California Code, Health and Safety Code - HSC § 42372

(a) The hearing board, in making any order permitting a product variance, shall specify the time during which the order shall be effective, which, except as provided in subdivision (b), shall not exceed one year, and shall set a final compliance date.

(b) A product variance may be issued for a period exceeding one year, but in no event to exceed two years from the date of the granting of the initial product variance, if the product variance includes a schedule of increments of progress specifying a final compliance date by which the emission of air contaminants from the product for which the product variance is granted will be brought into compliance with applicable emission standards and all district rules, regulations, and orders. No extension may be granted to a petitioner without a showing of good cause and proof of compliance with the findings required by Section 42368.

(c) If the product variance is for a process or product that is equivalent to, or exceeds, the applicable standards required by the district's rules and regulations, and the hearing board granting the variance specifies that the only way to achieve compliance will be for the district to adopt or amend a rule or regulation, the air pollution control officer within 180 days from the effective date of the variance, shall set a public hearing before the district governing board and make a recommendation on whether or not the board should adopt or amend a rule or regulation to bring the product into compliance. The district governing board shall, within one year of the effective date of the variance, take action to (1) adopt or amend a district rule or regulation to bring the product into compliance, or (2) determine that no amendment, rule, or regulation is warranted. If the district governing board fails to take either action, nothing in this subdivision shall limit the petitioner's rights and remedies under existing law.