(a) [Reserved]

(b)(1) NOX emission limits. (i) United States Steel Corporation, Keetac: An emission limit of 1.5 lbs NOX/MMBtu, based on a 30-day rolling average, shall apply to the Grate Kiln pelletizing furnace (EU030), beginning 3 years from March 8, 2013. However, for any 30, or more, consecutive days when only natural gas is used a limit of 1.2 lbs NOX/MMBtu, based on a 30-day rolling average, shall apply.

(ii) Hibbing Taconite Company—(A) An aggregate emission limit of 1.5 lbs NOX/MMBtu, based on a 30-day rolling average, shall apply to the combined NOX emissions from the three indurating furnaces, Line 1 (EU020), Line 2 (EU021), and Line 3 (EU022), beginning on February 2, 2026. To determine the aggregate emission rate, the combined NOX emissions from Lines 1, 2, and 3 shall be divided by the total heat input to the three lines (in MMBtu) during every rolling 30-day period.

(B) Compliance with this emission limit shall be demonstrated with data collected by a continuous emissions monitoring system (CEMS) for NOX.

(iii) United States Steel Corporation, Minntac: An aggregate emission limit of 1.6 lbs NOX/MMBtu, based on a 30-day rolling average, shall apply to the combined NOX emissions from the five indurating furnaces: Line 3 (EU225), Line 4 (EU261), Line 5 (EU282), Line 6 (EU315), and Line 7 (EU334). To determine the aggregate emission rate, the combined NOX emissions from lines 3, 4, 5, 6 and 7 shall be divided by the total heat input to the five lines (in MMBTU) during every rolling 30-day period commencing either upon notification of a starting date by United States Steel Corporation, Minntac, or with the 30-day period from September 1, 2019 to September 30, 2019, whichever occurs first. The aggregate emission rate shall subsequently be determined on each day, 30 days after the starting date contained in such notification or September 30, 2019, whichever occurs first.

(iv) United Taconite—(A) An aggregate emission limit of 3.0 lbs NOX/MMBtu, based on a 30-day rolling average, shall apply to the combined NOX emissions from the two indurating furnaces, Grate Kiln Line 1 (EU040) and Grate Kiln Line 2 (EU042), beginning on February 2, 2026. To determine the aggregate emission rate, the combined NOX emissions from Grate Kiln Line 1 and Grate Kiln Line 2 shall be divided by the total heat input to the two lines (in MMBtu) during every rolling 30-day period.

(B) Compliance with this emission limit shall be demonstrated with data collected by a continuous emissions monitoring system (CEMS) for NOX.

(v) Minorca Mine—(A) An emission limit of 1.6 lbs NOX/MMBtu, based on a 30-day rolling average, shall apply to the Minorca Mine indurating furnace (EU026). This emission limit will become enforceable on February 2, 2026.

(B) Compliance with this emission limit will be demonstrated with data collected by a continuous emissions monitoring system (CEMS) for NOX.

(vi) Northshore Mining Company—Silver Bay: An emission limit of 1.5 lbs NOX/MMBtu, based on a 30-day rolling average, shall apply to Furnace 11 (EU100/EU104) beginning October 10, 2018. An emission limit of 1.5 lbs NOX/MMBtu, based on a 30-day rolling average, shall apply to Furnace 12 (EU110/114) beginning October 11, 2019. However, for any 30, or more, consecutive days when only natural gas is used at either Northshore Mining Furnace 11 or Furnace 12, a limit of 1.2 lbs NOX/MMBtu, based on a 30-day rolling average, shall apply. An emission limit of 0.085 lbs NOX/MMBtu, based on a 30-day rolling average, shall apply to Process Boiler #1 (EU003) and Process Boiler #2 (EU004) beginning October 10, 2021. The 0.085 lbs NOX/MMBtu emission limit for each process boiler applies at all times a unit is operating, including periods of start-up, shut-down and malfunction.

(2) SO2 emission limits. (i) United States Steel Corporation, Keetac: An emission limit of 225 lbs SO2/hr, based on a 30-day rolling average, shall apply to the Grate Kiln pelletizing furnace (EU030). Any coal burned at Keetac shall have a sulfur content of 0.60 percent sulfur by weight or less based on a monthly block average. The sampling and calculation methodology for determining the sulfur content of fuel must be described in the monitoring plan required at paragraph (e)(8)(x) of this section. Compliance with these requirements for EU030 is required beginning 3 months from March 8, 2013.

