For each source as defined in § 63.101, and for each source as defined in § 63.191, beginning no later than the compliance dates specified in § 63.100(k)(12), the owner or operator must conduct sampling along the facility property boundary and analyze the samples in accordance with paragraphs (a) through (i) of this section. Sampling of benzene, 1,3-butadiene, chloroprene, and ethylene dichloride must be conducted in accordance with paragraph (a) of this section. Sampling of ethylene oxide and vinyl chloride must be conducted in accordance with paragraph (b) of this section. Paragraphs (c) through (i) of this section apply for any compound required to be sampled.

(a) The owner or operator must conduct sampling along the facility property boundary and analyze the samples in accordance with Methods 325A and 325B of appendix A to this part and paragraphs (a)(1) through (3) of this section. The monitoring perimeter may be located inside the facility, away from the facility property boundary. However, the monitoring perimeter must encompass all potential sources of the target analyte(s) specified in paragraph (a)(1) of this section that are located within the facility's property boundary.

(1) The owner or operator must monitor the target analyte(s), as specified in paragraphs (a)(1)(i) through (iv) of this section. The owner or operator must follow the procedure in Section 9.6 of Method 325B of appendix A to this part to determine the detection limit of benzene, 1,3-butadiene, chloroprene, and ethylene dichloride for each sampler used to collect samples and blanks.

(i) If an affected source uses, produces, stores, or emits benzene, the owner or operator must include benzene as a target analyte.

(ii) If an affected source uses, produces, stores, or emits 1,3-butadiene, the owner or operator must include 1,3-butadiene as a target analyte.

(iii) If an affected source uses, produces, stores, or emits chloroprene, the owner or operator must include chloroprene as a target analyte.

(iv) If an affected source uses, produces, stores, or emits ethylene dichloride, the owner or operator must include ethylene dichloride as a target analyte.

(2) The owner or operator must determine passive monitor locations in accordance with Section 8.2 of Method 325A of appendix A to this part.

(i) As it pertains to this subpart, known sources of VOCs, as used in Section 8.2.1.3 in Method 325A of appendix A to this part for siting passive monitors, means a wastewater treatment unit, process unit, or any emission source requiring control according to the requirements of this subpart, including marine vessel loading operations. For marine vessel loading operations, one passive monitor should be sited on the shoreline adjacent to the dock. For this subpart, an additional monitor is not required if the only emission sources within 50 meters of the monitoring boundary are equipment leak sources satisfying all of the conditions in paragraphs (a)(2)(i)(A) through (C) of this section. If a leak is found, it must be repaired no later than 15 calendar days after it is detected with no provisions for delay of repair. If a repair is not completed within 15 calendar days, the additional passive monitor specified in Section 8.2.1.3 in Method 325A of appendix A to this part must be used.

(A) The equipment leak sources in organic HAP service within 50 meters of the monitoring boundary are limited to valves, pumps, connectors, sampling connections, and open-ended lines. If compressors, pressure relief devices, or agitators in organic HAP service are present within 50 meters of the monitoring boundary, the additional passive monitoring location specified in Section 8.2.1.3 in Method 325A of appendix A to this part must be used.

(B) All equipment leak sources in gas or light liquid service (and in organic HAP service), including valves, pumps, connectors, sampling connections and open-ended lines, must be monitored using Method 21 of appendix A-7 to 40 CFR part 60 no less frequently than quarterly with no provisions for skip period monitoring, or according to the provisions of § 63.11(c) Alternative Work practice for monitoring equipment for leaks. For the purpose of this provision, a leak is detected if the instrument reading equals or exceeds the applicable limits in paragraphs (a)(2)(i)(B)(1) through (5) of this section:

(1) For valves, pumps or connectors at an existing source, an instrument reading of 10,000 ppmv.

(2) For valves or connectors at a new source, an instrument reading of 500 ppmv.

(3) For pumps at a new source, an instrument reading of 2,000 ppmv.

(4) For sampling connections or open-ended lines, an instrument reading of 500 ppmv above background.

(5) For equipment monitored according to the Alternative Work practice for monitoring equipment for leaks, the leak definitions contained in § 63.11(c)(6)(i) through (iii).

(C) All equipment leak sources in organic HAP service, including sources in gas, light liquid and heavy liquid service, must be inspected using visual, audible, olfactory, or any other detection method at least monthly. A leak is detected if the inspection identifies a potential leak to the atmosphere or if there are indications of liquids dripping.

