Cal. Public Resources Code § 3744

(a) Within 30 days from the date of service of an order made pursuant to Section 3743, or if there has been an appeal from the order to the director, within 30 days after service of the decision of the director, or if a review has been taken of the order of the director, within 10 days after the affirmance of the order, the operator shall commence in good faith the work ordered and continue it until completion. If the work has not been commenced and continued to completion, the supervisor may appoint necessary agents to enter the premises and perform the work. An accurate account of the expenditures shall be kept. Any amount so expended constitutes a lien against the real or personal property of the operator upon which the work is done and the lien has the force, effect, and priority of a judgment lien pursuant to Section 3772. (b) Notwithstanding Section 3741, 3743, or 3755, if the supervisor determines that an emergency exists, the supervisor may make formal or emergency orders or undertake any other action that the supervisor determines to be necessary for the protection of life, health, property, or natural resources.