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| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 55622 | 27 October 2021 08:00:00 | Agreement State | Agreement State - Occupational Overexposure | The following was received from the Washington State Department of Health, Office of Radiation Protection, via email: Dosimetry results for the month of October 2021 for one employee showed ring extremity dosimeter readings of 77,156 millirads for one hand and 29,391 millirads for the other hand. The employee was interviewed and it appears that the radiation exposures were received during experiments involving yttrium-90 radiolabeling and injections into mice on October 25-27, 2021. The activity used during the experiments is not known at this time, but they had received a shipment of 40 milliCuries of yttrium-90 just before these experiments. This event is still being investigated by the licensee, but some (preliminary) calculations using the `beta activity to dose-rate' online calculator in Rad Pro Calculator suggest that the high dosimetry results could have been caused if the outside of the employee's ring extremity dosimeters were contaminated with as little as a few thousandths of a microCurie of yttrium-90. This possibility of contamination on the ring extremity dosimeters is also supported by the employee's low whole body dosimeter results for the month of October 2021, which were 0 millirems deep dose, 45 millirems lens dose, and 97 millirems shallow dose. The much lower dosimetry results of a coworker who was working alongside of the exposed employee also suggest that contamination on the ring extremity dosimeters of the exposed employee may have been the cause. The coworker's results were ring extremity dosimeter readings of 6025 millirads on one hand and 889 millirads on the other hand, and whole body dosimeter results of 0 millirems deep dose, 32 millirems lens dose, and 68 millirems shallow dose. Washington Reference Document Number: WA-21-025 | ||
| ENS 40085 | 19 June 2000 19:00:00 | Agreement State | Overexposure | Exposure (intended/actual): consequences: Actual exposure received was Licensee: Fred Hutchinson Cancer "Research Center City and state: Seattle, Washington License number: WN-L042-1 Type of license: Medium Broad License Date of event: Reported by licensee on 19 June 2000, (indicated overexposure for the wear period between 5 April to 4 "May 2000). Location of Event: Seattle, Washington ABSTRACT: (where, when, how, why; cause, contributing factors, corrective actions, consequences, DOH on-site investigation; media attention) On 19 June 2000, the licensed RSO reported that their dosimetry badge provider (Landauer Inc.) had notified them that one of the Fred Hutchinson employees had apparently received an exposure of 317,791 millirem of high energy gamma radiation. This employee performs animal studies involving irradiations using both a Linac and a Cobalt 60 irradiator (a J.L. Shepherd Model 285, Serial Numbers 625 & 626). The RSO immediately started an investigation of the reported overexposure. The RSO discovered that the individual's dosimetry badge had been lost during the second week of April 2000 for a period of about one week. An unknown person, via the inter-office mail system, returned it to the individual the next week. The employee was unable to recall any situation that would have lead to an exposure of any amount greater then the usual for the work performed over that time period. Several circumstantial events as well as actual occurrences seem to indicate that the exposure was probably only received by the dosimetry badge. These were: first, the employee indicated that the dosimetry badge had been lost during the second week of April 2000, for a period of about one week. Second, only the Cobalt 60 irradiator was in operation during that period; the Linac was out of service then. Third, since several groups share use of the irradiator, the badge conceivably was found, in the irradiator room, by one of those people and returned in the inter-office mail system. Lastly, the employee never experienced any radiation related illnesses. The reported exposure of 317,791 millirem was removed from the employee's exposure history and replaced with a 20 millirem exposure (average monthly exposure for previous 12 months). No DOH on-site investigation was made or media attention was noted. What is the notification or reporting criteria involved? 10 CFR 20.2202 (a)(1) significant . After reviewing our incident files and the Handbook on Nuclear Material Event Reporting in the Agreement States , we determined that an immediate notification should have been sent to NRC. This did not occur; consequently we are now submitting this completed report, although late. Activity and Isotope(s) involved: 518 terabecquerels (1400 curies), cobalt 60. Overexposures? (number of workers/members of the public; dose estimate; body part receiving dose; consequence) The initial notification indicated that one worker (employee) had been overexposed. The event did not involve a member of the public. The Landauer report indicated that an employee had received a whole-body exposure of 317,719 millirem of high-energy gamma radiation. No consequences will be realized since the exposure was later determined to only involve the dosimetry badge. The employee's exposure history was revised to indicate a 20 millirem exposure for that period of wear. Lost, Stolen or Damaged? (mfg., model, serial number) The employee's dosimetry badge was lost for a period of about one week. Disposition/recovery: Badges were to be used by placing them into a pouch for individuals using the irradiator devices. Leak test? N/A Vehicle: N/A Release of activity? None Activity and pharmaceutical compound intended: N/A Misadministered activity and/or compound received: N/A Device (HDR, etc.) Mfg., Model; computer program: J.L. Shepherd Model 285 irradiator. Exposure (intended/actual): consequences: Actual exposure received was estimated to be the usual, average amount of 20 millirem for that wear period. Was patient or responsible relative notified? N/A Was written report provided? Yes, from licensed RSO dated 21 July 2000. Was referring physician notified? N/A Consultant used? No Washington State Event Report # WA-00-023. |