Abstract: An apparatus for vaporizing a chemical agent and delivering the chemical agent as a fumigant to an area requiring treatment is disclosed. The vaporizing apparatus includes a heater in fluid communication with a gas stream. A mixer 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 mixer whereby the hot gas stream contacts the chemical agent stream, vaporizing at least part of the chemical agent stream. A method of treatment using the apparatus is also disclosed.