The United States has created a problem called uranium-233, a material suitable for the core of a nuclear weapon and among the most dangerous materials on the planet. If as little as 19 pounds of uranium-233 fell into the wrong hands, it could make an explosion that could destroy all of downtown Washington, D.C. or another city. This report documents surprising U.S. government mismanagement of the material. Our nuclear facilities may have done a poor job of keeping track of this dangerous material. Now, the Department of Energy has indicated it plans to waive safety requirements to dispose of it. All uranium-233 should be accounted for, stored safely, and disposed of safely. About 96 kilograms of uranium-233 may be unaccounted for. Specific estimates of the amount of uranium-233 in storage at certain sites widely vary, suggesting that material control and accountancy of the current U.S. inventory of uranium-233 requires greater attention. The Energy Department has indicated it plans to waive safeguards and safety requirements to dispose of nearly 2,000 pounds of these concentrated nuclear explosive materials by simply putting them in a landfill. This would be in disregard for international safeguard and security norms as well as the department's own nuclear security and radioactive waste disposal standards. The lack of priority given to this problem is underscored by the fact that the Energy Department's "desired timeline" for disposition of this material is set for 2018, some 20 years after significant environmental, safety, and security vulnerabilities were first officially identified by the department's Environment, Safety and Health Division of the Office of Science. The handling of uranium-233 by the Energy Department is troubling. This report will demonstrate that the Department of Energy has yet to meet the challenges of ensuring that all uranium-233 is accounted for and that it is stored in safe facilities or safely disposed of. If these challenges are not addressed, the American people continue to face unacceptable public safety and security risks with potentially deadly consequences.