Good morning. What an honor to be here. I know that whenever a speaker is flown across state lines and crowds are assembled, a lot of work has to go on behind the scenes to make that happen. And this also gives me a chance to thank Teresa Heinz for her amazing leadership on the issues that are the nearest and dearest to my heart, and are important to all of our children. Thank you so much.

So I spent the rest of that afternoon conducting interviews. My first call was to the head of the American Bat Association, a man who happens to be a fan of one of my books, so he called me back right away. I wanted to ask him about this whole notion of undetected bat bites: reality or myth? Tom said that most mammologists consider it a myth, and a dangerous one at that, because it contributes to the bad image that bats have in the public imagination as vicious, sneaky, disease-carrying vermin. The big brown bat in particular, he went on to say, is especially unlikely to leave a bite that s undetectable. They're not called big for no reason. That conversation was pretty reassuring.

Next, I interviewed my daughter. Faith said that she and her brother never actually even saw the bat. They heard it chirping inside the heating register and then came to get me. Now I was feeling more reassured. Maybe I didn't need to put them through the shots after all.

Next, I interviewed my son. His story was nearly identical to his sister's, including the part about how they came to get me as soon as they heard the chirping. But just as I was about to heave a sigh of relief, Elijah added another sentence to his story: And then, Mama, the bat flew around the room and landed on my hand. I waited a few hours. I interviewed him again. Same story. But this time he added another sentence to the end: And then, Mama, the bat flew around the room and landed on my hand. And it was carrying a tiny gun.  My son just turned four. It was then I understood why the CDC considers the bat reports of young children to be unreliable.

But I started wondering if the flying around the room part of the story might be true. Could my older child have left out that part because she feared she would have to have shots if she admitted to contact with the bat? I was pretty sure that she wouldn't do that. Could I really account for the origin of each and every scratch and scrape on my kids hands and arms? I was actually reasonably sure that I could. But in the process of doing all this deductive logic, I kept bumping up against two twin pillars of certainty: the 100 percent fatality rate of rabies, a viral disease that is completely irreversible once symptoms begin; and the 100 percent protection offered by the vaccine. So in spite of the fact that I intellectually sided with the mammologist on the issue of undetected bat bites, and intuitively sided with my 7-year-old and her narration of the evening s events, I decided to act in accordance with the precautionary protocol advocated by the Centers for Disease Control. So last Friday, my kids and I finished a month-long series of rabies shots.

Let me now contrast that recent interaction with my local public health department with another. Ten years ago I left Boston, where I had just finished a year-long fellowship at Harvard- Radcliffe, to move into my sister s basement, back in my old home town in central Illinois, where I had grown up. It was here, as a 20-year-old, where I had been diagnosed with bladder cancer, a disease that I now know had longstanding connections to toxic chemical exposures, particularly waterborne contaminants. So I was returning home as an environmental detective in search of my own ecological roots. I did uncover the presence of known and suspected bladder carcinogens in my home town s public drinking water wells. I also found out a few things about the pesticide plant near my high school, and what went on at the local landfill near the house where I grew up.

So what's the difference here? On the one hand, we have a county health department that s vigorously precautionary about an infectious disease; and on the other, we have one that embraces the toxicological version of Don t ask, don't tell. The difference, biologically speaking, is really not a matter of scientific uncertainty. Yes, there s definite proof that rabies virus causes an incurable form of brain encephalitis. But there s almost as much proof that the dry-cleaning solvent perchlorethylene causes bladder cancer. In fact, there's a brand new report, published right here by U. Mass. Lowell, that highlights that very causal connection. It's called Environmental and Occupational Causes of Cancer, and I recommend it to you highly.

Remember too, there's still plenty of uncertainty surrounding rabies. The presumption that all cases of human rabies that occur in the absence of obvious animal bites should be attributed to an undetected bat bite is a pretty controversial presumption.

