Cal. HSC § 80235

(a) “Hazardous material” means a substance or waste that, because of its physical, chemical, or other characteristics, may pose a risk of endangering human health or safety or of degrading the environment. “Hazardous material” includes, but is not limited to, all of the following: (1) A hazardous substance, as defined in Section 25281 or subdivision (a) of Section 78075. (2) A hazardous waste, as defined in Section 25117. (3) A waste, as defined in Section 101075, or as defined in Section 13050 of the Water Code. (4) A substance specified in subdivision (b) of Section 78075. (b) “Hazardous material” does not include undisturbed naturally occurring hazardous material unless it will adversely affect the reasonable use of a property after response action is completed.