Chemical Munitions Dumped at Sea near the Hawaiian Islands

Sea disposal was once internationally accepted as an appropriate method for disposal of excess, obsolete, and unserviceable conventional and chemical munitions. The past decade has seen an increase in the number and complexity of studies to assess the effects of historical munitions disposal in the oceans. The Hawai`i Undersea Military Munitions Assessment (HUMMA) is a comprehensive deep-water (300-600 meter) investigation designed to determine the potential impact of sea-disposed munitions on the ocean environment, and vice versa, at a disposal site south of Pearl Harbor, Oahu, Hawaii. Historical records indicated that as many as 16,000 mustard-filled bombs were disposed in this area following World War II. A secondary objective of HUMMA is to determine best practices and technologies for mapping and sampling sea-disposed munitions. The overarching result from five HUMMA field programs conducted over a decade is that the greatest risk from munitions derives from direct contact; there is little evidence that leakage from munitions into the surrounding environment has a direct pathway to affect human health and the impact on the surrounding environment in Hawaii is detectable only at trace levels. This finding should be modulated based on the quantity of physical samples, which were collected around <1% of the potential 16,000 bombs. In 2014 when the Jason 2 remotely operated vehicle (ROV) directly sampled the internal constituents of bombs, distilled mustard was recovered. Additionally, inconsistent with results from the 2009 and 2012 HUMMA sampling programs, during the ROV-based 2014 field program trace amounts of mustard agent and its breakdown products were detected at control sites. Both findings support a hypothesis that the impacts of sea-disposed munitions change over time. This presentation will describe the technical approach and results of the 2014 HUMMA field program using Jason 2.