California Code, Public Resources Code - PRC § 21086

(a) A public agency may, at any time, request the addition or deletion of a class of projects, to the list designated pursuant to Section 21084.  That request shall be made in writing to the Office of Planning and Research and shall include information supporting the public agency's position that the class of projects does, or does not, have a significant effect on the environment.

(b) The Office of Planning and Research shall review each request and, as soon as possible, shall submit its recommendation to the Secretary of the Resources Agency.  Following the receipt of that recommendation, the Secretary of the Resources Agency may add or delete the class of projects to the list of classes of projects designated pursuant to Section 21084that are exempt from the requirements of this division.

(c) The addition or deletion of a class of projects, as provided in this section, to the list specified in Section 21084 shall constitute an amendment to the guidelines adopted pursuant to Section 21083 and shall be adopted in the manner prescribed in Sections 21083and21084.