Cal. Health & Safety Code § 25296.25

(a)
1. (1) Unless the board, in consultation with local agencies and the regional board, determines that a site is an emergency site, the board, at the request of a responsible party who is eligible for reimbursement of corrective action costs under Chapter 6.75 (commencing with Section 25299.10), may suspend additional corrective action or investigation work at a site, based on a preliminary site assessment conducted in accordance with the corrective action regulations adopted by the board, but the board shall not suspend any of the following activities pursuant to this section:
  1. (A) Removal of, or approved modifications of, existing tanks.
  2. (B) Excavation of petroleum saturated soil or removal of excess petroleum from saturated soil.
  3. (C) Removal of free product from the saturated and unsaturated zones.
  4. (D) Periodic monitoring to ensure that released petroleum is not migrating in an uncontrolled manner that will cause the site to become an emergency site.
2. (2) For purposes of this subdivision, “emergency site” means a site that, because of an unauthorized release of petroleum, meets one of the following conditions:
  1. (A) The site presents an imminent threat to public health or safety or the environment.
  2. (B) The site poses a substantial probability of causing a condition of contamination or nuisance, as defined in Section 13050 of the Water Code, or of causing pollution of a source of drinking water at a level that is a violation of a primary or secondary drinking water standard adopted by the State Department of Health Services pursuant to Chapter 4 (commencing with Section 116270) of Part 12 of Division 104.
(b) The suspension shall continue until one of the following occurs:
1. (1) The board provides the eligible responsible party with a letter of commitment pursuant to Chapter 6.75 (commencing with Section 25299.10) that the party will receive reimbursement for the corrective action.
2. (2) The responsible party requests in writing that the suspension be terminated and that the work continue.
3. (3) The fund established pursuant to Article 6 (commencing with Section 25299.50) of Chapter 6.75 is no longer in existence.
(c) The board shall adopt regulations pursuant to Section 25299.3 that specify the conditions under which a site is an imminent threat to public health or safety or to the environment or poses a substantial probability of causing a condition of contamination, nuisance, or pollution as specified in paragraph (2) of subdivision (a). The board shall not suspend corrective action or investigation work at any site pursuant to this section until the effective date of the regulations adopted by the board pursuant to this subdivision.