Formaldehyde linked to various cancers
The National Cancer Institute (NCI) recently released updated results of a study that has followed over 25,000 workers since the 1980s. The report, which will appear May 20 in the Journal of the National Cancer Institute, found that workers employed at plants that used or produced formaldehyde had an increased risk of dying from blood and lymphatic cancers. In fact, those with the greatest exposure to formaldehyde had a 37% increased risk of death from such cancers compared to those with the least exposure. What’s more, those with the greatest levels of exposure were 78% more likely to die from myeloid leukemia, a cancer of the white blood cells.
Although the NCI and the Environmental Protection Agency hesitate to call these results conclusive regarding a causative link between formaldehyde and various cancers, in June 2004, after evaluating all data then existing, the International Agency for Research on Cancer (IARC) classified formaldehyde as a known human carcinogen. It had been classified by the IARC as a probably human carcinogen since 1995.
According to a 1997 report by the U.S. Consumer Product Safety Commission, formaldehyde is normally present in both indoor and outdoor air at low levels—usually less than 0.03 parts of formaldehyde per million parts of air (ppm). However, materials containing formaldehyde can release
formaldehyde gas or vapor into the air, and the home is—well, home to many products that emit formaldehyde.
According to NCI, during the 1970s, urea-formaldehyde foam insulation (UFFI) was used in many homes. However, the NCI’s website states that few homes are now insulated with UFFI and that homes in which UFFI was installed many years ago are not likely to have high formaldehyde levels at this time. Pressed-wood products containing formaldehyde resins are, however, often a significant source of formaldehyde in homes. Of these, urea-formaldehyde (UF) resins are the most toxic.
Formaldehyde is also used to add a permanent press to clothing and draperies, as a component of glues and adhesives, and as a preservative in some paints and coating products. Still, in homes, the most significant sources of formaldehyde are likely to be pressed-wood products made using adhesives that contain UF resins. Pressed-wood products made for indoor use include:
- particleboard (used as sub-flooring and shelving and in cabinetry and furniture);
- hardwood plywood paneling (used for decorative wall coverings as well as in cabinets and furniture);
- medium-density fiberboard (used for drawer fronts, cabinets, and furniture tops).
Medium-density fiberboard contains a higher resin-to-wood ratio than any other UF pressed-wood product and is generally recognized as being the highest formaldehyde-emitting pressed-wood product used in the home.
In releasing the evidence of a link between cancer and formaldehyde, NCI essentially reversed the position it took in 1986 when it said, after a four-year study, that there was little evidence that formaldehyde contributed to cancer. A New York Times article from March 3, 1986 quotes an NCI report as saying that the data back then “‘provide little evidence that mortality from cancer is associated with formaldehyde exposure at levels experienced by workers in this study.”
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