The costs for services incurred by the city resulting from a hazardous material release shall include, but shall not necessarily be limited to the following: actual labor costs of city personnel, including all fringe benefit costs, temporary or permanent disability and/or medical expenses; administrative overhead; costs of equipment operation, repair or replacement; costs of material obtained directly by the city; and cost of any contract labor as said costs are required to be expended to mitigate the release of said hazardous materials. (Prior code § 4517)