Research at the National Library of Medicine of the National Institutes of Health brought Carson into contact with medical researchers investigating the gamut of cancer-causing chemicals. Of particular significance was the work of National Cancer Institute researcher and founding director of the environmental cancer section Wilhelm Hueper, who classified many pesticides as carcinogens. Carson and her research assistant Jeanne Davis, with the help of NIH librarian Dorothy Algire, found evidence to support the pesticide-cancer connection; to Carson the evidence for the toxicity of a wide array of synthetic pesticides was clear-cut, though such conclusions were very controversial beyond the small community of scientists studying pesticide carcinogenesis.