ment does nothing and another where the government tries to legislate such substances out of existence. There we also discuss actual federal toxic substance policy, which lies, as we might expect, between these two extremes. In the third section, we point out the shortcomings of current federal policy, some of which are easily correctable while others are less so. There we make specific suggestions for policy reform.
Mankind's acute, or immediate, vulnerability to certain substances is a matter of historical record. We know, for example, that Socrates died of hemlock poisoning and that the Borgias routinely dispatched their enemies with lethal mixtures. Such acute effects arise from accidental exposures to less well-known "poisons," as well. For example, more than 4,000 citizens of London died from an extended period of severe air pollution there in 1952. Fortunately, our knowledge of these acute effects continues to grow. Recent studies have linked temporal variations in air pollution within a metropolitan area to acute ophthalmological and other health problems.2
However, our knowledge of the chronic, or long-term, adverse effects of exposures to toxic substances is much less well developed. This is not at all difficult to explain. Latency and uncertainty make chronic toxic substances difficult to recognize and control. By latency we mean the period between exposure to a toxic substance and the manifestation of its effect. By uncertainty we mean our imperfect knowledge of the identity of toxic substances and the way in which they eventually affect health. These problems are discussed at length later in the chapter.
A number of the toxic substances discussed in this chapter are transmitted through air or water. Several were mentioned in chapters 2 and 3. In fundamental ways they often differ from traditional air and water pollutants, and their effects are sufficiently severe to warrant additional discussion. A number of these substances do not imperil their victims through the air and water to which we are all exposed but rather through occupational or voluntary exposures. For this reason, too, the subject of chronically toxic substances merits separate attention.
Two factors account for the increased attention being given toxic substances by Congress and federal administrative agencies. The first is the sheer volume of publicity such substances now receive. The current con-____________________