REPORT
MANUAL FOR CATEGORIZING PROPOSED
PERMIT CHANGES UNDER THE TITLE V OPERATING
PERMIT PROGRAM
Work Assignment No. 0-2
EPA Contract No. 68-D3-0031
MRI Project No. 4200-02
Prepared for:
Permits Programs Branch
Air Quality Management Division (MD-15)
U. S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
Prepared by:
Midwest Research Institute
401 Harrison Oaks Boulevard
Cary, North Carolina 27513
April 14, 1994
401 Harrison Oaks Boulevard, Gary, NC 27513-2412 • (919) 677-0249
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REPORT
MANUAL FOR CATEGORIZING PROPOSED PERMIT
CHANGES UNDER THE TITLE V
OPERATING PERMIT PROGRAM
Work Assignment No. 0-2
EPA Contract No. 68-D3-0031
MRI Project No. 4200-02
Prepared for:
Permits Programs Branch
Air Quality Management Division (MD-15)
U. S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
Prepared by:
Midwest Research Institute
401 Harrison Oaks Boulevard
Cary, North Carolina 27513
April 14, 1994
MIDWEST RESEARCH INSTITUTE 401 Harrison Oaks Boulevard, Gary, NC.27513-2412 • (919)677-0249
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DISCLAIMER
Although the information in this document has been funded wholly or hi part by the
United States Environmental Protection Agency under Contract No. 68-D3-0031, Work
Assignment No. 0-2 to Midwest Research Institute, it does not necessarily reflect the views
of the Agency and no official endorsement should be inferred.
This report is interim guidance only. The operating permit program regulations under
40 CFR part 70 are currently under litigation, which will result in a required revision to
part 70. Subsequent guidance will be issued that will reflect any changes to part 70.
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PREFACE
This report was prepared for Mr. Gary Rust of the Air Quality Management Division,
U. S. Environmental Protection Agency (EPA), Research Triangle Park, North Carolina,
under EPA Contract No. 68-D3-0031, Work Assignment No. 0-2. This report is a manual
to help State and local permit writers categorize proposed permit changes from industry
under Title V of the Clean Air Act.
Approved for:
MIDWEST RESEARCH INSTITUTE
Richard V. Grume
Program Manager
Environmental Engineering Department
Jeff Shular
Director, Environmental Engineering
Department
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IV
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TABLE OF CONTENTS
1.0 INTRODUCTION 1-1
1.1 PURPOSE OF MANUAL 1-1
1.2 ORGANIZATION OF MANUAL 1-2
2.0 UNDERSTANDING OPERATING PERMIT CHANGES
AND RELATED CONCEPTS 2-1
2.1 OPERATIONAL FLEXIBILITY 2-1
2.1.1 Section 502(b)(10) Changes 2-2
2.1.2 Emissions Trading Based on the SIP 2-3
2.1.3 Emissions Trading Under Emissions Caps 2-4
2.2 OFF-PERMIT CHANGES 2-5
2.3 PERMIT REVISIONS 2-6
2.3.1 Administrative Amendments 2-6
2.3.2 Minor Permit Modifications 2-7
2.3.3 Significant Permit Modifications 2-10
2.4 ALTERNATIVE OPERATING SCENARIOS/FLEXIBLE PERMIT
CONSTRUCTION 2-10
2.5 PERMIT SHIELD 2-12
2.6 INSIGNIFICANT ACTIVITIES 2-12
3.0 STEP-WISE METHODOLOGY FOR IDENTIFYING
AND CATEGORIZING OPERATING CHANGES 3-1
3.1 REVIEW CHANGE AGAINST EXISTING PERMIT 3-4
3.2 TERMS AND CONDITIONS THAT MAY PROHIBIT A PROPOSED
CHANGE 3-4
3.3 CHANGES THAT CAN BE MADE WITHOUT A PERMIT REVISION 3-5
3.3.1 Alternative Operating Scenarios 3-5
3.3.2 Off-Permit Changes 3-5
3.3.3 Operational Flexibility 3-7
3.5 MINOR PERMIT MODIFICATIONS 3-10
3.6 SIGNIFICANT PERMIT MODIFICATIONS 3-12
3.7 CHANGES THAT CANNOT BE MADE UNDER PART 70 3-12
4.0 APPLICATION OF STEP-WISE METHODOLOGY TO CASE STUDIES . . 4-1
4.1 VEHICLE MANUFACTURING CASE STUDY 4-1
4.2 PHARMACEUTICAL MANUFACTURING CASE STUDY 4-6
4.3 PULP AND PAPER CASE STUDY 4-12
4.4 SYNTHETIC ORGANIC CHEMICAL MANUFACTURING
CASE STUDY 4-17
APPENDIX A - TITLE I MODIFICATIONS
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VI
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LIST OF FIGURES
Page
3-1 (a) Step-Wise Methodology for Identifying and Categorizing
Proposed Changed (Permit Revisions Not Required) 3-2
3-l(b) Step-Wise Methodology for Identifying and Categorizing
Proposed Changed (Permit Revisions Required) 3-3
3-2 Changes Not Requiring a Permit Revision 3-6
3-3 Administrative Amendments 3-8
3-4 Minor and Significant Permit Modifications 3-11
4-1 Configuration of a Hypothetical Pharmaceutical Manufacturing Facility .... 4-7
4-2 Equipment Layout for Typical Pharmaceutical Batch Process 4-8
4-3 Typical Kraft Process 4-13
LIST OF TABLES
Page
4-1 COMPARISON OF EMISSIONS DUE TO PROPOSED FUEL CHANGE . . 4-5
4-2 ACTUAL AND PERMITTED EMISSIONS FOR HYPOTHETICAL
FACILITY 4-9
4-3 ACTUAL EMISSIONS FOR ONE BATCH PROCESS UNIT 4-9
Vll
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1.0 INTRODUCTION
Title V of the Clean Air Act as amended in 1990 (the Act) established a new State-
implemented operating permit program with Federal oversight. On July 21, 1992, EPA
promulgated regulations (57 FR 32295) establishing the minimum elements of a State
program at 40 CFR part 70 (part 70). Part 70 contains several processes to allow operational
changes at a facility. Under certain circumstances, changes may be made without a permit
revision (e.g., operational flexibility, off-permit changes, and alternative operating
scenarios); under other circumstances, permit revisions (e.g., administrative amendments and
minor and significant permit modifications) are necessary to make the change. Requirements
for categorizing and processing each of these types of operational changes are detailed in
§§70.4, 70.6, and 70.7.
Where appropriate and allowable under State permit programs approved by EPA,
changes that are allowed without a permit revision benefit both the permitted source and the
permitting authority. The source is able to respond more quickly to business and operational
demands, and the permitting authority is not required to devote valuable resources to matters
not required by regulation or environmental needs. The viability and use of concepts such as
operational flexibility depends upon both the regulated community and the permitting
authority having a sound understanding of these concepts and building them into the permit
application, revision, and review process. A well-designed permit application and permit
will provide flexibility where warranted and allowed by statute and regulation.
1.1 PURPOSE OF MANUAL
This manual has been developed to help State and local agency permit staff identify
and process the different types of operational changes and permit revisions that are
authorized by part 70 and Title V. The focus of this manual is to guide the permit reviewer
through a step-wise process for categorizing operational changes into appropriate categories
of permit revisions, off-permit changes, and operational flexibility. Examples are provided
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in the text to help the reader gain a better understanding of each concept that is discussed.
In addition to these examples, four case studies are provided to give the reader an
opportunity to apply the step-wise process.
1.2 ORGANIZATION OF MANUAL
Section 2.0 of this manual provides an overview of the categories of operating
changes and other related permitting concepts under part 70. The step-wise methodology for
categorizing operating changes, including supporting flowcharts, is presented in Section 3.0.
Section 4.0 contains the four case studies. Title I modifications, an understanding of which
is important throughout the manual, are discussed in Appendix A.
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2.0 UNDERSTANDING OPERATING PERMIT CHANGES
AND RELATED CONCEPTS
Part 70 introduces several categories of operating changes that a permitted source may
need over the life of its permit. To effectively implement the permit program, State and
local permit reviewers should be able to readily identify the differences between these
categories of operating changes. Once the category has been identified, the reviewer should
be familiar with the different procedures that must be followed to process the change. In
general, changes require the permitting authority to either acknowledge the change without
revising the permit or revise the source's permit to reflect the change. Permit reviewers
must also be aware of various requirements that may apply depending on the category of
change, such as notification procedures, review and approval requirements, and waiting
periods before changes may be implemented by the source. The remainder of this section
provides an overview of the categories of operating changes and other related permitting
concepts under part 70.
2.1 OPERATIONAL FLEXIBILITY
All State and local programs must provide for operational flexibility in the federally-
enforceable portions of operating permits. (Operational flexibility is not required for State-
only requirements.) Operational flexibility allows industry to respond quickly in some cases
to changing business conditions, but does not compromise the ability of the permitting
authority to hold the source responsible for compliance with all applicable requirements
under the Act. Under operational flexibility provisions, no permit revision is necessary.
However, none of these changes may be Title I modifications or increase emissions beyond
what is allowed in the permit. (Title I modifications are discussed in Appendix A of this
manual.) Sources are required to notify the Administrator and the permitting authority, in
writing, 7 days in advance of the change.
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Section 70.4(b)(12) identifies the following three ways to provide operational
flexibility:
1. Allow changes within a facility that contravene certain narrowly-defined permit
terms, as long as the source does not exceed the emissions allowable under the permit;
2. Allow emissions trading to meet State implementation plan (SIP) limits where
the SIP provides for such trading on 7 days notice in cases where trading is not already
provided for in the permit; and
3. Allow emissions trading to comply with a federally-enforceable emissions cap
established in the permit that is independent of or more strict than otherwise applicable
requirements.
The first and third types of operational flexibility are mandatory for State and local
programs; the second type is optional. Each of these types of operational flexibility is
discussed in further detail below.
