Environmental Factor, December 2009, National Institute of Environmental Health Sciences
Expert Panel Recommends Listing Formaldehyde as Known Human Carcinogen
By Robin Mackar
On November 4, a 10-member independent scientific expert panel convened by the National Toxicology Program (NTP) voted unanimously to list formaldehyde as a "known human carcinogen" in the upcoming 12th NTP Report on Carcinogens (RoC). Currently, formaldehyde is listed in the 11th RoC as "reasonably anticipated to be a human carcinogen." The vote came after three days of presentations, public comments and lengthy discussions of the body of literature on this widely used chemical.
"The decision to change the listing status of formaldehyde is based on sufficient evidence in human epidemiology studies, as well as in animal studies, and the fact that a substantial number of U.S. residents are frequently exposed to detectable concentrations of formaldehyde," said Kenneth E. McMartin, Ph.D., chair of the expert panel. McMartin is a member of the Department of Pharmacology, Toxicology and Neuroscience at Louisiana State University Health Sciences Center in Shreveport.
Formaldehyde is a high production chemical with a wide variety of uses. In the United States, formaldehyde is predominantly used to produce industrial resins that are used as adhesives and binders in wood products. It can be found in products such as particle board, glues, permanent press fabrics, paper product coatings, fiberboard and plywood. Formaldehyde is also commonly known for its use as a preservative in medical laboratories and mortuaries.
The panel reviewed numerous key epidemiological studies of workers exposed to formaldehyde in different occupational settings. The studies were deemed sufficient evidence to indicate a causal relationship between exposure to formaldehyde and cancer in humans. Taken together, these human studies revealed three types of cancers, including nasopharyngeal carcinoma, sinonasal adenocarcinoma and myeloid leukemia. "Chance, bias and confounding factors are unlikely to explain the observed excess in these cancers," McMartin noted.
The expert panel noted that in the case of myeloid leukemia, there is evidence of genetic damage in lymphocytes in the blood of formaldehyde-exposed people. These studies and toxicity studies in animals suggest that formaldehyde can produce effects at sites other than the nose and sinus that receive the initial contact of the colorless, strong-smelling gas.
"Having studies linking formaldehyde to not just relatively rare nasal cancers, but to a form of leukemia, which is a more common cancer, is an additional public health concern," said Ruth Lunn, Dr.P.H., director of the Report on Carcinogens Center.
Formaldehyde is one of eight substances under consideration by the NTP for possible listing in the 12th RoC. Next, the NTP will solicit public comment on the expert panel's listing recommendation and scientific justification through the Federal Register, and finalize the background document, taking into consideration the panel's recommended edits and public comments. Following additional internal government review, the NTP will draft its listing recommendation for the 12th RoC and scientific information supporting the recommendation, solicit public comment on the listing recommendation, and convene a meeting of the NTP Board of Scientific Counselors to peer review the science supporting the listing recommendation.
Information about this meeting, and the review of formaldehyde or any other RoC nominated chemical, is available online. (https://ntp.niehs.nih.gov/index.cfm?objectid=03C9AF75-E1BF-FF40-DBA9EC0928DF8B15)
(Robin Mackar is the news director in the NIEHS Office of Communications and Public Liaison and a regular contributor to the Environmental Factor.)