So rather, I would argue, the difference is one of disease specificity. Rabies is a specific disease. It s caused by one agent. Cancer or asthma or autism or birth defects or infertility or a learning disability, these are non-specific problems. They are caused by more than one factor, and the intensity and progression of these disorders is undoubtedly aided and abetted by many more.

It s still true that perchlorethylene causes bladder cancer, and the more perchlorethylene that is in the environment, the higher the rate the bladder cancer incidence grows. But the non-specificity of the disease means we can't put names to the victims. If I choose to forego a rabies vaccination and drop dead one month later, after capturing a rabid bat in my house, we all know what killed me. But if I die of a bladder cancer recurrence, we truthfully don't know what killed me bladder carcinogens in my drinking water wells, or not.

But the non-specific nature of many human diseases with environmental links does not leave us helpless in the face of a rising toxic tide. It just means we require a different approach to the problem. And that approach is called the precautionary principle. But before I describe it further, let me first detail for you a brief history of our current regulatory system.

About 500 years ago, a medieval physician named Paracelsus coined the phrase the dose makes the poison. His famous pronouncement was based on observations of his syphilis patients, whom he was trying to cure with mercury, which turns out not to be a terribly curative treatment. But the doctor did correctly notice that if you give patients too high of a dose, it killed them outright. Thus, The dose makes the poison.

This idea went on to become a paradigm of modern toxicology, and it still undergirds our entire regulatory system for toxic chemicals. So that when we discover through careful study that a chemical substance is inherently toxic, rather than banning it outright, which we've only done a handful of times, typically we go to work determining so-called safe threshold levels for exposure.

These are sometimes called tolerance levels or maximum contaminant limits. And then we allow these chemicals to be produced, used, and disposed of, all the while policing the results. So we set up an elaborate monitoring system that measures levels of toxic chemicals in everything from applesauce to lake sediment bottoms. Methyl mercury is allowed in canned tuna fish at so many parts per million, the weed killer atrazine is allowed in tap water at so many parts per billion, and so on. Speaking very broadly, our toxic monitoring system is supposed to ensure that the concentration of each and every toxic chemical does not exceed its threshold level, above which risks to human health are considered to be more than negligible.

But the environmental science of the past couple of decades is really mounting an important challenge to that old regulatory model based on risk assessment. It turns out that it's far more than dose alone that makes the poison. To name a couple of others, it s the mixture of chemicals that also makes the poison. It's the timing of exposure that also makes the poison. And it's the underlying genetic susceptibility of the exposed person that also makes the poison. And I know this is something that Lovell Jones will talk more about to you later this morning, so I'll leave that topic to him, but only to say that I, as a 20-year-old diagnosed with bladder cancer, was a full 50 years younger than the average 70-year-old who's diagnosed with bladder cancer.

Now let's examine the other two a little more closely. The topic of chemical mixtures, of course, is the title of our conference today. Are We Living in a Chemical Stew? And the answer of course is an unequivocal yes. There's no controversy here in the scientific community about that. If you yourself still have doubts about it, consider consulting the website www.scorecard.org. Scorecard. This gives you access to the inventory of toxic chemical releases for your hometown zip code. Scorecard.org. Examining the list of toxic chemicals in your own home community, if nothing else, is an interesting spiritual exercise.

In fact, we could even reverse the subject and object of the conference title question. The answer would still be yes. Is a Chemical Stew Living Inside Us? We know our bodies contain hundreds of toxic chemicals. According to the Centers for Disease Control, the body of any one of us Americans contains about 13 different pesticides at any given moment. As you heard from

Teresa Heinz, we now know that umbilical cord blood contains stain removers, plasticizers, and flame retardants. We know the urine of schoolchildren runs with wood preservatives and lawn chemicals. We've found rocket fuel in breast milk. We've found the products of garbage incineration in amniotic fluid. If we live in a city, our exhaled breath contains dry-cleaning fluids and gasoline vapors. If we grew up in an old house, our skeleton contains lead. If we eat fish, our hair contains mercury. We are literally inscribed by a lifetime of chemical exposures. Our toxic body burdens are our environmental autobiography.

