Calculating Risks? The Spatial and Political Dimensions of Hazardous Waste Policy.

• Author: Porter, Richard C.
• Position: Review

By James T. Hamilton and W. Kip Viscusi.

Cambridge, MA: MIT Press, 1999. Pp. xi, 326. $37.50.

The Environmental Protection Agency (EPA) perceives its mandate as the protection of every American from every risk that is due to past ill-advised disposal of toxic wastes. Trying to achieve that impossible task, and on a limited budget, leads to compromises that are far from cost-effective. As a result of these compromises, "95% of the expenditures at Superfund sites are devoted to eliminating only 0.5% of the cancer risk" (p. 242). That is the bottom-line message of this important book.

The major EPA error is in its calculations of cancer risk and exposure to that risk. Hence the title. (The subtitle is misleading: There is little about space or politics in the book, and it has nothing to say about policy concerning the current generation and treatment of hazardous waste.) Hamilton and Viscusi look carefully at a sample of 150 Superfund sites and find that the EPA regularly overstates the cancer risks and then remediates the sites without proper concern for the number of people affected by those risks.

Chapters 2 through 5 contain the core of their charge of cost-ineffectiveness. In Chapter 2, they review the EPA approach to risk. The EPA lists all the possible "pathways" (e.g., residential ingestion by drinking polluted groundwater accounts for one-fourth of the pathways) by which people may be affected, now or in the future. The EPA then somehow adds the various pathway cancer risks. The authors do not tell us how, but they do state that in one case the EPA estimate of the total probability that a person contracts cancer from contact with a site is 5.1 (p. 32). These pathways involve future hypothetical populations as well as current residents, and the EPA assumes that people would flock to the area even if it were not remediated. Only 18 of the authors' sample of 150 sites have any current population at the site (p. 50). The authors point out that future risks should at least be discounted, if not prevented by zoning restrictions or toxic containment. They do not consider a third possibility: Postponing remediation until an actual population appears and becomes at risk.

The authors are not building just another dump-on-Superfund case. They note that on many Superfund pathways, the individual lifetime cancer probability is greater than 0.01, and sometimes the probability is extremely high. Under EPA estimates, albeit conservative, 652 cancers could be expected to occur if one California site had not been remediated.

In Chapter 3, the authors look more carefully at the EPA's risk estimates. Not only does the EPA simply add various pathway risks, but it overstates them by making a...