---
kind: "range"
citation: "40 C.F.R. §§ 63.493–63.500"
title: "40"
from: "63.493"
to: "63.500"
count: 8
url: "https://uscodex.org/cfr/40/63.493..63.500"
---

# §63.493. Back-end process provisions.


Owners and operators of new and existing affected sources shall comply with the requirements in [§§ 63.494 through 63.500](/cfr/40/63.494..63.500.md). Owners and operators of affected sources whose only elastomer products are latex products, liquid rubber products, or products produced in a gas-phased reaction process, are not subject to the provisions of [§§ 63.494 through 63.500](/cfr/40/63.494..63.500.md). If latex or liquid rubber products are produced in an affected source that also produces another elastomer product, the provisions of [§§ 63.494 through 63.500](/cfr/40/63.494..63.500.md) do not apply to the back-end operations dedicated to the production of one or more latex products, or to the back-end operations during the production of a latex product. Table 8 to this subpart contains a summary of compliance alternative requirements for the emission limits in [§ 63.494(a)(1)-(3)](/cfr/40/63.494.md?p=a-1..a-3) and associated requirements.


# §63.494. Back-end process provisions—residual organic HAP and emission limitations.

- (a) The monthly weighted average residual organic HAP content of all grades of styrene butadiene rubber produced by the emulsion process, polybutadiene rubber and styrene butadiene rubber produced by the solution process, and ethylene-propylene rubber produced by the solution process that is processed, shall be measured after the stripping operation (or the reactor(s), if the plant has no stripper(s)), as specified in [§ 63.495(d)](/cfr/40/63.495.md?p=d), and shall not exceed the limits provided in [paragraphs (a)(1) through (3)](#a-1..a-3) of this section, as applicable. Owners or operators of these affected sources shall comply with the requirements of [paragraphs (a)(1) through (3)](#a-1..a-3) of this section using either stripping technology, or control or recovery devices. The organic HAP emissions from all back-end process operations at affected sources producing butyl rubber, epichlorohydrin elastomer, neoprene, and nitrile butadiene rubber shall not exceed the limits determined in accordance with [paragraph (a)(4)](#a-4) of this section, as applicable.
  - (1) **For styrene butadiene rubber produced by the emulsion process—**
    - (i) A monthly weighted average of 0.40 kg styrene per megagram (Mg) latex for existing affected sources; and
    - (ii) A monthly weighted average of 0.23 kg styrene per Mg latex for new sources;
  - (2) **For polybutadiene rubber and styrene butadiene rubber produced by the solution process—**
    - (i) A monthly weighted average of 10 kg total organic HAP per Mg crumb rubber (dry weight) for existing affected sources; and
    - (ii) **A monthly weighted average of 6 kg total organic HAP per Mg crumb rubber (dry weight) for new sources.**
  - (3) **For ethylene-propylene rubber produced by the solution process—**
    - (i) A monthly weighted average of 8 kg total organic HAP per Mg crumb rubber (dry weight) for existing affected sources; and
    - (ii) **A monthly weighted average of 5 kg total organic HAP per Mg crumb rubber (dry weight) for new sources.**
  - (4) In addition to the requirements specified in [paragraph (a)(7)](#a-7) of this section, the organic HAP emissions from back-end processes at affected sources producing butyl rubber, epichlorohydrin elastomer, neoprene, and nitrile butadiene rubber shall not exceed the limits determined in accordance with [paragraphs (a)(4)(i) through (iv)](#a-4-i..a-4-iv) of this section for any consecutive 12-month period. The specific limitation for each elastomer type shall be determined based on the calculation or the emissions level provided in [paragraphs (a)(4)(i) through (iv)](#a-4-i..a-4-iv) of this section divided by the base year elastomer product that leaves the stripping operation (or the reactor(s), if the plant has no stripper(s)). The limitation shall be calculated and submitted in accordance with [§ 63.499(f)(1)](/cfr/40/63.499.md?p=f-1).
    - (i) For butyl rubber, the organic HAP emission limitation shall be calculated using the following equation:
    - (ii) For epichlorohydrin elastomer, the organic HAP emission limitation, in units of Mg organic HAP emissions per Mg of epichlorohydrin elastomer produced, shall be calculated by dividing 51 Mg/yr by the mass of epichlorohydrin elastomer produced in 2009, in Mg.
    - (iii) For neoprene, the organic HAP emission limitation, in units of Mg organic HAP emissions per Mg of neoprene produced, shall be calculated by dividing 30 Mg/yr by the mass of neoprene produced in 2007, in Mg.
    - (iv) For nitrile butadiene rubber, the organic HAP emission limitation, in units of Mg organic HAP emissions per Mg of nitrile butadiene rubber produced, shall be calculated by dividing 2.4 Mg/yr by the mass of nitrile butadiene rubber produced in 2009, in Mg.
  - (5) For EPPU that produce both an elastomer product with a residual organic HAP limitation listed in [paragraphs (a)(1) through (3)](#a-1..a-3) of this section, and a product listed in [paragraphs (a)(5)(i) through (iv)](#a-5-i..a-5-iv) of this section, only the residual HAP content of the elastomer product with a residual organic HAP limitation shall be used in determining the monthly average residual organic HAP content.
    - (i) Resins;
    - (ii) Liquid rubber products;
    - (iii) Latexes from which crumb rubber is not coagulated; or
    - (iii) **Elastomer products listed in paragraph (a)(4) of this section.**
  - (6) There are no back-end process operation residual organic HAP or emission limitations for Hypalon TM and polysulfide rubber production. There are also no back-end process operation residual organic HAP limitations for latex products, liquid rubber products, products produced in a gas-phased reaction process, styrene butadiene rubber produced by any process other than a solution or emulsion process, polybutadiene rubber produced by any process other than a solution process, or ethylene-propylene rubber produced by any process other than a solution process.
  - (7) For each affected source as described in [§ 63.480](/cfr/40/63.480.md), beginning no later than the compliance dates specified in [§ 63.481(o)](/cfr/40/63.481.md?p=o), if the back-end process vent contains chloroprene such that it is considered to be in chloroprene service, as defined in [§ 63.482](/cfr/40/63.482.md), then the owner or operator must comply with the requirements of [paragraphs (a)(7)(i) through (iii)](#a-7-i..a-7-iii) of this section in addition to all other applicable requirements specified in [§ 63.483](/cfr/40/63.483.md) and elsewhere in this section.
    - (i) Reduce emissions of chloroprene by venting emissions through a closed vent system to a non-flare control device that reduces chloroprene by greater than or equal to 98 percent by weight, or to a concentration less than 1 ppmv for each process vent or to less than 5 pounds per year for all combined process vents within the process. If a combustion device is used, the chloroprene concentration of 1 ppmv must be corrected to 3 percent oxygen.
    - (ii) To demonstrate compliance with the emission limits specified in [paragraph (a)(7)(i)](#a-7-i) of this section for back-end process vents in chloroprene service, owners and operators must meet the requirements specified in [§ 63.510](/cfr/40/63.510.md).
    - (iii) An owner or operator may designate a back-end process vent in chloroprene service as a maintenance vent if the vent is only used as a result of startup, shutdown, maintenance, or inspection of equipment where equipment is emptied, depressurized, degassed, or placed into service; however, owners and operators may not release more than 1.0 tons of chloroprene from all maintenance vents combined (i.e., including maintenance vents subject to this [paragraph (a)(7)(iii)](#a-7-iii), [§ 63.485(z)](/cfr/40/63.485.md?p=z), or [§ 63.487(i)(4)](/cfr/40/63.487.md?p=i-4)) per any consecutive 12-month period. The owner or operator must keep monthly records of the quantity in tons of chloroprene released from each maintenance vent and include a description of the method used to estimate this quantity.
- (b) If an owner or operator complies with the residual organic HAP limitations in [paragraph (a)(1) through (3)](#a-1..a-3) of this section using stripping technology, compliance shall be demonstrated in accordance with [§ 63.495](/cfr/40/63.495.md). The owner or operator shall also comply with the recordkeeping provisions in [§ 63.498](/cfr/40/63.498.md), and the reporting provisions in [§ 63.499](/cfr/40/63.499.md).
- (c) If an owner or operator complies with the residual organic HAP limitations in [paragraph (a)(1) through (3)](#a-1..a-3) of this section using control or recovery devices, compliance shall be demonstrated using the procedures in [§ 63.496](/cfr/40/63.496.md). The owner or operator shall also comply with the monitoring provisions in [§ 63.497](/cfr/40/63.497.md), the recordkeeping provisions in [§ 63.498](/cfr/40/63.498.md), and the reporting provisions in [§ 63.499](/cfr/40/63.499.md).
- (d) Except as specified in [paragraph (e)](#e) of this section, if the owner or operator complies with the residual organic HAP limitations in [paragraph (a)(1) through (3)](#a-1..a-3) of this section using a flare, the owner or operator of an affected source shall comply with the requirements in [§ 63.504(c)](/cfr/40/63.504.md?p=c).
- (e) For each affected source as described in [§ 63.480](/cfr/40/63.480.md), beginning no later than the compliance dates specified in [§ 63.481(n)](/cfr/40/63.481.md?p=n), [paragraph (d)](#d) of this section no longer applies and instead if the owner or operator complies with the residual organic HAP limitations in [paragraph (a)(1) through (3)](#a-1..a-3) of this section using a flare, the owner or operator of the affected source must comply with [§ 63.508](/cfr/40/63.508.md) for the flare.

