(a) An ERC may be used in a net emission increase determination, internal offset, or as an emission offset.

(b) An ERC may be used as an internal offset or emission offset, as applicable, without time limit or restriction within New York State. In another state in the ozone transport region, an ERC may be used as an emission offset in accordance with that state's requirements if New York State has established a reciprocal trading agreement with that state.

(c) An ERC, to be used for purposes of netting, must be the same regulated NSR contaminant as the emission increase requiring the ERC.

(d) An ERC, to be used as an offset, must be the same regulated NSR contaminant as the emission increase requiring the ERC, unless a precursor is allowed under sections 231-5.5 or 231-6.6 of this Part.

(e) In areas where NO_x is a regulated precursor for ozone and PM-2.5, NO_x offsets that occurred on or after April 5, 2005 and meet all applicable location requirements can be used to offset NO_x emissions in both ozone and PM-2.5 nonattainment areas, with the amount of offsets required determined by the higher of the applicable offset ratios.

(f) An ERC may include emission reductions from control or elimination of fugitive emissions, provided these emissions are contained in the New York State emissions inventory.

(g) An ERC, or portion thereof, which was used to avoid a determination of a significant net emission increase, as an internal offset, or as an emission offset cannot subsequently be used for demonstrating attainment with ambient air quality standards or reasonable further progress in a federally approved SIP.

(h) An ERC, or portion thereof, which was used to avoid a determination of a significant net emission increase, cannot subsequently be used as an internal offset, emission offset, or in any subsequent netting determinations.

(i) An ERC, or portion thereof, which was used as an internal offset or an emission offset cannot be used again for any purpose.

(j) An ERC of NO_x, PM-10, or VOC used as an emission offset or for netting, for compliance with Subpart 231-5 or 231- 6 of this Part, must have physically occurred on or after November 15, 1990.

(k) An ERC of PM-2.5 or SO₂ used as an emission offset or for netting, for compliance with Subpart 231-5 or 231- 6 of this Part, must have physically occurred on or after April 5, 2005.

(l) An ERC used as an internal offset for NO_x or VOC emissions must have physically occurred on or after November 15, 1990 but need not be contemporaneous.

(m) The department will approve applications for ERCs submitted on or after the effective date of this regulation on an emission source basis. Applications submitted prior to the effective date of this regulation will be processed according to the provisions of Subpart 231-2 of this Part.

(n) ERCs may be created from past or future emission reductions resulting from facility shutdown, emission source shutdown, curtailment, emission source reduction, over control of emissions beyond an applicable limit, or any other reduction mechanism acceptable to the department.

(o) The department may approve future emission reductions only if they are designated for a specific facility. The facility seeking to establish the future emission reductions must submit an application to the department for modification of its Part 201 permit. The permit of the facility proposing to use the future emission reductions must identify the source(s) of the reductions. The permit of the facility establishing the future emission reductions is subject to modification by the department to remove the approval of the future emission reductions if the facility proposing to use the future emission reductions does not commence construction within the time period specified in this Part, or if the applicant notifies the department of its intent to abandon the proposed new or modified facility and the applicant surrenders the permit prior to commencement of operation.

(p) Emission reductions resulting from the shutdown of an unpermitted emission source which was subject to the requirement to obtain a permit pursuant to Part 201 of this Title will not be certified as ERCs.

(q) Unpermitted emission sources that are operational may be considered for ERCs in accordance with this Part subsequent to being permitted in accordance with Part 201 of this Title.