Cal. Health & Safety Code § 120176

During an outbreak of communicable disease, or upon the imminent and proximate threat of communicable disease outbreak or epidemic that threatens the public’s health, all health care providers, clinics, health care service plans, pharmacies, their suppliers, distributors, and other for-profit and nonprofit entities shall, upon request of the local health officer, disclose to the local health officer inventories of, critical medical supplies, equipment, pharmaceuticals, vaccines, or other products that may be used for the prevention of, or may be implicated in the transmission of communicable disease. The local health officer shall keep this proprietary information confidential.