---
kind: "section"
citation: "40 C.F.R. § 63.683"
title: "40"
number: "63.683"
heading: "Standards: General."
url: "https://uscodex.org/cfr/40/63.683"
---

# §63.683. Standards: General.

- (a) The general standards under this section apply to owners and operators of affected sources as designated in [§ 63.680(c)](/cfr/40/63.680.md?p=c) of this subpart.
- (b) **Off-site material management units.**
  - (1) For each off-site material management unit that is part of an affected source, the owner or operator must meet the requirements in either paragraph [(b)(1)(i)](#b-1-i), [(b)(1)(ii)](#b-1-ii), or [(b)(1)(iii)](#b-1-iii) of this section except for those off-site material management units exempted under [paragraph (b)(2)](#b-2) of this section.
    - (i) The owner or operator controls air emissions from the off-site material management unit in accordance with the applicable standards specified in [§§ 63.685 through 63.689](/cfr/40/63.685..63.689.md) of this subpart.
    - (ii) The owner or operator removes or destroys HAP in the off-site material before placing the material in the off-site material management unit by treating the material in accordance with the standards specified in [§ 63.684](/cfr/40/63.684.md) of this subpart.
    - (iii) The owner or operator determines before placing off-site material in the off-site material management unit that the average VOHAP concentration of the off-site material is less than 500 parts per million by weight (ppmw) at the point-of-delivery. The owner or operator must perform an initial determination of the average VOHAP concentration of the off-site material using the procedures specified in [§ 63.694(b)](/cfr/40/63.694.md?p=b) of this subpart. This initial determination must be performed either before the first time any portion of the off-site material stream is placed in the unit or by the compliance date, whichever date is later. Thereafter, the owner or operator must review and update, as necessary, this determination at least once every calendar year following the date of the initial determination for the off-site material stream.
  - (2) An off-site material management unit is exempted from the requirements in [paragraph (b)(1)](#b-1) of this section when the owner or operator meets one of the exemptions provided in [paragraphs (b)(2)(i) through (b)(2)(iv)](#b-2-i..b-2-iv) of this section as applicable to the unit.
    - (i) An off-site material management unit is exempted from the requirements in [paragraph (b)(1)](#b-1) of this section if the off-site material management unit is also subject to another subpart under 40 CFR part [63](/cfr/40/part63.md) or [40](/cfr/40/part40.md) CFR [part 61](/cfr/40/part61.md), and the owner or operator is controlling the HAP listed in Table 1 of this subpart that are emitted from the unit in compliance with the provisions specified in the other applicable subpart under [part 61](/cfr/40/part61.md) or [part 63](/cfr/40/part63.md).
    - (ii) At the discretion of the owner or operator, one or a combination of off-site material management units may be exempted from the requirements in [paragraph (b)(1)](#b-1) of this section when these units meet the condition that the total annual quantity of HAP contained in the off-site material placed in the units exempted under this [paragraph (b)(2)(ii)](#b-2-ii) is less than 1 megagram per year. For the off-site material management units selected by the owner or operator to be exempted from the requirements in [paragraph (b)(1)](#b-1) of this section, the owner or operator must meet the requirements in paragraphs [(b)(2)(ii)(A)](#b-2-ii-A) and [(b)(2)(ii)(B)](#b-2-ii-B) of this section. An owner or operator may change the off-site material management units selected to be exempted under this [paragraph (b)(2)(ii)](#b-2-ii) by preparing a new designation for the exempt-units as required by [paragraph (b)(2)(ii)(A)](#b-2-ii-A) of this section and performing a new determination as required by [paragraph (b)(2)(ii)(B)](#b-2-ii-B) of this section.
      - (A) The owner or operator must designate each of the off-site material management units selected by the owner or operator to be exempt under [paragraph (b)(2)(ii)](#b-2-ii) of this section by either submitting to the Administrator a written notification identifying the exempt-units or permanently marking the exempt-units at the plant site. If an owner or operator chooses to prepare and submit a written notification, this notification must include a site plan, process diagram, or other appropriate documentation identifying each of the exempt-units. If an owner or operator chooses to permanently mark the exempt-units, each exempt-unit must be marked in such a manner that it can be readily identified as an exempt-unit from the other off-site material management units located at the plant site.
      - (B) The owner or operator must prepare an initial determination of the total annual HAP quantity in the off-site material placed in the units exempted under this [paragraph (b)(2)(ii)](#b-2-ii). This determination is based on the total quantity of the HAP listed in Table 1 of this subpart as determined at the point where the off-site material is placed in each exempted unit. The owner or operator must perform a new determination whenever the extent of changes to the quantity or composition of the off-site material placed in the exempted units could cause the total annual HAP content in the off-site material to exceed 1 megagram per year. The owner or operator must maintain documentation to support the most recent determination of the total annual HAP quantity. This documentation must include the basis and data used for determining the HAP content of the off-site material.
