This paper investigates how rule violations that contributed to the Chernobyl nuclear
disaster were able to happen. Bringing to the surface what is implicit in historical
documents, we argue that six excuses can be identified that could have allowed the
operators to rationalise their rule violations. These excuses could have affected
how the operators interpreted the applicability of the rules to the situation(s) they
were involved in, leading them to ultimately violate the operational rules. As a theoretical
consequence, rule-following as (com)pliance or obedience is to be taken as a necessary
but insufficient condition of rule-following. As a practical consequence, the concept
of 'excuses' can also help to anticipate as well as prevent rule-breaking behaviour
in similar future cases.
