Economic success stories often have their downsides. The price for the rise of Basel's chemical factories to one of Switzerland's most important industries was paid by the workers, who were unprotected and unaware, exposed daily to health-damaging chemicals. Acute poisoning and chronic illnesses were commonplace in chemical production. Since the 1870s, factory doctors treated sick workers without investigating the underlying causes. It was not until the late 19th century that the still-young discipline of hygiene began to explore the connection between harmful substances and illnesses. In this context, it was not the harmful external influences that were identified as the main risk factors, but rather the workers themselves, who were framed as the real problem with the concept of the 'toxic body.' It was only with the emergence of modern medicine and its refined examination methods in the 1920s that a different mindset developed, which was reflected in the introduction of health and accident insurance. With regular occupational health examinations for at-risk workers, a preventive calculus also came into play, defining occupational diseases as 'social risks.'.