Accident research, aimed at explaining causal relationships, started as far back as the late 1920s, with the study of small but frequent accidents at work before shifting, particularly during the 1980s, to the current sophisticated methods, which focus generally on major accidents in high-hazard and high-tech industries. Currently, typical research fields are, for instance, nuclear power plants, aviation, chemical process and offshore oil industries. Recent developments in the field of Health and Safety (H&S) Management Systems (e.g.: OHSAS 18001:1999), however, combined with pressure from new and more strict legal requirements, has prompted attention to be put onto the important role of both pro-active and reactive monitoring of H&S performance. A direct implication is that accident research is shifting (again) towards ordinary but frequent occupational accidents.