This subpart establishes national emission standards for hazardous air pollutants (NESHAP) for affected sources at mercury cell chlor-alkali plants. This subpart also establishes requirements to demonstrate initial and continuous compliance with all applicable emission limitations and work practice standards in this subpart.

[87 FR 27018, May 6, 2022]

(a) You are subject to this subpart if you own or operate a mercury cell chlor-alkali plant.

(b) You are required to obtain a title V permit, whether your affected source is a part of a major source of hazardous air pollutant (HAP) emissions or a part of an area source of HAP emissions. A major source of HAP is a source that emits or has the potential to emit any single HAP at a rate of 10 tons or more per year or any combination of HAP at a rate of 25 tons or more per year. An area source of HAP is a source that has the potential to emit HAP but is not a major source. Nothing in this subpart revises how affected sources are aggregated for purposes of determining whether an affected source is a part of an area, nonmajor, or major source under any provisions of the Clean Air Act (CAA) or EPA's regulations. For information on aggregating affected sources to determine what is a source under title V, see the definition of major source in 40 CFR 70.2, 71.2 and 63.2.

(c) Beginning on December 19, 2006, the provisions of subpart E of 40 CFR part 61 that apply to mercury cell chlor-alkali plants, which are listed in paragraphs (c)(1) through (3) of this section, are no longer applicable.

(1) § 61.52(a);

(2) § 61.53(b) and (c); and

(3) § 61.55(b), (c) and (d).

[68 FR 70928, Dec. 19, 2003, as amended at 87 FR 27018, May 6, 2022]

(a) This subpart applies to each affected source at a plant site where chlorine and caustic are produced in mercury cells. This subpart applies to two types of affected sources: the mercury cell chlor-alkali production facility, as defined in paragraph (a)(1) of this section; and the mercury recovery facility, as defined in paragraph (a)(2) of this section.

(1) The mercury cell chlor-alkali production facility designates an affected source consisting of all cell rooms and ancillary operations used in the manufacture of product chlorine, product caustic, and by-product hydrogen at a plant site. This subpart covers mercury emissions from by-product hydrogen streams and end box ventilation system vents, mercury fugitive emissions associated with cell rooms, hydrogen systems, caustic systems, and storage areas for mercury-containing wastes; and chlorine fugitive emissions associated with the mercury cell chlor-alkali production facility.

(2) The mercury recovery facility designates an affected source consisting of all processes and associated operations needed for mercury recovery from wastes at a plant site. This subpart covers mercury emissions from mercury thermal recovery unit vents and fugitive emission sources of mercury associated with storage areas for mercury-containing wastes.

(b) An affected source at your mercury cell chlor-alkali plant is existing if you commenced construction of the affected source before July 3, 2002.

(c) A mercury recovery facility is a new affected source if you commence construction or reconstruction of the affected source after July 3, 2002. An affected source is reconstructed if it meets the definition of “reconstruction” in § 63.2.

[68 FR 70928, Dec. 19, 2003, as amended at 87 FR 27018, May 6, 2022]

(a) If you have an existing affected source, you must comply according to the dates specified in paragraphs (a)(1) through (5) of this section, as applicable.

(1) You must comply with each emission limitation, each work practice standard specified in paragraphs § 63.8192(a) through (f) or each work practice standard in paragraphs § 63.8192(e) through (g), and with each recordkeeping and reporting requirement in this subpart that applies to you by December 19, 2006, except as specified in paragraphs (a)(2) through (5) of this section.

(2) You must comply with each work practice standard in § 63.8192(a) through (c) and (e) through (h) and the electronic reporting requirements in § 63.8232(g), § 63.8252(g), and § 63.8254(e) by November 7, 2022.

(3) Until November 7, 2022, you must comply with the requirements in § 63.8226(a) and the requirements specified in the startup, shutdown, and malfunction plan required at § 63.8226(b).

(4) On and after November 7, 2022, you must comply with the applicable requirements in paragraph § 63.8226(c).

(5) On and after May 6, 2025, you must comply with the emission limitations in § 63.8190(a)(2)(ii) and the notification requirement in § 63.8252(h).

(b) If you have a new or reconstructed mercury recovery facility and its initial startup date is on or before December 19, 2003, you must comply with each emission limitation, work practice standard, and recordkeeping and reporting requirement in this subpart that applies to you by December 19, 2003.

(c) If you have a new or reconstructed mercury recovery facility and its initial startup date is after December 19, 2003, you must comply with each emission limitation, work practice standard, and recordkeeping and reporting requirement in this subpart that applies to you upon initial startup.

(d) You must meet the notification and schedule requirements in § 63.8252. Several of these notifications must be submitted before the compliance date for your affected source(s).

[68 FR 70928, Dec. 19, 2003, as amended at 87 FR 27019, May 6, 2022]

(a) Emission limits. You must meet each emission limit in paragraphs (a)(1) through (3) of this section that applies to you.

(1) New or reconstructed mercury cell chlor-alkali production facility. Emissions of mercury are prohibited from a new or reconstructed mercury cell chlor-alkali production facility.

(2) Existing mercury cell chlor-alkali production facility. Until the compliance date listed in § 63.8186(a)(5), you must comply with paragraph (a)(2)(i) of this section. On and after the compliance date listed in § 63.8186(a)(5), you must comply with paragraph (a)(2)(ii) of this section.

(i) During any consecutive 52-week period, you must not discharge to the atmosphere total mercury emissions in excess of the applicable limit in paragraph (a)(2)(i)(A) or (B) of this section calculated using the procedures in § 63.8243(a).

(A) 0.076 grams of mercury per megagram of chlorine produced (1.5 × 10−4 pounds of mercury per ton of chlorine produced) from all by-product hydrogen streams and all end box ventilation system vents when both types of emission points are present.

(B) 0.033 grams of mercury per megagram of chlorine produced (6.59 × 10−5 pounds of mercury per ton of chlorine produced) from all by-product hydrogen streams when end box ventilation systems are not present.

(ii) Emissions of mercury are prohibited from an existing mercury cell chlor-alkali production facility.

(3) New, reconstructed, or existing mercury recovery facility. You must not discharge to the atmosphere mercury emissions in excess of the applicable limit in paragraph (a)(3)(i) or (ii) of this section.

(i) 23 milligrams per dry standard cubic meter from each oven type mercury thermal recovery unit vent.

(ii) 4 milligrams per dry standard cubic meter from each non-oven type mercury thermal recovery unit vent.

(b) [Reserved]

[68 FR 70928, Dec. 19, 2003, as amended at 87 FR 27019, May 6, 2022]

In accordance with the compliance dates specified in § 63.8186(a)(1), you must meet the work practice requirements specified in paragraphs (a) through (f) of this section. As an alternative to the requirements specified in paragraphs (a) through (d) of this section, you may choose to comply with paragraph (g) of this section. On and after the compliance date specified in § 63.8186(a)(2) and until the compliance date specified in § 63.8186(a)(5), you must meet the work practice requirements specified in paragraphs (a) through (c) and (e) through (h) of this section.

(a) You must meet the work practice standards in Tables 1 through 4 to this subpart.

(b) You must adhere to the response intervals specified in Tables 1 through 4 to this subpart at all times. Nonadherence to the intervals in Tables 1 through 4 to this subpart constitutes a deviation and must be documented and reported in the compliance report, as required by § 63.8254(b), with the date and time of the deviation, cause of the deviation, a description of the conditions, and time actual compliance was achieved.

(c) As provided in § 63.6(g), you may request to use an alternative to the work practice standards in Tables 1 through 4 to this subpart.

(d) You must institute a floor-level mercury vapor measurement program to limit the amount of mercury vapor in the cell room environment through periodic measurement of mercury vapor levels and actions to be taken when a floor-level mercury concentration action level is exceeded. The program must meet the requirements listed in paragraphs (d)(1) through (4) of this section. As specified in § 63.8252(e)(1)(i) to implement this program, you must prepare and submit to the Administrator a floor-level mercury vapor measurement plan which must contain the elements listed in Table 5 to this subpart.

(1) You must utilize a mercury measurement device described in of Table 6 to this subpart to measure the level of mercury vapor in the cell room at floor-level.

(2) You must conduct at least one floor-level mercury vapor measurement evaluation each half day. This evaluation must include three measurements of the mercury concentration at locations representative of the entire cell room floor area. The average of these measurements must be recorded as specified in § 63.8156(c)(1). At a minimum, you must measure the level of mercury vapor above mercury-containing cell room equipment, as well as areas around the cells, decomposers, or other mercury-containing equipment.

(3) You must establish a floor-level mercury concentration action level that is no higher than 0.05 milligrams per cubic meter (mg/m 3).

(4) If a mercury concentration greater than the action level is measured during any floor-level mercury vapor measurement evaluation, you must meet the requirements in either paragraph (d)(4)(i) or (ii) of this section.

(i) If you determine that the cause of the elevated mercury concentration is an open electrolyzer, decomposer, or other maintenance activity, you must record the information specified in paragraphs (d)(4)(i)(A) through (C) of this section.

(A) A description of the maintenance activity resulting in elevated mercury concentration;

(B) The time the maintenance activity was initiated and completed; and

(C) A detailed explanation how all the applicable requirements of Table 1 to this subpart were met during the maintenance activity.

