Which substance is correctly classified as a carcinogen?

• A. Benzene
• B. Acetaminophen (Tylenol)
• C. Ethanol
• D. Cyanide

Answer: (A)

Carcinogens are agents that increase cancer risk by damaging DNA or promoting uncontrolled cell growth. Benzene is a well-established chemical carcinogen. When benzene is metabolized in the body, it forms reactive intermediates that can bind to DNA and cause chromosome damage in bone marrow cells. This genetic damage can lead to mutations and uncontrolled proliferation of blood-forming cells, which is why benzene exposure is linked to leukemia and other hematologic cancers. That strong human evidence and clear mechanism make it the best choice among the options. Acetaminophen can cause severe liver injury at high doses but isn’t classified as a cancer-causing agent; cyanide is a toxin that disrupts cellular respiration; ethanol is associated with cancer risk with long-term use, but benzene is the classic example of a chemical carcinogen in this list.