(ii) If there are 19 or fewer monitoring locations, the owner or operator must collect at least one co-located duplicate sample per sampling period and at least one field blank per sampling period. If there are 20 or more monitoring locations, the owner or operator must collect at least two co-located duplicate samples per sampling period and at least one field blank per sampling period. The co-located duplicates may be collected at any of the perimeter sampling.

(iii) Samplers are not required to be placed along internal roads, waterways, or other right of ways that may bisect the facility. If a facility is bounded by a waterway on one or more sides, the shoreline is considered the facility property boundary.

(3) The owner or operator must use a sampling period and sampling frequency as specified in paragraphs (a)(3)(i) through (iii) of this section.

(i) Sampling period. A 14-day sampling period must be used, unless a shorter sampling period is determined to be necessary under paragraph (e) or (g) of this section. A sampling period is defined as the period during which sampling tube is deployed at a specific sampling location with the diffusive sampling end cap in-place and does not include the time required to analyze the sample. For the purpose of this subpart, a 14-day sampling period may be no shorter than 13 calendar days and no longer than 15 calendar days, but the routine sampling period must be 14 calendar days.

(ii) Base sampling frequency. Except as provided in paragraph (a)(3)(iii) of this section, the frequency of sample collection must be once each contiguous 14-day sampling period, such that the beginning of the next 14-day sampling period begins immediately upon the completion of the previous 14-day sampling period.

(iii) Alternative sampling frequency for burden reduction. When an individual monitor consistently achieves results for a particular analyte at or below the level specified in paragraph (a)(4) of this section, the owner or operator may elect to use the applicable minimum sampling frequency specified in paragraphs (a)(3)(iii)(A) through (E) of this section for that monitoring site for that analyte. When calculating Δc for the monitoring period when using this alternative for burden reduction, use zero for the lowest sampling result for each monitoring period where one or more samples was not taken and/or analyzed for the analyte(s) that qualifies for this alternative sampling frequency. This alternative for burden reduction is determined on an analyte specific basis. If an owner or operator is not required to sample for a particular analyte for a particular monitoring site in accordance with this paragraph (a)(3)(iii), the owner or operator must still sample for any other analytes required by paragraph (a)(1) of this section at the frequency specified in paragraph (a)(3)(ii) of this section, unless the other analyte(s) also qualifies for this alternative for burden reduction.

(A) For the analyte of interest, if every sample at a monitoring site is at or below the level specified in paragraph (a)(4) of this section for 2 years (52 consecutive samples), every other sampling period can be skipped for that analyte for that monitoring site, i.e., sampling will occur approximately once per month.

(B) For the analyte of interest, if every sample at a monitoring site that is monitored at the frequency specified in paragraph (a)(3)(iii)(A) of this section is at or below the level specified in paragraph (a)(4) of this section for 2 years (i.e., 26 consecutive “monthly” samples), five 14-day sampling periods can be skipped for that analyte for that monitoring site following each period of sampling, i.e., sampling will occur approximately once per quarter.

(C) For the analyte of interest, if every sample at a monitoring site that is monitored at the frequency specified in paragraph (a)(3)(iii)(B) of this section is at or below the level specified in paragraph (a)(4) of this section for 2 years (i.e., 8 consecutive quarterly samples), twelve 14-day sampling periods can be skipped for that analyte for that monitoring site following each period of sampling, i.e., sampling will occur twice a year.

(D) For the analyte of interest, if every sample at a monitoring site that is monitored at the frequency specified in paragraph (a)(3)(iii)(C) of this section is at or below the level specified in paragraph (a)(4) of this section for 2 years (i.e., 4 consecutive semiannual samples), only one sample per year is required for that analyte for that monitoring site. For yearly sampling, samples shall occur at least 10 months but no more than 14 months apart.

(E) If at any time a sample for a monitoring site that is monitored for the analyte at the frequency specified in paragraph (a)(3)(iii)(A) through (D) of this section returns a result for the analyte that is above the level specified in paragraph (a)(4) of this section, the sampling site must return to the original sampling requirements for the analyte of contiguous 14-day sampling periods with no skip periods for one quarter (six 14-day sampling periods). If every sample collected for the analyte during this quarter is at or below the level specified in paragraph (a)(4) of this section, the owner or operator may revert back to the reduced monitoring schedule applicable for that analyte for that monitoring site prior to the sample reading exceeding the level specified in paragraph (a)(4) of this section. If any sample collected for the analyte during this quarter is above the level specified in paragraph (a)(4) of this section, that monitoring site must return to the original sampling requirements for that analyte of contiguous 14-day sampling periods with no skip periods for a minimum of two years. The burden reduction requirements can be used again for that analyte for that monitoring site once the requirements of paragraph (a)(3)(iii)(A) of this section are met again, i.e., after 52 contiguous 14-day samples with no results above the level specified in paragraph (a)(4) of this section.

