be $48.0 million and the total annualized costs to be about $10.3
million in 2016 dollars (annualized costs include annual recovery
credits of $290,000). The present value in 2016 of the costs is $87.2
million at a discount rate of 3 percent and $ 71.8 million at 7
percent. Calculated as an equivalent annualized value, which is
consistent with the present value of costs in 2016, the costs are $12.0
million at a discount rate of 7 percent and $12.4 million at a discount
rate of 3 percent. The costs are associated with the proposed
amendments for flares, pressure relief devices, maintenance (equipment
openings), storage vessels, heat exchange systems, and decoking
operations for ethylene cracking furnaces. Costs for flares include
purchasing analyzers, monitors, natural gas and steam, developing a
flare management plan, and performing root cause analysis and
corrective action (details are available in section IV.A.1.h of this
preamble and the memorandum titled Control Option Impacts for Flares
Located in the Ethylene Production Source Category, in Docket ID No.
EPA-HQ-OAR-2017-0357). Costs for pressure relief devices were developed
based on compliance with the proposed work practice standard and
include implementation of three prevention measures, performing root
cause analysis and corrective action, and purchasing pressure relief
device monitors (details are available in section IV.A.2.a of this
preamble and the memorandum titled Review of Regulatory Alternatives
for Certain Vent Streams in the Ethylene Production Source Category, in
Docket ID No. EPA-HQ-OAR-2017-0357). Maintenance costs were estimated
to document equipment opening procedures and to document circumstances
under which the alternative maintenance vent limit is used (details are
available in section IV.A.2.d of this preamble and the memorandum
titled Review of Regulatory Alternatives for Certain Vent Streams in
the Ethylene Production Source Category, in Docket ID No. EPA-HQ-OAR-
2017-0357). Costs for storage vessels include installing IFRs and
upgrading deck fittings (details are available in section IV.D.1 of
this preamble and the memorandum titled Clean Air Act Section 112(d)(6)
Technology Review for Storage Vessels Located in the Ethylene
Production Source Category, in Docket ID No. EPA-HQ-OAR-2017-0357).
Heat exchange systems costs include the use of the Modified El Paso
Method to monitor for leaks (details are available in section IV.D.6 of
this preamble and the memorandum titled Clean Air Act Section 112(d)(6)
Technology Review for Heat Exchange Systems in the Ethylene Production
Source Category, in Docket ID No. EPA-HQ-OAR-2017-0357). The costs
associated with decoking operations for ethylene cracking furnaces
include conducting isolation valve inspections and conducting flame
impingement firebox inspections (details are available in section
IV.A.3 of this preamble and the memorandum titled Assessment of Work
Practice Standards for Ethylene Cracking Furnace Decoking Operations
Located in the Ethylene Production Source Category, in Docket ID No.
EPA-HQ-OAR-2017-0357).

D. What are the economic impacts?

    The EPA conducted economic impact analyses for this proposal, as
detailed in

the memorandum titled Economic Impact Analysis for the Proposed
Ethylene Production Risk and Technology Review (RTR) NESHAP, which is
available in the docket for this action. The economic impacts of the
proposal are calculated as the percentage of total annualized costs
incurred by affected parent owners to their annual revenues. This ratio
of total annualized costs to annual revenues provides a measure of the
direct economic impact to parent owners of ethylene production
facilities while presuming no passthrough of costs to ethylene
consumers. We estimate that none of the 16 parent owners affected by
this proposal will incur total annualized costs of 0.02 percent or
greater of their revenues. Product recovery, which is estimated as an
impact of the proposed rule, is included in the estimate of total
annualized costs that is an input to the economic impact analysis.
Thus, these economic impacts are quite low for affected companies and
the ethylene production industry, and consumers of ethylene should
experience minimal price changes.

VI. Request for Comments

    We solicit comments on this proposed action. In addition to general
comments on this proposed action, we are also interested in additional
data that may improve the risk assessments and other analyses. We are
specifically interested in receiving any improvements to the data used
in the site-specific emissions profiles used for risk modeling. Such
data should include supporting documentation in sufficient detail to
allow characterization of the quality and representativeness of the
data or information. Section VII of this preamble provides more
information on submitting data.

VII. Submitting Data Corrections

    The site-specific emissions profiles used in the source category
risk and demographic analyses and instructions are available for
download on the RTR website at https://www3.epa.gov/ttn/atw/rrisk/rtrpg.html. The data files include detailed information for each HAP
emissions release point for the facilities in the source category.
    If you believe that the data are not representative or are
inaccurate, please identify the data in question, provide your reason
for concern, and provide any ``improved'' data that you have, if
available. When you submit data, we request that you provide
documentation of the basis for the revised values to support your
suggested changes. To submit comments on the data downloaded from the
RTR website, complete the following steps:
    1. Within this downloaded file, enter suggested revisions to the
data fields appropriate for that information.
    2. Fill in the commenter information fields for each suggested
revision (i.e., commenter name, commenter organization, commenter email
address, commenter phone number, and revision comments).
    3. Gather documentation for any suggested emissions revisions
(e.g., performance test reports, material balance calculations).
    4. Send the entire downloaded file with suggested revisions in
Microsoft[supreg] Access format and all accompanying documentation to
Docket ID No. EPA-HQ-OAR-2017-0357 (through the method described in the
ADDRESSES section of this preamble).
    5. If you are providing comments on a single facility or multiple
facilities, you need only submit one file for all facilities. The file
should contain all suggested changes for all sources at that facility
(or facilities). We request that all data revision comments be
submitted in the form of updated Microsoft[supreg] Excel files that are
generated by the Microsoft[supreg] Access file. These files are
provided on the RTR website at https://www3.epa.gov/ttn/atw/rrisk/rtrpg.html.

VIII. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders
can be found at https://www.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 13563: Improving Regulation and Regulatory Review

    This action is a significant regulatory action that was submitted
to OMB for review because it raises novel legal or policy issues. Any
changes made in response to OMB recommendations have been documented in
the docket. The EPA prepared an analysis of the potential costs and
benefits associated with this action. This analysis, Economic Impact
Analysis for the Proposed Ethylene Production Risk and Technology
Review (RTR) NESHAP, is available in the docket for this rule.

B. Executive Order 13771: Reducing Regulations and Controlling
Regulatory Costs

    This action is expected to be an Executive Order 13771 regulatory
action. Details on the estimated costs of this proposed rule can be
found in section V of this preamble.

C. Paperwork Reduction Act (PRA)

    The information collection activities in this proposed rule have
been submitted for approval to OMB under the PRA. The Information
Collection Request (ICR) document that the EPA prepared has been
assigned EPA ICR number 1983.09. You can find a copy of the ICR in the
docket for this rule, and it is briefly summarized here.
    We are proposing amendments that change the reporting and
recordkeeping requirements for several emission sources at ethylene
production facilities (e.g., flares, decoking operations for ethylene
cracking furnaces, heat exchangers, PRDs, storage vessels). The
proposed amendments also require electronic reporting, remove the
malfunction exemption, and impose other revisions that affect reporting
and recordkeeping. This information would be collected to assure
compliance with 40 CFR part 63, subparts XX and YY.
    Respondents/affected entities: Owners or operators of ethylene
production facilities.
    Respondent's obligation to respond: Mandatory (40 CFR part 63,
subparts XX and YY).
    Estimated number of respondents: 31 facilities.
    Frequency of response: Semiannual or annual. Responses include
performance evaluation notifications and reports, NOCS, and semiannual
compliance reports.
    Total estimated burden: 8,500 hours (per year). Burden is defined
at 5 CFR 1320.3(b).
    Total estimated cost: $4,410,000 (per year), which includes
$3,660,000 annualized capital and operation and maintenance costs for
the responding facilities.
    An agency may not conduct or sponsor, and a person is not required
to respond to, a collection of information unless it displays a
currently valid OMB control number. The OMB control numbers for the
EPA's regulations in 40 CFR are listed in 40 CFR part 9.
    Submit your comments on the Agency's need for this information, the
accuracy of the provided burden estimates, and any suggested methods
for minimizing respondent burden to the EPA using the docket identified
at the beginning of this rule. You may also send your ICR-related
comments to OMB's Office of Information and Regulatory Affairs via
email to<EMAIL_ADDRESS>Attention: Desk Officer for EPA.
Because OMB is required to make a decision concerning the ICR between
30 and 60 days after receipt, OMB must receive comments no later than
November 8, 2019. The EPA

will respond to any ICR-related comments in the final rule.

D. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic
impact on a substantial number of small entities under the RFA as
amended by the Small Business Regulatory Enforcement Fairness Act
(SBREFA). This action will not impose any requirements on small
entities. This action is projected to affect 31 facilities, and none of
these facilities is owned by a small entity. Details of the associated
analysis are presented in the memorandum, Economic Impact Analysis for
the Proposed Ethylene Production Risk and Technology Review (RTR)
NESHAP, which is available in the docket for this action.

E. Unfunded Mandates Reform Act (UMRA)

    This action does not contain an unfunded mandate of $100 million or
more as described in UMRA, 2 U.S.C. 1531-1538, and does not
significantly or uniquely affect small governments. The action imposes
no enforceable duty on any state, local, or tribal governments.

F. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have
substantial direct effects on the states, on the relationship between
the national government and the states, or on the distribution of power
and responsibilities among the various levels of government.

G. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments

    This action does not have tribal implications as specified in
Executive Order 13175. None of the ethylene production facilities that
have been identified as being affected by this action are owned or
operated by tribal governments or located within tribal lands. Thus,
Executive Order 13175 does not apply to this action.

H. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks

    This action is not subject to Executive Order 13045 because it is
not economically significant as defined in Executive Order 12866, and
because the EPA does not believe the environmental health or safety
risks addressed by this action present a disproportionate risk to
children. This action's health and risk assessments are contained in
sections III.A and C and sections IV.B and C of this preamble.

I. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use

    This action is not a ``significant energy action'' because it is
not likely to have a significant adverse effect on the supply,
distribution, or use of energy. The overall economic impact of this
proposed rule should be minimal for ethylene production facilities and
their parent companies (which are engaged in the energy sector).

J. National Technology Transfer and Advancement Act (NTTAA) and 1 CFR
Part 51

    This action involves technical standards. Therefore, the EPA
conducted searches for the Ethylene Production NESHAP through the
Enhanced National Standards Systems Network (NSSN) Database managed by
the American National Standards Institute (ANSI). We also contacted
voluntary consensus standards (VCS) organizations and accessed and
searched their databases. We conducted searches for EPA Methods 1, 1A,
2, 2A, 2C, 2D, 2F, 2G, 3B, 4, 5, 18, 21, 22, 25, 25A, 27, and 29 of 40
CFR part 60, appendix A, 301, 316, and 320 of 40 CFR part 63, appendix
A, and 602 and 624 of 40 CFR part 136, appendix A. During the EPA's VCS
search, if the title or abstract (if provided) of the VCS described
technical sampling and analytical procedures that are similar to the
EPA's reference method, the EPA ordered a copy of the standard and
reviewed it as a potential equivalent method. We reviewed all potential
standards to determine the practicality of the VCS for this rule. This
review requires significant method validation data that meet the
requirements of EPA Method 301 for accepting alternative methods or
scientific, engineering, and policy equivalence to procedures in the
EPA reference methods. The EPA may reconsider determinations of
impracticality when additional information is available for particular
VCS.
    No applicable voluntary consensus standards were identified for EPA
Methods 1A, 2A, 2D, 2F, 2G, 21, 22, 27, 316, 602, and 624. The
following VCS were identified as acceptable alternatives to the EPA
test methods for the purpose of this rule.
    The EPA proposes to use the VCS ANSI/ASME PTC 19-10-1981--Part 10,
``Flue and Exhaust Gas Analyses'' as an acceptable alternative to EPA
Methods 3A and 3B for the manual procedures only and not the
instrumental procedures. The ANSI/ASME PTC 19-10-1981--Part 10 method
incorporates both manual and instrumental methodologies for the
determination of oxygen content. The manual method segment of the
oxygen determination is performed through the absorption of oxygen.
This method is available at the American National Standards Institute
(ANSI), 1899 L Street NW, 11th Floor, Washington, DC 20036 and the
American Society of Mechanical Engineers (ASME), Three Park Avenue, New
York, NY 10016-5990. See https://wwww.ansi.org and https://www.asme.org.
    Also, the EPA proposes to use the VCS ASTM D6420-18, ``Standard
Test Method for Determination of Gaseous Organic Compounds by Direct
Interface Gas Chromatography-Mass Spectrometry'' as an acceptable
alternative to EPA Method 18 with the following caveats. This ASTM
procedure has been approved by the EPA as an alternative to EPA Method
18 only when the target compounds are all known and the target
compounds are all listed in ASTM D6420 as measurable. We are proposing
that ASTM D6420-18 should not be used for methane and ethane because
the atomic mass is less than 35; and ASTM D6420 should never be
specified as a total VOC method. The ASTM D6420-18 test method employs
a direct interface gas chromatograph/mass spectrometer to measure 36
VOC. The test method provides on-site analysis of extracted,
unconditioned, and unsaturated (at the instrument) gas samples from
stationary sources.
    In addition, the EPA proposes to use the VCS ASTM D6348-12e1,
``Determination of Gaseous Compounds by Extractive Direct Interface
Fourier Transform (FTIR) Spectroscopy'' as an acceptable alternative to
EPA Method 320 with caveats requiring inclusion of selected annexes to
the standard as mandatory. The ASTM D6348-12e1 method is an extractive
FTIR Spectroscopy-based field test method and is used to quantify gas
phase concentrations of multiple target compounds in emission streams
from stationary sources. We are proposing the test plan preparation and
implementation in the Annexes to ASTM D 6348-03, Sections Al through A8
are mandatory; and in ASTM D6348-03 Annex A5 (Analyte Spiking
Technique), the percent (%) R must be determined for each target
analyte (Equation A5.5). We are proposing that in order for the test
data to be acceptable for a compound, %R must be 70% >= R <= 130%. If
the %R value does not meet this criterion for a target compound, the
test data is not acceptable for that compound and the test must be
repeated

for that analyte (i.e., the sampling and/or analytical procedure should
be adjusted before a retest). We are proposing that the %R value for
each compound must be reported in the test report, and all field
measurements must be corrected with the calculated %R value for that
compound by using the following equation:

Reported Results = (Measured Concentration in the Stack x 100)/% R.

