Wis. Admin. Code Department of Natural Resources NR 463.26

Current through October 28, 2024
Section NR 463.26 - Continuous compliance requirements
(1) WHAT ARE MY MONITORING REQUIREMENTS?
(a) For each capture system subject to an operating limit in s. NR 463.23(1) (b) 1., you shall install, operate and maintain a CPMS according to the requirements in sub. (2) (a) and both of the following requirements, as applicable:
1. If you use a flow measurement device to monitor the operating limit parameter, you shall at all times monitor the hourly average rate.

Note: For example, the hourly average actual volumetric flow rate through each separately ducted hood or the average hourly total volumetric flow rate at the inlet to the control device.

2. For dampers that are not manually set and remain in the same position, you shall make a visual check at least once every 24 hours to verify that each damper for the capture system is in the same position as during the initial performance test. Dampers that are manually set and remain in the same position are exempt from the requirement to install and operate a CPMS.
(b) For each negative pressure baghouse or positive pressure baghouse equipped with a stack that is applied to meet any PM or total metal HAP emissions limitation in this subchapter, you shall at all times monitor the relative change in PM loadings using a bag leak detection system according to the requirements in sub. (2) (b) and do all of the following:
1. Monitor the pressure drop across each baghouse cell each day to ensure pressure drop is within the normal operating range identified in the manual.
2. Confirm that dust is being removed from hoppers through weekly visual inspections or other means of ensuring the proper functioning of removal mechanisms.
3. Check the compressed air supply for pulse-jet baghouses each day.
4. Monitor cleaning cycles to ensure proper operation using an appropriate methodology.
5. Check bag cleaning mechanisms for proper functioning through monthly visual inspection or equivalent means.
6. Make monthly visual checks of bag tension on reverse air and shaker-type baghouses to ensure that bags are not kinked, kneed or bent, or lying on their sides. You do not have to make this check for shaker-type baghouses using self-tensioning, spring-loaded, devices.
7. Confirm the physical integrity of the baghouse through quarterly visual inspections of the baghouse interior for air leaks.
8. Inspect fans for wear, material buildup and corrosion through quarterly visual inspections, vibration detectors or equivalent means.
(c) For each wet scrubber subject to the operating limits in s. NR 463.23(1) (b) 2., you shall at all times monitor the 3-hour average pressure drop and scrubber water flow rate using CPMS according to the requirements in sub. (2) (c).
(d) For each combustion device subject to the operating limit in s. NR 463.23(1) (b) 3., you shall at all times monitor the 15-minute average combustion zone temperature using a CPMS according to the requirements of sub. (2) (d).
(e) For each combustion device subject to the operating limit in s. NR 463.23(1) (b) 4., you shall at all times monitor the 3-hour average combustion zone temperature using CPMS according to the requirements in sub. (2) (d).
(f) For each wet acid scrubber subject to the operating limits in s. NR 463.23(1) (b) 5., you shall do both of the following at all times:
1. Monitor the 3-hour average scrubbing liquid flow rate using CPMS according to the requirements of sub. (2) (e) 1.
2. Monitor the 3-hour average pH of the scrubber blowdown using CPMS according to the requirements in sub. (2) (e) 1., or measure and record the pH of the scrubber blowdown once per production cycle using a pH probe and meter according to the requirements in sub. (2) (e) 2.
(g) For one or more automated conveyor and pallet cooling lines and automated shakeout lines at a new iron and steel foundry subject to the VOHAP emissions limit in s. NR 463.23(1) (a) 10., you shall at all times monitor the 3-hour average VOHAP concentration using a CEMS according to the requirements of sub. (2) (g).
(2) WHAT ARE THE INSTALLATION, OPERATION AND MAINTENANCE REQUIREMENTS FOR MY MONITORS?
(a) For each capture system subject to an operating limit in s. NR 463.23(1) (b) 1., you shall install, operate and maintain each CPMS according to the following requirements, as applicable:
1. If you use a flow measurement device to monitor an operating limit parameter for a capture system, you shall do all of the following:
a. Locate the flow sensor and other necessary equipment, such as straightening vanes, in a position that provides a representative flow and that reduces swirling flow or abnormal velocity distributions due to upstream and downstream disturbances.
b. Use a flow sensor with a minimum measurement sensitivity of 2% of the flow rate.
c. Conduct a flow sensor calibration check at least semiannually.
d. At least monthly, inspect all components for integrity, all electrical connections for continuity and all mechanical connections for leakage.
e. Record the results of each inspection, calibration and validation check required under this subdivision.
