California Code, Health and Safety Code - HSC § 79590

(a)(1) The department may issue a complaint to any person subject to a penalty pursuant to Sections 78680 and 79550.

(2) The complaint shall allege the acts or failures to act that constitute a basis for liability and the amount of the proposed penalty.

(3) The complaint shall be served by personal service or certified mail and shall inform the party so served of the right to a hearing.

(b)(1) Any person served with a complaint pursuant to this section may, within 45 days after service of the complaint, request a hearing by filing a notice of defense with the department. A notice of defense is deemed to be filed within a 45-day period if it is postmarked within the 45-day period.

(2) If no notice of defense is filed within 45 days after service of the complaint, the department shall issue an order setting liability in the amount proposed in the complaint, unless the department and the party have entered into a settlement agreement, in which case the department shall issue an order setting liability in the amount specified in the settlement agreement.

(3) Where the party has not filed a notice of defense or where the department and the party have entered into a settlement agreement, the order shall not be subject to review by any court or agency.