Subpart LL—National Emission Standards for Hazardous Air Pollutants for Primary 

Aluminum Reduction Plants

§63.840 Applicability.

(a) Except as provided in paragraph (b) of this section, the requirements of this subpart apply to 

the owner or operator of each new or existing pitch storage tank, and new or existing potline, 

paste production plant, andor anode bake furnace associated with primary aluminum production 

and located at a major source as defined in §63.2.

(b) The requirements of this subpart do not apply to any existing anode bake furnace that is not 

located on the same site as a primary aluminum reduction plant. The owner or operator shall 

comply with the State MACT determination established by the applicable regulatory authority.

(c) An owner or operator of an affected facility (potroom group or anode bake furnace) under 

§60.190 of this chapter may elect to comply with either the requirements of §63.845 of this 

subpart or the requirements of subpart S of part 60 of this chapter.

§63.841 Incorporation by reference.

(a) The following material is incorporated by reference in the corresponding sections noted. This 

incorporation by reference was approved by the Director of the Federal Register on October 7, 

1997, in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. These materials are incorporated as 

they exist on the date of approval, and notice of any change in the materials will be published in 

the Federal Register. Revisions to “Industrial Ventilation: A Manual of Recommended Practice” 

(22nd ed.) are applicable only after publication of a document in the Federal Register to amend 

subpart LL to require use of the new information.

(1) Chapter 3, “Local Exhaust Hoods” and Chapter 5, “Exhaust System Design Procedure” of 

“Industrial Ventilation: A Manual of Recommended Practice,” American Conference of 

Governmental Industrial Hygienists, 22nd edition, 1995, IBR approved for §§63.843(b) and 

63.844(b); and

(2) ASTM D 2986–95A, Standard Practice for Evaluation of Air Assay Media by the 

Monodisperse DOP (Dioctyl Phthalate) Smoke Test, IBR approved for section 7.1.1 of Method 

315 in appendix A to this part; and.

(3) ASTM D3177-02 (2007) Standard Test Methods for Total Sulfur in the Analysis Sample of 

Coal and Coke.

(b) The materials incorporated by reference are available for at the National Archives and 

Records Administration (NARA), and at the Air and Radiation Docket Center, U.S. EPA, 1200 

Pennsylvania Ave., NW., Washington, DC. For information on the availability of this material at 

NARA, call 202–741–6030, or go to: 

http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. The 

materials also are available for purchase from one of the following addresses:
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(1) Customer Service Department, American Conference of Governmental Industrial Hygienists 

(ACGIH), 1330 Kemper Meadow Drive, Cincinnati, Ohio 45240, telephone number (513) 742–

2020; or

(2) American Society for Testing and Materials, 100 Bar Harbour Drive, West Conshohocken, 

Pennsylvania 19428, telephone number (610) 832–9500.

[62 FR 52407, Oct. 7, 1997, as amended at 69 FR 18803, Apr. 9, 2004]

§63.842 Definitions.

Terms used in this subpart are defined in the Clean Air Act as amended (the Act), in §63.2, or in 

this section as follows:

Affirmative defense means, in the context of an enforcement proceeding, a response or defense 

put forward by a defendant, regarding which the defendant has the burden of proof, and the 

merits of which are independently and objectively evaluated in a judicial or administrative 

proceeding.

Anode bake cycle means the period during which the regularly repeated sequence of loading, 

preheating, firing, cooling, and removing anodes from all sections within an anode bake furnace 

occurs one time.

Anode bake furnace means an oven in which the formed green anodes are baked for use in a 

prebake process. This definition includes multiple anode bake furnaces controlled by a common 

control device (bake furnaces controlled by a common control device are considered to be one 

source).

Center-worked prebake (CWPB) process means a method of primary aluminum reduction using 

the prebake process in which the alumina feed is added down the center of the reduction cell.

Center-worked prebake one (CWPB1) means all existing center-worked prebake potlines not 

defined as center-worked prebake two (CWPB2) or center-worked prebake three (CWPB3) 

potlines.

Center-worked prebake two (CWPB2) means all existing center-worked prebake potlines located 

at Alcoa in Rockdale, Texas; Kaiser Aluminum in Mead, Washington; Ormet Corporation in 

Hannibal, Ohio; Ravenswood Aluminum in Ravenswood, West Virginia; Reynolds Metals in 

Troutdale, Oregon; and Vanalco Aluminum in Vancouver, Washington.

Center-worked prebake three (CWPB3) means all existing center-worked prebake potlines that 

produce very high purity aluminum, have a wet scrubber for the primary control system, and are 

located at the NSA primary aluminum plant in Hawesville, Kentucky.
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Continuous parameter monitoring system means the total equipment that may be required to 

meet the data acquisition and availability requirements of this subpart, used to sample, condition 

(if applicable), analyze, and provide a record of process or control system parameters.

Horizontal stud Soderberg (HSS) process means a method of primary aluminum reduction using 

the Soderberg process in which the electrical current is introduced to the anode by steel rods 

(studs) inserted into the side of a monolithic anode.

Modified potroom group means an existing potroom group to which any physical change in, or 

change in the method of operation of, results in an increase in the amount of total fluoride 

emitted into the atmosphere by that potroom group.

Paste production plant means the processes whereby calcined petroleum coke, coal tar pitch 

(hard or liquid), and/or other materials are mixed, transferred, and formed into briquettes or paste 

for vertical stud Soderberg (VSS) and HSS processes or into green anodes for a prebake process. 

This definition includes all operations from initial mixing to final forming (i.e., briquettes, paste, 

green anodes) within the paste plant, including conveyors and units managing heated liquid 

pitch.

Pitch storage tank means any fixed roof tank that is used to store liquid pitch that is not part of 

the paste production plant.

Polycyclic organic matter (POM) means organic matter extractable by methylene chloride as 

determined by Method 315 in appendix A to this part or by an approved alternative method.

Potline means a single, discrete group of electrolytic reduction cells electrically connected in 

series, in which alumina is reduced to form aluminum.

Potroom means a building unit that houses a group of electrolytic cells in which aluminum is 

produced.

Potroom group means an uncontrolled potroom, a potroom that is controlled individually, or a 

group of potrooms or potroom segments ducted to a common control system.

Prebake process means a method of primary aluminum reduction that uses an anode that was 

baked in an anode bake furnace, which is introduced into the top of the reduction cell and 

consumed as part of the reduction process.

Primary aluminum reduction plant means any facility manufacturing aluminum by electrolytic 

reduction.

Primary control system means the equipment used to capture the gases and particulate matter 

evacuated directly from the reduction cell and the emission control device(s) used to remove 

pollutants prior to discharge of the cleaned gas to the atmosphere. A roof scrubber is not part of 

the primary control system.
4

Primary emissions means the emissions discharged from the primary control system.

Reconstructed potroom group means an existing potroom group for which the components are 

replaced to such an extent that the fixed capital cost of the new components exceeds 50 percent 

of the fixed capital cost that would be required to construct a comparable entirely new potroom 

group, and for which it is technologically and economically feasible to meet the applicable 

emission limits for total fluoride set forth in this subpart.

Reconstruction means the replacement of components of a source to such an extent that:

(1) All of the major components of the source are replaced (for example, the major components 

of a potline include the raw material handling system, reduction cells, superstructure, hooding, 

ductwork, etc.); and

(2) It is technologically and economically feasible for the reconstructed source to meet the 

standards for new sources established in this subpart.

Roof monitor means that portion of the roof of a potroom building where gases not captured at 

the cell exit from the potroom.

Secondary emissions means the fugitive emissions that are not captured and controlled by the 

primary control system and that escape through the roof monitor or through roof scrubbers.

Side-worked prebake (SWPB) process means a method of primary aluminum reduction using the 

prebake process, in which the alumina is added along the sides of the reduction cell.

Soderberg process means a method of primary aluminum reduction in which the anode paste 

mixture is baked in the reduction pot by the heat resulting from the electrolytic process.

Startup of an anode bake furnace means the process of initiating heating to the anode baking 

furnace where all sections of the furnace have previously been at ambient temperature. The 

startup or re-start of the furnace begins when the heating begins. The startup or re-start concludes 

at the start of the second anode bake cycle.

Total fluorides (TF) means elemental fluorine and all fluoride compounds as measured by 

Methods 13A or 13B in appendix A to part 60 of this chapter or by an approved alternative 

method.

Vertical stud Soderberg (VSS) process means a method of primary aluminum reduction using the 

Soderberg process, in which the electrical current is introduced to the anode by steel rods (studs) 

inserted into the top of a monolithic anode.

Vertical stud Soderberg one (VSS1) means all existing vertical stud Soderberg potlines located 

either at Northwest Aluminum in The Dalles, Oregon, or at Goldendale Aluminum in 

Goldendale, Washington.
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Vertical stud Soderberg two (VSS2) means all existing vertical stud Soderberg potlines located at 

Columbia Falls Aluminum in Columbia Falls, Montana.

[62 FR 52407, Oct. 7, 1997, as amended at 70 FR 66284, Nov. 2, 2005]

§63.843 Emission limits for existing sources.

(a) Potlines. The owner or operator shall not discharge or cause to be discharged into the 

atmosphere any emissions of TF or POM in excess of the applicable limits in paragraphs (a)(1) 

and (a)(2) of this section.

(1) TF limits. Emissions of TF shall not exceed:

(i) 0.95 kg/Mg (1.9 lb/ton) of aluminum produced for each CWPB1 potline;

(ii) 1.5 kg/Mg (3.0 lb/ton) of aluminum produced for each CWPB2 potline;

(iii) 1.25 kg/Mg (2.5 lb/ton) of aluminum produced for each CWPB3 potline;

(iv) 0.8 kg/Mg (1.6 lb/ton) of aluminum produced for each SWPB potline;

(v) 1.1 kg/Mg (2.2 lb/ton) of aluminum produced for each VSS1 potlineReserved;

(vi) 1.35 kg/Mg (2.7 lb/ton) of aluminum produced for each VSS2 potline; and

(vii) 1.35 kg/Mg (2.7 lb/ton) of aluminum produced for each HSS potline.

(2) POM limits. Emissions of POM shall not exceed:

(i) 2.351.5 kg/Mg (4.73.0 lb/ton) of aluminum produced for each HSS potline;

(ii) 1.2 kg/Mg (2.4 lb/ton) of aluminum produced for each VSS1 potlineReserved; and

(iii) 2.851.9 kg/Mg (3.85.7 lb/ton) of aluminum produced for each VSS2 potline;

(iv) 0.31 kg/Mg (0.62 lb/ton) of aluminum produced for each existing CWPB1 prebake potline;

(v) 0.65 kg/Mg (1.3 lb/ton) of aluminum produced for each existing CWPB2 prebake potline; 

(vi) 0.63 kg/Mg (1.26 lb/ton) of aluminum produced for each existing CWPB3 prebake potline;

and

(vii) 0.33 kg/Mg (0.65 lb/ton) of aluminum produced for each existing SWPB prebake potline.
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(3) Change in subcategory. Any potline, other than a reconstructed potline, that is changed such 

that its applicable subcategory also changes shall meet the applicable emission limit in this 

subpart for the original subcategory or the new subcategory, whichever is more stringent.

(b) Paste production plants. The owner or operator shall install, operate, and maintain equipment 

to capture and control POM emissions from each paste production plant.

