A few months ago the NY Times tried to analyze the safety risks (could planet earth get sucked into a black hole?) from a practical point of view:
One problem is that society has never agreed on a standard of what is safe in these surreal realms when the odds of disaster might be tiny but the stakes are cosmically high. In such situations, probability estimates are often no more than “informed betting odds,” said Martin Rees, a Cambridge University cosmologist, the astronomer royal and the author of “Our Final Hour.” Adrian Kent, also of Cambridge, said in a paper in 2003 reviewing scientists’ failure to calculate adequately and characterize accurately risks to the public, that even the most basic question, “ ‘How improbable does a catastrophe have to be to justify proceeding with an experiment?’ seems never to have been seriously examined.”
Unsurprisingly religious diy scientists are also inspired by the new doomsday machine. Here's a guy warning us that the LHC is actually a cosmic cannon. The story is this: the ANTICHRIST wants to return to earth but he can't because the Van Allen radiation belt is in the way. But now Satans evil buddies in the European Union have built the LHC and they are gonna use it to blow a big hole into this radioactive shield so Satan can creep through..