    The two ASTM methods (ASTM D6420-18 and ASTM D6348-12e1) are
available at ASTM International, 1850 M Street NW, Suite 1030,
Washington, DC 20036. See https://www.astm.org/.
    The search identified 17 other VCS that were potentially applicable
for this rule in lieu of the EPA reference methods. After reviewing the
available standards, the EPA determined that 17 candidate VCS
identified for measuring emissions of pollutants or their surrogates
subject to emission standards in the rule would not be practical due to
lack of equivalency, documentation, validation data and other important
technical and policy considerations. Additional information for the VCS
search and determinations can be found in the memorandum, Voluntary
Consensus Standard Results for National Emission Standards for
Hazardous Air Pollutants for Ethylene Production RTR, which is
available in the docket for this action.
    Finally, we are proposing at 40 CFR 63.1107(a) to incorporate by
reference SW-846-8260B, Volatile Organic Compounds by Gas
Chromatography/Mass Spectrometry (GC/MS), Revision 2, December 1996, in
EPA Publication No. SW-846, Test Methods for Evaluating Solid Waste,
Physical/Chemical Methods, Third Edition; and SW-846-8270D,
Semivolatile Organic Compounds by Gas Chromatography/Mass Spectrometry
(GC/MS), Revision 4, February 2007, in EPA Publication No. SW-846, Test
Methods for Evaluating Solid Waste, Physical/Chemical Methods, Third
Edition. Method SW-846-8260B is used to determine VOC in a variety of
solid waste matrices with gas chromatography/mass spectrometry. Method
SW-846-8260 can be used to quantitate most VOC that have boiling points
below 200 degrees Celsius, including low molecular weight halogenated
hydrocarbons, aromatics, ketones, nitriles, acetates, acrylates,
ethers, and sulfides. Method SW-846-8270D is used to determine the
concentration of semivolatile organic compounds in a variety of solid
waste matrices with gas chromatography/mass spectrometry. Method SW-
846-8270D can be used to quantitate semivolatile compounds such as
polyaromatic hydrocarbons, chlorinated hydrocarbons, pesticides,
phthalate esters, organophosphate esters, nitrosamines, haloethers,
aldehydes, ethers, ketones, anilines, pyridines, quinolines, aromatic
nitro compounds, and phenols, including nitrophenols. The two SW-846
methods (Method SW-846-8260B and Method SW-846-8270D) are available in
the docket for this rulemaking and on EPA's website. See https://www.epa.gov/hw-sw846.
    The EPA welcomes comments on this aspect of the proposed rulemaking
given that these proposed changes are being made in 40 CFR part 63,
subpart SS, and, specifically, invites the public to identify
potentially applicable VCS, and to explain why the EPA should use such
standards in this regulation.

K. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations

    The EPA believes that this action does not have disproportionately
high and adverse human health or environmental effects on minority
populations, low-income populations, and/or indigenous peoples, as
specified in Executive Order 12898 (58 FR 7629, February 16, 1994). Our
analysis of the demographics of the population with estimated risks
greater than 1-in-1 million indicates potential disparities in risks
between demographic groups, including the African American, Hispanic or
Latino, Over 25 Without a High School Diploma, and Below the Poverty
Level groups. In addition, the population living within 50 km of the
ethylene production facilities has a higher percentage of minority,
lower income, and lower education people when compared to the
nationwide percentages of those groups. However, acknowledging these
potential disparities, the risks for the source category were
determined to be acceptable, and emissions reductions from the proposed
revisions will benefit these groups the most.
    The documentation for this decision is contained in section IV.B
and C of this preamble, and the technical report, Risk and Technology
Review--Analysis of Demographic Factors for Populations Living Near
Ethylene Production Source Category Operations, which is available in
the docket for this action.

List of Subjects in 40 CFR Part 63

    Environmental protection, Air pollution control, Hazardous
substances, Incorporation by reference, Reporting and recordkeeping
requirements.

    Dated: September 5, 2019.
Andrew R. Wheeler,
Administrator.

    For the reasons set forth in the preamble, the EPA proposes to
amend 40 CFR part 63 as follows:

PART 63--NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS
FOR SOURCE CATEGORIES

0
1. The authority citation for part 63 continues to read as follows:

    Authority:  42 U.S.C. 7401 et seq.

Subpart A--[Amended]

0
2. Section 63.14 is amended by:
0
a. Revising paragraphs (e)(1) and (h)(18) and (85);
0
b. Redesignating paragraphs (h)(92) through (111) as paragraphs (h)(93)
through (112);
0
c. Adding new paragraph (h)(92);
0
d. Revising paragraphs (n)(12) and (13); and
0
e. Revising paragraph (t)(1).
    The revisions and addition read as follows:

Sec.  63.14   Incorporations by reference.

* * * * *
    (e) * * *
    (1) ANSI/ASME PTC 19.10-1981, Flue and Exhaust Gas Analyses [Part
10, Instruments and Apparatus], issued August 31, 1981, IBR approved
for Sec. Sec.  63.309(k), 63.457(k), 63.772(e) and (h), 63.865(b),
63.997(e), 63.1282(d) and (g), 63.1625(b), 63.3166(a), 63.3360(e),
63.3545(a), 63.3555(a), 63.4166(a), 63.4362(a), 63.4766(a), 63.4965(a),
63.5160(d), table 4 to subpart UUUU, 63.9307(c), 63.9323(a),
63.11148(e), 63.11155(e), 63.11162(f), 63.11163(g), 63.11410(j),
63.11551(a), 63.11646(a), and 63.11945, table 5 to subpart DDDDD, table
4 to subpart JJJJJ, table 4 to subpart KKKKK, tables 4 and 5 of subpart
UUUUU, table 1 to subpart ZZZZZ, and table 4 to subpart JJJJJJ.
* * * * *
    (h) * * *
    (18) ASTM D1946-90 (Reapproved 1994), Standard Method for Analysis
of Reformed Gas by Gas Chromatography, IBR approved for Sec. Sec.
63.11(b), 63.987(b), and 63.1412.
* * * * *
    (85) ASTM D6348-12e1, Standard Test Method for Determination of
Gaseous Compounds by Extractive Direct Interface Fourier Transform
Infrared (FTIR) Spectroscopy, Approved

February 1, 2012, IBR approved for Sec. Sec.  63.997(e) and 63.1571(a).
* * * * *
    (92) ASTM D6420-18, Standard Test Method for Determination of
Gaseous Organic Compounds by Direct Interface Gas Chromatography-Mass
Spectrometry, IBR approved for Sec.  63.987(b) and Sec.  63.997(e).
* * * * *
    (n) * * *
    (12) SW-846-8260B, Volatile Organic Compounds by Gas
Chromatography/Mass Spectrometry (GC/MS), Revision 2, December 1996, in
EPA Publication No. SW-846, Test Methods for Evaluating Solid Waste,
Physical/Chemical Methods, Third Edition, IBR approved for Sec. Sec.
63.1107(a), 63.11960, 63.11980, and table 10 to subpart HHHHHHH.
    (13) SW-846-8270D, Semivolatile Organic Compounds by Gas
Chromatography/Mass Spectrometry (GC/MS), Revision 4, February 2007, in
EPA Publication No. SW-846, Test Methods for Evaluating Solid Waste,
Physical/Chemical Methods, Third Edition, IBR approved for Sec. Sec.
63.1107(a), 63.11960, 63.11980, and table 10 to subpart HHHHHHH.
* * * * *
    (t) * * *
    (1) ``Air Stripping Method (Modified El Paso Method) for
Determination of Volatile Organic Compound Emissions from Water
Sources,'' Revision Number One, dated January 2003, Sampling Procedures
Manual, Appendix P: Cooling Tower Monitoring, January 31, 2003, IBR
approved for Sec. Sec.  63.654(c) and (g), 63.655(i), 63.1086(e),
63.1089(d), and 63.11920.
* * * * *

Subpart SS--[Amended]

0
3. Section 63.987 is amended by revising parameter ``Dj'' of Equation 1
in paragraph (b)(3)(ii) to read as follows:

Sec.  63.987   Flare requirements.

* * * * *
    (b) * * *
    (3) * * *
    (ii) * * *
* * * * *
    Dj = Concentration of sample component j, in parts per million by
volume on a wet basis, as measured for organics by Method 18 of 40 CFR
part 60, appendix A, or by American Society for Testing and Materials
(ASTM) D6420-18 (Incorporated by reference in Sec.  63.14)) under the
conditions specified in Sec.  63.997(e)(2)(iii)(D)(1) through (3).
Hydrogen and carbon monoxide are measured by ASTM D1946-90
(Incorporated by reference, see Sec.  63.14); and
* * * * *
0
4. Section 63.997 is amended by revising paragraphs (e)(2)(iii)
introductory text, (e)(2)(iii)(C)(1), (e)(2)(iii)(D), (e)(2)(iv)
introductory text, (e)(2)(iv)(F) and (I) to read as follows:

Sec.  63.997   Performance test and compliance assessment requirements
for control devices.

