Industrial Accident Prevention. A Scientific Approach.
H. W. Heinrich's 1941 second edition presented a broad approach to industrial accident prevention, covering accident causation, machinery, management, worker education, fatigue, occupational disease and systematic investigation of workplace incidents.
What the study did and found
H. W. Heinrich's 1941 second edition of “Industrial Accident Prevention. A Scientific Approach.” was a practical safety text for industrial executives, personnel managers and others responsible for workplace conditions. It discussed accident facts, machinery, safety psychology, fatigue, occupational disease, safety organisation, statistics and employee education. Heinrich argued that many accidents involved human failure, while also maintaining that safer environments could reduce accidents even among workers considered accident-prone. The book gave particular attention to safer machine design, guards, barriers, mechanical feeding, interlocks and remote controls. It also promoted detailed investigation and recording of individual accidents, alongside management commitment and worker and foreman education.
Why it is cited
The book is cited in the history of occupational safety because it helped formalise early accident-causation models and practical prevention methods. Heinrich's later-famous domino model and his emphasis on unsafe acts became influential reference points in safety management literature. At the same time, later authors frequently cite the work when discussing the limits of behaviour-centred explanations of accidents.
Several practical themes in Heinrich's book remain consistent with modern safety practice, especially hazard investigation, machine safeguarding and designing hazards out of work systems. However, modern accident science no longer treats worker behaviour as a sufficient explanation for most incidents. Contemporary approaches examine interacting technical, organisational and human factors, and place greater emphasis on elimination, substitution and engineering controls before administrative measures or personal protective equipment. Heinrich's numerical claims about the proportion of accidents caused by unsafe acts are therefore best treated as historical, not as a current evidence standard.
The topic today
Current occupational safety programmes use structured hazard identification, risk assessment, incident investigation and a hierarchy of controls. Engineering solutions such as machine guarding remain central, but prevention now also considers work design, management systems, maintenance, communication, organisational pressures and worker participation. Heinrich's 1941 book remains useful for understanding the development of industrial safety thinking, while modern practice uses broader systems-based models rather than a simple linear chain of accident causes.