Abstract
This article examines the rise of the Centers for Disease Control and Prevention's (CDC's) small but influential program on the human toxicology of synthetic pesticides after World War II. For nearly 20 years, scientists working in the CDC's Toxicology Section conducted a range of laboratory, field, and clinical studies to assess whether pesticides, such as dichlorodiphenyltrichloroethane (DDT), caused harm to humans. Applying an industrial hygiene approach to study pesticide toxicity, the team used the symptoms of poisoning as their criteria for harm and consistently found that, when used as intended, pesticides were generally safe for humans. In the post-Silent Spring era, these findings were increasingly challenged as the field of toxicology developed and different ways of understanding pesticide toxicity gained greater acceptance. While it is easy to dismiss the CDC's findings as excessively narrow, examining how the team arrived at their conclusions provides an instructive lesson about the powerful ways conceptual frameworks shape scientific inquiry and the unexpected ways data can be reinterpreted in different problem contexts. (Am J Public Health. 2019;109:1548-1556. doi: 10.2105/AJPH.2019.305260).