Halon is being removed from all Esso facilities in accordance with Victorian Environment Protection Legislation for the control of ozone depleting substances. The phasing out of halon as a fire protection system required critical evaluation of available alternatives for protection of turbine machinery and switchgear rooms.Esso Australia Ltd., having evaluated and tested a range of available halon replacement systems, has selected a European manufactured water mist as the preferred alternative for fire protection of turbine machinery enclosures. The system selected required significant modifications from the vendor's standard configuration in order for it to be applied to the offshore environment, be accepted by turbine Original Equipment Manufacturers and achieve independent third party certification. Water mist cannot be applied in all situations to replace halon, with an inert gaseous agent required for the protection of switchgear rooms and for flare snuffing.This paper discusses the issues associated with the selection and installation of this new technology and the lessons learnt. It also discusses issues associated with the evaluation, testing, design and installation of over 80 systems on 14 offshore platforms and two onshore plants.