Purpose: of the paper has been an attainment of the confirmation that improvement of the effectiveness and efficiency of the processes is indirectly connected with the definition and assurance of the human recourses, infrastructure and work environment needed and reflecting directly assurance of the occupational health and safety.

Design/methodology/approach: used for the analysis has included: collection of the information necessary for the risk assessment, identification of the occupational threats and their results, occupational risk assessment using standard method and intermediate events tree method as well as determination of risk acceptability and the proposition of improving actions in the process.

Findings: of analysis, which have been conducted, are as follows: the input of the improvement of every process is being determined by the choice of proper methods of analysis and assessment; in the aspect of the occupational health and safety management-methods of the occupational risk assessment. Practical implications: can apply in case of any organisation, which manages the occupational risk by usage of both: standard general method taking into account probability of the threats occurrence and severity of their results and improving detailed method taking into consideration probability of the initiating, intermediate and ending events occurrence and their results.

Originality/value: of the presented paper has been constituted by the methodology using the standard method fulfilling legal requirements connected with the obligation of the occupational health and safety assessment and the intermediate events tree method satisfying expectations linked up with the improvement of the process.