The purpose of this article is to better understand the challenges of avoiding the dark side of technological innovation. Specifically, we analyse 10 public investigations started as a reaction to a major crisis in regenerative medicine at the Karolinska Institute, Sweden, associated with the clinician-scientist Paolo Macchiarini. We interpret the reaction as an attempt to restore the balance between the stimulation and regulation of technological innovation processes by clarifying ambiguities in the regulation at the interface between research and practice. We conceptualise these ambiguities as grey zones–situations when it is unclear if the benefits of experimentation outweigh its risks–and propose that grey zones are continually created and resolved as actors in innovation governance systems counterbalance the generation of novelty and the risk of negative unintended consequences. © 2020, © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.