(4) To use the alternative sampling frequency outlined in paragraph (a)(3) of this section, an individual monitor must consistently achieve results for the analyte at or below the level specified in paragraphs (a)(4)(i) through (iii) of this section.

(i) For benzene, the results must be consistently at or below 0.9 µg/m 3.

(ii) For 1,3-butadiene, the results must be consistently at or below 0.3 µg/m 3.

(iii) For ethylene dichloride, the results must be consistently at or below 0.4 µg/m 3.

(b) The owner or operator must conduct sampling along the facility property boundary and analyze the samples in accordance with Method 327 of appendix A to this part and paragraphs (b)(1) through (3) of this section.

(1) The owner or operator must monitor the target analyte(s), as specified in paragraphs (b)(1)(i) and (ii) of this section.

(i) If an affected source uses, produces, stores, or emits ethylene oxide, the owner or operator must include ethylene oxide as a target analyte.

(ii) If an affected source uses, produces, stores, or emits vinyl chloride, the owner or operator must include vinyl chloride as a target analyte.

(2) The owner or operator must use a sampling period and sampling frequency as specified in paragraphs (b)(2)(i) and (ii) of this section.

(i) Sampling period. A 24-hour sampling period must be used, unless a shorter sampling period is determined to be necessary under paragraph (e) or (g) of this section. A sampling period is defined as the period during which the canister is deployed at a specific sampling location and actively sampling and does not include the time required to analyze the sample. For the purpose of this subpart, a 24-hour sampling period may be no shorter than 23 hours and no longer than 25 hours.

(ii) Base sampling frequency. Except as provided in paragraph (b)(2)(iii) of this section, the frequency of sample collection must be once every 5 calendar days, such that the beginning of each sampling period begins approximately 96 hours (± 24 hours) from the end of the previous sample.

(iii) Alternative sampling frequency for burden reduction. This alternative is only applicable for the measurement of vinyl chloride from sites with a monitoring perimeter less than or equal to 5,000 meters. When an individual sampling point consistently achieves results at or below 0.3 µg/m 3, the owner or operator may elect to use the applicable minimum sampling frequency specified in paragraphs (b)(2)(iii)(A) through (E) of this section for that sampling site for vinyl chloride. If ethylene oxide is a required analyte, the owner or operator must continue to monitor ethylene oxide at the frequency specified in paragraph (b)(2)(ii) of this section. When calculating Δc for the monitoring period when using this alternative for burden reduction, use zero for the lowest sampling result for each monitoring period where one or more samples was not taken for vinyl chloride.

(A) If every sample at a monitoring site is at or below 0.3 µg/m 3 for 2 years (52 consecutive samples), every other sampling period can be skipped for that sampling site, i.e., sampling will occur approximately once per month.

(B) If every sample at a sampling site that is monitored at the frequency specified in paragraph (b)(2)(iii)(A) of this section is at or below 0.3 µg/m 3 for 2 years (i.e., 26 consecutive “monthly” samples), five 14-day sampling periods can be skipped for that sampling site following each period of sampling, i.e., sampling will occur approximately once per quarter.

(C) If every sample at a sampling site that is monitored at the frequency specified in paragraph (b)(2)(iii)(B) of this section is at or below 0.3 µg/m 3 for 2 years (i.e., 8 consecutive quarterly samples), twelve 14-day sampling periods can be skipped for that sampling site following each period of sampling, i.e., sampling will occur twice a year.

(D) If every sample at a sampling site that is monitored at the frequency specified in paragraph (b)(2)(iii)(C) of this section is at or below 0.3 µg/m 3 for 2 years (i.e., 4 consecutive semiannual samples), only one sample per year is required for that sampling site. For yearly sampling, samples shall occur at least 10 months but no more than 14 months apart.

(E) If at any time a sample for a sampling site that is monitored at the frequency specified in paragraphs (b)(2)(iii)(A) through (E) of this section returns a result that is above 0.3 µg/m 3, the sampling site must return to the original sampling requirements of sampling every 5 calendar days with no skip periods for one quarter (18 5-day sampling periods). If every sample collected during this quarter is at or below 0.3 µg/m 3, the owner or operator may revert back to the reduced monitoring schedule applicable for that sampling site prior to the sample reading exceeding 0.3 µg/m 3. If any sample collected during this quarter is above 0.3 µg/m 3, that sampling site must return to the original sampling requirements of sampling every 5 calendar days with no skip periods for a minimum of two years. The burden reduction requirements can be used again for that sampling site once the requirements of paragraph (b)(2)(ii)(A) of this section are met again, i.e., after 146 consecutive samples with no results above 0.3 µg/m 3.

