Social Factors Can Outweigh Biological Ones in Determining Night Shift Safety

Abstract

Ten years of mining accidents were surveyed in order to determine the pattern of changes over a seven-night span of duty. Sunday nights always occurred as the fourth night shift. Contrary to the gradually decreasing pattern predicted by biological clock adjustment, Sunday nights were by far the worst for accidents, suggesting that the social disruptions of the night worker on weekends may be far more potent than the biological ones.