United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA 453/R-94-026
May 1994
Air
Guidelines for MACT
Determinations under
Section 1120
FINAL
-------
Final
May 1994
Table of Contents
Introduction iv
Chapter 1.0 An Overview of the MACT Determination Process... 1
1.1 Overview of Statutory Requirements 1
1.2 Overview of the Regulatory Requirements.... 4
1.3 Administrative Review Process for New
Emission Units 6
Chapter 2 . 0 The MACT Determination 13
2.1 Criteria for the MACT Determination 13
2.2 Compliance Provisions 26
2.3 Approaches to the MACT Determination 19
2.4 Available Control Technologies 22
2.5 General Permits...."... 25
Chapter 3 .0 The MACT Analysis 26
3.1 Overview of the MACT Analysis Process 27
3.2 A Detailed Look at the MACT Analysis 31
3.3 Determining the MACT-Affected
Emission Unit 39
3.4 Similar Emission Units 45
3.5 Subcategorization 50
Chapter 4.0 The MACT Floor Finding 51
4.1 Calculation of the MACT Floor 53
4.2 Method 1- Computing the MACT floor
using existing State and Local
Regulations 60
4.3 Method 2 - Computing the MACT Floor
using Control Efficiency
Ratings 65
4.4 Method 3 - Computing the MACT Floor
using Emission Reduction Ratios
(ERR) 67
4.5 Other Methods to Compute the MACT
Floor 71
Chapter 5.0 The MACT Emission Limitation 72
5.1 Using Control Efficiencies to
establish the MACT Emission
Limitation 73
5.2 Using the Emission Reduction Ratio
to establish the MACT
Emission Limitation 76
5.3 Additional Control Requirements 76
-------
Chapter 6.0
Final
May 1994
Costs, Non-Air Quality Health and Environmental
Impacts and Energy Requirements 79
6.1 Costs Impacts 81
6.2 Environmental Impacts 84
6.3 Energy Requirements 86
Chapter 7.0
Sources of Information.
,88
References
Appendix A
Appendix B
Appendix C
,98
Examples of MACT Analyses A-l
Definitions B-l
x»
List of Major Source Categories C-l
11
-------
Final
May 1994
LIST OF FIGURES
Figure 1 Example Notice of MACT Approval 9
Figure 2 The MACT Analysis 28
Figure 3 Using State or Local Air Pollution
Regulations to Compute the MACT Floor 61
Figure 4 Evaluation of State Regulations
for Emission Unit X : 63
Figure 5 Using Emission Reduction Ratios
to Compute the MACT Floor 68
111
-------
-------
Final
May 1994
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 as amended in 1990 (the
Act). 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 is 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 provides a detailed discusion on determine the
minimum level of control that can be applied to a source (the
MACT floor). Chapter 5 briefly discusses some calculation
procedures for the equivalent (MACT) emission limitation.
Chapter 6 describes the analysis that may be required to assess
iv
-------
Final
Hay 1994
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 7
discusses the national databases that may assist in the
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.
-------
Final
May 1994
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 revise 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
was established through the regulatory schedule in accordance
with Section 112(e) of the Act. A final regulatory schedule was
published on December 3, 1993 in the Federal Register
(58 FR 63941).
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
-------
Final
May 1994
source category that becomes subject to the provisions of Section
112(j). The MACT emission limitation will be "equivalent" to the
emission limitation that the source category would have been
subject had a relevant standard 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
2
-------
Final
May 1994
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.
X*
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.
3
-------
Final
May 1994
1.2 Overview of the Regulatory Requirements
The owner or operator of a major source is required to apply
for a Title V permit, when the promulgation deadline for a *
relevant Section 112(d) or Section 112(h) emission standard is
missed. For existing sources, the permit application must be
received by the permitting agency no later than 18 months from
the date that the promulgation deadline is missed (the Section
112(j) deadline or "hammer date"). For new sources, this permit
application must be received within 12 months after commencing
operation, but not sooner than the Section 112(j) deadline.
Section 63.53 of Chapter 40 of the Code of Federal Regulations
lists the information required for a complete permit application
submittal.
In addition to the requirement to submit a permit
application, EPA also recommends that an owner or operator of a
proposed new or reconstructed source be required to obtain a
Notice of MACT Approval. This recommendation is discussed in
greater detail in Section 1.3 of this chapter.
Ideally, the Administrator or permitting agency will notify
the major source of a projected source category equivalent
emission limitation based on a preliminary assessment of the MACT
floor finding and the MACT before the Section 112(j) deadline.
When such information is made available to the source before this
deadline, the permit application must demonstrate how the major
source will achieve the projected level of control. The
4
-------
Final
May 1994
applicant may also chose to include an analysis that supports an
alternate level of control. This information should be
considered by the permitting agency before final issuance of the
Title V permit. Applicants who wish to support an alternate
level of control should refer to the guidance contained in
Chapters 3 and 4 to develop such an alternative.
If the Adminsitrator or permitting agency fails to provide
the source with a projected equivalent emission limitation before
N»
the Section 112(j) deadline, the applicant is not required to
include a control technology demonstration in the complete permit
application submittal. Once the permitting agency determines the
level of control required for the source category, the permitting
authority may request additional information from the applicant
at that time. The applicant should supply this information to
the permitting agency as expeditiously as practicable.
-------
Final
May 1994
1.3 Administrative Review Process for New Sources
Some owners or operators may be required to obtain a Title V
permit revision if a source's existing Title V permit prohibits
the construction of a new source or reconstruction of an existing
source without first obtaining a permit revision. However, 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
x*
construction, the source is not required to apply for a Title V
permit until 12 months after operation. It may take upto an
additional 18 months before an approved permit is issued. This
delay between the actual construction date and permit issuance
date can create problems for both the permitting agency and the
major source. In recognition of these potential
problems, Subpart B of 40 CFR Part 63 allows a permitting agency
to include a preconstruction review process as part of its
Section 112(j) program. This process would require owners and
operators of major sources to undergo preconstruction review
before constructing a new source or reconstructing an existing
source, if construction is to commence after the Section 112(j)
deadline.
Providing for a preconstruction review process under such
circumstances is advantageous for both the major source and the
permitting agency. Because of the different requirements of
Section 112.(j) and Section 112 (g) of the Act, a source may be
6
-------
Final
May 1994
required to undergo a preconstruction review under Section 112(g)
if it proposes to modify, construct or reconstruct the major
source. If Section 112(g) considers the change at the major
source to be a modification, the source would only be required to
comply with an existing source MACT level of control. The same
activity at the major source may also qualify as construction of
a new source under Section 112(j). It is then required to meet a
new source level of control. A preconstruction review program
under Section 112(j) would allow for early recognition of such
overlaps and ensure that the major source is taking proper action
to comply with the more stringent requirement. In addition, it
provides the source with an opportunity to interact with the
permitting agency before construction to build proper controls
into the upfront designs and avoid the need to retroactively fit
state of the art controls.
