Can be dangerous, but they usually give warning for those who live near an active one.

About 500 Million people world wide live near an Active volcano. Luckily they tend to give warning before they erupt so the Death toll has the potential to be minimized assuming that Communication and evacuation efforts are smooth. And no matter how safe I may feel snuggled in Atlanta, It wouldn't hurt to remember that some Scientists claim that volcanoes killed the Dinosaurs. If it wiped them out I imagine a particularly large on can wipe us out as well given the right circumstances.

Can be dangerous if you live near one.