Environmental bonds are a means to accounting for future environmental costs, yet examples of application in real-life scenarios are scarce, and estimation of fairness of the bonds is still poorly explored. We examined a recent Mexican Pacific maritime accident in which the aid of extra environmental assessments addressing long-lasting effects was needed, and contributed to the decision-making process of environmental authorities by means of an arrangement based on the legal figure of the environmental bond. The basis to estimate the bond was the cost of activities needed to fulfill compensatory measures, specifically, the cost of research programs that would set a baseline for monitoring long-lasting damage to the bottom. In order to proceed with analysis of environmental bonds, we employed cluster analysis for comparing mean depth, grain size, and composition and abundance of benthic fauna at the three sites set for monitoring long-lasting effects, under the assumption that no differences would mean bond overestimation whereas differences would mean fairness. The results show that the three sites were different enough to justify the spatial setting of three separate sampling campaigns, and that the bond was reasonably not overestimated. The approach appears suitable to address in a semi-analytical way current inquiries regarding fairness of the environmental bonds and so may contribute to the state of the art.