The U.S. Armed Forces disposed of chemical weapons in the ocean from World War I through 1970. At that time, it was thought that the vastness of ocean waters would absorb chemical agents that may leak from these weapons. However, public concerns about human health and environmental risks, and the economic effects of potential damage to marine resources, led to a statutory prohibition on the disposal of chemical weapons in the ocean in 1972. For many years, there was little attention to weapons that had been dumped offshore prior to this prohibition. However, the U.S. Army completed a report in 2001 indicating that the past disposal of chemical weapons in the ocean had been more common and widespread geographically than previously acknowledged. The Army cataloged 74 instances of disposal through 1970, including 32 instances off U.S. shores and 42 instances off foreign shores. The disclosure of these records has renewed public concern about lingering risks from chemical weapons still in the ocean today. The risk of exposure to chemical weapons dumped in the ocean depends on many factors, such as the extent to which chemical agents may have leaked into seawater and been diluted or degraded over time. Public health advocates have questioned whether contaminated seawater may contribute to certain symptoms among coastal populations, and environmental advocates have questioned whether leaked chemical agents may have affected fish stocks and other marine life. There also has been public concern that chemical weapons could wash ashore or be accidentally retrieved during activities that disturb the seabed, such as dredging and trawl fishing. Although such incidents have occurred domestically and abroad, they are rare relative to the thousands of weapons dumped in the ocean. Assessing the degree of risks is difficult because of a lack of information. Whether the risks are low or high, how to respond to them is fraught with many challenges. The primary obstacle is locating the weapons in the ocean. The lack of coordinates for most of the disposal sites, and the possibility that ocean currents may have moved weapons beyond these areas, makes finding the weapons difficult at best, if not impracticable in some cases. As signed into law, H.R. 5122 (P.L. 109-364) requires further review of historical records to attempt to identify where chemical and conventional weapons were dumped off U.S. shores, research of the effects of these weapons on the ocean environment, and monitoring if contamination or health or safety risks are present. As introduced, H.R. 4778 and S. 2295 include similar requirements for chemical weapons disposal sites off the coast of Hawaii. In the event that the weapons are located, retrieving them from the seabed could be technically challenging and could introduce new risks during retrieval and transport for onshore disposal. Leaving located weapons in place, and warning the public to avoid these areas, may be more feasible and involve fewer immediate risks. However, long-term risks would remain. Responding to potential risks is further complicated by insufficient information to reliably estimate response costs and by the uncertain availability of federal funding to pay for such actions.