To the occupational psycholalgist who studies accidents, an accident is a misfortune occasioning loss; a misfortune because there is always a large element of chance in an accident; and the loss, whether it be loss of health as in today’s topic, loss of life, loss of money, loss of tools, equipment, machinery, stores, buildings, is what makes it serious, so that our efforts are devoted to lessening the probability of accidents on the one hand, and their incidence on the other. Zero accident programmes are the current ideal in industry. The improbability of accidents presents a problem because our efforts are devoted to ensuring that as far as possible no-one experiences an accident, far less becomes involved in one. This problem is overcome by training, whose essential function is to give experience of the improbable as well as of the routine and probable. If work is entirely routine, it can be learned on the job; variety and the improbable necessitate training because practical experience takes such a long time to acquire. So my first hint of advice is that where there are accidents to avoid, safety training is essential. Training has then twofold aims; to provide us with action programmes, coping behaviour to ensure a satisfactory work performance and defence behaviour to deal with emergencies and stress situations. My first answer to the ques#tion “Why do people fail to observe safety precautions in high risk situations? is, therefore: “Perhaps they were not included in the training.” Resistance to safety training is unlikely, because it is a human characteristic to overestimate low probabilities. Forgetting safety training is much more of a danger, because you may provide programmes of appropriate action, but practice, which is an essential part of learning is difficult to come by. Assuming that training has been given, what other reasons can there be for unsafe behaviour? Quenault (1967) of the Road Research Laboratory, investigating road accidents, provided the basis of a