In October of 2001, the International Agency for Research on Cancer (IARC) changed the classification of “insulation glass wool” from Group 2B (possibly carcinogenic) to Group 3 (not classifiable as to its carcinogenicity to humans).
On June , 2011, the National Toxicology Program (NTP) removed from its list of “Reasonably Anticipated To Be Carcinogens” biosoluble glass wool fibers. This change means that a cancer warning label for biosoluble fiberglass home and commercial insulation is no longer required under federal law.
Biosoluble fiber is one that dissolves readily in the lungs, as opposed to biopersistent fibers, which remain in the lungs for a much longer time. Biopersistent fibers are not used for insulation.
NAIMA, the North American Insulation Manufacturers Association, has, since the 1930s, asserted that biosoluble fibers are safe to manufacture, install, and use, when the proper procedures are followed.