2. If you use a pressure measurement device to monitor the operating limit parameter for a capture system, you shall do all of the following:
a. Locate the pressure sensors in, or as close as possible, to a position that provides a representative measurement of the pressure and that minimizes or eliminates pulsating pressure, vibration, and internal and external corrosion.
b. Use a gauge with a minimum measurement sensitivity of 0.5 inch of water or a transducer with a minimum measurement sensitivity of one percent of the pressure range.
c. Check the pressure tap for blockage or plugging daily.
d. Using a manometer, check gauge calibration quarterly and transducer calibration monthly.
e. Conduct calibration checks any time the sensor exceeds the manufacturer's specified maximum operating pressure range or install a new pressure sensor.
f. At least monthly, inspect all components for integrity, all electrical connections for continuity and all mechanical connections for leakage.
g. Record the results of each inspection, calibration and validation check required under this subdivision.
(b) You shall install, operate and maintain a bag leak detection system according to all of the following requirements:
1. The system shall be certified by the manufacturer to be capable of detecting emissions of particulate matter at concentrations of 10 milligrams per actual cubic meter (0.0044 grains per actual cubic foot) or less.
2. The bag leak detection system sensor shall provide output of relative particulate matter loadings, and the owner or operator shall continuously record the output from the bag leak detection system using electronic or other means such as a strip chart recorder or a data logger.
3. The system shall be equipped with an alarm that will sound when an increase in relative particulate loadings is detected over the alarm set point established in the operation and maintenance plan. The alarm shall be located such that it can be heard by the appropriate plant personnel.
4. The initial adjustment of the system shall, at a minimum, consist of establishing the baseline output by adjusting the sensitivity or range and the averaging period of the device and establishing the alarm set points and the alarm delay time, if applicable.
5. Following the initial adjustment, the sensitivity or range, averaging period, alarm set point or alarm delay time may not be adjusted without approval from the department. Except, once per quarter, you may adjust the sensitivity of the bag leak detection system to account for seasonal effects, including temperature and humidity, according to the procedures in the operation and maintenance plan required by s. NR 463.23(3) (b).
6. For negative pressure induced air baghouses and positive pressure baghouses that are discharged to the atmosphere through a stack, the bag leak detector sensor shall be installed downstream of the baghouse and upstream of any wet scrubber.
7. Where multiple detectors are required, the system's instrumentation and alarm may be shared among detectors.
(c) For each wet scrubber subject to the operating limits in s. NR 463.23(1) (b) 2., you shall install and maintain CPMS to measure and record the pressure drop and scrubber water flow rate according to the requirements in subds. 1. and 2.:
1. For each CPMS for pressure drop, you shall do all of the following:
a. Locate the pressure sensor in, or as close as possible to, a position that provides a representative measurement of the pressure drop and that minimizes or eliminates pulsating pressure, vibration and internal and external corrosion.
b. Use a gauge with a minimum measurement sensitivity of 0.5 inch of water or a transducer with a minimum measurement sensitivity of one percent of the pressure range.
c. Check the pressure tap for blockage or plugging daily.
d. Using a manometer, check gauge calibration quarterly and transducer calibration monthly.
e. Conduct calibration checks any time the sensor exceeds the manufacturer's specified maximum operating pressure range or install a new pressure sensor.
f. At least monthly, inspect all components for integrity, all electrical connections for continuity and all mechanical connections for leakage.
2. For each CPMS for scrubber liquid flow rate, you shall do all of the following:
a. Locate the flow sensor and other necessary equipment in a position that provides a representative flow and that reduces swirling flow or abnormal velocity distributions due to upstream and downstream disturbances.
b. Use a flow sensor with a minimum measurement sensitivity of 2% of the flow rate.
c. Conduct a flow sensor calibration check at least semiannually according to the manufacturer's instructions.
d. At least monthly, inspect all components for integrity, all electrical connections for continuity and all mechanical connections for leakage.
