This BBC article indicates that there is “no conceivable danger” from the Large Hadron Collider (LHC), including the danger from any possible mini-black holes that might be formed. But, Dr. Adrian Kent expresses concern that:
So? Are we worried at all about the LHC going to full start-up? Is the earth going to be destroyed by mini black holes or strangelets after it goes online? They are, after all, going to cross the streams.