* * * * *
    (e) * * *
    (2) * * *
    (iii) To determine compliance with a parts per million by volume
total organic regulated material or TOC limit, the owner or operator
shall use Method 18 or 25A of 40 CFR part 60, appendix A, as
applicable. The ASTM D6420-18 (Incorporated by reference, see Sec.
63.14) may be used in lieu of Method 18 of 40 CFR part 60, appendix A,
under the conditions specified in paragraphs (e)(2)(iii)(D)(1) through
(3) of this section. Alternatively, any other method or data that have
been validated according to the applicable procedures in Method 301 of
appendix A of 40 CFR part 63 may be used. The procedures specified in
paragraphs (e)(2)(iii)(A), (B), (D), and (E) of this section shall be
used to calculate parts per million by volume concentration. The
calculated concentration shall be corrected to 3 percent oxygen using
the procedures specified in paragraph (e)(2)(iii)(C) of this section if
a combustion device is the control device and supplemental combustion
air is used to combust the emissions.
* * * * *
    (C) * * *
    (1) The emission rate correction factor (or excess air), integrated
sampling and analysis procedures of Method 3B of 40 CFR part 60,
appendix A, or the manual method in ANSI/ASME PTC 19-10-1981--Part 10
(Incorporated by reference, see Sec.  63.14)), shall be used to
determine the oxygen concentration. The sampling site shall be the same
as that of the organic regulated material or organic compound samples,
and the samples shall be taken during the same time that the organic
regulated material or organic compound samples are taken.
* * * * *
    (D) To measure the total organic regulated material concentration
at the outlet of a control device, use Method 18 of 40 CFR part 60,
appendix A, or ASTM D6420-18. If you have a combustion control device,
you must first determine which regulated material compounds are present
in the inlet gas stream using process knowledge or the screening
procedure described in Method 18. In conducting the performance test,
analyze samples collected at the outlet of the combustion control
device as specified in Method 18 or ASTM D6420-18 for the regulated
material compounds present at the inlet of the control device. The
method ASTM D6420-18 may be used only under the conditions specified in
paragraphs (e)(2)(iii)(D)(1) through (3) of this section.
    (1) If the target compounds are all known and are all listed in
Section 1.1 of ASTM D6420-18 as measurable.
    (2) ASTM D6420-18 may not be used for methane and ethane.
    (3) ASTM D6420-18 may not be used as a total VOC method.
* * * * *
    (iv) Percent reduction calculation. To determine compliance with a
percent reduction requirement, the owner or operator shall use Method
18, 25, or 25A of 40 CFR part 60, appendix A, as applicable. The method
ASTM D6420-18 may be used in lieu of Method 18 of 40 CFR part 60,
appendix A, under the conditions specified in paragraphs
(e)(2)(iii)(D)(1) through (3) of this section. Alternatively, any other
method or data that have been validated according to the applicable
procedures in Method 301 of appendix A of 40 CFR part 63 may be used.
The procedures specified in paragraphs (e)(2)(iv)(A) through (I) of
this section shall be used to calculate percent reduction efficiency.
* * * * *
    (F) To measure inlet and outlet concentrations of total organic
regulated material, use Method 18 of 40 CFR part 60, appendix A, or
ASTM D6420-18, under the conditions specified in paragraphs
(e)(2)(iii)(D)(1) through (3) of this section. In conducting the
performance test, collect and analyze samples as specified in Method 18
or ASTM D6420-18. You must collect samples simultaneously at the inlet
and outlet of the control device. If the performance test is for a
combustion control device, you must first determine which regulated
material compounds are present in the inlet gas stream (i.e.,
uncontrolled emissions) using process knowledge or the screening
procedure described in Method 18. Quantify the emissions for the
regulated material compounds present in the inlet gas stream for both
the inlet and outlet gas streams for the combustion device.
* * * * *
    (I) If the uncontrolled or inlet gas stream to the control device
contains formaldehyde, you must conduct emissions testing according to

paragraphs (e)(2)(iv)(I)(1) through (3) of this section.
    (1) Except as specified in paragraph (e)(2)(iv)(I)(3) of this
section, if you elect to comply with a percent reduction requirement
and formaldehyde is the principal regulated material compound (i.e.,
greater than 50 percent of the regulated material compounds in the
stream by volume), you must use Method 316 or 320 of 40 CFR part 63,
appendix A, to measure formaldehyde at the inlet and outlet of the
control device. Use the percent reduction in formaldehyde as a
surrogate for the percent reduction in total regulated material
emissions.
    (2) Except as specified in paragraph (e)(2)(iv)(I)(3) of this
section, if you elect to comply with an outlet total organic regulated
material concentration or TOC concentration limit, and the uncontrolled
or inlet gas stream to the control device contains greater than 10
percent (by volume) formaldehyde, you must use Method 316 or 320 of 40
CFR part 63, appendix A, to separately determine the formaldehyde
concentration. Calculate the total organic regulated material
concentration or TOC concentration by totaling the formaldehyde
emissions measured using Method 316 or 320 and the other regulated
material compound emissions measured using Method 18 or 25/25A.
    (3) You may elect to use ASTM D6348-12e1 (Incorporated by
reference, Sec.  63.14) in lieu of Method 316 or 320 of 40 CFR part 63,
appendix A as specified in paragraph (e)(2)(iv)(I)(1) or (2) of this
section. To comply with this paragraph, the test plan preparation and
implementation in the Annexes to ASTM D 6348-03 (Incorporated by
reference, see Sec.  63.14) Sections A1 through A8 are mandatory; the
percent (%) R must be determined for each target analyte using Equation
A5.5 of ASTM D6348-03 Annex A5 (Analyte Spiking Technique); and in
order for the test data to be acceptable for a compound, the %R must be
70% >= R <= 130%. If the %R value does not meet this criterion for a
target compound, then the test data is not acceptable for that compound
and the test must be repeated for that analyte (i.e., the sampling and/
or analytical procedure should be adjusted before a retest). The %R
value for each compound must be reported in the test report, and all
field measurements must be corrected with the calculated %R value for
that compound by using the following equation:
    Reported Results = (Measured Concentration in the Stack x 100)/%R.

Subpart XX--[Amended]

0
5. Section 63.1081 is revised to read as follows:

Sec.  63.1081   When must I comply with the requirements of this
subpart?

    Except as specified in paragraphs (a) and (b) of this section, you
must comply with the requirements of this subpart according to the
schedule specified in Sec.  63.1102(a).
    (a) Each heat exchange system at an ethylene production affected
source that commenced construction or reconstruction on or before
October 9, 2019, must be in compliance with the heat exchange system
requirements specified in Sec.  63.1084(f), Sec.  63.1085(e) and (f),
Sec.  63.1086(e), Sec.  63.1087(c) and (d), Sec.  63.1088(d), and Sec.
63.1089(d) and (e) upon initial startup or [date 3 years after date of
publication of final rule in the Federal Register], whichever is later.
Each heat exchange system at an ethylene production affected source
that commences construction or reconstruction after October 9, 2019,
must be in compliance with the heat exchange system requirements
specified in Sec. Sec.  63.1084(f), 63.1085(e) and (f), 63.1086(e),
63.1087(c) and (d), 63.1088(d), and 63.1089(d) and (e) upon initial
startup, or [date of publication of final rule in the Federal
Register], whichever is later.
    (b) Each waste stream at an ethylene production affected source
that commenced construction or reconstruction on or before October 9,
2019, must be in compliance with the flare requirements specified in
Sec.  63.1095(a)(1)(vi) and (b)(3) upon initial startup or [date 3
years after date of publication of final rule in the Federal Register],
whichever is later. Each waste stream at an ethylene production
affected source that commences construction or reconstruction after
October 9, 2019, must be in compliance with the flare requirements
specified in Sec.  63.1095(a)(1)(vi) and (b)(3) upon initial startup,
or [date of publication of final rule in the Federal Register],
whichever is later.
0
6. Section 63.1082 is amended by revising definitions for ``Dilution
steam blowdown waste stream,'' and ``Spent caustic waste stream'' to
read as follows:

Sec.  63.1082   What definitions do I need to know?

* * * * *
    Dilution steam blowdown waste stream means any continuously flowing
process wastewater stream resulting from the quench and compression of
cracked gas (the cracking furnace effluent) at an ethylene production
unit and is discharged from the unit. This stream typically includes
the aqueous or oily-water stream that results from condensation of
dilution steam (in the cracking furnace quench system), blowdown from
dilution steam generation systems, and aqueous streams separated from
the process between the cracking furnace and the cracked gas
dehydrators. Before [date 3 years after date of publication of final
rule in the Federal Register], the dilution steam blowdown waste stream
does not include dilution steam blowdown streams generated from
sampling, maintenance activities, or shutdown purges. Beginning on
[date 3 years after date of publication of final rule in the Federal
Register], the dilution steam blowdown streams generated from sampling,
maintenance activities, or shutdown purges are included in the
definition of dilution steam blowdown waste stream. The dilution steam
blowdown waste stream also does not include blowdown that has not
contacted HAP-containing process materials.
* * * * *
    Spent caustic waste stream means the continuously flowing process
wastewater stream that results from the use of a caustic wash system in
an ethylene production unit. A caustic wash system is commonly used at
ethylene production units to remove acid gases and sulfur compounds
from process streams, typically cracked gas. Before [date 3 years after
date of publication of final rule in the Federal Register], the spent
caustic waste stream does not include spent caustic streams generated
from sampling, maintenance activities, or shutdown purges. Beginning on
[date 3 years after date of publication of final rule in the Federal
Register], the spent caustic streams generated from sampling,
maintenance activities, or shutdown purges are included in the
definition of spent caustic waste stream.
* * * * *
0
7. Section 63.1084 is amended by revising the introductory text and
adding paragraph (f) to read as follows:

Sec.  63.1084   What heat exchange systems are exempt from the
requirements of this subpart?

    Except as specified in paragraph (f) of this section, your heat
exchange system is exempt from the requirements in Sec. Sec.  63.1085
and 63.1086 if it meets any one of the criteria in paragraphs (a)
through (e) of this section.
* * * * *
    (f) Beginning no later than the compliance dates specified in

Sec.  63.1081(a), your heat exchange system is no longer exempt from
the requirements in Sec. Sec.  63.1085 and 63.1086 if it meets the
criteria in paragraphs (c) or (d) of this section; instead, your heat
exchange system is exempt from the requirements in Sec. Sec.  63.1085
and 63.1086 if it meets any one of the criteria in paragraphs (a), (b),
or (e) of this section.
0
8. Section 63.1085 is amended by revising the introductory text and
paragraphs (a) and (b), and by adding paragraphs (e) and (f) to read as
follows:

Sec.  63.1085   What are the general requirements for heat exchange
systems?

    Unless you meet one of the requirements for exemptions in Sec.
63.1084, you must meet the requirements in paragraphs (a) through (f)
of this section.
    (a) Except as specified in paragraph (e) of this section, you must
monitor the cooling water for the presence of substances that indicate
a leak according to Sec.  63.1086(a) through (d).
    (b) Except as specified in paragraph (f) of this section, if you
detect a leak, then you must repair it according to Sec.  63.1087(a)
and (b) unless repair is delayed according to Sec.  63.1088(a) through
(c).
* * * * *
    (e) Beginning no later than the compliance dates specified in Sec.
63.1081(a), the requirements specified in Sec.  63.1086(a) through (d)
no longer apply; instead, you must monitor the cooling water for the
presence of total strippable hydrocarbon concentration (as methane)
that indicate a leak according to Sec.  63.1086(e). At any time before
the compliance dates specified in Sec.  63.1081(a), you may choose to
comply with the requirements in this paragraph in lieu of the
requirements in paragraph (a) of this section.
    (f) Beginning no later than the compliance dates specified in Sec.
63.1081(a), the requirements specified in Sec.  63.1087(a) and (b), and
Sec.  63.1088(a) through (c), no longer apply; instead, if you detect a
leak, then you must repair it according to Sec.  63.1087(c) and (d),
unless repair is delayed according to Sec.  63.1088(d). At any time
before the compliance dates specified in Sec.  63.1081(a), you may
choose to comply with the requirements in this paragraph in lieu of the
requirements in paragraph (b) of this section.
0
9. Section 63.1086 is amended by revising the introductory text and by
adding paragraph (e) to read as follows:

Sec.  63.1086   How must I monitor for leaks to cooling water?

    Except as specified in Sec.  63.1085(e) and paragraph (e) of this
section, you must monitor for leaks to cooling water by monitoring each
heat exchange system according to the requirements of paragraph (a) of
this section, monitoring each heat exchanger according to the
requirements of paragraph (b) of this section, or monitoring a
surrogate parameter according to the requirements of paragraph (c) of
this section. Except as specified in Sec.  63.1085(e) and paragraph (e)
of this section, if you elect to comply with the requirements of
paragraph (a) or (b) of this section, you may use alternatives in
paragraph (d)(1) or (2) of this section for determining the mean
entrance concentration.
* * * * *
    (e) Beginning no later than the compliance dates specified in Sec.
63.1081(a), you must perform monitoring to identify leaks of total
strippable hydrocarbon concentration (as methane) from each heat
exchange system subject to the requirements of this subpart according
to the procedures in paragraphs (e)(1) through (5) of this section.
    (1) Monitoring locations for closed-loop recirculation heat
exchange systems. For each closed loop recirculating heat exchange
system, you must collect and analyze a sample from the location(s)
described in either paragraph (e)(1)(i) or (ii) of this section.
    (i) Each cooling tower return line or any representative riser
within the cooling tower prior to exposure to air for each heat
exchange system.
    (ii) Selected heat exchanger exit line(s), so that each heat
exchanger or group of heat exchangers within a heat exchange system is
covered by the selected monitoring location(s).
    (2) Monitoring locations for once-through heat exchange systems.
For each once-through heat exchange system, you must collect and
analyze a sample from the location(s) described in paragraph (e)(2)(i)
of this section. You may also elect to collect and analyze an
additional sample from the location(s) described in paragraph
(e)(2)(ii) of this section.
    (i) Selected heat exchanger exit line(s), so that each heat
exchanger or group of heat exchangers within a heat exchange system is
covered by the selected monitoring location(s). The selected monitoring
location may be at a point where discharges from multiple heat exchange
systems are combined provided that the combined cooling water flow rate
at the monitoring location does not exceed 40,000 gallons per minute.
    (ii) The inlet water feed line for a once-through heat exchange
system prior to any heat exchanger. If multiple heat exchange systems
use the same water feed (i.e., inlet water from the same primary water
source), you may monitor at one representative location and use the
monitoring results for that sampling location for all heat exchange
systems that use that same water feed.
    (3) Monitoring method. You must determine the total strippable
hydrocarbon concentration (in parts per million by volume (ppmv) as
methane) at each monitoring location using the ``Air Stripping Method
(Modified El Paso Method) for Determination of Volatile Organic
Compound Emissions from Water Sources'' (incorporated by reference, see
Sec.  63.14) using a flame ionization detector (FID) analyzer for on-
site determination as described in Section 6.1 of the Modified El Paso
Method.
    (4) Monitoring frequency and leak action level. For each heat
exchange system, you must comply with the applicable monitoring
frequency and leak action level, as defined in paragraphs (e)(4)(i)
through (iii) of this section. The monitoring frequencies specified in
paragraphs (e)(4)(i) through (iii) of this section also apply to the
inlet water feed line for a once-through heat exchange system, if you
elect to monitor the inlet water feed as provided in paragraph
(e)(2)(ii) of this section.
    (i) For each heat exchange system at an ethylene production
affected source that commenced construction or reconstruction on or
before December 6, 2000, you must monitor quarterly using a leak action
level defined as a total strippable hydrocarbon concentration (as
methane) in the stripping gas of 6.2 ppmv. If a leak is detected as
specified in paragraph (e)(5) of this section, then you must monitor
monthly until the leak has been repaired according to the requirements
in Sec.  63.1087(c) or (d). Once the leak has been repaired according
to the requirements in Sec.  63.1087(c) or (d), quarterly monitoring
for the heat exchange system may resume.
    (ii) For each heat exchange system at an ethylene production
affected source that commences construction or reconstruction after
December 6, 2000 and on or before October 9, 2019, you must monitor at
the applicable frequency specified in paragraph (e)(4)(ii)(A) or (B) of
this section using a leak action level defined as a total strippable
hydrocarbon concentration (as methane) in the stripping gas of 6.2
ppmv.
    (A) If you have completed the initial weekly monitoring for 6-
months of the heat exchange system as specified in Sec.
63.1086(a)(2)(ii) or (b)(1)(ii) then you must monitor monthly. If a
leak is