(ii) If you determine that the cause of the elevated mercury concentration is not an open electrolyzer, decomposer, or other maintenance activity, you must follow the procedures specified in paragraphs (d)(4)(ii)(A) and (B) of this section until the floor-level mercury concentration falls below the floor-level mercury concentration action level. You must also keep all the associated records for these procedures as specified in Table 9 to this subpart.

(A) Within 1 hour of the time the floor-level mercury concentration action level was exceeded, you must conduct each inspection specified in Table 2 to this subpart in the area where the concentration higher than the floor-level mercury concentration action level was measured, with the exception of the cell room floor and the pillars and beam inspections. (B) You must also inspect all decomposers, hydrogen system piping up to the hydrogen header, and other potential locations of mercury vapor leaks in the area using a technique specified in Table 6 to this subpart. You must correct any problem identified during these inspections according to the requirements in Tables 2 and 3 to this subpart.

(e) You must prepare, submit, and operate according to a written washdown plan designed to minimize fugitive mercury emissions through routine washing of surfaces where liquid mercury could accumulate. The written plan must address the elements contained in Table 7 to this subpart.

(f) You must keep records of the mass of all virgin mercury added to cells on an annual basis.

(g) You must institute a cell room monitoring program to continuously monitor the mercury vapor concentration in the upper portion of each cell room and to take corrective actions as quickly as possible when elevated mercury vapor levels are detected. As specified in § 63.8252(e)(1)(iv), you must prepare and submit to the Administrator, a cell room monitoring plan containing the elements listed in Table 5 to this subpart and meet the requirements in paragraphs (g)(1) through (4) of this section.

(1) You must utilize mercury monitoring systems that meet the requirements of Table 8 to this subpart.

(2) You must establish an action level according to the requirements in paragraphs (g)(2)(i) through (iii) of this section.

(i) Beginning on the compliance date specified for your affected source in § 63.8186, measure and record the mercury concentration for at least 30 days using a system that meets the requirements of paragraph (g)(1) of this section.

(ii) Using the monitoring data collected according to paragraph (g)(1)(i) of this section, establish your action level at the 75th percentile of the data set.

(iii) Submit your action level as part of your Notification of Compliance Status report according to § 63.8252(e)(1).

(3) Beginning on the compliance date specified for your affected source in § 63.8186, you must continuously monitor the mercury concentration in the cell room. Failure to monitor and record the data according to § 63.8256(c) (4)(ii) for 75 percent of the time in any 6-month period constitutes a deviation.

(4) If the average mercury concentration for any 1-hour period exceeds the action level established according to paragraph (g)(2) of this section, you must meet the requirements in either paragraph (g)(4)(i) or (ii) of this section.

(i) If you determine that the cause of the elevated mercury concentration is an open electrolyzer, decomposer, or other maintenance activity, you must record the information specified in paragraphs (g)(4)(i)(A) through (C) of this section.

(A) A description of the maintenance activity resulting in elevated mercury concentration;

(B) The time the maintenance activity was initiated and completed; and

(C) A detailed explanation how all the applicable requirements of Table 1 to this subpart were met during the maintenance activity.

(ii) If you determine that the cause of the elevated mercury concentration is not an open electrolyzer, decomposer, or other maintenance activity, you must follow the procedures specified in paragraphs (g)(4)(ii)(A) and (B) of this section until the mercury concentration falls below the action level. You must also keep all the associated records for these procedures as specified in Table 9 to this subpart.

(A) Within 1 hour of the time the action level was exceeded, you must conduct each inspection specified in Table 2 to this subpart, with the exception of the cell room floor and the pillars and beam inspections. You must correct any problem identified during these inspections in accordance with the requirements in Table 2 and 3 to this subpart.

(B) If the Table 2 inspections and subsequent corrective actions do not reduce the mercury concentration below the action level, you must inspect all decomposers, hydrogen system piping up to the hydrogen header, and other potential locations of mercury vapor leaks using a technique specified in Table 6 to this subpart. If a mercury vapor leak is identified, you must take the appropriate action specified in Table 3 to this subpart.

(h) You must comply with the requirements specified in paragraphs (h)(1) through (4) of this section to reduce fugitive chlorine emissions in the mercury cell chlor-alkali production facility affected source.

(1) You must identify each piece of equipment located throughout the mercury cell chlor-alkali production facility affected source that contains chlorine gas at a concentration of at least 5 percent by volume. You may identify equipment by a list or on a process or piping diagram. You may exclude equipment that is under negative pressure.

(2) You must install ambient chlorine sensors at the mercury cell chlor-alkali production facility affected source to measure the ambient chlorine concentration.

(i) Ambient chlorine sensors must have a detection limit of 0.5 ppmv or less.

(ii) The sensors must be operated continuously to obtain a measurement at least once each 15 minutes.

(iii) You must identify the location of the sensors by a list or on a process or piping diagram.

(iv) You must operate, calibrate, and maintain these sensors in accordance with manufacturer instructions.

(v) You must keep the necessary parts for routine repairs of the sensors readily available.

(3) You must perform inspections to identify leaks of chlorine using olfactory observations according to the schedules in paragraphs (h)(3)(i) and (ii) of this section. A leak is detected when there is an olfactory observation of a leak. If a leak is detected, you must comply with the repair provisions in paragraph (h)(4) of this section.

(i) At least once each 12 hours, you must inspect each piece of equipment located throughout the mercury cell chlor-alkali production facility affected source that contains chlorine gas at a concentration of greater than 5 percent by volume for chlorine leaks, excluding equipment that is under negative pressure.

(ii) Within 1 hour of detection of a 1-hour average chlorine concentration of 2 ppmv or greater by a sensor installed and operated in accordance with paragraph (h)(2) of this section, you must inspect each piece of equipment located throughout the mercury cell chlor-alkali production facility affected source that contains chlorine gas at a concentration of greater than 5 percent by volume for chlorine leaks, excluding equipment that is under negative pressure.

(4) You must undertake a first attempt at repair no later than 1 hour after the leak is detected, and the leak must be repaired no later than 72 hours after the leak is detected. A leak is repaired when there is no olfactory observation of a leak.

[68 FR 70928, Dec. 19, 2003, as amended at 87 FR 27019, May 6, 2022]

At all times you 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. The general duty to minimize emissions does not require you to make any further efforts to reduce emissions if levels required by the applicable standards have been achieved. Determination of whether a source is operating in compliance with operation and maintenance requirements 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, reports and inspection of the source.

[87 FR 27020, May 6, 2022] General Compliance Requirements

(a) Until November 7, 2022, you must be in compliance with the applicable emission limitations in § 63.8190 and the applicable work practice standards in § 63.8192 at all times, except during periods of startup, shutdown, and malfunction.

(b) Until November 7, 2022, you must develop and operate as specified by a written startup, shutdown, and malfunction plan (SSMP) according to the provisions in § 63.6(e)(3).

(c) On and after November 7, 2022, the provisions of paragraphs (a) and (b) of this section no longer apply, and you must be in compliance with the applicable emission limitations in § 63.8190 and the applicable work practice standards in § 63.8192 at all times.

[87 FR 27020, May 6, 2022]

(a) You must conduct a performance test no later than the compliance date that is specified in § 63.8186 for your affected source to demonstrate initial compliance with the applicable emission limit in § 63.8190(a)(2) for by-product hydrogen streams and end box ventilation system vents and the applicable emission limit in § 63.8190(a)(3) for mercury thermal recovery unit vents.

(b) For the applicable work practice standards in § 63.8192, you must demonstrate initial compliance within 30 calendar days after the compliance date that is specified for your affected source in § 63.8186.

You must conduct a performance test for each by-product hydrogen stream, end box ventilation system vent, and mercury thermal recovery unit vent according to the conditions detailed in paragraphs (a) through (d) of this section.

(a) You must conduct each performance test under conditions representative of normal operations. You may not conduct performance tests during periods of startup, shutdown, or malfunction. You must record the process information that is necessary to document operating conditions during the test and include in such record an explanation to support that such conditions represent normal operation. Upon request, you shall make available to the Administrator such records as may be necessary to determine the conditions of performance tests.

(b) For each performance test, you must develop a site-specific test plan in accordance with § 63.7(c)(2).

(c) You must conduct at least three test runs to comprise a performance test, as specified in § 63.7(e)(3) and in either paragraph (c)(1) or (2) of this section.

(1) The sampling time and sampling volume for each run must be at least 2 hours and 1.70 dry standard cubic meters (dscm). Mercury results below the analytical laboratory's detection limit must be reported using the reported analytical detection limit to calculate the sample concentration value and, in turn, the emission rate in the units of the standard; or

(2) The sampling time for each test run must be at least 2 hours and the mercury concentration in each field sample analyzed must be at least two times the reported analytical detection limit.

(d) You must use the test methods specified in paragraphs (d)(1) through (4) of this section and the applicable test methods in paragraphs (d)(5) through (7) of this section.

(1) Method 1 or 1A in appendix A of 40 CFR part 60 to determine the sampling port locations and the location and required number of sampling traverse points.

(2) Method 2, 2A, 2C, or 2D in appendix A of 40 CFR part 60 to determine the stack gas velocity and volumetric flow rate.

(3) Method 3, 3A, or 3B in appendix A of 40 CFR part 60 to determine the stack gas molecular weight.

