The Too Late Show with Grim Reaper.

Most people don't know that tobacco smoke is radioactive, but it's true. Cigarette smoke contains the radioactive isotopes polonium-210 and lead-210. This is a problem the tobacco industry has known about since at least 1960. In fact, according to the U.S. Environmental Protection Agency (EPA), smoking is the number-one cause of radiation exposure. And tobacco's radioactivity may be one of the most important causes of lung cancer. How does it get there? First it's not unusual for the foods we eat to contain small traces of radioactivity. The plants we eat can absorb radiation from fertilizers and naturally occurring radon in the soil. Normally, that's not a problem. But tobacco is different. The sticky tar that comes from burning tobacco causes radioactive particles to stick to delicate tissues in the lungs and build up, over time, to dangerous levels. According to the EPA, smoking a pack and a half each day is equal to getting a chest x-ray each day, each year. That's a problem for smokers and those who breathe second-hand smoke, too.