A statistical study of control systems and accidents at work

Abstract Backstrom, T. and Harms-Ringdahl, L., 1984. A statistical study of control systems and accidents at work. Journal of Occupational Accidents , 6: 201–210. One purpose of the study was to get an estimate of the number of occupational accidents in Sweden in which a control system was involved. Another purpose was to get a picture of the structure of these accidents. The main source of information was the Swedish data system of occupational injuries. The number of accidents in connection with control systems has been estimated to be around 2000 per year, corresponding to 2% of the occupational accidents in Sweden, but for some types of equipment accident rates are higher. 177 accidents were selected and studied. The most frequent types of equipment involved were presses, transportation systems and cutting machines. Inadvertent start caused 84% of the accidents. In 19% of the accidents technical faults were observed. This figure was higher for some types of equipment e.g. transportation systems (28%). In one third of the accidents the operator had corrected a deviation in the material or the equipment. Thus, hazards in this kind of task seem to be a major problem. In 55% of the accidents the operator caused the inadvertent start. Some recommendations are given on the design of automatic systems.