A California agency says second-hand smoke is to blame for some breast cancers.
The report isn't final yet, but it's already stirring a lot of controversy because some other groups looked at the same evidence and didn't reach the same conclusion. California's Air Resources Board, the same group that first linked second hand smoke to heart disease is a highly respected source. This time, the group reviewed 13 studies before reaching the conclusion that passive smoke may trigger breast cancer as well.
"As new studies come in, it's quite possible all these agencies will be persuaded this is rock solid. But this is the first to come to that conclusion," says Dr. Michael Thum, with the American Cancer Society.