# §63.495. Back-end process provisions—procedures to determine compliance with residual organic HAP limitations using stripping technology and organic HAP emissions limitations.

- (a) If an owner or operator complies with the residual organic HAP limitations in [§ 63.494(a)(1) through (3)](/cfr/40/63.494.md?p=a-1..a-3) using stripping technology, compliance shall be demonstrated using the periodic sampling procedures in [paragraph (b)](#b) of this section, or using the stripper parameter monitoring procedures in [paragraph (c)](#c) of this section. The owner or operator shall determine the monthly weighted average residual organic HAP content for each month in which any portion of the back-end of an elastomer production process is in operation. A single monthly weighted average shall be determined for all back-end process operations at the affected source.
- (b) If the owner or operator is demonstrating compliance using periodic sampling, this demonstration shall be in accordance with [paragraphs (b)(1) through (b)(5)](#b-1..b-5) of this section,
  - (1) The location of the sampling shall be in accordance with [paragraph (d)](#d) of this section.
  - (2) The frequency of the sampling shall be in accordance with paragraphs [(b)(2)(i)](#b-2-i) or [(b)(2)(ii)](#b-2-ii) of this section.
    - (i) If a stripper operated in batch mode is used, at least one representative sample is to be taken from every batch of elastomer produced, at the location specified in [paragraph (d)](#d) of this section, and identified by elastomer type and by the date and time the batch is completed.
    - (ii) If a stripper operated in continuous mode is used, at least one representative sample is to be taken each operating day. The sample is to be taken at the location specified in [paragraph (d)](#d) of this section, and identified by elastomer type and by the date and time the sample was taken.
  - (3) The residual organic HAP content in each sample is to be determined using the Methods specified in [paragraph (e)](#e) of this section.
  - (4) The quantity of material (weight of latex or dry crumb rubber) represented by each sample shall be recorded. Acceptable methods of determining this quantity are production records, measurement of stream characteristics, and engineering calculations.
  - (5) The monthly weighted average shall be determined using the equation in [paragraph (f)](#f) of this section. All representative samples taken and analyzed during the month shall be used in the determination of the monthly weighted average.
- (c) If the owner or operator is demonstrating compliance using stripper parameter monitoring, this demonstration shall be in accordance with [paragraphs (c)(1) through (c)(4)](#c-1..c-4) of this section.
  - (1) The owner or operator shall establish stripper operating parameter levels for each grade in accordance with [§ 63.505(e)](/cfr/40/63.505.md?p=e).
  - (2) The owner or operator shall monitor the stripper operating parameters at all times the stripper is in operation. Readings of each parameter shall be made at intervals no greater than 15 minutes.
  - (3) The residual organic HAP content for each grade shall be determined in accordance with either paragraph [(c)(3)(i)](#c-3-i) or [(c)(3)(ii)](#c-3-ii) of this section.
    - (i) If during the processing of a grade in the stripper, all hourly average parameter values are in accordance with operating parameter levels established in [paragraph (c)(1)](#c-1) of this section, the owner or operator shall use the residual organic HAP content determined in accordance with [§ 63.505(e)(1)](/cfr/40/63.505.md?p=e-1).
    - (ii) If during the processing of a grade in the stripper, the hourly average of any stripper monitoring parameter is not in accordance with an established operating parameter level, the residual organic HAP content shall be determined using the procedures in paragraphs [(b)(1)](#b-1) and [(b)(3)](#b-3) of this section.
  - (4) The monthly weighted average shall be determined using the equation in [paragraph (f)](#f) of this section.
- (d) The location of the sampling shall be in accordance with paragraph [(d)(1)](#d-1) or [(d)(2)](#d-2) of this section.
  - (1) For styrene butadiene rubber produced by the emulsion process, the sample shall be a sample of the latex taken at the location specified in either paragraph [(d)(1)(i)](#d-1-i), [(d)(1)(ii)](#d-1-ii), or [(d)(1)(iii)](#d-1-iii) of this section.
    - (i) When the latex is not blended with other materials or latexes, the sample shall be taken at a location meeting all of the following criteria:
      - (A) After the stripping operation,
      - (B) Prior to entering the coagulation operations, and
      - (C) **Before the addition of carbon black or oil extenders.**
    - (ii) When two or more latexes subject to this subpart are blended, samples may be taken in accordance with either [paragraph (d)(1)(ii)](#d-1-ii) (A) or (B) of this section, at a location meeting the requirements of [paragraphs (d)(1)(i)](#d-1-i) (A) through (C) of this section.
      - (A) Individual samples may be taken of each latex prior to blending, or
      - (B) A sample of the blended latex may be taken.
    - (iii) When a latex subject to this subpart is blended with a latex or material not subject to this subpart, a sample shall be taken of the latex prior to blending at a location meeting the requirements of [paragraphs (d)(1)(i)](#d-1-i) (A) through (C) of this section.
  - (2) For styrene butadiene rubber produced by the solution process, polybutadiene rubber produced by the solution process, and ethylene-propylene rubber produced by the solution process, the sample shall be a sample of crumb rubber taken as soon as safe and feasible after the stripping operation, but no later than the entry point for the first unit operation following the stripper (e.g., the dewatering screen).
- (e) The residual organic HAP content in each sample is to be determined using the methods specified in [paragraphs (e)(1) through (e)(5)](#e-1..e-5) of this section, as applicable.
  - (1) For styrene butadiene rubber produced by the emulsion process, either Method 312a, 312b, or 312c of [40 CFR part 63](/cfr/40/part63.md), appendix A, shall be used.
  - (2) For styrene butadiene rubber produced by the solution process, either Method 313a or 313b of [40 CFR part 63](/cfr/40/part63.md), appendix A, shall be used.
  - (3) For polybutadiene rubber produced by the solution process, either Method 313a or 313b of [40 CFR part 63](/cfr/40/part63.md), appendix A, shall be used.
  - (4) For ethylene-propylene rubber produced by the solution process, either Method 310a, 310b, or 310c of [40 CFR part 63](/cfr/40/part63.md), appendix A, shall be used.
  - (5) Alternatively, any other method that has been validated according to the applicable procedures in Method 301 of [40 CFR part 63](/cfr/40/part63.md), appendix A, may be used.
- (f) The monthly weighted average residual organic HAP content shall be calculated using Equation 26.
- (g) Compliance with the organic HAP emission limitations determined in accordance with [§ 63.494(a)(4)](/cfr/40/63.494.md?p=a-4) shall be demonstrated in accordance with [paragraphs (g)(1) through (5)](#g-1..g-5) of this section.
  - (1) Calculate your organic HAP emission limitation in accordance with [§ 63.494(a)(4)(i) through (iv)](/cfr/40/63.494.md?p=a-4-i..a-4-iv), as applicable, record it, and submit it in accordance with [§ 63.499(f)(1)](/cfr/40/63.499.md?p=f-1).
  - (2) Each month, calculate and record the organic HAP emissions from all back-end process operations using engineering assessment. Engineering assessment includes, but is not limited to, the following:
    - (i) **Previous test results, provided the test was representative of current operating practices.**
    - (ii) Bench-scale or pilot-scale test data obtained under conditions representative of current process operating conditions.
    - (iii) Design analysis based on accepted chemical engineering principles, measurable process parameters, or physical or chemical laws or properties. Examples of analytical methods include, but are not limited to:
      - (A) Use of material balances;
      - (B) Estimation of flow rate based on physical equipment design, such as pump or blower capacities;
      - (C) Estimation of organic HAP concentrations based on saturation conditions; and
      - (D) **Estimation of organic HAP concentrations based on grab samples of the liquid or vapor.**
  - (3) **Each month, record the mass of elastomer product produced.**
  - (4) Each month, calculate and record the sums of the organic HAP emissions and the mass of elastomer produced for the previous calendar 12-month period.
  - (5) Each month, divide the total mass of organic HAP emitted for the previous calendar 12-month period by the total mass of elastomer produced during this 12-month period. This value must be recorded in accordance with [§ 63.498(e)](/cfr/40/63.498.md?p=e) and reported in accordance with [§ 63.499(f)(2)](/cfr/40/63.499.md?p=f-2).