(ii) Hibbing Taconite Company—(A) An aggregate emission limit of 247.8 lbs SO2/hour, based on a 30-day rolling average, shall apply to the combined SO2 emissions from the three indurating furnaces, Line 1 (EU020), Line 2 (EU0021), and Line 3 (EU022), beginning on February 10, 2017. To determine the aggregate emission rate, the combined SO2 emissions from Lines 1, 2, and 3 shall be divided by the total hours of operation of the three lines during every rolling 30-day period.

(B) Compliance with this emission limit shall be demonstrated with data collected by a continuous emissions monitoring system (CEMS) for SO2.

(C) Emissions resulting from the combustion of fuel oil are not included in the calculation of the 30-day rolling average. However, if any fuel oil is burned after the first day that SO2 CEMS are required to be operational, then the information specified in (b)(2)(vii) must be submitted, for each calendar year, to the Regional Administrator at [email protected] no later than 30 days after the end of each calendar year so that a limit can be set.

(iii) United States Steel Corporation, Minntac: An aggregate emission limit for indurating furnace Lines 3-7 (EU225, EU261, EU282, EU315, and EU334) of 498 lbs SO2/hr shall apply when all lines are producing flux pellets. An aggregate emission limit of 630 lbs SO2/hr shall apply to Lines 3-7 when Line 3-5 are producing acid pellets and Lines 6 and 7 are producing flux pellets. An aggregate emission limit of 800 lbs SO2/hr shall apply to Lines 3-7 when all lines are producing acid pellets. The SO2 emission limits are based on a 30-day rolling average and apply beginning 3 months from March 8, 2013. The emission limit for a given 30-day rolling average period is calculated using a weighted average as follows:

Where: L30 = the limit for a given 30 day averaging period nf = the number of days in the 30 day period that the facility is producing flux pellets on lines 3-7 naf = the number of days in the 30 day period that the facility is producing acid pellets on lines 3-5 and flux pellets on lines 6 and 7 na = the number of days in the 30 day period that the facility is producing acid pellets on lines 3-7

Also, beginning 3 months from March 8, 2013, any coal burned at Minntac's Lines 3-7 shall have a sulfur content of 0.60 percent sulfur by weight or less based on a monthly block average. The sampling and calculation methodology for determining the sulfur content of fuel must be described in the monitoring plan required at paragraph (e)(8)(x) of this section.

(iv) United Taconite: An aggregate emission limit of 529.0 lbs SO2/hr, based on a 30-day rolling average, shall apply to the Line 1 pellet furnace (EU040) and Line 2 pellet furnace (EU042) beginning six months after May 12, 2016. Compliance with this aggregate emission limit shall be demonstrated with data collected by a continuous emissions monitoring system (CEMS) for SO2. The owner or operator must start collecting CEMS data for SO2 beginning six months after May 12, 2016 and submit the data to EPA no later than 30 days from the end of each calendar quarter. Beginning six months after May 12, 2016, any coal burned on UTAC Grate Kiln Line 1 or Line 2 shall have no more than 1.5 percent sulfur by weight based on a monthly block average. The sampling and calculation methodology for determining the sulfur content of coal must be described in the monitoring plan required for this furnace.

(v) Minorca Mine—(A) An emission limit of 68.2 lbs SO2/hr, based on a 30-day rolling average, shall apply to the indurating furnace (EU026) beginning February 2, 2026.

(B) Compliance with this emission limit shall be demonstrated with data collected by a continuous emissions monitoring system (CEMS) for SO2.

(C) Emissions resulting from the combustion of fuel oil are not included in the calculation of the 30-day rolling average. However, if any fuel oil is burned after the first day that SO2 CEMS are required to be operational, then the information specified in (b)(2)(vii) must be submitted, for each calendar year, to the Regional Administrator at [email protected] no later than 30 days after the end of each calendar year so that a limit can be set.

(vi) Northshore Mining Company—Silver Bay—(A) An aggregate emission limit of 17.0 lbs SO2/hr, based on a 30-day rolling average, shall apply to Furnace 11 (EU100/EU104) and Furnace 12 (EU110/EU114) beginning February 2, 2026. To determine the aggregate emission rate, the combined SO2 emissions from Furnace 11 and Furnace 12 shall be divided by the total hours of operation of the two furnaces during every rolling 30-day period.

(B) Compliance with these emission limits shall be demonstrated with data collected by a continuous emissions monitoring system (CEMS) for SO2.

