From Longman Dictionary of Contemporary Englishaccidents (will) happenaccidents (will) happenspoken used to tell someone who has broken something that they should not worry that it has happened → accident
Examples from the Corpus
accidents (will) happen• Everyone knows that hideous accidents happen, however precise modern weapons are supposed to be.• Which is exactly how accidents happen.• And if accidents happen, they happen.• But worse is the fact that the same accidents happen time and time again.• But some accidents happen because of their egocentric tendency to think of themselves as invulnerable.• Where he went, accidents happened.• Local fishermen say that, when accidents happen, the trawlers never stop.• Therefore, both over-confidence and under-confidence may play a part in creating an environment in which accidents happen more readily. 