I got into a discussion about hell with a few Christians and they were all over the place on it. Here is a website that shows the Bible verses that support a fiery, horrible place of torture and fire that is not separation from God.Actually reading the bible and not listening to the preacher helps here. The idea of Hell being a fire and torture filled pit for sinners was added by Dante to make The Divine Comedy more interesting. All the Bible says about it is that it's an eternal separation from God and Heaven. Not terribly interesting and not something atheists, or even most people, would fear.
From what I can tell, the Christians who object to this idea object on mostly moralistic grounds that God should not be so evil as to torture people for all of eternity for an Earthly decision. If you go with Hell being separation from God, you have to give up that God is omnipresent.