HHS Names 8 New Carcinogens to Avoid

Ingredients in styrofoam, herbal supplements, and other consumer goods were among the agents added to the US government's list of potential cancer risks.

Ingredients in styrofoam, herbal supplements, and other consumer goods were among the agents added to the US government's list of potential cancer risks.

Formaldehyde, an embalming agent that is also present in some personal care products, along with styrene, a compound found in the ubiquitous disposable food containers, were among the 8 substances added to the US Department of Health and Human Services’ (HHS) list of known and suspected cancer-causing agents, federal officials announced Friday.

The inclusion of formaldehyde may prompt questions from patients, since it is an ingredient in hair straighteners, nail polish, and other cosmetics that can be purchased on pharmacy shelves. In its updated “Report on Carcinogens,” HHS also warned of aristolochic acids and riddelliine—ingredients that are present in certain herbal medicines and other plant-derived remedies.

The report is compiled by the National Institute of Environmental Health Sciences (NIEHS) and the National Toxicology Program (NTP), and is based on in-depth reviews of available scientific evidence.

The Centers for Disease Control and Prevention, National Institutes of Health, FDA, Environmental Protection Agency, US Consumer Product Safety Commission, and the Occupational Safety and Health Administration each played a role in evaluating candidates for the list, which includes both known carcinogens and “reasonably anticipated” carcinogens.

“The strength of this report lies in the rigorous scientific review process,” said Ruth Lunn, DrPH, director of the NTP office.

Limiting exposure

Past studies have linked riddelliine to liver cancer and leukemia in rats and mice, and the toxic botanical has been detected in meat, milk, and honey, as well as some herbal medicines and teas. Humans can also be exposed by eating foods from animals that consumed plants of the Senecio species, a natural source of riddelliine that grows in the western United States.

Aristolochic acids, like riddelliine, occur naturally in some plant species, and are associated in human trials with a higher risk of bladder cancer and cancer of the upper urinary tract. The ingredient was flagged by the FDA in 2001, but can be still found in natural products marketed online and abroad for the treatment of inflammation, gout, and arthritis. Rheumixx, a treatment for muscle and joint relief, and BioSlim Doctor’s Natural Weight Loss System Slim Tone Formula both contain the carcinogenic, according to the FDA.

Also present in pharmaceuticals is a substance called o-Nitrotoluene, which has been tied to tumor formation at multiple tissue sites in studies involving animals. The newest additions to the official 240-item carcinogens list include:


Aristolochic acids






Cobalt-tungsten carbide


Inhalable glass wool fibers







Aristolochic acids and formaldehyde are the only substances that meet NTP's criteria for "known carcinogens"; the remaining 6 products are considered "reasonably anticipated" carcinogens. Limiting human exposure to all of these agents is a primary goal of the report, according to Linda Birnbaum, PhD, NIEHS and NTP director.

“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. The NTP is pleased to be abe to compile this report,” she said.

For more information about oncology and specialty pharmaceuticals, visit the May 2011 Oncology Issue of Specialty Pharmacy Times.

For other articles in this issue, see:

  • Sticking to a Statin Regimen Pays Off
  • Preventing Preterm Births with a Flu Shot
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