As part of the preconstruction review process, the
permitting agency could issue the major source a Notice of MACT
Approval. This notice serves as a mechanism to ensure federal
enforceability of the requirements established during the
preconstruction review before such requirements are incorporated
into the Title V permit. If the preconstruction review process
meets the substantive requirements of Title V, the requirements
of the Notice of MACT could be incorporated into the Title V
permit through administrative amendment. Section 63.54 of
Subpart B explains the necessary elements of a pre-construction
7
-------
Final
May 1994
review process to convey federal enforceability and allow the
requirements in the Notice of MACT Approval to be
administratively amended into the Title V permit. Figure 1
provides a suggested format for the Notice of MACT Approval.
-------
Final
May 1994
air pollutant.
In addition to specifying the MACT emission limitation, the
the permit should establish the terms and conditions that are
necessary 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
X*
provisions in greater detail.
15
-------
-------
Final
May 1994
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
x»
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 to assure that the blanket emission limitation
can not be violated through normal operations.
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-
on control, operating parameters and assumptions that can be used
16
-------
Final
May 1994
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 (CEM) or other periodic
montioring that yields sufficiently reliable data to determine
the source's compliance with the MACT emission limitation. Such
monitoring may be instrumental or non-instrumental and may
consist of recordkeeping designed to serve as monitoring.
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
17
-------
Final
May 1994
daily quantities and the HAP content of each coating used.
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.
X-
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.
18
-------
Final
May 1994
2.3 Approaches to the MACT Determination
When the Administrator fails to promulgate a standard by the
promulgation deadline, the EPA intends to make all non-
confidential information collected during the development of a
source category standard available to the public. If the
Administrator has conducted a MACT floor finding, this analyze
will be made available as well. Information will be conveyed
N«-
either through a Federal Register notice, a background
information document, the Technology Transfer Network (TTN), MACT
database or other available mechanism.
A permitting agency could use several different approaches
for the MACT determination process. An agency could wait until
all applications for permits are received to determine the
equivalent emission limitations that would apply to all of the
sources. Or, an agency or a group of agencies could conduct a
"MACT analysis" based on available information before the Section
112(j) deadline.
The first approach requires less upfront coordination on the
part of the permitting agency and is likely to be used when EPA
fails to collect sufficient information on the source during the
standards development process. Once the permit applications are
received, information from each application can be compiled to
determine the appropriate emissions control level. When this
approach is used, EPA strongly encourages different permitting
19
-------
Final
May 1994
agencies to share information received through the permit
application process. For some source categories, permit
application information may be downloaded into the MACT database
after the Section 112(j) deadline. After the appropriate level
of control is determined using the permit application
information, several permit applicants may need to submit
additional information to demonstrate how the source will meet
the required emission reductions.
x»
The second approach conveys information to an applicant
before the initial application submittal. This approach is most
likely to be used when there is a substantial amount of
information already available for a source category, or when EPA
has already proposed standards for that source category. Based
on this available information, the permitting agency (or
coalition of permitting agencies) would conduct a MACT analysis
(See Chapter 3) to determine the appropriate level of control for
each source. This control level could be made federally
enforceable for all sources in the category through the use of
general permits, or each applicant could undergo a separate
review in the Title V permitting process. Section 2.5 discusses
the concept of general permits in greater detail.
Regardless of the approach taken to issue or revise Title V
permits under Section 112(j), permitting agencies are reminded
that the equivalent emission limitation is to be determined on a
case-by-case based for each source category for which a Section
20
-------
Final
May 1994
112(j) MACT determination is required. This determination should
be viewed as a "source category-by-source category"
determinations and terms and conditions in each permit issued
should yield an essentially equivalent degree of emission
reductions for all major source in the category.
21
-------
Final
May 1994
2.4 Available Information
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 had an applicable Section 112(d)
or Section 112(h) emission standard 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 6), 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 EPA provides the permitting
agency with sufficient information to make the MACT
determination. This information could be made available through
a proposed rule, Federal Register notice, Background Information
Document (BID), the MACT Database, a memo to the permitting
agency, or through another available mechanism.
It is not necessary for the MACT floor to be determined
22
-------
Final
May 1994
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
floor can be determine using this information if it is
representative of the source category. For example, suppose
there are 100 sources in a source category. Control technology X
and Y are generally considered to achieve the greatest amount of
emission reductions among existing sources. Thirty sources in
N-
the category use these technologies. The MACT floor could be
determined based on these technologies, even if information was
not available on the other seventy sources.
23
-------
Final
May 1994
2.5 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
x»
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
24
-------
Final
May 1994
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.
General permits would not be an appropriate mechanism to
issue permit conditions if the terms and conditions necessary to
establish federal enforceability as a legal and practical matter
might vary from source to source within the category. For
instance, if a MACT emission Imiitation restricted emissions from
multiple emission points within the source category and the
number of emission points varied from major source to major
source, a general permit may not be appropriate.
25
-------
Final
May 1994
Chapter 3
The MACT Analysis
For most source categories, the process of determining the
appropriate level of control involves a number of different
determinations. First, the emission points at the major source
that are related to the activities and equipment associated with
a source category must be identified. There may be a number of
emitting activities and equipment at a single major source. In
some cases, not all of these emissions are from a single source
category. Only the emission points associated with the source
category undergoing the Section 112(j) MACT determination are
subject to control through an equivalent emission limitation.
After the scope of the source category is determined, the
emission units within that source category must be identified. A
single source category may have only one emission unit comprised
of all of the emission points; or, it may have several emission
units each comprised of some portions of the total number of
emission points. For each emission unit, the new source MACT and
existing MACT and the cooresponding MACT emission limitations
must be established.
The process by which these determinations are made is termed
the MACT analysis. The following sections of this Chapter
describe a MACT analysis process that EPA has developed to meet
26
-------
Final
May 1994
the requirements of 40 CFR Part 63, Subpart B.
3.1 Overview of the MACT Analysis Process
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 also be determined based on emission reductions
currently being achieved by other controlled emission units.
This is known as a positive MACT floor finding. Other possible
outcomes are that the MACT floor can not be determined, or that
the MACT floor equals "no control". It may not be possible to
calculate a MACT floor 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. A MACT
floor could equal "no control" if a substantial number of sources
within the category are not currently controlling HAP emissions.
In either case, EPA believes that a more detailed analysis is
required in order to determine the appropriate level of control.
Therefore, 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. A MACT floor finding is made during Tier I. Tier II
evaluates all commerically available and demonstrated controls
that could be applied to the emission unit after a negative MACT
27
-------
co
CD
C
H
O
CD
.C
I-
CN
CD
CD
LL
CO " ™
.2 £8 &
0) '-5 |g
D) O . g.-- CD
.C "o S .;= 3 £
*_ r~ o CD c c
CD r= *= J- o> ®
Vl/ f • «-. !._ r— r"
"7-1-77 c/> > "• o E c
SO . C7 •
o 7;O£c«EjQ-t-'CO(D
i C_ co -M.-zro c>«
^ —O^WD-Cm**-^
= 0 "filll-' 1*
»- >SoE^0
Ceo i_ tii
v^,._ jl g fc|.