(3) The owner or operator must determine canister sample locations in accordance with paragraphs (b)(3)(i) through (v) of this section.

(i) The monitoring perimeter must be located on or inside the facility property boundary. If the monitoring perimeter is located away from the facility property boundary, the monitoring perimeter must encompass all potential sources of the target analyte(s) specified in paragraph (b)(1) of this section that are located within the facility's property boundary. If the site contains process units that are disconnected (i.e., one or more process areas are not within the boundary of the main facility), the owner or operator must follow the requirements in paragraph (b)(3)(v) of this section. Canisters are not required to be placed along internal roads, waterways, or other right of ways that may bisect the facility. If a facility is bounded by a waterway on one or more sides, the shoreline is considered the facility property boundary.

(ii) The owner or operator must place 8 canisters around the monitoring perimeter during each sampling period.

(iii) To determine sampling locations, measure the length of the monitoring perimeter.

(A) Locate the point on the monitoring perimeter that is closest to sources of the target analyte(s). If one of the target analytes is ethylene oxide, this point must be the point on the monitoring perimeter that is closest to the sources of ethylene oxide.

(B) If the monitoring perimeter is less than or equal to 5,000 meters, divide the monitoring perimeter into 8 evenly spaced sampling points, with one point located in accordance with the requirements of paragraph (b)(3)(iii)(A) of this section.

(C) If the monitoring perimeter is greater than 5,000 meters, but less than or equal to 10,000 meters, divide the monitoring perimeter into 16 evenly spaced sampling points, with one point located in accordance with the requirements of paragraph (b)(3)(iii)(A) of this section.

(D) If the monitoring perimeter is greater than 10,000 meters, divide the monitoring perimeter into 24 evenly spaced sampling points, with one point located in accordance with the requirements of paragraph (b)(3)(iii)(A) of this section.

(iv) Place canisters on the monitoring perimeter at the sampling points as follows.

(A) If there are only 8 sampling points for the site, monitor each sampling point during each sampling period.

(B) If there are 16 sampling points for the site, number the sampling points consecutively along the monitoring perimeter. During the first sampling period, monitor the odd numbered sampling points. During the second sampling period, monitor the even numbered sampling points. Continue to alternate between the odd numbered and even numbered sampling points in subsequent sampling periods.

(C) If there are 24 sampling points for the site, number the sampling points consecutively along the monitoring perimeter. During the first sampling period, monitor every third sampling point starting with the first sampling point (i.e., points 1, 4, 7, etc.). During the second sampling period, monitor every third sampling point starting with the second sampling point (i.e., points 2, 5, 8, etc.). During the third sampling period, monitor every third sampling point starting with the third sampling point (i.e., points 3, 6, 9, etc.). Continue to alternate between these placements for each subsequent sampling period (i.e., the fourth sampling period will include every third sampling point starting with the first sampling point, the fifth sampling period will include every third sampling point starting with the second sampling point, and so on).

(v) If the site consists of small areas disconnected from the main facility, additional monitors must be placed on these areas in accordance with paragraphs (b)(3)(v)(A) through (C) of this section. The monitoring perimeter for the disconnected area(s) must be located between the property boundary of the area and the process unit(s), such that the monitoring perimeter for the disconnected area encompasses all potential sources of the target analyte(s) specified in paragraph (b)(1) of this section.

(A) If the disconnected area is less than 50 acres, the owner or operator must sample at two locations each sampling period. One location must be placed in the expected prevailing wind direction for the sampling period, downwind of the main source of emissions of the target analyte(s). The other location must be located on the monitoring perimeter at 180 degrees from the first sample location.

(B) If the disconnected area is equal to or greater than 50 acres but less than or equal to 150 acres, the owner or operator must sample at four equally spaced locations. One sampling point must be located on the monitoring perimeter at the point that is closest to sources of the target analyte(s). If one of the target analytes is ethylene oxide, this point must be the point on the monitoring perimeter that is closest to the sources of ethylene oxide.

(C) If the disconnected area is greater than 150 acres, the sampling points for the disconnected area must be determined according to paragraphs (b)(3)(ii) through (iv) of this section.

(4) At least one co-located duplicate sample and at least one field blank must be collected per sampling period.

(5) The owner or operator must follow the procedures in Method 327 of appendix A to this part to determine the detection limit of the target analyte(s) and requirements for quality assurance samples.

