Since the start of the Manhattan Project in 1942, the world has accumulated 1,875 tons of nuclear explosive materials, the equivalent of tens of thousands of enormously powerful bombs. An estimated 25 countries hold these materials today at hundreds of sites, sometimes in facilities with questionable security.
Terrorists could engineer a devastating attack against a civilian population or a large military installation merely by gaining access to a few pounds of these materials, because the designs of simple nuclear weapons are no longer secret. A stock of enriched uranium the size of a six-pack is all they would need to fuel a crude bomb as powerful as the one that destroyed Hiroshima in 1945.
Anxious officials in the United States have sought as a result to eliminate or at least better secure stocks of nuclear explosive materials around the world, with mixed results.
Some governments have balked at reducing or eliminating their stocks, arguing that the materials are important economic assets they have a right to keep. Some have resisted adopting stringent standards for securing their nuclear explosives, saying that rigorous precautions are unnecessary, too expensive and a barrier to the development of peaceful nuclear programs.
The United States, meanwhile, has mismanaged some of its domestic efforts to secure or reduce its own stockpile of nuclear explosive materials.
The Center for Public Integrity has been investigating the global effort to control dangerous nuclear explosives. Our aim is to shine a light on the gravest risks today, and on secretive but sometimes unsuccessful efforts to secure these materials.