C LL O E 1
2 i- < . H ' H
CD 0 ^ • £ U 0
^> O jz ^ ^ <" ^
^~" i i ^-l c ^ .—
1 ^^ >» ^ CO M-'S ^*
1 1— £8® "R £
" O g 1 « """J |
CD ^^ ~— "~"
1 "^> - — . •— •• [^^ ^
^-
FINAL
May 1994
C m
0 Q)
'+= «
03 E
Emission Limit
itation (MEL).
leet MEL.
nd recordkeeping parai
|_ £ fc co
O — O D)
c -M C
^ o > t
^ 'w cn o
^ || 2
CD o> jz *
h- ° ? •
D) rl o> •- c
^±f *-* •!-• C O
C < - o ~
•= ^ 2 •- «
-C ^ i: c o
.52 5 § If
— -M o *- Q.
-0 •<= co -g ro
03 .« ., .J2 .ti
•M -Q 0 JD E
CO -g J) w ^
LU « CD to 3
t2 0) LLJ C^
,_ CNI CO ^
^^~
_
s_
CD
i-
28
-------
Final
May 1994
floor finding is made. Tier III uses the information developed
in Tier I or Tier II to establish a MACT emission limitation.
If a positive MACT floor finding is made, it is only
necessary to complete Tier I and Tier III of the MACT analysis.
This analysis compares 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 are equal to or greater than the MACT floor. If
N»
the MACT floor can not be determined or is equal to "no control"
(a negative MACT floor finding), Tier II of the analysis should
be completed.
The purpose of Tier II is to identify all commercially
available and demonstrated 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.
29
-------
Final
May 1994
Once a list of available control technologies is 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
X'
selected as MACT. Once MACT has been selected through either
Tier I or Tier II of the analysis, the permitting agency 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). A design, equipment, work practice or
operational standard, or combination there of, should be
designated as the MACT emission limitation, if it is infeasible,
in the judgement of the permitting agency, to prescribe or
enforce a numerical MACT emission limitation.
If an owner or operator wishes to comply with the MACT
emission limitation using a control strategy other than MACT,
then the Title V permit application should be submitted or
revised to demonstrate that this alternative strategy achieves
the required level of emission reductions.
30
-------
Final
May 1994
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
HAP emission points within the source category. 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
scope of the emission unit should be consistent with the existing
source definition in the proposed emission standard, unless an
alternative can be adequately supported. 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
Using the available information provided by EPA, other
permitting agencies, or the permit applications, a level of HAP
emission control that is equal to the MACT floor for each type of
emission unit undergoing review should be calculated. For new or
reconstructed emission units, the MACT floor (or best controlled
31
-------
Final
May 1994
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.
Chapter 4 discusses three ways to establish a MACT floor:
using (1) State and local regulations, (2) control efficiencies
•\-
and (3) emission reduction ratios. Use of any of these
methodologies to determine the floor depends on the format of
available information. It is possible that a hybrid of these
approaches may be necessary, or none of the methods may be
appropriate given the format of the available information. These
methods are provided in this guidance document to demonstrate the
types of methodologies that would be appropriate for establishing
a MACT floor.
If the MACT floor can not be determined or if it is equal to
"no control", a negative MACT finding is made. Under these
circumstances, Tier I should be discontinued and the permitting
agency should move onto Tier II of the analysis.
Step 3 — Identifying MACT
When a positive MACT floor finding is made, the permitting
agency will need to identify control technologies that reduce HAP
emissions from the MACT-affected emission unit to the maximum
32
-------
Final
May 1994
extent and to a level that is at least equal to the MACT floor.
For emission units requiring a new source level of control,
consideration can be given to transfer and innovative
technologies used to control emissions from other emission units
that may not have met the definition of similar but nevertheless
use technologies that can be applied to the MACT-affected
emission unit.
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. The Act does not provide direction on the signficance
of one consideration to another. EPA believes that it is
inappropriate to provide specific guidance for determining the
amount of consideration that should be given to any one factor.
Such decisions will need to be made based on the information
available at the time of the MACT determination. However, under
no circumstances should the MACT emission limitation be less
stringent than the MACT floor.
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 from 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.
33
-------
Final
May 1994
After completing Tier I, the permitting agency should skip
to Tier II of the analysis.
Tier II - Considering all control technology
Step 1 — List available control technologies
.Using available information, the permitting agency should
N*
develop a list of commercially available 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.
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 eliminated from the list. A technology is generally
considered technically infeasible if there are structural,
design, physical or operational constraints that prevent the
application of the control technology to the emission unit. Cost
to install and maintain the control technology is not considered
a factor in determining technical feasibility.
34
-------
Final
May 1994
Step 3 — Conduct an impacts analysis
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 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
A-
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 control technology(s) that allows for a
maximum degree of HAP emission reductions with consideration to
the costs of achieving such emission reductions, and the non-air
quality health and environmental impacts and energy requirements
should be identified. This is the MACT. See Chapter 6 of this
guidance document for a more detailed discussion on the analysis
of the costs, non-air quality health and environmental impacts,
and energy requirements.
35
-------
Final
May 1994
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 and Reconstructed Sources
under Section 112(j)
This notice establishes federally enforceable maximum
achievable control technology emission limitation(s) and
requirements for Name of major 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 major 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 construction or reconstruction; Describe the
action taken by the owner or operator of the major
source that qualifies as the construction of a new
source or reconstruction of an existing source under
the requirements of 40 CFR Part 63, Subpart B, Sections
63.50-63.56
6. Anticipated commencement date for construction or
reconstruction;
7. Anticipated start-up date of construction or
reconstruction;
-------
Final
May 1994
8. List of the hazardous air pollutants potentially
emitted by MACT-affected emission unit(si; List all
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.
10
-------
Final
May 1994
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
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
11
-------
Final
May 1994
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
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.
12
-------
Final
May 1994
Chapter 2 . 0
The MACT Determination
2.1 Criteria for the MACT Determination
The process of determining 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
Section 112 (d) and Section 112 (h) . These criteria should also be
used when establishing the MACT emission limitation under Section
Permits conditions created through Section 112 (j) of the Act
should require emission reduction that:
1) Are no less stringent than the MACT floor when a MACT
floor can be determined; and,
2) Achieves a maximum degree of HAP emission reduction
with consideration to the cost of achieving such
emission reductions, and the non-air-quality health and
environmental impacts, and energy requirements; and,
3) Limits the quantity, rate or concentration or HAP
13
-------
Final
May 1994
emissions on a continuous basis; or,
3) Designates a specific design, equipment, work practice,
operational standard, or a combination thereof, that
achieves a maximum degree of emission reduction, when
it is infeasible to prescribe a specific numerical
emission limitation.
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), a production
ratio (e.g. 10 Ibs of HAP/100 Ibs of polymer), or as a
concentration limit (e.g. lOppm/w HAP). The MACT emission
limitation could also be a performance standard based on the
expected efficiency of MACT in reducing HAP emissions. For
example, a source may be required to reduce emissions by 90% from
a 1990 baseline. If it is infeasible to prescribe a specific
numerical limitation or reduction efficiency the MACT emission
limitation can also be expressed based on a design, equipment,
work practice, operational standard, or any combination of these.
For example, a permit may require a source to use a high
efficieny spray gun in the coating process.
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 should consider whether it is
appropriate to impose such a limitation on a specific hazardous
14
-------
Final
May 1994
Tier III — Establishing a MACT emission limitation
Step 1 — Establish a MACT emission limitation (MEL)
The MACT emission limitation is based on 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 may
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.