(4) Method 4 in appendix A of 40 CFR part 60 to determine the stack gas moisture content.

(5) For each by-product hydrogen stream, Method 102 in appendix A of 40 CFR part 61 to measure the mercury emission rate after the last control device.

(6) For each end box ventilation system vent, Method 101 or 101A in appendix A of 40 CFR part 61 to measure the mercury emission rate after the last control device.

(7) For each mercury thermal recovery unit vent, Method 101 or 101A in appendix A of 40 CFR part 61 to measure the mercury emission rate after the last control device.

(e) During each test run for a by-product hydrogen stream and each test run for an end box ventilation system vent, you must continuously measure the electric current through the operating mercury cells and record a measurement at least once every 15 minutes.

(f) If the final control device is not a nonregenerable carbon adsorber and if you are demonstrating compliance using periodic monitoring under § 63.8240(b), you must continuously monitor the parameters listed in paragraph (f)(1) of this section and establish your maximum or minimum monitoring value (as appropriate for your control device) using the requirements in paragraph (f)(2) of this section.

(1) During the performance test specified in paragraphs (a) through (d) of this section, you must continuously monitor the control device parameters in paragraphs (f)(1)(i) through (vii) of this section and record a measurement at least once every 15 minutes.

(i) The exit gas temperature from uncontrolled streams;

(ii) The outlet temperature of the gas stream for the final (i.e., the farthest downstream) cooling system when no control devices other than coolers or demisters are used;

(iii) The outlet temperature of the gas stream from the final cooling system when the cooling system is followed by a molecular sieve or regenerative carbon adsorber;

(iv) Outlet concentration of available chlorine, pH, liquid flow rate, and inlet gas temperature of chlorinated brine scrubbers and hypochlorite scrubbers;

(v) The liquid flow rate and exit gas temperature for water scrubbers;

(vi) The inlet gas temperature of regenerative carbon adsorption systems; and

(vii) The temperature during the heating phase of the regeneration cycle for carbon adsorbers or molecular sieves.

(2) To establish a maximum monitoring value or minimum monitoring value, as appropriate for your final control device, you must average the recorded parameters in paragraphs (f)(1)(i) through (vi) of this section over the test period. If your final control device is a regenerative carbon adsorber, you must use the highest temperature reading measured in paragraph (f)(1)(vii) as the reference temperature in § 63.8244(b)(2)(v).

(g) Within 60 days after the date of completing each performance test specified in this section, you must submit the results of the performance test following the procedures specified in paragraphs (g)(1) through (3) of this section.

(1) Data collected using test methods supported by the EPA's Electronic Reporting Tool (ERT) as listed on the EPA's ERT website (https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert) at the time of the test. Submit the results of the performance test to the EPA via the Compliance and Emissions Data Reporting Interface (CEDRI), which can be accessed through the EPA's Central Data Exchange (CDX) (https://cdx.epa.gov/). The data must be submitted in a file format generated using the EPA's ERT. Alternatively, you may submit an electronic file consistent with the extensible markup language (XML) schema listed on the EPA's ERT website.

(2) Data collected using test methods that are not supported by the EPA's ERT as listed on the EPA's ERT website at the time of the test. The results of the performance test must be included as an attachment in the ERT or an alternate electronic file consistent with the XML schema listed on the EPA's ERT website. Submit the ERT generated package or alternative file to the EPA via CEDRI.

(3) Confidential business information (CBI). Do not use CEDRI to submit information you claim as CBI. Anything submitted using CEDRI cannot later be claimed CBI. Although we do not expect persons to assert a claim of CBI, if you wish to assert a CBI claim for some of the information submitted under paragraph (g)(1) or (2) of this section, you must submit a complete file, including information claimed to be CBI, to the EPA. The file must be generated using the EPA's ERT or an alternate electronic file consistent with the XML schema listed on the EPA's ERT website. Submit the file on a compact disc, flash drive, or other commonly used electronic storage medium and clearly mark the medium as CBI. Mail the electronic medium to U.S. EPA/OAQPS/CORE CBI Office, Attention: Group Leader, Measurement Policy Group, MD C404-02, 4930 Old Page Rd., Durham, NC 27703. The same file with the CBI omitted must be submitted to the EPA via the EPA's CDX as described in paragraphs (g)(1) and (2) of this section. All CBI claims must be asserted at the time of submission. Furthermore, under CAA section 114(c), emissions data is not entitled to confidential treatment, and the EPA is required to make emissions data available to the public. Thus, emissions data will not be protected as CBI and will be made publicly available.

[68 FR 70928, Dec. 19, 2003, as amended at 87 FR 27020, May 6, 2022]

(a) By-product hydrogen streams and end box ventilation system vents. You must determine the total grams of mercury per Megagram of chlorine production (g Hg/Mg Cl2) of chlorine produced from all by-product hydrogen streams and all end box ventilation system vents, if applicable, at a mercury cell chlor-alkali production facility, and you must follow the procedures in paragraphs (a)(1) through (6) of this section.

(1) Determine the mercury emission rate for each test run in grams per day for each by-product hydrogen stream and for each end box ventilation system vent, if applicable, from Method 101, 101A, or 102 (40 CFR part 61, appendix A).

(2) Calculate the average measured electric current through the operating mercury cells during each test run for each by-product hydrogen stream and for each end box ventilation system vent, if applicable, using Equation 1 of this section as follows:

$$ Where: CLavg, run = Average measured cell line current load during the test run, amperes; CLi, run = Individual cell line current load measurement (i.e., 15 minute reading) during the test run, amperes; and n = Number of cell line current load measurements taken over the duration of the test run.

(3) Calculate the amount of chlorine produced during each test run for each by-product hydrogen stream and for each end box ventilation system vent, if applicable, using Equation 2 of this section as follows:

$$ Where: PCl2,run = Amount of chlorine produced during the test run, megagrams chlorine (Mg Cl2); 1.3 × 10 −6 = Theoretical chlorine production rate factor, Mg Cl2 per hour per ampere per cell; CLavg,run = Average measured cell line current load during test run, amperes, calculated using Equation 1 of this section; ncell,run = Number of cells on-line during the test run; and trun = Duration of test run, hours.

(4) Calculate the mercury emission rate in grams of mercury per megagram of chlorine produced for each test run for each by-product hydrogen stream and for each end box ventilation system vent, if applicable, using Equation 3 of this section as follows:

$$ Where: EHg,run = Mercury emission rate for the test run, g Hg/Mg Cl2; Rrun = Measured mercury emission rate for the test run from paragraph (a)(1) of this section, grams Hg per day; trun = Duration of test run, hours; 24 = Conversion factor, hours per day; and PCl2,run = Amount of chlorine produced during the test run, calculated using Equation 2 of this section, Mg Cl2.

(5) Calculate the average mercury emission rate for each by-product hydrogen stream and for each end box ventilation system vent, if applicable, using Equation 4 of this section as follows:

$$ Where: EHg,avg = Average mercury emission rate for the by-product hydrogen stream or the end box ventilation system vent, if applicable, g Hg/Mg Cl2; EHg,run = Mercury emission rate for each test run for the by-product hydrogen stream or the end box ventilation system vent, if applicable, g Hg/Mg Cl2, calculated using Equation 3 of this section; and n = Number of test runs conducted for the by-product hydrogen stream or the end box ventilation system vent, if applicable.

(6) Calculate the total mercury emission rate from all by-product hydrogen streams and all end box ventilation system vents, if applicable, at the mercury cell chlor-alkali production facility using Equation 5 of this section as follows:

$$ Where: EHg,H2EB = Total mercury emission rate from all by-product hydrogen streams and all end box ventilation system vents, if applicable, at the affected source, g Hg/Mg Cl2; EHg,avg = Average mercury emission rate for each by-product hydrogen stream and each end box ventilation system vent, if applicable, g Hg/Mg Cl2, determined using Equation 4 of this section; and n = Total number of by-product hydrogen streams and end box ventilation system vents at the affected source.

(b) Mercury thermal recovery vents. You must determine the milligrams of mercury per dscm exhaust discharged from mercury thermal recovery unit vents, using the procedures in paragraphs (b)(1) and (2) of this section.

(1) Calculate the concentration of mercury in milligrams of mercury per dscm of exhaust for each test run for each mercury thermal recovery unit vent using Equation 6 of this section as follows:

$$ Where: CHg,run = Mercury concentration for the test run, milligrams of mercury per dry standard cubic meter of exhaust; mHg = Mass of mercury in test run sample, from Method 101, 101A, or 102, micrograms; 10-3 = Conversion factor, milligrams per microgram; and Vm(std) = Dry gas sample volume at standard conditions, from Method 101, 101A, or 102, dry standard cubic meters.

(2) Calculate the average concentration of mercury in each mercury thermal recovery unit vent exhaust using Equation 7 of this section as follows:

$$ Where: CHg,avg = Average mercury concentration for the mercury thermal recovery unit vent, milligrams of mercury per dry standard cubic meter exhaust; CHg,run = Mercury concentration for each test run, milligrams of mercury per dry standard cubic meter of exhaust, calculated using Equation 6 of this section; and n = Number of test runs conducted for the mercury thermal recovery unit vent.

