ThomsonHoover Welcome to Hoover Treated Wood Products, the largest producer of fire retardant treated wood in the world. Pyro-Guard and Exterior Fire-X fire retardant lumber and plywood are UL listed and have been issued an ESR confirming Code Compliance with the Building Codes. With a nationwide network of stocking distributors, our fire retardant products are readily available. Insist on Hoover?s UL listed, labeled, and kiln dried fire retardant lumber and plywood for your next purchase. Hoover Treated Wood Products offers a full line of pressure treating services for lumber and plywood, inc