(c) The owner or operator must collect and record meteorological data according to the applicable requirements in paragraphs (c)(1) through (3) of this section.

(1) If monitoring is conducted under paragraph (b) of this section, if a near-field source correction is used as provided in paragraph (g)(2) of this section, or if an alternative test method is used that provides time-resolved measurements, the owner or operator must use an on-site meteorological station in accordance with Section 8.3 of Method 325A of appendix A to this part. Collect and record hourly average meteorological data, including temperature, barometric pressure, wind speed and wind direction and calculate daily unit vector wind direction and daily sigma theta.

(2) For cases other than those specified in paragraph (c)(1) of this section, the owner or operator must collect and record sampling period average temperature and barometric pressure using either an on-site meteorological station in accordance with Section 8.3 of Method 325A of appendix A to this part or, alternatively, using data from a National Weather Service (NWS) meteorological station provided the NWS meteorological station is within 40 kilometers (25 miles) of the facility.

(3) If an on-site meteorological station is used, the owner or operator must follow the calibration and standardization procedures for meteorological measurements in EPA-454/B-08-002 (incorporated by reference, see § 63.14).

(d) Within 45 days of completion of each sampling period, the owner or operator must determine whether the results are above or below the action level for each measured compound as follows. If the owner or operator is required to monitor any small disconnected area(s) of the facility under paragraph (b)(3)(v) of this section, the procedure for determining whether the results are above or below the action level for each measured compound must be performed for the disconnected area(s) separately.

(1) The owner or operator must determine the facility impact on the concentration (Δc) of each compound for each sampling period according to either paragraph (d)(1)(i) or (ii) of this section, as applicable.

(i) Except when near-field source correction is used as provided in paragraph (d)(1)(ii) of this section, the owner or operator must determine the highest and lowest sample results for each compound individually from the sample pool and calculate each compound's Δc as the difference in these concentrations. Co-located samples must be averaged together for the purposes of determining the concentration at a particular sampling location, and, if applicable, for determining Δc. The owner or operator must adhere to the following procedures when one or more samples for the sampling period are below the method detection limit for a particular compound:

(A) If the lowest detected value of a compound is below detection, the owner or operator must use zero as the lowest sample result when calculating Δc.

(B) If all sample results are below the method detection limit, the owner or operator must use the highest method detection limit for the sample set as the highest sample result and zero as the lowest sample result when calculating Δc.

(C) In the case of co-located samples, if one sample is above the method detection limit while the other sample is below the method detection limit, the owner or operator must use the method detection limit as the result for the sample that is below the method detection limit for purposes of averaging the results to determine the concentration at a particular sampling location, and, if applicable, for determining Δc.

(ii) When near-field source correction for a compound is used as provided in paragraph (g) of this section, the owner or operator must determine Δc using the calculation protocols outlined in paragraph (d)(1)(i) of this section, except as provided in this paragraph (d)(1)(ii), and the additional requirements in paragraph (g)(2) of this section, as well as any additional requirements outlined in the approved site-specific monitoring plan. The Δc for the compound for the sampling period is equal to the higher of the values in paragraphs (d)(1)(ii)(A) and (B) of this section.

(A) The highest corrected sample result for the compound from a sampling location where near-field source correction for the compound is used during the sampling period.

(B) The difference in concentration between the highest sample result that was not corrected for a near-field source for the compound during the sampling period and the lowest sample result for the compound for the sampling period.

(2) The owner or operator must calculate the annual average Δc for each monitored compound as follows:

(i) For sampling conducted under paragraph (a) of this section, the annual average Δc for each compound is based on the average of the Δc values for the 26 most recent 14-day sampling periods. The owner or operator must update this annual average value after receiving the results of each subsequent 14-day sampling period.

(ii) For sampling conducted under paragraph (b) of this section, the annual average Δc for each compound is based on the average of the Δc values for the 73 most recent sampling periods. The owner or operator must update this annual average value after receiving the results of each subsequent sampling period.

(3) The action level for each compound is listed in paragraphs (d)(3)(i) through (vi) of this section. If the annual average Δc value for a compound is greater than the listed action level for the compound, the concentration is above the action level, and the owner or operator must conduct a root cause analysis and corrective action in accordance with paragraph (e) of this section.

(i) The action level for benzene is 9 micrograms per cubic meter (µg/m 3) on an annual average basis.

(ii) The action level for 1,3-butadiene is 3 µg/m 3 on an annual average basis.

(iii) The action level for chloroprene is 0.8 µg/m 3 on an annual average basis.

(iv) The action level for ethylene oxide is 0.2 µg/m 3 on an annual average basis.