detected as specified in paragraph (e)(5) of this section, then you
must monitor weekly until the leak has been repaired according to the
requirements in Sec.  63.1087(c) or (d). Once the leak has been
repaired according to the requirements in Sec.  63.1087(c) or (d),
monthly monitoring for the heat exchange system may resume.
    (B) If you have not completed the initial weekly monitoring for 6-
months of the heat exchange system as specified in Sec.
63.1086(a)(2)(ii) or (b)(1)(ii), or if you elect to comply with
paragraph (e) of this section rather than paragraphs (a) through (d) of
this section upon startup, then you must initially monitor weekly for
6-months beginning upon startup and monitor monthly thereafter. If a
leak is detected as specified in paragraph (e)(5) of this section, then
you must monitor weekly until the leak has been repaired according to
the requirements in Sec.  63.1087(c) or (d). Once the leak has been
repaired according to the requirements in Sec.  63.1087(c) or (d),
monthly monitoring for the heat exchange system may resume.
    (iii) For each heat exchange system at an ethylene production
affected source that commences construction or reconstruction after
October 9, 2019, you must initially monitor weekly for 6-months
beginning upon startup and monitor monthly thereafter using a leak
action level defined as a total strippable hydrocarbon concentration
(as methane) in the stripping gas of 6.2 ppmv. If a leak is detected as
specified in paragraph (e)(5) of this section, then you must monitor
weekly until the leak has been repaired according to the requirements
in Sec.  63.1087(c) or (d). Once the leak has been repaired according
to the requirements in Sec.  63.1087(c) or (d), monthly monitoring for
the heat exchange system may resume.
    (5) Leak definition. A leak is defined as described in paragraph
(e)(5)(i) or (ii) of this section, as applicable.
    (i) For once-through heat exchange systems for which the inlet
water feed is monitored as described in paragraph (e)(2)(ii) of this
section, a leak is detected if the difference in the measurement value
of the sample taken from a location specified in paragraph (e)(2)(i) of
this section and the measurement value of the corresponding sample
taken from the location specified in paragraph (e)(2)(ii) of this
section equals or exceeds the leak action level.
    (ii) For all other heat exchange systems, a leak is detected if a
measurement value of the sample taken from a location specified in
paragraph (e)(1)(i), (ii), or (e)(2)(i) of this section equals or
exceeds the leak action level.
0
10. Section 63.1087 is amended by revising the introductory text and by
adding paragraphs (c) and (d) to read as follows:

Sec.  63.1087   What actions must I take if a leak is detected?

    Except as specified in Sec.  63.1085(f) and paragraphs (c) and (d)
of this section, if a leak is detected, you must comply with the
requirements in paragraphs (a) and (b) of this section unless repair is
delayed according to Sec.  63.1088.
* * * * *
    (c) Beginning no later than the compliance dates specified in Sec.
63.1081(a), if a leak is detected using the methods described in Sec.
63.1086(e), you must repair the leak to reduce the measured
concentration to below the applicable leak action level as soon as
practicable, but no later than 45 days after identifying the leak,
except as specified in Sec.  63.1088(d). Repair must include re-
monitoring at the monitoring location where the leak was identified
according to the method specified in Sec.  63.1086(e)(3) to verify that
the measured total strippable hydrocarbon concentration is below the
applicable leak action level. Repair may also include performing the
additional monitoring in paragraph (d) of this section to verify that
the total strippable hydrocarbon concentration is below the applicable
leak action level. Actions that can be taken to achieve repair include
but are not limited to:
    (1) Physical modifications to the leaking heat exchanger, such as
welding the leak or replacing a tube;
    (2) Blocking the leaking tube within the heat exchanger;
    (3) Changing the pressure so that water flows into the process
fluid;
    (4) Replacing the heat exchanger or heat exchanger bundle; or
    (5) Isolating, bypassing, or otherwise removing the leaking heat
exchanger from service until it is otherwise repaired.
    (d) Beginning no later than the compliance dates specified in Sec.
63.1081(a), if you detect a leak when monitoring a cooling tower return
line according to Sec.  63.1086(e)(1)(i), you may conduct additional
monitoring of each heat exchanger or group of heat exchangers
associated with the heat exchange system for which the leak was
detected, as provided in Sec.  63.1086(e)(1)(ii). If no leaks are
detected when monitoring according to the requirements of Sec.
63.1086(e)(1)(ii), the heat exchange system is considered to have met
the repair requirements through re-monitoring of the heat exchange
system, as provided in paragraph (c) of this section.
0
11. Section 63.1088 is amended by revising the introductory text and by
adding paragraph (d) to read as follows:

Sec.  63.1088   In what situations may I delay leak repair, and what
actions must I take for delay of repair?

    You may delay the repair of heat exchange systems if the leaking
equipment is isolated from the process. At any time before the
compliance dates specified in Sec.  63.1081(a), you may also delay
repair if repair is technically infeasible without a shutdown, and you
meet one of the conditions in paragraphs (a) through (c) of this
section. Beginning no later than the compliance dates specified in
Sec.  63.1081(a), paragraphs (a) through (c) of this section no longer
apply; instead, you may delay repair if the conditions in paragraph (d)
of this section are met.
* * * * *
    (d) Beginning no later than the compliance dates specified in Sec.
63.1081(a), you may delay repair when one of the conditions in
paragraph (d)(1) or (2) of this section is met and the leak is less
than the delay of repair action level specified in paragraph (d)(3) of
this section. You must determine if a delay of repair is necessary as
soon as practicable, but no later than 45 days after first identifying
the leak.
    (1) If the repair is technically infeasible without a shutdown and
the total strippable hydrocarbon concentration is initially and remains
less than the delay of repair action level for all monitoring periods
during the delay of repair, then you may delay repair until the next
scheduled shutdown of the heat exchange system. If, during subsequent
monitoring, the delay of repair action level is exceeded, then you must
repair the leak within 30 days of the monitoring event in which the
leak was equal to or exceeded the delay of repair action level.
    (2) If the necessary equipment, parts, or personnel are not
available and the total strippable hydrocarbon concentration is
initially and remains less than the delay of repair action level for
all monitoring periods during the delay of repair, then you may delay
the repair for a maximum of 120 calendar days. You must demonstrate
that the necessary equipment, parts, or personnel were not available.
If, during subsequent monitoring, the delay of repair action level is
exceeded, then you must repair the leak within 30 days of the
monitoring event in which the leak was equal to or exceeded the delay
of repair action level.

    (3) The delay of repair action level is a total strippable
hydrocarbon concentration (as methane) in the stripping gas of 62 ppmv.
The delay of repair action level is assessed as described in paragraph
(d)(3)(i) or (ii) of this section, as applicable.
    (i) For once-through heat exchange systems for which the inlet
water feed is monitored as described in Sec.  63.1086(e)(2)(ii), the
delay of repair action level is exceeded if the difference in the
measurement value of the sample taken from a location specified in
Sec.  63.1086(e)(2)(i) and the measurement value of the corresponding
sample taken from the location specified in Sec.  63.1086(e)(2)(ii)
equals or exceeds the delay of repair action level.
    (ii) For all other heat exchange systems, the delay of repair
action level is exceeded if a measurement value of the sample taken
from a location specified in Sec.  63.1086(e)(1)(i) and (ii) or Sec.
63.1086(e)(2)(i) equals or exceeds the delay of repair action level.
0
12. Section 63.1089 is amended by revising paragraphs (d) and (e) to
read as follows:

Sec.  63.1089   What records must I keep?

* * * * *
    (d) At any time before the compliance dates specified in Sec.
63.1081(a), you must keep documentation of delay of repair as specified
in Sec.  63.1088(a) through (c). Beginning no later than the compliance
dates specified in Sec.  63.1081(a), the requirement to keep
documentation of delay of repair as specified in Sec.  63.1088(a)
through (c) no longer applies; instead, you must keep documentation of
delay of repair as specified in paragraphs (d)(1) through (4) of this
section.
    (1) The reason(s) for delaying repair.
    (2) A schedule for completing the repair as soon as practical.
    (3) The date and concentration of the leak as first identified and
the results of all subsequent monitoring events during the delay of
repair.
    (4) An estimate of the potential strippable hydrocarbon emissions
from the leaking heat exchange system or heat exchanger for each
required delay of repair monitoring interval following the procedures
in paragraphs (d)(4)(i) through (iv) of this section.
    (i) Determine the leak concentration as specified in Sec.
63.1086(e) and convert the stripping gas leak concentration (in ppmv as
methane) to an equivalent liquid concentration, in parts per million by
weight (ppmw), using equation 7-1 from ``Air Stripping Method (Modified
El Paso Method) for Determination of Volatile Organic Compound
Emissions from Water Sources'' (incorporated by reference--see Sec.
63.14) and the molecular weight of 16 grams per mole (g/mol) for
methane.
    (ii) Determine the mass flow rate of the cooling water at the
monitoring location where the leak was detected. If the monitoring
location is an individual cooling tower riser, determine the total
cooling water mass flow rate to the cooling tower. Cooling water mass
flow rates may be determined using direct measurement, pump curves,
heat balance calculations, or other engineering methods. Volumetric
flow measurements may be used and converted to mass flow rates using
the density of water at the specific monitoring location temperature or
using the default density of water at 25 degrees Celsius, which is 997
kilograms per cubic meter or 8.32 pounds per gallon.
    (iii) For delay of repair monitoring intervals prior to repair of
the leak, calculate the potential strippable hydrocarbon emissions for
the leaking heat exchange system or heat exchanger for the monitoring
interval by multiplying the leak concentration in the cooling water,
ppmw, determined in (d)(4)(i) of this section, by the mass flow rate of
the cooling water determined in (d)(4)(ii) of this section and by the
duration of the delay of repair monitoring interval. The duration of
the delay of repair monitoring interval is the time period starting at
midnight on the day of the previous monitoring event or at midnight on
the day the repair would have been completed if the repair had not been
delayed, whichever is later, and ending at midnight of the day the of
the current monitoring event.
    (iv) For delay of repair monitoring intervals ending with a
repaired leak, calculate the potential strippable hydrocarbon emissions
for the leaking heat exchange system or heat exchanger for the final
delay of repair monitoring interval by multiplying the duration of the
final delay of repair monitoring interval by the leak concentration and
cooling water flow rates determined for the last monitoring event prior
to the re-monitoring event used to verify the leak was repaired. The
duration of the final delay of repair monitoring interval is the time
period starting at midnight of the day of the last monitoring event
prior to re-monitoring to verify the leak was repaired and ending at
the time of the re-monitoring event that verified that the leak was
repaired.
    (e) At any time before the compliance dates specified in Sec.
63.1081(a), if you validate a 40 CFR part 136 method for the HAP listed
in Table 1 to this subpart according to the procedures in appendix D to
this part, then you must keep a record of the test data and
calculations used in the validation. On the compliance dates specified
in Sec.  63.1081(a), this requirement no longer applies.
0
13. Section 63.1090 is amended by revising the introductory text and by
adding paragraph (f) to read as follows:

Sec.  63.1090   What reports must I submit?

