A century after the first laws on the protection of occupational health and safety were passed, the accident and morbidity rates are still persistently high. Does this mean that European companies are less adverse to this kind of risk than to other risks for which the principle of precaution trends towards zero? Is occupational risk acceptable? This paper investigates the processes of risk identification and recognition as well as those of rule implementation to shed the light on factors that hinder progresses in occupational health and safety. We can distinguish three main different obstacles: unequal access to a scientific knowledge, financial interests, operational brakes, and cultural biases. It is only in the 1970s, under the pressure of new social conflicts and of the EEC in the next decade that efficient policies of prevention were introduced.