Act.


Continuous emission monitoring system  (GEMS) - the  total equipment,
meeting the data acquisition and availability requirements  of this
part,  used to  sample, condition  (if applicable),  analyze,  and
provide a permanent record of emissions.

Continuous  monitoring  system  (CMS)   -  a  continuous  emission
monitoring system or a continuous parameter monitoring system.


Effective date  - the date a Notice of MACT Approval is signed and
issued  by  a  permitting  agency,  or  the  date  specified  in  a
promulgated emission standard.

Emission Unit  - one emission  point  or the collection of emission
points within a major  source requiring a MACT determination.
An emission unit  can  be defined  (by the permitting authority) as
any of the following:
           (1)  An   emitting  point   that   can   be   individually
controlled, e.g. a  boiler, a spray booth, etc.
           (2)   The smallest grouping of emission points, that, when
collected together, can be commonly  controlled by  a single  control
device  or work  practice.
           (3)   A grouping of emission  points, that, when collected
together, can be commonly controlled by a  single control device or
work practice.
           (4)   A grouping of emission  points that  are  functionally

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                                                  Proposal
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related. Equipment  is functionally related  if the  operation or
action for which the equipment was specifically designed could not
occur without being connected with or relying on the operation of
another piece of equipment.
           (5)  A grouping of emission points that, when collected
together,   comprise   a    building,   structure,   facility,   or
installation.

Existing   Source   -  a  source   that  is  not   constructed  or
reconstructed.

Federally  enforceable -  all limitations and conditions which are
enforceable  by the  Administrator,  including  those  requirements
established by State or Local agencies who have received delegation
to  impose  such  limitations  through  an  approved Part  70 permit
program  or  through Section  112(1)   of  the  Act.   Requirements
developed  pursuant  to Part  60  and Part  61  of this  chapter and
requirements within any  applicable  State Implementation Plan are
also   considered   federally  enforceable.     To   be  federally
enforceable, the limits and conditions must undergo public review
and be  reported  to  the  EPA.   Emission limits that are considered
federally  enforceable include limits  on the allowable capacity of
the  equipment;  requirements for the  installation,  operation and
maintenance  of pollution control technologies; limits on hours of
operation;  and restrictions on  amounts  of  materials combusted,
stored  or  produced.  To be federally  enforceable, restrictions on
operation,  production  or  emissions  must  reflect  the  shortest
practicable  time period  (in no event  for  a period in excess  of 30
days.)   General  limitations  such as yearly limits (e.g. tons per
year) are not considered  federally enforceable.  The use of hourly,
daily,  weekly,  or monthly rolling  averages  are  acceptable.  Any
federally  enforceable limitations or conditions must be practically
enforceable   and   ensure   adequate  testing,   monitoring,  and
recordkeeping  to demonstrate compliance with the limitations and
conditions.
Fugitive emissions - emissions from a stationary source that could
not  reasonably pass  through  a  stack,  chimney ,  vent or  other
functionally  equivalent  opening.

Hazardous Air Pollutant (HAP) - any air pollutant listed in Subpart
C  of  40 CFR Part  63 pursuant to Section 112(b) of  the  Act.   When
there is a discrepancy between the hazardous air pollutant list in
Section 112 (b)  and the list  in  Subpart  C,  the list in  Subpart C
shall supersede the  list in  Section  112(b).

Maximum achievable control technology fMACT)  - a control technology

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                                                  Proposal
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that achieves a  maximum  degree of reduction in  emissions of the
hazardous  air pollutants  with  consideration  to the  costs  of
achieving such emission reductions, and the non air quality health
and environmental impacts and energy requirements.

MACT-affected emission unit - an emission unit or source requiring
a MACT determination.

MACT analysis -  the  process  an owner/operator  conducts  to define
the MACT floor,  recommend  a  MACT  emission  limitation,  and select
the MACT.

MACT determination -  a process conducted by  the Administrator to
evaluate a major source's ability to comply with the requirements
of 40 CFR Part 63, Subpart B.


MACT emission  limitation (MEL) - the maximum  achievable control
technology emission  limitation for the hazardous  air pollutants
listed under Section 112(b) of the Act that the Administrator  (or
a  State with an approved permit  program)  determines  through  a
promulgated emission standard or on a case-by-case basis to be the
maximum  degree  of  reduction  in emissions  of  the  HAPs  with
consideration to the costs of achieving  such emission reductions
and the non air quality health and environmental  impacts and energy
requirements.
     If the Administrator or  reviewing agency determines  that  it is
inappropriate to prescribe a  numerical or efficiency based MACT
emission limitation  a specific design,  equipment,  work practice,
operational  standard,  or combination thereof,  may  be prescribed
instead.   Such standard  shall, to the  degree possible,  set forth
the  emissions reduction  achievable  by  implementation  of  such
design, equipment, work practice, or operation, and shall provide
for compliance by means which  achieve equivalent results.