# §63.496. Back-end process provisions—procedures to determine compliance with residual organic HAP limitations using control or recovery devices.

- (a) If an owner or operator complies with the residual organic HAP limitations in [§ 63.494(a)(1) through (3)](/cfr/40/63.494.md?p=a-1..a-3) using control or recovery devices, compliance shall be demonstrated using the procedures in paragraphs [(b)](#b) and [(c)](#c) of this section. Previous test results conducted in accordance with [paragraphs (b)(1) through (6)](#b-1..b-6) of this section may be used to determine compliance in accordance with [paragraph (c)](#c) of this section.
- (b) Compliance shall be demonstrated using the provisions in [paragraphs (b)(1) through (b)(8)](#b-1..b-8) of this section, as applicable.
  - (1) A test shall be conducted, the duration of which shall be in accordance with either paragraph [(b)(1)(i)](#b-1-i) or [(b)(1)(ii)](#b-1-ii) of this section, as appropriate.
    - (i) If the back-end process operations are continuous, the test shall consist of three separate one hour runs.
    - (ii) If the back-end process operations are batch, the test shall consist of three separate one-hour runs, unless the duration of the batch cycle is less than one-hour, in which case the run length shall equal the complete duration of the back-end process batch cycle.
  - (2) The test shall be conducted when the grade of elastomer product with the highest residual organic HAP content leaving the stripper is processed in the back-end operations.
  - (3) The uncontrolled residual organic HAP content in the latex or dry crumb rubber shall be determined in accordance with § [63.495(b)(1)](/cfr/40/63.495.md?p=b-1) and [(b)(3)](/cfr/40/63.495.md?p=b-3). A separate sample shall be taken and analyzed for each test run. The sample shall be representative of the material being processed in the back-end operation during the test, and does not need to be taken during the test.
  - (4) The quantity of material (weight of latex or dry crumb rubber) processed during the test run shall be recorded. Acceptable methods of determining this quantity are production records, measurement of stream characteristics, and engineering calculations.
  - (5) The inlet and outlet emissions from the control or recovery device shall be determined using the procedures in [paragraphs (b)(5)(i) through (b)(5)(v)](#b-5-i..b-5-v) of this section, with the exceptions noted in paragraphs [(b)(6)](#b-6) and [(b)(7)](#b-7) of this section. The inlet and outlet emissions shall be determined when the material for which the uncontrolled residual organic HAP content is determined in accordance with [paragraph (b)(3)](#b-3) of this section, is being processed in the equipment controlled by the control or recovery device.
    - (i) Method 1 or 1A of [40 CFR part 60](/cfr/40/part60.md), appendix A, as appropriate, shall be used for selection of the sampling sites. Sampling sites for inlet emissions shall be located as specified in paragraphs [(b)(5)(i)(A)](#b-5-i-A) or [(b)(5)(i)(B)](#b-5-i-B) of this section. Sampling sites for outlet emissions shall be located at the outlet of the control or recovery device.
      - (A) The inlet sampling site shall be located at the exit of the back-end process unit operation before any opportunity for emission to the atmosphere [with the exception of equipment in compliance with the requirements in [§§ 63.502(a) through 63.502(m)](/cfr/40/63.502.md?p=a..m)], and before any control or recovery device.
      - (B) If back-end process vent streams are combined prior to being routed to control or recovery devices, the inlet sampling site may be for the combined stream, as long as there is no opportunity for emission to the atmosphere [with the exception of equipment in compliance with the requirements in [§§ 63.502(a) through 63.502(m)](/cfr/40/63.502.md?p=a..m)] from any of the streams prior to being combined.
    - (ii) The gas volumetric flow rate shall be determined using Method 2, 2A, 2C, or 2D of [40 CFR part 60](/cfr/40/part60.md), appendix A, as appropriate.
    - (iii) To determine the inlet and outlet total organic HAP concentrations, the owner or operator must use Method 18 or Method 25A of appendices A-6 and A-7 to [40 CFR part 60](/cfr/40/part60.md), respectively. ASTM D6420-18 (incorporated by reference, see [§ 63.14](/cfr/40/63.14.md)) may also be used in lieu of Method 18, if the target compounds are all known and are all listed in [Section 1.1](/cfr/40/1.1.md) of ASTM D6420-18 as measurable; ASTM D6420-18 must not be used for methane and ethane; and ASTM D6420-18 may not be used as a total VOC method. Alternatively, any other method or data that has been validated according to the applicable procedures in Method 301 of appendix A to this part may be used. The minimum sampling time for each run must be in accordance with [paragraph (b)(1)](#b-1) of this section, during which either an integrated sample or grab samples shall be taken. If grab sampling is used, then the samples must be taken at approximately equal intervals during the run, with the time between samples no greater than 15 minutes.
    - (iv) The mass rate of total organic HAP shall be computed using Equations 27 and 28.
    - (v) Inlet and outlet organic HAP emissions for the run shall be calculated by multiplying the mass rate total inlet and outlet emissions determined in accordance with [paragraph (b)(5)(iv)](#b-5-iv) of this section by the duration of the run (in hours).
  - (6) If a back-end process vent stream is introduced with the combustion air, or as a secondary fuel into a boiler or process heater with a design capacity less than 44 megawatts, the inlet and outlet emissions shall be determined in accordance with [paragraphs (b)(6)(i) through (b)(6)(iv)](#b-6-i..b-6-iv) of this section.
    - (i) The inlet organic HAP emissions for the back-end process unit operation shall be determined in accordance with [paragraph (b)(5)](#b-5) of this section.
    - (ii) The owner or operator shall also measure total organic HAP (or TOC, minus methane and ethane) emissions in all process vent streams and primary and secondary fuels introduced into the boiler or process heater, using the procedures in [paragraph (b)(5)](#b-5) of this section, with the exceptions noted in [paragraphs (b)(6)(ii)(A) through (b)(6)(ii)(C)](#b-6-ii-A..b-6-ii-C) of this section.
      - (A) Selection of the location of the inlet sampling sites shall ensure the measurement of total organic HAP concentrations in all process vent streams and primary and secondary fuels introduced into the boiler or process heater.
      - (B) [Paragraph (b)(5)(iii)](#b-5-iii) of this section is applicable, except that TOC (minus methane and ethane) may be measured instead of total organic HAP.
      - (C) The mass rates shall be calculated in accordance with [paragraph (b)(5)(iv)](#b-5-iv) of this section, except that Cj at the inlet and outlet of the control device shall be the sum of all total organic HAP (or TOC, minus methane and ethane) concentrations for all process vent streams and primary and secondary fuels introduced into the boiler or process heater.
    - (iii) The control efficiency of the boiler or process heater shall be calculated using Equation 29.
    - (iv) The outlet total organic HAP emissions associated with the back-end process unit operation shall be calculated using Equation 30, as shown in [paragraph (b)(8)](#b-8) of this section.
  - (7) An owner or operator is not required to conduct a source test to determine the outlet organic HAP emissions if any control device specified in [paragraphs (b)(7)(i) through (b)(7)(vi)](#b-7-i..b-7-vi) of this section is used. For these devices, the inlet emissions associated with the back-end process unit operation shall be determined in accordance with [paragraph (b)(5)](#b-5) of this section, and the outlet emissions shall be calculated using the equation in [paragraph (b)(8)](#b-8) of this section.
    - (i) **A flare.**
      - (A) Except as specified in [paragraph (b)(7)(i)(B)](#b-7-i-B) of this section, the owner or operator shall demonstrate compliance as provided in [§ 63.504(c)](/cfr/40/63.504.md?p=c).
      - (B) For each affected source as described in [§ 63.480](/cfr/40/63.480.md), beginning no later than the compliance dates specified in [§ 63.481(n)](/cfr/40/63.481.md?p=n), [paragraph (b)(7)(i)(A)](#b-7-i-A) of this section no longer applies and instead the owner or operator of the affected source must comply with [§ 63.508](/cfr/40/63.508.md) for the flare.
    - (ii) **A boiler or process heater with a design heat input capacity of 44 megawatts or greater.**
    - (iii) A boiler or process heater into which the process vent stream is introduced with the primary fuel or is used as the primary fuel.
    - (iv) A control device for which a performance test was conducted for determining compliance with a regulation promulgated by the EPA and the test was conducted using the same Methods specified in this section and either no deliberate process changes have been made since the test, or the owner or operator can demonstrate that the results of the performance test, with or without adjustments, reliably demonstrate compliance despite process changes.
    - (v) **A boiler or process heater burning hazardous waste for which the owner or operator—**
      - (A) Has been issued a final permit under [40 CFR part 270](/cfr/40/part270.md) and complies with the requirements of [40 CFR part 266](/cfr/40/part266.md), [subpart H](/cfr/40/subpartH.md), or
      - (B) **Has certified compliance with the interim status requirements of 40 CFR part 266, subpart H.**
    - (vi) A hazardous waste incinerator for which the owner or operator has been issued a final permit under [40 CFR Part 270](/cfr/40/part270.md) and complies with the requirements of [40 CFR part 264](/cfr/40/part264.md), [subpart O](/cfr/40/subpartO.md), or has certified compliance with the interim status requirements of [40 CFR part 265](/cfr/40/part265.md), subpart O.
  - (8) If one of the control devices listed in paragraph [(b)(6)](#b-6) or [(b)(7)](#b-7) of this section is used, the outlet emissions shall be calculated using Equation 30.
    - (i) If a back-end process vent stream is introduced with the combustion air, or as a secondary fuel into a boiler or process heater with a design capacity less than 44 megawatts, the control efficiency of the boiler or process heater shall be determined using the procedures in [paragraph (b)(6)(iii)](#b-6-iii) of this section.
    - (ii) If a back-end process vent is controlled using a control device specified in [paragraph (b)(7)](#b-7) (i), (ii), (iii), or (v) of this section, the control device efficiency shall be assumed to be 98 percent.
    - (iii) If a back-end process vent is controlled using a control device specified in [paragraph (b)(7)(iv)](#b-7-iv) of this section, the control device efficiency shall be the efficiency determined in the previous performance test.
- (c) Compliance shall be determined using the procedures in this paragraph.
  - (1) For each test run, the residual organic HAP content, adjusted for the control or recovery device emission reduction, shall be calculated using Equation 31.
  - (2) A facility is in compliance if the average of the organic HAP contents calculated for all three test runs is below the residual organic HAP limitations in [§ 63.494(a)(1) through (3)](/cfr/40/63.494.md?p=a-1..a-3).
- (d) An owner or operator complying with the residual organic HAP limitations in [§ 63.494(a)(1) through (3)](/cfr/40/63.494.md?p=a-1..a-3) using a control or recovery device, shall redetermine the compliance status through the requirements described in [paragraph (b)](#b) of this section whenever process changes are made. The owner or operator shall report the results of the redetermination in accordance with [§ 63.499(d)](/cfr/40/63.499.md?p=d). For the purposes of this section, a process change is any action that would reasonably be expected to impair the performance of the control or recovery device. For the purposes of this section, the production of an elastomer with a residual organic HAP content greater than the residual organic HAP content of the elastomer used in the compliance demonstration constitutes a process change, unless the overall effect of the change is to reduce organic HAP emissions from the source as a whole. Other examples of process changes may include changes in production capacity or production rate, or removal or addition of equipment. For the purposes of this paragraph, process changes do not include: Process upsets; unintentional, temporary process changes; or changes that reduce the residual organic HAP content of the elastomer.

# §63.497. Back-end process provisions—monitoring provisions for control and recovery devices used to comply with residual organic HAP limitations.