2.1.1 Section 502(fr)(10) Changes
The first type of operational flexibility, commonly referred to as "section 502(b)(10)
changes," are changes that contravene (or make inapplicable) an express permit term.
(Section 502(b)(10) refers to the section in Title V of the Act that requires changes to be
allowed in operating permit programs that do not require permit revisions.) Such changes do
not include changes that would violate any applicable requirement (e.g., SIP requirement,
national emission standards for hazardous air pollutants requirement, etc. ~ see §70.2 for
complete list). Also, permit terms that cannot be affected are monitoring (including test
methods), recordkeeping, reporting, and compliance certification requirements. These terms
are excluded because they are critical to determining allowable emissions under the permit.
Because these kinds of terms make up most if not all of the permit's terms and conditions, it
is clear that section 502(b)(10) changes apply to an extremely limited set of terms that are
incidental to demonstrating compliance with applicable requirements. These changes can be
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viewed as supplying excessive detail and thereby limiting a source's flexibility.
Consequently, contravening these terms should not jeopardize compliance with applicable
requirements.
No permit revision is necessary to make section 502(b)(10) changes. Written
notification is required to the Administrator and the permitting authority 7 days in advance of
the change. The notification must include, at a minimum, the date of the change, a
description of the change, any change in emissions, and any permit term that is no longer
applicable as a result of the change.
An example of an acceptable section 502(b)(10) change is allowing a source to
contravene a permit term that specifies a certain brand of coating to be used, provided that
the new brand of coating meets the emission limit in the permit and appropriate notice is
given of the change.
2.1.2 Emissions Trading Based on the SIP
The second type of operational flexibility gives States the option of allowing a
permitted facility to trade increases and decreases in emissions where the applicable SIP
allows for such emissions trading. Emissions trading would be allowed in those cases where
the permit does not already provide for the trading, as long as the SIP allows trading based
on a 7-day notice. This option would be useful to sources that had not anticipated the need
to trade emissions when the permit was originally issued. Each permit for a source eligible
for this type of trading would include the applicable SIP emission limit. Upon giving the
7-day notice, the source could then meet the SIP limits using the applicable trading and
compliance provisions approved in the applicable SIP.
No permit revision is necessary to make this type of change. Written notification is
required to the Administrator and the permitting authority 7 days in advance of the change.
The notification must include, at a minimum, the date of the change, a description of the
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change, any change in emissions, the permit requirements with which the source will comply
using the emission trading provisions of the SIP, and the pollutants emitted subject to the
emissions trade. The EPA, permitting authority, and facility must attach a copy of the
notification to their copies of the original permit.
For example, many States are adopting nitrogen oxides (NOX) reasonably available
control technology (RACT) rules that allow emissions trading in their SIP's in accordance
with EPA's "State Implementation Plans; Nitrogen Oxides Supplement to the General
Preamble for the Implementation of Title I of the Clean Air Act Amendments of 1990"
(57 FR 55620, November 25, 1992). An electric utility in such a State may trade NOX
emissions in accordance with the SIP without having permit conditions that specifically
address emissions trading. However, the State permitting program must contain a provision
allowing such trading, and proper notification must be given to the Administrator and the
permitting authority. After the 7-day notice period is over, the source would then meet the
SIP limits using the SIP trading provisions rather than the compliance provisions in the
permit. Trading may be conducted at any time without further notice to the permitting
authority, but a record of the trades would have to be made.
2.1.3 Emissions Trading Under Emissions Caps
The third type of operational flexibility involves emissions trading for purposes of
complying with an emissions cap established in the permit (e.g., a voluntary emission limit)
that is independent of any applicable requirement. The source can request emissions trading
provisions in the permit application, provided the source also complies with all limits on
individual emission units and all SIP requirements. If the source requests emissions trading
and proposes replicable procedures and permit conditions that ensure the emission trades are
quantifiable and enforceable, the permitting authority must include the emissions trading
procedures in the permit.
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No permit revision is necessary to make this type of change. Written notification is
required to the Administrator and the permitting authority 7 days in advance of the change.
The notification must include, at a minimum, the date of the change, a description of the
changes in emissions that will result, and an explanation of how these increases and
decreases in emissions will comply with the permit terms and conditions.
For example, a coating facility may request a voluntary limit (cap) in their permit
application on their potential to emit volatile organic compounds (VOCs) that is lower than
anything required under the SIP or other applicable requirements. The facility may request
this cap to avoid a requirement, such as VOC RACT. After a 7-day notice period, the
facility could then conduct emissions trading between coating lines as long as the facility-
wide emissions cap is met and each line is in compliance with the SIP and other applicable
requirements. The facility would have to keep records of the actual emissions from all
coating lines involved to show that the trades are quantifiable and enforceable.
Facilities that are subject to only work practice standards and not emission limits
would not qualify for trading under this scenario. For example, a degreaser that is subject to
work practice standards -- having a cover that is easily opened and closed, keeping the cover
closed except when in use, haying safety switches, and minimizing solvent carryout - is not
eligible for trading because the emission trades would not be quantifiable or enforceable.
2.2 OFF-PFJIMTT CHANGES
Off-permit changes under §70.4(b)(14) are changes that are not specifically addressed
or prohibited by the permit and are not precluded by any applicable requirement under the
Act. Because permits summarize existing regulations that apply to the source, they cannot
possibly address every change that a source may make. Off-permit changes allow sources to
make certain types of changes without requiring a permit revision or a waiting period,
provided these changes are not Title I modifications or subject to Title IV acid rain program
requirements.
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Off-permit changes do not require permit revisions. Sources are required to notify
the Administrator and the permitting authority in writing on the day the change takes place.
Written notification must include, at a minimum, a description of the change including the
date, any change in emissions, pollutants emitted, and any applicable requirement that would
apply as a result of the change. If the change is considered an "insignificant activity" under
the approved State program, no notification is necessary. (Section 2.6 of this manual
discusses insignificant activities.)
An example of an off-permit change is to allow a source that is subject to an emission
rate limitation (e.g., mass of VOC per volume of coating) to use a new type of coating not
expressly provided for in the permit, as long as compliance with the emission rate limitation
is maintained. Another example is to allow installation of a new unit (provided it is not a
Title I modification).
2.3 PERMIT REVISIONS
Section 70.7 established three types of permit revisions: (1) administrative
amendments, (2) minor permit modifications, and (3) significant permit modifications. The
three types of permit revisions are discussed below.
2.3.1 Administrative Amendments
Administrative amendments are generally changes or corrections to permit details;
however, they may also include incorporation of requirements for a State's new source
review (NSR) program. Section 70.7(d) lists the following types of administrative
amendments:
1. Correction of typographical errors;
2. Changes in the name, address, or phone number of any person in the permit;
3. Increases in the frequency of monitoring or reporting by the permittee;
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4. Changes in ownership or operational control of the facility; and
5. Incorporation of preconstmction permit requirements into part 70 permits
(provided the State's NSR program meets procedural requirements substantially equivalent to
part 70 requirements for permit modifications and compliance requirements substantially
equivalent to those in part 70).
In addition, State programs may list other similar types of changes that have been approved
by EPA as administrative amendments.
The EPA includes incorporation of preconstmction permit requirements as an
administrative amendment provided these changes have already received sufficient EPA
review and opportunity for public comment and a hearing. Many State NSR programs need
to be "enhanced" to meet the substantive and procedural part 70 requirements.
Accomplishing these NSR program enhancements would allow the permitting authority to
consolidate NSR and part 70 permit revision procedures.
Changes that qualify as administrative amendments can be made without notice to the
public or affected States. The facility must request the amendment from the permitting
authority and may implement the change immediately upon submission of the request.
Within 60 days from receipt of such a request, the permitting authority must either approve
or deny the request. If the request is approved, the permitting authority will send a copy of
the revised permit to EPA. If the request is denied, the original permit remains fully
enforceable.
2.3.2 Minor Permit Modifications
As part of the effort to match procedural elements to the significance of a change,
EPA developed minor permit modification procedures, which are designed for smaller
changes at a facility. Changes under the minor permit modification process should not
involve complicated regulatory determinations and must meet specific criteria.
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Section 70.7(e)(2)(i) identifies several "gatekeeper" criteria, which are intended to screen a
proposed change for applicability as a minor permit modification. Specifically, a minor
permit modification can only be used for modifications to the source that:
1. Do not violate any applicable requirement;
2. Do not involve significant changes to existing monitoring, reporting, or
recordkeeping requirements in the permit;
3. Do not require or change: (1) a case-by-case determination of an emission
limitation or other standard (e.g., MACT standard or RACT, BACT, or LAER
determination), (2) a source-specific determination of ambient impacts, or (3) a visibility or
increment analysis;
4. Do not seek to establish or change a permit term or condition for which there is
no corresponding applicable requirement and that the source has assumed to avoid an
applicable requirement to which the source would otherwise be subject. Such terms and
conditions include:
~ A federally enforceable emissions cap assumed to avoid classification as a
modification under any provision of Title I of the Act (e.g., a change to a
previously established voluntary cap to escape new source review); and
~ An alternative emissions limit approved pursuant to regulations promulgated under
§112(i)(5)oftheAct;
5. Are not modifications under any provision of Title I of the Act; and
6. Are not required by the State program to be processed as a significant
modification.
As indicated above, only insignificant changes in existing monitoring, reporting, or
recordkeeping requirements can be processed as minor permit modifications. An example of
an insignificant change in monitoring would be to switch from one validated reference test
method for a pollutant and source category to another validated method where the permit
does not already provide for an alternative test method.
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Notwithstanding the above criteria, States may process economic incentives, emissions
trading, marketable permits, or other similar approaches under the minor permit modification
process, provided the underlying SIP or EPA rule explicitly provides for use of minor permit
modification procedures when implementing these types of changes. The use of emissions
trading as part of operational flexibility when no permit modification is required is discussed
in Sections 2.1.2 and 2.1.3 of this manual.
