Database of radiological incidents and related events--Johnston's Archive

Idaho Falls radiation accident, 1955

compiled by Wm. Robert Johnston
last modified 22 September 2007

Date: 27 July 1955

Location: National Reactor Testing Station, Idaho Falls, Idaho, United States

Type of event: exposure to radioactive source


A maintenance person involved in shutdown operations at a prototype propulsion reactor suffered injury from a small radioactive particle lodged in his ear. During shutdown operations, the worker was involved in grinding open access ports to the heat exchanger during which a mild blast of air impinged on the worker. The worker had failed to wear protective head covering and failed to shower following work in the contaminated area; further, no radiation monitors were located at the access points to the area. About one week later the worker was treated for ear drainage believed to be from an ear infection. Three days later the worker during a routine radiation check the worker was found to have a 0.07-millimeter particle in his left ear, producing 1 rad/hr at 3 cm. The radiation resulted in a perforated eardrum and 10% hearing loss in one ear from a several-thousand rad dose to the ear area. The worker was out of work for 12 days.

Consequences: 1 injury.


© 2007 by Wm. Robert Johnston.
Last modified 22 September 2007.
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