Some in Congress are concerned about the possible vulnerability of U.S. coastal areas to tsunamis and about the adequacy of early warning for coastal areas of the western Atlantic Ocean. This stems from the December 26, 2004, tsunami that devastated many coastal areas around the northern Indian Ocean, where few tsunami early warning systems currently operate. Caused by a strong underwater earthquake off the coast of Sumatra, Indonesia, the earthquake and ensuing tsunami together are estimated to have claimed as many as 300,000 lives. Affected nations, assisted by others, are pursuing multilateral efforts through the UNESCO's Intergovernmental Oceanographic Commission (IOC) to develop a regional tsunami detection and warning network to alert coastal populations around the Indian Ocean. Those efforts coincide with President Bush's plan for upgrading and expanding U.S. tsunami detection and early warning capabilities, which was released in December 2005. Some developed countries bounded by the Indian Ocean already have operating tsunami warnings systems. However, in some areas of these and in neighboring countries, there is no emergency management infrastructure to receive tsunami warnings. Local officials are incapable of rapidly alerting the public to evacuate or to take other safety precautions. However, most disaster management experts assert that an emergency management infrastructure is not just issuing tsunami warnings but also educating indigenous people and visitors about the potential dangers in the area; communicating evacuation options clearly; adapting to potential risks through construction of public shelters; conducting periodic evacuation drills; and producing tsunami inundation maps for guiding future land-use planning. Although the cost of the expanded network for the United States will run into millions of dollars for instrumentation and long-term maintenance, some suggest the benefits would far outweigh the costs. Others have questioned whether the risks of tsunamis outside the Pacific Basin justify the investment. To leverage costs international science agencies have suggested that global or regional warning networks be built upon existing ocean data collection systems, marine data buoys, tide gauge networks, coastal and ocean observation networks, the global seismic network, and use international telecommunications systems. Still, a global tsunami warning system would be most useful in countries that also have expansive national emergency management capability. President Bush pledged $37.5 million for upgrading the U.S. tsunami early warning system through 2007, which would expand a network of 10 deepwater tsunami detection buoys now operating to 32 for the Pacific and Atlantic Oceans, Gulf of Mexico, and Caribbean Sea. P.L. 109-13 provided emergency appropriations for FY2005 to procure, deploy, and maintain a comprehensive U.S. tsunami early warning network, and is supplemental to FY2006 appropriations. Tsunami-related legislation in the 109th Congress would support long-term systems operations and maintenance, public education, and modes of adaptation. Administration officials and some in Congress consider an upgraded U.S. system a first step toward building a global tsunami warning capability. This report will be updated as warranted.