(1) The emission capture system shall be installed and operated to meet the generally accepted 

engineering standards for minimum exhaust rates as published by the American Conference of 

Governmental Industrial Hygienists in Chapters 3 and 5 of “Industrial Ventilation: A Handbook 

of Recommended Practice” (incorporated by reference in §63.841 of this part); and

(2) Captured emissions shall be routed through a closed system to a dry coke scrubber; or

(3) The owner or operator may submit a written request for use of an alternative control device to 

the applicable regulatory authority for review and approval. The request shall contain 

information and data demonstrating that the alternative control device achieves POM emissions 

less than 0.011 lb/ton of paste for plants with continuous mixers or POM emissions less than 

0.024 lb/ton of paste for plants with batch mixers. The POM emission rate shall be determined 

by sampling using Method 315 in appendix A to this part.

(c) Anode bake furnaces. The owner or operator shall not discharge or cause to be discharged 

into the atmosphere any emissions of TF or POM in excess of the limits in paragraphs (c)(1) and 

(c)(2) of this section.

(1) TF limit. Emissions of TF shall not exceed 0.10 kg/Mg (0.20 lb/ton) of green anode; and

(2) POM limit. Emissions of POM shall not exceed 0.09 kg/Mg (0.18 lb/ton) of green anode.

(d) Pitch storage tanks. Each pitch storage tank shall be equipped with an emission control 

system designed and operated to reduce inlet emissions of POM by 95 percent or greater.

(e) COS limits. Emissions of COS must not exceed 3.9 lb/ton of aluminum produced. 

(f) At all times, the owner or operator must operate and maintain any affected source, including 

associated air pollution control equipment and monitoring equipment, in a manner consistent 

with safety and good air pollution control practices for minimizing emissions. Determination of 

whether such operation and maintenance procedures are being used will be based on information 

available to the Administrator which may include, but is not limited to, monitoring results, 

review of operation and maintenance procedures, review of operation and maintenance records, 

and inspection of the source.

[62 FR 52407, Oct. 7, 1997, as amended at 70 FR 66284, Nov. 2, 2005]

§63.844 Emission limits for new or reconstructed sources.
7

(a) Potlines. The owner or operator shall not discharge or cause to be discharged into the 

atmosphere any emissions of TF or POM in excess of the limits in paragraphs (a)(1) and (a)(2) of 

this section.

(1) TF limit. Emissions of TF shall not exceed 0.6 kg/Mg (1.2 lb/ton) of aluminum produced; and

(2) POM limit. Emissions of POM from Soderberg potlines shall not exceed 0.32 kg/Mg (0.63 

lb/ton) of aluminum produced.

(3) POM limit. Emissions of POM from prebake potlines must not exceed 0.31 kg/Mg (0.62 

lb/ton) of aluminum produced.

(b) Paste production plants. The owner or operator shall meet the requirements in §63.843(b) for 

existing paste production plants.

(c) Anode bake furnaces. The owner or operator shall not discharge or cause to be discharged 

into the atmosphere any emissions of TF or POM in excess of the limits in paragraphs (c)(1) and 

(c)(2) of this section.

(1) TF limit. Emissions of TF shall not exceed 0.01 kg/Mg (0.02 lb/ton) of green anode; and

(2) POM limit. Emissions of POM shall not exceed 0.025 kg/Mg (0.05 lb/ton) of green anode.

(d) Pitch storage tanks. Each pitch storage tank shall be equipped with an emission control 

system designed and operated to reduce inlet emissions of POM by 95 percent or greater.

(e) COS limits. Emissions of COS must not exceed 3.1 lb/ton of aluminum produced.

(f) At all times, the owner or operator must operate and maintain any affected source, including 

associated air pollution control equipment and monitoring equipment, in a manner consistent 

with safety and good air pollution control practices for minimizing emissions. Determination of 

whether such operation and maintenance procedures are being used will be based on information 

available to the Administrator which may include, but is not limited to, monitoring results, 

review of operation and maintenance procedures, review of operation and maintenance records, 

and inspection of the source.

§63.845 Incorporation of new source performance standards for potroom groups.

(a) Applicability. The provisions in paragraphs (a) through (i) of this section shall apply to any 

Soderberg, CWPB2, and CWPB3 potline that adds a new potroom group to an existing potline or 

that is associated with a potroom group that meets the definition of “modified potroom group” or 

“reconstructed potroom group.”

(1) The following shall not, by themselves, be considered to result in a potroom group 

modification:
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(i) Maintenance, repair, and replacement that the applicable regulatory authority determines to be 

routine for the potroom group;

(ii) An increase in production rate of an existing potroom group, if that increase can be 

accomplished without a capital expenditure on that potroom group;

(iii) An increase in the hours of operation;

(iv) Use of an alternative fuel or raw material if, prior to the effective date of this subpart, the 

existing potroom group was designed to accommodate that alternative use;

(v) The addition or use of any system or device whose primary function is the reduction of air 

pollutants, except when an emission control system is removed or is replaced by a system that 

the applicable regulatory authority determines to be less environmentally beneficial; and

(vi) The relocation or change in ownership of an existing potroom group.

(2) The provisions in paragraphs (a)(2)(i) through (a)(2)(iv) of this section apply when the 

applicable regulatory authority must determine if a potroom group meets the definition of 

reconstructed potroom group.

(i) “Fixed capital cost” means the capital needed to provide all the depreciable components.

(ii) If an owner or operator of an existing potroom group proposes to replace components, and 

the fixed capital cost of the new components exceeds 50 percent of the fixed capital cost that 

would be required to construct a comparable entirely new potroom group, he/she shall notify the 

applicable regulatory authority of the proposed replacements. The notice must be postmarked 60 

days (or as soon as practicable) before construction of the replacements is commenced and must 

include the following information:

(A) Name and address of the owner or operator;

(B) The location of the existing potroom group;

(C) A brief description of the existing potroom group and the components that are to be replaced;

(D) A description of the existing air pollution control equipment and the proposed air pollution 

control equipment;

(E) An estimate of the fixed capital cost of the replacements and of constructing a comparable 

entirely new potroom group;

(F) The estimated life of the existing potroom group after the replacements; and

(G) A discussion of any economic or technical limitations the potroom group may have in 

complying with the applicable standards of performance after the proposed replacements.
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(iii) The applicable regulatory authority will determine, within 30 days of the receipt of the 

notice required by paragraph (a)(2)(ii) of this section and any additional information he/she may 

reasonably require, whether the proposed replacement constitutes a reconstructed potroom group.

(iv) The applicable regulatory authority's determination under paragraph (a)(2)(iii) of this section 

shall be based on:

(A) The fixed capital cost of the replacements in comparison to the fixed capital cost that would 

be required to construct a comparable entirely new potroom group;

(B) The estimated life of the potroom group after the replacements compared to the life of a 

comparable entirely new potroom group;

(C) The extent to which the components being replaced cause or contribute to the emissions from 

the potroom group; and

(D) Any economic or technical limitations on compliance with applicable standards of 

performance that are inherent in the proposed replacements.

(b) Lower TF emission limit. The owner or operator shall calculate a lower TF emission limit for 

any potline associated with the modified potroom group, reconstructed potroom group, or new 

potroom group using the following equation:

L1=f1×LPG1+(1−f1)×LPL

Where:

L1=the lower TF emission limit in kg/Mg (lb/ton);

f1=the fraction of the potline's total aluminum production capacity that is contained within all 

modified potroom groups, reconstructed potroom groups, and new potroom groups;

LPG1=0.95 kg/Mg (1.9 lb/ton) for prebake potlines and 1.0 kg/Mg (2.0 lb/ton) for Soderberg 

potlines; and

LPL=the TF emission limit from §63.843(a)(1) for the appropriate potline subcategory that would 

have otherwise applied to the potline.

(c) Upper TF emission limit. The owner or operator shall calculate an upper TF emission limit 

for any potline associated with the modified potroom group, reconstructed potroom group, or 

new potroom group using the following equation:

L2=f1×LPG2+(1−f1)×LPL

Where:
10

L2=the upper TF emission limit in kg/Mg (lb/ton); and

LPG2=1.25 kg/Mg (2.5 lb/ton) for prebake potlines and 1.3 kg/Mg (2.6 lb/ton) for Soderberg 

potlines.

(d) Recalculation. The TF emission limits in paragraphs (b) and (c) of this section shall be 

recalculated each time a new potroom group is added to the potline and each time an additional 

potroom group meets the definition of “modified potroom group” or “reconstructed potroom 

group.”

(e) Emission limitation. The owner or operator shall not discharge or cause to be discharged into 

the atmosphere emissions of TF from any potline associated with the modified potroom group, 

reconstructed potroom group, or new potroom group that exceed the lower emission limit 

calculated in paragraph (b) of this section, except that emissions less than the upper limit 

calculated in paragraph (c) of this section will be considered in compliance if the owner or 

operator demonstrates that exemplary operation and maintenance procedures were used with 

respect to the emission control system and that proper control equipment was operating at the 

potline during the performance test.

(f) Report. Within 30 days of any performance test that reveals emissions that fall between the 

lower limit calculated in paragraph (b) of this section and the upper limit calculated in paragraph 

(c) of this section, the owner or operator shall submit to the applicable regulatory authority a 

report indicating whether all necessary control devices were online and operating properly during 

the performance test, describing the operating and maintenance procedures followed, and setting 

forth any explanation for the excess emissions.

(g) Procedures to determine TF emissions. The owner or operator shall determine TF emissions 

for the potline using the following procedures:

(1) Determine the emission rate of TF in kg/Mg (lb/ton) from sampling secondary emissions and 

the primary control system for all new potroom groups, modified potroom groups, and 

reconstructed potroom groups using the procedures, equations, and test methods in §§63.847, 

63.848, and 63.849.

(2) Determine the emission rate of TF in kg/Mg (lb/ton) from sampling secondary emissions and 

the primary control system for potroom groups or sections of potroom groups within the potline 

that are not new potroom groups, modified potroom groups, or reconstructed potroom groups 

according to paragraphs (g)(2)(i) or (g)(2)(ii) of this section.

(i) Determine the mass emission rate of TF in kg/Mg (lb/ton) from at least one potroom group 

within the potline that is not a new potroom group, modified potroom group, or reconstructed 

potroom group using the procedures, equations, and test methods in §§63.847, 63.848, and 

63.849, or

(ii) Use the results of the testing required by paragraph (g)(1) of this section to represent the 

entire potline based on a demonstration that the results are representative of the entire potline. 
11

Representativeness shall be based on showing that all of the potroom groups associated with the 

potline are substantially equivalent in terms of their structure, operability, type of emissions, 

volume of emissions, and concentration of emissions.

(3) Calculate the TF emissions for the potline in kg/Mg (lb/ton) based on the productionweighted average of the TF emission rates from paragraphs (g)(1) and (g)(2) of this section using 

the following equation:

E=f1×EPG1+(1-f1)×EPL

where:

E=the TF emission rate for the entire potline, kg/Mg (lb/ton);

f1=the fraction of the potline's total aluminum production rate that is contained within all 

modified potroom groups, reconstructed potroom groups, and new potroom groups;

EPG1=the TF emission rate from paragraph (g)(1) of this section for all modified potroom groups, 

reconstructed potroom groups, and new potroom groups, kg/Mg (lb/ton); and

EPL=the TF emission rate for the balance of the potline from paragraph (g)(2) of this section, 

kg/Mg (lb/ton).