(a) For each mercury cell chlor-alkali production facility, you have demonstrated initial compliance with the applicable emission limit for by-product hydrogen streams and end box ventilation system vents in § 63.8190(a)(2) if you comply with paragraphs (a)(1) and (2) of this section:

(1) Total mercury emission rate from all by-product hydrogen streams and all end box ventilation system vents, if applicable, at the affected source, determined according to §§ 63.8232 and 63.8234(a), did not exceed the applicable emission limit in § 63.8190(a)(2)(i) or (ii); and

(2) If you have chosen the periodic monitoring option specified in § 63.8240(b) and your final control device is not a nonregenerable carbon adsorber, you have established a parameter value according to § 63.8232(f)(2).

(b) For each mercury recovery facility, you have demonstrated initial compliance with the applicable emission limit for mercury thermal recovery unit vents in § 63.8190(a)(3) if you comply with paragraphs (b)(1) and (2) of this section.

(1) Mercury concentration in each mercury thermal recovery unit vent exhaust, determined according to §§ 63.8232 and 63.8234(b), did not exceed the applicable emission limit in § 63.8190(a)(3)(i) or (ii); and

(2) If you have chosen the periodic monitoring option in § 63.8240(b) and have a final control device that is not a nonregenerable carbon adsorber, you have established a maximum or minimum monitoring value, as appropriate for your control device according to § 63.8232(f)(2).

(c) Prior to the compliance date specified in § 63.8186(a)(2), for each affected source, you have demonstrated initial compliance with the applicable work practice standards in § 63.8192 if you comply with paragraphs (c)(1) through (7) of this section.

(1) You certify in your Notification of Compliance Status that you are operating according to the work practice standards in § 63.8192(a) through (d).

(2) You choose the continuous cell room monitoring program option, you certify in your Notification of Compliance Status that you are operating according to the continuous cell room monitoring program under § 63.8192(g) and you have established your action level according to § 63.8192(g)(2).

(3) You certify in your Notification of Compliance Status that you are operating according to your washdown plan.

(4) You have submitted your washdown plan as part of your Notification of Compliance Status.

(5) You have submitted your continuous cell room monitoring plan, if applicable, as part of your Notification of Compliance Status.

(6) You have submitted your floor-level cell room monitoring plan, if applicable, as part of your Notification of Compliance Status.

(7) You have submitted records of the mass of virgin mercury added to cells for the 5 years preceding the applicable compliance date for your affected source as a part of the Notification of Compliance Status.

(d) You must submit the Notification of Compliance Status containing the results of the initial compliance demonstration according to the requirements in § 63.8252(e).

(e) On and after the compliance date specified in § 63.8186(a)(2), for each affected source, you have demonstrated initial compliance with the applicable work practice standards for mercury emissions in § 63.8192(a) through (c) and (e) through (g) if you comply with paragraphs (e)(1) through (4) of this section.

(1) You have submitted a Revised Notification of Compliance Status containing the results of the initial compliance demonstration according to the requirements in § 63.8252(f).

(2) You certify in your Revised Notification of Compliance Status that you are operating according to the work practice standards for mercury emissions in § 63.8192(a) through (c), (e), and (f).

(3) You have submitted your cell room monitoring plan as part of your Revised Work Practice Notification of Compliance Status and you certify in your Revised Notification of Compliance Status that you are operating according to the continuous cell room monitoring program under § 63.8192(g).

(4) You have re-submitted your washdown plan as part of your Revised Notification of Compliance Status and you re-certify in your Revised Notification of Compliance Status that you are operating according to your washdown plan under § 63.8192(e).

(f) On and after the compliance date specified in § 63.8186(a)(2), for each affected source, you have demonstrated initial compliance with the applicable work practice standards for chlorine emissions in § 63.8192(h) if you meet the requirements of paragraphs (f)(1) through (3) of this section.

(1) You have installed chlorine sensors in accordance with § 63.8192(h)(2).

(2) You have certified in your Revised Notification of Compliance Status that you are operating according to the work practice standards in § 63.8192(h).

(3) You have submitted your Revised Notification of Compliance Status containing the results of the initial compliance demonstration according to the requirements in § 63.8252(f).

[68 FR 70928, Dec. 19, 2003, as amended at 87 FR 27020, May 6, 2022]

For each by-product hydrogen stream, each end box ventilation system vent, and each mercury thermal recovery unit vent, you must monitor the mercury emissions using the procedures in paragraph (a) or (b) of this section.

(a) You must continuously monitor the mercury concentration using a mercury continuous emissions monitor according to the requirements in §§ 63.8242(a) and 63.8244(a); or

(b) You must periodically monitor the mercury emissions according to the requirements in §§ 63.8242(b) and 63.8244(b).

(a) If you choose the continuous mercury monitoring option under § 63.8240(a), you must install, operate, and maintain each mercury continuous emissions monitor according to paragraphs (a)(1) through (5) of this section.

(1) Each mercury continuous emissions monitor must sample, analyze, and record the concentration of mercury at least once every 15 minutes.

(2) Each mercury continuous emissions monitor analyzer must have a detector with the capability to detect a mercury concentration of either 0.1 µg/m 3 or 0.5 times the mercury concentration level measured during the performance test conducted according to § 63.8232.

(3) In lieu of a promulgated performance specification as required in § 63.8(a)(2), you must develop a site-specific monitoring plan that addresses the elements in paragraphs (a)(3)(i) through (vi) of this section.

(i) Installation and measurement location downstream of the final control device for each by-product hydrogen stream, end box ventilation system vent, and mercury thermal recovery unit vent.

(ii) Performance and equipment specifications for the sample interface, the pollutant concentration analyzer, and the data collection and reduction system.

(iii) Performance evaluation procedures and acceptance criteria (i.e., calibrations).

(iv) Ongoing operation and maintenance procedures according to the requirements of § 63.8(c)(1), (3), and (4)(ii).

(v) Ongoing data quality assurance procedures according to the requirements of § 63.8(d)(1) and (2). You shall keep these written procedures on record for the life of the affected source or until the affected source is no longer subject to the provisions of this part, to be made available for inspection, upon request, by the Administrator. If the performance evaluation plan is revised, you shall keep previous (i.e., superseded) versions of the performance evaluation plan on record to be made available for inspection, upon request, by the Administrator, for a period of 5 years after each revision to the plan. The program of corrective action shall be included in the plan required under § 63.8(d)(2).

(vi) Ongoing recordkeeping and reporting procedures in accordance with the general requirements of § 63.10(c), (e)(1), and (e)(2)(i).

(4) You must conduct a performance evaluation of each mercury continuous emissions monitor according to your site-specific monitoring plan.

(5) You must operate and maintain each mercury continuous emissions monitor in continuous operation according to the site-specific monitoring plan.

(b) If you choose the periodic monitoring option and your final control device is not a nonregenerable carbon adsorber, you must install, operate, and maintain a continuous parameter monitoring system (CPMS) for each parameter specified in § 63.8232(f)(1), according to § 63.8(c).

[68 FR 70928, Dec. 19, 2003, as amended at 87 FR 27021, May 6, 2022]

(a) By-product hydrogen streams and end box ventilation system vents. For each consecutive 52-week period, you must determine the g Hg/Mg Cl2 produced from all by-product hydrogen streams and all end box ventilation system vents, if applicable, at a mercury cell chlor-alkali production facility using the procedures in paragraphs (a)(1) through (3) of this section. You must begin collecting data on the compliance date that is specified in § 63.8186 for your affected source and calculate your first 52-week average mercury emission rate at the end of the 52nd week after the compliance date.

(1) Each week, you must determine the weekly mercury emission rate in grams per week for each by-product hydrogen stream and for each end box ventilation system vent, if applicable, using one of the monitoring options in paragraph (a)(1)(i) or (ii) of this section.

(i) Continuous mercury monitoring according to §§ 63.8242 and 63.8244(a).

(ii) Periodic monitoring according to § 63.8244(b).

(2) Each week, you must determine the chlorine production and keep records of the production rate as required under § 63.8256(b)(6).

(3) Beginning 52 weeks after the compliance date specified in § 63.8186 for your affected source, you must calculate the 52-week average mercury emission rate from all by-product hydrogen steam and all end box ventilation system vents, if applicable, using Equation 1 of this section as follows:

$$ Where: EHg = 52-week average mercury emission rate for weeki, g Hg/Mg Cl2; Rweek, i = Mercury emission rate for weeki from paragraph (a)(1) of this section, g Hg per week; PCl2, weeki = Amount of chlorine produced during weeki, from paragraph (a)(2) of this section, Mg Cl2 per week.

(b) Mercury thermal recovery units. If you choose the continuous monitoring option in § 63.8240(a), you must demonstrate continuous compliance using paragraph (b)(1) of this section. If you choose the periodic monitoring option in § 63.8240(b), you must demonstrate continuous compliance using paragraph (b)(2) of this section.

(1) You must calculate the daily average mercury concentration using Equation 2 of this section as follows:

$$ Where: CHg, dailyavg = Average mercury concentration for the operating day, milligrams per dry standard cubic meter; CHg,i = Concentration of mercury measured at the interval i (i.e., 15 minute reading) using a mercury continuous emission monitor, milligrams per dry standard cubic meter; and n = Number of concentration measurements taken during the operating day.

(2) You must calculate the daily average mercury concentration using the procedures in § 63.8234(b).

(a) Continuous monitoring option. You must monitor mercury concentration according to § 63.8242(a) at all times that the affected source is operating with the exception of paragraphs (a)(1) and (2) of this section.