- (a) An owner or operator complying with the residual organic HAP limitations in [§ 63.494(a)(1) through (3)](/cfr/40/63.494.md?p=a-1..a-3) using control or recovery devices, or a combination of stripping and control or recovery devices, shall install the monitoring equipment specified in [paragraphs (a)(1) through (7)](#a-1..a-7) of this section, as appropriate.
  - (1) Where an incinerator is used, a temperature monitoring device equipped with a continuous recorder is required.
    - (i) Where an incinerator other than a catalytic incinerator is used, the temperature monitoring device shall be installed in the firebox or in the ductwork immediately downstream of the firebox in a position before any substantial heat exchange occurs.
    - (ii) Where a catalytic incinerator is used, the temperature monitoring devices shall be installed in the gas stream immediately before and after the catalyst bed.
  - (2) Where a flare is used, except as specified in [paragraph (a)(7)](#a-7) of this section, a device (including, but not limited to, a thermocouple, ultra-violet beam sensor, or infrared sensor) capable of continuously detecting the presence of a pilot flame is required.
  - (3) Where a boiler or process heater of less than 44 megawatts design heat input capacity is used, a temperature monitoring device in the firebox equipped with a continuous recorder is required. Any boiler or process heater in which all vent streams are introduced with primary fuel or are used as the primary fuel is exempt from this requirement.
  - (4) For an absorber, a scrubbing liquid temperature monitoring device and a specific gravity monitoring device are required, each equipped with a continuous recorder.
  - (5) For a condenser, a condenser exit (product side) temperature monitoring device equipped with a continuous recorder is required.
  - (6) Except as specified in [paragraph (a)(8)](#a-8) of this section, for a carbon adsorber, an integrating regeneration steam flow, nitrogen flow, or pressure monitoring device having an accuracy of at least ±10 percent of the flow rate, level, or pressure, capable of recording the total regeneration steam flow or nitrogen flow, or pressure (gauge or absolute) for each regeneration cycle; and a carbon bed temperature monitoring device, capable of recording the carbon bed temperature after each regeneration and within 15 minutes of completing any cooling cycle are required.
  - (7) For each affected source as described in [§ 63.480](/cfr/40/63.480.md), beginning no later than the compliance dates specified in [§ 63.481(n)](/cfr/40/63.481.md?p=n), [paragraph (a)(2)](#a-2) of this section no longer applies and instead the owner or operator of the affected source must comply with [§ 63.508](/cfr/40/63.508.md) for the flare.
  - (8) Beginning no later than the compliance dates specified in [§ 63.481(n)](/cfr/40/63.481.md?p=n), if the owner or operator vents emissions through a closed vent system to an adsorber(s) that cannot be regenerated or a regenerative adsorber(s) that is regenerated offsite, then the owner or operator must install a system of two or more adsorber units in series and comply with the requirements specified in [paragraphs (a)(8)(i) through (iii)](#a-8-i..a-8-iii) of this section.
    - (i) Conduct an initial performance test or design evaluation of the adsorber and establish the breakthrough limit and adsorber bed life.
    - (ii) Monitor the HAP or total organic compound (TOC) concentration through a sample port at the outlet of the first adsorber bed in series according to the schedule in [paragraph (a)(8)(iii)(B)](#a-8-iii-B) of this section. The owner or operator must measure the concentration of HAP or TOC using either a portable analyzer, in accordance with Method 21 of [40 CFR part 60](/cfr/40/part60.md), appendix A-7 using methane, propane, isobutylene, or the primary HAP being controlled as the calibration gas or Method 25A of [40 CFR part 60](/cfr/40/part60.md), appendix A-7 using methane, propane, or the primary HAP being controlled as the calibration gas.
    - (iii) Comply with [paragraph (a)(8)(iii)(A)](#a-8-iii-A) of this section, and comply with the monitoring frequency according to [paragraph (a)(8)(iii)(B)](#a-8-iii-B) of this section.
      - (A) The first adsorber in series must be replaced immediately when breakthrough, as defined in [§ 63.482](/cfr/40/63.482.md), is detected between the first and second adsorber. The original second adsorber (or a fresh canister) will become the new first adsorber and a fresh adsorber will become the second adsorber. For purposes of this paragraph, “immediately” means within 8 hours of the detection of a breakthrough for adsorbers of 55 gallons or less, and within 24 hours of the detection of a breakthrough for adsorbers greater than 55 gallons. The owner or operator must monitor at the outlet of the first adsorber within 3 days of replacement to confirm it is performing properly.
      - (B) Based on the adsorber bed life established according to [paragraph (a)(8)(i)](#a-8-i) of this section and the date the adsorbent was last replaced, conduct monitoring to detect breakthrough at least monthly if the adsorbent has more than 2 months of life remaining, at least weekly if the adsorbent has between 2 months and 2 weeks of life remaining, and at least daily if the adsorbent has 2 weeks or less of life remaining.
- (b) An owner or operator may request approval to monitor parameters other than those required by [paragraph (a)](#a) of this section. The request shall be submitted according to the procedures specified in § [63.506(f)](/cfr/40/63.506.md?p=f) or [(g)](/cfr/40/63.506.md?p=g). Approval shall be requested if the owner or operator:
  - (1) Uses a control or recovery device other than those listed in [paragraph (a)](#a) of this section; or
  - (2) Uses one of the control or recovery devices listed in [paragraph (a)](#a) of this section, but seeks to monitor a parameter other than those specified in [paragraph (a)](#a) of this section.
- (c) The owner or operator shall establish a level, defined as either a maximum or minimum operating parameter, that indicates proper operation of the control or recovery device for each parameter monitored under [paragraphs (a)(1) through (a)(6)](#a-1..a-6) of this section. This level is determined in accordance with [§ 63.505](/cfr/40/63.505.md). The established level, along with supporting documentation, shall be submitted in the Notification of Compliance Status or the operating permit application, as required in § [63.506(e)(5)](/cfr/40/63.506.md?p=e-5) or [(e)(8)](/cfr/40/63.506.md?p=e-8), respectively. The owner or operator shall operate control and recovery devices so that the daily average value is above or below the established level, as required, to ensure continued compliance with the standard, except as otherwise stated in this subpart.
- (d) The owner or operator of an affected source with a controlled back-end process vent using a vent system that contains bypass lines that could divert a vent stream away from the control or recovery device used to comply with [§ 63.494(a)(1) through (3)](/cfr/40/63.494.md?p=a-1..a-3), shall comply with either paragraph [(d)(1)](#d-1) or [(d)(2)](#d-2), and [(d)(3)](#d-3) of this section. Except as specified in [paragraph (d)(3)](#d-3) of this section, equipment such as low leg drains, high point bleeds, analyzer vents, open-ended valves or lines, and pressure relief valves needed for safety purposes are not subject to this paragraph.
  - (1) Properly install, maintain, and operate a flow indicator that takes a reading at least once every 15 minutes. Records shall be generated as specified in [§ 63.498(d)(5)(iii)](/cfr/40/63.498.md?p=d-5-iii). The flow indicator shall be installed at the entrance to any bypass line that could divert the vent stream away from the control device to the atmosphere; or
  - (2) Secure the bypass line valve in the non-diverting position with a car-seal or a lock-and-key type configuration. A visual inspection of the seal or closure mechanism shall be performed at least once every month to ensure that the valve is maintained in the non-diverting position and the vent stream is not diverted through the bypass line.
  - (3) For each affected source as described in [§ 63.480](/cfr/40/63.480.md), beginning no later than the compliance dates specified in [§ 63.481(n)](/cfr/40/63.481.md?p=n):
    - (i) The use of a bypass line at any time on a closed vent system to divert emissions (subject to the emission standards in [§ 63.487](/cfr/40/63.487.md)) to the atmosphere or to a control device not meeting the requirements specified in this subpart is an emissions standards violation.
    - (ii) **The last sentence in paragraph (d) of this section no longer applies.** Instead, the exemptions specified in paragraph [(d)(3)(ii)(A)](#d-3-ii-A) and [(d)(3)(ii)(B)](#d-3-ii-B) of this section apply.
      - (A) Except for pressure relief devices subject to [§ 63.165(e)(4)](/cfr/40/63.165.md?p=e-4) of [subpart H](/cfr/40/subpartH.md) of this part, equipment such as low leg drains and equipment subject to the requirements of [subpart H](/cfr/40/subpartH.md) of this part are not subject to this [paragraph (d)](#d) of this section.
      - (B) Open-ended valves or lines that use a cap, blind flange, plug, or second valve and follow the requirements specified in 40 CFR [60.482-6(a)(2)](/cfr/40/60.482-6.md?p=a-2), [(b)](/cfr/40/60.482-6.md?p=a-b), and [(c)](/cfr/40/60.482-6.md?p=a-c) or follow requirements codified in another regulation that are the same as 40 CFR [60.482-6(a)(2)](/cfr/40/60.482-6.md?p=a-2), [(b)](/cfr/40/60.482-6.md?p=a-b), and [(c)](/cfr/40/60.482-6.md?p=a-c) are not subject to this [paragraph (d)](#d) of this section.