(v) The action level for vinyl chloride is 3 µg/m 3 on an annual average basis.

(vi) The action level for ethylene dichloride is 4 µg/m 3 on an annual average basis.

(e) Once any action level in paragraph (d)(3) of this section has been exceeded, the owner or operator must take the following actions to bring the annual average Δc back below the action level(s).

(1) Within 5 days of updating the annual average value as required in paragraph (d)(2) of this section and determining that any action level in paragraph (d)(3) of this section has been exceeded (i.e., in no case longer than 50 days after completion of the sampling period), the owner or operator must initiate a root cause analysis to determine appropriate corrective action. A root cause analysis is an assessment conducted through a process of investigation to determine the primary underlying cause and all other contributing causes to an exceedance of an action level(s) set forth in paragraph (d)(3) of this section.

(i) The initial root cause analysis may include, but is not limited to:

(A) Leak inspection using Method 21 of appendix A-7 to 40 CFR part 60, optical gas imaging, or handheld monitors.

(B) Visual inspection to determine the cause of the high emissions.

(C) Operator knowledge of process changes (e.g., a malfunction or release event).

(ii) If the initial root cause cannot be identified using the type of techniques described in paragraph (e)(1)(i) of this section, the owner or operator must employ more frequent sampling and analysis to determine the root cause of the exceedance.

(A) The owner or operator may first employ additional monitoring points and shorter sampling periods for Methods 325A and 325B of appendix A to this part for benzene, 1,3-butadiene, chloroprene, or ethylene dichloride or more frequent sampling with Method 327 of appendix A to this part for ethylene oxide or vinyl chloride to determine the root cause of the exceedance.

(B) If the owner or operator has not determined the root cause of the exceedance within 30 days of determining that the action level has been exceeded, the owner or operator must employ the appropriate real-time sampling techniques (e.g., mobile gas chromatographs, optical spectroscopy instruments, sensors) to locate the cause of the exceedance. If the root cause is not identified after 48 hours, either the real-time monitor must be relocated or an additional real-time monitor must be added. Relocation or addition of extra real-time monitors must continue after each 48-hour period of nonidentification until the owner or operator can identify the root cause of the exceedance.

(2) If the underlying primary and other contributing causes of the exceedance are deemed to be under the control of the owner or operator, the owner or operator must take appropriate corrective action as expeditiously as possible to bring annual average fenceline concentrations back below the action level(s) set forth in paragraph (d)(3) of this section. At a minimum, the corrective actions taken must address the underlying primary and other contributing cause(s) determined in the root cause analysis to prevent future exceedances from the same underlying cause(s).

(3) The root cause analysis must be completed and initial corrective actions taken no later than 45 days after determining there is an exceedance of an action level.

(4) Until the annual average Δc is below the action level again, following completion of the initial corrective action, the owner or operator must conduct a new root cause analysis according to this paragraph (e), and if required, submit a corrective action plan under paragraph (f) of this section following any sampling period for which the sampling start time begins after the completion of the initial corrective actions and for which the Δc for the sampling period is greater than the level specified in paragraphs (e)(4)(i) through (vi) of this section for the compound(s) that initially exceeded the action level.

(i) For benzene, a sampling period Δc of 9 µg/m 3.

(ii) For 1,3-butadiene, a sampling period Δc of 3 µg/m 3.

(iii) For chloroprene, a sampling period Δc of 0.8 µg/m 3.

(iv) For ethylene dichloride, a sampling period Δc of 4 µg/m 3.

(v) For ethylene oxide, a sampling period Δc of 0.2 µg/m 3.

(vi) For vinyl chloride, a sampling period Δc of 3 µg/m 3.

(f) An owner or operator must develop a corrective action plan if the conditions in paragraphs (f)(1), (2), or (3) of this section are met. The corrective action plan must describe the corrective action(s) completed to date, additional measures that the owner or operator proposes to employ to reduce annual average fenceline concentrations below the action level(s) set forth in paragraph (d)(3) of this section, and a schedule for completion of these measures. The corrective action plan does not need to be approved by the Administrator. However, if upon review, the Administrator disagrees with the additional measures outlined in the plan, the owner or operator must revise and resubmit the plan within 7 calendar days of receiving comments from the Administrator.