To use the minor permit modification process, a source must file a complete
application demonstrating that it qualifies for minor permit modification processing. The
application must include a description of the change, the emissions resulting from the change,
any new applicable requirements that will apply if the change occurs, a suggested draft
permit, and the necessary certification that the proposed modification meets the criteria for
minor permit modification procedures. In addition, the application must meet all the
requirements of §70.5(c) for information required. The source is allowed to make the
change immediately upon filing the application. While the application is pending, the source
would receive a qualified exemption from the requirement that it comply with the specific
existing permit terms. This exemption would be in effect provided the source operates in
compliance with the proposed terms and conditions and complies with the applicable
requirements governing the change.
Within 5 working days of receipt of a complete permit application, the permitting
authority must notify affected States of the requested permit modification and transmit the
proposed permit and other necessary documents to the Administrator. The permitting
authority must act on the permit modification within 90 days of receipt of the application or
15 days after the end of the Administrator's 45-day review period, whichever is later. This
action may include issuing the permit modification as proposed, denying the permit
application, revising the draft permit modification and transmitting the new revision to the
Administrator, or determining that the minor modification procedures are inappropriate and
that significant modification procedures must be followed. If significant modification
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procedures apply, the source may no longer operate out of compliance with its approved
permit and conditions.
2.3.3 Significant Permit Modifications
Significant permit modifications are required for major changes to a part 70 permit
that do not qualify as minor permit modifications or administrative amendments. Changes
that are required to be processed as significant modifications include any significant change
to or relaxation of existing monitoring, reporting, or recordkeeping permit terms or
conditions; Title I modifications; and changes that are likely to affect the determination of a
source's compliance with emission limitations and other permit terms and conditions. An
example of a relaxation in a monitoring requirement would be to switch from direct
measurement of emissions to fuel sampling and analysis (e.g., from emissions monitoring of
sulfur dioxide to sampling and analyzing coal sulfur content).
The review procedures for significant permit modifications are similar to those for
permit issuance, including requirements for an application, public participation, and review
by affected States and EPA. The permitting authority must provide at least 30 days for
public comment and at least 30 days advance notice of any public hearing. The EPA
requires that State programs approve or deny the majority of significant modification
applications within 9 months after receipt of a complete application because most significant
modifications will not be complex or require comprehensive analysis.
2.4 ALTERNATIVE OPERATING SCENARIOS/FLEXIBLE PERMIT CONSTRUCTION
Alternative operating scenarios are generally considered to be one form of operational
flexibility. Section 70.6(a)(9) provides for the inclusion hi permits of terms and conditions
for reasonably anticipated operating scenarios that are identified by the source in its
application. Section 70.5(c)(7) allows sources to submit additional information as determined
to be necessary by the permitting authority to define and evaluate the alternative operating
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scenarios or to define the terms and conditions necessary for these scenarios. It is important
for sources and permitting authorities to understand the benefits and limitations of including
alternative operating scenarios in permits. To the extent that changes over the life of the
permit can be anticipated and described, a source can significantly increase its operational
flexibility and avoid unnecessary permit changes if it creatively develops alternative operating
scenarios in its permit application. In so doing, the source can build in the flexibility that it
may need for economic or other business reasons, provided it meets all applicable
requirements. Alternative operating scenarios are also of significant importance to permitting
authorities because a well-thought-out permit application and permit can reduce or eliminate
subsequent unnecessary permit changes. It is sound planning on the part of permitting
authorities to help sources understand the requirements and benefits of alternative operating
scenarios.
The permitting authority must review the scenarios and may approve those that meet
all applicable requirements, including part 70 requirements. Because the scenarios will have
been approved by the permitting authority and incorporated into the permit, no permit
revision is necessary to switch from one scenario to another. The source is required by
§70.6(a)(9)(i) to record contemporaneously in a log at the facility the scenario under which it
is operating. The permitting authority may extend the permit shield (see Section 2.5) to
cover the terms and conditions of the permitted alternative operating scenarios in accordance
with §70.6(a)(9)(ii).
An example of an alternative operating scenario would be including different
production programs at batch-type plants, such as pharmaceutical manufacturers, in a permit.
Another example would be including different monitoring protocols to be used to demonstrate
compliance when operating under different programs. This example is of particular
importance in light of the enhanced monitoring protocol (EMP) requirements of part 64
(proposed in October 1993). Enhanced monitoring protocols must be included for each
limitation or standard in the permit, and changes to an EMP not provided for in the permit
would constitute a significant permit modification. However, by including alternative EMP's
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in the original permit application, a source can have the EMP's approved as alternative
operating scenarios. This up-front planning will provide additional flexibility to the source
and avoid the need for the permitting authority to conduct additional reviews and significant
permit modification processes.
2.5 PERMIT SHIELD
States may include a permit shield in a source's permit under §70.6(f). Under this
shield, the source is deemed to be in compliance with all applicable provisions of the Act, as
long as it is complying with all terms and conditions in the permit. For the permit shield to
be in effect, the permit must include all applicable provisions of the Act and expressly state
that a permit shield exists.
There are certain provisions to which the permit shield does not apply under part 70.
For example, the shield does not apply to provisions related to Title IV of the Act, nor does
it apply to changes made under the administrative amendment and minor permit modification
procedures. Similarly, the shield does not prohibit the agency from modifying the permit to
incorporate new requirements that are promulgated after the permit is issued. In fact,
§70.7(f)(l)(i) requires that permits be reopened to add new requirements if the permit has
three or more years remaining term and the effective date of the new requirement is before
the expiration date of the permit.
2.6 INSIGNIFICANT ACTIVITIES
State permit programs may exempt insignificant activities and emission levels,
provided these exemptions do not interfere with the determination or imposition of applicable
requirements or the calculation of fees. Insignificant activities may be exempted based on de
minimis thresholds, such as size, emission levels, production rates, or other criteria as
approved by EPA. States may also exempt entire source categories, such as space heaters.
Sources with activities that are exempt due to size, emission levels, or production rates must
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include a list of all such activities, emissions, and units with their original application. For
exemptions that apply to an entire source category of activities, the application need not
contain any information on such activities. Changes involving insignificant activities would
not be subject to requirements for permit revisions, provisions for operational flexibility, or
notice requirements for off-permit changes. However, sources must include a list of all
exempted activities with any proposed change.
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3.0 STEP-WISE METHODOLOGY FOR IDENTIFYING
AND CATEGORIZING OPERATING CHANGES
One of the most difficult tasks for the permit reviewer will be determining which
requirements should be used to process a proposed operating change from a source.
Figure 3-1 (a) and (b) is a flowchart that may assist the reviewer in identifying and
categorizing changes requested by sources. The flowchart is blocked off and labeled to
delineate each permit revision process. Each block is labeled with a letter in the upper left
corner for quick reference, as shown below:
A. ALTERNATIVE OPERATING SCENARIO;
B. OFF-PERMIT CHANGE;
C. OPERATIONAL FLEXIBILITY;
D. ADMINISTRATIVE AMENDMENT;
E. MINOR PERMIT MODIFICATION;
F. SIGNIFICANT PERMIT MODIFICATION.
Following the flowchart in Figure 1, the reviewer will first determine if the change
pertains only to the acid rain portion of the permit. If so, it is governed by the acid rain
provisions in parts 72 through 78 and cannot be processed under part 70. Next, the reviewer
will determine if the change is an alternative operating scenario listed in the permit, an off-
permit change, or a change covered under operational flexibility; these changes do not
require permit revisions. If the change does not meet any of the above criteria, the reviewer
will determine if the change is considered an administrative amendment or a minor or
significant permit modification. The remainder of this section describes the step-wise
methodology in more detail. It is important to note that reviewers may use more stringent
permit revision procedures than those required by part 70 and shown in the flowchart. For
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pwmit?
Do** (h* chang* contrav*n* a
t*d*raly* *nforc*ab.* monitoring,
r*cordk**ping, reporting, or compliance
certification r*quir*m*nl7
DOM in* chang* cootrav»o»
sptdflc pwmit i»rms or mak* thwn
No
j Nopmi..tr«v4»lonltFi.>CM»»aly-*nbr<»*U* •nluion* cap?
No
c
Con«no»«i^ ngu*a-l(b)
Figure 3-1 (a). Step-Wise Methodology for Identifying and Categorizing
Proposed Changes (Permit Revisions Not Required).
3-2
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c
ConHnuKl tan Rgura >1(«)
D ADMINISTRATIVE AMENDMENT
DOM the change
• Correct typographical error*
• Chang* addrMeM or telephone
number*
* Provide similar minor
administrative change*
• Require more (recent
monitoring or reporting?
DOM the change register a change of
operational cento)?
No
DOM tfw change incorporate PSD/NSR
requirement* into the part 70 permit?
Doe* the change address other type* of
change* that we approved as
administrative?
E I MINOR PERMIT
MODIFICATION
SIGNIFICANT
L—' PERMIT
MODIFICATION
•pprovat
Doe* the change meet (he
State's criteria for dgnilcant
r No
DOM Ihe change
• violate any appicafale require-
ment* or standards;
• Significantly change or relax
monitorhg, reporting, record-
keeping or com ptianc*
certification requirements; or
• Establish or change a case-by
csoe imit or standard?
No
DOM the change establish or
change a term or conation that
• Ha* no underlying appicaUe
requirement and
• The source ha* assumed to
avoid an otherwise applicable
requirement?
No
I* Ihe change a TIM I
m
-------
example, a change that is allowed under the operational flexibility provisions may be
processed as a minor permit modification.
3.1 REVIEW CHANGE AGAINST EXISTING PERMIT
When a proposed operational change is received from a source, the reviewer should
first review the change against the terms and conditions of the existing permit. Having a
firm understanding of the origin and authority of existing permit terms and conditions, the
applicable requirements, emissions of regulated pollutants, restrictions on the potential-to-
emit for each pollutant, and other relevant facts will provide the reviewer with an
understanding of why the relevant information is in the existing permit and the extent to
which the existing permit presents a barrier to the proposed change. Next, the reviewer
should skim through the proposed change for key information, such as whether it is a new
source, the addition of a new unit, or a change in a process or method of operation at an
existing unit. The reviewer should also determine the source category affected, how
emissions are affected, and if any new pollutants are emitted. Having gained a general
knowledge of the source, the existing permit, and the proposed change, the reviewer is ready
to identify the permit revision process required by the proposed change.
