The 14th , a congressionally-mandated publication of the U.S. Department of Health and Human Services, was released in November and includes seven new substances: the chemical trichloroethylene (TCE), the element cobalt, and five viruses. With the exception of cobalt, all of the new substances are listed as “known to be a human carcinogen.” Cobalt is listed as “reasonably anticipated to be a human carcinogen.”

Among the new viruses is human immunodeficiency virus type 1 (HIV-1), which causes AIDS.

“Given that approximately 12 percent of human cancers worldwide may be attributed to viruses, and there are no vaccines currently available for these five viruses, prevention strategies to reduce the infections that can lead to cancer are even more critical,” said Linda Birnbaum, PhD, director of the National Institute of Environmental Health Sciences (NIEHS) and National Toxicology Program (NTP). “The listings in this report, particularly the viruses, bring attention to the important role that prevention can play in reducing the world’s cancer burden. There are also things people can do to reduce their exposure to cobalt and TCE.”

TCE is an industrial solvent that has been used by the military as a metal degreasing agent. The chemical is also used in small commercial shops and as a stain-removing agent in dry cleaning. An EPA risk assessment () published in 2014 identified concerns about cancer risk for users and bystanders occupationally exposed to TCE when using TCE-containing vapor degreasers and spot cleaners.

In addition to HIV-1, the other new viruses listed in the 14th are Human T-cell lymphotropic virus type 1 (HTLV-1), which can cause a rare type of leukemia-lymphoma; Epstein-Barr virus (EBV); Kaposi sarcoma-associated herpesvirus (KSHV); and Merkel cell polyomavirus (MCV).