factors affecting occupational accidents in the construction industry (2009-2013)

background: there is a high prevalence of  occupational injuries due to accidents in construction industries which affect human health. therefore, the exploration and analysis of contributing factors of such accidents can lead to their prevention and the reduction of their consequences. this study was conducted with the aim to identify factors related to occupational injuries and the severity of their consequences on large construction sites in iran.  materials & methods: this study was an cross-sectional investigation on five-sequential-year accidents on large construction sites. data includeds the information of 500 human injuries due to accidents. data analysis was carried out using spss statistical software and statistical tests such as linear regression, independent sample t-test, and one-way anova. results: the mean accident frequency rate and accident severity rate was 4.71 and 216.28, respectively. the average age and job experience of injured workers were 29.18 ± 7.67 and 4.67 ± 3.9 years respectively, and had significant statistical difference with accident frequency rate and accident severity rate (p < 0.05). the association between accident indices and all factors related to accident type, equipment-related factors, unsafe condition and act and accident nature was found to be significant (p < 0.05). furthermore, the results showed that accident frequency rate and accident severity rate had a significant association with all factors related to health, safety, and the environment (hse) training, housekeeping and hse control measures (p < 0.05). conclusions: the results indicate that the occurrence and severity of construction accidents were due to the combination of failures in a collection of different contributing factors including demographical and organizational factors, accident type, factors related to work conditions and equipment, unsafe actions and conditions, nature of accidents, hse training and control measures, and accident time and place. therefore, to prevent and reduce the rate of such accidents, all these factors should be regarded.