Draining the industrial heartland of America, Ol' Man River carries a massive load of industrial and municipal wastes to the sea. New Orleans draws its drinking water from the Mississippi, and so its residents have for decades complained of the city's off-color, off-taste water. For decades, scientists have documented unusually high gastrointestinal and urinary tract cancer rates in New Orleans.¹ More than 10 years ago, medical scientists began to document an association between environmental contaminants and cancer.² In November 1974, the Environmental Defense Fund (EDF) demonstrated a statistically significant correlation between the organic chemicals in New Orleans water and its residents' abnormally high cancer rates. The same month, the Environmental Protection Agency (EPA) reported identifying 66 trace organics in New Orleans water. In December, Congress reacted by passing the Safe Drinking Water Act, which required the EPA Administrator to establish primary drinking water regulations which would set limits on all "contaminants which may adversely affect the public health,"³ and called on the states to enforce the new standards.

In March 1975, EPA issued proposed interim⁴ primary drinking water regulations which included limitations on organic chemicals as a group. In December, however, when it issued its final interim standards,⁵ the standard limiting organics was deleted. In its place, EPA issued new regulations, effective immediately, for special monitoring of these substances in 100 representative water supplies.