(1) Except for monitor malfunctions, associated repairs, and required quality assurance or control activities (including, as applicable, calibration checks and required zero and span adjustments), you must monitor mercury emissions continuously (or collect data at all required intervals) at all times that the affected source is operating. A monitoring malfunction is any sudden, infrequent, not reasonably preventable failure of the monitoring to provide valid data. Monitoring failures that are caused in part by poor maintenance or careless operation are not malfunctions.

(2) You may not use data recorded during monitoring malfunctions, associated repairs, and required quality assurance or control activities in data averages and calculations used to report emission or operating levels or to fulfill a minimum data availability requirement, if applicable. You must use all the data collected during all other periods in assessing compliance.

(b) Periodic monitoring option. If you choose the periodic monitoring option under § 63.8240(b), you must monitor according to the procedures in paragraph (b)(1) or (2) of this section.

(1) If your final control device is a nonregenerable carbon adsorber, then you must conduct at least three test runs per week meeting the criteria specified in § 63.8232(c)(1) and (2) to measure mercury emissions using the test methods specified in § 63.8232(d). Alternatively, you may use any other method that has been validated using the applicable procedures in Method 301, 40 CFR part 63, appendix A.

(2) If your final control device is anything other than a nonregenerable carbon adsorber, you must monitor according to the requirements of paragraphs (b)(2)(i) through (v) of this section.

(i) You must conduct at least three test runs per week meeting the criteria specified in § 63.8232(c)(1) and (2) to measure mercury emissions using the test methods specified in § 63.8232(d). Alternatively, you may use any other method that has been validated using the applicable procedures in Method 301, 40 CFR part 63, appendix A.

(ii) Except as specified in paragraph (b)(2)(iii) of this section, you must continuously collect data at least once every 15 minutes using a CPMS installed and operated according to § 63.8242(b) and record each 1-hour average from all measured data values during each 1-hour period for the applicable parameter identified in § 63.8232(f)(1) using the methods specified in § 63.8244(a).

(iii) As appropriate, you must continuously monitor the temperature specified in § 63.8232(f)(1)(vii) during each heating phase of the regeneration cycle of your carbon adsorber.

(iv) If the hourly average monitoring value of any applicable parameter recorded under paragraph (b)(2)(ii) of this section is below the minimum monitoring value or above the maximum monitoring value of that same parameter established under § 63.8232(f)(2) for 24 consecutive hours, your monitoring value is out of range and you must take corrective action as soon as practicable. The hourly average monitoring value must be above the minimum monitoring value or below the maximum monitoring value as appropriate for that parameter, within 48 hours of the period that the monitoring value is out of range.

(v) If your final control device is a regenerative carbon adsorber, when the maximum hourly value of the temperature measured according to paragraph (b)(2)(iii) of this section is below the reference temperature determined according to § 63.8232(f)(2) for three consecutive regeneration cycles, your monitoring value is out of range and you must take corrective action as soon as practicable. During the first regeneration cycle following the period that your monitoring value is out of range, the maximum hourly value must be above the reference temperature recorded according to § 63.8232(f)(2).

(a) By-product hydrogen streams and end box ventilation system vents. (1) For all by-product hydrogen streams and all end box ventilation system vents, if applicable, you must demonstrate continuous compliance with the applicable mercury emission limit by reducing the mercury emissions data to 52-week averages using Equation 1 of § 63.8243 and maintaining the 52-week average mercury emissions no higher than the applicable mercury emissions limit in § 63.8190(a)(2). To obtain the data to calculate these 52-week averages, you must monitor in accordance with paragraph (a)(1)(i) or (ii) of this section.

(i) Continuous monitoring option. You must collect mercury emissions data according to § 63.8244(a), representing at least 75 percent of the 15-minute periods in each operating day of the 52-week compliance period (with data recorded during monitoring malfunctions, associated repairs, and required quality assurance or control activities not counting toward the 75 percent requirement);

(ii) Periodic monitoring option. You must conduct at least three test runs per week to collect mercury emissions samples according to § 63.8244(b)(1) and (2)(i) and, if your final control device is not a nonregenerable carbon adsorber, you must collect data for monitoring values according to § 63.8244(b)(2)(ii) through (v).

(2) You must maintain records of mercury emissions and 52-week average values, as required in § 63.8256(b)(3) and (4). If your final control device is not a nonregenerable carbon adsorber, you must maintain records according to § 63.8256(d).

(b) Mercury thermal recovery unit vents. (1)(1) For each mercury thermal recovery unit vent, you must demonstrate continuous compliance with the applicable emission limit specified in § 63.8190(a)(3) by maintaining the outlet mercury daily-average concentration no higher than the applicable limit. To determine the outlet mercury concentration, you must monitor according to paragraph (b)(1)(i) or (ii) of this section.

(i) Continuous monitoring option. You must collect mercury concentration data according to § 63.8244(a), representing at least 75 percent of the 15-minute periods in the operating day (with data recorded during monitoring malfunctions, associated repairs, and required quality assurance or control activities not counting toward the 75 percent requirement).

(ii) Periodic monitoring option. You must conduct at least three test runs per week to collect mercury emissions samples according to § 63.8244(b)(1) and (2)(i) and, if your final control device is not a nonregenerable carbon adsorber, you must collect data for monitoring values according to § 63.8244(b)(2)(ii) through (v).

(2) You must maintain records of mercury emissions and daily average values as required in § 63.8256(b)(3). If your final control device is not a nonregenerable carbon adsorber, you must maintain records according to § 63.8256(d).

(c) You must demonstrate continuous compliance with the applicable work practice standards for mercury emissions in § 63.8192 by maintaining records in accordance with § 63.8256(c) and (e).

(d) You must demonstrate continuous compliance with the applicable work practice standards for chlorine emissions in § 63.8192(h) by continuously operating the chlorine sensors required by § 63.8192(h)(2), inspecting equipment in accordance with § 63.8192(h)(3), repairing equipment in accordance with § 63.8192(h)(4) and maintaining records in accordance with § 63.8256(f).

[68 FR 70928, Dec. 19, 2003, as amended at 87 FR 27021, May 6, 2022]

(a) Deviations. The instances specified in paragraphs (a)(1) through (4) of this section are deviations and must be reported according to the requirements in § 63.8254 and recorded according to the requirements in § 63.8256(a)(2).

(1) You must report each instance in which you did not meet each emission limitation in § 63.8190 that applies to you.

(2) You must report each instance in which you did not meet each work practice standard in § 63.8192 that applies to you.

(3) You must report each instance in which the corrective actions taken according to § 63.8244(b)(2)(iv) did not result in average monitoring values being within range within 48 hours of the period that the monitoring value is out of range.

(4) You must report each instance in which the corrective action taken according to § 63.8244(b)(2)(v) did not result in the maximum hourly temperature being above the reference temperature during the first regeneration cycle following the period that the monitoring value was out of range.

(b) Startups, shutdowns, and malfunctions. The provisions of paragraphs (b)(1) through (3) of this section apply until November 7, 2022. On and after November 7, 2022, the provisions of paragraphs (b)(1) through (3) of this section no longer apply. (1) Consistent with §§ 63.6(e) and 63.7(e)(1), deviations that occur during a period of startup, shutdown, or malfunction are not violations if you demonstrate to the Administrator's satisfaction that you were operating in accordance with § 63.6(e)(1).

(2) The Administrator will determine whether deviations that occur during a period of startup, shutdown, or malfunction are violations, according to the provisions in § 63.6(e).

(3) By-passing the control device for maintenance activities is not considered a startup, shutdown, or malfunction event.

[68 FR 70928, Dec. 19, 2003, as amended at 71 FR 20469, Apr. 20, 2006; 87 FR 27021, May 6, 2022]

(a) You must submit all of the notifications in §§ 63.7(b) and (c), 63.8(e) and (f) and 63.9(b) through (h) that apply to you by the dates specified.

(b) As specified in § 63.9(b)(2), if you start up your affected source before December 19, 2003, you must submit an Initial Notification no later than 120 calendar days after December 19, 2003, or no later than 120 days after the source becomes subject to this subpart, whichever is later.

(c) As specified in § 63.9(b)(3), if you start up your new or reconstructed mercury recovery facility on or after December 19, 2003, you must submit your initial notification not later than 120 days after you become subject to this subpart.

(d) For each performance test that you are required to conduct for by-product hydrogen streams and end box ventilation system vents and for mercury thermal recovery unit vents, you must submit a notification of intent to conduct a performance test at least 60 calendar days before the performance test is scheduled to begin as required in § 63.7(b)(1).

(e) You must submit a Notification of Compliance Status according to paragraphs (e)(1) and (2) of this section.

(1) For each initial compliance demonstration that does not include a performance test, you must submit the Notification of Compliance Status before the close of business on the 30th calendar day following the completion of the initial compliance demonstration. The Notification of Compliance Status must contain the items in paragraphs (e)(1)(i) through (iv) of this section:

(i) If you choose not to implement a cell room monitoring program according to § 63.8192(g), a certification that you are operating according to the applicable work practice standards for mercury emissions in § 63.8192(a) through (d) and your floor-level mercury vapor measurement plan required by § 63.8192(d).

(ii) The washdown plan, and you must certify that you are operating according to the washdown plan specified in § 63.8192(f).

