Which of the following statement is correct related to the carcinogens?
1
A few well-known carcinogens are asbestos, nickel, cadmium, radon, vinyl chloride, benzidene, and benzene.
2
Substances known to cause tuberculosis are called carcinogens.
3
Certain chemicals, including benzene, beryllium, asbestos, vinyl chloride, and arsenic are known possible human carcinogens.
4
Chloroform, DDT, formaldehyde, and polychlorinated biphenyls (PCBs) are examples of human carcinogens.