(d) For each combustion device subject to the operating limit in s. NR 463.23(1) (b) 3. or 4., you shall install and maintain a CPMS to measure and record the combustion zone temperature according to the following requirements, as applicable:
1. Locate the temperature sensor in a position that provides a representative temperature.
2. For a non-cryogenic temperature range, use a temperature sensor with a minimum tolerance of 2.2°C or 0.75% of the temperature value, whichever is larger.
3. For a cryogenic temperature range, use a temperature sensor with a minimum tolerance of 2.2°C or 2% of the temperature value, whichever is larger.
4. Shield the temperature sensor system from electromagnetic interference and chemical contaminants.
5. If you use a chart recorder, it shall have a sensitivity in the minor division of at least 20°F.
6. Perform an electronic calibration at least semiannually according to the procedures in the manufacturer's owners manual. Following the electronic calibration, conduct a temperature sensor validation check, in which a second or redundant temperature sensor placed nearby the process temperature sensor shall yield a reading within 16.7°C of the process temperature sensor's reading.
7. Conduct calibration and validation checks any time the sensor indicates a temperature that exceeds the manufacturer's specified maximum operating temperature range, or install a new temperature sensor.
8. At least monthly, inspect all components for integrity and all electrical connections for continuity, oxidation and galvanic corrosion.
(e) For each wet acid scrubber subject to the operating limits in s. NR 463.23(1) (b) 5., you shall install and maintain CPMS to measure and record the scrubbing liquid flow rate according to the requirements in par. (c) 2. and do either of the following:
1. Install and maintain CPMS to measure and record the pH of the scrubber blowdown according to all of the following requirements:
a. Locate the pH sensor in a position that provides a representative measurement of the pH and that minimizes or eliminates internal and external corrosion.
b. Use a gauge with a minimum measurement sensitivity of 0.1 pH unit or a transducer with a minimum measurement sensitivity of 5% of the pH range.
c. Check gauge calibration quarterly or transducer calibration monthly using a manual pH gauge.
d. At least monthly, inspect all components for integrity, all electrical connections for continuity and all mechanical connections for leakage.
2. Extract a sample for analysis by a pH meter that has all of the following:
a. A range of at least 1 to 5 pH units or more.
b. An accuracy of 0.1 pH unit.
c. A resolution of at least 0.1 pH unit.
(f) You shall operate each CPMS used to meet the requirements of this subchapter according to all of the following requirements:
1. Each CPMS shall complete a minimum of one cycle of operation for each successive 15-minute period. You shall have a minimum of 3 of the required 4 data points to constitute a valid hour of data.
2. Each CPMS shall have valid hourly data for 100% of every averaging period.
3. Each CPMS shall calculate and record the hourly average of all recorded readings and the 3-hour average of all recorded readings.
(g) For each automated conveyor and pallet cooling line and automated shakeout line at a new iron and steel foundry subject to the VOHAP emission limit in s. NR 463.23(1) (a) 10., you shall install, operate and maintain a CEMS to measure and record the concentration of VOHAP emissions according to all of the following requirements:
1. You shall install, operate and maintain each CEMS according to performance specification 8 in 40 CFR part 60, Appendix B, incorporated by reference in s. NR 484.04(21).
2. You shall conduct a performance evaluation of each CEMS according to the requirements of s. NR 460.07 and performance specification 8 in 40 CFR part 60, Appendix B.
3. As specified in s. NR 460.07(3) (d) 2., each CEMS shall complete a minimum of one cycle of operation, which includes sampling, analyzing and data recording, for each successive 15-minute period.
4. You shall reduce CEMS data as specified in s. NR 460.07(7) (b).
5. Each CEMS shall calculate and record the 3-hour average emissions using all the hourly averages collected for periods during which the CEMS is not out-of-control.
6. You shall record the results of each inspection, calibration and validation check required under this paragraph.
(3) HOW DO I MONITOR AND COLLECT DATA TO DEMONSTRATE CONTINUOUS COMPLIANCE?
(a) Except for monitoring malfunctions, associated repairs and required quality assurance or control activities, including, as applicable, calibration checks and required zero and span adjustments, you shall monitor continuously or collect data at all required intervals any time a source of emissions is operating.
(b) 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 emissions or operating levels or to fulfill a minimum data availability requirement, if applicable. You shall use all the data collected during all other periods in assessing compliance.
(4) HOW DO I DEMONSTRATE CONTINUOUS COMPLIANCE WITH THE EMISSION LIMITATIONS THAT APPLY TO ME?
