We validate the RBAC ANSI 2012 standard using the B method. Numerous problems are identified: logical errors, inconsistencies, ambiguities, typing errors, missing preconditions, invariant violation, inappropriate specification notation. A clean version of the standard written in the B notation is proposed. We argue that the ad hocmathematical notation used in the standard is inappropriate and we propose that a more methodological and tool-supported approach must definitely be used for writing standards, in order to avoid the issues identified in the paper. Human reviewing is insufficient to produce error-free international standards