Significant challenges are found in managing the potential risks of sea-disposed unexploded ordnance and munitions now underwater (collectively referred to as underwater munitions), which can pose risks to human health and the environment. Such risk encompasses two categories: acute risk, which addresses immediate injury or death resulting from either detonation of explosives or direct exposure to toxic chemical agents, and chronic risk, which addresses adverse health impacts typically resulting from prolonged exposure to munitions constituents, such as copper or lead. The author discusses actions by the United States in managing such risks, including a historical perspective. It is argued that managing risk requires a balance of potential response alternatives to protect the environment and human health within available resources. The foundation on which a long-term risk management strategy must be built is formed by sound science. In order to assess the potential impacts of munitions on the marine environment and determine the circumstances under which the impacts might prove unacceptable, continued scientific research is necessary. Reasonable and balanced understanding of associated risk must form the basis of decisions concerning sea-disposed munitions in the marine environment.