Compliance is demonstrated when TF emissions for the potline meet the requirements in 

paragraph (e) of this section.

(4) As an alternative to sampling as required in paragraphs (g)(1) and (g)(2) of this section, the 

owner or operator may perform representative sampling of the entire potline subject to the 

approval of the applicable regulatory authority. Such sampling shall provide coverage by the 

sampling equipment of both the new, modified, or reconstructed potroom group and the balance 

of the potline. The coverage for the new, modified, or reconstructed potroom group must meet 

the criteria specified in the reference methods in §63.849. TF emissions shall be determined for 

the potline using the procedures, equations, and test methods in §§63.847, 63.848, and 63.849. 

Compliance is demonstrated when TF emissions for the potline meet the requirements in 

paragraph (e) of this section.

(h) Opacity. Except as provided in paragraph (i) of this section, the owner or operator shall not 

discharge or cause to be discharged into the atmosphere from the modified potroom group, 

reconstructed potroom group, or new potroom group any emissions of gases that exhibit 10 

percent opacity or greater.

(i) Alternative opacity limit. An alternative opacity limit may be established in place of the 

opacity limit in paragraph (h) of this section using the following procedures:

(1) If the regulatory authority finds that a potline is in compliance with the applicable TF 

standard for which performance tests are conducted in accordance with the methods and 
12

procedures in §63.849 but during the time such performance tests are being conducted fails to 

meet any applicable opacity standard, the regulatory authority shall notify and advise the owner 

or operator that he/she may petition the regulatory authority within 10 days of receipt of 

notification to make appropriate adjustment to the opacity standard.

(2) The regulatory authority will grant such a petition upon a demonstration by the owner or 

operator that the potroom group and associated air pollution control equipment were operated 

and maintained in a manner to minimize the opacity of emissions during the performance tests; 

that the performance tests were performed under the conditions established by the regulatory 

authority; and that the potroom group and associated air pollution control equipment were 

incapable of being adjusted or operated to meet the applicable opacity standard.

(3) As indicated by the performance and opacity tests, the regulatory authority will establish an 

opacity standard for any potroom group meeting the requirements in paragraphs (i)(1) and (i)(2) 

of this section such that the opacity standard could be met by the potroom group at all times 

during which the potline is meeting the TF emission limit.

(4) The alternative opacity limit established in paragraph (i)(3) of this section shall not be greater 

than 20 percent opacity.

§63.846 Emission averaging.

(a) General. The owner or operator of an existing potline or anode bake furnace in a State that

does not choose to exclude emission averaging in the approved operating permit program may 

demonstrate compliance by emission averaging according to the procedures in this section.

(b) Soderberg Potlines. The owner or operator may average TF emissions from potlines and 

demonstrate compliance with the limits in Table 1 of this subpart using the procedures in 

paragraphs (b)(1) and (b)(2) of this section. The owner or operator also may average POM 

emissions from potlines and demonstrate compliance with the limits in Table 2 of this subpart 

using the procedures in paragraphs (b)(1) and (b)(3) of this section.

(1) Monthly average emissions of TF and/or quarterly average emissions of POM shall not 

exceed the applicable emission limit in Table 1 of this subpart (for TF emissions) and/or Table 2 

of this subpart (for POM emissions). The emission rate shall be calculated based on the total 

emissions from all potlines over the period divided by the quantity of aluminum produced during 

the period, from all potlines comprising the averaging group.

(2) To determine compliance with the applicable emission limit in Table 1 of this subpart for TF 

emissions, the owner or operator shall determine the monthly average emissions (in lb/ton) from 

each potline from at least three runs per potline each month for TF secondary emissions using the 

procedures and methods in §§63.847 and 63.849. The owner or operator shall combine the 

results of secondary TF monthly average emissions with the TF results for the primary control 

system and divide total emissions by total aluminum production.
13

(3) To determine compliance with the applicable emission limit in Table 2 of this subpart for 

POM emissions, the owner or operator shall determine the quarterly average emissions (in 

lb/ton) from each potline from at least one run each month for POM emissions using the 

procedures and methods in §§63.847 and 63.849. The owner or operator shall combine the 

results of secondary POM quarterly average emissions with the POM results for the primary 

control system and divide total emissions by total aluminum production.

(c) Anode bake furnaces. The owner or operator may average TF emissions from anode bake 

furnaces and demonstrate compliance with the limits in Table 3 of this subpart using the 

procedures in paragraphs (c)(1) and (c)(2) of this section. The owner or operator also may 

average POM emissions from anode bake furnaces and demonstrate compliance with the limits 

in Table 3 of this subpart using the procedures in paragraphs (c)(1) and (c)(2) of this section.

(1) Annual emissions of TF and/or POM from a given number of anode bake furnaces making up 

each averaging group shall not exceed the applicable emission limit in Table 3 of this subpart in 

any one year; and

(2) To determine compliance with the applicable emission limit in Table 3 of this subpart for 

anode bake furnaces, the owner or operator shall determine TF and/or POM emissions from the 

control device for each furnace at least once a year using the procedures and methods in 

§§63.847 and 63.849.

(d) Implementation plan. The owner or operator shall develop and submit an implementation 

plan for emission averaging to the applicable regulatory authority for review and approval 

according to the following procedures and requirements:

(1) Deadlines. The owner or operator must submit the implementation plan no later than 6 

months before the date that the facility intends to comply with the emission averaging limits.

(2) Contents. The owner or operator shall include the following information in the 

implementation plan or in the application for an operating permit for all emission sources to be 

included in an emissions average:

(i) The identification of all emission sources (potlines or anode bake furnaces) in the average;

(ii) The assigned TF or POM emission limit for each averaging group of potlines or anode bake 

furnaces;

(iii) The specific control technology or pollution prevention measure to be used for each 

emission source in the averaging group and the date of its installation or application. If the 

pollution prevention measure reduces or eliminates emissions from multiple sources, the owner 

or operator must identify each source;

(iv) The test plan for the measurement of TF or POM emissions in accordance with the 

requirements in §63.847(b) and (k);
14

(v) The operating parameters to be monitored for each control system or device and a description 

of how the operating limits will be determined;

(vi) If the owner or operator requests to monitor an alternative operating parameter pursuant to 

§63.848(l):

(A) A description of the parameter(s) to be monitored and an explanation of the criteria used to 

select the parameter(s); and

(B) A description of the methods and procedures that will be used to demonstrate that the 

parameter indicates proper operation of the control device; the frequency and content of 

monitoring, reporting, and recordkeeping requirements; and a demonstration, to the satisfaction 

of the applicable regulatory authority, that the proposed monitoring frequency is sufficient to 

represent control device operating conditions; and

(vii) A demonstration that compliance with each of the applicable emission limit(s) will be 

achieved under representative operating conditions.

(3) Approval criteria. Upon receipt, the regulatory authority shall review and approve or 

disapprove the plan or permit application according to the following criteria:

(i) Whether the content of the plan includes all of the information specified in paragraph (d)(2) of 

this section; and

(ii) Whether the plan or permit application presents sufficient information to determine that 

compliance will be achieved and maintained.

(4) Prohibitions. The applicable regulatory authority shall not approve an implementation plan or 

permit application containing any of the following provisions:

(i) Any averaging between emissions of differing pollutants or between differing sources. 

Emission averaging shall not be allowed between TF and POM, and emission averaging shall not 

be allowed between potlines and bake furnaces;

(ii) The inclusion of any emission source other than an existing potline or existing anode bake 

furnace subject to the same operating permit; or or the inclusion of any potline or anode bake 

plant not subject to the same operating permit;

(iii) The inclusion of any potline or anode bake furnace while it is shut down, in the emissions 

calculations.; or

(iv) Reserved.The inclusion of any periods of startup, shutdown, or malfunction, as described in 

the startup, shutdown, and malfunction plan required by §63.850(c), in the emission calculations.

(5) Term. Following review, the applicable regulatory authority shall approve the plan or permit 

application, request changes, or request additional information. Once the applicable regulatory 
15

authority receives any additional information requested, the applicable regulatory authority shall 

approve or disapprove the plan or permit application within 120 days.

(i) The applicable regulatory authority shall approve the plan for the term of the operating 

permit;

(ii) To revise the plan prior to the end of the permit term, the owner or operator shall submit a 

request to the applicable regulatory authority; and

(iii) The owner or operator may submit a request to the applicable regulatory authority to 

implement emission averaging after the applicable compliance date.

(6) Operation. While operating under an approved implementation plan, the owner or operator 

shall monitor the operating parameters of each control system, keep records, and submit periodic 

reports as required for each source subject to this subpart.

(e) TF emissions from Prebake Potlines. The owner or operator may average TF emissions from 

potlines and demonstrate compliance with the limits in Table 1 of this subpart using the 

procedures in paragraphs (e)(1) and (e)(2) of this section.

(1) Monthly average emissions of TF must not exceed the applicable emission limit in Table 1 

of this subpart. The emission rate must be calculated based on the total emissions from all 

potlines over the period divided by the quantity of aluminum produced during the period, from 

all potlines comprising the averaging group.

(2) To determine compliance with the applicable emission limit in Table 1 of this subpart for TF 

emissions, the owner or operator must determine the monthly average emissions (in lb/ton) from 

each potline from at least three runs per potline each month for TF secondary emissions using the 

procedures and methods in Sections 63.847 and 63.849. The owner or operator must combine the 

results of secondary TF monthly average emissions with the TF results for the primary control 

system and divide total emissions by total aluminum production.

(f) POM Emissions from Prebake Potlines. The owner or operator also may average POM 

emissions from potlines and demonstrate compliance with the limits in Table 2 of this subpart

using the procedures in paragraphs (f)(1) and (f)(2) of this section.

(1) Average emissions of POM for each compliance demonstration period, must not exceed the 

applicable emission limit in Table 2 of this subpart. The emission rate must be calculated based 

on the total emissions from all potlines divided by the quantity of aluminum produced during the 

period, from all potlines comprising the averaging group.

(2) To determine compliance with the applicable emission limit in Table 2 of this subpart for 

POM emissions, the owner or operator must determine the emissions (in lb/ton) from each 

potline using the procedures and methods in Sections 63.847 and 63.849. The owner or operator 

must combine the results of measured or calculated secondary POM emissions with the POM 

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emissions from the primary control system and divide total emissions by total aluminum 

production.

§63.847 Compliance provisions.

(a) Compliance Dates. The owner operator of a primary aluminum reduction plant must comply 

with the requirements of this subpart by the applicable compliance date in paragraph (a)(1), 

(a)(2) or (a)(3) of this section:

(a) (1) Except as noted in paragraph (2) of this section, the compliance date for an owner or 

operator of an existing plant or source subject to the provisions of this subpart is October 7, 

1999.

(2) The compliance dates for existing plants and sources are:

(i) [Insert date 90-days after date of publication of final rule] for Soderberg potlines subject to 

emission limits in §§63.843(a)(2)(i) and (iii) which became effective [insert date of publication 

of final rule].

