Radioactive material in sealed sources is used in equipment designed to diagnose and treat illnesses (particularly cancer), irradiate food and medical products for sterilization purposes, detect flaws and other failures in pipeline and other types of metal welds, and determine the moisture content of soil and other materials. Until the 1950s, only naturally occurring radioactive materials, such as radium-226, were available to be used in sealed sources. Since then, sealed sources containing radioactive material produced artificially in nuclear reactors and particle accelerators have become widely available, including cobalt-60, strontium-90, technetium-99m, cesium-137, and iridium-192. Under the Atomic Energy Act of 1954, the states retain sole regulatory authority over most naturally occurring radioactive material as well as radioactive material produced in particle accelerators. Federal jurisdiction extends only to those materials used as a source of material for nuclear fuel or created as a result of irradiation in nuclear reactors. Radioactive material can be found in various forms. For example, cobalt-60 is a metal, while the cesium-137 in some sealed sources is in a powder form closely resembling talc. Radioactive materials never stop emitting radiation, but their intensity decays over time at various rates. The term “half-life” is used to indicate the period during which the radioactivity decreases by half as a result of decay. Radioactive materials are measured by their level of activity. The greater the activity level—measured in units called curies—the more radiation emitted, which increases the potential risk to the public if the radioactive materials are lost or stolen. Two types of licenses are associated with the use of radioactive materials— general licenses and specific licenses. A generally licensed device usually consists of a sealed source within a shielded device, such as gas chromatograph units, fixed gauges, luminous exit signs, or reference and check sources. These devices are designed with inherent radiation safety features so that persons with little or no radiation training or experience can use it. General licensees are automatically licensed without having to apply to NRC or an agreement state for a license and are subject to a variety of requirements under NRC’s or agreement states’ regulations. Furthermore, manufacturers are required to report quarterly to NRC the names of customers who purchase generally licensed devices. Examples of requirements general licensees are subject to under NRC’s regulations include: general licensees shall not abandon the devices; complying with instructions and precautions listed on device labels; performing tests to ensure radioactivity is not leaking from the device at least every 6 months, and, if leakage is detected, suspend operation of the device and have it repaired or disposed of by the manufacturer or another entity authorized to perform such work; and reporting to NRC or an agreement state the transfer of a device to another licensee or the disposal of the device. A company seeking radioactive material for uses that do not qualify for a general license must apply to NRC or, if it conducts business in an agreement state, to the appropriate state for a specific license. Its application must demonstrate how the use of the materials will meet the safety requirements in NRC’s or agreement states’ regulations. Applicants must provide information on the type, form, and intended quantity of material, the facilities in which the material will be used, the qualifications of users of the materials, and radiation protection programs the applicant has in place to protect their workers and the public from receiving excessive doses of radiation. The number of sealed sources in use today in the United States is unknown primarily because no state or federal agency tracks individual sealed sources. Instead, NRC and the agreement states track numbers of specific licensees. NRC and DOE have begun to examine options for developing a national tracking system, but to date, this effort has had limited involvement by the agreement states. NRC had difficulty locating owners of certain generally licensed devices it began tracking in April 2001 and has hired a private investigation firm to help locate them. Twenty-five of the 31 agreement states that responded to our survey indicated that they track some or all general licensees or generally licensed devices, and 17 were able to provide data on the number of generally licensed devices in their jurisdictions, totaling approximately 17,000 devices. NRC estimates that there are approximately 2 million licensed sealed sources in the United States. However, there is no single source of information in the United States to verify authorized users, locations, quantities, and movements of sealed sources. Separate systems are in place at NRC and in each agreement state to track the identities of specific licensees and the maximum quantity of radioactive material that they are authorized to possess. These systems do not, however, record the number of sealed sources actually possessed by specific licensees nor do the systems track movements (such as purchase, transfer, or disposal) of sealed sources by specific licensees. Licensees are required to maintain records for the acquisition and