A portion of the scenarios initiated in our facilities do not make it to an accident or even to an actual Loss of Containment (LOC). They are activated, progress to a certain point and then are prevented from doing harm by one or several safety barriers coming in. Sometimes, and this is more worrying, the safety barriers have failed or had been disabled or by-passed, and the LOC was avoided just by "luck". Take the example of cold embrittlement: a cryogenic fluid reached a carbon steel segment of pipe which became cold (as testified by a deposit of ice) but, this time, the pipe did not rupture. We do not want to take chances! As all PSSIs (Potentially Serious Safety Incident), this situation needs to be investigated because the scenario has been activated and we must act preventively to make sure it does not happen again.