(a) You shall demonstrate continuous compliance by meeting the following requirements, as applicable:
1. For each electric arc metal melting furnace, electric induction metal melting furnace or scrap preheater at an existing iron and steel foundry, you shall do one of the following:
a. Maintain the average PM concentration in the exhaust stream at or below 0.005 gr/dscf.
b. Maintain the average total metal HAP concentration in the exhaust stream at or below 0.0004 gr/dscf.
2. For each cupola metal melting furnace at an existing iron and steel foundry, you shall do one of the following:
a. Maintain the average PM concentration in the exhaust stream at or below 0.006 gr/dscf.
b. Maintain the average total metal HAP concentration in the exhaust stream at or below 0.0005 gr/dscf.
3. For each cupola metal melting furnace or electric arc metal melting furnace at new iron and steel foundry, you shall do one of the following:
a. Maintain the average PM concentration in the exhaust stream at or below 0.002 gr/dscf.
b. Maintain the average total metal HAP concentration in the exhaust stream at or below 0.0002 gr/dscf.
4. For each electric induction metal melting furnace or scrap preheater at a new iron and steel foundry, you shall do one of the following:
a. Maintain the average PM concentration in the exhaust stream at or below 0.001 gr/dscf.
b. Maintain the average total metal HAP concentration in the exhaust stream at or below 0.00008 gr/dscf.
5. For each pouring station at an existing iron and steel foundry, you shall do one of the following:
a. Maintain the average PM concentration in the exhaust stream at or below 0.010 gr/dscf.
b. Maintain the average total metal HAP concentration in the exhaust stream at or below 0.0008 gr/dscf.
6. For each pouring area or pouring station at a new iron and steel foundry, you shall do one of the following:
a. Maintain the average PM concentration in the exhaust stream at or below 0.002 gr/dscf.
b. Maintain the average total metal HAP concentration in the exhaust stream at or below 0.0002 gr/dscf.
7. For each building or structure housing any emission source at the iron and steel foundry, you shall maintain the opacity of any fugitive emissions discharged to the atmosphere at or below 20% opacity (6-minute average), except for one 6-minute average per hour that does not exceed 27% opacity.
8. For each cupola metal melting furnace at a new or existing iron and steel foundry, you shall maintain the average VOHAP concentration in the exhaust stream at or below 20 ppmv corrected to 10% oxygen.
9. For each scrap preheater at an existing iron and steel foundry that does not comply with the work practice standard in s. NR 463.23(2) (e) 1. or 2. and for each scrap preheater at a new iron and steel foundry that does not comply with the work practice standard in s. NR 463.23(2) (f), you shall maintain the average VOHAP concentration in the exhaust stream at or below 20 ppmv.
10. For one or more automated conveyor and pallet cooling lines or automated shakeout lines that use a sand mold system at a new iron and steel foundry, you shall do all of the following:
a. Maintain the 3-hour flow-weighted average VOHAP concentration in the exhaust stream at or below 20 ppmv.
b. Inspect and maintain each CEMS according to the requirements of sub. (2) (g) and record all information needed to document conformance with these requirements.
c. Collect and reduce monitoring data according to the requirements of sub. (2) (g) and record all information needed to document conformance with these requirements.
11. For each TEA cold box mold or core making line at a new or existing iron and steel foundry, you shall maintain a 99% reduction in the VOHAP concentration in the exhaust stream or maintain the average VOHAP concentration in the exhaust stream at or below 1 ppmv.
12. You shall conduct subsequent performance tests at least every 5 years for each emission source subject to an emission limit for PM, total metal HAP, VOHAP or TEA in s. NR 463.23(1) (a) and subsequent performance tests at least every 6 months for each building or structure subject to the opacity limit in s. NR 463.23(1) (a) 7.
(b) You shall demonstrate continuous compliance for each capture system subject to an operating limit in s. NR 463.23(1) (b) 1. by doing both of the following:
1. Operate the capture system at or above the lowest values or settings established for the operating limits in your operation and maintenance plan.
2. Monitor the capture system according to the requirements in sub. (1) (a) and collect, reduce and record the monitoring data for each of the operating limit parameters according to the applicable requirements in this subchapter.