3.2 TERMS AND CONDITIONS THAT MAY PROHIBIT A PROPOSED CHANGE
When a proposed operational change is received from a source, the reviewer must
determine whether the change is allowable, identify the type of change, and follow correct
procedures to process the change. A proposed change may be prohibited due to one or more
of the terms and conditions in the existing permit. A proposed change may also be
prohibited by the approved State permit program. In many cases, prohibitions may be
readily discernable from an examination of the source's existing permit, the State permit
3-4
-------
program requirements, and the proposed change. In other cases, the reviewer will need to
conduct a detailed evaluation.
3.3 CHANGES THAT CAN BE MADE WITHOUT A PERMIT REVISION
Under part 70, several types of changes may be made at a permitted facility without a
permit revision. These changes fall into the following categories:
1. Alternative operating scenarios under §70.6(a)(9);
2. Off-permit changes under §70.4(b)(14); and
3. Operational flexibility under §70.4(b)(12).
The following paragraphs discuss how to identify and categorize changes that do not require
permit revisions using the flowchart in Figure 3-2. Figure 3-2 shows only the portion of the
overall flowchart that involves non-permit revision changes.
3.3.1 Alternative Operating Scenarios
When a request for a change is received that does not qualify as an administrative
amendment, the reviewer should determine if the change is covered by an alternative
operating scenario listed in the permit. Sources are not required to contact the permitting
authority if they intend to switch between alternative operating scenarios in their permit, and
no action is required by the permitting authority. If the change is not covered by an
alternative operating scenario, the reviewer should proceed to "B~Off-Permit Changes" in
the flowchart.
3.3.2 Off-Permit Changes
If the State prohibits off-permit changes, the reviewer should proceed directly to
"C~Operational Flexibility" in the flowchart. Otherwise, the reviewer should determine if
3-5
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ALTERNATIVE OPERATING
SCENARIO
...
\ Notification of the change Is not
| necessary; however, the facility may
j be requfred to maintain a log of such
I changes.
•
Yes
Is the change an alternative operating scenario
listed in the permit?
OFF-PERMIT CHANGE
Is the change addressed or
prohibited by the permit?
The change qualities as an
off-permit change. No permit
revision is necessary.
Yes
Does the change meet all
applicable requirements and NOT
violate any permit term?
C OPERATIONAL FLEXIBILITY
Does the change exceed the
emissions allowable under the
permit?
Yes
Does the change contravene a
federally- enforceable monitoring,
recordkeeping, reporting, or compliance
certification requirement?
Yes
Yes
No
Does the change contravene
specific permit terms or make them
inapplicable?
r
No
No
Yes
: No permit revision is necessary. The
[ change Is covered by the operational
j flexibility provisions. Seven days
advance notice of the change is
required.
does the change involve emissions trading
within the facility based on the applicable
SIP?
Yes
No
Does the change involve emissions trading
within the facility provided by the permit,
solely for the purpose of complying with a
federally-enforceable emissions cap?
No
Figure 3-2. Changes Not Requiring a Permit Revision.
3-6
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the change is addressed or prohibited by the permit. If not, and the change meets all
applicable requirements of the Act and does not violate any permit term or condition, the
change qualifies as an off-permit change. If the change does not qualify as an off-permit
change, the reviewer should proceed to "C~Operational Flexibility" in the flowchart.
3.3.3 Operational Flexibility
To qualify under operational flexibility, the change must not exceed the emissions
allowable under the permit and must not be a modification under Title I (see Appendix A).
Also, the change must fall into one of the following categories:
1. The change contravenes a permit term other than a federally-enforceable
monitoring, recordkeeping, reporting, or compliance certification requirement;
2. The change addresses emissions trading to meet SIP limits where the SIP provides
for such trading on 7 days notice in cases where trading is not already provided for in the
permit; or
3. The change addresses emissions trading to comply with a federally-enforceable
emissions cap established in the permit that is independent of or more strict than otherwise
applicable requirements.
If the proposed change does not meet any of these criteria, the reviewer should proceed to
"D~Administrative Amendment" in the flowchart.
3.4 ADMINISTRATIVE AMENDMENTS
\
Administrative amendments are typically the easiest type of permit revision to
identify. The following paragraphs discuss how to identify administrative amendments using
the flowchart in Figure 3-3, which shows only the portion of the overall flowchart that
involves administrative amendments.
3-7
-------
ADMINISTRATIVE AMENDMENT
Yes
Obtain b«far»
proceeding,
Follow Adrrtnlstratlv*
procedures
Yes
Yes
No
Has a written agreement
transferring permit
responsibility, coverage,
and liability to the new
permittee been submitted
to the permitting authority?
Yes
Is the state NSR Program
EPA-approved and contain
compliance and procedural
requirements substantially
equivalent to §§ 70.6, 70.7
and 70.8?
Yes
No
Yes
Does the change
• Correct typographical errors
• Change addresses or telephone
numbers
• Provide similar minor
administrative changes
• Require more frequent
monitoring or reporting?
No
Does the change register a change of
company name, ownership or
operational control?
No
Does the change incorporate PSD/NSR
requirements into the part 70 permit?
No
Does the change address other types of
changes that are approved as
administrative?
J No
Figure 3-3. Administrative Amendments.
3-8
-------
First, the reviewer should determine if the change corrects typographical errors in the
permit, changes an address or telephone number of a person listed in the permit, requires
more frequent monitoring or reporting, or addresses similar minor administrative changes.
All of these types of changes may be processed as administrative amendments.
Next, the reviewer should determine if the source is registering a change in the
ownership or operational control of the facility. If so, the request should be accompanied by
a written agreement transferring permit responsibility, coverage, and liability to the new
permittee. (This written agreement must be received by the permitting authority before the
revision can be processed.) This type of change should be processed as an administrative
amendment.
Then, the reviewer should determine if the proposed change incorporates prevention
of significant deterioration (PSD)/NSR requirements into the permit. Before processing this
type of permit revision as an administrative amendment, the reviewer should ensure that the
State NSR program is EPA approved and contains compliance and procedural requirements
substantially equivalent to §§70.6, 70.7 and 70.8. If the State NSR program does not have
these "enhancements," the proposed change must be processed as a minor or significant
modification, and the reviewer should proceed with "E~Minor Permit Modifications" in the
flowchart.
Finally, the reviewer should examine their State permit regulations to determine if
they contain any other types of changes that have been approved to be processed as
administrative amendments. If the proposed change addresses any of these State criteria, the
change qualifies as an administrative amendment.
If the proposed change does not meet any of the criteria discussed above for an
administrative amendment, the reviewer should proceed with "E~Minor Permit
Modification" in the flowchart.
3-9
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3.5 MINOR PERMIT MODIFICATIONS
After eliminating the possibility of an administrative amendment or a change that does
not require a permit revision, the reviewer should determine if the change is a minor permit
modification. Because of the nature of minor modifications and the gatekeeper criteria, the
reviewer should evaluate the proposed change through the screening elimination process
described below. The flowchart in Figure 3-4, which shows only the portion of the overall
flowchart that involves minor and significant permit modifications, illustrates this screening
process. The source should have already gone through a similar evaluation/screening process
to conclude that the modification meets the requirements for processing under minor
modification procedures. The reviewer will independently determine whether the source
correctly concluded that the proposed change is a minor modification. Throughout the
process, the reviewer should determine whether the source has submitted sufficient
information to evaluate the change. If additional information is needed by the reviewer to
complete the determination, that information should be obtained before proceeding further in
the process.
First, the reviewer should determine if the change involves economic incentives,
marketable permits, or emissions trading and if these provisions are explicitly provided for in
the SEP or another FJ>A approved program. If so, the change may be processed as a minor
permit modification.
Next, the reviewer should evaluate the change against the gatekeeper criteria in
§70.7(e)(2)(i). The reviewer should determine if the change:
1. Violates any applicable requirements or standards identified in the original permit
and permit application or elsewhere;
2. Significantly relaxes or changes monitoring, reporting, recordkeeping, or
compliance certification requirements (e.g., a significant change in the enhanced monitoring
protocol for an emission unit);
3-10
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MINOR PERMIT
MODIFICATION
No
Does the change Involve the
use of
• Economic Incentives
• Marketable permits
• Emissions trading
Yes
Are such procedures
explidty provided for In the
SIP or other EPA
requirements?
FottowMlnof PwmH •
Madlflcatkm j
l™L _ i
No
SIGNIFICANT
PERMIT
MODIFICATION
, Yes
1 Follow Significant Parmlt j
i Modification procedures,
i The chang» cannot violate
I applicable roqulremanis,
and cannot be
j ImplMwnttdwtthout i
| parmB mrfaw and j
| approval.
I
wans :
* i
Does the change meet the
State's criteria for significant
modifications?
T
No
.Yes
Does the change
• Violate any applicable require-
ments or standards;
• Significantly change or relax
monitoring, reporting, record-
keeping or compliance
certification requirements; or
• Establish or change a case-by-
case limit or standard?
No
, Yes
Does the change establish or
change a term or condition that
• Has no underlying applicable
requirement, and
• The source has assumed to
avoid an otherwise applicable
requirement?
T
No
Yes
Is the change a Title I
modification?
No
{ Follow minor pctmtt
[ modlflcrtlon
I prac«dura*
Figure 3-4. Minor and Significant Permit Modifications.