(iii) The mass of virgin mercury added to cells for the 5 years preceding the compliance date.

(iv) If you choose to implement a cell room monitoring program according to § 63.8192(g), your cell room monitoring plan.

(2) For each initial compliance demonstration that does include a performance test, you must submit the Notification of Compliance Status, including the performance test results, before the close of business on the 60th calendar day following the completion of the performance test according to § 63.10(d)(2). The Notification of Compliance Status must contain the information in § 63.9(h)(2)(ii)(A) through (G). The site-specific monitoring plan required in § 63.8242(a)(3) must also be submitted.

(f) You must submit a Revised Notification of Compliance Status before the close of business on the date 30 days after the compliance date in § 63.8186(a)(2) containing the items in paragraphs (f)(1) through (5) of this section:

(1) A certification that you are operating according to the work practice standards for mercury emissions in § 63.8192(a) through (c) and (e) through (g).

(2) Your cell room monitoring plan, including your initial action level determined in accordance with § 63.8192(g)(2), and a certification that you are operating according to the continuous cell room monitoring program under § 63.8192(g).

(3) Your washdown plan, and a certification that you are operating according to your washdown plan under § 63.8192(e).

(4) Records of the mass of virgin mercury added to cells for every year since 2001.

(5) A certification that you have installed chlorine sensors in accordance with § 63.8192(h)(2) and that you are operating according to the work practice standards for chlorine emissions in § 63.8192(h).

(g) You must submit all subsequent Notification of Compliance Status reports and Revised Notification of Compliance Status reports in PDF format to the EPA via CEDRI, which can be accessed through EPA's CDX (https://cdx.epa.gov/).

(h) You must submit a notification of compliance with the prohibition of mercury emissions as specified in paragraphs (e)(1) and (2) of this section.

(1) The notification must include the information specified in paragraph (e)(1)(i) and (ii) of this section.

(i) A certification that the requirement of § 63.8190(a)(2)(ii) has been met.

(ii) A brief explanation of how the requirement of § 63.8190(a)(2)(ii) has been met.

(2) You must submit this notification before the close of business on the 30th calendar day following the date when compliance with § 63.8190(a)(2)(ii) is attained.

[68 FR 70928, Dec. 19, 2003, as amended at 85 FR 73914, Nov. 19, 2020, 85 FR 84262, Dec. 28, 2020; 87 FR 27021, May 6, 2022]

(a) Compliance report due dates. You must submit a semiannual compliance report to your permitting authority according to the requirements in paragraphs (a)(1) through (4) of this section.

(1) The first compliance report must cover the period beginning on the compliance date that is specified for your affected source in § 63.8186 and ending on June 30 or December 31, whichever date comes first after the compliance date that is specified for your affected source in § 63.8186.

(2) The first compliance report must be postmarked or delivered no later than July 31 or January 31, whichever date comes first after your first compliance reporting period.

(3) Each subsequent compliance report must cover the semiannual reporting period from January 1 through June 30 or the semiannual reporting period from July 1 through December 31.

(4) Each subsequent compliance report must be postmarked or delivered no later than July 31 or January 31, whichever date comes first after the end of the semiannual reporting period.

(b) Compliance report contents. Each compliance report must contain the information in paragraphs (b)(1) through (3) of this section, and as applicable, paragraphs (b)(5) through (13) of this section.

(1) Company name and address.

(2) Statement by a responsible official, with that official's name, title, and signature, certifying the truth, accuracy, and completeness of the report.

(3) Date of report and beginning and ending dates of the reporting period.

(4) [Reserved]

(5) If there were no deviations from the continuous compliance requirements in § 63.8246 that apply to you, a statement that there were no deviations from the emission limitations, work practice standards, and operation and maintenance standards during the reporting period.

(6) If there were no periods during which the mercury continuous emission monitor or CPMS (if applicable) were out-of-control as specified in § 63.8(c)(7), a statement that there were no periods during the which the mercury continuous emissions monitor or CPMS (if applicable) were out-of-control during the reporting period.

(7) For each deviation from the requirements for work practice standards in § 63.8192, the information in paragraphs (b)(7)(i) and (ii) of this section.

(i) For each deviation from the mercury work practice standards in Tables 1 through 4 to this subpart that occurs at an affected source (including deviations where the response intervals were not adhered to as described in § 63.8192(b)), each deviation from the cell room monitoring program monitoring and data recording requirements in § 63.8192(g)(3), and each deviation from the response intervals required by § 63.8192(g)(4) when an action level is exceeded, the compliance report must contain the information in paragraphs (b)(1) through (3) of this section and the information in paragraphs (b)(7)(i)(A) through (C) of this section.

(A) The total operating time of each affected source during the reporting period.

(B) Information on the number, date, time, duration, and cause of deviations (including unknown cause, if applicable), as applicable, and the corrective action taken.

(C) A list of the affected sources or equipment.

(ii) For each deviation from the fugitive chlorine requirements in § 63.8192(h), including periods when the chlorine sensors required by § 63.8192(h)(2) were not operating; instances where the chlorine sensors required by § 63.8192(h)(2) were not calibrated and maintained in accordance with manufacturer instructions or spare parts were not maintained; instances where inspections were not performed in accordance with § 63.8192(h)(3)(i) and (ii); and instances where leak repair intervals in § 63.8192(h)(4) were not met; the compliance report must contain the information in paragraphs (b)(1) through (3) of this section and the information in paragraphs (b)(7)(ii)(A) through (C) of this section.

(A) The total operating time of each affected source during the reporting period.

(B) Information on the number, date, time, duration, and cause of deviations (including unknown cause, if applicable), as applicable, and the corrective action taken.

(C) A list of the affected sources or equipment.

(8) For each deviation from an emission limitation occurring at an affected source where you are using a mercury continuous emission monitor, according to the site-specific monitoring plan required in § 63.8242(a)(3), to comply with the emission limitation in this subpart, you must include the information in paragraphs (b)(1) through (3) of this section and the information in paragraphs (b)(8)(i) through (xv) of this section.

(i) A list of the affected sources and equipment.

(ii) The date and time that each deviation started and stopped.

(iii) For each deviation, the cause of the deviation (including unknown cause, if applicable), as applicable, and corrective action taken.

(iv) For each deviation, an estimate of the quantity of each regulated pollutant emitted over any emission limit.

(v) A description of the method used to estimate the emissions.

(vi) The date and time of each instance in which a continuous monitoring system was inoperative, except for zero (low-level) and high-level checks.

(vii) The date, time, and duration of each instance in which a continuous monitoring system was out-of-control, including the information in § 63.8(c)(8).

(viii) A summary of the total duration of the deviation during the reporting period and the total duration as a percent of the total source operating time during that reporting period.

(ix) A breakdown of the total duration of the deviations during the reporting period including those that are due to control equipment problems, process problems, other known causes, and other unknown causes.

(x) A summary of the total duration of continuous monitoring system downtime during the reporting period and the total duration of monitoring system downtime as a percent of the total source operating time during the reporting period.

(xi) An identification of each hazardous air pollutant that was monitored at the affected source.

(xii) A brief description of the process units.

(xiii) A brief description of the continuous monitoring system.

(xiv) The date of the latest continuous monitoring system certification or audit.

(xv) A description of any changes in monitoring system, processes, or controls since the last reporting period.

(9) For each deviation from an operation and maintenance standard occurring at an affected source where you are using the periodic monitoring option specified in § 63.8240(b) and your final control device is not a nonregenerable carbon adsorber, the compliance report must include the information in paragraphs (b)(1) through (3) of this section and the information in paragraphs (b)(9)(i) through (xiii) of this section.

(i) A list of the affected sources or equipment.

(ii) The total operating time of each affected source during the reporting period.

(iii) Information on the number, duration, and cause of deviations (including unknown cause, if applicable), as applicable, and the corrective action taken.

(iv) For each deviation, an estimate of the quantity of each regulated pollutant emitted over any emission limit.

(v) A description of the method used to estimate the emissions.

(vi) The date and time of each instance in which a CPMS was inoperative, except for zero (low-level) and high-level checks.

(vii) The date, time, and duration of each instance in which a CPMS was out-of-control, including the information specified in § 63.8(c)(8).

(viii) A summary of the total duration of the deviation during the reporting period and the total duration as a percent of the total source operating time during that reporting period.

(ix) A breakdown of the total duration of the deviations during the reporting period including those that are due to control equipment problems, process problems, other known causes, and other unknown causes.

(x) A summary of the total duration of continuous monitoring system downtime during the reporting period and the total duration of monitoring system downtime as a percent of the total source operating time during the reporting period.

(xi) A brief description of the CPMS.

(xii) The date of the latest CPMS certification or audit.

(xiii) A description of any changes in monitoring system, processes, or controls since the last reporting period.

(10) The compliance report must contain the mass of virgin mercury added to cells for the reporting period.

(11) The compliance report must contain each instance in which corrective actions taken under § 63.8244(b)(2)(iv) did not result in average monitoring values being within range within 48 hours of the period that the monitoring value is out of range.

(12) The compliance report must contain each instance in which corrective action taken according to § 63.8244(b)(2)(v) did not result in the maximum hourly temperature being above the reference temperature during the first regeneration cycle following the period that the monitoring value was out of range.