(C) Emissions resulting from the combustion of fuel oil are not included in the calculation of the 30-day rolling average. However, if any fuel oil is burned after the first day that SO2 CEMS are required to be operational, then the information specified in (b)(2)(vii) must be submitted, for each calendar year, to the Regional Administrator at [email protected] no later than 30 days after the end of each calendar year so that a limit can be set.

(D) The owner or operator may submit to EPA for approval an alternative monitoring procedure request. The request shall include at least one year of CEMS data demonstrating consistent values at or below 5 lbs SO2/hr. The alternative monitoring procedure request shall not remove the obligation to maintain and operate a flow rate monitor in the stack. If approved, the owner or operator would not be required to operate the SO2 CEMS and may demonstrate continuous compliance using an emission factor derived from the average of at least one year of existing SO2 data using the procedure set forth in the site specific monitoring plan, and verified by annual stack tests using EPA approved test methods, multiplied by the daily measured flow rate as recorded by the flow rate monitor and recorded as the daily lb/hr SO2 emission rate.

(vii) Starting with the first day that SO2 CEMS are required to be operational, for the facilities listed in paragraphs (b)(2)(i)-(b)(2)(vi) of this section, records shall be kept for any day during which fuel oil is burned (either alone or blended with other fuels) in one or more of a facility's indurating furnaces. These records must include, at a minimum, the gallons of fuel oil burned per hour, the sulfur content of the fuel oil, and the SO2 emissions in pounds per hour. If any fuel oil is burned after the first day that SO2 CEMS are required to be operational, then the records must be submitted, for each calendar year, to the Regional Administrator no later than 30 days after the end of each calendar year.

(c) Testing and monitoring. (1) The owner or operator of the respective facility shall install, certify, calibrate, maintain and operate continuous emissions monitoring systems (CEMS) for NOX on United States Steel Corporation, Keetac unit EU030; Hibbing Taconite Company units EU020, EU021, and EU022; United States Steel Corporation, Minntac units EU225, EU261, EU282, EU315, and EU334; United Taconite units EU040 and EU042; Minorca Mine unit EU026; and Northshore Mining Company-Silver Bay units Furnace 11 (EU100/EU104) and Furnace 12 (EU110/EU114). Compliance with the emission limits for NOX shall be determined using data from the CEMS.

(2) The owner or operator shall install, certify, calibrate, maintain, and operate CEMS for SO2 on United States Steel Corporation, Keetac unit EU030; Hibbing Taconite Company units EU020, EU021, and EU022; United States Steel Corporation, Minntac units EU225, EU261, EU282, EU315, and EU334; United Taconite units EU040 and EU042; Minorca Mine unit EU026; and Northshore Mining Company-Silver Bay units Furnace 11 (EU100/EU104) and Furnace 12 (EU110/EU114).

(3) The owner or operator shall install, certify, calibrate, maintain, and operate one or more continuous diluent monitor(s) (O2 or CO2) and continuous stack gas flow rate monitor(s) on the BART affected units to allow conversion of the NOX and SO2 concentrations to units of the standard (lbs/MMBTU and lbs/hr, respectively) unless a demonstration is made that a diluent monitor and/or continuous flow rate monitor are not needed for the owner or operator to demonstrate compliance with applicable emission limits in units of the standards.

(4) For purposes of this section, all CEMS required by this section must meet the requirements of paragraphs (c)(4)(i) through (xiv) of this section.

(i) All CEMS must be installed, certified, calibrated, maintained, and operated in accordance with 40 CFR part 60, appendix B, Performance Specification 2 (PS-2) and appendix F, Procedure 1.

(ii) CEMS must be installed and operational such that the operational status of the CEMS identified in paragraphs (c)(1) and (2) of this section shall be verified by, as a minimum, completion of the manufacturer's written requirements or recommendations for installation, operation, and calibration of the devices.

(iii) The owner or operator must conduct a performance evaluation of each CEMS in accordance with 40 CFR part 60, appendix B, PS-2. The performance evaluations must be completed no later than 60 days after the respective CEMS installation.

(iv) The owner or operator of each CEMS must conduct periodic Quality Assurance, Quality Control (QA/QC) checks of each CEMS in accordance with 40 CFR part 60, appendix F, Procedure 1. The first CEMS accuracy test will be a relative accuracy test audit (RATA) and must be completed no later than 60 days after the respective CEMS installation.