MACT floor - for new sources or constructed or reconstructed major
sources: a level of  hazardous  air pollutant emission control that
is achieved  in practice  by the best  controlled similar source as
determined by the Administrator.

     For a existing sources or a modification to a major  source the
MACT floor is:
     (a)  the  average emission  limitation  achieved  by  the best
          performing 12 percent of existing sources  (for which the
          Administrator has emission information), excluding those
          sources that have,  within  18 months before the  emission
          standard  is proposed or  within  30 months  before such
          standard   is  promulgated,   whichever  is  later,   first
          achieved a  level of emission rate or emission  reductions

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                                                  Proposal
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          which compiles,  or  would comply  if  the source  is  not
          subject to  such standard, with  the lowest  achievable
          emission rate  (as  defined by  Section  171 of  the  Act)
          applicable to the source category and prevailing at the
          time, in the category or subcategory for categories and
          subcategories with 30 or more sources;  or,
     (b)   The  average  emission limitation  achieved by  the  best
          performing 5 existing sources for  sources with less than
          30 sources in the category or subcategory.
Ma-ior source - any stationary source or group of stationary sources
located within  a contiguous area  and under common  control that
emits or  has the potential to emit considering  controls,  in the
aggregate, 10 tons per year or more of  any hazardous air pollutant
or 25 tons  per  year or more of  any combination  of hazardous air
pollutants, unless the Administrator establishes  a  lesser quantity
as codified  in  Subpart C  of  40 CFR Part  63,  or  in  the  case of
radionuclides,   different  criteria from  those specified  in this
sentence.
Notice of MACT Approval - a document issued by a reviewing agency
containing  all  federally  enforceable  conditions  necessary  to
enforce  the  application of, and operation of  MACT  such that the
MACT emission limitation is met.

Owner  or  operator  -  any  person  who  owns,   leases,  operates,
controls, or supervises a stationary source.


Part 70 permit - any permit  issued, renewed, or revised pursuant to
40 CFR Part  70.

Part 71  permit  - any permit issued , renewed,  or revised pursuant
to Part  71 of this  chapter.

Permit program - a comprehensive State or Federal operating permit
system established pursuant to regulations codified in 40  CFR Part
70 or Part 71.

Permit revision - any permit modification or administrative permit
amendment to a Part 70 or Part 71 permit as defined in those parts.

Promulgation deadline - for each source category the date by  which
EPA  is  required  to establish emission  standards  for  the source
category in accordance with Section 112(c)  of the Act.  These  dates

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are published in a regulatory schedule in the Federal Register.

Potential to emit - the maximum capacity of a stationary source to
emit a pollutant under its physical  and  operational  design.   Any
physical  or  operational  limitation  of  the  capacity  of  the
stationary  source  to emit a  pollutant,  including air  pollution
control equipment and restrictions on hour of operation or on the
type or amount of material combusted, stored, or processed, shall
be treated as part  of its design if the limitation or the effect it
would have on emissions is federally enforceable.

Project   -   all   activities   associated   with   construction,
reconstruction,  or modification  of   a  source  including  design,
fabrication, erection,  installation and start-up.

Reconstruction - the replacement of components of an existing major
source to such an extent that (1)  the fixed capital cost of the new
components exceeds 50 percent of the  fixed capital cost that would
be required to construct  a comparable entirely new source, and (2)
it   is   technologically   and   economically  feasible   for   the
reconstructed   source  to  meet  the  Section   112(d)   emission
standard(s),  alternative  emission  limitation(s), or equivalent
emission  limitation(s)  established  by the  Administrator  (  or  a
State with an approved permit program) pursuant to Section 112 of
Act.  Upon reconstruction,  an affected source is  subject to Section
112(d)  standards  for  new sources,  including  compliance dates,
irrespective of any change in emissions of hazardous air pollutants
from that source.

Relevant  standard  - (1)  an emission  standard,   (2) an alternative
emission  standard,  (3)  an alternative emission  limitation, (4) an
equivalent emission limitation that applies  to a stationary source
regulated by such standard or limitation.  A relevant  standard may
include  or  consist of  a design,   equipment  work  practice,  or
operational requirements or other measures, process, method, system
or  technique   (including  prohibition  of   emissions)  that  the
Administrator   (or  a  State  with an approved  permit  program)
determines  is achievable  for a constructed or reconstructed major
source, new or existing source to which such standard  or limitation
applies.  Every  relevant  standard established pursuant to  Section
112 of the Act  includes Subpart A of  this part  and all applicable
appendices of Parts 51,  60, 61, and 63 of Chapter 40 of the code of
federal  regulations that  are reference in that  standard.