# §63.498. Back-end process provisions—recordkeeping.

- (a) Each owner or operator shall maintain the records specified in [paragraphs (a)(1) through (4)](#a-1..a-4), and [paragraphs (b) through (f)](#b..f) of this section, as appropriate.
  - (1) **The type of elastomer product processed in the back-end operation.**
  - (2) The type of process (solution process, emulsion process, etc.)
  - (3) If the back-end process operation is subject to a residual organic HAP limitation in [§ 63.494(a)(1) through (3)](/cfr/40/63.494.md?p=a-1..a-3), whether compliance will be achieved by stripping technology, or by control or recovery devices.
  - (4) If the back-end process operation is subject to an emission limitation in [§ 63.494(a)(4)](/cfr/40/63.494.md?p=a-4), the organic HAP emission limitation calculated in accordance with [§ 63.494(a)(4)(i) through (iv)](/cfr/40/63.494.md?p=a-4-i..a-4-iv), as applicable.
- (b) Each owner or operator of a back-end process operation using stripping technology to comply with a residual organic HAP limitation in [§ 63.494(a)(1) through (3)](/cfr/40/63.494.md?p=a-1..a-3), and demonstrating compliance using the periodic sampling procedures in [§ 63.495(b)](/cfr/40/63.495.md?p=b), shall maintain the records specified in [paragraph (b)(1)](#b-1), and in [paragraph (b)(2)](#b-2) or [paragraph (b)(3)](#b-3) of this section, as appropriate.
  - (1) Records associated with each sample taken in accordance with [§ 63.495(b)](/cfr/40/63.495.md?p=b). These records shall include the following for each sample:
    - (i) Elastomer type,
    - (ii) The date and time the sample was collected,
    - (iii) **The corresponding quantity of elastomer processed over the time period represented by the sample.** Acceptable methods of determining this quantity are production records, measurement of stream characteristics, and engineering calculations.
      - (A) For emulsion processes, this quantity shall be the weight of the latex leaving the stripper.
      - (B) For solution processes, this quantity shall be the crumb rubber dry weight of the rubber leaving the stripper.
    - (iv) **The organic HAP content of each sample.**
  - (2) The monthly weighted average organic HAP content, calculated in accordance with [§ 63.495(f)](/cfr/40/63.495.md?p=f).
  - (3) If the organic HAP contents for all samples analyzed during a month are below the appropriate level in [§ 63.494(a)](/cfr/40/63.494.md?p=a), the owner or operator may record that all samples were in accordance with the residual organic HAP limitations in [§ 63.494(a)(1) through (3)](/cfr/40/63.494.md?p=a-1..a-3), rather than calculating and recording a monthly weighted average.
- (c) Each owner or operator of a back-end process operation using stripping technology to comply with a residual organic HAP limitation in [§ 63.494(a)(1) through (3)](/cfr/40/63.494.md?p=a-1..a-3), and demonstrating compliance using the stripper parameter monitoring procedures in [§ 63.495(c)](/cfr/40/63.495.md?p=c), shall maintain the records specified in [paragraphs (c)(1) through (3)](#c-1..c-3) of this section.
  - (1) Records associated with the initial, and subsequent, determinations of the organic HAP content of each grade of elastomer produced. These records shall include the following:
    - (i) An identification of the elastomer type and grade;
    - (ii) The results of the residual organic HAP analyses, conducted in accordance with [§ 63.505(e)(1)](/cfr/40/63.505.md?p=e-1);
    - (iii) The stripper monitoring parameters required to be established in [§ 63.495(c)(1)](/cfr/40/63.495.md?p=c-1).
    - (iv) If re-determinations are made of the organic HAP content, and re-establishment of the stripper monitoring parameters, records of the initial determination are no longer required to be maintained.
  - (2) **Records associated with each grade or batch.** These records shall include the following for each grade or batch:
    - (i) Elastomer type and grade;
    - (ii) The quantity of elastomer processed;
      - (A) For emulsion processes, this quantity shall be the weight of the latex leaving the stripper.
      - (B) For solution processes, this quantity shall be the crumb rubber dry weight of the crumb rubber leaving the stripper.
    - (iii) The hourly average of all stripper parameter results;
    - (iv) If one or more hourly average stripper monitoring parameters is not in accordance with the established levels, the results of the residual organic HAP analysis.
  - (3) The monthly weighted average organic HAP content, calculated in accordance with [§ 63.495(f)](/cfr/40/63.495.md?p=f).
- (d) Each owner or operator of a back-end process operation using control or recovery devices to comply with a residual organic HAP limitation in [§ 63.494(a)(1) through (3)](/cfr/40/63.494.md?p=a-1..a-3), shall maintain the records specified in [paragraphs (d)(1) through (5)](#d-1..d-5) of this section. The recordkeeping requirements contained in [paragraphs (d)(1) through (4)](#d-1..d-4) pertain to the results of the testing required by [§ 63.496(b)](/cfr/40/63.496.md?p=b), for each of the three required test runs.
  - (1) The uncontrolled residual organic HAP content in the latex or dry crumb rubber, as required to be determined by [§ 63.496(b)(3)](/cfr/40/63.496.md?p=b-3), including the test results of the analysis;
  - (2) The total quantity of material (weight of latex or dry crumb rubber) processed during the test run, recorded in accordance with [§ 63.496(b)(4)](/cfr/40/63.496.md?p=b-4);
  - (3) The organic HAP emissions at the inlet and outlet of the control or recovery device, determined in accordance with [§ 63.496(b)(5) through (8)](/cfr/40/63.496.md?p=b-5..b-8), including all test results and calculations.
  - (4) The residual organic HAP content, adjusted for the control or recovery device emission reduction, determined in accordance with [§ 63.496(c)(1)](/cfr/40/63.496.md?p=c-1).
  - (5) Each owner or operator using a control or recovery device shall keep the following records readily accessible:
    - (i) Continuous records of the equipment operating parameters specified to be monitored under [§ 63.497(a)](/cfr/40/63.497.md?p=a) or specified by the Administrator in accordance with [§ 63.497(b)](/cfr/40/63.497.md?p=b). For flares, the records specified in [§ 63.508](/cfr/40/63.508.md), if applicable, and table 3 to [subpart G](/cfr/40/subpartG.md) of this part shall be maintained in place of continuous records.
