WAC 173-401-530   Insignificant emission units.  (1) General. This section contains criteria for identifying insignificant emission units or activities for purposes of the operating permit program. Designation of an emission unit or activity as insignificant for purposes of this chapter does not exempt the unit or activity from any applicable requirement. An emission unit or activity is insignificant based on one or more of the following approaches:

     (a) Actual emissions of all regulated air pollutants from a unit or activity are less than the emission thresholds established in subsection (4) of this section. Such emission units and activities must be listed in the permit application;

     (b) The emission unit or activity is listed in WAC 173-401-532 as categorically exempt. Such emission units or activities do not have to be listed in the permit application;

     (c) The emission unit or activity is listed in WAC 173-401-533 and is considered insignificant if its size or production rate based on maximum rated capacity is below the specified level. These emission units or activities must be listed in the permit application.

     (d) The emission unit or activity generates only fugitive emissions (as defined in WAC 173-400-030(31)), which are subject to no applicable requirement other than generally applicable requirements of the state implementation plan as defined in subsection (2) of this section. These units or activities must be listed on the permit application.

     (2) Applicable requirements.

     (a) Notwithstanding any other provision of this chapter, no emissions unit or activity subject to a federally enforceable applicable requirement (other than generally applicable requirements of the state implementation plan) shall qualify as an insignificant emissions unit or activity. For purposes of this section, generally applicable requirements of the state implementation plan are those federally enforceable requirements that apply universally to all emission units or activities without reference to specific types of emission units or activities.

     (b) The application shall list and the permit shall contain all generally applicable requirements that apply to insignificant emission units or activities in the source.

     (c) Testing, monitoring, recordkeeping and reporting are not required for insignificant emissions units and activities unless determined by the permitting authority to be necessary to assure compliance or unless it is otherwise required by a generally applicable requirement of the state implementation plan. This section does not affect the authority of ecology and local air authorities to establish case-by-case monitoring requirements as set forth in WAC 173-400-105 or other provisions of law.

     (d) Where a permit does not require testing, monitoring, recordkeeping and reporting for insignificant emissions units or activities, the permittee may certify continuous compliance if there were no observed, documented, or known instances of noncompliance during the reporting period. Where a permit requires testing, monitoring, recordkeeping and reporting for insignificant emission units or activities, the permittee may certify continuous compliance when the testing, monitoring, recordkeeping required by the permit revealed no violations during the period, and there were no observed, documented, or known instances of noncompliance during the reporting period.

     (3) Permit shield. The permit shield described in WAC 173-401-640 shall not apply to any insignificant emissions unit or activity designated under this section.

     (4) Insignificant emission thresholds. An emission unit or activity shall be considered insignificant if it qualifies under subsection (1)(b), (c) or (d) of this section, or if its actual emissions, based on methods approved by the permitting authority, are below the practical quantification limit (PQL), or are less than or equal to all of the following threshold levels:

     (a) 5 tons per year of carbon monoxide;

     (b) 2 tons per year of nitrogen oxides;

     (c) 2 tons per year of sulfur oxides;

     (d) 2 tons per year of volatile organic compounds (VOC);

     (e) 0.75 tons per year of PM₁₀ (as defined in WAC 173-400-030);

     (f) 0.005 tons per year of lead;

     (g) 0.15 tons per year of fluorides;

     (h) 0.35 tons per year of sulfuric acid mist;

     (i) 0.5 tons per year of hydrogen sulfide;

     (j) 0.5 tons per year of total reduced sulfur (including hydrogen sulfide);

     (k) 0.000000175 tons per year of municipal waste combustor organics (measured as total tetra- through octa-chlorinated dibenzo-p-dioxins and dibenzofurans);

     (m) 0.75 tons per year of municipal waste combustor metals (measured as PM);

     (n) 2.0 tons per year of municipal waste combustor acid gases (measured as SO₂ and hydrogen chloride);

     (o) 2.0 tons per year of ozone depleting substances in aggregate (the sum of Class I and/or Class II substances as defined in Title VI and 40 CFR Part 82);

     (p) Thresholds levels for hazardous air pollutants as defined in WAC 173-401-531;

     (q) 0.5 tons per year for any regulated air pollutant not listed above or in WAC 173-401-531.

     (5) Documentation.

     (a) Upon request from the permitting authority the applicant must provide sufficient documentation to enable the permitting authority to determine that the emission unit or activity has been appropriately listed as insignificant.

     (b) Upon request from the permitting authority, at any time during the term of the permit, an applicant who lists an activity or emissions unit as insignificant under subsection (1)(a) of this section shall demonstrate to the permitting authority that the actual emissions of the unit or activity are below the emission thresholds listed in subsection (4) of this section.

     (6) Permit revision.

     If an emission unit or activity that qualifies as insignificant solely on the basis of subsection (1)(a) of this section exceeds one of the emissions thresholds specified in subsection (4) of this section prior to issuance of a permit, the applicant shall promptly amend its permit application to include the relevant activity or emissions unit in the permit, as provided in WAC 173-401-500(6). Once the permit is issued, an activity or emissions unit that qualifies as insignificant solely on the basis of subsection (1)(a) of this section shall not exceed the emissions thresholds specified in subsection (4) of this section, until the permit is modified pursuant to WAC 173-401-725 (Permit modifications).

     (7) Local air authority discretion. Local air authorities may establish by rule other criteria for defining insignificant emissions units or activities. At a minimum, such criteria must be at least as stringent as the requirements in subsections (2) and (3) of this section. Insignificant emission units or activities defined by local air authority rule may not exceed threshold levels established under subsection (4) of this section.



[Statutory Authority: RCW 70.94.161(2). 02-19-078 (Order 02-02), § 173-401-530, filed 9/16/02, effective 10/17/02. Statutory Authority: Chapter 70.94 RCW. 94-11-105 (Order 93-30), § 173-401-530, filed 5/17/94, effective 6/17/94.]