(13) The compliance report must contain the information specified in paragraphs (b)(13)(i) through (iii) for each instance where the 1-hour average concentration of chlorine detected by a chlorine sensor required by § 63.8192(h)(2) was 2 ppmv or greater.

(i) The date and times a chlorine sensor detected chlorine concentrations of 2 ppmv or greater.

(ii) The location of the sensor.

(iii) The date and time that the sensor returned to a 1-hour average concentration of less than 2 ppmv.

(14) The compliance report must contain the information specified in paragraphs (b)(14)(i) and (ii) for all inspections conducted under either § 63.8192(h)(3)(i) or (ii). You must also record the information in paragraphs (b)(14)(iii) through (vii) of this section for each leak identified.

(i) The date of each inspection.

(ii) The reason for each inspection (i.e., a routine inspection conducted each 12 hours or an inspection conducted in response to a 2 ppmv or greater 1-hour average concentration of chlorine, as detected by a sensor).

(iii) Location of the leak.

(iv) Date and time the leak was identified.

(v) Date and time of initial repair attempt.

(vi) Date and time the leak is repaired.

(vii) A description of the repair made to stop the leak.

(c) [Reserved]

(d) Title V monitoring report. After your affected source has been issued a title V operating permit pursuant to 40 CFR part 70 or 40 CFR part 71, you must report all deviations from permit requirements and provide reports of any required monitoring in your semiannual monitoring report as required by 40 CFR 70.6(a)(3)(iii)(A) or 40 CFR 71.6(a)(3)(iii)(A). If you submit a semiannual compliance report for an affected source as required by this subpart as part of the semiannual monitoring report required by 40 CFR 70.6(a)(3)(iii)(A) or 40 CFR 71.6(a)(3)(iii)(A), and the semiannual compliance report includes all information required by the 40 CFR part 70 or 40 CFR part 71 semiannual monitoring report for the deviations that are reported in the semiannual compliance report, submission of the semiannual compliance report satisfies your obligation to report the same deviation information in the semiannual monitoring report. However, in such situations, the semiannual monitoring report must cross-reference the semiannual compliance report, and submission of a semiannual compliance report does not otherwise affect any obligation you may have to report deviations from permit requirements for an affected source to your permitting authority under 40 CFR part 70 or 40 CFR part 71.

(e) The owner or operator must submit semiannual compliance reports in PDF formatto the EPA viaCEDRI, which can be accessedthrough EPA's CDX (https://cdx.epa.gov/).

[68 FR 70928, Dec. 19, 2003, as amended at 87 FR 27022, May 6, 2022]

(a) General records. You must keep the records in paragraphs (a)(1) and (2) of this section.

(1) A copy of each notification and report that you submitted to comply with this subpart, including all documentation supporting any initial notification or Notification of Compliance Status that you submitted, according to the requirements in § 63.10(b)(2)(xiv).

(2) The records specified in paragraphs (a)(2)(i) and (ii) of this section related to deviations.

(i) Record actions taken to minimize emissions in accordance with § 63.8222 and any corrective actions taken to return the affected unit to its normal or usual manner of operation.

(ii) Records of the information reported as required in § 63.8254(b)(7) through (9) and (11) through (13).

(b) Records associated with the by-product hydrogen stream and end box ventilation system vent emission limitations and the mercury thermal recovery unit vent emission limitations. You must keep the records in paragraphs (b)(1) through (5) of this section related to the emission limitations in § 63.8190(a)(2) through (3) and (b).

(1) Records of performance tests as required in § 63.10(b)(2)(viii).

(2) Records of the mercury emissions monitoring conducted during the performance tests.

(3) Records of the continuous or periodic mercury emissions monitoring data.

(4) Records of the 52-week rolling average mercury emissions.

(5) Records associated with your site-specific monitoring plan required in § 63.8242(a)(3) (i.e., results of inspections, calibrations, and validation checks of each mercury concentration continuous monitoring system (CMS)).

(6) Records of chlorine production on a weekly basis.

(c) Records associated with the work practice standards for mercury emissions that must be kept prior to the compliance date in § 63.8186(a)(2).

(1) If you choose not to institute a cell room monitoring program according to § 63.8192(g) of this subpart, you must keep the records specified in paragraphs (c)(1)(i) through (v) of this section.

(i) Records specified in Table 9 to this subpart related to the work practice standards in Tables 1 through 4 of this subpart.

(ii) Your current floor-level mercury vapor measurement plan.

(iii) Records of the average value calculated from at least three measurements taken according to your floor-level mercury vapor measurement plan.

(iv) Records indicated in § 63.8192(d)(4)(i) for maintenance activities that cause the floor-level mercury concentration to exceed the action level.

(v) Records of all inspections and corrective actions taken in response to a non-maintenance related situation in which the mercury vapor concentration exceeds the floor-level mercury concentration action level.

(2) You must maintain a copy of your current washdown plan and records of when each washdown occurs.

(3) You must maintain records of the mass of virgin mercury added to cells for each reporting period.

(4) If you choose to institute a cell room monitoring program according to § 63.8192(g) of this subpart, you must keep your current cell room monitoring plan and the records specified in paragraphs (c)(4)(i) through (v) of this section.

(i) Records of the monitoring conducted in accordance with § 63.8192(g)(2)(i) to establish your action level, and records demonstrating the development of this action level.

(ii) Records of the cell room mercury concentration monitoring data collected.

(iii) Instances when the action level is exceeded.

(iv) Records specified in § 63.8192(g)(4)(i) for maintenance activities that cause the mercury vapor concentration to exceed the action level.

(v) Records of all inspections and corrective actions taken in response to a non-maintenance related situation in which the mercury vapor concentration exceeds the action level.

(d) Records associated with the periodic monitoring option if your final control device is not a nonregenerable carbon adsorber. You must keep the records in paragraph (d)(1) through (3) of this section.

(1) Records of the CPMS data collected during the performance test as specified in § 63.8232(f)(1).

(2) Records documenting the development of the maximum monitoring value or minimum monitoring value, as appropriate, according to § 63.8232(f)(2).

(3) Records of hourly average values of applicable parameters monitored as specified in § 63.8244(b)(2)(ii) or (iii).

(e) Records associated with the work practice standards for mercury emissions that must be kept after the compliance date in § 63.8186(a)(2).

(1) The records specified in Table 9 to this subpart related to the work practice standards in Tables 1 through 4 of this subpart.

(2) You must maintain a copy of your current washdown plan and records of when each washdown occurs.

(3) You must maintain records of the mass of virgin mercury added to cells for each reporting period.

(4) You must keep your current cell room monitoring plan and the records specified in paragraphs (e)(4)(i) through (v) of this section.

(i) Records of the monitoring conducted in accordance with § 63.8192(g)(2)(i) to establish your action level, and records demonstrating the development of this action level.

(ii) Records of the cell room mercury concentration monitoring data collected.

(iii) Instances when the action level is exceeded.

(iv) Records specified in § 63.8192(g)(4)(i) for maintenance activities that cause the mercury vapor concentration to exceed the action level.

(v) Records of all inspections and corrective actions taken in response to a non-maintenance related situation in which the mercury vapor concentration exceeds the action level.

(f) You must keep the records specified in paragraphs (f)(1) through (4) of this section associated with the work practice standards for fugitive chlorine emissions specified in § 63.8192(h) after the compliance date in § 63.8186(a)(2).

(1) Identification of all equipment in the mercury cell chlor-alkali production facility affected source containing chlorine gas at a concentration of greater than 5 percent by volume. You may exclude equipment that is under negative pressure.

(2) Records of the information reported as required in § 63.8254(b)(13) and (14).

(3) You must record the information specified in paragraphs (f)(3)(i) through (iv) of this section for the chlorine sensors required by § 63.8192(h)(2).

(i) The location, manufacturer, and model number of each sensor.

(ii) The manufacturer's instructions for operation, maintenance, and calibration of the chlorine sensors.

(iii) Records of all maintenance and calibration of the chlorine sensors.

(iv) You must record all periods when the chlorine sensors are not operating.

(4) You must maintain records of all chlorine concentration measurements.

[68 FR 70928, Dec. 19, 2003, as amended at 87 FR 27023, May 6, 2022]

(a) Your records must be in a form suitable and readily available for expeditious inspection and review, according to § 63.10(b)(1).

(b) As specified in § 63.10(b)(1), you must keep each record for 5 years following the date of each occurrence, measurement, maintenance, corrective action, report, or record.

(c) You must keep each record on site for at least 2 years after the date of each occurrence, measurement, maintenance, corrective action, report, or record, according to § 63.10(b)(1). You can keep the records offsite for the remaining 3 years.

Table 10 to this subpart shows which parts of the General Provisions in §§ 63.1 through 63.13 apply to you.

[87 FR 27023, May 6, 2022]

(a) This subpart can be implemented and enforced by us, the United States Environmental Protection Agency (U.S. EPA), or a delegated authority such as your State, local, or tribal agency. If the EPA Administrator has delegated authority to your State, local, or tribal agency, then that agency has the authority to implement and enforce this subpart. You should contact your EPA Regional Office to find out if this subpart is delegated to your 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 section are retained by the EPA Administrator and are not transferred to the State, local, or tribal agency.

(c) The authorities in paragraphs (c)(1) through (5) of this section will not be delegated to State, local, or tribal agencies.

