This review shows that impaired/shortened sleep is a major cause of accidents in industry and transport. The reason is either sleep pathology, voluntary (non-pathological) sleep reduction, or activity during the circadian low. Night or morning work is a prominent factor with regard to the latter two. However, the link between sleep restriction (or shift work) and safety is much better established in the transport industry than in other industrial areas. The reason is that driving a vehicle is a task with continuous demand for attention and immediate punishment for lapses, whereas industrial work in most cases does not have the same demands. Still, there are effects and the consequences may be far-reaching.