(c) You shall demonstrate continuous compliance for each baghouse equipped with a bag leak detection system doing both of the following:
1. Maintain records of the times the bag leak detection system alarm sounded, and for each valid alarm, the time you initiated corrective action, the corrective action taken and the date on which corrective action was completed.
2. Inspect and maintain each baghouse according to the requirements of sub. (1) (b) 1. to 8., and record all information needed to document conformance with these requirements.
(d) You shall demonstrate continuous compliance for each wet scrubber that is subject to the operating limits in s. NR 463.23(1) (b) 2., by doing all of the following:
1. Maintaining the 3-hour average pressure drop and 3-hour average scrubber water flow rate at levels no lower than those established during the initial or subsequent performance test.
2. Inspecting and maintaining each CPMS according to the requirements of sub. (2) (c) and recording all information needed to document conformance with the requirements.
3. Collecting and reducing monitoring data for pressure drop and scrubber water flow rate according to the requirements of sub. (2) (f) and recording all information needed to document conformance with the requirements.
(e) You shall demonstrate continuous compliance for each combustion device that is subject to the operating limit in s. NR 463.23(1) (b) 3., by doing all of the following:
1. Maintaining the 15-minute average combustion zone temperature at a level no lower than 1,300°F.
2. Inspecting and maintaining each CPMS according to the requirements of sub. (2) (d) and recording all information needed to document conformance with the requirements.
3. Collecting and reducing monitoring data for combustion zone temperature according to the requirements of sub. (2) (f) and recording all information needed to document conformance with the requirements.
(f) You shall demonstrate continuous compliance for each combustion device that is subject to the operating limit in s. NR 463.23(1) (b) 4., by doing all of the following:
1. Maintaining the 3-hour average combustion zone temperature at a level no lower than that established during the initial or subsequent performance test.
2. Inspecting and maintaining each CPMS according to the requirements of sub. (2) (d) and recording all information needed to document conformance with these requirements.
3. Collecting and reducing monitoring data for combustion zone temperature according to the requirements of sub. (2) (f) and recording all information needed to document conformance with these requirements.
(g) You shall demonstrate continuous compliance for each acid wet scrubber subject to the operating limits in s. NR 463.23(1) (b) 5., by doing all of the following:
1. Maintaining the 3-hour average scrubbing liquid flow rate at a level no lower than the level established during the initial or subsequent performance test.
2. Maintaining the 3-hour average pH of the scrubber blowdown at a level no higher than 4.5, if measured by a CPMS, or maintaining the pH level of the scrubber blowdown during each production shift no higher than 4.5.
3. Inspecting and maintaining each CPMS according to the requirements of sub. (2) (e) and recording all information needed to document conformance with the requirements.
4. Collecting and reducing monitoring data for scrubbing liquid flow rate and scrubber blowdown pH according to the requirements of sub. (2) (f) and recording all information needed to document conformance with the requirements. If the pH level of the scrubber blowdown is measured by a probe and meter, you shall demonstrate continuous compliance by maintaining records that document the date, time and results of each sample taken for each production shift.
(5) HOW DO I DEMONSTRATE CONTINUOUS COMPLIANCE WITH THE WORK PRACTICE STANDARDS THAT APPLY TO ME?
(a) You shall maintain records that document continuous compliance with the certification requirements in s. NR 463.23(2) (b) or with the procedures in your scrap selection and inspection plan required in s. NR 463.23(2) (c). Your records documenting compliance with the scrap selection and inspection plan shall include a copy kept onsite of the procedures used by the scrap supplier for either removing accessible mercury switches or for purchasing automobile bodies that have had mercury switches removed, as applicable.
(b) You shall keep records of the chemical composition of all catalyst binder formulations applied in each furan warm box mold or core making line at a new or existing iron and steel foundry to demonstrate continuous compliance with the requirements in s. NR 463.23(2) (d).
(c) For a scrap preheater at an existing iron and steel foundry, you shall operate and maintain each gas-fired preheater so that the flame directly contacts the scrap charged to demonstrate continuous compliance with the requirement s. NR 463.23(2) (e) 1. If you choose to meet the work practice standard in s. NR 463.23(2) (e) 2., you shall keep records to document that the scrap preheater charges only material that is subject to and in compliance with the scrap certification requirements in s. NR 463.23(2) (b).