(v) The owner or operator of each CEMS must furnish the Regional Administrator a written report of the results of each quarterly performance evaluation and a data accuracy assessment pursuant to 40 CFR part 60 appendix F within 60 days after the calendar quarter in which the performance evaluation was completed. These reports shall be submitted to the Regional Administrator at [email protected].

(vi) The owner or operator of each CEMS must check, record, and quantify the zero and span calibration drifts at least once daily (every 24 hours) in accordance with 40 CFR part 60, appendix F, Procedure 1, Section 4.

(vii) Except for CEMS breakdowns, repairs, calibration checks, and zero and span adjustments, all CEMS required by this section shall be in continuous operation during all periods of BART affected process unit operation, including periods of process unit startup, shutdown, and malfunction.

(viii) All CEMS required by this section must meet the minimum data requirements at paragraphs (c)(4)(viii)(A) through (C) of this section.

(A) Complete a minimum of one cycle of operation (sampling, analyzing, and data recording) for each successive 15-minute quadrant of an hour.

(B) Sample, analyze, and record emissions data for all periods of process operation except as described in paragraph (c)(4)(viii)(C) of this section.

(C) When emission data from CEMS are not available due to continuous monitoring system breakdowns, repairs, calibration checks, or zero and span adjustments, emission data must be obtained using other monitoring systems or emission estimation methods approved by the EPA. The other monitoring systems or emission estimation methods to be used must be incorporated into the monitoring plan required by this section and provide information such that emissions data are available for a minimum of 18 hours in each 24-hour period and at least 22 out of 30 successive unit operating days.

(ix) Owners or operators of each CEMS required by this section must reduce all data to 1-hour averages. Hourly averages shall be computed using all valid data obtained within the hour but no less than one data point in each 15-minute quadrant of an hour. Notwithstanding this requirement, an hourly average may be computed from at least two data points separated by a minimum of 15 minutes (where the unit operates for more than one quadrant in an hour) if data are unavailable as a result of performance of calibration, quality assurance, preventive maintenance activities, or backups of data from data acquisition and handling systems and recertification events.

(x) The 30-day rolling average emission rate determined from data derived from the CEMS required by this section (in lbs/MMBTU or lbs/hr depending on the emission standard selected) must be calculated in accordance with paragraphs (c)(4)(x)(A) through (F) of this section.

(A) Sum the total pounds of the pollutant in question emitted from the unit during an operating day and the previous 29 operating days.

(B) Sum the total heat input to the unit (in MMBTU) or the total actual hours of operation (in hours) during an operating day and the previous 29 operating days.

(C) Divide the total number of pounds of the pollutant in question emitted during the 30 operating days by the total heat input (or actual hours of operation depending on the emission limit selected) during the 30 operating days.

(D) For purposes of this calculation, an operating day is any day during which fuel is combusted in the BART affected unit regardless of whether pellets are produced. Actual hours of operation are the total hours a unit is firing fuel regardless of whether a complete 24-hour operational cycle occurs (i.e. if the furnace is firing fuel for only five hours during a 24-hour period, then the actual operating hours for that day are five. Similarly, total number of pounds of the pollutant in question for that day is determined only from the CEMS data for the five hours during which fuel is combusted.)

(E) If the owner or operator of the CEMS required by this section uses an alternative method to determine 30-day rolling averages, that method must be described in detail in the monitoring plan required by this section. The alternative method will only be applicable if the final monitoring plan and the alternative method are approved by EPA.

(F) A new 30-day rolling average emission rate must be calculated for each new operating day.

(xi) The 720-hour rolling average emission rate determined from data derived from the CEMS required by this section (in lbs/MMBTU) must be calculated in accordance with (c)(4)(xi)(A) through (C).

(A) Sum the total pounds of NOX emitted from the unit every hour and the previous (not necessarily consecutive) 719 hours for which that type of fuel (either natural gas or mixed coal and natural gas) was used.

(B) Sum the total heat input to the unit (in MMBTU) every hour and the previous (not necessarily consecutive) 719 hours for which that type of fuel (either natural gas or mixed coal and natural gas) was used.

(C) Divide the total number of pounds of NOX emitted during the 720 hours, as defined above, by the total heat input during the same 720 hour period. This calculation must be done separately for each fuel type (either for natural gas or mixed coal and natural gas).

(xii) Data substitution must not be used for purposes of determining compliance under this section. If CEMS data is measuring only a portion of the NOX or SO2 emitted during startup, shutdown, or malfunction conditions, the CEMS data may be supplemented, but not modified, by the addition of calculated emission rates using procedures set forth in the site specific monitoring plan.

