California Code, Public Resources Code - PRC § 43606

(a) Except for financial arrangements approved by the board pursuant to this article, no indemnification, hold harmless, or similar agreement or conveyance is effective to transfer from the owner or operator of a disposal site to any other person any obligations imposed on the owner or operator under this article.

(b) Notwithstanding subdivision (a), nothing in this section prohibits any agreement between the owner and the operator regarding their respective obligations for closure and postclosure maintenance of a disposal site, and nothing in this section prohibits a cause of action that an owner or operator has or would have against the other party by reason of that agreement.