A traditional view of incidents is that they are caused by shortcomings in human competence, attention, or attitude. It may be under the label of ''loss of situational awareness, '' procedure ''violation,'' or ''poor'' management. A different view is that human error is not the cause of failure, but a symptom of failuretrouble deeper inside the system. In this perspective, human error is not the conclusion, but rather the starting point of investigations. During an investigation, three types of information are gathered: physical, documentary, and human (recall/experience). Through the causal analysis process, apparent cause or apparent causes are identified as the most probable cause or causes of an incident or condition that management has the control to fix and for which effective recommendations for corrective actions can be generated. A causal analysis identifies relevant human performance factors. In the following presentation, the anatomy of a radiological incident is discussed, and one case study is presented. The contributing factors that caused a radiological incident are analyzed. Underlying conditions, decisions, actions, and inactions that contribute to the incident are identified. This includes weaknesses that may warrant improvements that tolerate error. Measures that reduce consequences or likelihood of recurrence are discussed.

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Metal-halide lamps produce light by discharging an electric arc through a gaseous mixture of vaporized mercury and metal halides. Metal-halide lamps for use in spaces with lower mounting heights can produce excessive visual glare in the normal, higher field-of-view unless they are equipped with prismatic lenses. Should the bulb fail, high internal operating pressure of the arc tube can launch fragments of arc tube at high velocity in all directions, striking the outer bulb of the lamp with enough force to cause the outer bulb to break. This article reports an investigation of a light fixture fire and reviews a case study of a metal-halide lamp fire. Causal analysis of the metal-halide lamp fire uncovered contributing factors that created the environment in which the incident occurred. Latent organizational conditions that created error-likely situations or weakened defenses were identified and controlled. Effective improvements that reduce the probability or consequence of similar metal-halide lamp fire incidents were implemented.

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