BEWARE: 7 substances added to the list of human carcinogens

According to CNN, five viruses were included in the list, such as:

• Human T-cell lymphotropic virus type 1 (HTLV-1)
• Epstein-Barr virus (EBV)
• Kaposi sarcoma-associated herpesvirus (KSHV)
• Merkel cell polyomavirus (MCV)

All the viruses have been associated to more than 20 different types of cancer, as per the report.

An example is the HIV-1, which is the causative agent of an acquired immune deficiency syndrome (AIDS). The virus targets the immune system and suppresses it. Hence, the patient is more susceptible to infections and more likely to acquire another disease, a source said to CNN.

Moreover, trichloroethylene (TCE) was also included in the list. It is "an industrial solvent primarily used to make hydrofluorocarbon chemicals."

This agent is found in a vast amount among appliances and products. Furthermore, it is utilized to remove grease in metals, by the military, the NIH says.

Alongside with the benefits from TCE, it is now found to cause cancer in humans. The researches displayed a probable affiliation between the chemical and kidney cancer.

Another cancer-causing substance included in the list is cobalt. "Cobalt is a naturally-occurring element used to make metal alloys and other metal compounds, such as military equipment and rechargeable batteries," as said in the report. "The highest exposure occurs in the workplace and from failed surgical implants."

As per the NIH, cobalt is as well found in vitamin B12. Nevertheless, cobalt in this design does not render the release of ions. Therefore, not associated to create cancer.

If a person was exposed to any cancer-causing agent, it doesn't mean he/she will develop a cancer.

There are many factors that affect the formation of cancer to a human body. It is measured in the state of their immune system and lifestyles.

In addition, the length of exposure, and the volume of agent they were exposed to are potential factors.