(xiii) All CEMS data shall be reduced and reported in units of the applicable standard.

(xiv) A Quality Control Program must be developed and implemented for all CEMS required by this section in accordance with 40 CFR part 60, appendix F, Procedure 1, Section 3. The program will include, at a minimum, written procedures and operations for calibration checks, calibration drift adjustments, preventative maintenance, data collection, recording and reporting, accuracy audits/procedures, periodic performance evaluations, and a corrective action program for malfunctioning CEMS.

(d) Recordkeeping requirements. (1)(i) Records required by this section must be kept in a form suitable and readily available for expeditious review.

(ii) Records required by this section must be kept for a minimum of five years following the date of creation.

(iii) Records must be kept on site for at least two years following the date of creation and may be kept offsite, but readily accessible, for the remaining three years.

(2) The owner or operator of the BART affected units must maintain the records at paragraphs (d)(2)(i) through (xi) of this section.

(i) A copy of each notification and report developed for and submitted to comply with this section including all documentation supporting any initial notification or notification of compliance status submitted according to the requirements of this section.

(ii) Records of the occurrence and duration of startup, shutdown, and malfunction of the BART affected units, air pollution control equipment, and CEMS required by this section.

(iii) Records of activities taken during each startup, shutdown, and malfunction of the BART affected unit, air pollution control equipment, and CEMS required by this section.

(iv) Records of the occurrence and duration of all major maintenance conducted on the BART affected units, air pollution control equipment, and CEMS required by this section.

(v) Records of each excess emission report, including all documentation supporting the reports, dates and times when excess emissions occurred, investigations into the causes of excess emissions, actions taken to minimize or eliminate the excess emissions, and preventative measures to avoid the cause of excess emissions from occurring again.

(vi) Records of all CEMS data including, as a minimum, the date, location, and time of sampling or measurement, parameters sampled or measured, and results.

(vii) All records associated with quality assurance and quality control activities on each CEMS as well as other records required by 40 CFR part 60, appendix F, Procedure 1 including, but not limited to, the quality control program, audit results, and reports submitted as required by this section.

(viii) Records of the NOX emissions during all periods of BART affected unit operation, including startup, shutdown, and malfunction in the units of the standard. The owner or operator shall convert the monitored data into the appropriate unit of the emission limitation using appropriate conversion factors and F-factors. F-factors used for purposes of this section shall be documented in the monitoring plan and developed in accordance with 40 CFR part 60, appendix A, Method 19. The owner or operator may use an alternate method to calculate the NOX emissions upon written approval from EPA.

(ix) Records of the SO2 emissions in lbs/MMBTUs or lbs/hr(based on CEMS data), depending on the emission standard selected, during all periods of operation, including periods of startup, shutdown, and malfunction, in the units of the standard.

(x) Records associated with the CEMS unit including type of CEMS, CEMS model number, CEMS serial number, and initial certification of each CEMS conducted in accordance with 40 CFR part 60, appendix B, Performance Specification 2 must be kept for the life of the CEMS unit.

(xi) Records of all periods of fuel oil usage as required at paragraph (b)(2)(vii) of this section.

(e) Reporting requirements. (1) Unless instructed otherwise, all requests, reports, submittals, notifications, and other communications required by this section shall be submitted to the Regional Administrator at [email protected]. References in this section to the Regional Administrator shall mean the EPA Regional Administrator for Region 5.

(2) The owner or operator of each BART affected unit identified in this section and CEMS required by this section must provide to the Regional Administrator the written notifications, reports and plans identified at paragraphs (e)(2)(i) through (viii) of this section.

(i) A notification of the date construction of control devices and installation of burners required by this section commences postmarked no later than 30 days after the commencement date.

(ii) A notification of the date the installation of each CEMS required by this section commences postmarked no later than 30 days after the commencement date.

(iii) A notification of the date the construction of control devices and installation of burners required by this section is complete postmarked no later than 30 days after the completion date.

(iv) A notification of the date the installation of each CEMS required by this section is complete postmarked no later than 30 days after the completion date.

(v) A notification of the date control devices and burners installed by this section startup postmarked no later than 30 days after the startup date.

(vi) A notification of the date CEMS required by this section startup postmarked no later than 30 days after the startup date.

(vii) A notification of the date upon which the initial CEMS performance evaluations are planned. This notification must be submitted at least 60 days before the performance evaluation is scheduled to begin.

