Cal. Health and Safety Code § 78505

(a) The director shall notify, within 20 working days, each of the appropriate county health officers as to all the potential abandoned sites of which the department has knowledge or that the department is investigating for releases of hazardous substances that may have occurred or might be occurring at abandoned sites. The county health officers may request quarterly updates on the status of the investigations of these sites. (b) As used in this section, “abandoned site” means an inactive disposal, treatment, or storage facility that cannot, with reasonable effort, be traced to a specific owner, a site whose owner is the subject of an order for relief in bankruptcy, or a location where a hazardous substance has been illegally disposed. (c) Within 10 working days of the identification of an abandoned site, the department or a county health officer shall notify the other agency of the status of the site. The department and the county health officer shall inform the other agency of orders to fence and post these sites and the status of compliance with those orders. The department or the county health officers may request quarterly updates of the testing, enforcement action, and remedial or removal actions that are proposed or ongoing.