(d) For a scrap preheater at a new iron and steel foundry, you shall keep records to document that each scrap preheater charges only material that is subject to and in compliance with the scrap certification requirements in s. NR 463.23(2) (b) to demonstrate continuous compliance with the requirement in s. NR 463.23(2) (f).
(6) HOW DO I DEMONSTRATE CONTINUOUS COMPLIANCE WITH THE OPERATION AND MAINTENANCE REQUIREMENTS THAT APPLY TO ME?
(a) For each capture system and control device for an emission source subject to an emission limit in s. NR 463.23(1) (a), you shall demonstrate continuous compliance with the operation and maintenance requirements of s. NR 463.23(3) by doing all of the following:
1. Making monthly inspections of capture systems and initiating corrective action according to s. NR 463.23(3) (b) 1., and recording all information needed to document conformance with the requirements.
2. Performing preventive maintenance for each control device according to the preventive maintenance plan required by s. NR 463.23(3) (b) 3., and recording all information needed to document conformance with the requirements.
3. Operating and maintaining each bag leak detection system according to the site-specific monitoring plan required by s. NR 463.23(3) (b) 4., and recording all information needed to demonstrate conformance with the requirements.
4. Initiating and completing corrective action for a bag leak detection system alarm according to the corrective action plan required by s. NR 463.23(3) (b) 5., and recording all information needed to document conformance with the requirements.
5. Igniting gases from mold vents according to the procedures in the plan required by s. NR 463.23(3) (b) 6.
(b) Any instance where you fail to follow the procedures in par. (a) is a deviation that shall be included in your semiannual compliance report.
(c) You shall maintain a current copy of the operation and maintenance plans required by s. NR 463.23(3) (b) onsite and available for inspection upon request. You shall keep the plans for the life of the iron and steel foundry or until the iron and steel foundry is no longer subject to the requirements of this subchapter.
(7) WHAT OTHER REQUIREMENTS MUST I MEET TO DEMONSTRATE CONTINUOUS COMPLIANCE?
(a) Deviations. You shall report each instance in which you did not meet each emission limitation in s. NR 463.23(1), including each operating limit, that applies to you. This requirement includes periods of startup, shutdown and malfunction. You also shall report each instance in which you did not meet each work practice standard in s. NR 463.23(2) and each operation and maintenance requirement of s. NR 463.23(3) that applies to you. Failure to meet the requirements described in this paragraph are deviations from the emission limitations, work practice standards and operation and maintenance requirements in this subchapter and shall be reported according to the requirements of s. NR 463.27(2).
(b) Startups, shutdowns and malfunctions.
1. Consistent with the requirements of ss. NR 460.05(4) and 460.06(4) (a), deviations that occur during a period of startup, shutdown or malfunction are not violations if you demonstrate to the department's satisfaction that you were operating in accordance with s. NR 460.05(4) (a).
2. The department shall determine whether deviations that occur during a period of startup, shutdown or malfunction are violations according to the provisions in s. NR 460.05(4).
(8) HOW DO I APPLY FOR ALTERNATIVE MONITORING REQUIREMENTS FOR A CONTINUOUS EMISSIONS MONITORING SYSTEM?
(a) You may submit a request to the administrator for an alternative monitoring method to demonstrate compliance with the VOHAP emission limits in s. NR 463.23(1) (a) 10. for automated pallet cooling lines or automated shakeout lines at a new iron and steel foundry according to the procedures in this section.
(b) You may request approval to use an alternative monitoring method in the notification of construction or for new sources, or at any time.
(c) You shall submit a monitoring plan to the administrator that includes a description of the control technique or pollution prevention technique, a description of the continuous monitoring system or method, including appropriate operating parameters that will be monitored, test results demonstrating compliance with the emission limit, operating limits, if applicable, determined according to the test results, and the frequency of measuring and recording to establish continuous compliance. If applicable, you shall also include operation and maintenance requirements for the monitors.
(d) The monitoring plan is subject to approval by the administrator. Use of the alternative monitoring method may not begin until approval is granted by the administrator.

Wis. Admin. Code Department of Natural Resources NR 463.26

CR 06-110: cr. Register July 2007 No. 619, eff. 8-1-07.

The Administrator of the US Environmental Protection Agency retains the authority to approve major alternatives to monitoring according to 40 CFR 63.7761(c) (3).