In this study, the dynamic behavior and response of concrete and steel air tanks under explosive loading have been investigated. In order to accurately simulate the explosion phenomenon, numerical modeling has been performed using Abaqus software and the coupled Euler-Lagrangian (CEL) formulation to properly consider the interaction between the tank wall and the fluid inside it. In the numerical analysis, the explosive load from an air blast was applied to the structure using the CONWEP experimental model, and the behavior of the tanks in unreinforced and reinforced states with three types of polymer fibers (CFRP, GFRP, AFRP) was compared. Numerical results showed that the use of FRP polymer fibers significantly improved the structural performance of tanks against explosive loads, such that CFRP-reinforced tanks showed an average reduction of 28% in maximum displacement and 23% in critical stresses compared to the unreinforced state. Also, AFRP and GFRP reinforcements also produced 18% and 15% reductions in displacement, respectively. Analyses showed that a complete arrangement of FRP on the tank surface provides greater strength and stability than a partial arrangement. Overall, the findings of the present study prove the high efficiency of using polymer fibers in reinforcing reservoir structures against explosive threats and can be used as an effective solution in the field of passive defense to increase the resilience of critical infrastructure.