California Code, Public Resources Code - PRC § 42846

(a) The board may expend available moneys to perform any cleanup, abatement, or remedial work required under the circumstances set forth in Section 42845 which in its judgment is required by the magnitude of endeavor or the need for prompt action to prevent substantial pollution, nuisance, or injury to the public health or safety.  The action may be taken in default of, or in addition to, remedial work by the violator or other persons, and regardless of whether injunctive relief is being sought.

(b) The board may perform the work itself, or by or in cooperation with any other governmental agency, and may use rented tools or equipment, either with operators furnished or unoperated.  Notwithstanding any other provisions of law, the board may enter into oral contracts for that work, and the contracts, whether written or oral, may include provisions for equipment rental and in addition the furnishing of labor and materials necessary to accomplish the work.  The contracts are exempt from approval by the Department of General Services pursuant to Section 10295 of the Public Contract Code.