(ii) [Insert date 3 years after date of publication of final rule] for prebake potlines subject to 

emission limits in §63.843(a)(2)(iv) through (vii) and §63.848(n) which became effective [insert 

date of publication of final rule].

(iii) [Insert date 3 years after date of publication of final rule] for potlines subject to the work 

practice standards in §63.854 which became effective [insert date of publication of final rule].

(iv) [Insert date 3 years after date of publication of final rule] for anode bake furnaces subject to 

the startup practices in §63.854(m) which became effective [insert date of publication of final 

rule]. 

(v) [Insert date 3 years after date of publication of final rule] for compliance with the pitch 

storage tank POM limit provisions of §63.843(d) and the COS emission limit provisions of 

§63.843(e) and §63.844(e).

(vii) [Insert date of publication of final rule] for the malfunction provisions of §§63.850(d)(2) 

and (e)(4)(xvi) and (xvii), the affirmative defense provisions of §63.855, and the electronic 

reporting provisions of §§63.850(c) and (f).

(3) Reserved. Compliance dates . The owner or operator of a primary aluminum plant must 

comply with the requirements of this subpart by:

(1) October 7, 1999, for an owner or operator of an existing plant or source;

(2) October 9, 2000, for an existing source, provided the owner or operator demonstrates to the 

satisfaction of the applicable regulatory authority that additional time is needed to install or 

modify the emission control equipment;

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17

(3) October 8, 2001, for an existing source that is granted an extension by the regulatory 

authority under section 112(i)(3)(B) of the Act; or

(4) Upon startup, for an owner or operator of a new or reconstructed source.

(b) Test plan for TF from all anode bake furnaces and potlines and POM from Soderberg 

potlines. The owner or operator shall prepare a site-specific test plan prior to the initial 

performance test according to the requirements of Sec. 63.7(c) of this part. The test plan must 

include procedures for conducting the initial performance test and for subsequent performance 

tests required in Sec. 63.848 for emission monitoring. In addition to the information required by 

Sec. 63.7, the test plan shall include. The owner or operator shall prepare a site-specific test plan 

prior to the initial performance test according to the requirements of §63.7(c) of this part. The 

test plan must include procedures for conducting the initial performance test and for subsequent 

performance tests required in §63.848 for emission monitoring. In addition to the information 

required by §63.7, the test plan shall include:

(1) Procedures to ensure a minimum of three runs are performed annually for the primary control 

system for each source;

(2) For a source with a single control device exhausted through multiple stacks, procedures to 

ensure that at least three runs are performed annually by a representative sample of the stacks 

satisfactory to the applicable regulatory authority;

(3) For multiple control devices on a single source, procedures to ensure that at least one run is 

performed annually for each control device by a representative sample of the stacks satisfactory 

to the applicable regulatory authority;

(4) Procedures for sampling single stacks associated with multiple anode bake furnaces;

(5) For plants with roof scrubbers, procedures for rotating sampling among the scrubbers or other 

procedures to obtain representative samples as approved by the applicable regulatory authority;

(6) For a VSS1 potline, procedures to ensure that one fan (or one scrubber) per potline is 

sampled for each runReserved;

(7) For a SWPB potline, procedures to ensure that the average of the sampling results for two 

fans (or two scrubbers) per potline is used for each run; and

(8) Procedures for establishing the frequency of testing to ensure that at least one run is 

performed before the 15th of the month, at least one run is performed after the 15th of the month, 

and that there are at least 6 days between two of the runs during the month, or that secondary 

emissions are measured according to an alternate schedule satisfactory to the applicable 

regulatory authority.

(c) Performance test dates . Following approval of the site-specific test plan, the owner or 

operator must conduct a performance test to demonstrate initial compliance according to the 
18

procedures in paragraph (d) of this section. If a performance test has been conducted on the 

primary control system for potlines or for the anode bake furnace within the 12 months prior to 

the compliance date, the results of that performance test may be used to demonstrate initial 

compliance. The owner or operator must conduct the performance test:

(1) During the first month following the compliance date for an existing potline (or potroom 

group), or anode bake furnace or pitch storage tank;

(2) By the 180th day following startup for a potline or potroom group for which the owner or 

operator elects to conduct an initial performance test. The 180-day period starts when the first 

pot in a potline or potroom group is energized.By the date determined according to the 

requirements in paragraph (c)(2)(i), (ii), or (iii) of this section for a new or reconstructed potline, 

anode bake furnace, or pitch storage tank (for which the owner or operator elects to conduct an 

initial performance test):

(i) By the 180th day following startup for a potline or potroom group. The 180-day period starts 

when the first pot in a potline or potroom group is energizedReserved.

(ii) By the 45th day from the start of the second anode bake cycle (but no later than the 180th day 

from the startup of the anode bake furnace)Reserved.

(iii) By the 30th day following startup for a pitch storage tank. The 30-day period starts when the 

tank is first used to store pitchReserved.

(3) By the 180th day following startup for a potline or potroom group that was shut down at the 

time compliance would have otherwise been required and is subsequently restarted. The 180-day 

period starts when the first pot in a potline or potroom group is energized.By the date determined 

according to the requirements in paragraph (c)(3)(i) or (ii) of this section for an existing potline 

or anode bake furnace that was shut down at the time compliance would have otherwise been 

required and is subsequently restarted:

(i) By the 180th day following startup for a potline or potroom group. The 180-day period starts 

when the first pot in a potline or potroom group is energizedReserved.

(ii) By the 45th day from the start of the second anode bake cycle (but no later than the 180th day 

from the startup of the anode bake furnace)Reserved.

(d) Performance test requirements. The initial performance test and all subsequent performance 

tests shall be conducted in accordance with the requirements of the general provisions in subpart 

A of this part, the approved test plan, and the procedures in this section. Performance tests must

be conducted under such conditions as the Administrator specifies to the owner or operator based 

on representative performance of the affected source for the period being tested. Upon request, 

the owner or operator must make available to the Administrator such records as may be 

necessary to determine the conditions of performance tests.
19

(1) TF emissions from potlines. For each potline, the owner or operator shall measure and record 

the emission rate of TF exiting the outlet of the primary control system for each potline and the 

rate of secondary emissions exiting through each roof monitor, or for a plant with roof scrubbers, 

exiting through the scrubbers. Using the equation in paragraph (e)(1) of this section, the owner or 

operator shall compute and record the average of at least three runs each month for secondary 

emissions and at least three runs each year for the primary control system to determine 

compliance with the applicable emission limit. Compliance is demonstrated when the emission 

rate of TF is equal to or less than the applicable emission limit in §63.843, §63.844, or §63.846.

(2) POM emissions from Soderberg potlines. For each Soderberg (HSS, VSS1, and VSS2) 

potline, the owner or operator shall must measure and record the emission rate of POM exiting 

the primary emission control system and the rate of secondary emissions exiting through each 

roof monitor, or for a plant with roof scrubbers, exiting through the scrubbers. Using the 

equation in paragraph (e)(2) of this section, the owner or operator shall must compute and record 

the average of at least three runs each quarter (one run per month) for secondary emissions and at 

least three runs each year for the primary control system to determine compliance with the 

applicable emission limit. Compliance is demonstrated when the emission rate of POM is equal 

to or less than the applicable emission limit in §63.843, §63.844, or §63.846.

(3) Previous control device tests. If the owner or operator has performed more than one test of 

primary emission control device(s) for a potline or for a bake furnace during the previous 

consecutive 12 months, the average of all runs performed in the previous 12-month period shall 

be used to determine the contribution from the primary emission control system.

(4) TF and POM emissions from anode bake furnaces. For each anode bake furnace, the owner 

or operator shall measure and record the emission rate of TF and POM exiting the exhaust 

stacks(s) of the primary emission control system for each anode bake furnace. Using the 

equations in paragraphs (e)(3) and (e)(4) of this section, the owner or operator shall compute and 

record the average of at least three runs each year to determine compliance with the applicable 

emission limits for TF and POM. Compliance is demonstrated when the emission rates of TF and 

POM are equal to or less than the applicable TF and POM emission limits in §63.843, §63.844, 

or §63.846.

(5) POM emission from prebake potlines. For each prebake potline, the owner or operator shall 

measure and record the emission rate of POM exiting the primary emission control system. The 

owner or operator shall compute and record the average of at least three runs every five years. 

For each prebake potline for which the owner or operator chooses to demonstrate compliance 

using the provisions of Sec. 63.847(e)(2), the owner or operator shall measure and record the 

emission rate of secondary emissions exiting through each roof monitor, or for a plant with roof 

scrubbers, exiting through the scrubbers. The owner or operator shall compute and record the 

average of at least three runs every five years for secondary emissions. The owner or operator 

shall calculate POM emissions in accordance with Sec. 847(e)(2) or (8). Compliance is 

demonstrated when the emission rate of POM is equal to or less than the applicable emission 

limit in Sec. 63.843, Sec. 63.844, or Sec. 63.846.
20

(e) Equations. The owner or operator shall determine compliance with the applicable TF and 

POM emission limits using the following equations and procedures:

(1) Compute the emission rate (Ep) of TF from each potline using Equation 1:

Where:

Ep=emission rate of TF from a potline, kg/Mg (lb/ton);

Cs1=concentration of TF from the primary control system, mg/dscm (mg/dscf);

Qsd=volumetric flow rate of effluent gas corresponding to the appropriate subscript location, 

dscm/hr (dscf/hr);

Cs2=concentration of TF as measured for roof monitor emissions, mg/dscm (mg/dscf);

P=aluminum production rate, Mg/hr (ton/hr);

K=conversion factor, 106 mg/kg (453,600 mg/lb);

1= subscript for primary control system effluent gas; and

2= subscript for secondary control system or roof monitor effluent gas.

(2) Compute the emission rate of POM from each Soderberg potline, and from those prebake 

potlines for which the owner or operator chooses to measure secondary emissions, using 

Equation 1,

Where:

Ep = emission rate of POM from the potline, kg/mg (lb/ton); and

Cs = concentration of POM, mg/dscm (mg/dscf). POM emission data collected during the 

installation and startup of a cathode must not be included in Cs. Compute the emission rate of 

POM from each potline using Equation 1,

Where:

Ep= emission rate of POM from the potline, kg/mg (lb/ton); and

Cs= concentration of POM, mg/dscm (mg/dscf). POM emission data collected during the 

installation and startup of a cathode shall not be included in Cs.
21

(3) Compute the emission rate (Eb) of TF from each anode bake furnace using Equation 2,

Where:

Eb= emission rate of TF, kg/mg (lb/ton) of green anodes produced;

Cs= concentration of TF, mg/dscm (mg/dscf);

Qsd= volumetric flow rate of effluent gas, dscm/hr (dscf/hr);

Pb= quantity of green anode material placed in the furnace, mg/hr (ton/hr); and

K = conversion factor, 106 mg/kg (453,600 mg/lb).

(4) Compute the emission rate of POM from each anode bake furnace using Equation 2,

Where:

Cs= concentration of POM, mg/dscm (mg/dscf).

(5) Determine the weight of the aluminum tapped from the potline and the weight of the green 

anode material placed in the anode bake furnace using the monitoring devices required in 

§63.848(j).

(6) Determine the aluminum production rate (P) by dividing the number of hours in the calendar 

month into the weight of aluminum tapped from the potline during the calendar month that 

includes the three runs of a performance test.

