After years of focussing on infectious and degenerative illnesses, U.S. public health turned to the problem of accidents. Over the course of the twentieth century, safety practitioners repurposed the models of infectious disease control, risk-factor medicine, and biomechanics to improve the precision of injury data and to guide its applications. The resulting set of frameworks, methods, and practices, collectively referred to as ‘the epidemiology of accidents’, changed how health professionals analysed injuries but never produced a lasting consensus on appropriate safety interventions. This article uses the understudied history of home accident prevention to explain why mid-twentieth-century public health failed to prioritise injury control and what made home accidents especially intractable. During the 1940s, the American Public Health Association and U.S. Public Health Service collected statistics from communities across the country to determine the causes of home accidents and to inform local safety campaigns. These investigations were comprehensive but nonspecific, seeking to educate families about all the dangers of domestic space. After John Gordon published his influential study on accidents in 1949, this approach shifted from counting cases associated with risky behaviours and conditions to quantifying the extent to which isolable risk factors contributed to injuries. From the 1960s to 1970s, William Haddon changed accident prevention again, defining injuries as ‘abnormal energy exchanges’ and finding ways to minimise harm when accidents happened. Across these iterations, the epidemiology of accidents tried to identify, classify, quantify, and control the causes of home injuries but fell short of translating research into policy.