(1) If the compound that exceeded the action level was benzene, 1,3-butadiene, chloroprene, or ethylene dichloride, the owner or operator must develop a corrective action plan if, upon completion of the root cause analysis and initial corrective actions required in paragraph (e) of this section, the Δc value for the next sampling period, for which the sampling start time begins after the completion of the initial corrective actions, is greater than the level specified in paragraphs (f)(1)(i) through (iv) of this section for the compound(s) that initially exceeded the action level. The corrective action plan must include the implementation of real-time sampling techniques to locate the primary and other contributing causes of the exceedance. The owner or operator must submit the corrective action plan to the Administrator within 60 days after receiving the analytical results indicating that the Δc value for the sampling period following the completion of the initial corrective action is greater than the level specified in paragraphs (f)(1)(i) through (iv) of this section.

(i) For benzene, a sampling period Δc of 9 µg/m 3.

(ii) For 1,3-butadiene, a sampling period Δc of 3 µg/m 3.

(iii) For chloroprene, a sampling period Δc of 0.8 µg/m 3.

(iv) For ethylene dichloride, a sampling period Δc of 4 µg/m 3.

(2) If the compound that exceeded the action level was ethylene oxide or vinyl chloride, the owner or operator must develop a corrective action plan if, upon completion of the root cause analysis and initial corrective actions required in paragraph (e) of this section, the Δc value for any of the next three sampling periods, for which the sampling start time begins after the completion of the initial corrective actions, is greater than the level specified in paragraphs (f)(2)(i) and (ii) of this section for the compound(s) that initially exceeded the action level. The corrective action plan must include the implementation of real-time sampling techniques to locate the primary and other contributing causes of the exceedance. The owner or operator must submit the corrective action plan to the Administrator within 60 days after receiving the analytical results indicating that the Δc value for the sampling period following the completion of the initial corrective action is greater than the level specified in paragraphs (f)(2)(i) and (ii) of this section.

(i) For ethylene oxide, a sampling period Δc of 0.2 µg/m 3.

(ii) For vinyl chloride, a sampling period Δc of 3 µg/m 3.

(3) The owner or operator must develop a corrective action plan if complete implementation of all corrective measures identified in the root cause analysis required by paragraph (e) of this section will require more than 45 days. The owner or operator must submit the corrective action plan to the Administrator no later than 60 days following the completion of the root cause analysis required in paragraph (e) of this section.

(g) An owner or operator may request approval from the Administrator for a site-specific monitoring plan to account for offsite upwind sources according to the requirements in paragraphs (g)(1) through (4) of this section.

(1) The owner or operator must prepare and submit a site-specific monitoring plan and receive approval of the site-specific monitoring plan prior to using the near-field source alternative calculation for determining Δc provided in paragraph (g)(2) of this section. The site-specific monitoring plan must include, at a minimum, the elements specified in paragraphs (g)(1)(i) through (vi) of this section. The procedures in Section 12 of Method 325A of appendix A to this part are not required, but may be used, if applicable, when determining near-field source contributions.

(i) Identification of the near-field source or sources.

(ii) Location of the additional monitoring stations that will be used to determine the near-field source concentration contribution. The owner or operator must use additional monitoring stations to determine the near-field source contribution.

(iii) Identification of the fenceline monitoring locations impacted by the near-field source. If more than one near-field source is present, identify the near-field source or sources that are expected to contribute to the concentration at that monitoring location.

(iv) A description of (including sample calculations illustrating) the planned data reduction; the treatment of invalid data, data below detection limits, and data collected during calm wind periods; and calculations to determine the near-field source concentration contribution for each monitoring location.

(v) A detailed description of the measurement technique, measurement location(s), the standard operating procedures, measurement frequency, recording frequency, measurement detection limit, and data quality indicators to ensure accuracy, precision, and validity of the data.

(vi) A detailed description of how data will be handled during periods of calm wind conditions (i.e., less than 2 miles per hour).

(2) When an approved site-specific monitoring plan is used, the owner or operator must determine Δc for comparison with the action level according to paragraph (d) of this section. When determining the highest and lowest sample results for use in the Δc calculation, the concentration for any monitor that has been corrected using an approved site-specific monitoring plan will be corrected according to the procedures specified in paragraphs (g)(2)(i) and (ii) of this section.

(i) For each monitoring location corrected using the site-specific monitoring plan, the corrected fenceline concentration at that monitoring station will be equal to the fenceline concentration measured with Methods 325A and 325B or Method 327 of appendix A to this part minus the near-field source contributing concentration at the measurement location determined using the additional measurements and calculation procedures included in the site-specific monitoring plan.

(ii) If the fenceline concentration at the monitoring station is below the method detection limit for Methods 325A and 325B or Method 327 of appendix A to this part, no near-field source contribution can be subtracted from that monitoring station for that sampling period.

(3) The site-specific monitoring plan must be submitted and approved as described in paragraphs (g)(3)(i) through (iv) of this section.