If it is not feasible to establish a specific numerical or
efficiency limitation, then a specific design, process, or
control technology should be designated as the MACT emission
limitation. Chapter 5 of this manual explains several procedures
for calculating the MACT emission limitation.
Step 2 — Select a control technology to meet the MACT emission
limitation
Once the permitting agency determines the MACT emission
limitation, the applicant should be given the opportunity to
36
-------
Final
May 1994
propose a control strategy that allows the emission unit to
obtain the required emission reductions. In many cases, this
will be through the application of the MACT technology. However,
in some cases, the emission unit at the major source may already
be controlled to a some extent with an existing control
technology. 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
x»
emission reductions. For instance, an emission unit may
currently be controlled with a baghouse. The MACT emission
limitation for the emission unit may be based on use of 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. Chapter 5
of this manual discusses how the amount of additional control
that would be required (ARC) can be computed under such
circumstances.
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,
37
-------
Final
May 1994
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 these factors when selecting a control technology to
meet the MACT emission limitation.
X'
Step 3 — Establish appropriate monitoring, reporting and
recordkeeping parameters
The permitting agency should identify monitoring parameters
to assure compliance with the MACT emission limitation. Section
2.2 of Chapter 2 discusses compliance provisions in greater
detail.
38
-------
Final
May 1994
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.
N*
There are four basic principles to follow when designating
the MACT-affected emission unit. The principles can be
summarized as follows: I) When a relevant Section 112(d) or
Section 112(h) standard has been proposed, the permitting agency
should refer to the relevant standard to determine the MACT-
affected emission unit; or, (2) The EPA's Office of Air Quality
Planning and Standard's should be consulted to determine if a
suggested method for grouping affected emission points is
available ; or, (3) When a specific piece of equipment is
designated as a source category on the source category list, the
MACT-affected emission unit is that piece of equipment or
apparatus; 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
39
-------
Final
May 1994
after the promulgation of a relevant standard is found in a
proposed standard. For this reason, EPA believes that permitting
agencies should follow the guidelines in the proposed standard to
determine the MACT-affected emission unit for a Section 112(j)
MACT determination. In addition, 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
X'
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-
affected 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
40
-------
Final
May 1994
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
x-
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 may be appropriate when a single
41
-------
Final
May 1994
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
X*
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
42
-------
Final
Hay 1994
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
x*
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
43
-------
Final
May 1994
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
•v*
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 and the identification of control
technology options will be integrated processes. 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.
44
-------
Final
May 1994
3.4 Similar Emission Units
There are at least two occassions in which a permitting
agency should evaluate control technologies used by emission
units in other source categories: (1) When a negative MACT floor
finding is made during Tier I of the MACT analysis; and, (2) When
an applicant is constructing or reconstructing an emission unit.
Whether control technologies from other sources categories should
be considered in the MACT analysis depends on whether the
x»
emission unit is "similar". Two questions should be answered to
determine if an emission unit is similar: 1) Do the two emission
units have similar emission types, and 2) Can the emission units
be controlled with the same type of control technology. If the
two emission units do have similar emission types and are
controllable with the same control technologies, then the two
emission units are considered similar for the purposes of a case-
by-case MACT determination under Section 112(j).
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:
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
45
-------
Final
May 1994
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, breathing and working 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
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
46
-------
Final
May 1994
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 should 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 instance, 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
technology.
For example, suppose Section 112(j) applies to the captan
production source category (a source listed on the source
category list in Appendix D,) and a major source within this
category proposes to add additional product accumulation vessels
(tanks) and additional pipes, pumps, flanges and valves to direct
47
-------
Final
May 1994
the product to the tanks. The permitting agency determines that
the pipes, etc. are part of an existing source, but each new tank
qualifies as a new source. During Tier I of the MACT analysis,
it is determined that there are no regulations controlling HAP
emissions from pumps, etc within the source category. There is
also not enough emission information available on other emission
units within the source category to calculate a MACT floor.
During Tier II of the analysis, it is discovered that the
X*
Synthetic Organic Chemical Manufacturing Industry (SOCMI) source
category is currently subject to regulations 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. The
regulations for SOCMI equipment leaks should be considered for
the control of the MACT-affected emission unit during Tier II of
the analysis. When determining the existing source level of
control, 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.
Also during Tier I of the analysis, it is determined that
the best controlled tank within this source category does not
have state-of-the-art controls. Yet, tanks from outside the
source category storing similar organic liquids use state-of-the-
48
-------
Final
May 1994
art controls vented to an emission control device. Such tanks
are clearly "similar". The controls used on these tanks would be
considered to establish the best controlled similar source.
It is not always appropriate to consider all transferrable
technologies when determining the best controlled similar source.
It would be inappropriate to consider a transfer technology when
the emission units have different emission types. For example,
within source category X, spray booths tend to be uncontrolled
X-
due to gas streams with low concentrations and relatively high
airflows. Source category Y uses incineration to control
emissions from spray boothes with high concentrations and low
airflow volumes. The emissions from these sources are clearly
not similar, and controls for category Y would not be used to
determine the best controlled similar source for category X.
However, if it is technologically feasible to apply the controls,
these same controls could be considered to establish a new source
level of control beyond the best controlled similar source, if
consideration is given to cost, non-air guality health and
environmental impacts, and energy requirements.
49
-------
Final
May 1994
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-affected 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.
50
-------
-------
Final
May 1994
Chapter 4.0
The MACT Floor Finding
During Tier I of the MACT analysis, 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 an 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
X*
determined due to the nature of the pollutant or process; or,
(3) there is not enough emissions information to compute a MACT
floor.
The Act specifically directs EPA to consider the "average
emission limitation" to establish the MACT floor for existing
sources (emission units). 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
arithmetic mean, median or mode.
Using the calculation procedures discussed in Section 4.1,
this chapter explains three acceptable methods for determining a
MACT floor. If the emissions information is available, all three
methods should be considered before the permitting agency
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
51
-------
Final
May 1994
reduction ratios.
The first .method compares air pollution regulations in
different States. 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
X-
on the format of available information, a hybrid of the three
approaches may be necessary. Later in this chapter each of these
methods is discussed in greater detail.
52
-------
Final
May 1994
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
in practice 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:
53
-------
Final
May 1994
Example 1
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
x»
# 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
54
-------
Final
May 1994
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
N»
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
55
-------
Final
May 1994
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
x*
average emission limitation for the best performing 12% of
existing sources, the MACT floor will likely 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 sources 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
56
-------
Final
May 1994
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
N-
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, there are two modes, 99% and 89% emission
reductions. In Example 2, the mode would be equal to 0% emission
reductions; and the mode in Example 3 would be 30. When there is
more than one mode in the data set, the MACT floor should be
based on the least degree of emission control. However,
existence of more than one mode may be an indicator that the MACT
floor should be established at a level of control more stringent
than the MACT floor.
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
57
-------
Final
May 1994
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 is used more frequently by
one of the best performing 12% of existing sources; For example:
Example 4
x»
There are 44 tanks in the source category. Five sources are
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 new sources, all references to using emissions
information from within the source category should be ignored. A
determination of the best controlled similar source should not be
limited to within the source category. Readers are referred to
58
-------
Final
May 1994
Section 3.4 of this chapter for a definition of similar emission
unit.
