Hellfire is a laser guided, anti-armor missle. It is generally fired from Apache hellicotpers, which can carry 16 of them. The "Predator" remote controlled drone carries one as well. A10's will be carrying them soon as well.
The fireball is huge, the result is just a little hole... about 1 inch diameter. However, the hole in a practice target is in a tempered steel plate over a foot thick. The idea is that the super-heated copper gasses go inside a tank, and the ammo stored inside the tank is ignited, providing the main source of the internal explosion. There is only a couple pounds of shaped charge in the missle. They sometimes fire them into buildings as well. If you hear on TV about one being used against some "civilian structure" in Iraq, and the structure blew up, it wasn't just someone's house, it was an ammo dump. The principal source of the explosion was the ammo stored inside the building.
The actuall "projectile" is just a very hot copper slug, surrounded by super-heated copper gas. This is basically how the ww2 "bazooka" worked, although on a much bigger scale.
Yes, the range safety procedures are very detailed. When one is fired, everyone is over 2X max range away from the launch pad and everyone is accounted for before the countdown happens. It is alot like mission control for the space shuttle.