3-11
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3. Establishes or modifies any case-by-case limit or standard (e.g., a case-by-case
MACT determination under §112[g] of the Act or an equivalency determination for RACT
under Title I of the Act);
4. Establishes or changes a permit term or condition for which there is no
corresponding applicable requirement and that the source has assumed to avoid an applicable
requirement to which it would otherwise be subject;
5. Is a Title I modification; or
6. Is required by the State program to be processed as a significant modification.
If any of these gatekeeper criteria are violated, the reviewer should proceed to
"F~Significant Permit Modification."
3.6 SIGNIFICANT PERMIT MODIFICATIONS
Following the flowchart in Figure 3-4, the reviewer may determine that a proposed
change is a significant permit modification by process of elimination. As with minor permit
modifications, the source should have already determined that the change meets the
requirements for processing under significant permit modification procedures. The reviewer
will independently determine whether the source correctly concluded that the proposed
change is a significant modification. If the source did not originally classify the change as a
significant modification in their application, additional information from the source may be
necessary to process the change.
3.7 CHANGES THAT CANNOT BE MADE UNDER PART 70
Title V permits must assure compliance with all applicable requirements of the Act,
including applicable SIP requirements. Therefore, no changes can be made that would
modify or otherwise override the applicable SIP. If the SEP does not authorize changes from
unit-specific emission limits or caps contained in the SIP without a SEP revision, the
3-12
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operational flexibility provision cannot authorize such changes; no permit revision is possible
until the SIP is revised.
Also, violations of other applicable requirements cannot be allowed under the permit.
Such violations include lowering an applicable new source performance standard (NSPS)
control efficiency, allowing emission limitations above increment ceilings, and changing a
MACT determination made under §112 of the Act or a case-by-case MACT determination
made by the State. Also, proposed changes to the acid rain portion of the permit cannot be
made under part 70 and are governed by regulations promulgated under Tide IV of the Act.
3-13
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4.0 APPLICATION OF STEP-WISE METHODOLOGY TO CASE STUDIES
This section presents case studies for the following four industries: (1) vehicle
manufacturing, (2) pharmaceutical manufacturing, (3) pulp and paper manufacturing, and
(4) synthetic organic chemical manufacturing. Each case study includes background
information on the source and several scenarios of proposed changes. The reader should
determine the category of change for each scenario using the step-wise methodology
presented in Section 3.0. Then, the reader should compare their solutions to the solutions
provided under each scenario description.
4.1 VEHICLE MANUFACTURING CASE STUDY
Background. A hypothetical vehicle manufacturing facility consists of a plastic parts
line, pretreatment and assembly operations, two surface coating lines, and a small boiler for
heating. Trucks are assembled at the plant. The truck body parts (e.g., fairings, hoods,
fenders, and chassis) are manufactured by outside vendors and transported to the plant.
The plant is divided into several sources, and it is a major source of VOC emissions.
Each of the two surface coating lines has allowable emissions of VOCs of 249 tons per year
(tons/yr). The second line is newer than the first, and its VOC limit was taken by the source
to avoid NSR review, which was possible because the first line is still a minor source.
There are no other emissions considered major according to major source definitions under
the Act. The small boiler currently burns only natural gas and is not subject to any NSPS.
The plant is located in an attainment area for all pollutants. The State has no
case-by-case control technology analysis requirements outside of the NSR rules for major
sources for pollutant increases. The State operating permit program trigger level for an
emissions increase requiring a significant permit modification is 40 tons/yr for VOC, which
is the same as the significance level for emissions triggering NSR evaluation.
4-1
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Scenario 1. The facility wishes to make a process change in the newer surface
coating line to allow painting of some of its trucks with a clear coat following the topcoat. A
new paint spray booth will be added to the surface coating line. Particulate matter emissions
will increase very little and will not affect any applicable requirements. This process change
was not anticipated at the time of permit issuance. Actual VOC emissions from the newer
surface coating line before the change, based on testing and engineering calculations, are
220 tons/yr. With the additional volume of coating product to be used, VOC emissions are
estimated to increase by 45 tons/yr. Categorize the change.
Solution. The VOC emissions increase for State/NSR consideration is calculated as
follows:
Potential to emit - Actual emissions = Emissions increase for State/
after change before change NSR consideration
265 tons/yr - 220 tons/yr = 45 tons/yr
The estimated emissions after the change (265 tons/yr) will exceed the allowable limit of
249 tons/yr, and the emissions increase will exceed the State and NSR significance levels of
40 tons/yr for VOC. Therefore, the proposed change would require a significant permit
modification.
Scenario 2. The facility wishes to make a process change to the newer surface
coating line similar to that in Scenario 1 (i.e., an additional coat), except that the estimated
increase in VOC emissions is only 25 tons/yr. The facility anticipated the need to add the
third coat when applying for the initial permit, and the permit contains a condition specifying
that two coats shall be applied and an alternative condition specifying that three coats may be
applied. Categorize the change.
Solution. The VOC emissions increase of 25 tons/yr is below the State and NSR
significance levels of 40 tons/yr. To avoid the necessity of NSR evaluation, the
4-2
-------
facility has demonstrated that VOC emissions from the additional spray booth would
not exceed 40 tons/yr at the maximum coating application rate. (Note that without
such a demonstration, a permit restriction may be required to limit emissions from the
new spray booth below 40 tons/yr; any permit restriction taken specifically to avoid
triggering NSR evaluation must be obtained through a significant permit modification
because of the pan 70 gatekeeper criteria.)
Because the facility anticipated the need to add a third coat during the initial
application process and the permit contains this alternative, the proposed change would be
considered an alternative operating scenario. No notification is necessary; however, the
facility must record in a log at the facility the scenario under which it is operating.
Scenario 3. The facility wishes to make a process change similar to that in
Scenario 1 (i.e., an additional coat), except that the process modification would apply to the
older surface coating line. For this older line, the 249 tons/yr VOC limit was not taken for
the purpose of avoiding NSR. Actual VOC emissions are 245 tons/yr. The VOC emissions
from the older line are estimated to increase by 25 tons/yr due to the additional coat
application. Categorize the change.
Solution. The estimated emissions after the change (270 tons/yr) will exceed the
allowable limit. The VOC emissions increase is 25 tons/yr, which is below the State
and NSR significance levels of 40 tons/yr. Therefore, the proposed change would
require a minor permit modification.
Scenario 4. The facility wishes to make a process change to the newer surface line
similar to that in Scenario 1 (i.e., an additional coat), except that the actual emissions before
the change are only 200 tons/yr. With the additional volume of coating product to be used,
VOC emissions are estimated to increase by 45 tons/yr.
4-3
-------
Solution. The estimated emissions after the change (245 tons/yr) will not exceed the
existing allowable limit of 249 tons/yr. The emissions increase of 45 tons/yr exceeds
the 40 tons/yr trigger for State and NSR evaluation; therefore, the proposed change
would require a significant permit modification.
Scenario 5. A variety of coating products (most related to color selection) are
sprayed on the trucks. Maximum potential VOC emissions from each of the facility's
surface coating lines were estimated in part by assuming that only the paint of highest VOC
content (by weight) would be used on the coating line. The permitted VOC emission limit
(249 tons/yr from each line) is based in part on that maximum potential. The facility plans
to use a new topcoat that contains an even higher VOC content than that of any paint
currently used. On a unit basis, use of the new topcoat will cause a decrease in VOC
emissions. Use of the new topcoat will result in no new applicable requirements. The
permit currently restricts the VOC content of the coating by specifying the maximum pounds
of VOC per gallon of coating that may be used. Categorize the change.
Solution. Because the permit restricts the VOC content of the coating, use of the new
topcoat would contravene that permit term. Therefore, the proposed change would be
considered a Section 502(b)(10) change, even though the change would not result in
any emissions increase. This change is within the realm of operational flexibility,
requiring 7-days notice to the State.
Scenario 6. The small boiler, a 10 million British thermal unit per hour (MMBtu/hr)
commercial unit, at the facility's heat plant currently uses only natural gas as fuel. It has
become economically attractive for the facility to have the flexibility of using an alternative
fuel (i.e., distillate oil) during certain times of the year. The plant operates 8,760 hours per
year, and VOC emissions from the boiler are 200 pound per year (Ib/yr) if only natural gas
is fired. If distillate oil is fired instead, VOC emissions would be as low as 120 Ib/yr. Any
use of distillate oil will result in a decrease in VOC emissions. However, emissions of other
criteria pollutants would increase, and the boiler would become subject to an NSPS. New
4-4
-------
applicable requirements under the NSPS include a sulfur dioxide (SC^) standard of
0.5 Ib/MMBtu and a PM standard of 20 percent opacity (no emission limit), as well as
additional monitoring requirements. A comparison of emissions between natural gas and
distillate oil firing is shown in Table 4-1. The State operating permit program and NSR
trigger levels for other criteria pollutants are the same as those for VOC (40 tons/yr).
Categorize the change.
TABLE 4-1. COMPARISON OF EMISSIONS DUE TO
PROPOSED FUEL CHANGE (tons/yr)
Pollutant
PM
SO2
CO
NOX
VOC
Emissions due to
firing natural gas1
0.2
0.03
0.83
4.17
0.11
Emissions due to
firing distillate oir2
0.6
22.2
2
6.3
0.068
Increase due to
firing distillate oil
0.4
22.17
1.17
2.13
-0.042
Based on 10 x ICr Btu/hr heat input, 1,050 Btu/fr of natural gas, at 8,760 hr/yr. Emission factors from
AP-42, 1.4-2.
2 Based on 10 x 106 Btu/hr heat input, 140,000 Btu/gal distillate oil of 0.5% sulfur content (by weight), at
8,760 hr/yr. Emission factors from AP-42, 1.3-2.
Solution. According to Table 4-1, the emissions increase due to changing Juels does
not trigger the State or NSR significance levels to require a significant permit
modification. However, in the case of any Title I modification (which includes NSPS),
permit modifications cannot be made through the minor permit modification
mechanism. Therefore, the boiler fuel change would require a significant permit
modification.
