Cal. Public Resources Code § 45012

(a) If an enforcement agency, despite having made a good faith effort pursuant to its enforcement authority or any other authority, is unable to correct a violation, and the board, acting through its executive director, and the enforcement agency both agree that enforcement by the board is feasible and desirable pursuant to these circumstances, the board, acting through its executive director, may take any appropriate enforcement action pursuant to this section. (b) (1) Notwithstanding subdivision (a), the board shall not take any enforcement action specified in this part without providing notice to the enforcement agency and the violator of the board’s intent to take that action, allowing the enforcement agency and the violator a reasonable opportunity to correct the violation, and conducting a public hearing on the matter. (2) When taking an enforcement action pursuant to this section, the board is vested, in addition to its other powers, with all of the authority to take an action that an enforcement agency may take pursuant to this division. (c) Notwithstanding subdivisions (a) and (b), if the board finds that an enforcement agency’s failure to take enforcement action constitutes an imminent threat to public health and safety or to the environment, the board may take the enforcement action that the board determines is necessary.