Cal. Health & Safety Code § 79235

For purposes of this article, the cost of a removal action includes the cleanup or removal of released hazardous substances from the environment or the taking of other actions that are necessary to prevent, minimize, or mitigate damage that may otherwise result from a release or threatened release, as further defined by Section 101(23) of the federal act (42 U.S.C. Sec. 9601(23)).