Cal. Health & Safety Code § 40920.6

(a) Prior to adopting rules or regulations to meet the requirement for best available retrofit control technology pursuant to Sections 40918, 40919, 40920, and 40920.5, or for a feasible measure pursuant to Section 40914, districts shall, in addition to other requirements of this division, do all of the following:
1. (1) Identify one or more potential control options which achieves the emission reduction objectives for the regulation.
2. (2) Review the information developed to assess the cost-effectiveness of the potential control option. For purposes of this paragraph, “cost-effectiveness” means the cost, in dollars, of the potential control option divided by emission reduction potential, in tons, of the potential control option.
3. (3) Calculate the incremental cost-effectiveness for the potential control options identified in paragraph (1). To determine the incremental cost-effectiveness under this paragraph, the district shall calculate the difference in the dollar costs divided by the difference in the emission reduction potentials between each progressively more stringent potential control option as compared to the next less expensive control option.
4. (4) Consider, and review in a public meeting, all of the following:
  1. (A) The effectiveness of the proposed control option in meeting the requirements of this chapter and the requirements adopted by the state board pursuant to subdivision (b) of Section 39610.
  2. (B) The cost-effectiveness of each potential control option as assessed pursuant to paragraph (2).
  3. (C) The incremental cost-effectiveness between the potential control options as calculated pursuant to paragraph (3).
5. (5) Make findings at the public hearing at which the regulation is adopted stating the reasons for the district’s adoption of the proposed control option or options.
(b) A district may establish its own best available retrofit control technology requirement based upon consideration of the factors specified in subdivision (a) and Section 40406 if the requirement complies with subdivision (d) of Section 40001 and is consistent with this chapter, other state law, and federal law, including, but not limited to, the applicable state implementation plan.
(c)
1. (1) On or before January 1, 2019, each district that is a nonattainment area for one or more air pollutants shall adopt an expedited schedule for the implementation of best available retrofit control technology (BARCT), by the earliest feasible date, but in any event not later than December 31, 2023.
2. (2) The schedule shall apply to each industrial source that, as of January 1, 2017, was subject to a market-based compliance mechanism adopted by the state board pursuant to subdivision (c) of Section 38562.
3. (3) The schedule shall give highest priority to those permitted units that have not modified emissions-related permit conditions for the greatest period of time. The schedule shall not apply to an emissions unit that has implemented BARCT due to a permit revision or a new permit issuance since 2007.
(d) Prior to adopting the schedule pursuant to paragraph (1) of subdivision (c), a district shall hold a public meeting and take into account:
1. (1) The local public health and clean air benefits to the surrounding community.
2. (2) The cost-effectiveness of each control option.
3. (3) The air quality and attainment benefits of each control option.
(e) A district shall allow the retirement of marketable emission reduction credits under a program which complies with all of the requirements of Section 39616, or emission reduction credits which meet all of the requirements of state and federal law, including, but not limited to, the requirements that those emission reduction credits be permanent, enforceable, quantifiable, and surplus, in lieu of any requirement for best available retrofit control technology, if the credit also complies with all district rules and regulations affecting those credits.
(f) After a district has established the cost-effectiveness, in a dollar amount, for any rule or regulation adopted pursuant to this section or Section 40406, 40703, 40914, 40918, 40919, 40920, 40920.6, or 40922, the district, consistent with subdivision (d) of Section 40001, shall allow alternative means of producing equivalent emission reductions at an equal or lesser dollar amount per ton reduced, including the use of emission reduction credits, for any stationary source that has a demonstrated compliance cost exceeding that established dollar amount.