4-5
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4.2 PHARMACEUTICAL MANUFACTURING CASE STUDY
Background. Figure 4-1 presents the layout for a hypothetical pharmaceutical
manufacturing facility. This hypothetical facility consists of a chemical synthesis operation
with the following characteristics:
1. Five tank farms with a total of 20 storage tanks ranging in size from
30,000 gallons (gal) to 75,000 gal;
2. Two large residual oil-fired steam boilers, each rated at 100 MMBtu/hr;
3. Three batch process units, each consisting of a dryer, a reactor, a distillation unit,
an in-process holding tank, two condensers, an extractor, a centrifuge, and a crystallizer
(Figure 4-2 presents the equipment layout for a typical pharmaceutical batch process);
4. One tablet coating operation; and
5. Wastewater treatment.
The facility is located in an attainment area for all pollutants. The State operating
permit program trigger level for an emissions increase requiring a significant permit
modification is 20 tons/yr for VOCs. Table 4-2 presents actual VOC emissions for each area
of the plant, as well as the permitted emission limits for each area. Table 4-3 presents actual
emissions, control devices, and control levels for process equipment for one batch process
unit. Emissions from each batch process unit are equal. Both boilers are subject to an NSPS
(subpart D^), and 12 of the storage tanks are subject to the volatile organic liquid (VOL)
Storage NSPS. No NESHAP's apply to the facility. Emission limits for the batch areas
were based on maximum expected capacities for all products manufactured in these areas.
Scenario 1. The facility wishes to expand production to accommodate an increase
market demand for existing product X. This change does not require an equipment change
nor a change in the type of raw material used in the plant. The only operational change is an
increase in the frequency of the batch process making product X. Assume that an increase in
4-6
-------
000
Tank Farm [A]
ooo
Combustion
Units
oo
Tank Farm
QO
Tank Farm C
ooo,, o o
Tank Farm
OO
Tank Farm
O
Tablet
Coating
Wastewater
Treatment f E
Process
Unit
Process
Unit
Process
Unit
LEGEND
• Plant Boundary
Plant Units/Areas
Figure 4-1. Configuration of a Hypothetical Pharmaceutical Manufacturing Facility.
4-7
-------
Solids
Solvent
Vent
Vent
T
H2O
Solvent Vent
Solvent
Solvent
00
t^i i>r
Reactor
Holding
Tank
Receiver w
Solvent
Distillation
Crystallizer
Vent
1
-Product
Typical Cycle 1/24 hours
Solvent
Figure 4-2. Equipment Layout for Typical Pharmaceutical Batch Process.
-------
TABLE 4-2. ACTUAL AND PERMITTED EMISSIONS FOR HYPOTHETICAL
FACILITY (tons/yr)
Equipment component
Tank farms (5)
Batch process units (3)
Steam boilers (2)
Tablet coating
Wastewater treatment
Total emissions
Actual VOC emissions
6.6
13.8
75.0
4.0
20.0
119.4
Permitted VOC emissions
8.0
16.0
80.0
5.0
25.0
134.0
TABLE 4-3. ACTUAL EMISSIONS FOR ONE BATCH PROCESS UNIT
Batch process equipment
component
Reactor
Dryer
Distillation column
Centrifuge
Crystallizer
In-process tank
Total Emissions
Control device
Surface
condenser
Surface
condenser
None
Surface
condenser
None
None
Percent control
<*)
81
94
—
67
—
—
Actual VOC
emissions
(tons/yr)
0.6
0.3
1.7
0.9
0.7
0.5
4.7
4-9
-------
operating hours for the product X batch process would increase the VOC emissions to
20 tons/yr, which is greater than the permitted level of 16 tons/yr. Categorize the change.
Solution. The VOC emissions increase causes emissions to exceed allowable levels,
but does not trigger NSR. Nor does the emissions increase of 4 tons/yr exceed the
State threshold for significant permit modifications, which is an increase of 20 tons/yr
or more VOC. Therefore, because the proposed change is not a Title I modification
and the net emissions increase does not exceed the State threshold, a minor permit
modification would be required.
Scenario 2. The permit specifies 3 dryers hi the batch process areas that have VOC
emission limits of 16 tons/yr. The facility adds a fourth dryer to improve the ability to
manufacture multiple products simultaneously. The new dryer is controlled by a surface
condenser. Emissions do not increase. Nothing in the permit prohibits the addition of a new
dryer. Categorize the change.
Solution. Because emissions do not increase, the change does not require a Title I
modification. Because the permit does not prohibit the addition of a new dryer, the
proposed change would qualify as an off-permit change.
Scenario 3. The facility wishes to reconfigure existing equipment for new products.
A new type of raw material will be used. Recordkeeping and monitoring are specified in the
permit for the current raw material usage to show compliance with the permit limits. No
recordkeeping and monitoring changes need be made because the same test method used to
monitor the old raw material can be used to monitor the new raw material. A list of
alternative raw materials that may be used for this process is given in the initial permit; the
list includes the new type of raw material that the facility wishes to use. Categorize the
change.
4-10
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Solution. Because the initial permit contains alternative raw materials, and because
use of the new type of raw material is one of those alternatives, the proposed change
would qualify as an alternative operating scenario. No notification is necessary;
however, the facility must record in a log at the facility the scenario under which it is
operating.
Scenario 4. The facility wishes to add a new boiler to accommodate increases in
production. The new boiler has a capacity of less than 10 MMBtu/hr, burns natural gas, and
emits less than 40 tons/yr of NOX. This boiler would be exempt from NSPS requirements.
Assume that the State permitting program exempts gas-fired boilers less than 50 MMBtu/hr
from pre-construction review requirements. Categorize the change.
Solution. The proposed change does not qualify as a Title I modification because it is
exempt from NSPS and pre-construction review requirements. Therefore, the change
would be an off-permit change.
Scenario 5. To improve its manufacturing process, the facility makes
mass-to-formula changes to refine operating conditions (i.e., time or yield). For example,
the facility changes the reactor temperatures, makes slight changes in solvent use, and uses
another separation step to increase the recovery rate. Assume the permit does not specify
mass-to-formula ratios. The emissions do not increase beyond the permitted limits for each
area of the plant. (Assume that the plant checks the possibility of emission increases before
instituting these changes and will not make the change if the permit limits would be
exceeded.) This change would not violate any of the conditions of the permit. Categorize
the change.
Solution. The proposed change would qualify as operating under the current
conditions of the permit; no permit modification would be necessary.
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Scenario 6. The facility wishes to change equipment configurations and raw material
usage to support new products. Currently, the facility uses raw materials A plus B to yield
product C. Product C is then coated using a solvent, which results in VOC emissions of
1 ton/yr. Now the facility wishes to use raw materials A and D to yield new product E.
Consequently, the VOC emissions from the use of the solvent to coat the new product
become 2 tons/yr, which increase VOC emissions in the tablet coating above the permit limit
of 5 tons/yr. However, the use of raw materials A and D lowers VOC emissions in the
batch process area by 1 ton/yr as a result of a lower dryer temperature. There is no net
VOC change in the plant. Permit limits are set to represent plant operation. Categorize the
change.
Solution. The proposed change would fall under emissions trading in the operational
flexibility provision.
Scenario 7. The facility wishes to install a steam stripper that would strip wastewater
streams to achieve waste reduction goals. This change would decrease air emissions by
removing pollutants from the wastewater that would otherwise volatilize and contribute to air
emissions. The overheads from the stripper will be recovered and burned as fuel in the
boilers. The steam stripper is not included in the permit. Nothing in the permit prohibits
steam stripper use, and the change will not result in an increase in boiler emissions (i.e., will
not violate the boiler permit limits). Categorize the change.
Solution. Because emissions do not increase and the change is not prohibited by the
permit, the proposed change would qualify as an off-permit change.
4.3 PULP AND PAPER CASE STUDY
Background. A typical kraft process line in a pulp and fine paper mill is
schematically represented in Figure 4-3. The facility consists of two batch-process pulp
digesting lines - one line receives hardwood and the pther line receives softwood. Total
4-12
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-------
capacity (throughput) is rated at 2,000 bone dry tons per day (BDTD) of pulp through the
two lines. This kraft mill is a major stationary source and is located in an attainment area
for all pollutants.
The permit addresses five air emission areas within the facility; it specifies all control
equipment and operating parameters, fuels that can be burned in the boilers, and capacity of
all equipment listed in the permitted areas. The permitted air emission areas are as follows:
1. Power
-- Main boiler - not subject to NSPS (installed prior to 1971); and
-- Two hog fuel boilers - both subject to NSPS (subpart D).
The permit specifies the control equipment on the boilers, the fuels allowed, and the
firing capacity of the boilers (maximum Btu/hr heat input from each fuel or
combination of fuels).
2. Recovery
- Recovery boiler - not subject to NSPS;
— Smelt dissolving tanks - subject to NSPS (subpart BB):
~ Salt cake transfer and storage system; and
-- Evaporators - subject to NSPS (subpart BB).
3. Pulp Mills, Causticizing, Non-condensible Gas Collection
~ Two digesters and associated brown stock washers - subject to NSPS
(subpart BB). Hardwood digester and washer rated at 800 BDTD; softwood
digester and washer rated at 1,200 BDTD;
-- Non-condensible/low-volume high-concentration (LVHC) gas collection;
- Lime kiln (500 tons/day reburned lime capacity) - subject to NSPS
(subpart BB1:
— Turpentine recovery system (on softwood line with 32,000 gal storage tank) -
subject to NSPS (subpart KbV.
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- Methariol storage tank (20,000 gal capacity) - subject to NSPS (subpart Kb):
and
~ Associated equipment such as lime slakers, burnt lime conveyor, backup rotary
lime kiln, lime mud filter system, and wood transfer system - not subject to
NSPS.
4. Bleach Plants
- Bleaching towers;
~ Washers and filtration tanks; and
— Chlorine dioxide generator (35 tons/day).
5. Wastewater
~ Condensate stripper system - subject to NSPS (subpart BB): and
~ Wastewater collection system consisting of wet wells and lifting stations.