    If you delay repair for your heat exchange system, you must report
the delay of repair in the semiannual report required by Sec.
63.1110(e). If the leak remains unrepaired, you must continue to report
the delay of repair in semiannual reports until you repair the leak.
Except as provided in paragraph (f) of this section, you must include
the information in paragraphs (a) through (e) of this section in the
semiannual report.
* * * * *
    (f) For heat exchange systems subject to Sec.  63.1085(e) and (f),
Periodic Reports must include the information specified in paragraphs
(f)(1) through (5) of this section, in lieu of the information
specified in paragraphs (a) through (e) of this section.
    (1) The number of heat exchange systems at the plant site subject
to the monitoring requirements in Sec.  63.1085(e) and (f).
    (2) The number of heat exchange systems at the plant site found to
be leaking.
    (3) For each monitoring location where the total strippable
hydrocarbon concentration was determined to be equal to or greater than
the applicable leak definitions specified in Sec.  63.1086(e)(5),
identification of the monitoring location (e.g., unique monitoring
location or heat exchange system ID number), the measured total
strippable hydrocarbon concentration, the date the leak was first
identified, and, if applicable, the date the source of the leak was
identified;
    (4) For leaks that were repaired during the reporting period
(including delayed repairs), identification of the monitoring location
associated with the repaired leak, the total strippable hydrocarbon
concentration measured during re-monitoring to verify repair, and the
re-monitoring date (i.e., the effective date of repair); and
    (5) For each delayed repair, identification of the monitoring
location associated with the leak for which repair is delayed, the date
when the delay of repair began, the date the repair is expected to be
completed (if the leak is not repaired during the reporting period),
the total strippable hydrocarbon concentration and date of each
monitoring event conducted on the

delayed repair during the reporting period, and an estimate of the
potential strippable hydrocarbon emissions over the reporting period
associated with the delayed repair.
0
14. Section 63.1095 is amended by:
0
a. Revising paragraphs (a)(1) introductory text;
0
b. Adding paragraph (a)(1)(vi);
0
c. Revising paragraphs (a)(3), (b) introductory text, and (b)(1); and
0
d. Adding paragraph (b)(3).
    The revisions and additions read as follows:

Sec.  63.1095   What specific requirements must I comply with?

* * * * *
    (a) * * *
    (1) Route the continuous butadiene stream to a treatment process or
wastewater treatment system used to treat benzene waste streams that
complies with the standards specified in 40 CFR 61.348. Comply with the
requirements of 40 CFR part 61, subpart FF; with the changes in Table 2
to this subpart, and as specified in paragraphs (a)(1)(i) through (vi)
of this section.
* * * * *
    (vi) Beginning no later than the compliance dates specified in
Sec.  63.1081(b), if you use a steam-assisted, air-assisted, non-
assisted, or pressure-assisted multi-point flare to comply with 40 CFR
part 61, subpart FF, then you must comply with the requirements of 40
CFR 63.1103(e)(4) in lieu of 40 CFR 61.349(a)(2)(iii) and (d), 40 CFR
61.354(c)(3), 40 CFR 61.356(f)(2)(i)(D) and (j)(7), and 40 CFR
61.357(d)(7)(iv)(F).
* * * * *
    (3) Before [date 3 years after date of publication of final rule in
the Federal Register], if the total annual benzene quantity from waste
at your facility is less than 10 Mg/yr, as determined according to 40
CFR 61.342(a), comply with the requirements of this section at all
times except during periods of startup, shutdown, and malfunction, if
the startup, shutdown, or malfunction precludes the ability of the
affected source to comply with the requirements of this section and the
owner or operator follows the provisions for periods of startup,
shutdown, and malfunction, as specified in Sec.  63.1111. Beginning on
[date 3 years after date of publication of final rule in the Federal
Register], if the total annual benzene quantity from waste at your
facility is less than 10 Mg/yr, as determined according to 40 CFR
61.342(a), you must comply with the requirements of this section at all
times.
    (b) Waste streams that contain benzene. For waste streams that
contain benzene, you must comply with the requirements of 40 CFR part
61, subpart FF, except as specified in Table 2 to this subpart and
paragraph (b)(3) of this section. You must manage and treat waste
streams that contain benzene as specified in either paragraph (b)(1) or
(2) of this section.
    (1) If the total annual benzene quantity from waste at your
facility is less than 10 Mg/yr, as determined according to 40 CFR
61.342(a), manage and treat spent caustic waste streams and dilution
steam blowdown waste streams according to 40 CFR 61.342(c)(1) through
(c)(3)(i). Before [date 3 years after date of publication of final rule
in the Federal Register], the requirements of this paragraph (b)(1)
shall apply at all times except during periods of startup, shutdown,
and malfunction, if the startup, shutdown, or malfunction precludes the
ability of the affected source to comply with the requirements of this
section and the owner or operator follows the provisions for periods of
startup, shutdown, and malfunction, as specified in Sec.  63.1111.
Beginning on [date 3 years after date of publication of final rule in
the Federal Register], the requirements of this paragraph (b)(1) shall
apply at all times.
* * * * *
    (3) Beginning no later than the compliance dates specified in Sec.
63.1081(b), if you use a steam-assisted, air-assisted, non-assisted, or
pressure-assisted multi-point flare to comply with 40 CFR part 61,
subpart FF, then you must comply with the requirements of 40 CFR
63.1103(e)(4) in lieu of 40 CFR 61.349(a)(2)(iii) and (d), 40 CFR
61.354(c)(3), 40 CFR 61.356(f)(2)(i)(D) and (j)(7), and 40 CFR
61.357(d)(7)(iv)(F).
0
15. Table 2 to subpart XX of part 63 is amended by revising the first
column heading, third entry to row 1, and the first two entries to row
2 to read as follows:

    Table 2 to Subpart XX of Part 63--Requirements of 40 CFR Part 61,
    Subpart FF, Not Included in the Requirements for This Subpart and
                         Alternate Requirements
------------------------------------------------------------------------
 If the total annual benzene
quantity for waste from your   Do not comply with:     Instead, comply
      facility is * * *                                     with:
------------------------------------------------------------------------
1. Less than 10 Mg/yr.......  40 CFR 61.340.......  Sec.   63.1093.
                              40 CFR                There is no
                               61.342(c)(3)(ii),     equivalent
                               (d), and (e).         requirement.
                              40 CFR 61.342(f)....  Sec.   63.1096.

                              * * * * * * *
2. Greater than or equal to   40 CFR 61.340.......  Sec.   63.1093.
 10 Mg/yr.
                              40 CFR 61.342(f)....  Sec.   63.1096.

                              * * * * * * *
------------------------------------------------------------------------

0
16. Section 63.1100 is amended by:
0
a. Revising the heading to Table 1 to Sec.  63.1100(a);
0
b. Revising the rows ``Carbon Black Production,'' ``Cyanide Chemicals
Manufacturing,'' ``Ethylene Production,'' and ``Spandex Production'';
and revising footnote c to Table 1 to Sec.  63.1100(a);
0
c. Revising paragraphs (b), (g) introductory text, and (g)(4)(ii);
0
d. Adding paragraph (g)(4)(iii);
0
e. Revising paragraph (g)(5); and
0
f. Adding paragraph (g)(7).
    The revisions and additions read as follows:

Sec.  63.1100   Applicability.

    (a) * * *

                                                              Table 1 to Sec.   63.1100(a)--Source Category MACT \a\ Applicability
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Source category
         Source category              Storage vessels        Process vents        Transfer racks         Equipment leaks         Wastewater streams            Other          MACT requirements
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

                                                                                * * * * * * *
Carbon Black Production..........  No..................  Yes.................  No..................  No.....................  No.....................  No..................  Sec.   63.1103(f).
Cyanide Chemicals Manufacturing..  Yes.................  Yes.................  Yes.................  Yes....................  Yes....................  No..................  Sec.   63.1103(g).
Ethylene Production..............  Yes.................  Yes.................  Yes.................  Yes....................  Yes....................  Yes \c\.............  Sec.   63.1103(e).

                                                                                * * * * * * *
Spandex Production...............  Yes.................  Yes.................  No..................  No.....................  No.....................  Yes \d\.............  Sec.   63.1103(h).
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Maximum achievable control technology.
\b\ Fiber spinning lines using spinning solution or suspension containing acrylonitrile.
\c\ Heat exchange systems as defined in Sec.   63.1082(b).
\d\ Fiber spinning lines.

    (b) Subpart A requirements. The following provisions of subpart A
of this part (General Provisions), Sec. Sec.  63.1 through 63.5, and
Sec. Sec.  63.12 through 63.15, apply to owners or operators of
affected sources subject to this subpart. Beginning no later than the
compliance dates specified in Sec.  63.1102(c), for ethylene production
affected sources, Sec. Sec.  63.7, 63.8, 63.10(c), and 63.10(e) also
apply, except for Sec.  63.8(c)(1)(iii).
* * * * *
    (g) Overlap with other regulations. Paragraphs (g)(1) through (7)
of this section specify the applicability of this subpart YY emission
point requirements when other rules may apply. Where subpart YY of this
part allows an owner or operator an option to comply with one or
another regulation to comply with subpart YY of this part, an owner or
operator must report which regulation they choose to comply with in the
Notification of Compliance Status report required by Sec.
63.1110(a)(4).
    (4) * * *
    (ii) After the compliance dates specified in Sec.  63.1102,
equipment that must be controlled according to this subpart and subpart
H of this part is in compliance with the equipment leak requirements of
this subpart if it complies with either set of requirements. For
ethylene production affected sources, the requirement in Sec.
63.1103(e)(9)(i) also applies. The owner or operator must specify the
rule with which they will comply in the Notification of Compliance
Status report required by Sec.  63.1110(a)(4).
    (iii) Beginning no later than the compliance dates specified in
Sec.  63.1102(c), for ethylene production affected sources, equipment
that must be controlled according to this subpart and subpart VVa of 40
CFR part 60 is required only to comply with the equipment leak
requirements of this subpart, except the owner or operator must also
comply with the calibration drift assessment requirements specified at
Sec.  60.485a(b)(2). When complying with the calibration drift
assessment requirements at Sec.  60.485a(b)(2), the requirement at
Sec.  60.486a(e)(8)(v) to record the instrument reading for each scale
used applies.
    (5) Overlap of subpart YY with other regulations for wastewater for
source categories other than ethylene production. (i) After the
compliance dates specified in Sec.  63.1102 for an affected source
subject to this subpart, a wastewater stream that is subject to the
wastewater requirements of this subpart and the wastewater requirements
of subparts F, G, and H of this part (collectively known as the
``HON'') shall be deemed to be in compliance with the requirements of
this subpart if it complies with either set of requirements. In any
instance where a source subject to this subpart is collocated with a
Synthetic Organic Chemical Manufacturing Industry (SOCMI) source, and a
single wastewater treatment facility treats both Group 1 wastewaters
and wastewater residuals from the source subject to this subpart and
wastewaters from the SOCMI source, a certification by the treatment
facility that they will manage and treat the waste in conformity with
the specific control requirements set forth in 40 CFR 63.133 through
63.147 will also be deemed sufficient to satisfy the certification
requirements for wastewater treatment under this subpart.
* * * * *
    (7) Overlap of subpart YY with other regulations for flares for the
ethylene production source category. (i) Beginning no later than the
compliance dates specified in Sec.  63.1102(c), flares that are subject
to the provisions of 40 CFR 60.18 or 63.11 and used as a control device
for an emission point subject to the requirements in Table 7 to Sec.
63.1103(e) are required to comply only with the provisions specified in
Sec.  63.1103(e)(4). At any time before the compliance dates specified
in Sec.  63.1102(c), flares that are subject to the provisions of 40
CFR 60.18 or 63.11 and elect to comply with the requirements in Sec.
63.1103(e)(4) are required to comply only with the provisions specified
in this subpart.
0
17. Section 63.1101 is amended by revising the definitions of
``Pressure relief device or value'' and ``Shutdown'' to read as
follows:

Sec.  63.1101   Definitions.

