The following information was provided by the
Wisconsin Department of Health Services (the Department) via email:
On November 20, 2025, the Department received notification that the licensee was unable to locate a RONAN Engineering model RLL-1 source holder (serial number 203389-D) containing an aggregate 0.72 millicuries of cesium-137. The source holder was discovered as missing by the licensee on November 14, 2025. The source holder contains eight cesium-137 sources, each with an activity of 0.09 millicuries. The source holder had been removed from service in September 2025 and was placed in storage. However, based on the licensee's internal investigation, it appears that a third-party contractor removed the source holder from storage, mistaking it as scrap metal. The source holder is believed to have been transported to a local scrap yard. The licensee performed multiple searches for the device at their site and at the scrap yard. The source holder has not been located but is believed to be intact. The Department performed a reactive inspection and physically verified the remainder of the licensee's inventory. The licensee has arranged for the manufacturer to dispose the remaining devices.
Wisconsin Event Report Identification Number: WI250020
THIS MATERIAL EVENT CONTAINS A 'Less than Cat 3' LEVEL OF RADIOACTIVE MATERIAL
Sources that are "Less than
IAEA Category 3 sources," are either sources that are very unlikely to cause permanent injury to individuals or contain a very small amount of radioactive material that would not cause any permanent injury. Some of these sources, such as
moisture density gauges or thickness
gauges that are Category 4, the amount of unshielded radioactive material, if not safely managed or securely protected, could possibly - although it is unlikely - temporarily injure someone who handled it or were otherwise in contact with it, or who were close to it for a period of many weeks. For additional information go to
http://www-pub.iaea.org/MTCD/publications/PDF/Pub1227_web.pdf