Amaranth, the food color additive popularly known as Red No. 2¹ was one of the first chemical compounds to receive regulatory approval under the Pure Food and Drug Law of 1906,² the original federal food additive legislation. For nearly 70 years, the color was widely used to create or brighten the red, purple, brown and white color of foods, drugs and cosmetics. Then, in early 1976, following literally decades of short- and long-term tests of the chemical, the Food and Drug Administration (FDA) abruptly ordered Red No. 2 off the market,³ and the Court of Appeals for the D.C. Circuit unanimously upheld this ban against an industry challenge.⁴

The case of Red No. 2 demonstrates growing sophistication over the last half-century in administrative, congressional and judicial responses to the subtle health threats posed by synthetic organic chemicals. The color's testing history—initial acceptance based on short-term acute toxicity tests, lengthy re-evaluation with long-term animal feeding tests, and discovery of cancer-causing (carcinogenic) potential through the use of mathematical statistics—reflects both the growing rigor of toxicological research techniques and the difficulty of discovering widely-used chemicals' risks. The evolution of the legal matrix—initial imposition of the statutory burden of proof respecting food additive safety on the government and then its transfer to a substance's proponent—typifies growing congressional sensitivity to the need to anticipate subtle health effects of chemicals. Finally, the judicial response—firm support for administrative intervention to protect the public health despite very limited evidence of harm and palpable injury to the industry—follows a short but swiftly lengthening line of sympathetic judicial reactions to precautionary regulatory actions in the environmental/public health field.