The International Agency for Research on Cancer (IARC) has classified nitrates/nitrites as Group 2A carcinogens. The IARC does not directly classify nitrates or nitrites as carcinogens but rather lists “ingested nitrates or nitrites under conditions that result in endogenous nitrosation,” owing to their conversion to nitroso compounds through epidemiological investigation and animal experiments. Although there is no clear and direct evidence that nitrates pose carcinogenic risks to humans [1], controversy persists among the public, media, and academics regarding their potential risks to humans (Fig. 2.1).