Hazardous wastes pose a substantial threat to public health and the environ-
ment. They are generated as raw materials are extracted, refined, processed,
and applied to the production of useful goods. When hazardous wastes are
disposed of improperly, they contaminate soil, air, surface water, and ground
water and threaten the well-being of humans and other organisms.

Information on generation, disposal, contamination, and risk is integral to
the regulatory process. Knowledge of the nature and extent of potential dam-
ages creates a demand for legislative action and shapes the regulatory response.
At the same time, implementation results in the gathering of additional
information that alters perceptions of the problem and evaluations of the
regulatory response. Agencies gather information to fulfill legal mandates and
to write the rules that give specificity to the law. The regulated and environ-
mental communities gather information to oversee, evaluate, and critique law
and its implementation. Despite, or perhaps because of, the centrality of
information to the regulatory process, substantial uncertainty surrounds much
important data. Uncertainty emerges from the limited ability of scientists and
engineers to determine the contents of hazardous waste sites, to identify the
pathways of contamination, and to gauge the risks posed to public health and
the environment. Uncertainty is enhanced by the political environment
within which data are generated and interpreted. With billions of dollars and
millions of lives at stake, advocates and opponents of regulation choose and
interpret data to give force to their arguments.

While the dangers associated with hazardous waste have been acknowledged
for centuries, the threat posed to the United States is of relatively recent origin.
It has followed upon the industrial revolution of the nineteenth century and
the chemical revolution of the early twentieth century. Despite a century of

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