In a large company in São Paulo State, two work accidents were investigated using the Causal Tree Method (CTM), leading to the accurate identification of factors related to work organization as the causal factors for the accidents. These cases pointed to the role of organizational factors, such as improvised and temporary assignments to work stations and/or jobs, decisions about the performance of tasks left to unprepared workers, unavailability of proper tools and/or materials, and faulty information distribution within the company. Analysis of the accidents allowed for the presentation and discussion of the method (CTM), its lengthy application, its demands in terms of training, and its potentialities for accident prevention.