Waste pickers' cooperatives are an important part of curb side collection, presenting different types of structures and responsible for the sorting and separation of recyclable materials. Within these places, the lack of resources, structure and hygiene are intimately related to the great part of the work accidents and the exposure of these workers to risky situations. Several tools in Security Engineering are being studied to minimize and control risks. Among these techniques, HAZOP (Hazard and Operability study) stands out as one that has proven efficient in managing risks in industrial processes and other areas of study. For the applicability of the technique in this study, interviews were conducted with the co-workers. The data were used to prepare a Preliminary Risk Analysis (PRA) and later to create new guiding words for the modification of HAZOP in order to consider the risk from human aspects in the activities. This work aimed to evaluate the HAZOP applied to evaluate errors related to human aspects in three waste pickers cooperatives in Campinas/SP and to compare the data obtained with the PRA. With the application of the PRA, 189 different deviations were identified and the pre-screening step was the one that most violated workers' risks. With HAZOP and using the content analysis tool to evaluate employees' perceptions, it was possible to identify 209 deviations by having the personal question (45%), followed by the managerial question (29%) as the main causes.