"Parents need to be aware that this is very dangerous, and they need to take actions to ensure that their children are not exposed," Pechacek said.

Doctor Terry Pechacek at the C. D. C. says the findings should persuade every country that smoking in enclosed Spaces is very dangerous to nonsmokers.

"This is the most dramatic indication that the great progress we're making has stalled," said Terry Pechacek of the federal Centers for Disease Control and Prevention in Atlanta.