The purpose of the present work was to develop a methodology for the risk assessment in workplace for Huntsman Ternate plant, pursuant the Legislative Decree n. 81/08 and subsequent amendments. Huntsman internal procedure focused on the processes risk management, and it was developed in order to homogeneously classify accident scenarios in all Huntsman plants; but it wasn't effective to assess the hazards related to work operations and workplace. The first kind of events are heavier than occupational accidents, as well as less frequent; therefore, the application of Huntsman procedure as it was would have provoked a loss of significance of results obtained. Thus, it was elaborated a semi quantitative method of risk assessment in workplace, combining the techniques derived by the national regulations and the company procedure, in order to reach a more effective method to evaluate the risks and communicate to the associates the risks evaluation outputs.