(7) Determine the rate of green anode material introduced into the furnace by dividing the 

number of operating hours in the calendar month into the weight of green anode material used 

during the calendar month in which the performance test was conducted.

(8) Compute the rate of POM from each prebake potline for which the owner or operator does 

not choose to determine the measure the secondary emissions using Equation 3:

 (Equation 3)

Where:

Epp = emission rate of POM from a potline, kg/Mg (lb/ton)
22

Cpp1 = concentration of POM from the primary control system, mg/dscm (mg/dscf)

Q1 = volumetric flow rate of effluent gas from the primary control system dscm/hr (dscf/hr)

CpF2 = concentration of TF from the secondary control system or roof monitor, mg/dscm 

(mg/dscf)

CpF1 = concentration of TF from the primary control system, mg/dscm (mg/dscf)

Q2 = volumetric flow rate of effluent gas from the secondary control system or roof monitor, 

dscm/hr (dscf/hr).

(f) Paste production plants. Initial compliance with the standards for existing and new paste 

production plants in §§63.843(b) and 63.844(b) will be demonstrated through site inspection(s) 

and review of site records by the applicable regulatory authority.

(g) Pitch storage tanks. The owner or operator must demonstrate initial compliance with the 

standard for pitch storage tanks in §63.843(d) and §63.844(d) by preparing a design evaluation or 

by conducting a performance test. The owner or operator shall submit for approval by the 

regulatory authority the information specified in paragraph (g)(1) of this section, along with the 

information specified in paragraph (g)(2) of this section where a design evaluation is performed 

or the information specified in paragraph (g)(3) of this section where a performance test is 

conductedThe owner or operator shall demonstrate initial compliance with the standard for pitch 

storage tanks in §63.844(d) by preparing a design evaluation or by conducting a performance 

test. The owner or operator shall submit for approval by the regulatory authority the information 

specified in paragraph (g)(1) of this section, along with the information specified in paragraph 

(g)(2) of this section where a design evaluation is performed or the information specified in 

paragraph (g)(3) of this section where a performance test is conducted.

(1) A description of the parameters to be monitored to ensure that the control device is being 

properly operated and maintained, an explanation of the criteria used for selection of that 

parameter (or parameters), and the frequency with which monitoring will be performed; and

(2) Where a design evaluation is performed, documentation demonstrating that the control device 

used achieves the required control efficiency during reasonably expected maximum filling rate. 

The documentation shall include a description of the gas stream that enters the control device, 

including flow and POM content under varying liquid level conditions, and the information 

specified in paragraphs (g)(2)(i) through (g)(2)(vi) of this section, as applicable.

(i) If the control device receives vapors, gases, or liquids, other than fuels, from emission points 

other than pitch storage tanks, the efficiency demonstration is to include consideration of all 

vapors, gases, and liquids, other than fuels, received by the control device;

(ii) If an enclosed combustion device with a minimum residence time of 0.5 seconds and a 

minimum temperature of 760 °C (1,400 °F) is used to meet the emission reduction requirement 
23

specified in §83.844(d), documentation that those conditions exist is sufficient to meet the 

requirements of §83.844(d);

(iii) Except as provided in paragraph (g)(2)(ii) of this section, for thermal incinerators, the design 

evaluation shall include the autoignition temperature of the organic HAP, the flow rate of the 

organic HAP emission stream, the combustion temperature, and the residence time at the 

combustion temperature;

(iv) If the pitch storage tank is vented to the emission control system installed for control of 

emissions from the paste production plant pursuant to §63.843(b), documentation of compliance 

with the requirements of §63.843(b) is sufficient to meet the requirements of §63.844(d);

(v) For carbon adsorbers, the design evaluation shall include the affinity of the organic vapors for 

carbon, the amount of carbon in each bed, the number of beds, the humidity of the feed gases, the 

temperature of the feed gases, the flow rate of the organic HAP emission stream, and if 

applicable, the desorption schedule, the regeneration stream pressure or temperature, and the 

flow rate of the regeneration stream. For vacuum desorption, the pressure drop shall be included; 

and

(vi) For condensers, the design evaluation shall include the final temperature of the organic HAP 

vapors, the type of condenser, and the design flow rate of the organic HAP emission stream.

(3) If a performance test is conducted, the owner or operator shall determine the control 

efficiency for POM during tank loading using Method 315 in appendix A to this part. The owner 

or operator shall include the following information:

(i) Identification of the pitch storage tank and control device for which the performance test will 

be submitted; and

(ii) Identification of the emission point(s) that share the control device with the pitch storage tank 

and for which the performance test will be conducted.

(h) Selection of monitoring parameters. The owner or operator shall determine the operating 

limits and monitoring frequency for each control device that is to be monitored as required in 

§63.848(f).

(1) For potlines and anode bake furnaces, the owner or operator shall determine upper and/or 

lower operating limits, as appropriate, for each monitoring device for the emission control 

system from the values recorded during each of the runs performed during the initial 

performance test and from historical data from previous performance tests conducted by the 

methods specified in this subpart.

(2) For a paste production plant, the owner or operator shall specify and provide the basis or 

rationale for selecting parameters to be monitored and the associated operating limits for the 

emission control device.
24

(3) The owner or operator may redetermine the upper and/or lower operating limits, as 

appropriate, based on historical data or other information and submit an application to the 

applicable regulatory authority to change the applicable limit(s). The redetermined limits shall 

become effective upon approval by the applicable regulatory authority.

(i) Reserved.

(j) COS Emissions. The owner operator of each plant must calculate the facility wide emission 

rate of COS for each calendar month of operation using the following equation:

Where:

ECOS = the facility wide emission rate of COS during the calendar month in pounds per ton of 

aluminum produced;

K = factor accounting for molecular weights and conversion of sulfur to carbonyl sulfide = 234;

Y = the tons of anode used at the facility during the calendar month;

Z = the tons of aluminum produced at the facility during the calendar month; and

%S = the weighted average sulfur content of the anode coke utilized in the production of 

aluminum during the calendar month (e.g., if the weighted average sulfur content of the anode 

coke utilized during the calendar month was 2.5%, then %S = 0.025).

Compliance is demonstrated if the calculated value of ECOS is less than the applicable standard 

for COS emissions in §§63.843(e) and 63.844(e).

(k) Test plan POM from prebake potlines. The owner or operator must prepare a site-specific test 

plan prior to the initial performance test according to the requirements of §63.7(c) of this part. 

The test plan must include procedures for conducting the initial performance test and for 

subsequent performance tests required in §63.848 for emission monitoring. In addition to the 

information required by §63.7 the test plan shall include:

(1) Procedures to ensure a minimum of three runs are performed for the primary control system 

for each source;

(2) For a source with a single control device exhausted through multiple stacks, procedures to 

ensure that at least three runs are performed by a representative sample of the stacks satisfactory 

to the applicable regulatory authority;

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(3) For multiple control devices on a single source, procedures to ensure that at least one run is 

performed for each control device by a representative sample of the stacks satisfactory to the 

applicable regulatory authority;

(4) For plants with roof scrubbers, procedures for rotating sampling among the scrubbers or other 

procedures to obtain representative samples as approved by the applicable regulatory authority.

(l) Potlines and anode bake furnaces. The owner or operator shall develop a written plan as 

described in §63.854 that contains specific procedures to be followed during startup periods of 

potline(s). Compliance with the applicable standards in §63.854 will be demonstrated through 

site inspection(s) and review of site records by the applicable regulatory authority.

(m) Anode bake furnaces. If you own or operate a new or existing primary aluminum reduction 

affected source, you must develop a written startup plan as described in paragraphs (m)(1) 

through (4) of this section. Compliance with the startup plan will be demonstrated through site 

inspection(s) and review of site records by the applicable regulatory authority. The written 

startup plan must contain specific procedures to be followed during startup periods of anode bake 

furnaces, including the following:

(1) A requirement to develop an anode bake furnace startup schedule prior to startup of the first 

anode bake furnace.

(2) Records of time, date, duration and any nonroutine actions taken during startup of the 

furnaces.

(3) A requirement that the associated emission control system should be operating within normal 

parametric limits prior to startup of the first anode bake furnace.

(4) A requirement to shut down the anode bake furnaces immediately if the associated emission 

control system is off line at any time during startup.

[62 FR 52407, Oct. 7, 1997, as amended at 70 FR 66284, Nov. 2, 2005]

§63.848 Emission monitoring requirements.

(a) TF emissions from potlines. Using the procedures in §63.847 and in the approved test plan, 

the owner or operator shall monitor emissions of TF from each potline by conducting monthly 

performance tests. The owner or operator shall compute and record the monthly average from at 

least three runs for secondary emissions and the previous 12-month average of all runs for the 

primary control system to determine compliance with the applicable emission limit. The owner 

or operator must include all valid runs in the monthly average. The duration of each run for 

secondary emissions must represent a complete operating cycle.

(b) POM emissions from Soderberg potlines. Using the procedures in Sec. 63.847 and in the 

approved test plan, the owner or operator shall monitor emissions of POM from each Soderberg 

(HSS and VSS2) potline every three months. The owner or operator shall compute and record the 

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quarterly (3-month) average from at least one run per month for secondary emissions and the 

previous 12-month average of all runs for the primary control systems to determine compliance 

with the applicable emission limit. The owner or operator must include all valid runs in the 

quarterly (3-month) average. The duration of each run for secondary emissions must represent a 

complete operating cycle. The primary control system must be sampled over an 8-hour period, 

unless site-specific factors dictate an alternative sampling time subject to the approval of the 

regulatory authorityUsing the procedures in §63.847 and in the approved test plan, the owner or 

operator shall monitor emissions of POM from each Soderberg (HSS, VSS1, and VSS2) potline 

every three months. The owner or operator shall compute and record the quarterly (3-month) 

average from at least one run per month for secondary emissions and the previous 12-month 

average of all runs for the primary control systems to determine compliance with the applicable 

emission limit. The owner or operator must include all valid runs in the quarterly (3-month) 

average. The duration of each run for secondary emissions must represent a complete operating 

cycle. The primary control system must be sampled over an 8-hour period, unless site-specific 

factors dictate an alternative sampling time subject to the approval of the regulatory authority.

(c) TF and POM emissions from anode bake furnaces. Using the procedures in §63.847 and in 

the approved test plan, the owner or operator shall monitor TF and POM emissions from each 

anode bake furnace on an annual basis. The owner or operator shall compute and record the 

annual average of TF and POM emissions from at least three runs to determine compliance with 

the applicable emission limits. The owner or operator must include all valid runs in the annual 

average.

(d) Similar potlines. As an alternative to monthly monitoring of TF or POM secondary emissions 

from each potline using the test methods in §63.849, the owner or operator may perform monthly 

monitoring of TF or POM secondary emissions from one potline using the test methods in 

§§63.849 (a) or (b) to represent the performance of similar potline(s). The similar potline(s) shall 

be monitored using an alternative method that meets the requirements of paragraphs (d)(1) 

through (d)(7) of this section. Two or more potlines are similar if the owner or operator 

demonstrates that their structure, operability, type of emissions, volume of emissions, and 

concentration of emissions are substantially equivalent.

