Just Culture has shifted from being a theoretical notion for improving safety to a legislative reality. But there remains much misunderstanding and concern about how the notions of gross negligence and wilful misconduct that are traditionally used in the field of criminal and civil law should be interpreted. In this article, Florentino-Gregorio Ruiz Yamuza, Senior Judge in the Appeal Court of Huelva (Spain), discusses these issues, along with a number of possible implications for safety and justice.