but the fact remains, with the hundreds of thousands of new compounds we introduce into the environment, at least some of them are bound to be dangerous, if not downright deadly. Most of them have no analog in nature, living things have never been exposed to them and have evolved no resistance or defense to them. And even more dangerous than those which are immediately lethal are those who might have a long-term, cumulative effect. Even different, benign, substances might have a synergistic effect in combination, or when modified or degraded by the environment. And there are as many mechanisms in nature which tend to concentrate these substances as those which tend to dilute them.

And who can guess how they will affect us, or the environment? DDT in minute doses is harmless to humans but lethal to insect nervous systems. But who would have guessed those same tiny doses could cause cancer in mammals or attack the formation of egg shells in birds? And who would have guessed that even proper use was self-defeating, by breeding resistance in pests and by wiping out natural predators? We simply don't know what the hell we're doing.

We cannot afford to rely on the free market, or the good will of the manufacturers, to monitor the effects of these compounds and sound the alarm when we guess wrong. And the burden of proof regarding toxicity should not fall entirely on the victims, it should most heavily affect those who profit by selling these substances. As LBJ once put it, "Don't piss in the soup, we've all got to eat."