The document discusses several theories of accident causation that attempt to explain why accidents occur, including: - Domino Theory: Accidents result from a series of factors including unsafe acts and conditions. Most are due to unsafe behaviors. - Human Factors Theory: Accidents are caused by human error factors like inappropriate activities, overload, and inappropriate responses. - Accident/Incident Theory: Builds on human factors theory, adding elements like ergonomic traps and systems failure. - Epidemiological Theory: Looks at causal relationships between environmental factors and accidents, like predisposed characteristics, susceptibility, and situational characteristics.