This paper introduces two models on procedures and safety and assesses the practical consequences these have for organizations trying to make progress on safety through procedures. The application of procedures is contrasted as rote rule following versus substantive cognitive activity. It reveals a fundamental double bind: operators can fail to adapt procedures when adapting proved necessary, or attempt procedural adaptations that may fail. Rather than simply increasing pressure to comply, organizations should invest in their understanding of the gap between procedures and practice, and help develop operators' skill at adapting.