Treated Canvas – Sunforger Flame Retardant This is a 13 oz. army duck that has been treated with a product called Sunforger. It is a water repellent, mildew resistant, and fire retardant which meets CPAI-84 requirements. This canvas is recommended if you live in a high humidity area. Just remember that no canvas is mildew proof! Just mildew resistant, so you must store your canvas goods in a dry place. The fire retardant is not fireproof. Please always use caution.