Short answers, pulled from the story.
A carcinogen is any agent that promotes the development of cancer by creating mutations in DNA. These agents include synthetic chemicals, naturally occurring substances, physical forces like ionizing radiation, and biologic entities such as viruses and bacteria.
The time from exposure to a carcinogen to the development of cancer is known as the latency period. For most solid tumors in humans this window spans between 10 and 40 years depending on the specific cancer type while blood cancers may have latency periods as short as two years.
CERCLA identifies all radionuclides as carcinogens regardless of their emitted radiation type or strength. The nature of the hazard depends on whether alpha beta gamma or neutron particles are involved and how deeply they penetrate tissue.
Approximately 6% of cancers and 4% of cancer deaths in the United States are attributable to alcohol use. Alcohol acts as a carcinogen affecting the head neck esophagus liver colon rectum and breast.
The International Agency for Research on Cancer formed part of the World Health Organization of the United Nations and established its agency in 1965. It is based in Lyon France and has published a series of Monographs on the Evaluation of Carcinogenic Risks to Humans since 1971.