    - (ii) Records of the daily average value of each continuously monitored parameter for each operating day, except as provided in [paragraphs (d)(5)(ii)(D) through (d)(5)(ii)(F)](#d-5-ii-D..d-5-ii-F) of this section.
      - (A) The daily average shall be calculated as the average of all values for a monitored parameter recorded during the operating day, except as provided in [paragraph (d)(5)(ii)(B)](#d-5-ii-B) of this section. The average shall cover a 24-hour period if operation is continuous, or the number of hours of operation per operating day if operation is not continuous.
      - (B) Monitoring data recorded during periods of monitoring system breakdowns, repairs, calibration checks, and zero (low-level) and high-level adjustments, shall not be included in computing the hourly or daily averages. In addition, monitoring data recorded during periods of non-operation of the EPPU (or specific portion thereof) resulting in cessation of organic HAP emissions, shall not be included in computing the hourly or daily averages. Records shall be kept of the times and durations of all such periods and any other periods of process or control device operation when monitors are not operating.
      - (C) The operating day shall be the period defined in the operating permit or the Notification of Compliance Status in § [63.506(e)(5)](/cfr/40/63.506.md?p=e-5) or [(8)](/cfr/40/63.506.md?p=e-8). It may be from midnight to midnight or another 24-hour period.
      - (D) If all recorded values for a monitored parameter during an operating day are below the maximum, or above the minimum, level established in the Notification of Compliance Status in [§ 63.506(e)(5)](/cfr/40/63.506.md?p=e-5) or in the operating permit, the owner or operator may record that all values were below the maximum or above the minimum level, rather than calculating and recording a daily average for that operating day.
      - (E) Except as specified in [paragraph (d)(5)(ii)(F)](#d-5-ii-F) of this section, for flares, records of the times and duration of all periods during which the pilot flame is absent, shall be kept rather than daily averages. The records specified in this paragraph are not required during periods when emissions are not routed to the flare.
      - (F) For each affected source as described in [§ 63.480](/cfr/40/63.480.md), beginning no later than the compliance dates specified in [§ 63.481(n)](/cfr/40/63.481.md?p=n), [paragraph (d)(5)(ii)(E)](#d-5-ii-E) of this section no longer applies and instead the owner or operator of the affected source must keep the records specified in [§ 63.108(m)](/cfr/40/63.108.md?p=m) of [subpart F](/cfr/40/subpartF.md) of this part and [§ 63.508](/cfr/40/63.508.md).
    - (iii) Except as specified in [paragraph (d)(5)(v)](#d-5-v) of this section, hourly records of whether the flow indicator specified under [§ 63.497(d)(1)](/cfr/40/63.497.md?p=d-1) was operating and whether a diversion was detected at any time during the hour, as well as records of the times of all periods when the vent stream is diverted from the control device or the flow indicator is not operating.
    - (iv) Except as specified in [paragraph (d)(5)(v)](#d-5-v) of this section, where a seal mechanism is used to comply with [§ 63.497(d)(2)](/cfr/40/63.497.md?p=d-2), hourly records of flow are not required.
      - (A) For compliance with [§ 63.497(d)(2)](/cfr/40/63.497.md?p=d-2), the owner or operator shall record whether the monthly visual inspection of the seals or closure mechanisms has been done, and shall record instances when the seal mechanism is broken, the bypass line damper or valve position has changed, or the key for a lock-and-key type configuration has been checked out, and records of any car-seal that has broken.
      - (B) [Reserved]
    - (v) For each flow event from a bypass line subject to the requirements in [§ 63.127(d)](/cfr/40/63.127.md?p=d) of [subpart G](/cfr/40/subpartG.md) of this part for each affected source as described in [§ 63.480](/cfr/40/63.480.md), beginning no later than the compliance dates specified in [§ 63.481(n)](/cfr/40/63.481.md?p=n), the owner or operator must also maintain records sufficient to determine whether or not the detected flow included flow requiring control. For each flow event from a bypass line requiring control that is released either directly to the atmosphere or to a control device not meeting the requirements in this subpart, the owner or operator must include an estimate of the volume of gas, the concentration of organic HAP in the gas and the resulting emissions of organic HAP that bypassed the control device using process knowledge and engineering estimates.
- (e) If the back-end process operation is subject to an organic HAP emission limitation in [§ 63.494(a)(4)](/cfr/40/63.494.md?p=a-4), the records specified in [paragraphs (e)(1) through (4)](#e-1..e-4) of this section.
  - (1) The applicable organic HAP emission limitation determined in accordance with [§ 63.494(a)(4)(i) through (iv)](/cfr/40/63.494.md?p=a-4-i..a-4-iv).
  - (2) The organic HAP emissions from all back-end process operations for each month, along with documentation of all calculations and other information used in the engineering assessment to estimate these emissions.
  - (3) **The mass of elastomer product produced each month.**
  - (4) The total mass of organic HAP emitted for each 12-month period divided by the total mass of elastomer produced during the 12-month period, determined in accordance with [§ 63.495(g)(5)](/cfr/40/63.495.md?p=g-5).
- (f) Owners and operators subject to [§ 63.494(a)(7)](/cfr/40/63.494.md?p=a-7), must keep the records specified in paragraphs [(f)(1)](#f-1) and [(2)](#f-2) of this section in addition to those records specified elsewhere in this section.
  - (1) For back-end process vents in chloroprene service, include all uncontrolled, undiluted chloroprene concentration measurements, and the calculations used to determine the total uncontrolled chloroprene mass emission rate for the sum of all vent gas streams.
  - (2) The owner or operator must keep records of all periods during which operating values are outside of the applicable operating limits specified in [§ 63.510(b)(4) through (6)](/cfr/40/63.510.md?p=b-4..b-6) when regulated material is being routed to the non-flare control device. The record must specify the operating parameter, the applicable limit, and the highest (for maximum operating limits) or lowest (for minimum operating limits) value recorded during the period.