59
-------
Final
May 1994
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 3. 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
x«>
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 an 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.
60
-------
Final
May 1994
Figure 3
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
61
-------
Final
May 1994
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 constructing or reconstructing major sources, the MACT
floor equals the most stringent State or local regulation
applying to a similar emission unit. For a modified major
source, the MACT floor is either 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 4 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
62
-------
Final
May 1994
Figure 4
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.
63
-------
Final
May 1994
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.)
x»
In this case, the MACT floor would be equal to either State A or
State B's regulations.
64
-------
Final
May 1994
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 that use add-on control
devices or other methods whose HAP control efficiencies have been
clearly demonstrated. 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 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. For
constructing and reconstructing emission units, the reduction
efficiency should be computed for all similar emission units.
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.
Step (B) Calculate the MACT floor
For new and reconstructing emission units, the MACT floor
equals the level of emission reductions that can be obtained by
65
-------
Final
May 1994
the control technology with the highest emission control rating.
For existing emission units, the MACT floor equals the arithmetic
mean of the best five or the best performing 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.
66
-------
Final
May 1994
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 5.
Step (A) Compute an uncontrolled emission level (UCEL) for each
emission unit
The UCEL for an emission unit is the maximum amount of HAP
that could be emitted from the emission unit using current design
specifications at full capacity utilization in the absence of
controls. For existing emission units, this calculation could be
done for each emission unit in the source category, and for new
and reconstructed emission units for each similar source.
However, in some circumstances, there may not be enough
information to compute a specific UCEL for each emission unit.
In such cases, it would be appropriate to develop one UCEL that
would be representative of all emission units in the source
category. Readers should review Chapter 5 for further
explanation on calculating the UCEL.
67
-------
-------
Final
May 1994
Figure 5
Using 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 Redaction Ratio (ERR) for each emission
unit.
ERR = UCEL - CEL
UCEL
Step D Determine the MACT Floor.
68
-------
-------
Final
May 1994
Step (B) Compute a controlled emission level (CEL) for each
emission unit
The CEL is the maximum amount of HAP that could be emitted
from the emission unit under the major source's current design
specification and at at full capacity utilization taking into
consideration the application of federally enforceable controls.
Ideally, A CEL should be computed for all emission units, even
when a single UCEL is used. However, if only general information
is known about the types of control technologies that are being
used in practice, a CEL could be estimated for each control
scenario. Then a CEL for each emission unit would be assigned
based on the types of controls that major sources uses. Readers
should review Chapter 5 for more information on CEL.
Step (C) Compute the emission reduction ratio (ERR) for each
emission unit:
The ERR for each emission unit can be computed using the
following formula:
ERR = UCEL - CEL
UCEL
Step (D) Determine the MACT floor.
For new and reconstructing emission units the MACT floor
would be equivalent to the highest ERR. For existing sources,
69
-------
Final
May 1994
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.
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.
70
-------
Final
May 1994
4.5 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.
71
-------
-------
Final
May 1994
Chapter 5
The MACT Emission Limitation
As previous chapters discuss, the MACT emission limitation
(MEL) is based on the degree of emission reductions that can be
obtained when MACT is applied and properly operated. Determining
the expected efficiency of an add-on control may required some
engineering judgement. In some instances, the add-on control may
achieve different levels of reduction efficiency even when it is
applied to the same type of emission unit. Lower efficiency
ratings may be due to different operational parameters or poor
maintenance practices. Other variations may be unexplainable.
The MEL should be based on the degree of efficiency that the
control technology is likely to obtain for all emission units
under good operational and maintenance practices.
Chapter 4 of this manual describes three possible
methodologies for calculating a MACT floor. It is likely that
the regulatory format of the MACT emission limitation will be
similar to the format of the MACT floor. For instance, if the
MACT floor is computed to be a limit of 0.30 Ibs/ton of feed, the
regulatory format of the MACT emission limitation is also likely
to be expressed as Ibs/ton of feed. The following sections
provide guidance on calculating the MACT emission limitation for
a source category. It also discusses how a permitting agency can
determine what amount of control an individual major source needs
72
-------
Final
May 1994
to achieve the required reductions.
5.1 Using control efficiencies to establish the MACT emission
limitation
When control efficiencies are used to establish a MACT
floor, the MACT emission limitation (MEL) could be expressed as
this efficiency. In other words all sources could be required to
N-
reduce by some percent (i.e. 90% reduction). Additional terms
and conditions would be necessary to make this federally
enforceable, but such an emission limitation may be appropriate
when the manner in which the emission unit is operated is
relatively homogenous within the source category. For other
source category it may be appropriate to convert this efficiency
rating into another format. This can be accomplished by
multiplying the efficiency of MACT by the uncontrolled emission
level (UCEL) of the emission unit as follows:
MEL = UCEL * MACT efficiency
The UCEL for an emission unit is the maximum amount of HAP
that could be emitted from the emission unit using current design
specifications at full capacity utilization in the absense of
controls. It could be computed using a variety of different
formats, i.e. tons/yr, Ibs/hr, tons/product, etc.. Acceptable
73
-------
Final
May 1994
methods for computing the UCEL are:
(a) Engineering calculation using material balance or
emission factors;
(b) Actual emission data from 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;
(g) Federal or State enforceable permit limits; or,
(h) For equipment leaks use, "Protocols for Equipment Leak
Emission Estimates," EPA-453/R-93-026.
The UCEL for the emission unit should be representative of
the typical amount of emissions that would occur from an emission
unit in the source category in the absence of controls. This
will likely require some engineering judgement on the part of the
permitting agency. Typical throughputs, flow rates,
concentrations, etc. should be used to estimate a UGEL that can
be applied to the source category.
Permitting agencies are reminded that the definition of a
control technology includes the use of pollution prevention and
source reduction strategies. The permitting agency should take
74
-------
Final
Hay 1994
into consideration the use of such control measures when
computing the UCEL for an emission unit. For example, suppose
that some major sources in the source category use a high VOC
solvent as a process input to the emission unit. Other sources
use a lower VOC solvent as a process input to the same type of
emission unit. No distinction in the type of process inputs have
been made in designating the emission unit. MACT for this
emission unit is identified as control technology X. This
control technology has been determined to have a control
efficiency rating of 90%. Using the current design
specifications for each emission unit in the category would
require all sources to reduce emissions by 90%, but would not
account for the different baseline emissions from different
emission units in the source category. By calculating the UCEL
for all emission units in the category based on the high VOC
process input, emission units with inherently lower potentials to
emit.can take credit for the emission reduction in the controlled
emissions calculation and the calculation of additional required
control.
75
-------
Final
May 1994
5.2 Using an emissions reduction ratio (ERR) to compute the MEL
When an emission reduction ratio (ERR) is used to determine
the MACT floor, the MACT emission limitation can be computed by
multiplying the uncontrolled emission level (UCEL) of the
emission unit by the emission reduction ratio (ERR) of MACT using
the following formula:
MEL = UCEL * (1 -
5.3 Additional control requirements
As previously explained in Section 3.2, a major source is
not required to install MACT in order to comply with the MACT
emission limitation (MEL) if a demonstration can be made that an
alternate control strategy can achieve the required emission
reductions. For majors sources that are already using some
control strategy, the additional required control (ARC) for that
major source can be computed by first subtracting the MACT
emission limitation from the controlled emission level (CEL) of
the emission unit as follows:
D(M-O = MEL ~ CEL
where MEL = MACT emission limitation
and CEL = Controlled emission level
76
-------
Final
May 1994
The CEL is the maximum amount of HAP that could be emitted
from the emission unit under the major source's current design
specification and at full capacity utilization taking into
consideration the application of federally enforceable controls.
