How rare are large, multiple-fatality work-related incidents?

Despite their salience, the prevalence of incidents that result in many work-related deaths is not well-documented. This study estimated probabilities of observing large scale work-related fatal incidents using 1995-2010 records from the Census of Fatal Occupational Injuries. A range of model estimates suggest approximately a one-in-four annual chance of observing an incident resulting in 20 or more work-related fatalities. The most likely contributors are aircraft incidents, and fires and explosions. The probability that a large scale incident occurs has declined in recent years due to a general decline in the number of fatal incidents, and due to a compositional shift away from those types of incidents more likely to result in large scale outcomes.