Asbestos Millboard Asbestos millboard was used in construction homes all over the world. It became a popular material to use above fireplaces and stove-tops as well as in other locations in walls and ceilings because of its flame-resistant durability. The material reduced fires in homes all over the world. Unfortunately, the asbestos it contained, sometimes comprising up to 80% to 85% of the millboard, put families at risk for developing life-threatening diseases. If the asbestos millboard is intact and not damaged or fraying in any way, the harmful fibers have probably not escaped into the air. Contact a professional who has the proper protective gear, including a face mask and respirator, to remove or dispose of this product. It is possible the millboard could be damaged during the process, releasing the fibers within the material. This can expose residents of the building to possibly inhaling or ingesting these harmful fibers. Though millboard is no longer made with asbestos, substituting substances such as rock wool mineral fibers to provide heat-resistance, many factory and construction workers were exposed to asbestos during the time it was heavily used. Because lung problems often do not surface until many years after the exposure, workers who inhaled any amount of the mineral, large or small, may have a serious disease. Symptoms relating to asbestos may not appear right after one has been exposed to the material. This makes it difficult to treat the disease because most people who develop these symptoms are in the last stages of the illnesses.