HEART (human error assessment and reduction technique) is widely recognized a robust empirical tool in determination of HEP (human error probability) since prediction of human error is of paramount importance in marine industry (Williams, 1988). The method is successfully applied to a variety of domains such as aviation, railway, petrochemical, nuclear power plants, etc. The method has two fundamental parameters; generic error probability (GEP) and error-producing conditions (EPCs). The EPCs are the factors that affect the human performance negatively. The paper deals in principle with one of the methods used for human error probabilities estimation and it suggests its enhancement using analytic hierarchy process (AHP) (Saaty, 1980). Thus, quantification of the subjective judgements of experts during assessed proportion of affect (APOA) calculation is achieved in the course of HEP. To demonstrate the proposed approach, cargo loading operation in oil/chemical tanker ship is selected since the process is very critical to prevent loss of life and marine environment pollution. Consequently, besides its theoretical insight, the paper has practical outcomes to safety practitioners and maritime professionals for estimation of HEP in a specific task. (C) 2016 Elsevier Ltd. All rights reserved.