The remaining areas of the plant include Fine Paper-Making and Maintenance. This facility
is a major source of criteria pollutants, total reduced sulfur (TRS), and HAPs.
Scenario 1. The State operating permit program trigger level for an emissions
increase requiring a significant permit modification is 5 tons/yr for all pollutants. The
existing permit specifies the exact fuels that can be burned in the hog fuel boiler; that is, the
permit specifies that the hog fuel boilers will bum only hog fuel, coal, No. 6 fuel oil, and
waste and crankcase oils. The hog fuel boiler is subject to NSPS subpart D (for visible
emissions, SC^, PM, and NOX emission limits).
The plant managers have decided to temporarily substitute a portion of the fuels
normally burned in the hog fuel boiler with waste fiber sludge, which is not allowed under
the permit. They conduct a fuel analysis on the waste fiber sludge substitution and determine
that the substitution will not result in an exceedance of the NSPS limits or the State trigger
level for significant permit modifications (i.e., the increase will be less than 5 tons/yr).
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As a result of the change, substantial (but not significant) additions would have to be
made in compliance reporting. The NSPS-required monitoring for the boilers would not
change. However, provisions for burning waste fiber sludge must be added to the permit as
a permit term. Additionally, a fuel analysis must be conducted and the results reported to
verify that the emission changes are negligible and NSPS requirements will be met.
Further, the permitting authority requires a new source performance test and report
for the boiler when firing the waste fiber sludge to demonstrate that the fuel substitution is an
equal emission trade and will not cause the facility to exceed any of the NSPS emission
limits. The new reporting requirements are the same type of reporting that has been done
for the fuels that were initially permitted. However, the new reporting does exceed the level
of reporting changes that qualify for operational flexibility provisions. Categorize the
change.
Solution. Because the new reporting changes are not extensive enough to require a
significant permit modification nor are they minimal enough to qualify under
operational flexibility, the proposed change would require a minor permit
modification.
Scenario 2. The plant has decided to convert one of its pulping lines from a batch
process to a continuous line. This change will require the installation of new equipment,
including a digester and brownstock washers. The new equipment results in a major
modification under NSR and is subject to NSPS (subpart BB) requirements. Categorize the
change.
Solution. Both of these actions constitute Title I modifications. Therefore, the
proposed change would require a significant permit modification.
Scenario 3. To reduce worker exposure to wastewater chlorine/chloroform emissions
from open wastewater sewers, the managers have decided to add a mix box with a stack to
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the acid and caustic sewer junction. The modification results in no emissions change and
only converts a fugitive emissions source to a point emissions source. There are no
underlying applicable requirements governing this change, and the permit does not prohibit
it. Categorize the change.
Solution. Because emissions do not increase and the change is not prohibited by the
permit, the proposed change would qualify as an off-permit change.
Scenario 4. The permit specifies that the brownstock washers will use only raw
water. However, the plant manager decides to substitute clean condensate water for a
portion of the raw water in the pulp washing process in order to reduce emissions from the
wastewater treatment area of the plant. This change would not cause the facility to exceed
the State trigger level for significant permit modification or the NSPS-specified emission
limits for the washers that are in the permit. Categorize the change.
Solution. The proposed change would contravene a permit term that is expressly
detailed in the permit. Therefore, this change can be accomplished under the
Section 502(b)(10) provision of operational flexibility.
4.4 SYNTHETIC ORGANIC CHEMICAL MANUFACTURING CASE STUDY
Background. Regulations that pertain directly to Synthetic Organic Chemical
Manufacturing Industry (SOCMI) sources are the following NESHAP (40 CFR part 61) and
NSPS (40 CFR part 60):
1. Hazardous Organic NESHAP (HON);
2. Equipment Leaks of VOC in the SOCMI (subpart W);
3. SOCMI Air Oxidation Unit Processes (subpart HI); and
4. SOCMI Distillation Operations (subpart NNN).
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In addition, SOCMI sources may be faced with more general regulations such as:
1. PSD restrictions;
2. SIP limitations (if the source is located in a nonattainment area);
3. Other NSPS (e.g., steam generating units, incinerators, and petroleum or VOL
storage);
4. Equipment Leaks NESHAP (40 CFR part 61, subpart V); and
5. Benzene NESHAP for various sources (40 CFR part 61, subparts J, Y, BB,
andFF).
In this hypothetical case, Chemicals A and B, which are of similar chemistry, are
reactants used in a 1:1 ratio to produce Chemical C. The process is further characterized as
follows:
1. The source is already in compliance with the applicable regulations, and
because the facility is a major HAP source, it is already operating under the State-issued
part 70 permit that is more than three years from renewal;
2. The source is located in an attainment area for all pollutants. However, to
avoid PSD applicability, the source has accepted a limit on VOC emissions of 99 tons/yr (a
SOCMI source emitting 100 tons/yr or more is major for PSD);
3. The reference control technologies specified in the HON and the NSPS
governing VOL storage have been applied at the appropriate points and noted in the permit;
4. A State air toxics program exists, which establishes permissible emission levels
for specified HAPs; and
5. All monitoring, testing, recordkeeping, and reporting requirements are stated
in the permit.
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The permit lists the emissions limits shown below along with the actual emissions
from the process:
Pollutant
VOC
HAP
Allowable Emissions (tons/yr)
99
60
Actual Emissions (tons/yr)
85
55
Under the State air toxics program, the source is not allowed to emit more than
30 tons/yr of HAPs from Chemical A and more than 30 tons/yr of HAPs from Chemical B
(but these limits are not federally enforceable). The 55 tons/yr of actual HAP emissions are
emissions of Chemicals A and B from throughout the process, which are also VOCs.
Emissions of the product Chemical C and by-products make up the remaining 30 tons/yr of
the total actual VOCs.
Although the allowable emissions of VOCs are specified in the permit, beyond
requiring the installation of the specified HON and NSPS control technologies, VOC
emission limits are enforced by restricting the use (throughput) of Chemicals A and B. The
emission limit terms are worded as shown in the following excerpt from the permit:
"To comply with this permit and to avoid applicability of PSD, VOC emissions from
permitted points must be less than 99 tons/yr. To assure that emissions are less than
the tons per year limit, the following permit limit (s) must not be exceeded:
a. Total annual usage of Chemical A shall not exceed 2 MMlblyr.
b. Total annual usage of Chemical B shall not exceed 2 MMlb/yr."
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Finally, for the purposes of this case study, the level of emissions increase that
triggers NSR or a significant permit modification as prescribed by the State operating permit
program is 40 tons/yr for VOC's and 10 tons/yr for HAPs.
Scenario 1. The permit specifies the number of chemical storage tanks, the capacity
of each tank, and the chemicals that are allowed to be stored in each tank. The plant
operators decide to replace the storage vessels that hold Chemicals A and B. For each
chemical, three existing vessels are to be replaced by two new ones of the same type with
larger diameters and hence larger capacities. However, the overall storage capacity for each
chemical will remain the same.
Because the tanks that are being replaced comply with the HON storage tank
requirements and because the new tanks are the same type, they also will comply with the
HON requirements. The number of tanks will not necessitate any changes to the HON-based
permit requirements. Although construction of the new tanks will trigger the VOL Storage
NSPS, these requirements are almost identical to the HON and are in some cases more
stringent. Therefore, the new tanks, if the facility continues to operate them hi compliance
with the existing permit, will also comply with VOL Storage requirements. Using AP-42 as
a reference, the operators calculate that there will be no increase in actual emissions (HAP or
VOC) from the larger diameter tanks. However, there is an NSR-calculated VOC emissions
increase of 14 tons/yr (future potential emissions - present actual emissions = 99-85
= 14 tons/yr), unless the facility decides to accept a lower allowable limit on VOC
emissions. Assume the facility takes the lower allowable limit of 85 tons/yr on VOC
emissions, thereby avoiding an NSR-calculated increase in emissions. Categorize the change.
Solution. If the facility takes the lower allowable VOC limit to avoid the Title I
modification, and if the State allows off-permit changes, the proposed change would
qualify as an off-permit change because the existing permit does not address or
prohibit the removal of the three old tanks or the installation of the two new larger
ones for each chemical.
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If the State does not allow off-permit changes, the change is likely to be a
Section 502(b)(10) change because it is not a Title I modification, nor does it cause the
allowable emissions limit to be exceeded. Also, the change does not contravene the express
permit terms that state the number of tanks and the capacity of each tank. Assuming that all
compliance requirements in the permit are stated on a per-tank basis and the SIP does not
have any new or different compliance requirements that would apply given the change in tank
size, the change would not contravene a federally enforceable permit term or condition
regarding monitoring, recordkeeping, reporting, and compliance certification.
The change in the number of tanks would not violate NSPS requirements (VOL
Storage), nor would it violate any NESHAP requirements. The only NESHAP other than the
HON that would potentially apply would be the Benzene Storage NESHAP if either
Chemical A or B were benzene. Because the Benzene Storage NESHAP provisions are
essentially the same as the HON stage provisions, compliance with the existing permit
provision would be compliance with the Benzene NESHAP.
Scenario 2. The pilot plant indicates that changing the ratio of Chemical A to
Chemical B in the reaction may improve the yield of Chemical C in the product mixture.
Specifically, they wish to increase the amount of Chemical A by 20 percent and decrease
Chemical B by the same amount. The plant operators decide to implement the process
modification and project that after the change, they will use 2.4 MMlb/yr of Chemical A and
1.6 MMlb/yr of Chemical B.
The planned change would contravene the permit term limiting the annual usage of
Chemical B. However, the operators calculate that because Chemicals A and B are of
similar chemistry, the difference between the reactants' vapor pressures is slight and there
would not be an appreciable change in overall VOC emissions resulting from the substitution.
Likewise, although more Chemical C will be produced, the increased emissions of
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Chemical C will be completely offset by the decrease in by-products and excess reactants in
the product stream. Categorize the change.
