Regulating Environmental Hazards
People seek answers to seemingly simple questions: Is the water safe to drink? Is there a safe level of radiation? But usually there is not a simple answer to such questions. For example, what is the safe speed of a car? A car travelling at only 1 mile an hour can kill a person by, say, pinning him to a wall. So we have to say that no driving speed—except, perhaps, zero—is absolutely safe. But in practice we do not strive for absolutely safe auto travel; we are willing to sacrifice some degree of safety for such other benefits as faster travel. Therefore, we usually think of a “safe” speed in such “practical” terms as 30 miles an hour on a residential
street and 65 miles an hour on an interstate highway.
There seems to be a general reluctance to discuss “practical” safe levels for environmental hazards. The resulting debate about the regulation of environmental hazards is therefore unnecessarily acrimonious and inconsistent. Industrial chemicals that are toxic or suspected to be toxic garner more attention that toxic chemicals from natural sources; radiation from nuclear power plants garners more attention than radiation from natural sources. But a hazard is a hazard, regardless of its type. To the extent that the public demands regulation of environmental hazards, the regulation ought to be consistent with the regulation of other hazards and based on scientific evidence.
I begin with a new way of thinking about the exposure of populations to environmental hazards, then describe the relationship between exposure to such hazards and their effects on health. That leads me to an outline of alternative standards for limiting exposure to hazards. I conclude by suggesting a standard that could do much to make environmental regulation less controversial and more effective.