(1) To demonstrate (to the satisfaction of the regulatory authority) that the level of emission 

control performance is the same or better, the owner or operator shall perform an emission test 

using an alternative monitoring procedure for the similar potline simultaneously with an 

emission test using the applicable test methods. The results of the emission test using the 

applicable test methods must be in compliance with the applicable emission limit for existing or 

new potlines in §63.843 or §63.844. An alternative method:

(i) For TF emissions, must account for or include gaseous fluoride and cannot be based on 

measurement of particulate matter or particulate fluoride alone; and

(ii) For TF and POM emissions, must meet or exceed Method 14 criteria.

(2) An HF continuous emission monitoring system is an approved alternative for the monitoring 

of TF secondary emissions.
27

(3) An owner or operator electing to use an alternative monitoring procedure shall establish an 

alternative emission limit based on at least nine simultaneous runs using the applicable test 

methods and the alternative monitoring method. All runs must represent a full process cycle.

(4) The owner or operator shall derive an alternative emission limit for the HF continuous 

emission monitor or an alternative method using either of the following procedures:

(i) Use the highest value from the alternative method associated with a simultaneous run by the 

applicable test method that does not exceed the applicable emission limit; or

(ii) Correlate the results of the two methods (the applicable test method results and the 

alternative monitoring method results) and establish an emission limit for the alternative 

monitoring system that corresponds to the applicable emission limit.

(5) The owner or operator shall submit the results required in paragraph (d)(4) of this section and 

all supporting documentation to the applicable regulatory authority for review and approval.

(6) The regulatory authority shall review and approve or disapprove the request for an alternative 

method and alternative emission limit. The criterion for approval shall be a demonstration (to the 

satisfaction of the regulatory authority) that the alternative method and alternative emission limit 

achieve a level of emission control that is the same as or better than the level that would have 

otherwise been achieved by the applicable method and emission limit.

(7) If the alternative method is approved by the applicable regulatory authority, the owner or 

operator shall perform monthly emission monitoring using the approved alternative monitoring 

procedure to demonstrate compliance with the alternative emission limit for each similar potline.

(e) Reduced sampling frequency. The owner or operator may submit a written request to the 

applicable regulatory authority to establish an alternative testing requirement to reduce the 

sampling of secondary TF emissions from potlines from monthly to quarterly.

(1) In the request, the owner or operator shall provide information and data demonstrating, to the 

satisfaction of the applicable regulatory authority, that secondary emissions of TF from potlines 

have low variability during normal operations using the procedures in paragraphs (e)(1)(i) or 

(e)(1)(ii) of this section.

(i) Submit data from 24 consecutive months of sampling that show the average TF emissions are 

less than 60 percent of the applicable limit and that no monthly performance test in the 24 

months of sampling exceeds 75 percent of the applicable limit; or

(ii) Submit data and a statistical analysis that the regulatory authority may evaluate based on the 

approach used in “Primary Aluminum: Statistical Analysis of Potline Fluoride Emissions and 

Alternative Sampling Frequency” (EPA–450–86–012, October 1986), which is available from 

the National Technical Information Service (NTIS), 5285 Port Royal Road, Springfield, VA 

22161.
28

(2) An approved alternative requirement must include a test schedule and the method to be used 

to measure emissions for performance tests.

(3) The owner or operator of a plant that has received approval of an alternative sampling 

frequency under §60.194 of this chapter is deemed to have approval of the alternative sampling 

frequency under this subpart.

(4) If emissions in excess of the applicable TF limit occur while performing quarterly sampling 

approved under paragraph (e)(1)(i) of this section, the owner or operator shall return to monthly 

sampling for at least 12 months and may reduce to quarterly sampling when:

(i) The average of all tests performed over the most recent 24-month period does not exceed 60 

percent of the applicable limit, and

(ii) No more than one monthly performance test in the most recent 24-month period exceeds 75 

percent of the applicable limit.

(5) If emissions in excess of the applicable TF limit occur while performing quarterly sampling 

approved under paragraph (e)(1)(ii) of this section, the owner or operator shall immediately 

return to the monthly sampling schedule required by paragraph (a) of this section until another 

request for an alternative sampling frequency is approved by the applicable regulatory authority.

(f) Monitoring parameters for emission control devices. The owner or operator shall install, 

operate, calibrate, and maintain a continuous parameter monitoring system for each emission 

control device. The owner or operator shall submit for approval by the regulatory authority a 

description of the parameter(s) to be monitored, the operating limits, and the monitoring 

frequency to ensure that the control device is being properly operated and maintained. An 

explanation of the criteria used for selection of the parameter(s), the operating limits, and the 

monitoring frequency, including how these relate to emission control also shall be submitted to 

the regulatory authority. Except as provided in paragraph (l) of this section, the following 

monitoring devices shall be installed:

(1) For dry alumina scrubbers, devices for the measurement of alumina flow and air flow;

(2) For dry coke scrubbers, devices for the measurement of coke flow and air flow;

(3) For wet scrubbers as the primary control system, devices for the measurement of water flow 

and air flow;

(4) For electrostatic precipitators, devices for the measurement of voltage and secondary current; 

and

(5) For wet roof scrubbers for secondary emission control:

(i) A device for the measurement of total water flow; and
29

(ii) The owner or operator shall inspect each control device at least once each operating day to 

ensure the control device is operating properly and record the results of each inspection.

(g) Visible emissions. The owner or operator shall visually inspect the exhaust stack(s) of each 

control device on a daily basis for evidence of any visible emissions indicating abnormal 

operation.

(h) Corrective action. If a monitoring device for a primary control device measures an operating 

parameter outside the limit(s) established pursuant to §63.847(h), if visible emissions indicating 

abnormal operation are observed from the exhaust stack of a control device during a daily

inspection, or if a problem is detected during the daily inspection of a wet roof scrubber for 

potline secondary emission control, the owner or operator shall initiate corrective action 

procedures within 1 hour. Failure to initiate the corrective action procedures within 1 hour or to 

take the necessary corrective actions to remedy the problem is a violation.

(i) Exceedances. If the limit for a given operating parameter associated with monitoring a 

specific control device is exceeded six times in any semiannual reporting period, then any 

subsequent exceedance in that reporting period is a violation. For the purpose of determining the 

number of exceedances, no more than one exceedance shall be attributed in any given 24-hour 

period.

(j) Weight of aluminum and green anodes. The owner or operator of a new or existing potline or 

anode bake furnace shall install, operate, and maintain a monitoring device to determine the daily 

weight of aluminum produced and the weight of green anode material placed in the anode bake 

furnace. The weight of green anode material may be determined by monitoring the weight of all 

anodes or by monitoring the number of anodes placed in the furnace and determining an average 

weight from measurements of a representative sample of anodes.

(k) Accuracy and calibration. The owner or operator shall submit recommended accuracy 

requirements to the regulatory authority for review and approval. All monitoring devices 

required by this section must be certified by the owner or operator to meet the accuracy 

requirements and must be calibrated in accordance with the manufacturer's instructions.

(l) Alternative operating parameters. The owner or operator may monitor alternative control 

device operating parameters subject to prior written approval by the applicable regulatory 

authority.

(m) Other control systems. An owner or operator using a control system not identified in this 

section shall request that the applicable regulatory authority include the recommended 

parameters for monitoring in the facility's part 70 permit.

(n) POM emissions from prebake potlines. Using the procedures in Sec. 63.847 and in the 

approved test plan, the owner or operator must monitor emissions of POM from each prebake

potline every five years. The owner or operator must compute and record the sum of the average 

primary and secondary emissions using the procedures of §§ 847(e)(2) or (e)(8).
30

[62 FR 52407, Oct. 7, 1997, as amended at 71 FR 20458, Apr. 20, 2006]

§63.849 Test methods and procedures.

(a) The owner or operator shall use the following reference methods to determine compliance 

with the applicable emission limits for TF and POM emissions:

(1) Method 1 in appendix A to part 60 of this chapter for sample and velocity traverses;

(2) Method 2 in appendix A to part 60 of this chapter for velocity and volumetric flow rate;

(3) Method 3 in appendix A to part 60 of this chapter for gas analysis;

(4) Method 13A or Method 13B in appendix A to part 60 of this chapter, or an approved 

alternative, for the concentration of TF where stack or duct emissions are sampled;

(5) Method 13A or Method 13B and Method 14 or Method 14A in appendix A to part 60 of this 

chapter or an approved alternative method for the concentration of TF where emissions are 

sampled from roof monitors not employing wet roof scrubbers;

(6) Method 315 in appendix A to this part or an approved alternative method for the 

concentration of POM where stack or duct emissions are sampled; and

(7) Method 315 in appendix A to this part and Method 14 in appendix A to part 60 of this chapter 

or an approved alternative method for the concentration of POM where emissions are sampled 

from roof monitors not employing wet roof scrubbers.

(b) The owner or operator of a VSS potline or a SWPB potline equipped with wet roof scrubbers 

for the control of secondary emissions shall use methods that meet the intent of the sampling 

requirements of Method 14 in appendix A to part 60 of this chapter and that are approved by the 

State. Sample analysis shall be performed using Method 13A or Method 13B in appendix A to 

part 60 of this chapter for TF, Method 315 in appendix A to this part for POM, or an approved 

alternative method.

(c) Except as provided in §63.845(g)(1), references to “potroom” or “potroom group” in Method 

14 in appendix A to part 60 of this chapter shall be interpreted as “potline” for the purposes of 

this subpart.

(d) For sampling using Method 14 in appendix A to part 60 of this chapter, the owner or operator 

shall install one Method 14 manifold per potline in a potroom that is representative of the entire 

potline, and this manifold shall meet the installation requirements specified in section 2.2.1 of 

Method 14 in appendix A to part 60 of this chapter.

(e) The owner or operator may use an alternative test method for TF or POM emissions 

providing:
31

(1) The owner or operator has already demonstrated the equivalency of the alternative method 

for a specific plant and has received previous approval from the Administrator or the applicable 

regulatory authority for TF or POM measurements using the alternative method; or

(2) The owner or operator demonstrates to the satisfaction of the applicable regulatory authority 

that the results from the alternative method meet the criteria specified in §§63.848(d)(1) and 

(d)(3) through (d)(6). The results from the alternative method shall be based on simultaneous 

sampling using the alternative method and the following reference methods:

(i) For TF, Methods 13 and 14 or Method 14A in appendix A to part 60 of this chapter; or

(ii) For POM, Method 315 in appendix A to this part and Method 14 in appendix A to part 60 of 

this chapter.

(f) The owner or operator must use ASTM Method D3177 – 02(2007) for determination of the 

sulfur content in anode coke shipments to determine compliance with the applicable facility wide 

emission limit for COS emissions.

§63.850 Notification, reporting, and recordkeeping requirements.