# §63.499. Back-end process provisions—reporting.

- (a) The owner or operator of an affected source with back-end process operations shall submit the information required in [paragraphs (a)(1) through (a)(3)](#a-1..a-3) of this section, for each back-end process operation at the affected source, as part of the Notification of Compliance Status specified in [§ 63.506(e)(5)](/cfr/40/63.506.md?p=e-5).
  - (1) **The type of elastomer product processed in the back-end operation.**
  - (2) The type of process (solution process, emulsion process, etc.)
  - (3) If the back-end process operation is subject to a residual organic HAP limitation in [§ 63.494(a)(1) through (3)](/cfr/40/63.494.md?p=a-1..a-3), whether compliance will be achieved by stripping technology, or by control or recovery devices.
- (b) Each owner or operator of a back-end process operation using stripping to comply with a residual organic HAP limitation in [§ 63.494(a)(1) through (3)](/cfr/40/63.494.md?p=a-1..a-3), and demonstrating compliance by stripper parameter monitoring, shall submit reports as specified in paragraphs [(b)(1)](#b-1) and [(2)](#b-2) of this section.
  - (1) As part of the Notification of Compliance Status specified in [§ 63.506(e)(5)](/cfr/40/63.506.md?p=e-5), the owner or operator shall submit the information specified in [§ 63.498(c)(1)](/cfr/40/63.498.md?p=c-1).
  - (2) For organic HAP content/stripper monitoring parameter re-determinations, and the addition of new grades, the information specified in [§ 63.498(c)(1)](/cfr/40/63.498.md?p=c-1) shall be submitted in the next periodic report specified in [§ 63.506(e)(6)](/cfr/40/63.506.md?p=e-6).
- (c) Each owner or operator of an affected source with a back-end process operation control or recovery device that shall comply with a residual organic HAP limitation in [§ 63.494(a)(1) through (3)](/cfr/40/63.494.md?p=a-1..a-3), shall submit the information specified in [paragraphs (c)(1) through (3)](#c-1..c-3) of this section as part of the Notification of Compliance Status specified in [§ 63.506(e)(5)](/cfr/40/63.506.md?p=e-5).
  - (1) The residual organic HAP content, adjusted for the control or recovery device emission reduction, determined in accordance with [§ 63.496(c)(1)](/cfr/40/63.496.md?p=c-1), for each test run in the compliance determination.
  - (2) The operating parameter level established in accordance with [§ 63.497(c)](/cfr/40/63.497.md?p=c), along with supporting documentation.
  - (3) The information specified in [paragraphs (c)(3)(i)](#c-3-i) when using a flare, and the information specified in [paragraph (c)(3)(ii)](#c-3-ii) of this section when using a boiler or process heater.
    - (i) The flare design (i.e., steam-assisted, air-assisted, or non-assisted); all visible emission readings, heat content determinations, flow rate measurements, and exit velocity determinations made during the compliance determination; and all periods during the compliance determination when the pilot flame is absent.
    - (ii) A description of the location at which the vent stream is introduced into the boiler or process heater.
- (d) Whenever a process change, as defined in [§ 63.496(d)](/cfr/40/63.496.md?p=d), is made that causes the redetermination of the compliance status for the back-end process operations subject to a residual organic HAP limitation in [§ 63.494(a)(1) through (3)](/cfr/40/63.494.md?p=a-1..a-3), the owner or operator shall submit a report within 180 days after the process change, as specified in [§ 63.506(e)(7)(iii)](/cfr/40/63.506.md?p=e-7-iii). The report shall include:
  - (1) A description of the process change;
  - (2) The results of the redetermination of the compliance status, determined in accordance with [§ 63.496(b)](/cfr/40/63.496.md?p=b), and recorded in accordance with [§ 63.498(d)(1)](/cfr/40/63.498.md?p=d-1), and
  - (3) Documentation of the re-establishment of a parameter level for the control or recovery device, defined as either a maximum or minimum operating parameter, that indicates proper operation of the control or recovery device, in accordance with [§ 63.497(c)](/cfr/40/63.497.md?p=c) and recorded in accordance with [§ 63.498(d)(2)](/cfr/40/63.498.md?p=d-2).
- (e) If an owner or operator uses a control or recovery device other than those listed in [§ 63.497(a)](/cfr/40/63.497.md?p=a) or requests approval to monitor a parameter other than those specified in [§ 63.497(a)](/cfr/40/63.497.md?p=a), the owner or operator shall submit a description of planned reporting and recordkeeping procedures as required under § [63.506(e)(3)](/cfr/40/63.506.md?p=e-3) or [(e)(8)](/cfr/40/63.506.md?p=e-8). The Administrator will specify appropriate reporting and recordkeeping requirements as part of the review of the Precompliance Report or Operating Permit application.
- (f) If the back-end process operation is subject to an organic HAP emission limitation in [§ 63.494(a)(4)](/cfr/40/63.494.md?p=a-4), the owner and operator must submit the information specified in paragraphs [(f)(1)](#f-1) and [(2)](#f-2) of this section.
  - (1) The applicable organic HAP emission limitation determined in accordance with [§ 63.494(a)(4)(i) through (iv)](/cfr/40/63.494.md?p=a-4-i..a-4-iv), shall be submitted no later than 180 days from the date of publication of the final rule amendments in the Federal Register.
  - (2) Beginning with the first periodic report required to be submitted by [§ 63.506(e)(6)](/cfr/40/63.506.md?p=e-6) that is at least 13 months after the compliance date, the total mass of organic HAP emitted for each of the rolling 12-month periods in the reporting period divided by the total mass of elastomer produced during the corresponding 12-month period, determined in accordance with [§ 63.495(g)(5)](/cfr/40/63.495.md?p=g-5).
- (g) Owners and operators subject to [§ 63.494(a)(7)](/cfr/40/63.494.md?p=a-7), must include in the periodic report, the records for the periods specified in [§ 63.498(f)(2)](/cfr/40/63.498.md?p=f-2). Indicate the start date, start time and duration in hours for each period.

