The State provided the following information via email:
This Agency [Nebraska Health and Human Services] contacted the general licensee in November 2006 concerning their three NRD Inc. self luminous exit signs (Model T-4001, with 19.8 Curies of H-3 when shipped, Serial Numbers 24921, 24922 and 24923) which where shipped to the licensee in early 1986. The licensee discovered that in 1993 the store moved to a new location within the shopping mall. The signs were left in the original store location. This location went through a major renovation in 1993 at which time a demolition company gutted the entire store. The debris was disposed of by the demolition company. The mall's manager and the new store's representative do not know the name of the demolition company and do not know the current location of the three exit signs.
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.
This source is not amongst those sources or devices identified by the
IAEA Code of Conduct for the Safety & Security of Radioactive Sources to be of concern from a radiological standpoint. Therefore is it being categorized as a less than Category 3 source