* * * * *
    Pressure relief device or valve means a safety device used to
prevent operating pressures from exceeding the maximum allowable
working pressure of the process equipment. A common pressure relief
device is a spring-loaded pressure relief valve. Devices that are
actuated either by a pressure of less than or equal to 2.5 pounds per
square inch gauge or by a vacuum are not pressure relief devices. This
definition does not apply to ethylene production affected sources.
* * * * *
    Shutdown means the cessation of operation of an affected source or
equipment that is used to comply with this subpart, or the emptying and
degassing of a storage vessel. For the purposes of this subpart,
shutdown includes, but is not limited to, periodic maintenance,
replacement of equipment, or repair. Shutdown does not include the
routine rinsing or washing of equipment in batch operation between
batches. Shutdown includes the decoking of ethylene cracking furnaces.
* * * * *
0
18. Section 63.1102 is amended by revising paragraph (a) introductory
text and adding paragraph (c) to read as follows:

Sec.  63.1102   Compliance schedule.

    (a) General requirements. Affected sources, as defined in Sec.
63.1103(a)(1)(i) for acetyl resins production, Sec.  63.1103(b)(1)(i)
for acrylic and modacrylic fiber production, Sec.  63.1103(c)(1)(i) for
hydrogen fluoride production, Sec.  63.1103(d)(1)(i) for polycarbonate
production, Sec.  63.1103(e)(1)(i) for ethylene production, Sec.
63.1103(f)(1)(i) for carbon black production, Sec.  63.1103(g)(1)(i)
for cyanide chemicals manufacturing, or Sec.  63.1103(h)(1)(i) for
spandex production shall comply with the appropriate provisions of this
subpart and the subparts referenced by this subpart according to the
schedule in paragraphs (a)(1) or (2) of this section, as appropriate,
except as provided in paragraphs (b) and (c) of this section. Proposal
and effective dates are specified in Table 1 to this section.
* * * * *
    (c) All ethylene production affected sources that commenced
construction or reconstruction on or before October 9, 2019, must be in
compliance with the requirements listed in paragraphs (c)(1) through
(13) of this section upon initial startup or [date 3 years after date
of publication of final rule in the Federal Register], whichever is
later. All ethylene production affected sources that commenced
construction or reconstruction after October 9, 2019, must be in
compliance with the requirements listed in paragraphs (c)(1) through
(13) of this section upon initial startup, or [date of publication of
final rule in the Federal Register], whichever is later.
    (1) Overlap requirements specified in Sec.  63.1100(g)(4)(iii) and
(7), if applicable.
    (2) The storage vessel requirements specified in paragraphs (a)(2),
(b)(2), and (c)(1)(ii) of Table 7 to Sec.  63.1103(e).
    (3) The ethylene process vent requirements specified in paragraph
(d)(1)(ii) of Table 7 to Sec.  63.1103(e).
    (4) The transfer rack requirements specified in Sec.
63.1105(a)(5).
    (5) The equipment requirements specified in paragraph (f)(1)(ii) of
Table 7 to Sec.  63.1103(e), and Sec.  63.1107(h).
    (6) The bypass line requirements specified in paragraph (i) of
Table 7 to Sec.  63.1103(e), and Sec.  63.1103(e)(6).
    (7) The decoking requirements for ethylene cracking furnaces
specified in paragraph (j) of Table 7 to Sec.  63.1103(e), and Sec.
63.1103(e)(7) and (8).
    (8) The flare requirements specified in Sec.  63.1103(e)(4).
    (9) The maintenance vent requirements specified in Sec.
63.1103(e)(5).
    (10) The requirements specified in Sec.  63.1103(e)(9).
    (11) The requirements in Sec.  63.1108(a)(4)(i), (b)(1)(ii),
(b)(2), and (b)(4)(ii)(B).
    (12) The recordkeeping requirements specified in Sec.  63.1109(e)
through (i).
    (13) The reporting requirements specified in Sec.  63.1110(a)(10),
(d)(1)(iv) and (v), and (e)(4) through (8).
* * * * *
0
19. Section 63.1103 is amended:
0
a. By revising the definition of ``In organic hazardous air pollutant
or in organic HAP service'' in paragraph (b)(2);
0
b. By revising paragraphs (e)(1)(i) introductory text, (e)(1)(i)(F),
and (e)(1)(ii)(J);
0
c. In paragraph (e)(2) by;
0
i. Adding in alphabetical order a definition for ``Decoking
operation'';
0
ii. Revising the definition of ``Ethylene process vent'';
0
iii. Adding in alphabetical order a definition for ``Force majeure
event'';
0
iv. Removing the definition of ``Heat exchange system'';
0
v. Adding in alphabetical order, a definition for ``Periodically
discharged,'' ``Pressure-assisted multi-point flare,'' ``Pressure
relief device,'' ``Radiant tube(s),'' and ``Relief valve'';
0
d. By revising paragraph (e)(3);
0
e. By revising Table 7 to Sec.  63.1103(e); and
0
f. By adding paragraphs (e)(4) through (9).
    The revisions and additions read as follows:

Sec.  63.1103   Source category-specific applicability, definitions,
and requirements.

* * * * *
    (b) * * *
    (2) * * *
* * * * *
    In organic hazardous air pollutant or in organic HAP service means,
for acrylic and modacrylic fiber production affected sources, that a
piece of equipment either contains or contacts a fluid (liquid or gas)
that is at least 10 percent by weight of total organic HAP as
determined according to the provisions of Sec.  63.180(d). The
provisions of Sec.  63.180(d) also specify how to determine that a
piece of equipment is not in organic HAP service.
* * * * *
    (e) Ethylene production applicability, definitions, and
requirements--(1) Applicability--(i) Affected source. For the ethylene
production (as defined in paragraph (e)(2) of this section) source
category, the affected source comprises all emission points listed in
paragraphs (e)(1)(i)(A) through (G) of this section that are associated
with an ethylene production unit that is located at a major source, as
defined in section 112(a) of the Act.
* * * * *
    (F) All heat exchange systems (as defined in Sec.  63.1082(b))
associated with an ethylene production unit.
* * * * *
    (ii) * * *
    (J) Air emissions from all ethylene cracking furnaces.
* * * * *
    (2) Definitions.
    Decoking operation means the coke combustion activity that occurs
inside the radiant tube(s) in the ethylene cracking furnace firebox.
    Ethylene process vent means a gas stream with a flow rate greater
than 0.005 standard cubic meters per minute containing greater than 20
parts per million by volume HAP that is continuously discharged, or
periodically discharged on and after [date 3 years after date of
publication of final rule in the Federal Register], during operation of
an ethylene production unit. Ethylene process vents are gas streams
that are discharged to the atmosphere (or the point of entry into a
control device, if any) either directly or after passing through one or
more recovery devices. Ethylene process vents do not include:
    (A) Pressure relief device discharges;
    (B) Gaseous streams routed to a fuel gas system, including any
flares using fuel gas, of which less than 50 percent of the fuel gas is
derived from an ethylene production unit;
    (C) Gaseous streams routed to a fuel gas system whereby any flares
using fuel gas, of which 50 percent or more of the fuel gas is derived
from an ethylene production unit, comply with Sec.  63.1103(e)(4)
beginning no later than the compliance dates specified in Sec.
63.1102(c);
    (D) Leaks from equipment regulated under this subpart;
    (E) Episodic or nonroutine releases such as those associated with
startup, shutdown, and malfunction until [date 3 years after date of
publication of final rule in the Federal Register]; and
    (F) In situ sampling systems (online analyzers) until [date 3 years
after date of publication of final rule in the Federal Register].
* * * * *
    Force majeure event means a release of HAP, either directly to the
atmosphere from a pressure relief device or discharged via a flare,
that is demonstrated to the satisfaction of the Administrator to result
from an event beyond the owner or operator's control, such as natural
disasters; acts of war or terrorism; loss of a utility external to the

ethylene production unit (e.g., external power curtailment), excluding
power curtailment due to an interruptible service agreement; and fire
or explosion originating at a near or adjoining facility outside of the
ethylene production unit that impacts the ethylene production unit's
ability to operate.
* * * * *
    Periodically discharged means gas stream discharges that are
intermittent for which the total organic HAP concentration is greater
than 20 parts per million by volume and total volatile organic compound
emissions are 50 pounds per day or more. These intermittent discharges
are associated with routine operations, maintenance activities,
startups, shutdowns, malfunctions, or process upsets and do not include
pressure relief device discharges or discharges classified as
maintenance vents.
    Pressure-assisted multi-point flare means a flare system consisting
of multiple flare burners in staged arrays whereby the vent stream
pressure is used to promote mixing and smokeless operation at the flare
burner tips. Pressure-assisted multi-point flares are designed for
smokeless operation at velocities up to Mach = 1 conditions (i.e.,
sonic conditions), can be elevated or at ground level, and typically
use cross-lighting for flame propagation to combust any flare vent
gases sent to a particular stage of flare burners.
    Pressure relief device means a valve, rupture disk, or similar
device used only to release an unplanned, nonroutine discharge of gas
from process equipment in order to avoid safety hazards or equipment
damage. A pressure relief device discharge can result from an operator
error, a malfunction such as a power failure or equipment failure, or
other unexpected cause. Such devices include conventional, spring-
actuated relief valves, balanced bellows relief valves, pilot-operated
relief valves, rupture disks, and breaking, buckling, or shearing pin
devices.
    Radiant tube(s) means any portion of the tube coil assembly located
within the ethylene cracking furnace firebox whereby a thermal cracking
reaction of hydrocarbons (in the presence of steam) occurs.
Hydrocarbons and steam pass through the radiant tube(s) of the ethylene
cracking furnace during normal operation and coke is removed from the
inside of the radiant tube(s) during decoking operation.
    Relief valve means a type of pressure relief device that is
designed to re-close after the pressure relief.
* * * * *
    (3) Requirements. The owner or operator must control organic HAP
emissions from each affected source emission point by meeting the
applicable requirements specified in Table 7 to this section. An owner
or operator must perform the applicability assessment procedures and
methods for process vents specified in Sec.  63.1104, except for
paragraphs (d), (g), (h) through (j), (l)(1), and (n). An owner or
operator must perform the applicability assessment procedures and
methods for equipment leaks specified in Sec.  63.1107. General
compliance, recordkeeping, and reporting requirements are specified in
Sec.  Sec.  63.1108 through 63.1112. Before [date 3 years after date of
publication of final rule in the Federal Register], minimization of
emissions from startup, shutdown, and malfunctions must be addressed in
the startup, shutdown, and malfunction plan required by Sec.  63.1111;
the plan must also establish reporting and recordkeeping of such
events. A startup, shutdown, and malfunction plan is not required on
and after [date 3 years after date of publication of final rule in the
Federal Register] and the requirements specified in Sec.  63.1111 no
longer apply; however, for historical compliance purposes, a copy of
the plan must be retained and available on-site for five years after
[date 3 years after date of publication of final rule in the Federal
Register]. Except as specified in paragraph (e)(4)(i) of this section,
procedures for approval of alternate means of emission limitations are
specified in Sec.  63.1113.

   Table 7 to Sec.   63.1103(e)--What Are My Requirements if I Own or
     Operate an Ethylene Production Existing or New Affected Source?
------------------------------------------------------------------------
 If you own or operate . . .      And if . . .       Then you must . . .
------------------------------------------------------------------------
(a) A storage vessel (as      (1) Except as         (i) Fill the vessel
 defined in Sec.   63.1101)    specified in          through a submerged
 that stores liquid            paragraph (a)(2) of   pipe; or
 containing organic HAP.       this table, the      (ii) Comply with the
                               maximum true vapor    requirements in
                               pressure of total     paragraph (b)(1)(i)
                               organic HAP is        or (ii) of this
                               >=3.4 kilopascals     table.
                               but <76.6
                               kilopascals; and
                               the capacity of the
                               vessel is >=4 cubic
                               meters but <95
                               cubic meters.
                              (2) Beginning no      (i) Fill the vessel
                               later than the        through a submerged
                               compliance dates      pipe; or
                               specified in Sec.    (ii) Comply with the
                               63.1102(c), the       requirements in
                               maximum true vapor    paragraph (b)(2)(i)
                               pressure of total     or (ii) of this
                               organic HAP is        table.
                               >=0.69 kilopascals
                               but <76.6
                               kilopascals; and
                               the capacity of the
                               vessel is >=4 cubic
                               meters but <59
                               cubic meters.
(b) A storage vessel (as      (1) Except as         (i) Comply with the
 defined in Sec.   63.1101)    specified in          requirements of
 that stores liquid            paragraph (b)(2) of   subpart WW of this
 containing organic HAP.       this table, the       part; or
                               maximum true vapor   (ii) Reduce
                               pressure of total     emissions of total
                               organic HAP is        organic HAP by 98
                               >=3.4 kilopascals     weight-percent by
                               but <76.6             venting emissions
                               kilopascals; and      through a closed
                               the capacity of the   vent system to any
                               vessel is >=95        combination of
                               cubic meters.         control devices and
                                                     meet the
                                                     requirements of
                                                     Sec.
                                                     63.982(a)(1).

