Polk County Insulation > Home Insulation Blog > Debunking the Myths of Fiberglass Insulation and Cancer

Fiberglass InsulationFiberglass insulation carries with it some pretty strong myths about its dangers, the most common being that it causes cancer. Research and science has advanced through the years to be able to better qualify these statements. The use of fiberglass insulation has been popular since around the 1930s, and at that point, while its conductivity properties were well known, its dangers were not. It wasn’t until 1987, however, that these vitreous fibers were identified as carcinogens by the International Agency for Research on Cancer (IARC). Because of this identification, some governmental agencies adopted the idea that fiberglass insulation was cancer-causing because of the possible link to these carcinogens. Both domestic and international groups began researching the properties of the fiberglass in fiberglass insulation. Because of some of this more in-depth research and its findings, in 2001 the IARC moved the classification of these fiberglass fibers from “possibly carcinogenic” (Group 2B) to “not classifiable as to its carcinogenicity to humans” (Group 3).


In 2011, the National Toxicology Program released its findings saying that not all glass wool fibers cause cancer, allowing for residential, commercial and industrial insulation to no longer have the cancer label on their packaging. They found that only certain, very durable fibers can enter the respiratory system and remain in the lungs long term. California even modified its law, which required that signs be posted about the carcinogenic properties in the building except for inhalable and bio persistent glass wool fibers. If you’ve ever been to California, these signs and labels are in the majority of buildings and restaurants throughout the state, for a number of different factors, so qualifying the fiberglass insulation is a big step. While the complete dangers or risks of fiberglass insulation are not fully known (skin rashes or irritants), the previous thought that using it in your home caused cancer, has been successfully refuted today. All current research shows that the correlation is minimal at best.