(viii) A notification of initial compliance, signed by the responsible official who shall certify its accuracy, attesting to whether the source has complied with the requirements of this section, including, but not limited to, applicable emission standards, control device and burner installations, CEMS installation and certification. This notification must be submitted before the close of business on the 60th calendar day following the completion of the compliance demonstration and must include, at a minimum, the information at paragraphs (e)(2)(viii)(A) through (F) of this section.

(A) The methods used to determine compliance.

(B) The results of any CEMS performance evaluations, and other monitoring procedures or methods that were conducted.

(C) The methods that will be used for determining continuing compliance, including a description of monitoring and reporting requirements and test methods.

(D) The type and quantity of air pollutants emitted by the source, reported in units of the standard.

(E) A description of the air pollution control equipment and burners installed as required by this section, for each emission point.

(F) A statement by the owner or operator as to whether the source has complied with the relevant standards and other requirements.

(3) The owner or operator must develop and implement a written startup, shutdown, and malfunction plan for NOX and SO2. The plan must include, at a minimum, procedures for operating and maintaining the source during periods of startup, shutdown, and malfunction; and a program of corrective action for a malfunctioning process and air pollution control and monitoring equipment used to comply with the relevant standard. The plan must ensure that, at all times, the owner or operator operates and maintains each affected source, including associated air pollution control and monitoring equipment, in a manner which satisfies the general duty to minimize or eliminate emissions using good air pollution control practices. The plan must ensure that owners or operators are prepared to correct malfunctions as soon as practicable after their occurrence.

(4) The written reports of the results of each performance evaluation and QA/QC check in accordance with and as required by paragraph (c)(4)(v) of this section.

(5) Compliance reports. The owner or operator of each BART affected unit must submit semiannual compliance reports. The semiannual compliance reports must be submitted in accordance with paragraphs (e)(5)(i) through (iv) of this section, unless the Administrator has approved a different schedule.

(i) The first compliance report must cover the period beginning on the compliance date that is specified for the affected source through June 30 or December 31, whichever date comes first after the compliance date that is specified for the affected source.

(ii) The first compliance report must be postmarked no later than 30 calendar days after the reporting period covered by that report (July 30 or January 30), whichever comes first.

(iii) 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.

(iv) Each subsequent compliance report must be postmarked no later than 30 calendar days after the reporting period covered by that report (July 30 or January 30).

(6) Compliance report contents. Each compliance report must include the information in paragraphs (e)(6)(i) through (vi) of this section.

(i) Company name and address.

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

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

(iv) Identification of the process unit, control devices, and CEMS covered by the compliance report.

(v) A record of each period of startup, shutdown, or malfunction during the reporting period and a description of the actions the owner or operator took to minimize or eliminate emissions arising as a result of the startup, shutdown or malfunction and whether those actions were or were not consistent with the source's startup, shutdown, and malfunction plan.

(vi) A statement identifying whether there were or were not any deviations from the requirements of this section during the reporting period. If there were deviations from the requirements of this section during the reporting period, then the compliance report must describe in detail the deviations which occurred, the causes of the deviations, actions taken to address the deviations, and procedures put in place to avoid such deviations in the future. If there were no deviations from the requirements of this section during the reporting period, then the compliance report must include a statement that there were no deviations. For purposes of this section, deviations include, but are not limited to, emissions in excess of applicable emission standards established by this section, failure to continuously operate an air pollution control device in accordance with operating requirements designed to assure compliance with emission standards, failure to continuously operate CEMS required by this section, and failure to maintain records or submit reports required by this section.

(7) Each owner or operator of a CEMS required by this section must submit quarterly excess emissions and monitoring system performance reports for each pollutant monitored for each BART affected unit monitored. All reports must be postmarked by the 30th day following the end of each three-month period of a calendar year (January-March, April-June, July-September, October-December) and must include, at a minimum, the requirements at paragraphs (e)(7)(i) through (xv) of this section.

(i) Company name and address.

(ii) Identification and description of the process unit being monitored.

(iii) The dates covered by the reporting period.

(iv) Total source operating hours for the reporting period.

(v) Monitor manufacturer, monitor model number, and monitor serial number.

(vi) Pollutant monitored.

(vii) Emission limitation for the monitored pollutant.

(viii) Date of latest CEMS certification or audit.

(ix) A description of any changes in continuous monitoring systems, processes, or controls since the last reporting period.

