In human milk the far-reaching effects of toxic exposure are made frighteningly clear. We know that carcinogens can travel from mother to infant in her breast milk and this is not a new medical story. Scientists first discovered that human milk was contaminated with DDT over fifty years ago. A couple of decades later, in 1975, the largest survey of milk of American women was conducted by the U.S. Environmental Protection Agency. The study took samples from more than 1,000 women and analyzed them for several pesticides all of which the EPA describes as 'probable carcinogens' in humans. The results: DDT was present in 100% of the samples; PCBs were in 99% of the samples; and dieldrin was present in 83% of the samples. The FDA measures the amount of toxins in store-bought milk, and when too much of a toxin exists in proportion to the amount of milk, the milk is said to exceed the 'action level.' The FDA is then authorized to remove this milk from the shelves. In 1980, scientists headed by Walter J. Rogan, measured the typical levels of pollutants in breast milk and compared them to the FDA action levels. For three of the four pesticides- heptachlor, epoxide, PCBs, and DDT-the typical range exceeded the FDA levels. Their findings were published in the New England Journal of Medicine.