Controlled release ampule containing a fumigant

A wooden structure which is protected from decay for a prolonged period of time by controlled, prolonged treatment with a fumigant, said structure comprising:

• a wooden structure;
• and
• a fumigant which is contained within at least one sealed container inserted into said wooden structure,
• wherein said fumigant is selected from the group consisting of
• chloropicrin, methyl isothiocyanate, sodium N-methyl-dithiocarbamate, cis-(N-(1, 1,2,2-tetrachloroethyl)thio)-4-cyclohexene-1,2-dicarboximide, aluminum phosphide, and combinations thereof, said container having walls which are comprised of a fiber free heat sealable organic polymer, wherein said organic polymer is selected from the group consisting of high density polyethylene, low density polyethylene, high density polypropylene, polyvinylidene fluoride, surface fluorinated high density polyethylene and combinations thereof, which container is a single or multiple layer tube sealed at one end by heat and at the other end by a screw cap, which polymer is permeable to but otherwise inert to said fumigant, said walls allowing said fumigant to be retained for a period of time of at least one year or for increasing periods of one year up to about 30 years while permitting controlled release of a sufficient amount of said fumigant to diffuse at a rate of fumigant loss of between about 1 and 15 mg/day through said walls to protect said wooden structure from decay for a period of time of at least 1 year or for increasing periods of one year up to about 30 years, with the proviso that no external force other than ambient pressure and temperature is present to release said fumigant from said sealed container, with the proviso that said container does not have an opening which is sealed with a material which degrades within a certain time to create the opening from which the fumigant leaves the container.