Cancer by the numbers: How many are caused by the environment?

Cancer by the numbers: How many are caused by the environment?
http://www.environmentalhealthnews.org/ehs/news/environmental-cancers

"More than 60 percent of U.S. cancer deaths are caused by smoking and diet. But what about the rest? Some experts say a decades-old estimate that six percent is due to environmental and occupational exposures is outdated and far too low. But scientists most likely will never be able to tease out the true role of environmental contaminants. "It's like looking at strands of a spider web and deciding which one is important," said Dr. Ted Schettler, director of the Science and Environmental Health Network. A report by the President's Cancer Panel, released earlier this month, reignited the 30-year-old controversy about how large a role environmental factors play in the No. 2 killer of Americans."