(x) A table summarizing the total duration of excess emissions, as defined at paragraphs (e)(7)(x)(A) through (B) of this section, for the reporting period broken down by the cause of those excess emissions (startup/shutdown, control equipment problems, process problems, other known causes, unknown causes), and the total percent of excess emissions (for all causes) for the reporting period calculated as described at paragraph (e)(7)(x)(C) of this section.

(A) For purposes of this section, an excess emission is defined as any 30-day or 720-hour rolling average period, including periods of startup, shutdown, and malfunction, during which the 30-day or 720-hour (as appropriate) rolling average emissions of either regulated pollutant (SO2 and NOX), as measured by a CEMS, exceeds the applicable emission standards in this section.

(B)(1) For purposes of this rule, if a facility calculates a 30-day rolling average emission rate in accordance with this rule which exceeds the applicable emission standards of this rule, then it will be considered 30 days of excess emissions. If the following 30-day rolling average emission rate is calculated and found to exceed the applicable emission standards of this rule as well, then it will add one more day to the total days of excess emissions (i.e. 31 days). Similarly, if an excess emission is calculated for a 30-day rolling average period and no additional excess emissions are calculated until 15 days after the first, then that new excess emission will add 15 days to the total days of excess emissions (i.e. 30 + 15 = 45). For purposes of this section, if an excess emission is calculated for any period of time within a reporting period, there will be no fewer than 30 days of excess emissions but there should be no more than 121 days of excess emissions for a reporting period.

(2) For purposes of this section, if a facility calculates a 720-hour rolling average emission rate in accordance with this rule which exceeds the applicable emission standards of this section, then it will be considered 30 days of excess emissions. If the 24th following 720-hour rolling average emission rate is calculated and found to exceed the applicable emission standards of the rule as well, then it will add one more day to the total days of excess emissions (i.e. 31 days). Similarly, if an excess emission is calculated for a 720-hour rolling average period and no additional excess emissions are calculated until 360 hours after the first, then that new excess emission will add 15 days to the total days of excess emissions (i.e. 30+15 = 45). For purposes of this section, if an excess emission is calculated for any period of time with a reporting period, there will be no fewer than 30 days of excess emissions but there should be no more than 121 days of excess emissions for a reporting period.

(C) For purposes of this section, the total percent of excess emissions will be determined by summing all periods of excess emissions (in days) for the reporting period, dividing that number by the total BART affected unit operating days for the reporting period, and then multiplying by 100 to get the total percent of excess emissions for the reporting period. An operating day, as defined previously, is any day during which fuel is fired in the BART affected unit for any period of time. Because of the possible overlap of 30-day rolling average excess emissions across quarters, there are some situations where the total percent of excess emissions could exceed 100 percent. This extreme situation would only result from serious excess emissions problems where excess emissions occur for nearly every day during a reporting period.

(xi) A table summarizing the total duration of monitor downtime, as defined at paragraph (e)(7)(xi)(A) of this section, for the reporting period broken down by the cause of the monitor downtime (monitor equipment malfunctions, non-monitor equipment malfunctions, quality assurance calibration, other known causes, unknown causes), and the total percent of monitor downtime (for all causes) for the reporting period calculated as described at paragraph (e)(7)(xi)(B) of this section.

(A) For purposes of this section, monitor downtime is defined as any period of time (in hours) during which the required monitoring system was not measuring emissions from the BART affected unit. This includes any period of CEMS QA/QC, daily zero and span checks, and similar activities.

(B) For purposes of this section, the total percent of monitor downtime will be determined by summing all periods of monitor downtime (in hours) for the reporting period, dividing that number by the total number of BART affected unit operating hours for the reporting period, and then multiplying by 100 to get the total percent of excess emissions for the reporting period.

(xii) A table which identifies each period of excess emissions for the reporting period and includes, at a minimum, the information in paragraphs (e)(7)(xii)(A) through (F) of this section.

(A) The date of each excess emission.

(B) The beginning and end time of each excess emission.

(C) The pollutant for which an excess emission occurred.

(D) The magnitude of the excess emission.

(E) The cause of the excess emission.

(F) The corrective action taken or preventative measures adopted to minimize or eliminate the excess emissions and prevent such excess emission from occurring again.

(xiii) A table which identifies each period of monitor downtime for the reporting period and includes, at a minimum, the information in paragraphs (e)(7)(xiii)(A) through (D) of this section.

(A) The date of each period of monitor downtime.

(B) The beginning and end time of each period of monitor downtime.

