The explosive removals of offshore structures (EROS) impact marine life. In order to assess that impact adequately, a methodology is needed that accurately models the shock effects caused by the detonation of an explosive charge below the mud line (typically 15 feet) inside a pile, leg, conduit or other structural element. Current methodologies do not take the effects of an explosive detonating below the mud line and the pile leg confinement into consideration in determining shock characteristics in the water at distances. This effort investigated the reduction of energy transmitted to the water resulting from the below-the-mud-line detonation inside a pile or leg. A method was developed that calculates the effectiveness of the explosive as a function of the pile diameter and wall thickness, and the weight of explosive used.