California Code, Health and Safety Code - HSC § 25359.7

(a) Any owner of nonresidential real property who knows, or has reasonable cause to believe, that any release of hazardous substance has come to be located on or beneath that real property shall, prior to the sale, lease, or rental of the real property by that owner, give written notice of that condition to the buyer, lessee, or renter of the real property. Failure of the owner to provide written notice when required by this subdivision to the buyer, lessee, or renter shall subject the owner to actual damages and any other remedies provided by law. In addition, where the owner has actual knowledge of the presence of any release of a material amount of a hazardous substance and knowingly and willfully fails to provide written notice to the buyer, lessee, or renter, as required by this subdivision, the owner is liable for a civil penalty not to exceed five thousand dollars ($5,000) for each separate violation.

(b) Any lessee or renter of real property who knows or has reasonable cause to believe that any release of a hazardous substance has come or will come to be located on or beneath that real property shall, within a reasonable period of time, either prior to the release or following the discovery by the lessee or renter of the presence or believed presence of the hazardous substance release, give written notice of that condition to the owner of the real property or to the lessor under the lessee's or renter's lease or rental agreement.