Cigarette Smoking and Cancer
The health risks caused by cigarette smoking are not limited to smokers. Secondhand smoke is a combination of the smoke that is released from the end of a burning cigarette and the smoke exhaled from the lungs of smokers. Exposure to secondhand smoke, or environmental tobacco smoke (ETS), significantly increases the risk of lung cancer and heart disease in nonsmokers, as well as several respiratory illnesses in young children.
The US Environmental Protection Agency (EPA), the National Institute of Environmental Health Science's National Toxicology Program, and the World Health Organization's International Agency for Research on Cancer (IARC) have all classified secondhand smoke as a known human carcinogen -- a category reserved for agents for which there is sufficient scientific evidence that they cause cancer.
The EPA has estimated that exposure to secondhand smoke causes about 3,000 lung cancer deaths among nonsmokers annually and is responsible for up to 300,000 cases of lower respiratory tract infections in children up to 18 months of age in the United States each year.
Cigarette smoke contains about 4,000 chemical agents, including over 60 carcinogens. In addition, many of these substances, such as carbon monoxide, tar, arsenic, and lead, are poisonous and toxic to the human body.
Nicotine is a drug that is naturally present in the tobacco plant and is primarily responsible for a person's addiction to tobacco products, including cigarettes. During smoking, nicotine is absorbed quickly into the bloodstream and travels to the brain in a matter of seconds. Nicotine causes addiction to cigarettes and other tobacco products that is similar to the addiction produced by using heroin and cocaine.