(1) Approval of alternatives under § 63.6(g) to the non-opacity emission limitations in § 63.8190 and work practice standards in § 63.8192.

(2) Approval of major alternatives to test methods under § 63.7(e)(2)(ii) and (f) and as defined in § 63.90.

(3) Approval of major alternatives to monitoring under § 63.8(f) and as defined in § 63.90.

(4) Approval of major alternatives to recordkeeping and reporting under § 63.10(f) and as defined in § 63.90.

(5) Approval of an alternative to any electronic reporting to the EPA required by this subpart.

[68 FR 70928, Dec. 19, 2003, as amended at 87 FR 27023, May 6, 2022]

Terms used in this subpart are defined in the CAA, in § 63.2, and in this section as follows:

Aqueous liquid means a liquid mixture in which water is the predominant component.

Brine means an aqueous solution of alkali metal chloride, as sodium chloride salt solution or potassium chloride salt solution, that is used in the electrolyzer as a raw material.

By-product hydrogen stream means the hydrogen gas from each decomposer that passes through the hydrogen system and is burned as fuel, transferred to another process as raw material, or discharged directly to the atmosphere.

Caustic means an aqueous solution of alkali metal hydroxide, as sodium hydroxide or potassium hydroxide, that is produced in the decomposer.

Caustic basket means a fixture adjacent to the decomposer that contains a serrated funnel over which the caustic from the decomposer passes, breaking into droplets such that electric current is interrupted.

Caustic system means all vessels, piping, and equipment that convey caustic and remove mercury from the caustic stream. The caustic system begins at the decomposer and ends after the primary filters.

Cell room means a building or other structure in which one or more mercury cells are located.

Continuous parameter monitoring system, or CPMS, 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 of control system parameters.

Control device means a piece of equipment (such as condensers, coolers, chillers, heat exchangers, mist eliminators, absorption units, and adsorption units) that removes mercury from gaseous streams.

Decomposer means the component of a mercury cell in which mercury amalgam and water react in bed of graphite packing (within a cylindrical vessel), producing caustic and hydrogen gas and returning mercury to its elemental form for re-use in the process.

Deviation means any instance in which an affected source subject to this subpart, or an owner or operator of such a source:

(1) Fails to meet any requirement or obligation established by this subpart including, but not limited to, any emission limitation (including any operating limit) or work practice standard (including any monitoring plan);

(2) Fails to meet any term or condition that is adopted to implement an applicable requirement in this subpart and that is included in the title V operating permit for any affected source required to obtain such a permit; or

(3) Fails to take corrective actions within 48 hours that result in parameter monitoring values being within range.

Electrolyzer means the main component of the mercury cell that consists of an elongated, shallow steel trough that holds a layer of mercury as a flowing cathode. The electrolyzer is enclosed by side panels and a top that suspends metal anodes. In the electrolyzer, brine is fed between a flowing mercury cathode and metal anodes in the presence of electricity to produce chlorine gas and an alkali metal-mercury amalgam (mercury amalgam).

Emission limitation means any emission limit or operating limit.

End box means a component of a mercury cell for transferring materials between the electrolyzer and the decomposer. The inlet end box collects and combines raw materials at the inlet end of the cell, and the outlet end box separates and directs various materials either into the decomposer or out of the cell.

End box ventilation system means all vessels, piping, and equipment that evacuate the head space of each mercury cell end box (and possibly other vessels and equipment) to the atmosphere. The end box ventilation system begins at the end box (and other vessel or equipment which is being evacuated) and terminates at the end box ventilation system vent. The end box ventilation system includes all control devices.

End box ventilation system vent means the discharge point of the end box ventilation system to the atmosphere after all control devices.

Hydrogen leak means hydrogen gas (containing mercury vapor) that is escaping from the decomposer or hydrogen system.

Hydrogen system means all vessels, piping, and equipment that convey a by-product hydrogen stream. The hydrogen system begins at the decomposer and ends at the point just downstream of the last control device. The hydrogen system includes all control devices.

In liquid mercury service means containing or coming in contact with liquid mercury.

Liquid mercury accumulation means one or more liquid mercury droplets, or a pool of liquid mercury, present on the floor or other surface exposed to the atmosphere.

Liquid mercury leak means the liquid mercury that is dripping or otherwise escaping from process equipment.

Liquid mercury spill means a liquid mercury accumulation resulting from a liquid mercury that leaked from process equipment or that dripped during maintenance or handling.

Mercury cell means a device consisting of an electrolyzer and decomposer, with one or more end boxes, a mercury pump, and other components linking the electrolyzer and decomposer.

Mercury cell amalgam seal pot means a compartment through which mercury amalgam passes from an outlet end box to a decomposer.

Mercury cell chlor-alkali plant means all contiguous or adjoining property that is under common control, where mercury cells are used to manufacture product chlorine, product caustic, and by-product hydrogen and where mercury may be recovered from wastes.

Mercury cell chlor-alkali production facility means an affected source consisting of all cell rooms and ancillary operations used in the manufacture of product chlorine, product caustic, and by-product hydrogen at a mercury cell chlor-alkali plant.

Mercury concentration CMS, or mercury concentration continuous monitoring system, means a CMS, as defined in § 63.2, that continuously measures the concentration of mercury.

Mercury-containing wastes means waste materials containing mercury, which are typically classified under Resource Conservation and Recovery Act (RCRA) solid waste designations. K071 wastes are sludges from the brine system. K106 are wastewater treatment sludges. D009 wastes are non-specific mercury-containing wastes, further classified as either debris or nondebris (i.e., cell room sludges and carbon from decomposes).

Mercury pump means a component of a mercury cell for conveying elemental mercury re-created in the decomposer to the beginning of the mercury cell. A mercury pump is typically found either as an in-line mercury pump (near a mercury suction pot or mercury seal pot) or submerged mercury pump (within a mercury pump tank or mercury pump seal).

Mercury recovery facility means an affected source consisting of all processes and associated operations needed for mercury recovery from wastes at a mercury cell chlor-alkali plant.

Mercury thermal recovery unit means the retort(s) where mercury-containing wastes are heated to volatilize mercury and the mercury recovery/control system (control devices and other equipment) where the retort off-gas is cooled, causing mercury to condense and liquid mercury to be recovered.

Mercury thermal recovery unit vent means the discharge point of the mercury thermal recovery unit to the atmosphere after all recovery/control devices. This term encompasses both oven type vents and non-oven type vents.

Mercury vacuum cleaner means a cleanup device used to draw a liquid mercury spill or accumulation (via suction pressure) into a closed compartment.

Non-oven type mercury thermal recovery unit vent means the discharge point to the atmosphere after all recovery/control devices of a mercury thermal recovery unit in which the retort is either a rotary kiln or single hearth retort.

Open-top container means any container that does not have a tight-fitting cover that keeps its contents from being exposed to the atmosphere.

Oven type mercury thermal recovery unit vent means the discharge point to the atmosphere after all recovery/control devices of a mercury thermal recovery unit in which each retort is a batch oven retort.

Responsible official means responsible official as defined in 40 CFR 70.2.

Retort means a furnace where mercury-containing wastes are heated to drive mercury into the gas phase. The types of retorts used as part of mercury thermal recovery units at mercury cell chlor-alkali plants include batch oven retorts, rotary kilns, and single hearth retorts.

Spalling means fragmentation by chipping.

Sump means a large reservoir or pit for wastewaters (primarily washdown waters).

Trench means a narrow channel or depression built into the length of a cell room floor that leads washdown materials to a drain.

Vent hose means a connection for transporting gases from the mercury cell.

Virgin mercury means mercury that has not been processed in an onsite mercury thermal recovery unit or otherwise recovered from mercury-containing wastes onsite.

Washdown means the act of rinsing a floor or surface with a stream of aqueous liquid to cleanse it of a liquid mercury spill or accumulation, generally by driving it into a trench.

Week means any consecutive seven-day period.

Work practice standard means any design, equipment, work practice, or operational standard, or combination thereof, that is promulgated pursuant to section 112(h) of the CAA.

[68 FR 70928, Dec. 19, 2003, as amended at 87 FR 27023, May 6, 2022]

As stated in § 63.8192, you must meet the work practice standards in the following table:

As stated in § 63.8192, you must meet the work practice standards in the following table:

As stated in § 63.8192, you must meet the work practice standards in the following table:

As stated in § 63.8192, you must meet the work practice standards in the following table:

Your Floor-Level Mercury Vapor Measurement Plan required by § 63.8192(d) prior to the applicable compliance date specified in § 63.8186(a)(2) and Cell Room Monitoring Plan required by § 63.8192(g) must contain the elements listed in the following table:

[68 FR 70928, Dec. 19, 2003, as amended at 87 FR 27024, May 6, 2022]

As stated in Tables 1 and 2 of Subpart IIIII, examples of techniques for equipment problem identification, leak detection and mercury vapor measurements can be found in the following table:

As stated in § 63.8192, your written washdown plan must address the elements contained in the following table:

As stated in § 63.8192(g)(1), your mercury monitoring system must meet the requirements contained in the following table:

As stated in § 63.8256(c), you must keep the records (related to the work practice standards) specified in the following table:

As stated in § 63.8262, you must comply with the applicable General Provisions requirements according to the following table:

[87 FR 27024, May 6, 2022]