Similar  emission unit - two or more sources  or emission units that
have  similar emission types  and  can  be controlled using the same
type  of  control  technology.

Similar  emission type -  See Section  2.4 of  Chapter 2.

                             C - 6

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                                                  Proposal
                                                  June 1993

Source  - an  emission  unit,   or  as  otherwise  specified in  an
applicable 40 CFR Part 63 emission standard.

Start-up - beginning operation of a source or emission unit.

State -  all  non-federal permitting authorities,  including local
agencies, interstate associations,  and  State-wide programs,  that
have delegated authority to implement  (1)  the provisions of 40 CFR
Part 63; and/or (2) the permit program established under Part 70 of
this  chapter.   State shall  have its conventional  meaning where
clear from the context.

Stationary   source   -   any  building,   structure,   facility  or
installation that emits  or may emit any  air pollutant.   For the
purposes  of  40  CFR  Part  63,  stationary  sources are  listed  in
categories pursuant to Section 112(c)  of the ACT and published in
the Federal Register. (See Appendix D)

Uncontrolled emissions - the annual sum of hazardous air pollutant
emissions  that could be  emitted from  all emission points  at a
source  in  the  absence of  control technologies given  the maximum
design capacity used by  the source within the past five  year period
proceeding the date of the proposed construction,  reconstruction or
modification.
                             C - 7

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                          Appendix D
          Initial List of Categories of Major and Area
               Sources of Hazardous Air Pollutants
Fuel Combustion

Category Name
     Engine Test Facilities
     Industrial Boilersb
     Institutional/Commercial Boilers"
     Process Heaters
     Stationary Internal Combustion Engines*

Non-Ferrous Metals Processing

Category Name
     Primary Aluminum Production
     Secondary Aluminum Production
     Primary Cooper Smelting
     Primary Lead Smelting
     Secondary Lead Smelting
     Lead Acid Battery Manufacturing
     Primary Magnesium Refining

Ferrous Metals Processing

Category Name
     Coke By-Product Plants
     Coke Ovens:  Charging, Top Side, and Door Leaks
     Coke Ovens:  Pushing, Quencing, and Battery Stacks
     Ferroalloys Production
     Integrated Iron and Steel Manufacturing
     Non-Stainless Steel Manufacturing - Electric Arc
       Furnace  (EAF) Operation
     Stainless Steel Manufacturing-Electric Arc
       Furnace  (EAF) Operation
     Iron Foundries
     Steel  Foundries
     Steel  Pickling-HCI Process

Mineral Products Processing

Category Name
     Alumina Processing
     Asphalt/Coal Tar  Application-Metal  Pipes
     Asphalt Concrete  Manufacturing
     Asphalt Processing
     Asphalt Roofing Manufacturing
     Chromium  Refractories Production
     Clay  Products  Manufacturing
                            D-l

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     Lime Manufacturing
     Mineral Wood Production
     Portland Cement Manufacturing
     Taconite Iron Ore Processing
     Wool Fiberglass Manufacturing

Petroleum and Natural Gas Production and Refining

Category Name
     Oil and Natural Gas Production
     Petroleum Refineries-Catalytic Cracking
       (Fluid and other) Units, Catalytic
       Reforming Units, and Sulfur Plant Units
     Petroleum Refineries-Other Sources
       Not Distinctly Listed

Liquids Distribution

Category Name
     Gasoline Distribution  (Stage 1)
     Organic Liquids Distribution (Non-Gasoline)

Surface Coating Processes

Category Name
     Aerospace Industries
     Auto and Light Duty Truck  (Surface Coating)
     Flat Woods Paneling (Surface Coating)
     Large Appliances  (Surface  Coating)
     Magnetic Tapes  (Surface Coating)
     Manufacture of Paints  Coatings, and Adhesives
     Metal Can  (Surface Coating)
     Metal Coil  (Surface Coating)
     Metal Furniture  (Surface Coating)
     Miscellaneous Metal Parts  and  Products
        (Surface Coating)
     Paper and Other Webs  (Surface  Coating)
     Plastic Parts and Products (Surface Coating)
     Printing Coating,  and  Dyeing of Fabrics
     Printing/Publishing  (Surface Coating)
     Shipbuilding and  Ship  Repair  (Surface Coating)
     Wood Furniture  (Surface Coating)

Waste Treatment  and  Disposal

Category Name
     Hazardous Waste Incineration
     Municipal  Landfills
     Sewage  Sludge  Incineration
     Site Remediation
                           D-2

