Understanding why accidents occur in the work place has a long and convoluted history. This paper adds to this corpus of research by investigating the relationship between an individual's level of cognitive failure, psychological stress, and work place accident occurrence. Retrospective analysis of accident-case individuals vs. control-match individuals on the General Health Questionnaire (GHQ) and Cognitive Failures Questionnaire (CFQ) was undertaken from amalgamated data of two Royal Navy databases. Individuals in the accident-case sub-sample had higher GHQ and CFQ scores when compared to matched-controls. Mediated regression analysis revealed high GHQ score predicted accidents but was transmitted through high CFQ scores. Individuals who are stressed are more likely to have an accident in the workplace because of a propensity for cognitive failures. A specific recommendation to reduce accident risk in the work-place is discussed.