As the investigative arm of Congress, the Government Accountability Office audits government efforts. As the public-policy research arm of Congress, the Congressional Research Service (CRS) provides objective analysis and data. Both have been exploring homeland security issues with recently updated CRS reports investigating nuclear attacks on seaports and water infrastructure. By one estimate, a 10-to-20 kiloton weapon, about the size of the one that devastated Hiroshima, detonated at a major U.S. seaport would kill 50,000 to 1 million people, cause direct property damage of up to $500 billion, and result in indirect losses of up to $1.2 trillion. These numbers may be largely speculative, but the threat is real, according to the CRS. The report urges Congress to consider defense in depth, including safeguarding foreign nuclear material, mitigating the economic impact of an attack, and wisely allocating funds among ports and other high-value targets. Water infrastructure. The vast U.S. water infrastructure consists of 77,000 dams and reservoirs; thousands of miles of pipes, waterlines, aqueducts, and sewer lines; 168,000 public drinking-water facilities; and 16,000 public wastewater treatment plants. Receiving scant attention so far, according to the CRS, have been wastewater treatment facilities. Destruction of chemical vessels at treatment plants could release toxic agents into the air, for example. Despite the threat, there are no federal standards or industry best practices for water infrastructure security, the CRS notes. In December, however, industry groups developed three security documents that cover the design of online contaminant-monitoring systems as well as physical security improvements for drinking water, wastewater, and storm water systems. Water facilities also recently formed a Water Sector Coordinating Committee to work with federal officials.