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;
(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 Equipment Leak
Emission Estimates," EPA-453/R-93-026.
If MEL is based on a mass rate, production rate or
concentration rate and D^^ is equal to zero or is a positive
number, no additional control is required. The emission unit is
currently meeting the criteria for MACT. If MEL is based on a
77
-------
Final
May 1994
% removal and D^^ is equal to zero or is a negative value then
no additional control is required. Otherwise the major source
must reduce hazardous emission by the absolute value of D^^.
That is:
ARC = 1 D(M-C) 1
In some cases, it may only be necessary for the source to
establish federal enforceability of existing State requirements
x*
to meet the MEL.
78
-------
-------
Final
May 1994
Chapter 6
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
79
-------
Final
May 1994
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
X"
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
80
-------
Final
May 1994
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.
6.1 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
81
-------
Final
May 1994
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
82
-------
Final
May 1994
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 ' o~f the
company's capital structure.
83
-------
Final
Hay 1994
6.2 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
84
-------
Final
May 1994
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.
85
-------
Final
Hay 1994
6.3 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
x»
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
86
-------
Final
May 1994
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.
87
-------
-------
Final
Hay 1994
Chapter 7.0
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. Most data collection
x»
programs are designed to be compatible with the Aerometric
Information Retrieval System (AIRS)/AIRS Facility Subsystem
(AFS).
The purpose of this chapter is to present various sources of
toxics information which are available in a database format. EPA
believes the requirements of 112(j) can be less burdensome to
both industry and States by employing a database system to
document similar-category sources and provide a bibliography of
information to make a sound MACT floor determination.
AEROMETRIC INFORMATION RETRIEVAL SYSTEM (AIRS) TOXICS PROGRAM
The Aerometric Information Retrieval System (AIRS) is
designed to accommodate the expansion of emissions data. The
Aerometric Information Retrieval System (AIRS) / AIRS Facility
Subsystem (AFS) is a National Data System currently residing on
the National Computer Center (NCC). The stationary source
component of this system and replaced the old National Emission
88
-------
Final
May 1994
Data System (NEDS) as the data repository for point source data
(e.g., electric utilities, industrial plants and commercial
enterprises). The AIRS/AFS system is expected to eventually
provide the capabilities needed to house information from the
Title V operating permits program.
Many States input their data directly into the Aerometric
Information Retrieval System (AIRS) and perform calculations and
retrievals. When a converter (an interface between AIRS and the
x»
State system) is used, the data can be input directly to the
State system and to the appropriate fields in AIRS in a single
step. Data can also be retrieved from AIRS directly, or into the
State format using a converter.
Since many data sources are fed into AIRS/AFS, the system
becomes a repository of a vast amount of data. Much of this data
may 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, such as hazardous air pollutant data, is
not generally found in the State systems because it is not needed
for their current reporting requirements. However, some of this
information 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
and data elements from their participating industries.
89
-------
Final
May 1994
INFORMATION COLLECTION REQUESTS (ICR) DATA
For the national MACT standards program, the EPA is
currently involved in data collection activities for many of the
source categories on the list. These data collection activities
are designed to help answer, for a given category, a number of
important questions:
— What are the sources of emissions for the category?
— Which HAPs are emitted and atv.what rates?
— What alternatives are available to reduce those
emissions?
— What costs would be imposed for the control
alternatives, and what economic impacts would the
alternatives have on the business climate for the
industry?
Which alternatives meet or exceed the "MACT floor" (for
new sources, the "best controlled similar source;" for
existing source, the level achievable by the "average
of the best performing 12 percent" of sources in the
category)
— Given the alternatives available, which alternative
represents the "maximum degree of reduction
achievable," taking into account costs, benefits, and
the constraints imposed by the "MACT floor?"
THE PROPOSED MACT DATABASE
The same general types of questions that EPA currently looks
at for MACT standards, States or industry owner/operators would
be called upon to address in making case-by-case MACT
determinations in accordance with Sections 112(g) and 112(j). It
is probable that many such case-by-case MACT determinations will
90
-------
Final
May 1994
be needed (particularly for Section 112(g) purposes) before
extensive nationwide data collection efforts will be completed by
the EPA. For such situations, there has been significant concern
on the part of industry that the effort needed for a MACT
determination could lead to substantial delays. In addition,
States have expressed concerns regarding the manpower
requirements for MACT determinations, and regarding the
availability of data for making "MACT floor" determinations. The
x-
project to establish a data base for MACT determinations (called
the MACT database) was initiated to address those concerns. The
project may also serve to assist EPA in its own data collection
efforts for the 7 and 10-year MACT categories for which national
data collection efforts have not yet begun.
Several documents have been released in draft form to
explain and give guidance to potential users of the MACT
Database. For further information on this subject, a scoping
document on the MACT Database is available on the Office of Air
Quality Planning and Standards (OAQPS) Technology Transfer
Network (TTN) Bulletin Board. This information can be found on
TTN under the menu (J) Airs Data and submenu (M) MACT data. For
more information on this project, contact Susan Fairchild-Zapata
at 919-541-5167.
BACT/LAER CLEARINGHOUSE INFORMATION SYSTEM (BLIS)
The BACT/LAER Clearinghouse, or the BACT/LAER Information
91
-------
Final
May 1994
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.
Participation in BLIS is on a voluntary basis. If
participation in BLIS increases, it may be able to provide
N»
sufficient information to determine the 12% floor with increasing
accuracy. For more information on BLIS, contact Bob Blaszczak at
919-541-5432.
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 with
reports to Congress are required under the Great Waters program.
Updates of the emission inventory are anticipated to support both
the periodic assessments and refine dispersion models as they
become available. For additional information on the Great Waters
Program, contact Amy Vasu at 919-541-0107.
FIRE: RATED AIR TOXIC EMISSION FACTORS
The requirements of the CAAA dictate immediate sampling and
92
-------
Final
May 1994
analysis to obtain data for determination of emission factors.
Emission factors are used in lieu of emission estimates based
upon source testing, and estimate the emissions of a particular
HAP per unit process rate (i.e., pounds of nickel emitted for
each ton of nickel ore processed). These emission factors can be
based on controlled and uncontrolled processes, and can therefore
be used to help determine which control measures are best suited
to a particular process. 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 toxic emission factors available through FIRE are 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 compounds, of which about 170 are on the
list of 189 HAPs in Section 112(b), representing many (but not
all) processes in Section 112 source categories.
About 40 of the HAPs in FIRE 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. For
more information on FIRE, contact Anne Pope at 919-541-5373.
93
-------
Final
May 1994
TITLE V OPERATING PERMIT SYSTEM
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 information from Title V
permits. This database is generally referred to as the permit
system. Phase I of the Title V Operating permit system has been
designed in AIRS/AFS. It is not expected to provide much of the
x*
information needed for determining the MACT floor for case-by-
case MACT determinations or for MACT standards.
