The following information was received by e-mail:
On 10/14/10, a soil density gauge possessed by Cal Trans District 6 (Troxler Model 3440, S/N 30696, containing 8 mCi of Cs-137 and 40 mCi of Am-241), fell from the tail gate of a pick-up truck in which it was being transported from the job site on State Highway 198 near Visalia, CA. The soil gauge was subsequently recovered by the operator and his ARSO [Assistant Radiation Safety Officer]. The soil gauge was damaged. The damaged gauge was returned to its permanent storage area in Visalia, CA. The RSO was notified, investigated the incident and reported the incident to RHB [California Radiation Health Branch] on the date it occurred. The gauge was surveyed by the RSO using a Radiation Alert Inspector PGM survey meter at the Visalia Field Site on the date of the incident. The maximum radiation level identified was 0.3 mR/hr at 1 meter from the gauge. The gauge was leak tested by the RSO with negative [satisfactory] results. The dosimeters for the gauge operator and ARSO were processed, and no radiation exposures were recorded. The Cal Trans District 6 facility in Fresno was visited by RHB on 10/28/10, and three items of noncompliance were identified.
Until December 2, 2010, RHB was working under the assumption that the gauge was not lost, but was only damaged when it fell from the back of the truck and was never out of sight of the operator and/or ARSO. On December 2, 2010, RHB determined that the gauge was lost for a period of time between it falling from the truck and being recovered. Therefore, RHB now consider it as having been lost and are reporting it as such.
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