Preventing fatalities in building bombings: what can we learn from the Oklahoma City bombing?

Background: Bombings are an increasing threat to the public's health. Descriptive studies of blast injuries have been published, but these injuries have not been studied using analytical epidemiological methods. This study assesses factors associated with fatality risk among individuals exposed to the 1995 Oklahoma City bombing.

Methods: Retrospective case-control analysis using multivariable logistic regression. Odds ratios (OR) of fatality are calculated among occupants of the Alfred P. Murrah Federal Building on April 19, 1995.

Results: Of the 348 occupants exposed, 163 (46.8%) were fatally injured. Fatality risk was greatest in the collapsed region of the building (adjusted OR 176.7, 95% confidence interval [CI] 65.9-474.2). Age > or =40 was also associated with a significantly increased risk of fatality (OR 3.7, 95% CI 1.4-9.8). Among people found in the noncollapsed region of the building, employees' status compared to a visitor's or child's status was protective (OR 0.13, 95% CI 0.01-1.3).

Conclusions: Structural collapse is the most important risk factor for fatality in a building bombing. Progressive collapse may be prevented through more supportive building design. Protection of vulnerable building occupants can be improved by placement of relevant facilities in more structurally reinforced areas. Regular evacuation training of personnel and clear egress routes may also reduce fatality in a building bombing.