The State provided the following information via email:
A truck carrying waste materials from Adams Steel in Anaheim set off the radiation alarm at the Simi Valley Landfill on 8/29/06. The landfill monitor reading was approximately 600K (bkg 4K). LA County [DELETED] responded to the landfill on 8/30/06 and identified the nuclide as Cs-137, with radiation levels of 13 mR/hr on the side of the truck, 1.2 mR/hr at 3 feet from the side of the truck, and background in the cab of truck. Based on these radiation readings, it appears the source is located approximately 1 foot inside of the truck and is approximately 10 milliCi in activity. A DOT exemption form was completed by LA County and the truck returned to the Adams Steel yard late on 8/30/06, and parked in a remote location. LAC completed their own 5010 (082906) on the response to Simi Valley.
RHB responded to Adams Steel on 8/31/06, and located an approximate 7 milliCi Cs-137 bare source, located approximately 3 feet from the top of the trailer load and approximately 1 foot in from the side of the trailer. The source was taken by RHB to hold until Adams Steel can arrange for disposal of the source.
California incident #083006
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.