North American composites, including laminated veneer lumber, oriented strandboard, and medium density fiberboard, were treated by vapor boron technology and subsequently tested in static bending. Tensile properties were also determined for the two composite board products. The study was designed as a 2 x 3 factorial with two mill locations and three treatment levels for each composite type. In general, mill location significantly affected most property values, while treatment level caused only significant reductions at the highest treatment level. The significance of mill location was attributed mainly to species differences since species varied between locations for each composite type