The building construction site is notably prone to both lethal and non-lethal occupational risks, largely due to prevalent unsafe acts and conditions. Despite the frequent occurrence of these risks, there has been insufficient evidences for the adoption of risk management approach by safety decision-makers to underscore the probability of risk occurrences and their potential impacts on construction workers on sites which often hinders effective risk management on sites. This study addressed this gap by conducting a detailed analysis of occupational risks associated with various building construction works on sites with a view to establish the probability of risk occurrences and their potential impacts on construction workers on sites in Nigeria. A quantitative research design was adopted for data collection in the study. A structured questionnaire designed in Likert scale 1–9 was used for data collection through a random sampling technique. The fuzzy synthetic evaluation (FSE) approach was used for the risk assessment. Findings from the study revealed formwork as the highest risk score of 2.75, indicating significant probability and impact concerns, while hardcore filling is the lowest at a risk score of 1.39, categorizing it as “Low” risk. Notably, several construction tasks, such as finishing in ceiling and cladding work, exhibited similar probability classifications, resulting in overall risk scores within the low-medium range (2.235 and 2.339, respectively). The findings suggest that safety and health programs are the prevalent risk management strategy employed, demonstrating a significant reliance on systematic evaluations to enhance safety across construction sites. The study recommends an inclusive risk assessment for construction works on site to inform safety officers and project managers about potential risks and their potential impacts on workers.