                              (2) Beginning no      (i) Comply with the
                               later than the        requirements of
                               compliance dates      subpart WW of this
                               specified in Sec.     part; \a\ or (ii)
                               63.1102(c), the       Reduce emissions of
                               maximum true vapor    total organic HAP
                               pressure of total     by 98 weight-
                               organic HAP is        percent by venting
                               >=0.69 kilopascals    emissions through a
                               but <76.6             closed vent system
                               kilopascals; and      to a flare and meet
                               the capacity of the   the requirements of
                               vessel is >=59        Sec.   63.983 and
                               cubic meters.         paragraphs (e)(4)
                                                     and (9) of this
                                                     section; or (iii)
                                                     Reduce emissions of
                                                     total organic HAP
                                                     by 98 weight-
                                                     percent by venting
                                                     emissions through a
                                                     closed vent system
                                                     to any combination
                                                     of non-flare
                                                     control devices and
                                                     meet the
                                                     requirements
                                                     specified in Sec.
                                                     63.982(c)(1) and
                                                     (e)(9) of this
                                                     section; or (iv)
                                                     Reduce emissions of
                                                     total organic HAP
                                                     by 98 weight-
                                                     percent by routing
                                                     emissions to a fuel
                                                     gas system \b\ or
                                                     process and meet
                                                     the requirements
                                                     specified in Sec.
                                                     63.982(d) and
                                                     (e)(9) of this
                                                     section.
(c) A storage vessel (as      (1) The maximum true  (i) Except as
 defined in Sec.   63.1101)    vapor pressure of     specified in
 that stores liquid            total organic HAP     paragraph
 containing organic HAP.       is >=76.6             (c)(1)(ii) of this
                               kilopascals.          table, reduce
                                                     emissions of total
                                                     organic HAP by 98
                                                     weight-percent by
                                                     venting emissions
                                                     through a closed
                                                     vent system to any
                                                     combination of
                                                     control devices and
                                                     meet the
                                                     requirements of
                                                     Sec.
                                                     63.982(a)(1). (ii)
                                                     Beginning no later
                                                     than the compliance
                                                     dates specified in
                                                     Sec.   63.1102(c),
                                                     comply with
                                                     paragraph
                                                     (c)(1)(ii)(A), (B),
                                                     or (C) of this
                                                     section. (A) Reduce
                                                     emissions of total
                                                     organic HAP by 98
                                                     weight-percent by
                                                     venting emissions
                                                     through a closed
                                                     vent system to a
                                                     flare and meet the
                                                     requirements of
                                                     Sec.   63.983 and
                                                     paragraphs (e)(4)
                                                     and (9) of this
                                                     section; or (B)
                                                     Reduce emissions of
                                                     total organic HAP
                                                     by 98 weight-
                                                     percent by venting
                                                     emissions through a
                                                     closed vent system
                                                     to any combination
                                                     of non-flare
                                                     control devices and
                                                     meet the
                                                     requirements
                                                     specified in Sec.
                                                     63.982(c)(1) and
                                                     (e)(9) of this
                                                     section; or (C)
                                                     Reduce emissions of
                                                     total organic HAP
                                                     by 98 weight-
                                                     percent by routing
                                                     emissions to a fuel
                                                     gas system \b\ or
                                                     process and meet
                                                     the requirements
                                                     specified in Sec.
                                                     63.982(d) and
                                                     (e)(9) of this
                                                     section.
(d) An ethylene process vent  (1) The process vent  (i) Except as
 (as defined in paragraph      is at an existing     specified in
 (e)(2) of this section).      source and the vent   paragraph
                               stream has a flow     (d)(1)(ii) of this
                               rate >=0.011 scmm     table, reduce
                               and a total organic   emissions of
                               HAP concentration     organic HAP by 98
                               >=50 parts per        weight-percent; or
                               million by volume     reduce organic HAP
                               on a dry basis; or    or TOC to a
                               the process vent is   concentration of 20
                               at a new source and   parts per million
                               the vent stream has   by volume on a dry
                               a flow rate >=0.008   basis corrected to
                               scmm and a total      3% oxygen;
                               organic HAP           whichever is less
                               concentration >=30    stringent, by
                               parts per million     venting emissions
                               by volume on a dry    through a closed
                               basis.                vent system to any
                                                     combination of
                                                     control devices and
                                                     meet the
                                                     requirements
                                                     specified in Sec.
                                                     63.982(b) and
                                                     (c)(2). (ii)
                                                     Beginning no later
                                                     than the compliance
                                                     dates specified in
                                                     Sec.   63.1102(c),
                                                     comply with the
                                                     maintenance vent
                                                     requirements
                                                     specified in
                                                     paragraph (e)(5) of
                                                     this section and
                                                     either paragraph
                                                     (d)(1)(ii)(A) or
                                                     (B) of this table.
                                                     (A) Reduce
                                                     emissions of
                                                     organic HAP by 98
                                                     weight-percent; or
                                                     reduce organic HAP
                                                     or TOC to a
                                                     concentration of 20
                                                     parts per million
                                                     by volume on a dry
                                                     basis corrected to
                                                     3% oxygen;
                                                     whichever is less
                                                     stringent, by
                                                     venting emissions
                                                     through a closed
                                                     vent system to a
                                                     flare and meet the
                                                     requirements of
                                                     Sec.   63.983 and
                                                     paragraphs (e)(4)
                                                     and (9) of this
                                                     section; or (B)
                                                     Reduce emissions of
                                                     organic HAP by 98
                                                     weight-percent; or
                                                     reduce organic HAP
                                                     or TOC to a
                                                     concentration of 20
                                                     parts per million
                                                     by volume on a dry
                                                     basis corrected to
                                                     3% oxygen;
                                                     whichever is less
                                                     stringent, by
                                                     venting emissions
                                                     through a closed
                                                     vent system to any
                                                     combination of non-
                                                     flare control
                                                     devices and meet
                                                     the requirements
                                                     specified in Sec.
                                                     63.982(c)(2) and
                                                     (e)(9) of this
                                                     section.

(e) A transfer rack (as       (1) Materials loaded  (i) Reduce emissions
 defined in paragraph (e)(2)   have a true vapor     of organic HAP by
 of this section).             pressure of total     98 weight-percent;
                               organic HAP >=3.4     or reduce organic
                               kilopascals and       HAP or TOC to a
                               >=76 cubic meters     concentration of 20
                               per day (averaged     parts per million
                               over any              by volume on a dry
                               consecutive 30-day    basis corrected to
                               period) of HAP-       3% oxygen;
                               containing material   whichever is less
                               is loaded.            stringent, by
                                                     venting emissions
                                                     through a closed
                                                     vent system to any
                                                     combination of
                                                     control devices as
                                                     specified in Sec.
                                                     63.1105 and meet
                                                     the requirements
                                                     specified in
                                                     paragraph (e)(9) of
                                                     this section.; or
                                                    (ii) Install process
                                                     piping designed to
                                                     collect the HAP-
                                                     containing vapors
                                                     displaced from tank
                                                     trucks or railcars
                                                     during loading and
                                                     to route it to a
                                                     process, a fuel gas
                                                     system, or a vapor
                                                     balance system, as
                                                     specified in Sec.
                                                     63.1105 and meet
                                                     the requirements
                                                     specified in
                                                     paragraph (e)(9) of
                                                     this section.\b\
(f) Equipment (as defined in  (1) The equipment     (i) Except as
 Sec.   63.1101) that          contains or           specified in
 contains or contacts          contacts >=5 weight-  paragraph
 organic HAP.                  percent organic       (f)(1)(ii) of this
                               HAP; and the          table, comply with
                               equipment is not in   the requirements of
                               vacuum service.       subpart UU of this
                                                     part. (ii)
                                                     Beginning no later
                                                     than the compliance
                                                     dates specified in
                                                     Sec.   63.1102(c),
                                                     comply with the
                                                     requirements of
                                                     paragraph (e)(9) of
                                                     this section and
                                                     subpart UU of this
                                                     part, except
                                                     instead of
                                                     complying with the
                                                     pressure relief
                                                     device requirements
                                                     of Sec.   63.1030
                                                     of subpart UU, meet
                                                     the requirements of
                                                     Sec.   63.1107(h),
                                                     and in lieu of the
                                                     flare requirement
                                                     of Sec.
                                                     63.1034(b)(2)(iii),
                                                     comply with the
                                                     requirements
                                                     specified in
                                                     paragraph (e)(4) of
                                                     this section.\b\
(g) Processes that generate   (1) The waste stream  (i) Comply with the
 waste (as defined in          contains any of the   waste requirements
 paragraph (e)(2) of this      following HAP:        of subpart XX of
 section.                      Benzene, cumene,      this part. For
                               ethyl benzene,        ethylene production
                               hexane,               unit waste stream
                               naphthalene,          requirements, terms
                               styrene, toluene, o-  have the meanings
                               xylene, m-xylene, p-  specified in
                               xylene, or 1,3-       subpart XX.
                               butadiene.
(h) A heat exchange system    ....................  Comply with the heat
 (as defined in Sec.                                 exchange system
 63.1082(b)).                                        requirements of
                                                     subpart XX of this
                                                     part.
(i) A closed vent system      (1) The bypass line   (i) Beginning no
 that contains one or more     could divert a vent   later than the
 bypass lines.                 stream directly to    compliance dates
                               the atmosphere or     specified in Sec.
                               to a control device   63.1102(c), comply
                               not meeting the       with the
                               requirements in       requirements
                               this table.           specified in
                                                     paragraphs (e)(6)
                                                     and (9) of this
                                                     section.
(j) A decoking operation      ....................  Beginning no later
 associated with an ethylene                         than the compliance
 cracking furnace.                                   dates specified in
                                                     Sec.   63.1102(c),
                                                     comply with the
                                                     requirements
                                                     specified in
                                                     paragraphs (e)(7)
                                                     and (8) of this
                                                     section.
------------------------------------------------------------------------
\a\ For owners or operators that choose to comply with the requirements
  of subpart WW of this part for storage vessels with a capacity >=59
  cubic meters, the timing for installation of the required controls is
  specified within subpart WW of this part. All references to
  ``promulgation of the referencing subpart'' and ``the promulgation
  date of the referencing subpart'' in subpart WW of this part means
  [date of publication of final rule in the Federal Register].
\b\ Beginning no later than the compliance dates specified in Sec.
  63.1102(c), any flare using fuel gas from a fuel gas system, of which
  50 percent or more of the fuel gas is derived from an ethylene
  production unit, must be in compliance with paragraph (e)(4) of this
  section.

    (4) Flares. Beginning no later than the compliance dates specified
in Sec.  63.1102(c), if a steam-assisted, air-assisted, non-assisted,
or pressure-assisted multi-point flare is used as a control device for
an emission point subject to the requirements in Table 7 to this
section, then the owner or operator must meet the applicable
requirements for flares as specified in Sec. Sec.  63.670 and 63.671 of
subpart CC, including the provisions in Tables 12 and 13 to subpart CC
of this part, except as specified in paragraphs (e)(4)(i) through (xi)
of this section. This requirement also applies to any flare using fuel
gas from a fuel gas system, of which 50 percent or more of the fuel gas
is derived from an ethylene production unit, being used to control an
emission point subject to the requirements in Table 7 of this section.
For purposes of compliance with this paragraph, the following terms are
defined in Sec.  63.641 of subpart CC: Assist air, assist steam, center
steam, combustion zone, combustion zone gas, flare, flare purge gas,
flare supplemental gas, flare sweep gas, flare vent gas, lower steam,
net heating value, perimeter assist air, pilot gas, premix assist air,
total steam, and upper steam.
    (i) The owner or operator may elect to comply with the alternative
means of emissions limitation requirements specified in of Sec.
63.670(r) of subpart CC in lieu of the requirements in Sec.  63.670(d)
through (f) of subpart CC, as applicable. However, instead of complying
with Sec.  63.670(r)(3) of subpart CC, the owner or operator must
submit the alternative means of emissions limitation request following
the requirements in Sec.  63.1113.
    (ii) Instead of complying with Sec.  63.670(o)(2)(i) of subpart CC,
the owner or operator must develop and implement the flare management
plan no later than the compliance dates specified in Sec.  63.1102(c).

