[Variations over time in the accident rate in an automobile manufacturing plant]

This paper describes some characteristics of occupational injuries occurring in a car manufacturing plant during the period 1984-1991. Data regarding all kinds of injuries (not only those which received compensation) were extracted from records compiled by health personnel within the factory according to a sampling scheme that considered the same three months every two years. In addition, all injuries which caused absence from work lasting more than three days were evaluated (without sampling). To compute frequency indexes, the number of hours worked each month/year were obtained. Roughly 650 occupational injuries per million hours worked occurred in the whole population without appreciable changes over time: about 90% of the events did not cause absence from work. For two-thirds of the injuries that caused absence from work, the absence lasted more than three days. More than 50% of the injuries involved the hands; the eyes and arms followed with lower percentages. Cuts/lacerations comprised 45% of all injuries, followed by contusions and foreign bodies. Over time, the frequency index of foreign bodies in the eyes diminished, whereas muscular disorders increased, mainly in the last period. Compensated injuries were particularly elevated in the final period and lowest in the middle: this pattern is attributable only to events with temporary consequences. The increase in the incidence of injuries in the last period was observed in all categories of duration of absence but the decrease of incidence in the middle period concerned only events with shorter duration (less than fourteen days' absence). These trends can be partially attributed to the changes in health management within the factory (recognition and first aid) which occurred in the time period considered. Some combinations of site and type of lesion (i.e., foreign bodies in the eyes) showed a decrease over time both for index of frequency and mean duration of absence; others had a particular pattern: decrease in frequency and increase in mean duration of absence in the middle period, followed by an opposite pattern in the last period (i.e., cuts/lacerations of the hands); some others showed a decrease both for frequency and duration of absence (sprains/strains of the vertebral column muscles).