disposition of each sealed source it receives and inspections by NRC and/or an agreement state includes confirming inventory records. The Secretary of Energy and the Chairman of NRC established a working group in June 2002 to address, among other things, the options for establishing a national source tracking system and the potential for the use of technological methods for tagging and monitoring sealed sources in use, storage, and transit. This working group reported in May 2003 that a national source tracking system should provide a “cradle to grave” account of the origins of each high-risk source, and record how, by whom, and where a source has been transported, used, and eventually disposed of or exported. According to the report, such a system would help NRC and DOE to: monitor the location and use of sealed sources, detect and act on discrepancies, conduct inspections and investigations, communicate sealed source information to other government agencies, respond in the event of an emergency, verify legitimate ownership and use of sealed sources, and further analyze hazards attributable to the possession and use of sealed sources. The working group did not determine how data on sealed source licensees in the agreement states would be integrated into a national level system. While there are no complete data on the number of sealed sources in the United States, data are available on the number of specific licensees authorized to use sealed sources. Analysis of NRC’s specific license database and responses to our survey of the agreement states indicates that there are about 20,000 specific licensees in the United States (see figs. 1 and 2). The majority (nearly 80 percent) are regulated by the 32 agreement states, the remaining 20 percent of specific licensees are regulated by NRC. Our analysis of NRC’s license tracking system and responses to our survey of agreement states indicates that sealed sources for medical uses comprise the largest portion of specific licenses issued (see table 1). Fixed and portable gauges used in industry to measure density, moisture content, thickness, and so forth, are the next most prevalent use of sealed sources, with nearly 7,100 specific licenses issued nationwide. Over 570 specific licenses have been issued for industrial radiographers. In addition, there are 70 large irradiators (containing high levels, between 10,000 and 15 million curies, of cobalt-60) across the United States used for the sterilization of food and medical products, and 284 smaller irradiators (containing less than 10,000 curies of, in most cases, cesium-137 and cobalt-60) used in hospitals and other facilities for sterilization of smaller products, such as units of blood. The remaining specific licenses in the United States are issued for a variety of purposes, including, among other things, manufacturing and distribution of smoke detectors (containing small amounts of americium-241), academic research, and disposal of radioactive waste. While data exist on the numbers and locations of specific licenses in the United States, complete data are not available on the numbers of general licenses. In most cases general licensees are not required to apply to NRC or an agreement state for a license to possess and use a device. Therefore, in the past, data on general licensees have come from manufacturers of generally licensed devices that are required to report quarterly to NRC or the agreement states the names of customers purchasing generally licensed devices. According to NRC, approximately 40,000 general licensees possess an estimated 600,000 generally licensed devices in the United States. Although general licensees are required to follow NRC’s regulations, they traditionally have little contact with NRC. Mishandling and improper disposition of generally licensed devices has, on occasion, resulted in limited radiation exposure to the public and, in some cases, entailed expensive investigation, cleanup, and disposal activities. For example, two incidents occurred in New Jersey in 1997 involving luminous exit signs containing tritium. In May 1997, a 14-year old removed three tritium exit signs from a demolition site near his home and opened one sign exposing himself to radioactive material and contaminating his home. In October 1997, a patient at a state-run psychiatric hospital broke a tritium exit sign. While no injuries resulted, the state spent more than $200,000 cleaning up the hospital and disposing of the more than sixty barrels of radioactive waste—primarily contaminated carpeting, furniture, bedding, and other debris—from the incident. NRC amended its regulations effective February of 2001, to, among other things, better enable NRC to verify and track the location, use, and disposition of generally licensed devices. NRC focused its efforts to improve accountability over generally licensed devices on a small subset of devices that were determined to be of higher risk. The amended regulations include a requirement for general licensees to register with NRC devices that contain certain levels of radioactive material. General licensees would be charged $450 to cover the costs of the registration program. Beginning in April 2001, NRC mailed registration forms to about 2,800 of its general licensees. As of May 2003, approximately 61 percent of them had responded.