Description: Officials from the Borough of Hackney's Public Health Department demonstrate the decontamination of clothing both by the use of hot air currents in gas fumigation chambers and via the use of disinfecting machines. Sand and bromide are used to show the persistency of some gases. An official climbs through a frame which has a curtain at each end, demonstrating how an airlock is used to prevent the entrance of poisonous gases. Officials decontaminate and clean their equipment. The undressing procedure is shown. The treatment of grassland contaminated by mustard gas is demonstrated. The final shots show the filling in of a bomb hole and the decontamination of the surrounding ground and vegetation.