In the event of spillage or dripping of gasoline, oil, grease, or any other material which may be unsightly or detrimental to the pavement in any area at an air terminal, the same shall be removed immediately. The responsibility for the immediate removal of such gasoline, oil, grease, or other material shall be assumed by the operator of the equipment causing the same or by the tenant or concessionaire responsible for the deposit thereof on the pavement.