(a) Notifications. The owner or operator shall submit the following written notifications:

(1) Notification for an area source that subsequently increases its emissions such that the source 

is a major source subject to the standard;

(2) Notification that a source is subject to the standard, where the initial startup is before the 

effective date of the standard;

(3) Notification that a source is subject to the standard, where the source is new or has been 

reconstructed, the initial startup is after the effective date of the standard, and for which an 

application for approval of construction or reconstruction is not required;

(4) Notification of intention to construct a new major source or reconstruct a major source; of the 

date construction or reconstruction commenced; of the anticipated date of startup; of the actual 

date of startup, where the initial startup of a new or reconstructed source occurs after the 

effective date of the standard, and for which an application for approval of construction or 

reconstruction is required [see §§63.9(b)(4) and (b)(5)];

(5) Notification of initial performance test;

(6) Notification of initial compliance status;

(7) One-time notification for each affected source of the intent to use an HF continuous emission 

monitor;
32

(8) Notification of compliance approach. The owner or operator shall develop and submit to the 

applicable regulatory authority, if requested, an engineering plan that describes the techniques 

that will be used to address the capture efficiency of the reduction cells for gaseous hazardous air 

pollutants in compliance with the emission limits in §§63.843, 63.844, and 63.846; and

(9) One-time notification of startup of an existing potline or potroom group, anode bake furnace, 

or paste production plant that was shut down for a long period and subsequently restarted. The 

owner or operator must provide written notice to the Administrator at least 30 days before the 

startup.

(b) Performance test reports. The owner or operator shall report the results of the initial 

performance test as part of the notification of compliance status required in paragraph (a)(6) of 

this section. Except as provided in paragraph (d) of this section, the owner or operator shall 

submit a summary of all subsequent performance tests to the applicable regulatory authority on 

an annual basis.

(c) As of January 1, 2012 and within 60 days after the date of completing each performance test, 

as defined in §63.2, and as required in this subpart, the owner or operator must submit 

performance test data, except opacity data, electronically to the EPA’s Central Data Exchange by 

using the ERT (see http://www.epa.gov/ttn/chief/ert/erttool.html/) or other compatible electronic 

spreadsheet. Only data collected using test methods compatible with ERT are subject to this 

requirement to be submitted electronically into the EPA’s WebFIRE database.Startup, shutdown, 

and malfunction plan and reports. The owner or operator shall develop a written plan as 

described in §63.6(e)(3) that contains specific procedures to be followed for operating the source 

and maintaining the source during periods of startup, shutdown, and malfunction and a program 

of corrective action for malfunctioning process and control systems used to comply with the 

standards. The plan does not have to be submitted with the permit appplication or included in the 

operating permit. The permitting authority may review the plan upon request. In addition to the 

information required in §63.6(e)(3), the plan shall include:

(1) Procedures, including corrective actions, to be followed if a monitoring device measures an 

operating parameter outside the limit(s) established under §63.847(h), if visible emissions from 

an exhaust stack indicating abnormal operation of a control device are observed by the owner or 

operator during the daily inspection required in §63.848(g), or if a problem is detected during the 

daily inspection of a wet roof scrubber for potline secondary emission control required in 

§63.848(f)(5)(ii); and

(2) The owner or operator shall also keep records of each event as required by §63.10(b) and 

record and report if an action taken during a startup, shutdown, or malfunction is not consistent 

with the procedures in the plan as described in §63.6(e)(3)(iv).

(d) Reporting. In addition to the information required under §63.10 of the General Provisions, 

the owner or operator must provide semi-annual reports containing the information specified in 

paragraphs (d)(1) through (d)(2) of this section to the Administrator or designated authority.
33

(1) Excess emissions report. As required by §63.10(e)(3), the owner or operator must submit a 

report (or a summary report) if measured emissions are in excess of the applicable standard. The 

report must contain the information specified in §63.10(e)(3)(v) and be submitted semiannually 

unless quarterly reports are required as a result of excess emissions.

(2) If there was a malfunction during the reporting period, the owner or operator must submit a 

report that includes the number, duration, and a brief description for each type of malfunction 

which occurred during the reporting period and which caused or may have caused any applicable 

emission limitation to be exceeded. The report must also include a description of actions taken 

by an owner or operator during a malfunction of an affected source to minimize emissions in 

accordance with §§63.843(f) and 63.844(f), including actions taken to correct a 

malfunction.Excess emissions report. As required by §63.10(e)(3), the owner or operator shall 

submit a report (or a summary report) if measured emissions are in excess of the applicable 

standard. The report shall contain the information specified in §63.10(e)(3)(v) and be submitted 

semiannually unless quarterly reports are required as a result of excess emissions.

(e) Recordkeeping. The owner or operator shall maintain files of all information (including all 

reports and notifications) required by §63.10(b) and by this subpart.

(1) The owner or operator must retain each record for at least 5 years following the date of each 

occurrence, measurement, maintenance, corrective action, report, or record. The most recent 2 

years of records must be retained at the facility. The remaining 3 years of records may be 

retained offsite;

(2) The owner or operator may retain records on microfilm, on a computer, on computer disks, 

on magnetic tape, or on microfiche;

(3) The owner or operator may report required information on paper or on a labeled computer 

disc using commonly available and compatible computer software; and

(4) In addition to the general records required by §63.10(b), the owner or operator shall maintain 

records of the following information:

(i) Daily production rate of aluminum;

(ii) Daily production rate of green anode material placed in the anode bake furnace;

(iii) A copy of the startup, shutdown, and malfunction planReserved;

(iv) Records of design information for paste production plant capture systems;

(v) Records of design information for an alternative emission control device for a paste 

production plant;

(vi) Records supporting the monitoring of similar potlines demonstrating that the performance of 

similar potlines is the same as or better than that of potlines sampled by manual methods;
34

(vii) Records supporting a request for reduced sampling of potlines;

(viii) Records supporting the correlation of emissions measured by a continuous emission 

monitoring system to emissions measured by manual methods and the derivation of the 

alternative emission limit derived from the measurements;

(ix) The current implementation plan for emission averaging and any subsequent amendments;

(x) Records, such as a checklist or the equivalent, demonstrating that the daily inspection of a 

potline with wet roof scrubbers for secondary emission control has been performed as required in 

§63.848(f)(5)(ii), including the results of each inspection;

(xi) Records, such as a checklist or the equivalent, demonstrating that the daily visual inspection 

of the exhaust stack for each control device has been performed as required in §63.848(g), 

including the results of each inspection;

(xii) For a potline equipped with an HF continuous emission monitor, records of information and 

data required by §63.10(c);

(xiii) Records documenting the corrective actions taken when the limit(s) for an operating 

parameter established under §63.847(h) were exceeded, when visible emissions indicating 

abnormal operation were observed from a control device stack during a daily inspection required 

under §63.848(g), or when a problem was detected during the daily inspection of a wet roof 

scrubber for potline secondary control required in §63.848(f)(5)(ii);

(xiv) Records documenting any POM data that are invalidated due to the installation and startup

of a cathode; and

(xv) Records documenting the portion of TF that is measured as particulate matter and the 

portion that is measured as gaseous when the particulate and gaseous fractions are quantified 

separately using an approved test method.

(xvi) Records of the occurrence and duration of each malfunction of operation (i.e., process 

equipment) or the air pollution control equipment and monitoring equipment.

(xvii) Records of actions taken during periods of malfunction to minimize emissions in 

accordance with §§63.843 and 63.844, including corrective actions to restore malfunctioning 

process and air pollution control and monitoring equipment to its normal or usual manner of 

operation.

(f) All reports required by this subpart not subject to the requirements in paragraph (b) of this 

section must be sent to the Administrator at the appropriate address listed in §63.13. If 

acceptable to both the Administrator and the owner or operator of a source, these reports may be 

submitted on electronic media. The Administrator retains the right to require submittal of reports 

subject to paragraph (b) of this section in paper format.
35

[62 FR 52407, Oct. 7, 1997, as amended at 70 FR 66285, Nov. 2, 2005; 71 FR 20458, Apr. 20, 

2006]

§63.851 Regulatory authority review procedures.

(a) The applicable regulatory authority shall notify the owner or operator in writing of the need 

for additional time to review the submissions in paragraphs (a)(1) through (a)(5) of this section 

or of approval or intent to deny approval of the submissions in paragraphs (a)(1) through (a)(5) 

of this section within 60 calendar days after receipt of sufficient information to evaluate the 

submission. The 60-day period begins after the owner or operator has been notified that the 

submission is complete.

(1) The test plan in §63.847(b);

(2) Request to change limits for operating parameters in §63.847(h)(3);

(3) Request for similar potline monitoring in §63.848(d)(5);

(4) Request for reduced sampling frequency in §63.848(e); and

(5) Request for an alternative method in §63.849(e)(2).

(b) The applicable regulatory authority shall notify the owner or operator in writing whether the 

submission is complete within 30 calendar days of receipt of the original submission or within 30 

days of receipt of any supplementary information that is submitted. When a submission is 

incomplete, the applicable regulatory authority shall specify the information needed to complete 

the submission and shall give the owner or operator 30 calendar days after receipt of the 

notification to provide the information.

§63.852 Applicability of general provisions.

The requirements of the general provisions in subpart A of this part that are not applicable to the 

owner or operator subject to the requirements of this subpart are shown in appendix A of this 

subpart.

§63.853 Implementation and enforcement.

(a) This subpart can be implemented and enforced by the U.S. EPA, or a delegated authority 

such as the applicable State, local, or Tribal agency. If the U.S. EPA Administrator has delegated 

authority to a State, local, or Tribal agency, then that agency, in addition to the U.S. EPA, has the 

authority to implement and enforce this regulation. Contact the applicable U.S. EPA Regional 

Office to find out if this subpart is delegated to a State, local, or Tribal agency.

(b) In delegating implementation and enforcement authority of this subpart to a State, local, or 

Tribal agency under subpart E of this part, the authorities contained in paragraph (c) of this 
36

section are retained by the Administrator of U.S. EPA and cannot be transferred to the State, 

local, or Tribal agency.

(c) The authorities that cannot be delegated to State, local, or Tribal agencies are as specified in 

paragraphs (c)(1) through (4) of this section.

(1) Approval of alternatives to the requirements in §§63.840, 63.843 (with the exception of 

63.843(b)(3)), 63.844, 63.845(a) introductory text, (a)(1), (b) through (e), (h), 63.846(a) through 

(c), and 63.847(a)(1) and (4).

(2) Approval of major alternatives to test methods under §63.7(e)(2)(ii) and (f), as defined in 

§63.90, and as required in this subpart.

(3) Approval of major alternatives to monitoring under §63.8(f), as defined in §63.90, and as 

required in this subpart.

(4) Approval of major alternatives to recordkeeping and reporting under §63.10(f), as defined in 

§63.90, and as required in this subpart.

[68 FR 37354, June 23, 2003]

§63.854 Work Practice Standards for Periods of Startup.

(a) Startup of potlines. If you own or operate a new or existing primary aluminum reduction 

affected source, you must comply with the requirements of paragraphs (a)(1) through (7) of this 

section during startup for each affected potline.

(1) Develop a potline startup schedule before starting up the potline.

(2) Keep records of number of pots started per day.

(3) Bring the potline scrubbers and exhaust fans on line prior to energizing the first cell being 

restarted.

(4) Ensure that the primary capture and control system is operating at all times during startup.

(5) Keep pots covered during startup as much as practicable to include but not limited to 

minimizing the removal of covers or panels of the pots on which work is being performed.

(6) Inspect potlines daily during startup and perform the following work practices as specified in 

paragraphs (a)(6)(i) through (iv) of this section.