Solution. It may seem that even though the process change contravenes an express
permit term, because the change does not exceed the emissions allowable under the
permit (in terms of total emissions), it should be possible to process this change under
Section 502(b)(10) without requiring a permit revision. However, the permit term that
would be violated is a compliance condition the source assumed to avoid an
applicable requirement (i.e., PSD applicability). The limit on the annual usage of
Chemical A is a federally enforceable emissions cap assumed to avoid classification as
a modification under Title I. Violating such compliance terms is not permitted under
Section 502(b)(10), nor is it permitted under the minor permit modification provisions.
Hence, even though emissions should not increase, this change must be processed as
a significant permit modification.
During the permit modification process, the source could request that provisions be
placed in the permit that allow for emissions trading within the facility, which could
accommodate this type of change in the future. Or, the source could request an alternative
restriction (other than ones based on throughput) that would still demonstrate compliance
with an emissions cap to avoid PSD applicability. This situation is described in the next
scenario.
Scenario 3. The facility's permit limits emissions of VOC's from the process
described in Scenario 2 by restricting the production rate of Chemical C as follows:
"To comply with this permit and to avoid applicability of PSD, VOC emissions from
permitted points must be less than 99 tons/yr. To assure that emissions are less than
this limit, the following permit limit must not be exceeded:
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a. "Total annual production of the Chemical C process train shall not exceed
3.5 MMlb/yr."
Changing the ratio of Chemical A to Chemical B in the reaction is expected to
increase the production of Chemical C, but not sufficiently to violate the restriction on
production rate. However, the operators expect increased use of Chemical A to result in
increased Chemical A emissions above the express permit term limiting emissions of
Chemical A as a HAP under the State air toxics program. Categorize the change.
Solution. The permit term that would be violated is not associated with any
applicable requirement; it is a State limit which is not federally enforceable.
Therefore, the proposed change would be considered a Section 502(b)(10) change.
This change is within the realm of operational flexibility, requiring 7-days notice to
the State.
Scenario 4. As a result of the decision to implement the process change described in
Scenario 2, the operators want to keep more Chemical A on hand. They decide to switch the
service of a smaller Chemical B storage vessel (one other than those replaced in Scenario 1)
to hold Chemical A. As described before, Chemicals A and B are similar chemicals, and no
increased emissions are expected from the vessel by making the switch hi service. The
vessel is noted in the operating permit as follows:
"One Chemical B storage tank (10,000 gallons capacity, ID No. 5)."
The HON provisions for storage vessels are the only requirements applicable to this
process point. The HON specifies the control technologies that must be used; it does not
restrict the type of chemical that can be stored. Categorize the change.
Solution. Because the permit does not bar the operators from storing other chemicals
in this vessel, the proposed change would qualify as an off-permit change.
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If the permit had noted the vessel as: "One storage tank for Chemical B only . . .,"
changing its service would be considered as contravening an express permit term. However,
the compliance term is not associated with an applicable requirement and is not
federally-enforceable; in this case, the proposed change would be accomplished through
operational flexibility.
Scenario 5. By changing the ratio of Chemical A to Chemical B, not only is the
product yield of Chemical C enhanced, but the overall product mixture performs in such an
improved way for customers that it is now in dramatically higher demand. To meet the
increased demand, the operators plan to increase the throughput of the process from
50 percent of capacity to 100 percent of capacity. They also decide to switch another similar
process line to the manufacture of Chemical C. Hence, significantly increased VOC and
HAP emissions above NSR levels of significance are expected from the existing process due
to the increased operating rate of the original process and from the new converted process.
Categorize the change.
Solution. Because the proposed changes would trigger NSR levels of significance
(i.e., Title I modification), a significant permit modification would be required.
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APPENDIX A. TITLE I MODIFICATIONS
One of the most prevalent "gatekeepers" of permit modification processes is that a
change cannot constitute a modification under Title I of the Act. Title I of the Act includes
several different definitions of Title I modifications, including:
1. New source performance standards (NSPS) under §111 of the Act;
2. New source review (NSR) under part D of the Act;
3. Prevention of significant deterioration (PSD) under part C of the Act;
4. National emission standards for hazardous air pollutants (NESHAPs) under §112
of the Act; and
5. State preconstruction review programs approved in the State implementation plan
(SIP) under §110 of the Act.
It is important to note that EPA is currently in the process of revising the NSR and PSD
regulations. Promulgation of these regulations is scheduled for the fall of 1994.
New Source Performance Standards. The modification provisions of the NSPS program are
based on the following definition of modification from §lll(a)(4) of the Act:
"...any physical change in, or change in the method of operation of, a stationary
source which increases the amount of any air pollutant emitted by such source or which
results in the emission of any air pollutant not previously emitted. "
The general provisions for the NSPS regulations define a modification in §60.2 as:
"...any physical change in, or change in the method of operation of, an existing facility
which increases the amount of any air pollutant (to which a standard applies) emitted
into the atmosphere by that facility or which results in the emission of any air pollutant
(to which a standard applies) into the atmosphere not previously emitted."
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Section 60.14(e) lists the following exceptions to this definition:
1. Maintenance, repair, and replacement which the Administrator determines to be
routine for a source category;
2. An increase in production rate of an existing facility, if that increase can be
accomplished without a capital expenditure on that facility;
3. An increase in the hours of operation;
4. Use of an alternative fuel or raw material if, prior to the date any standard
becomes applicable, the existing facility was designed to accommodate that alternative use
(including conversion to coal that meets the requirements specified in §lll[a][8] of the Act);
5. The addition or use of any system or device whose primary function is the
reduction of air pollutants (except if the system is less environmentally beneficial); and
6. The relocation or change in ownership of a stationary source.
These provisions contain a two-step test for determining whether activities at an existing
facility constitute a modification subject to NSPS requirements. In the first step, the
reviewing authority determines whether a physical or operational change will occur. If so,
the reviewing authority proceeds to the second step, which is to determine whether the
physical or operational change will result in an emissions increase over baseline levels.
Emission increases are determined by changes in the hourly emission rates at maximum
physical capacity, expressed in kilograms per hour. In addition, a modification will be
considered a "reconstruction" and the source or emissions unit considered "new" and subject
to NSPS if the physical or operational change costs more than 50 percent of the replacement
cost of the affected facility, generally excluding the cost of air pollution control systems not
integral to process equipment, regardless of whether an emissions increase occurs.
New Source Review. Requirements related to modifications for the NSR program are
contained in §§171 and 182 of the Act, as well as in part 51. Section 171(4) defines
modification by referencing the NSPS definition for modification in §lll(a)(4).
Modifications to sources subject to the minor NSR program under §§51.160 through 51.162
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and 51.164, are also considered Title I modifications. The NSR provisions contain a two-
step test for determining whether activities at an existing facility constitute a modification
subject to NSR requirements. In the first step, the reviewing authority determines whether a
physical or operational change will occur. If so, the reviewing authority proceeds to the
second step, which is to determine whether the physical or operational change will result in
an emissions increase over baseline levels. The NSR regulations examine total emissions to
the atmosphere, and emissions increases are determined by changes in annual emissions as
expressed in tons per year. Section 51.165(a)(l)(x) exempts from treatment as a
modification a change resulting in a net emissions increase below the following levels:
Pollutant
Carbon monoxide (CO)
Nitrogen oxides (NOX), sulfur dioxide
(862), and volatile organic compound
(VOC)
Lead(Pb)
tons/yr
100
40
0.6
However, §182 of the Act sets lower de minimis levels for various ozone nonattainment
classifications. For example, §182(c)(6) of the Act establishes de minimis levels for ozone
precursors in serious nonattainment areas that limit increases for purposes of Title I
modifications to 25 tons when aggregated with all other net increases in emissions at the
source over the five years preceding the change. For these areas, there is a cumulative limit
of 25 tons that, if exceeded, would trigger a Title I modification and would prevent the
source from using the minor permit modification procedures for changes above these limits.
In other nonattainment areas and in attainment areas, certain increases above prescribed
significance levels would also be aggregated with all other net increases in emissions at the
source within a five-year contemporaneous period.
Prevention of Significant Deterioration. The definition of modification for the PSD program
is similar to the NSR definition and is contained in part C of the Act and in part 51. A
modification is subject to PSD review only if the existing source that is modified is "major,"
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and the net emissions increase of any pollutant emitted by the source as a result of the
modification is greater than established significance levels. Also, sources located within
10 kilometers of a Class I area that will cause an increase of 1 microgram per cubic meter
(24 hour average) or more in the ambient concentration of a regulated pollutant is significant.
National Emission Standards for Hazardous Air Pollutants. The modification provisions of
the NESHAP program are based on the following definition of modification from §112(a)(5)
of the Act:
"... any physical change in, or change in the method of operation of, a major source
which increases the actual emissions of any hazardous air pollutant emitted by such
source by more than a de minimis amount or which results in the emission of any
hazardous air pollutant not previously emitted by more than a de minimis amount."
The EPA is establishing de minimis quantities of HAPs and allowing sources to offset more
toxic HAP emissions with less toxic HAP emissions.
The modification provisions of the NESHAP program under part 61 (pre-1990
amendments) are based on the following definition of modification from §61.15:
"... any physical or operational change to a stationary source which results in an
increase in the rate of emission to the atmosphere of a hazardous pollutant to which a
standard applies ..."
Section 61.15(d) lists the following exceptions to this definition:
1. Maintenance, repair, and replacement which the Administrator determines to be
routine for a source category;
2. An increase in production rate of a stationary source, if that increase can be
accomplished without a capital expenditure on the stationary source;
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3. An increase in the hours of operation;
4. Any conversion to coal that meets the requirements specifies in §lll(a)(8) of the
Act; and
5. The relocation or change in ownership of a stationary source.
State Preconstruction Review Programs. Section 110(a)(2)(C) of the Act requires that each
SIP contain regulations for modification and construction of any stationary source within the
areas covered by the plan as necessary to assure that national ambient air quality standards
are achieved. Therefore, an individual SIP may contain a more stringent definition of
modification than other Title I definitions.
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