With so few accidents in the Atomic Energy Industry, new concepts and procedures of interest to the Health Physics profession will result from a critical analysis of each major radiation accident. A brief description of the reactor, its purpose, and operating history prior to the accident is followed by a comprehensive treatment of the health physics activities.Emergency personnel working under adverse conditions in radiation fields, ranging up to 800 r/hr, received whole body exposure doses up to 27 r: Many unique problems were associated with the recovery and decontamination of the bodies. Environmental monitoring revealed that thc airborne radioactive material was essentially all iodine 131 and was well below the Radioactivity Concentration Guide value for the offsite population. Analysis of soil and air samples indicated that the reactor building was quitc effective in containing the fission products during and following the excursion. Included is data on direct radiation levels experienced in the vicinity of SL-1 and the rate of decay of the primary source. The major lessons learned from the accident are summarized.

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