1. (b) Use of a NO_x or VOC ERC as part of an internal offset. An ERC shall meet the following conditions to be used as part of an internal offset:

   1. (1) an ERC shall come from an emission source within the same existing major facility as a proposed NSR major modification;
   2. (2) an ERC shall have physically occurred on or after November 15, 1990, but need not be contemporaneous with a proposed NSR major modification for which the reduction is used; and
   3. (3) an ERC, or portion thereof, shall be included as a condition in the permit for the proposed NSR major modification for which the reduction is used.

This section represents a mechanism for avoiding a determination of applicability of this Part, for emissions of VOC or NO_x in the severe ozone nonattainment area only, in those instances where a NSR major modification is proposed at an existing major facility and a net emission increase determination of non-applicability is not possible.

(a) Internal offset applicability.

An internal offset shall be considered for purposes of determining applicability or degree of control required under section 231-6.1(d)(1) or (2) of this Subpart for a proposed NSR major modification.