An apparatus for vaporising a chemical agent and delivering the chemical agent as a fumigant to an area requiring treatment is disclosed. The vaporising apparatus comprises a heater in fluid communication with a gas stream. A mixing means is in fluid communication with a chemical agent stream. The heater heats gas to produce a hot gas stream. The hot gas stream is directed to the mixing means whereby the hot gas stream contacts the chemical agent stream, vaporising at least part of the chemical agent stream. A method of treatment using the apparatus is also disclosed.
