photoThe U.S. Department of Health and Human Services (HHS) has, after years of prodding, added formaldehyde to its list of known cancer-causing agents, along with a botanical known as aristolochic acids.

Six other substances were added as possible human carcinogens.— captafol, cobalt-tungsten carbide (in powder or hard metal form), certain inhalable glass wool fibers, o-nitrotoluene, riddelliine, and styrene.

The Environmental Protection Agency (EPA) has for years been trying to update its risk assessment for formaldehyde but has been stymied by resistance from the chemical manufacturing industry.

The chemical industry was quick to criticize HHS' decision.

“We are extremely disappointed that HHS has moved forward with listing formaldehyde ... as a ‘known human carcinogen.’ By doing so, HHS ignored the recently released, independent, peer-review report from the National Research Council, which strongly questioned whether the scientific evidence supports the claim of human carcinogen for leukemia. Also, the World Health Organization indicates that normal human exposures do not present a risk of cancer,” said Cal Dooley, President and CEO, American Chemistry Council.

The Report on Carcinogens is a congressionally mandated document that identifies agents, substances, mixtures, or exposures in two categories: known to be a human carcinogen and reasonably anticipated to be a human carcinogen.

A listing in the Report on Carcinogens does not by itself mean that a substance will cause cancer. Many factors, including the amount and duration of exposure, and an individual’s susceptibility to a substance, affect whether a person will develop cancer.

"Reducing exposure to cancer-causing agents is something we all want, and the Report on Carcinogens provides important information on substances that pose a cancer risk," said Linda Birnbaum, Ph.D., director of both the National Institute of Environmental Health Sciences (NIEHS) and the National Toxicology Program (NTP).

The process

Once a substance is nominated by the public or private sector and selected for consideration, it undergoes an extensive evaluation with numerous opportunities for scientific and public input. There were at least six opportunities for public input on each substance, HHS said. The National Toxicology Program (NTP) used established criteria to evaluate the scientific evidence on each candidate substance under review and drew upon the scientific expertise of several federal agencies, including the National Institutes of Health, Centers for Disease Control and Prevention, Agency for Toxic Substances and Disease Registry, U.S. Food and Drug Administration, U.S. Environmental Protection Agency, U.S. Consumer Product Safety Commission, and Occupational Safety and Health Administration, HHS said in a statement.

"The strength of this report lies in the rigorous scientific review process," said Ruth Lunn, Dr.P.H., director of the NTP Office of the Report on Carcinogens. "We could not have completed this report without the significant input we received from the public, industry, academia, and other government agencies."

Formaldehyde

Formaldehyde was first listed in the 2nd Report on Carcinogens as a substance that was reasonably anticipated to be a human carcinogen, after laboratory studies showed it caused nasal cancer in rats.

There is now sufficient evidence from studies in humans to show that individuals with higher measures of exposure to formaldehyde are at increased risk for certain types of rare cancers, including nasopharyngeal (the nasopharnyx is the upper part of the throat behind the nose), sinonasal, as well as a specific cancer of the white blood cells known as myeloid leukemia, HHS said.

Formaldehyde is a colorless, flammable, strong-smelling chemical that is widely used to make resins for household items, such as composite wood products, paper product coatings, plastics, synthetic fibers, and textile finishes. Formaldehyde is also commonly used as a preservative in medical laboratories, mortuaries, and some consumer products, including some hair straightening products.

Aristolochic acids

Aristolochic acids have been shown to cause high rates of bladder or upper urinary tract cancer among individuals with kidney or renal disease who consumed botanical products containing aristolochic acids. Aristolochic acids are a family of acids that occur naturally in some plant species.

Despite a warning issued in 2001 by the U.S. Food and Drug Administration that advised consumers to discontinue use of any botanical products containing aristolochic acids, they can still be purchased on the Internet and abroad, and may be found as a contaminant in herbal products used to treat a variety of symptoms and diseases, such as arthritis, gout, and inflammation.