(i) Identify unstable pots as soon as practicable but in no case more than 12 hours from the time 

the pot became unstable;

Formatted: Font: Italic, No underline
37

(ii) Reduce cell temperatures to as low as practicable, but no higher than the maximum 

temperature specified in the operating plan described in paragraph (a)(7) of this section;

(iii) Reseal pot crusts that have been broken as often and as soon as practicable but in no case 

more than 24 hours from the time the crust was broken; and

(iv) Adjust pot parameters to their optimum levels, as specified in the operating plan described in 

paragraph (a)(7) of this section, including, but not limited to, the following parameters: alumina 

addition rate, exhaust air flow, cell voltage, feeding level, anode current and liquid and solid bath 

levels.

(7) Prepare an operating plan to minimize emissions during startup to include, but not limited to, 

the requirements in (a)(1) through (6) of this section.

(b) Startup of anode bake furnaces. If you own or operate a new or existing primary aluminum 

reduction affected source, you must comply with the requirements of paragraphs (b)(1) through 

(5) of this section during startup for each affected anode bake furnace.

(1) Develop an anode bake furnace startup schedule before starting up.

(2) Record time, date, duration and any nonroutine actions taken during startup of the furnaces.

(3) The emission control system should be operating within normal parametric limits prior to 

startup of the first anode bake furnace.

(4) If the emission control system is off line at any time during startup, the anode bake furnaces 

should be shut down immediately.

(5) Prepare an operating plan to minimize emissions during startup of the anode bake furnaces to 

include but not limited to the requirements in (b)(1) through (4) of this section.

§63.855 Affirmative defense for exceedance of emission limit during malfunction.

In response to an action to enforce the standards set forth in this subpart, you may assert an 

affirmative defense to a claim for civil penalties for exceedances of such standards that are 

caused by malfunction, as defined at §63.2. Appropriate penalties may be assessed, however, if 

you fail to meet your burden of proving all of the requirements in the affirmative defense. The 

affirmative defense shall not be available for claims for injunctive relief.

(a) To establish the affirmative defense in any action to enforce such a limit, you must timely 

meet the notification requirements in §63.850, and must prove by a preponderance of evidence 

that:

(1) The excess emissions:
38

(i) Were caused by a sudden, infrequent, and unavoidable failure of air pollution control and 

monitoring equipment, process equipment, or a process to operate in a normal or usual manner; 

and

(ii) Could not have been prevented through careful planning, proper design or better operation 

and maintenance practices; and

(iii) Did not stem from any activity or event that could have been foreseen and avoided, or 

planned for.

(iv) Were not part of a recurring pattern indicative of inadequate design, operation, or 

maintenance; and

(2) Repairs were made as expeditiously as possible when the applicable emissions limitations 

were being exceeded. Off-shift and overtime labor were used, to the extent practicable to make 

these repairs; and

(3) The frequency, amount and duration of the excess emissions (including any bypass) were 

minimized to the maximum extent practicable during periods of such emissions; and

(4) If the excess emissions resulted from a bypass of control equipment or a process, then the 

bypass was unavoidable to prevent loss of life, personal injury, or severe property damage; and

(5) All possible steps were taken to minimize the impact of the excess emissions on ambient air 

quality, the environment and human health; and

(6) All emissions monitoring and control systems were kept in operation if at all possible, 

consistent with safety and good air pollution control practices; and

(7) All of the actions in response to the excess emissions were documented by properly signed, 

contemporaneous operating logs; and

(8) At all times, the affected source was operated in a manner consistent with good practices for 

minimizing emissions; and

(9) A written root cause analysis has been prepared, the purpose of which is to determine, 

correct, and eliminate the primary causes of the malfunction and the excess emissions resulting 

from the malfunction event at issue. The analysis shall also specify, using best monitoring 

methods and engineering judgment, the amount of excess emissions that were the result of the 

malfunction.

(b) Notification. The owner or operator of the affected source experiencing an exceedance of its 

emissions limit(s) during a malfunction, shall notify the Administrator by telephone or facsimile 

transmission as soon as possible, but no later than two business days after the initial occurrence 

of the malfunction, it wishes to avail itself of an affirmative defense to civil penalties for that 

malfunction. The owner or operator seeking to assert an affirmative defense, shall also submit a 
39

written report to the Administrator within 45 days of the initial occurrence of the exceedance of 

the standards in this subpart to demonstrate, with all necessary supporting documentation, that it 

has met the requirements set forth in paragraph (e) of this section. The owner or operator may 

seek an extension of this deadline for up to 30 additional days by submitting a written request to 

the Administrator before the expiration of the 45 day period. Until a request for an extension has 

been approved by the Administrator, the owner or operator is subject to the requirement to 

submit such report within 45 days of the initial occurrence of the exceedance.

§§63.854856-63.859 [Reserved]

Table 1 to Subpart LL of Part 63—Potline TF Limits for Emission Averaging

Type

Monthly TF limit (1b/ton)

[for given number of potlines]

2 lines 3 lines 4 lines 5 lines 6 lines 7 lines 8 lines

CWPB1 1.7 1.6 1.5 1.5 1.4 1.4 1.4

CWPB2 2.9 2.8 2.7 2.7 2.6 2.6 2.6

CWPB3 2.3 2.2 2.2 2.1 2.1 2.1 2.1

VSS1 2 1.9 1.8 1.7 1.7 1.7 1.7

VSS2 2.6 2.5 2.5 2.4 2.4 2.4 2.4

HSS 2.5 2.4 2.4 2.3 2.3 2.3 2.3

SWPB 1.4 1.3 1.3 1.2 1.2 1.2 1.2

Table 2 to Subpart LL of Part 63—Potline POM Limits for Emission Averaging

Type

Quarterly POM limit (lb/ton)

[for given number of potlines]

2 lines 3 lines 4 lines 5 lines 6 lines 7 lines 8 lines

HSS 4.13.5 3.83.2 3.73.1 3.53.0 3.53.0 3.42.9 3.32.8

VSS1 2.1 2.0 1.9 1.9 1.8 1.8 1.8

VSS2 5.03.5 4.73.3 4.53.2 4.43.1 4.33.0 4.22.9 4.12.9

CWPB1 0.63 0.56 0.52 0.52 0.48 0.48 0.48

CWBP2 1.4 1.35 1.31 1.31 1.26 1.26 1.26

CWBP3 1.33 1.28 1.28 1.26 1.26 1.26 1.26

SWPB 0.63 0.56 0.52 0.52 0.48 0.48 0.48
40

[62 FR 52407, Oct. 7, 1997, as amended at 70 FR 66285, Nov. 2, 2005]

Table 3 to Subpart LL of Part 63—Anode Bake Furnace Limits for Emission Averaging

Number of furnaces

Emission limit (lb/ton of anode)

TF POM

2 0.11 0.17

3 0.090 0.17

4 0.077 0.17

5 0.070 0.17

Appendix A to Subpart LL of Part 63—Applicability of General Provisions

Appendix A to Subpart LL of Part 63—Applicability of General 

Provisions (40 CFR Part 63, Subpart A) 

Reference Applies to 

subpart LL

Comment

63.1 Yes

63.2 Yes

63.3 Yes

63.4 Yes

63.5 Yes

63.6(a), (b), (c) Yes

63.6(d) No Section reserved.

63.6(e)(1)(i) No See 63.843(f) and 

63.844(f) for general 

duty requirement.

63.6(e)(1)(ii) No

63.6(e)(1)(iii) Yes

63.6(e)(2) No Section reserved.

63.6(e)(3) No

63.6(f)(1) No

63.6(g) Yes

63.6(h) No No opacity limits in 

rule.

63.6(i) Yes

63.6(j) Yes

§63.7(a)-(d) Yes
41

Reference Applies to 

subpart LL

Comment

§63.7(e)(1) No See 63.847(d)

§63.7(e)(2)-(e)(4) Yes

63.7(f), (g), (h) Yes

63.8(a)-(b) Yes

63.8(c)(1)(i) No See 63.843(f) and 

63.844(f) for general 

duty requirement.

63.8(c)(1)(ii) Yes

63.8(c)(1)(iii) No

63.8(c)(2)-(d)(2) Yes

63.8(d)(3) Yes, except 

for last 

sentence

63.8(e)-(g) Yes

63.9(a),(b),(c),(e),(g),(h)(1)th

rough (3), (h)(5) and (6), (i) 

and (j)

Yes

63.9(f) No

63.9(h)(4) No Section Reserved

63.10 (a) Yes

63.10 (b)(1) Yes

63.10(b)(2)(i) No

63.10(b)(2)(ii) No See 63.850(e)(4)(xvi) 

and (xvii) for 

recordkeeping of 

occurrence and 

duration of 

malfunctions and 

recordkeeping of 

actions taken during 

malfunction.

63.10(b)(2)(iii) Yes

63.10(b)(2)(iv)-(b)(2)(v) No

63.10(b)(2)(vi)-(b)(2)(xiv) Yes

63.(10)(b)(3) Yes

63.10(c)(1)-(9) Yes

63.10(c)(10)-(11) No See 63.850(e)(4)(xvi) 

and (xvii)for 

recordkeeping of 

malfunctions. 

63.10(c)(12)-(c)(14) Yes

63.10(c)(15) No
42

Reference Applies to 

subpart LL

Comment

63.10(d)(1)-(4) Yes

63.10(d)(5) No See 63.850(d)(2) for 

reporting of 

malfunctions.

63.10(e)-((f) Yes

63.11 No Flares will not be 

used to comply with 

the emission limits

63.12 to 63.15 Yes

[40 CFR part 63, subpart A]

General provisions 

citation Requirement

Applies to 

subpart LL Comment

63.1(c)(2) No All are major sources.

63.2 Definition of 

“reconstruction”

No Subpart LL defines 

“reconstruction.”

63.6(c)(1) Compliance date 

for existing 

sources

No Subpart LL specifies compliance 

date for existing sources.

63.6(h) Opacity/VE 

standards

Only in §63.845 Opacity standards applicable only 

when incorporating the NSPS 

requirements under §63.845.

63.7(a)(2)(ii) and 

(iii)

Performance 

testing 

requirements

No Subpart LL specifies performance 

test dates.

63.8(c)(4)–(c)(8) CMS operation 

and maintenance

No Subpart LL does not require 

COMS/CMS or CMS performance 

specifications.

63.8(d) Quality control No Subpart LL does not require CMS 

or CMS performance evaluation.

63.8(e) Performance 

evaluation for 

CMS

No

63.9(b)(1)–(5) Initial notifications Yes, except as 

noted in 

§63.850(a)(9) includes requirement 

for startup of an existing affected 
43

“comment” 

column

source that has been shut down.

63.9(e) Notification of 

performance test

No Subpart LL specifies notification of 

performance tests.

63.9(f) Notification of VE 

or opacity test

Only in §63.845 Notification is required only when 

incorporating the NSPS 

requirements under §63.845.

63.9(g) Additional CMS 

notification

No

63.10(d)(2) Performance test 

reports

No Subpart LL specifies performance 

test reporting.

63.10(d)(3) Reporting 

VE/opacity 

observations

Only in §63.845 Reporting is required only when 

incorporating the NSPS 

requirements under §63.845.

63.10(e)(2) Reporting 

performance 

evaluations

No Subpart LL does not require 

performance evaluation for CMS.

63.11(a)–(b) Control device 

requirements

No Flares not applicable.

[62 FR 52407, Oct. 7, 1997, as amended at 70 FR 66285, Nov. 2, 2005]