    - (iii) A tank or surface impoundment is exempted from the requirements in [paragraph (b)(1)](#b-1) of this section if the unit is used for a biological treatment process that meets the requirements in either paragraph [(b)(2)(iii)(A)](#b-2-iii-A) or [(b)(2)(iii)(B)](#b-2-iii-B) of this section and the owner or operator complies with the monitoring requirements in [§ 63.684(e)(4)](/cfr/40/63.684.md?p=e-4) of this subpart.
      - (A) The HAP biodegradation efficiency (Rbio) for the biological treatment process is equal to or greater than 95 percent. The HAP biodegradation efficiency (Rbio) shall be determined in accordance with the requirements of [§ 63.694(h)](/cfr/40/63.694.md?p=h) of this subpart.
      - (B) The total actual HAP mass removal rate (MRbio) for the off-site material treated by the biological treatment process is equal to or greater than the required HAP mass removal rate (RMR) for the off-site material. The total actual HAP mass removal rate (MRbio) must be determined in accordance with the requirements of [§ 63.694(i)](/cfr/40/63.694.md?p=i) of this subpart. The required HAP mass removal rate (RMR) must be determined in accordance with the requirements of [§ 63.694(e)](/cfr/40/63.694.md?p=e) of this subpart.
    - (iv) An off-site material management unit is exempted from the requirements in [paragraph (b)(1)](#b-1) of this section if the off-site material placed in the unit is a hazardous waste that meets the conditions specified in either paragraph [(b)(2)(iv)(A)](#b-2-iv-A) or [(b)(2)(iv)(B)](#b-2-iv-B) of this section.
      - (A) The hazardous waste meets the numerical organic concentration limits, applicable to the hazardous waste, as specified in [40 CFR part 268](/cfr/40/part268.md)—Land Disposal Restrictions, listed in the table, “Treatment Standards for Hazardous Waste” in [40 CFR 268.40](/cfr/40/268.40.md).
      - (B) The organic hazardous constituents in the hazardous waste have been treated by the treatment technology established by the EPA for the hazardous waste in [40 CFR 268.42(a)](/cfr/40/268.42.md?p=a), or have been removed or destroyed by an equivalent method of treatment approved by the EPA under [40 CFR 268.42(b)](/cfr/40/268.42.md?p=b).
    - (v) A tank used for bulk feed of off-site material to a waste incinerator is exempted from the requirements specified in [paragraph (b)(1)](#b-1) of this section if the tank meets all of the conditions specified in [paragraphs (b)(2)(v)(A) through (b)(2)(v)(C)](#b-2-v-A..b-2-v-C) of this section.
      - (A) The tank is located inside an enclosure vented to a control device that is designed and operated in accordance with all applicable requirements specified under [40 CFR part 61](/cfr/40/part61.md), [subpart FF](/cfr/40/subpartFF.md)—National Emission Standards for Benzene Waste Operations for a facility at which the total annual benzene quantity from the facility waste is equal to or greater than 10 megagrams per year;
      - (B) The enclosure and control device serving the tank were installed and began operation prior to July 1, 1996; and
      - (C) The enclosure is designed and operated in accordance with the criteria for a permanent total enclosure as specified in “Procedure T—Criteria for and Verification of a Permanent or Temporary Total Enclosure” under [40 CFR 52.741](/cfr/40/52.741.md), appendix B. The enclosure may have permanent or temporary openings to allow worker access; passage of material into or out of the enclosure by conveyor, vehicles, or other mechanical or electrical equipment; or to direct air flow into the enclosure. The owner or operator must annually perform the verification procedure for the enclosure as specified in [Section 5.0](/cfr/40/5.0.md) to “Procedure T—Criteria for and Verification of a Permanent or Temporary Total Enclosure.”
- (c) **Process vents.**
  - (1) For each process vent that is part of an affected source, the owner or operator must meet the requirements in either paragraph [(c)(1)(i)](#c-1-i) or [(c)(1)(ii)](#c-1-ii) of this section except for those process vents exempted under [paragraph (c)(2)](#c-2) of this section.
    - (i) The owner or operator controls air emissions from the process vent in accordance with the standards specified in [§ 63.690](/cfr/40/63.690.md) of this subpart.
    - (ii) The owner or operator determines before placing off-site material in the process equipment associated with the process vent that the average VOHAP concentration of the off-site material is less than 500 ppmw at the point-of-delivery. The owner or operator must perform an initial determination of the average VOHAP concentration of the off-site material using the procedures specified in [§ 63.694(b)](/cfr/40/63.694.md?p=b) of this subpart before any portion of the off-site material stream is placed in the unit. Thereafter, the owner or operator must review and update, as necessary, this determination at least once every calendar year following the date of the initial determination for the off-site material stream.
  - (2) A process vent is exempted from the requirements of [paragraph (c)(1)](#c-1) of this section when the owner or operator meets one of the exemptions provided in [paragraphs (c)(2)(i) through (c)(2)(iii)](#c-2-i..c-2-iii) of this section.
    - (i) A process vent is exempted from the requirements in [paragraph (c)(1)](#c-1) of this section if the process vent is also subject to another subpart under part [63](/cfr/40/part63.md) or [40](/cfr/40/part40.md) CFR [part 61](/cfr/40/part61.md), and the owner or operator is controlling the HAP listed in Table 1 of this subpart that are emitted from the process vent in compliance with the provisions specified in the other applicable subpart under [part 61](/cfr/40/part61.md) or [part 63](/cfr/40/part63.md).
