Before she wrote Silent Spring, Rachel Carson was a biologist for the Fish & Wildlife Service, beginning in 1936, and she wrote about issues relating to water contamination for The Baltimore Sun and The Atlantic Monthly. During the World War II years, criticizing chemical companies was considered a short step away from treason, but she continued to write books and articles on the subject. After the war, she criticized the manufacture and effects of DDT, a powerful and effective pesticide that caused damage to animals up the food chain from their intended target insects. In the mid-late 1950s she opposed some of the pesticide programs that used synthetic pesticides to eradicate, for example, the Gypsy Moth. Environmentalism and conservationism were not yet mainstream causes in the United States, and chemical companies made a great effort to discredit her.
In 1957, Carson published a letter in The Washington Post attributing bird die-offs to the overuse of DDT and other pesticides. This coincided with the 1957 "cranberry scandal" where cranberries had high levels of the weed killer aminotriazole, a chemical known to cause cancer in lab rats. Cranberries were taken off the shelves that year and for the next two years as well. By the time they were being sold again, Carson had published her book Silent Spring, a very popular best-seller, and the environmental movement entered the American mainstream.