    (iii) Instead of complying with Sec.  63.670(o)(2)(iii) of subpart
CC, if required to develop a flare management plan and submit it to the
Administrator, then the owner or operator must also submit all versions
of the plan in portable document format (PDF) to the EPA via the
Compliance and Emissions Data Reporting Interface (CEDRI), which can be
accessed through the EPA's Central Data Exchange (CDX) (https://cdx.epa.gov/). If you claim some of the information in your flare
management plan is confidential business information (CBI), submit a
version with the CBI omitted via CEDRI. A complete plan, including
information claimed to be CBI and clearly marked as CBI, must be mailed
to the following address: U.S. Environmental Protection Agency, Office
of Air Quality Planning and Standards, Sector Policies and Programs
Division, U.S. EPA Mailroom (E143-01), Attention: Ethylene Production
Sector Lead, 109 T.W. Alexander Drive, Research Triangle Park, NC
27711.
    (iv) Substitute ``ethylene production unit'' for each occurrence of
``petroleum refinery.''
    (v) Each occurrence of ``refinery'' does not apply.
    (vi) If a pressure-assisted multi-point flare is used as a control
device for an emission point subject to the requirements in Table 7 to
this section, then the following conditions apply:
    (A) The owner or operator is not required to comply with the flare
tip velocity requirements in Sec.  63.670(d) and (k) of subpart CC;
    (B) The owner or operator must substitute ``800'' for each
occurrence of ``270'' in Sec.  63.670(e) of subpart CC;
    (C) The owner or operator must determine the 15-minute block
average NHVvg using only the direct calculation method specified in
Sec.  63.670(l)(5)(ii) of subpart CC;
    (D) Instead of complying with Sec.  63.670(b) and (g) of subpart
CC, if a pressure-assisted multi-point flare uses cross-lighting on a
stage of burners rather than having an individual pilot flame on each
burner, the owner or operator must operate each stage of the pressure-
assisted multi-point flare with a flame present at all times when
regulated material is routed to that stage of burners. Each stage of
burners that cross-lights in the pressure-assisted multi-point flare
must have at least two pilots with a continuously lit pilot flame
capable of igniting all regulated material that is routed to that stage
of burners. Each 15-minute block during which there is at least one
minute where no pilot flame is present on a stage of burners when
regulated material is routed to the flare is a deviation of the
standard. Deviations in different 15-minute blocks from the same event
are considered separate deviations. The pilot flame(s) on each stage of
burners that use cross-lighting must be continuously monitored by a
thermocouple or any other equivalent device used to detect the presence
of a flame;
    (E) The owner or operator of a pressure-assisted multi-point flare
must ensure that if a stage of burners on the flare uses cross-
lighting, that the distance between any two burners in series on that
stage is no more than 6 feet; and
    (F) The owner or operator of a pressure-assisted multi-point flare
must install and operate pressure monitor(s) on the main flare header,
as well as a valve position indicator monitoring system for each
staging valve to ensure that the flare operates within the proper range
of conditions as specified by the manufacturer. The pressure monitor
must meet the requirements in Table 13 of subpart CC of this part.
    (vii) If an owner or operator chooses to determine compositional
analysis for net heating value with a continuous process mass
spectrometer, the owner or operator must comply with the requirements
specified in paragraphs (e)(4)(vii)(A) through (G) of this section.
    (A) The owner or operator must meet the requirements in Sec.
63.671(e)(2). The owner or operator may augment the minimum list of
calibration gas components found in Sec.  63.671(e)(2) with compounds
found during a pre-survey or known to be in the gas through process
knowledge.
    (B) Calibration gas cylinders must be certified to an accuracy of 2
percent and traceable to National Institute of Standards and Technology
(NIST) standards.
    (C) For unknown gas components that have similar analytical mass
fragments to calibration compounds, the owner or operator may report
the unknowns as an increase in the overlapped calibration gas compound.
For unknown compounds that produce mass fragments that do not overlap
calibration compounds, the owner or operator may use the response
factor for the nearest molecular weight hydrocarbon in the calibration
mix to quantify the unknown component's NHVvg.
    (D) The owner or operator may use the response factor for n-pentane
to quantify any unknown components detected with a higher molecular
weight than n-pentane.
    (E) The owner or operator must perform an initial calibration to
identify mass fragment overlap and response factors for the target
compounds.
    (F) The owner or operator must meet applicable requirements in
Performance Specification 9 of 40 CFR part 60, appendix B, for
continuous monitoring system acceptance including, but not limited to,
performing an initial multi-point calibration check at three
concentrations following the procedure in Section 10.1 and performing
the periodic calibration requirements listed for gas chromatographs in
Table 13 of 40 CFR part 63, subpart CC, for the process mass
spectrometer. The owner or operator may use the alternative sampling
line temperature allowed under Net Heating Value by Gas Chromatograph
in Table 13 of 40 CFR part 63, subpart CC.
    (G) The average instrument calibration error (CE) for each
calibration compound at any calibration concentration must not differ
by more than 10 percent from the certified cylinder gas value. The CE
for each component in the calibration blend must be calculated using
the following equation:
[GRAPHIC] [TIFF OMITTED] TP09OC19.000

Where:

Cm = Average instrument response (ppm)
Ca = Certified cylinder gas value (ppm)

    (viii) An owner or operator using a gas chromatograph or mass
spectrometer for compositional analysis for net heating value may
choose to use the CE of NHVmeasured versus the cylinder tag
value NHV as the measure of agreement for daily calibration and
quarterly audits in lieu of determining the compound-specific CE. The
CE for NHV at any calibration level must not differ by more than 10
percent from the certified cylinder gas value. The CE for must be
calculated using the following equation:
[GRAPHIC] [TIFF OMITTED] TP09OC19.001

Where:

NHVmeasured = Average instrument response (Btu/scf)
NHVa = Certified cylinder gas value (Btu/scf)

    (ix) Instead of complying with Sec.  63.670(p) of subpart CC, the
owner or operator must keep the flare monitoring records specified in
Sec.  63.1109(e).
    (x) Instead of complying with Sec.  63.670(q) of subpart CC, the
owner or operator must comply with the reporting requirements specified
in Sec.  63.1110(d) and (e)(4).
    (xi) When determining compliance with the flare tip velocity and
combustion zone operating limits specified in Sec.  63.670(d) and (e),
the initial 15-minute block period starts with the 15-minute block that
includes a full 15 minutes of the flaring event.
    (5) Maintenance vents. Beginning no later than the compliance dates
specified in Sec.  63.1102(c), an owner or operator may designate a
process vent as a maintenance vent if the vent is only used as a result
of startup, shutdown, maintenance, or inspection of equipment where
equipment is emptied, depressurized, degassed, or placed into service.
The owner or operator must comply with the applicable requirements in
paragraphs (e)(5)(i) through (iii) of this section for each maintenance
vent, unless an extension is requested in accordance with the
provisions in Sec.  63.6(i) of subpart A.
    (i) Prior to venting to the atmosphere, remove process liquids from
the equipment as much as practical and depressurize the equipment to
either: A flare meeting the requirements specified in paragraph (e)(4)
of this section, or a non-flare control device meeting the requirements
specified in Sec.  63.982(c)(2) of subpart SS, until one of the
following conditions, as applicable, is met.
    (A) The vapor in the equipment served by the maintenance vent has a
lower explosive limit (LEL) of less than 10 percent.
    (B) If there is no ability to measure the LEL of the vapor in the
equipment based on the design of the equipment, the pressure in the
equipment served by the maintenance vent is reduced to 5 pounds per
square inch gauge (psig) or less. Upon opening the maintenance vent,
active purging of the equipment cannot be used until the LEL of the
vapors in the maintenance vent (or inside the equipment if the
maintenance is a hatch or similar type of opening) is less than 10
percent.
    (C) The equipment served by the maintenance vent contains less than
50 pounds of total volatile organic compounds (VOC).
    (D) If, after applying best practices to isolate and purge
equipment served by a maintenance vent, none of the applicable
criterion in paragraphs (e)(5)(i)(A) through (C) of this section can be
met prior to installing or removing a blind flange or similar equipment
blind, then the pressure in the equipment served by the maintenance
vent must be reduced to 2 psig or less before installing or removing
the equipment blind. During installation or removal of the equipment
blind, active purging of the equipment may be used provided the
equipment pressure at the location where purge gas is introduced
remains at 2 psig or less.
    (ii) Except for maintenance vents complying with the alternative in
paragraph (e)(5)(i)(C) of this section, the owner or operator must
determine the LEL or, if applicable, equipment pressure using process
instrumentation or portable measurement devices and follow procedures
for calibration and maintenance according to manufacturer's
specifications.
    (iii) For maintenance vents complying with the alternative in
paragraph (e)(5)(i)(C) of this section, the owner or operator must
determine mass of VOC in the equipment served by the maintenance vent
based on the equipment size and contents after considering any contents
drained or purged from the equipment. Equipment size may be determined
from equipment design specifications. Equipment contents may be
determined using process knowledge.
    (6) Bypass lines. Beginning on the compliance dates specified in
Sec.  63.1102(c), the use of a bypass line at any time on a closed vent
system to divert a vent stream to the atmosphere or to a control device
not meeting the requirements specified in Table 7 of this subpart is an
emissions standards violation. Equipment such as low leg drains and
equipment subject to the requirements specified in paragraph (f) of
Table 7 to Sec.  63.1103(e) are not subject to this paragraph (e)(6).
Open-ended valves or lines that use a cap, blind flange, plug, or
second valve and follow the requirements specified in Sec.  60.482-
6(a)(2), (b), and (c) are also not subject to this paragraph (e)(6). If
the owner or operator is subject to the bypass monitoring requirements
of Sec.  63.983(a)(3) of subpart SS, then the owner or operator must
continue to comply with the requirements in Sec.  63.983(a)(3) of
subpart SS and the recordkeeping and reporting requirements in
Sec. Sec.  63.998(d)(1)(ii) and 63.999(c)(2) of subpart SS, in addition
to paragraph (e)(9) of this section, the recordkeeping requirements
specified in Sec.  63.1109(g), and the reporting requirements specified
in Sec.  63.1110(e)(6).
    (7) Decoking operation standards for ethylene cracking furnaces.
Beginning no later than the compliance dates specified in Sec.
63.1102(c), the owner or operator must comply with paragraph (e)(7)(i)
of this section and also use at least two of the control measures
specified in paragraphs (e)(7)(ii) through (v) of this section to
minimize coke combustion emissions from the decoking of the radiant
tube(s) in each ethylene cracking furnace.
    (i) During normal operations, conduct daily inspections of the
firebox burners and repair all burners that are impinging on the
radiant tube(s) as soon as practical, but not later than 1 calendar day
after the flame impingement is found. An inspection may include, but is
not limited to: Visual inspection of the radiant tube(s) for localized
bright spots (this may be confirmed with a temperature gun), use of
luminescent powders injected into the burner to illuminate the flame
pattern, or identifying continued localized coke build-up that causes
short runtimes between decoking cycles. A repair may include, but is
not limited to: Taking the burner out of service, replacing the burner,
adjusting the alignment of the burner, adjusting burner configuration,
making burner air corrections, repairing a malfunction of the fuel
liquid removal equipment, or adding insulation around the radiant
tube(s).
    (ii) During decoking operations, continuously monitor (or use a gas
detection tube every hour to monitor) the CO2 concentration
at the radiant tube(s) outlet for indication that the coke combustion
in the ethylene cracking furnace radiant tube(s) is complete. The owner
or operator must immediately initiate procedures to stop the decoking
cycle once the CO2 concentration at the radiant tube(s)
outlet consistently reaches a level that indicates combustion of coke
inside the radiant tube(s) is slowing or stopping.
    (iii) During decoking operations, continuously monitor the
temperature at the radiant tube(s) outlet to ensure the coke combustion
occurring inside the radiant tube(s) is not so aggressive (i.e., too
hot) that it damages either the radiant tube(s) or ethylene cracking
furnace isolation valve(s). The owner or operator must immediately
initiate procedures to reduce the temperature at the radiant tube(s)
outlet once the temperature reaches a level that indicates combustion
of coke inside the radiant tube(s) is too aggressive.
    (iv) After decoking, but before returning the ethylene cracking
furnace back to normal operations, purge the

radiant tube(s) with steam and verify that all air is removed.
    (v) After decoking, but before returning the ethylene cracking
furnace back to normal operations, apply a coating material to the
interior of the radiant tube(s) to protect against coke formation
inside the radiant tube during normal operation.
    (8) Ethylene cracking furnace isolation valve inspections.
Beginning no later than the compliance dates specified in Sec.
63.1102(c), the owner or operator must conduct ethylene cracking
furnace isolation valve inspections as specified in paragraphs