The US Department of Health and Human Services (HHS) has added eight substances to its 12th Report on Carcinogens, bringing the number of entries on the list to 240.  

The congressionally mandated document, which is prepared by the National Toxicology Program, identifies agents, substances, mixtures, or exposures in two categories: known to be a human carcinogen and reasonably anticipated to be a human carcinogen. Being listed in the Report of Carcinogens ( does not by itself mean that a substance will cause cancer; the risk is influenced by the amount and duration of exposure a person has to the substance and a person’s susceptibility to the substance.

Among the latest additions, two fall into the “known carcinogen” category: the industrial chemical formaldehyde, and a group of botanicals known as aristolochic acids. Formaldehyde, once a member of the “reasonably anticipated” group, has been moved now that there is sufficient evidence to show that it can cause nasopharyngeal and sinonasal cancer as well as a myeloid leukemia. Aristolochic acids have been associated with high rates of bladder or upper urinary tract cancer in persons with renal disease who consumed botanical products containing these acids, which occur naturally in some plant species. The FDA advised consumers in 2001 to stop using any botanical products containing aristolochic acids.

Continue Reading

The remaining six substances to make the report are as follows:

  • Captafol, a fungicide used on fruits, vegetables, ornamental plants, and grasses, and as a seed treatment, has been banned in the United States since 1999, but a person’s health still may be affected by past exposure.
  • Cobalt-tungsten carbide (in powder or hard metal form; often referred to as cemented or sintered carbides) is used to make cutting and grinding tools as well as wear-resistant products often used in oil and gas drilling, mining, and several other industries.
  • Certain inhalable glass wool fibers—those that can enter the respiratory tract, are highly durable, and are biopersistent (remaining in the lungs for long periods)—may cause cancer, but the general-purpose fibers often used for home and building insulation appear to be less of a threat.
  • o-Nitrotoluene is used in dyes, agricultural chemicals, rubber chemicals, pesticides, petrochemicals, pharmaceuticals, and explosives. It has been detected in air and water near facilities that produce munitions and near military training facilities; exposure can occur through the skin or through inhalation during production and use.
  • Riddelliine, which is unrelated to the drug Ritalin, is found in ragwort, groundsel, and certain other plants in the daisy family (Senecio plants) that grow in sandy areas in the western United States and other parts of the world. Riddelliine-containing plants are not used for food in this country, but have been found in herbal medicines, herbal teas, or honey, and may have been consumed by animals from which our foods are produced.
  • Styrene is a synthetic chemical used worldwide in the manufacture of rubber, plastic, insulation, fiberglass, pipes, automobile parts, food containers, carpet backing, and other products. The greatest exposure to styrene in the general population is through cigarette smoking, although workers in certain occupations may be exposed to much higher levels of the substance than is the general population.