340-224-0025

Major Modification

(1) Except as provided in section (5), "major modification" means a change at a source described in section (2) or (3) for any regulated pollutant subject to NSR since the later of:

(a) The baseline period for all regulated pollutants except PM2.5;

(b) May 1, 2011 for PM2.5; or

(c) The most recent NSR permitting action for that regulated pollutant that changed the netting basis under OAR 340-222-0046(3)(e).

(2)(a) Any physical change or change in the method of operation of a source that results in emissions described in paragraphs (A) and (B):

(A) A PSEL or actual emissions that exceed the netting basis by an amount that is equal to or greater than the SER; and

(B) The accumulation of emission increases due to physical changes and changes in the method of operation that is equal to or greater than the SER. For purposes of this paragraph, emission increases shall be calculated as follows: For each unit with a physical change or change in the method of operation occurring at the source since the later of the dates in subsections (1)(a) through (1)(c) as applicable for each pollutant, subtract the unit’s portion of the netting basis from its post-change potential to emit taking into consideration any federally enforceable limits on potential to emit. Emissions from categorically insignificant activities, aggregate insignificant emissions, and fugitive emissions must be included in the calculations.

(b) For purposes of this section:

(A) Emission increases due solely to increased use of equipment or facilities that existed or were permitted or approved to construct in accordance with OAR 340 division 210 during the applicable baseline period are not included, except if the increased use is to support a physical change or change in the method of operation.

(B) If a portion of the netting basis or PSEL or both was set based on PTE because the source had not begun normal operations but was permitted or approved to construct and operate, that portion of the netting basis or PSEL or both must be excluded until the netting basis is reset as specified in OAR 340-222-0046(3)(d) and 340-222-0051(3).

(3) Any change at a source, including production increases, that would result in a PSEL increase of 1 ton or more for any regulated pollutant for which the source is a major source in nonattainment, reattainment, or maintenance areas or a federal major source in attainment, unclassified or sustainment areas, if the source obtained permits to construct and operate after the applicable baseline period but has not undergone Major NSR or Type A State NSR action under OAR 340 division 224.

(a) This section does not apply to PM2.5 and greenhouse gases.

(b) Changes to the PSEL solely due to the availability of more accurate and reliable emissions information are exempt from being considered an increase under this section.

(4) Major modifications for ozone precursors or PM2.5 precursors also constitute major modifications for ozone and PM2.5, respectively.

(5) The following are not major modifications:

(a) Except as provided in section (3), increases in hours of operation or production rates that would cause emission increases above the levels allowed in a permit but would not involve a physical change or change in method of operation of the source.

(b) Routine maintenance, repair, and replacement of components.

(c) Temporary equipment installed for maintenance of the permanent equipment if the temporary equipment is in place for less than six months and operated within the permanent equipment's existing PSEL.

(d) Use of alternate fuel or raw materials, that were available during, and that the source would have been capable of accommodating in the baseline period.

(6) When more accurate or reliable emissions information becomes available, a recalculation of the PSEL, netting basis, and increases/decreases in emissions must be performed to determine whether a major modification has occurred.

[ED. NOTE: This rule was moved verbatim from OAR 340-200-0020(71) and amended in redline/strikeout. See history under OAR 340-200-0020.]

NOTE: This rule is included in the State of Oregon Clean Air Act Implementation Plan as adopted by the EQC under OAR 340-200-0040.

Stat. Auth.: ORS 468.020, 468A.025, 468A.035, 468A.055 & 468A.070
Stats. Implemented: ORS 468A.025 & 468A.035