Cal. Health and Safety Code § 25395.93

(a) A person may withdraw from an agreement entered into pursuant to this article by providing a 30-day written notice to the agency and doing both of the following: (1) Reimbursing the agency for all costs incurred by the agency pursuant to the agreement. (2) Demonstrating to the satisfaction of the agency that conditions at the site to which the agreement applies do not pose an endangerment to public health and safety or the environment. If the agency determines that conditions at the site pose an endangerment to public health, safety, or the environment, this article does not prevent the agency from exercising its authority to take appropriate response actions or to cause the person or persons responsible for the endangerment to take appropriate response actions. (b) A person who enters into an agreement with an agency pursuant to this article shall reimburse the agency for all agency costs, including, but not limited to, costs incurred while reviewing a site assessment plan or a response plan or overseeing the implementation of a site assessment or response plan by the person pursuant to this article, except that the department’s costs shall be reimbursed pursuant to Chapter 6.66 (commencing with Section 25269) and shall be recoverable pursuant to Section 79650. (c) The entry into an agreement pursuant to this article shall not constitute an admission of fact or liability or conclusion of law for any purpose or proceeding and a person who enters into an agreement under this article shall not be deemed liable under any other provision of law solely by reason of entering into that agreement. (d) If the conditions described in paragraph (1) of subdivision (c) of Section 25395.81 or in subdivision (d) of Section 25395.81 occur, an agency may withdraw from an agreement entered into pursuant to this chapter by providing a 30-day written notice to the other party.