ABSTRACT
It is estimated that between 60,000 and 70,000 industrial and commercial chemicals are currently in use in North America, with the possibility of more coming on-stream every day. Only about 3500 of these have been studied sufficiently to conduct any sort of risk assessment regarding human health, and such studies characteristically use only one route of administration (portal of entry). Approximately 600 chemicals are currently judged to constitute a significant potential risk to human health, either because of their toxicity or because they are manufactured in such quantities that there is likely to be a high level in the environment. The public seems unwilling to give up the advantages accruing from such chemicals (plastics, pesticides, petroleum fuels, etc.) but is also increasingly vociferous in its demands to be protected from any adverse effects arising from their use. The environmental damage caused by some of these agents is becoming more and more evident and indeed this may be the real danger facing humankind. Nevertheless, legislators and regulators are faced with the task of making decisions regarding safe limits for thousands of chemicals, often on the basis of very limited data and in the face of pressure from consumer groups, environmental activists, and industry lobbies.