    - (ii) A process vent is exempted from the requirements specified in [paragraph (c)(1)](#c-1) of this section if the owner or operator determines that the process vent stream flow rate is less than 0.005 cubic meters per minute (m 3/min) at standard conditions (as defined in [40 CFR 63.2](/cfr/40/63.2.md)). The process vent stream flow rate shall be determined in accordance with the procedures specified in [§ 63.694(m)](/cfr/40/63.694.md?p=m) of this subpart. Documentation must be prepared by the owner or operator and maintained at the plant site to support the determination of the process vent stream flow rate. This documentation must include identification of each process vent exempted under this paragraph and the test results used to determine the process vent stream flow rate.
    - (iii) A process vent is exempted from the requirements specified in [paragraph (c)(1)](#c-1) of this section if the owner or operator determines that the process vent stream flow rate is less than 6.0 m 3/min at standard conditions (as defined in [40 CFR 63.2](/cfr/40/63.2.md)) and the total HAP concentration is less than 20 ppmv. The process vent stream flow rate and total HAP concentration shall be determined in accordance with the procedures specified in [§ 63.694(m)](/cfr/40/63.694.md?p=m) of this subpart. Documentation must be prepared by the owner or operator and maintained at the plant site to support the determination of the process vent stream flow rate and total HAP concentration. This documentation must include identification of each process vent exempted under this [paragraph (c)(2)(iii)](#c-2-iii) and the test results used to determine the process vent stream flow rate and total HAP concentration. The owner or operator must perform a new determination of the process vent stream flow rate and total HAP concentration when the extent of changes to operation of the unit on which the process vent is used could cause either the process vent stream flow rate to exceed the limit of 6.0 m 3/min or the total HAP concentration to exceed the limit of 20 ppmv.
- (d) **Equipment leaks.** The owner or operator must control equipment leaks from each equipment component that is part of the affected source specified in [§ 63.680(c)(3)](/cfr/40/63.680.md?p=c-3) of this subpart by implementing leak detection and control measures in accordance with the standards specified in [§ 63.691](/cfr/40/63.691.md) of this subpart.
- (e) **General duty.** At all times, the owner or operator must operate and maintain any affected source, including associated air pollution control equipment and monitoring equipment, in a manner consistent with safety and good air pollution control practices for minimizing emissions. The general duty to minimize emissions does not require the owner operator to make any further efforts to reduce emissions if levels required by the applicable standard have been achieved. Determination of whether a source is operating in compliance with operation and maintenance requirements will be based on information available to the Administrator, which may include, but is not limited to, monitoring results, review of operation and maintenance procedures, review of operation and maintenance records, and inspection of the source.
- (f) In addition to the cases listed in [§ 63.695(e)(4)](/cfr/40/63.695.md?p=e-4), deviation means any of the cases listed in [paragraphs (f)(1) through (6)](#f-1..f-6) of this section.
  - (1) Any instance in which an affected source subject to this subpart, or an owner or operator of such a source, fails to meet any requirement or obligation established by this subpart, including, but not limited to, any emission limit, operating limit or work practice standard.
  - (2) When a performance test indicates that emissions of a pollutant in Table 1 to this subpart are exceeding the emission standard for the pollutant specified in Table 1 to this subpart.
  - (3) When the average value of a monitored operating parameter, based on the data averaging period for compliance specified in [§ 63.695](/cfr/40/63.695.md), does not meet the operating limit specified in [§ 63.693](/cfr/40/63.693.md).
  - (4) When an affected source discharges directly into the atmosphere from any of the sources specified in paragraphs [(f)(4)(i)](#f-4-i) and [(ii)](#f-4-ii) of this section.
    - (i) A pressure relief device, as defined in [§ 63.681](/cfr/40/63.681.md).
    - (ii) A bypass, as defined in [§ 63.681](/cfr/40/63.681.md).
  - (5) Any instance in which the affected source subject to this subpart, or an owner or operator of such a source, fails to meet any term or condition specified in paragraph [(f)(5)(i)](#f-5-i) or [(ii)](#f-5-ii) of this section.
    - (i) **Any term or condition that is adopted to implement an applicable requirement in this subpart.**
    - (ii) Any term or condition relating to compliance with this subpart that is included in the operating permit for an affected source to obtain such a permit.
  - (6) Any failure to collect required data, except for periods of monitoring system malfunctions, repairs associated with monitoring system malfunctions, and required monitoring system quality assurance or quality control activities (including, as applicable, calibration checks and required zero and span adjustments).

## Notes

### Amendments

[64 FR 38965, July 20, 1999, as amended at 80 FR 14272, Mar. 18, 2015]

### Source

Source: 61 FR 34158, July 1, 1996, unless otherwise noted.

### Authority

Authority: 42 U.S.C. 7401 et seq.

### Source

Source: 57 FR 61992, Dec. 29, 1992, unless otherwise noted.

### Amendments

[64 FR 38965, July 20, 1999, as amended at 80 FR 14272, Mar. 18, 2015]