Just because the accident was very big does not mean the people involved are very bad.
As obvious as this sounds, common practice is still quite different: the outcome is a measure how 'bad' the event was, and automatically plastered on the supposed behaviour of the one who 'did' it. You will be well advised to try to avoid this! The exact same behaviour may never have given rise to worries before, so it was commonly accepted in the organization it was okay to do it like that.
Get yourself a mechanism where you will learn about everyday actions that do NOT result in accidents and find out why the actions were taken.