# §63.500. Back-end process provisions—carbon disulfide limitations for styrene butadiene rubber by emulsion processes.

- (a) Owners or operators of sources subject to this subpart producing styrene butadiene rubber using an emulsion process shall operate the process such that the carbon disulfide concentration in each crumb dryer exhausts shall not exceed 45 ppmv.
  - (1) The owner or operator shall develop standard operating procedures for the addition of sulfur containing shortstop agents to ensure that the limitation in [paragraph (a)](#a) of this section is maintained. There shall be a standard operating procedure representing the production of every grade of styrene butadiene rubber produced at the affected source using a sulfur containing shortstop agent.
  - (2) A validation of each standard operating procedure shall be conducted in accordance with [paragraph (c)](#c) of this section, except as provided in [paragraph (b)](#b) of this section, to demonstrate compliance with the limitation in [paragraph (a)](#a) of this section.
  - (3) The owner or operator shall operate the process in accordance with a validated standard operating procedure at all times when styrene butadiene rubber is being produced using a sulfur containing shortstop agent. If a standard operating procedure is changed, it shall be re-validated.
  - (4) Records specified in [paragraph (d)](#d) of this section shall be maintained.
  - (5) Reports shall be submitted in accordance with [paragraph (e)](#e) of this section.
- (b) **Crumb dryers that are vented to a combustion device are not subject to the provisions in this section.**
- (c) The owner or operator shall validate each standard operating procedure to determine compliance with the limitation in [paragraph (a)](#a) of this section using the testing procedures in [paragraph (c)(1)](#c-1) of this section or engineering assessment, as described in [paragraph (c)(2)](#c-2) of this section.
  - (1) The owner or operator may choose to conduct a performance test, using the procedures in [paragraphs (c)(1)(i) through (c)(1)(iii)](#c-1-i..c-1-iii) of this section to demonstrate compliance with the carbon disulfide concentration limitation in [paragraph (a)](#a) of this section. One test shall be conducted for each standard operating procedure.
    - (i) Method 1 or 1A of [40 CFR part 60](/cfr/40/part60.md), appendix A, as required, shall be used for selection of the sampling sites.
    - (ii) The gas volumetric flow rate shall be determined using Method 2, 2A, 2C, or 2D of [40 CFR part 60](/cfr/40/part60.md), appendix A, as required.
    - (iii) To determine compliance with the carbon disulfide concentration limit in [paragraph (a)](#a) of this section, the owner or operator shall use Method 18 or Method 25A of appendices A-6 and A-7 to [40 CFR part 60](/cfr/40/part60.md), respectively to measure carbon disulfide. ASTM D6420-18 (incorporated by reference, see [§ 63.14](/cfr/40/63.14.md)) may also be used in lieu of Method 18, if the target compounds are all known and are all listed in [Section 1.1](/cfr/40/1.1.md) of ASTM D6420-18 as measurable; ASTM D6420-18 must not be used for methane and ethane; and ASTM D6420-18 may not be used as a total VOC method. Alternatively, any other method or data that has been validated according to the applicable procedures in Method 301 of appendix A to this part, may be used. The following procedures shall be used to calculate carbon disulfide concentration:
      - (A) The minimum sampling time for each run shall be 1 hour, in which either an integrated sample or a minimum of four grab samples shall be taken. If grab sampling is used, then the samples shall be taken at approximately equal intervals in time, such as 15 minute intervals during the run.
      - (B) The concentration of carbon disulfide shall be calculated using Equation 32.
  - (2) The owner or operator may use engineering assessment to demonstrate compliance with the carbon disulfide concentration limitation in [paragraph (a)](#a) of this section. Engineering assessment includes, but is not limited to, the following:
    - (i) Previous test results, provided the tests are representative of current operating practices at the process unit.
    - (ii) Bench-scale or pilot-scale test data representative of the process under representative operating conditions.
    - (iii) Flow rate and/or carbon disulfide emission rate specified or implied within an applicable permit limit.
    - (iv) Design analysis based on accepted chemical engineering principles, measurable process parameters, or physical or chemical laws or properties. Examples of analytical methods include, but are not limited to:
      - (A) Use of material balances,
      - (B) Estimation of flow rate based on physical equipment design such as pump or blower capacities, and
      - (C) **Estimation of carbon disulfide concentrations based on saturation conditions.**
    - (v) All data, assumptions, and procedures used in the engineering assessment shall be documented.
- (d) Owners and operators of sources subject to this section shall maintain the records specified in paragraphs [(d)(1)](#d-1) and [(d)(2)](#d-2) of this section.
  - (1) **Documentation of the results of the testing required by paragraph (c) of this section.**
  - (2) **A description of the standard operating procedure used during the testing.** This description shall include, at a minimum, an identification of the sulfur containing shortstop agent added to the styrene butadiene rubber prior to the dryers, an identification of the point and time in the process where the sulfur containing shortstop agent is added, and an identification of the amount of sulfur containing shortstop agent added per unit of latex.
- (e) Owners and operators shall submit the reports as specified in paragraphs [(e)(1)](#e-1) and [(e)(2)](#e-2) of this section.
  - (1) As part of the Notification of Compliance Status specified in [§ 63.506(e)(5)](/cfr/40/63.506.md?p=e-5), documentation of the results of the testing required by [paragraph (c)](#c) of this section.
  - (2) If changes are made in the standard operating procedure used during the compliance test and recorded in accordance with [paragraph (d)(2)](#d-2) of this section, and if those changes have the potential for increasing the concentration of carbon disulfide in the crumb dryer exhaust to above the 45 ppmv limit, the owner or operator shall:
    - (i) Redetermine compliance using the test procedures in [paragraph (c)](#c) of this section, and
    - (ii) Submit documentation of the testing results in the next periodic report required by [§ 63.506(e)(6)](/cfr/40/63.506.md?p=e-6).