(i) The site-specific monitoring plan must be submitted to the Administrator for approval.

(ii) The site-specific monitoring plan must also be submitted to the following address: U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards, Sector Policies and Programs Division, U.S. EPA Mailroom (E143-01), Attention: Hazardous Organic Chemical Manufacturing Sector Lead, 109 T.W. Alexander Drive, P.O. Box 12055, Research Triangle Park, NC 27711. Electronic copies in lieu of hard copies may also be submitted to [email protected].

(iii) The Administrator will approve or disapprove the plan in 90 days. The plan is considered approved if the Administrator either approves the plan in writing or fails to disapprove the plan in writing. The 90-day period begins when the Administrator receives the plan.

(iv) If the Administrator finds any deficiencies in the site-specific monitoring plan and disapproves the plan in writing, the owner or operator may revise and resubmit the site-specific monitoring plan following the requirements in paragraphs (g)(3)(i) and (ii) of this section. The 90-day period starts over with the resubmission of the revised monitoring plan.

(4) The approval by the Administrator of a site-specific monitoring plan will be based on the completeness, accuracy and reasonableness of the request for a site-specific monitoring plan. Factors that the Administrator will consider in reviewing the request for a site-specific monitoring plan include, but are not limited to, those described in paragraphs (g)(4)(i) through (v) of this section.

(i) The identification of the near-field source or sources and evidence of how the sources impact the fenceline concentrations.

(ii) The location(s) selected for additional monitoring to determine the near-field source concentration contribution.

(iii) The identification of the fenceline monitoring locations impacted by the near-field source or sources.

(iv) The appropriateness of the planned data reduction and calculations to determine the near-field source concentration contribution for each monitoring location, including the handling of invalid data, data below the detection limit, and data during calm periods.

(v) The adequacy of the description of and rationale for the measurement technique, measurement location(s), the standard operation procedure, measurement frequency, recording frequency, measurement detection limit, and data quality indicators to ensure accuracy, precision, and validity of the data.

(h) The owner or operator must comply with the applicable recordkeeping and reporting requirements in §§ 63.181 and 63.182.

(i) As outlined in § 63.7(f), the owner or operator may submit a request for an alternative test method. At a minimum, the request must follow the requirements outlined in paragraphs (i)(1) through (7) of this section.

(1) The alternative method may be used in lieu of all or a partial number of passive samplers required in Method 325A of appendix A to this part or the canister sampling locations required under paragraph (b) of this section.

(2) The alternative method must be validated according to Method 301 in appendix A to this part or contain performance-based procedures and indicators to ensure self-validation.

(3) The method detection limit must nominally be at least one-third of the action level for the compound(s) that will be monitored with the alternative method. The alternate test method must describe the procedures used to provide field verification of the detection limit.

(4) If the alternative test method will be used to replace some or all passive samplers required under paragraph (a) of this section, the spatial coverage must be equal to or better than the spatial coverage provided in Method 325A of appendix A to this part. If the alternative test method will be used to replace some or all canisters required under paragraph (b) of this section, the spatial coverage must be equal to or better than the spatial coverage provided under paragraph (b) of this section.

(i) For path average concentration open-path instruments, the physical path length of the measurement must be no more than a passive sample footprint (the spacing that would be provided by the sorbent traps when following Method 325A of appendix A to this part) or canister sample footprint, as applicable. For example, if Method 325A requires spacing monitors A and B 610 meters (2,000 feet) apart, then the physical path length limit for the measurement at that portion of the fenceline must be no more than 610 meters (2,000 feet).

(ii) For range resolved open-path instrument or approach, the instrument or approach must be able to resolve an average concentration over each passive sampler footprint or canister sample footprint within the path length of the instrument.

(iii) The extra samplers required in Sections 8.2.1.3 of Method 325A of appendix A to this part may be omitted when they fall within the path length of an open-path instrument.

(5) At a minimum, non-integrating alternative test methods must provide a minimum of one cycle of operation (sampling, analyzing, and data recording) for each successive 15-minute period.

(6) For alternative test methods capable of real time measurements (less than a 5 minute sampling and analysis cycle), the alternative test method may allow for elimination of data points corresponding to outside emission sources for purpose of calculation of the high point for the two week average. The alternative test method approach must have wind speed, direction and stability class of the same time resolution and within the footprint of the instrument.

(7) For purposes of averaging data points to determine the Δc for the individual sampling period, all results measured under the method detection limit must use the method detection limit. For purposes of averaging data points for the individual sampling period low sample result, all results measured under the method detection limit must use zero.

[89 FR 43228, May 16, 2024]