The present invention provides an apparatus and method for controlled release of a fumigant into a wooden structure to prevent decay of that structure. According to the present invention, a fumigant in an ampule or container is inserted into the wooden structure. The ampule or container is made of a polymeric material that does not react with the fumigant, but having walls which are permeable to the fumigant such that, when inserted into the wooden structure, the rate of release of the fumigant through the walls of the ampule is slow enough to continuously treat and arrest decay of the wooden structure, particularly decay caused by fungi, over extended periods of time (i.e., 1, 5, 7, 10, 15, 20 or 30 years). The rate of release of the fumigant can be controlled by the type of fumigant, the shape of the container, the specific polymer used to make the container, and by the thickness of the container wall.
William W. Harlowe Jr.; William A. McMahon; Donald J. Mangold; Bruce Bernstein