Gail writes from Pittsburgh, Pennsylvania: "We just had our heating ducts cleaned and were told that two of the returns (one in my bedroom) had insulation in them which they did not feel was supposed to be there. Apparently they vacuumed/cleaned/pulled out the insulation with their vacuum equipment (that lead outside the house). Is there any risk to our family/children in terms of air quality? I woke up with a headache the last two days (although no one else did). Would the process of 'cleaning' stirred up anything? What is insulation? Is it fiberglass?"

Answer: Your duct cleaner was referring to the insulation I am known for advertising - PINK FIBERGLAS™ insulation. Yes, it is fiber glass insulation. Since I cannot see the insulation he removed I am not sure it is ours, but if it is PINK in color it is Owens Corning and it is fiberglass. I am not sure why you would have insulation inside a metal duct, assuming it is a metal duct. In some cases metal ducts are lined with fiberglass duct liner which is typically black in color. Our products can be used in open return-air plenums like you find above many dropped ceilings in commercial buildings.

Owens Corning has conducted extensive fiber sampling research during both installation and use. The level of glass fibers found was 0.04 f/cc of air during installation and 0.0002 f/cc of air after the installation was complete.

Sampling in buildings over many years shows consistently that the materials found in dust are predominantly (a) cellulosic - fibers from newspapers, paper bags, paper boxes; (b) synthetic - fibers from carpets, clothing and furniture; and (c) biological - skin cells, hair follicles, insect parts.

Based on over 60 years of research, Owens Corning believes that its glass fibers are safe to manufacture and use. If you are installing new product, the company recommends that you follow the industry safe work practices to avoid irritation. We would be happy to provide information from Owens Corning, the North American Insulation Manufacturers Association and the American Lung Association with simple information about working safely and avoiding irritation.

In Summary:
- Glass fibers are safe to manufacture, install and use, and
- Installers should follow the industry safe work practices to avoid irritation