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
on an annual basis by voluntary submittal from participating
agencies.
Since its introduction in 1984, NATICH has undergone
94
-------
Final
May 1994
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. For more
information on NATICH, contact Vasu Kilaru at 919-541-5332.
>-
TOXIC RELEASE INVENTORY SYSTEM (TRIS)
This is a source of data that is used to identify HAP
emitters by records of accidental releases. 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. 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). For
information on TRIS contact Vasu Kilaru at 919-541-5332.
95
-------
Final
May 1994
STATE AIR OFFICE DATABASES
Emissions Standards Division (BSD) 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
x.
well as State requirements for toxics programs. 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 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.
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
96
-------
Final
May 1994
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, but may provide
some useful information on control alternatives.
97
-------
Final
May 1994
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.
x«-
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).
Environmental Protection Agency (EPA), January 1990. OAQPS
Control Cost Manual. EPA, 450/3-90-006.
Environmental Protection Agency (EPA). June 1991. Control
Technologies for Hazardous Air Pollutants.
EPA, EPA/625/6-91/014.
98
-------
-------
Final
May 1994
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.
-------
-------
Final
May 1994
Example 1
Determining the
MACT-Affected Emission Unit
The owner or operator of a major source in the metal furniture -
surface coating 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:
N"
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
A - 2
-------
Final
May 1994
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.
x-
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.
After cleaning, the parts are conveyed to a dry-off oven and then
A - 3
-------
Final
May 1994
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
X-
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 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
A - 4
-------
Final
May 1994
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
parts surface coating source category.
A -
-------
Final
May 1994
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
controlled while others could be over-controlled. This option
A - 6
-------
Final
May 1994
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.
A -
-------
Final
May 1994
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.
A - 8
-------
Final
May 1994
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 rationale for this conglomeration
would be necessary.
A -
-------
Final
May 1994
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
permitting agency will need to conduct a MACT analysis to
determine the MACT emission limitation based on the emission
reduction that can be achieved by MACT. The permitting agency
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. The permitting agency decides 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.
The permitting agency is able to find the following
information:
A - 10
-------
Final
Hay 1994
step 2} Make a MACT floor Finding
Techno1oqy
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 scrubberJ 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%
A - 11
-------
Final
May 1994
The permitting agency decides 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 3 Identify 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 technology 1 is to be considered further, 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,
A - 12
-------
Final
May 1994
technology number 1 would be considered inferior and should be
eliminated as a potential candidate.
The permitting agency should identify MACT based on the
control technology that achieves a maximum degree of emission
reduction with consideration to the costs, non air quality health
and environmental impacts and energy requirements associated with
use of each conntrol technology. After identifying MACT, the
permitting agency would proceed to Tier III of the analysis.
A - 13
-------
Final
May 1994
Example 3
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
X*
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 l) 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
A - 14
-------
Final
May 1994
the feed line and waste lines have equipment leak emissions,
these emission points should be combined to form a MACT-affected
emission unit. The permitting agency 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
x»
application equipment, paint supply system, a storage container,
and a drying oven. The permitting agency decides to combine
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.
A - 15
-------
Final
May 1994
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
A - 16
-------
-------
Final
May 1994
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
-------
Final
Hay 1994
Source
23
24
25
26
27
28
29
30
Technology
/
1
6
4
4
4
4
6
1
Uncontrolled
emissions
(tona/yr)
95
96
64
98
168
196
186
255
Controlled
emissions
(tona/yr)
10
16
25
31
45
63
186
26
Emission
Reduction
Ratio
.89
.83
.61
.68
.73
.68
0
.90
A - 18
-------
Final
May 1994
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
"V-
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.
Step D Determine a MACT emission limitation (MEL)
The permitting agency calculates an uncontrolled emission
rate for the MACT-affected emission unit based on the normal
operation of the emission unit. Emission reductions obtained
through a pollution prevention strategy would not be included in
the UCEL calculation. The permitting agency calculates the UCEL
for this emission unit to be 125 tons/yr total HAPs. Based on
this UCEL, The MEL for this emission unit would be
MEL = 125 tons/yr * (1 - 0.88)
= 15 tons/yr
The permitting agency would advise the permit applicant of
A - 19
-------
Final
May 1994
the MEL and allow the applicant to determine how this level of
emission reductions will be achieved.
Step 4 Select a control technology to meet the MACT Emission
Limitation.
In this example, the nature of the product requires a
specific type of coating and because of this the applicant is
unable to use any of the reviewed technologies to meet the MEL.
The owner and operator will analyze other control technologies
that are applied to control similar emission points. 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
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
A - 20
-------
Final
May 1994
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 control technology 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
fuel requirement, a significant increase in C02 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.
A - 21
-------
Final
May 1994
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 is 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.
A - 22
-------
Final
May 1994
Example 4
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
A - 23
-------
Final
May 1994
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. The permitting agency 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 permitting agency will also group the distillation
column, distillate receiver and condenser into one MACT-affected
x»
emission unit. The feed lines, pumps, and transfer lines would
have equipment leak emission losses and would be another affected
emission unit. The permitting agency decides 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 permitting agency reviews existing data bases
and determines 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"
measure, so the owner or operator will move to Tier II of the
A - 24
-------
Final
May 1994
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.
Step 3) Conduct a Non-air Quality Health, Environmental,
Economic and Energy Impacts Analysis
The following series of tables illustrate a non-air quality
health, environmental, cost and energy impacts analysis for each
control option.
Table 1 presents information describing the various control
technologies that are technically feasible. Secondary air
impacts as well as energy impacts and other resource demands.
A - 25
-------
Final
May 1994
Table 1
Control Option
Secondary Air
Impacts
Resource Demands
1 fixed roof
none
none
2 fixed roof +
internal roof
none
none
3 pressure tank
none
none
4 cover and
vented to
carbon canister
emission if
carbon regenerated
disposal of
container, solvents
for regeneration
5 cover and vent
to combustion
devise
increased CO, NOx,
SOx, and
particulate
emissions
fuel source,
disposal of ash
6 cover and vent to
carbon absorber
emissions when
carbon regenerated
disposal of spent
carbon, solvents
for regeneration
A - 26
-------
Final
May 1994
Table 2 presents the control options along with their costs
and emission reductions. The average cost effectiveness of each
control option is also presented. The average cost effectiveness
is the ratio of the total annual cost to the total amount of HAP
removed. Note that the control options are presented in terms of
increasing annual cost (i.e., control option 1 has the smallest
annual cost, control option 2 has the second smallest annual
cost, etc.)
>»
Using Table 2, several control options can be eliminated
from further consideration. Control option 3 should be
eliminated because control option 2 achieves the same amount of
HAP reductions but at a lower cost. Control option 2 should be
eliminated because control option 4 achieves a greater degree of
emission reduction for lower cost. The elimination of control
options 2 and 3 reduces the number of technically feasible and
economically efficient options to four control technologies.
