This whole notion of a "safe" dose of poison is outdated. Our environment is already overloaded with pollution and any additional amount is unacceptable. The entire "science" of risk assessment fails to account for the complexity of systems and tends to look at one chemical at a time and how it affects healthy adult white males with cancer deaths. It doesn't tend to account for women, children, fetuses, the elderly, those with compromised immune systems, the multiple/additive/cumulative/synergistic effects of exposure to many pollutants, or the number of people who survive cancer or suffer non-cancer effects. There is no science that can handle the complexity of dumping 90,000+ chemicals into the environment and understanding all of the impacts.
In effect, risk assessment is merely a "death assessment" where bureaucrats gets to decide how much of each poison the public can acceptably be exposed to -- usually based on a standard of accepting an additional one in a million deaths from cancer for each permitted exposure to each chemical. As Dr. John Gofman once stated about nuclear power: "Nuclear power is mass, random, premeditated murder." The same could be said of most chemical exposures that are permitted by government-determined "safe" levels based on risk assessments.
Rather than rely on this outdated and unscientific method to control exposure, decisions need to be made through community-based needs assessments and alternatives assessments, where the affected populations can take part in a democratic decision-making process on whether proposed pollution sources are necessary in the first place and whether there are safer alternatives that can be employed. The current risk assessment approach assumes that corporations have a right to expose the public to pollution and that it's just a matter of ensuring that they stay within certain "safe" limits.
A former director of the U.S. Environmental Protection Agency once said:
"We should remember that risk assessment can be likened to the captured spy: if you torture it long enough, it will tell you anything you want to know"
The first 7-9 of these articles below mention alternatives assessments. The rest are issues critical of risk assessment. All articles are issues of RACHEL's Environment & Health Weekly.
http://www.ejnet.org/ej/riskassessment.html