Heating units that contain heating ducts that help control the temperature of spaces where children and adults learn, play, and teach are found in nearly all large buildings. Heating ducts are corridors that are narrow and pipe-like. They provide hot air, cool air, and filtered air to the rooms inside these buildings. The materials, both conductive and insulating, make these heating ducts efficient and effective, and maintain comfortable temperatures throughout the building.
Prior to the 1980s, asbestos was the material of choice in the making of many heating ducts. It is flame resistant and a poor conductor of heat, which made it seem to be the perfect choice. During the 1980s, the public was finally made aware of the serious health issues connected to asbestos.
Decades before the public was made aware of the dangers of asbestos exposure, science had already proven that asbestos was the cause of several serious illnesses like lung cancer, heart disease, asbestosis, and mesothelioma. However, by the time this became widely known, it was too late for many of those who were already developing the signs of one of these conditions.