Table 3 presents the incremental cost effectiveness of the
remaining options. The incremental cost effectiveness of control
option 1 is the same as its average cost effectiveness since
control option 1 is the first incremental option from the
baseline. The incremental cost effectiveness of control option 4
is the ratio of the difference in cost between options 1 and 4 to
the difference in HAP emission reductions between the two ratios.
A - 27
-------
Final
May 1994
Table 2
CONTROL
OPTION
1
2
3
4
5
6
CONTROL
EFFICIENCY
93
96
96
98
99
100
ANNUAL COST
($)
85,000
113,000
232,000
110,000
136,000
189,000
EMISSION
REDUCTION
(Mg/Yr)
72
88
88
92
103
117
AVERAGE
COST-
EFFECTIVENESS
($/Mg)
1,161
1,264
2,636
1,156
1,320
1,615
Table 3
CONTROL
OPTION
1
4
5
6
ANNUAL COST
($)
85,000
110,000
136,000
189,000
EMISSION
REDUCTION
(Mg/Yr)
72
92
103
117
AVERAGE
COST-
EFFECTIVENESS
($/Mg)
1,161
1,156
1,320
1,615
INCREMENTAL
COST
EFFECTIVE-
NESS ($/Mg)
1,250
2,364
3,766
A - 28
-------
Final
May 1994
Step 4) Identify MACT
Examination of the cost effectiveness of the various control
options can lead to the elimination of some control options.
Control option 6 is eliminated because the incremental cost is
deemed too high. The incremental cost of control option 5 is
deemed acceptable but upon closer examination, the secondary air
and energy impacts make this option undesirable. The incremental
cost of both options 1 and 4 are deemed acceptable; however,
•v-
control option 1 is eliminated because other considerations
(secondary air impacts, etc) do not preclude the selection of
control option 4 which achieves a greater degree of emission
reductions.
A - 29
-------
-------
Final
May 1994
Appendix B
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 Administrator of 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 that is part of an
emission unit 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 in Chapter 40 of the CFR established
pursuant to Title V of the Act (42 U.S.C. 7661).
Controlled emissions - the maximum amount of HAP that could be
emitted from the emission unit under the major source's current
design specification and at full capacity utilization taking into
consideration the applciation of federally enforceable controls.
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
B - 1
-------
Final
May 1994
certification) as provided in subsection (h), or
(5) are a combination of above.
Commenced - with respect to construction or reconstruction of a
stationary source, that an owner or operator has undertaken a
continuous program of construction or reconstruction 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 in compliance with the MACT emission limitation.
Construction - on-site fabrication, erection, or installation of
an emission unit.
Continuous emission monitoring system (GEMS) - the total
equipment that may be required to meet the data acquisition and
availability requirements 40 CFR Part 63, used to sample,
condition (if applicable), analyze, and provide a record of
emissions.
Continuous monitoring system (CMS) - a comprehensive term that
may include, but is not limited to, continuous emission
monitoring systems, continuous parameter monitorin gsystems, or
other manual or automatic monitoring that is used for
demonstrating compliance with an applicable regulation on a
continusous basis as defined in a permit or regulation.
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 related. Equipment is functionally related if the
B - 2
-------
Final
May 1994
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 that are
enforceable by the Administrator and citizens under the Act or
that are enforceable under other statutes administered by the
Administrator. Examples of federally enforceable limitations and
conditions include, but are not limited to:
(1) Emission standards, alternative emission standards,
alternative emission limiations, and equivalent emission
limitations established pursuant to Section 112 of the Act as
amended in 1990;
(2) New source performance standards established pursuant to
Section 111 of the Act, and emission standards established
pursuant to Section 112 of the Act before it was amended in 1990;
(3) All terms and conditions in a title V permit, including
any provisiosn that limits a source's potential to emit, unless
expressly designated as not federally enforceable;
(4) Limitations and conditions that are part of an approved
State Implementation Plan (SIP) or a Federal Implementation Plan
(FIP);
(5) Limitations and conditions that are part of a Federal
construction permit issued under 40 CFR 52.21 or any construction
permit issued under regulations approved the the EPA in
accordance with 40 CFR Part 51;
(6) Limitations and conditions that are part of an operation
permit issued pursuant to a program approved by the EPA into a
SIP as meeting the EPA's minimum criteria for Federal
enforceability, including adequeate notice and opportunity for
EPA and public comment prior to issuance of the final permit and
practicable enforceability;
(7) Limitations and conditions in a State rule or program
that has been approved by the EPA under subpart E of Part 63 for
the purposes of iimplementing and enforcing Section 112; and
(8) Individual consent agreements that the EPA has legal
authority to create.
B -
-------
Final
May 1994
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.
Maxim111" achievable control technology (MACT) — a control
technology 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 emissiqn 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 or
the permitting agency 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
B - 4
-------
Final
May 1994
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 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.
Major 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.
Permit program - a comprehensive State operating permit system
B - 5
-------
Final
May 1994
established pursuant to~ Title V of the Act and regulations
codified in Part 70 of this chapter and applicable State
regulations, or a comprehensive Federal operating permit system
established pursuant to Title V of the Act and regulations
codified Chapter 40 of the CFR.
Permit revision - any permit modification or administrative
permit amendment to a Title V permit.
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 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 emission
unit 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 established pursuant to Section
112 of the Act that applies to the stationary source, group of
stationary soruces, or the portion of stationary source regulated
by such standrd or limitation.
A relevant standard may include or consist of a design,
B - 6
-------
Final
May 1994
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) establishes for new or existing
source to which such stadard 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.
x-
Source - an emission unit, or as otherwise specified in an
applicable 40 CFR Part 63 emission standard.
Start-up - setting in operation an affected emission unit for any
purpose.
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.
Title V permit - any permit issued, renewed, or revised pursuant
to Federal or State regulations established to implement Title V
of the Act. A title V permit issued by a State permitting
authority is called a part 70 permit.
Uncontrolled emissions - the maximum amount of HAP that could be
emitted from the emission unit using current design
specifications at full capacity utilization in the absense of
controls.
B -
-------
-------
Final
May 1994
Appendix C
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'*
Stationary Turbines'*
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 S'teel 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
C-l
-------
Final
May 1994
Asphalt Concrete Manufacturing
Asphalt Processing
Asphalt Roofing Manufacturing
Chromium Refractories Production
Clay Products Manufacturing
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)
C-2
-------
Final
May 1994
Waste Treatment and Disposal
Category Name
Hazardous Waste Incineration
Municipal Landfills
Sewage Sludge Incineration
Site Remediation
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
C-3
-------
Final
Hay 1994
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
Ethylene-Propylene Elastomers Production
Flexible Polyurethane Foam Production
Hypalon (tm) Production
Maleic Anhydride Copolymers Production
Methylcellulose Production
Methylcellulose Production
Methyl Methacrylate-Aerylonitrile-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
C-4
-------
Final
May 1994
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
Production of Organic Chemicals
Category Name
Synthetic Organic Chemical Manufacturing
x»
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
P-hthalate Plasticizers Production
Plywood/Particle Board Manufacturing
C-5
-------
Final
May 1994
Polyether Polyols Production
Pulp and Paper Production
Rocket Engine Test Firing
Rubber Chemicals Manufacturing
Semiconductor Manufacturing
Symmetrical Tetrachloropyridine Production
Tire Production
Wood Treatment
C-6
------- |