While performing the necessary work on private properties referred to in §
256-24 above, the Board of Selectmen or duly authorized representative of the town shall observe all safety rules applicable to the premises established by the owner, and the owner shall be held harmless for injury or death to the town representative, and the town shall indemnify the owner against loss or damage to its property by the town representative and against liability claims and demands for personal injury or property damage asserted against the owner and growing out of the gauging and sampling operation, except as such may be caused by negligence or failure of the owner to maintain safe conditions as required in Article
III, §
256-20.