Objectives. Improving knowledge about the mechanism of accident occurrence in the construction industry provides important information to help design and implement appropriate barriers to stop the spread of unexpected events. This study characterizes the sequence of accidents in the construction industry by linking the most commonly identified circumstances, the barriers and barrier functions infringed and the specific way in which each of these functioned. Methods. In order to achieve the proposed objective, an analysis was made of 241 investigations of work accidents that occurred in the construction sector in Spain between 2009 and 2014. The statistical difference between the groups of variables was determined using contingency tables in which the value of the χ2 statistic was calculated. Results. The results obtained show that behavioural factors are fundamentally identified, such as the worker's non-observance of ensuring their own safety or the deficient interpretation of rules. Conclusions. This study illustrates that to understand the performance of barrier systems and functions, efforts must be focused not only on the things that go wrong, i.e., accidents, but also on the things that go right within the variability of daily performance in systems as complex as the construction industry.
Keywords: barrier systems and functions; construction industry; occupational accidents; occupational health and safety; variable deviation.