Cook and Woods 1 , in a seminal article, point ways to overcome the notion of 'human error' as an explanation to industrial incidents and their investigations. In the nine steps the authors proposed, analyses should (1) seek 'second stories' to explain events b , (2) protect themselves from experts' hindsight bias, (3) know operators' work, (4) seek 'systemic vulnerabilities', (5) unveil the production of safety by practice, (6) search for factors distal to the event, (7) examine how macro-determinants produce new vulnerabilities, (8) use technologies to support and favor operators' performance, and (9) control the complexity of systems by new forms of feedback.These authors' conception of safety is not inherent to the design and operation of production systems, i.e., not only assured by technological choices, equipment maintenance, strict compliance to procedures, and the control of operators' behavior. In the case of complex systems, interrelations between several functions and process variables can lead systems to an operating state with which operators are unfamiliar. Thus, certain circumstances normalize the occurrence of possible incidents which operation teams fail to detect.