One of the few things on which almost all economists fully agree is that freetrade is a good thing. It is now more than 200 years since Adam Smith andDavid Ricardo first formulated the theory of comparative advantage and showed that citizens of a region will improve their lot by specializing in doing what they do best and trading for what they do less well. At first glance, there appears to be no reason for treating waste any differently. Waste, of course, is a “bad,” not a “good,” and hence a region has to pay to get another region to take its waste “exports” off its hands. But that does not affect the argument. Regions that dispose of waste well can specialize in waste disposal and use the proceeds to import the things they do less well. One purpose of this chapter is to ask why many people who normally think trade is a good thing want to make an exception of waste. (Of course, people who think free trade is a bad thing are perfectly consistent in their opposition to trade in waste products.)

On a more practical level, it is essential that all waste be traded, in the sense that it must be moved from the place where it is generated-usually a place of high population density-to a place where it is less harmful to human health and the environment. Perhaps there was a time when it was sufficient that each household dumped its own slops over the city walls, but no longer. Aesthetics, scale economies, and cheap transport have made more distant disposal feasible and desirable. Transporting waste is trading waste. All waste is traded.