warning signs and its impact on decrease of accidents in a manufacturing factory

background: all recent accident models emphasis on multi causality of accidents. the suggested models emphasized on human roles in accident occurrence. the results of recent decade's studies have shown that the main causes of accidents are human and his/her unsafe acts. nowadays, application of warning signs is an important way to decrease unsafe acts . methods: in this study, the unsafe acts on a factory worker in hamadan were evaluated by safety behavior sampling method, observation and interview in 2002. after description of unsafe acts, the sample size was estimated 515 observations based on results of pilot study and sampling accuracy of 5% and confidence level to 95%. a questionnaire was used to collect the variables concerned to the workers. warning signs were used to control unsafe acts . results: the results showed that the workers unsafe acts prior to intervention were 31 %. the most important unsafe acts were lack of use or abuse of personal protective equipment with 89.4% of the total unsafe acts. the rate of unsafe acts reduced to 22.3% after intervention. the most important unsafe acts were also as the mentioned. the results were shown a significant difference between the rate of unsafe acts after and before intervention (p . conclusion: the findings of the present study showed that a considerable part of worker's acts was unsafe. today, unsafe acts are the basic elements of accidents in workers. therefore, the findings emphasize on decrease of unsafe acts by applying warning signs .