(C) The cause of the period of monitor downtime.

(D) The corrective action taken or preventative measures adopted for system repairs or adjustments to minimize or eliminate monitor downtime and prevent such downtime from occurring again.

(xiv) If there were no periods of excess emissions during the reporting period, then the excess emission report must include a statement which says there were no periods of excess emissions during this reporting period.

(xv) If there were no periods of monitor downtime, except for daily zero and span checks, during the reporting period, then the excess emission report must include a statement which says there were no periods of monitor downtime during this reporting period except for the daily zero and span checks.

(8) The owner or operator of each CEMS required by this section must develop and submit for review and approval by the Regional Administrator a site specific monitoring plan. The purpose of this monitoring plan is to establish procedures and practices which will be implemented by the owner or operator in its effort to comply with the monitoring, recordkeeping, and reporting requirements of this section. The monitoring plan must include, at a minimum, the information at paragraphs (e)(8)(i) through (x) of this section.

(i) Site specific information including the company name, address, and contact information.

(ii) The objectives of the monitoring program implemented and information describing how those objectives will be met.

(iii) Information on any emission factors used in conjunction with the CEMS required by this section to calculate emission rates and a description of how those emission factors were determined.

(iv) A description of methods to be used to calculate emission rates when CEMS data are not available due to downtime associated with QA/QC events.

(v) A description of the QA/QC program to be implemented by the owner or operator of CEMS required by this section. This can be the QA/QC program developed in accordance with 40 CFR part 60, appendix F, Procedure 1, Section 3.

(vi) A list of spare parts for CEMS maintained on site for system maintenance and repairs.

(vii) A description of the procedures to be used to calculate 30-day rolling averages and 720-hour rolling averages and example calculations which show the algorithms used by the CEMS to calculate 30-day rolling averages and 720-hour rolling averages.

(viii) A sample of the document to be used for the quarterly excess emission reports required by this section.

(ix) A description of the procedures to be implemented to investigate root causes of excess emissions and monitor downtime and the proposed corrective actions to address potential root causes of excess emissions and monitor downtime.

(x) A description of the sampling and calculation methodology for determining the percent sulfur by weight as a monthly block average for coal used during that month.

(f) Equations for establishing the upper predictive limit—(1) Equation for normal distribution and statistically independent data.

Where: x = average or mean of hourly test run data; t[(n−1),(0.99)] = t score, the one-tailed t value of the Student's t distribution for a specific degree of freedom (n−1) and a confidence level (0.99, to reflect the 99th percentile) s 2 = variance of the hourly data set; n = number of values (e.g., 5,760 if 8 months of valid lbs NOX/MMBTU hourly values) m = number of values used to calculate the test average (m = 720 as per averaging time)

(i) To determine if statistically independent, use the Rank von Neumann Test on p. 137 of data Quality Assessment: Statistical Methods for Practitioners EPA QA/G-9S.

(ii) Alternative to Rank von Neumann test to determine if data are dependent, data are dependent if t test value is greater than t critical value, where:

ρ = correlation between data points t critical = t[(n−2),(0.95)] = t score, the two-tailed t value of the Student's t Distribution for a specific degree of freedom (n−2) and a confidence level (0.95)

(iii) The Anderson-Darling normality test is used to establish whether the data are normally distributed. That is, a distribution is considered to be normally distributed when p > 0.05.

(2) Non-parametric equation for data not normally distributed and normally distributed but not statistically independent.

m = (n+1) * α m = the rank of the ordered data point, when data are sorted smallest to largest. The data points are 720-hour averages for establishing NOX limits. n = number of data points (e.g., 5,040 720-hourly averages for eight months of valid NOX lbs/MMBTU values) α = 0.99, to reflect the 99th percentile

If m is a whole number, then the limit, UPL, shall be computed as:

UPL = Xm Where: Xm = value of the mth data point in terms of lbs SO2/hr or lbs NOX/MMBtu, when the data are sorted smallest to largest.

If m is not a whole number, the limit shall be computed by linear interpolation according to the following equation.

UPL = xm = xmi.md = xmi + 0.md(xm(i+1)−xmi) Where: mi = the integer portion of m, i.e., m truncated at zero decimal places, and md = the decimal portion of m [78 FR 8738, Feb. 6, 2013, as amended at 81 FR 21687, Apr. 12, 2016; 86 FR 12106, Mar. 2, 2021; 91 FR 50, Jan. 2, 2026]