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     Solid Waste Treatment,  Storage and
       Disposal Facilities (TSDF)
     Publicly Owned Treatment Works (POTW)  Emissions

Agricultural Chemicals Production

Category Name
     2.4-D Salts and Esters Production
     4-Chloro-2-Methylphenoxyacetic Acid Production
     4.6-Dinitro-o-Cresol Production
     Captafol Production
     Captan Production
     Chloroneb Production
     Chlorothalonil Production
     Dacthal (tm) Production
     Sodium Pentachlorophenate Production
     Tordon (tm) Acid Production

Fibers Production Processes

Category Name
     Acrylic Fibers/Modacrylic Fibers Production
     Rayon Production
     Spandex Production

Food and Agricultural Processes

Category Name
     Baker's Yeast Manufacturing
     Cellulose  Food Casing Manufacturing
     Vegetable  Oil Production

Pharmaceutical  Production Processes

Category Name
     Pharmaceutical Production

Polymers and Resins Production

Category Name
     Acetal Resins  Production
     Acrylonitrile-Butadiene-Styrene Production
     Alkyd Resins Production
     Amino Resins Production
     Boat  Manufacturing
     Butadiene-Furfural Cotrimer (R-ll)
     Butyl Rubber Production
     Carboxymethylcellulose Production
     Cellophane Production
     Cellulose Ethers Production
     Epichlorohydrin Elastomers Production
     Epoxy Resins Production
                              D-3

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    Ethylene-Propylene Elastomers Production
    Flexible Polyurethane Foam Production
    Hypalon  (tm) Production
    Maleic Anhydride Copolymers Production
    Methylcellulose Production
    Methylcellulose Production
    Methyl Methacrylate-Acrylonitrile-Butadiene-
       Styrene Production
    Methyl Methacrylate-Butadiene-Styrene Terpolymers
       Production
    Neoprene Production
    Nitrile Butadiene Rubber  Production
    Non-Nylon Polyamides Production
    Nylon 6 Production
    Phenolic Resins Production
    Polybutadiene  Rubber Production
    Polycarbonates Production
    Polyester Resins Production
    Polyethylene Teraphthalate Production
    Polymerized Vinylidene  Chloride  Production
    Polymethyl  Methacrylate Resins Production
    Polystyrene Production
    Polysulfide Rubber Production
    Polyvinyl Acetate Emulsions  Production
    Polyvinyl Alcohol Production
    Polyvinyl Butyral Production
    Polyvinyl Chloride and  Copolymers Production
    Reinforced  Plastic Composites Production
     Styrene-Acrylonitrile Production
     Styrene-Butadiene Rubber  and Latex Production

Production of Inorganic Chemicals

Category Name
     Ammonium Sulfate Production-Captrolactam
       By-Product Plants
     Antimony Oxides Manufacturing
     Chlorine Production
     Chromium Chemicals Manufacturing
     Cyanuric Chloride Production
     Fume Silica Production
     Hydrochloric Acid Production
     Hydrogen Cyanide Production
     Hydrogen Fluoride Production
     Phosphate Fertilizers Production
     Phosphoric Acid Manufacturing
     Quaternary Ammonium Compounds Production
     Sodium Cyanide Production
     Uranium Hexafluoride Production
                              D-4

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Production of Organic Chemicals

Category Name
     Synthetic Organic Chemical Manufacturing

Miscellaneous Processes

Category Name
     Aerosol Can-Filling Facilities
     Benzyltrimethylammonium Chloride Production
     Butadiene Dimers Production
     Carbonyl Sulfide Production
     Chelating Agents Production
     Chlorinated Paraffins Production
     Chromic Acid Anodizing
     Commercial Dry Cleaning (Perchloroethylene)
       Transfer Machines
     Commercial Sterilization Facilities
     Decorative Chromium Electroplating
     Dodencanedioic Acid Production
     Dry Cleaning (Petroleum Solvent)
     Ethylidene Norbornene Production
     Explosives Production
     Halogenated Solvent Cleaners
     Hard Chromium Electroplating
     Hydrazine Production
     Industrial Dry Cleaning (Perchloroethylene)
       Transfer Machines
     Industrial Dry Cleaning (Perchloroethylene)
       Dry-to-Dry Machines
     Industrial Process Cooling Towers
     OBPA/1,3-Diisocyanate Production
     Paint  Stripper Users
     Photographic Chemicals Production
     Phthalate Plasticizers Production
     Plywood/Particle  Board Manufacturing
     Polyether Polyols Production
     Pulp and Paper Production
     Rocket Engine Test Firing
     Rubber Chemicals  Manufacturing
     Semiconductor Manufacturing
     Symmetrical Tetrachloropyridine Production
     Tire Production
     Wood Treatment
                             D-5

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