It’s official: HIV is “known to be a human carcinogen,” meaning it is a cancer hazard. This month, the U.S. Department of Health and Human Services (DHHS) added HIV and six other agents to its list of carcinogens, Reuters reports.

The list includes a variety of agents, such as X-rays, ultraviolet radiation, viruses and chemicals, and is divided into two groups: agents known to be a human carcinogen and agents reasonably anticipated to be a human carcinogen.

A total of 248 agents are now included on the list.

This year, five viruses were added to the category of “agents known to be a human carcinogen.” Combined, the five viruses have been linked to more than 20 different types of cancer. According to Reuters, the viruses added to the list are:

  • Human immunodeficiency virus type 1 (HIV-1)
  • Human T-cell lymphotropic virus type 1 (HTLV-1)
  • Merkel cell polyomavirus (MCV)
  • Epstein-Barr virus (EBV), which is a herpes virus
  • Kaposi sarcoma-associated herpes virus (KSHV).

There are no vaccines for these viruses, so prevention methods are important.

The chemical trichloroethylene (TCE), used as an industrial solvent, was added to the same category as the viruses. Added to the category of “reasonably anticipated to be a human carcinogen” were cobalt and cobalt compounds that release cobalt ions in the body.