 Radioactive materials, called sources, have many beneficial uses for our society. To protect public health, they are used to sterilize medical supplies, kill harmful organisms in foods and spices, and sterilize harmful insects that could damage crops. In manufacturing, they are used in fixed gauges to measure a wide variety of processes, including maintaining the proper fill on your bottled water and soda. Other gauges are used to measure moisture and density of soil, metal, and concrete to ensure structural integrity of roads, buildings, and bridges. In medicine, sources are used to treat cancer and other diseases. They can also be used to detect smuggled contraband, including other radioactive materials. While radiation sources provide many benefits, they can be dangerous if not handled properly. The possibility that these materials could be used by terrorists to expose people to radiation or spread radioactive contamination with a dirty bomb is a national security concern. The Nuclear Regulatory Commission works with other federal agencies, state regulators, and international partners such as the UN's International Atomic Energy Agency to help ensure the safety and security of the most risk-significant radiation sources at home and abroad. First line of defense is licensing. The NRC and state governments license and regulate the use of radioactive materials. This oversight ensures that only qualified people use these materials for proper uses. Background checks confirm the trustworthiness and reliability of personnel granted access to the most risk-sensitive sources. Three web-based information platforms, the web-based licensing system, the license verification system, and the national source tracking system form an integrated source management portfolio. Together these systems help authorities know who has what sources and where. In the second line of defense, licensees are required to have security plans or procedures to detect, assess, and respond to unauthorized attempts to access radiation sources. They are required to have security barriers to discourage and prevent theft of devices that contain radioactive material. They must also coordinate with local law enforcement to ensure an adequate response should a security event occur. Finally, the NRC cooperates with other federal agencies and state partners to identify potential security threats. If the threat comes from mother nature such as a flood or hurricane, we check with licensees to ensure their radioactive materials remain secure. And when a large source is no longer used or needed, the NRC requires that the source be safely stored or disposed of. In many cases, the NRC has worked with the Department of Energy and state regulators to collect and dispose of radioactive material that is no longer in use. The NRC's security requirements for radioactive materials are consistent with international recommendations in the IAEA's Code of Conduct for the Safety and Security of Radioactive Sources. We work internationally through the IAEA to help other countries improve their security programs and prevent theft of radioactive material overseas that could pose a threat to the United States. Because ensuring that our society can benefit from radioactive materials safely and securely is a 24-7 responsibility and a worldwide mission.