http://www.ergonomics.org.au/downloads/EA_Journals/EA_March_June_08.pdfInternational audienceThe crucial change that took place in the 19th century was that accidents became associated with the technological systems that people designed, built, and used as part of work, in the name of progress and civilisation. Suddenly, accidents happened not only because the people involved, today referred to as people at the sharp end, did something wrong or because of an act of nature, but also because a human-made system failed. Furthermore, the failures were no longer simple, such as a scaffolding falling down or a wheel axle breaking. The failures were complex, in the sense that they usually defied the immediate understanding of the people at the sharp end. In short, their knowledge and competence was about how to do their work, and not about how the technology worked or functioned. Before this change happened, people could take reasonable precautions against accidents at work because they understood the tools and artefacts they used sufficiently well. After this change had happened, that was no longer the case