Timing also makes the poison, as we have said. All of us in this room have something called the blood-brain barrier. It s working pretty well right now to keep any neurological poison that might be cycling around in your bloodstream let s say, a trace amount of insecticide from the breakfast you consume this morning it keeps it from entering the gray matter of your brain, where it could do some real damage. But none of us developed that blood-brain barrier until we were 6 months old. So anyone younger than 6 months, infants, are missing an entire suit of armor that the rest of us have to protect our brains. Thus infants are exquisitely vulnerable to very tiny, vanishingly small amounts of neurological poisons, far disproportionate to dose alone. So infancy is a time of extreme vulnerability, where safe threshold levels generated for adults may not apply.

And I know you'll be hearing more about this, this morning, from Dr. Lynn Goldman. And there are other windows of vulnerability we all pass through in our lifetimes, as well.

Adolescence is another one. For us women, this is a time when our breast buds are just forming. The breast is undergoing rapid mitotic cell division, and is thought to be exquisitely sensitive to breast carcinogens at this point. And you'll be hearing later this morning from Michele Marcus about the time of puberty and the vulnerabilities associated with that.

Old age is another window of vulnerability. There s much research interest now in understanding environmental links, for example, to late life dementing illnesses such as Parkinson's and Alzheimer's.

Now, in contrast to a risk assessment based regulatory approach that ignores these human rights issues, and approaches the question of toxic chemicals with this simple-minded question, What is the maximum amount of toxic pollution that we can tolerate, the precautionary principle is an entirely different frame of human decision making. In contrast, it asks: What can we do to prevent harm? The precautionary principle has its origins in Germany, when researchers felt ethically compelled to try and halt the ongoing death of its forests from acid rain before all the details about the role of individual air pollutants had been worked out. This was in the 1970's.

The concern was that if nothing were done until scientific certainty was attained, a pipeline of unstoppable consequences would have been constructed, that would have resulted in the mass death and extinction of the forests and the communities they supported.

This idea, that we should act to forestall harm, has since spread to the United States. And in 1998, a lot of researchers and activists gathered in Wisconsin at a remarkable gathering called the Wingspread Conference, where we attempted to actually define the precautionary principle as a tool to guide policy making. I think my own presence at that conference will be something at the end of my life I'll be able to tell my children, I was part of making that history. In fact, I spent a lot of that weekend in the bathroom, throwing up, because I was pregnant with one of my children at the time and was highly nauseous. But I was there. And here's the definition that we came up with, that is now in wide use: When an activity raises threats of harm to human health or the environment, precautionary measures should be taken, even if some cause-and-effect relationships are not fully established scientifically.

I'll just say a couple more things about the precautionary principle, and then I'm going to close by reading a couple paragraphs from my last book.

Precautionary principle has four basic elements. The first one is that people have a duty to respond to early warnings; that action must be taken before harm occurs. Now, this doesn't mean that the precautionary principle is not science-based. It just means that the trigger for action is moved up. The science goes on, but we get people out of harm's way in the meantime. Irving Selikoff was an asbestos researcher who dutifully published all kinds of work bout the dangers of asbestos as it was affecting workers in Libby, Montana, the site of a big asbestos mine. On his deathbed, he expressed his regret that he didn't stop publishing and start doing activism earlier.

He said this: I could have saved a lot of those boys instead of waiting. I don't want to say that at the end of my life. And that's one of the reasons the precautionary principle, I think, offers us so much hope.

A second element of the precautionary principle is that the burden of proof is shifted off of our shoulders, the public, who under the current system has to prove harm, and onto the shoulders or the proponents of whatever the activity is, who under the precautionary principle must demonstrate safety. This is a cornerstone of the new toxics policy of the European Union, the so-called REACH proposal. And as it begins to alter the way we look at the safety of chemicals, and as the European Union grows as a marketplace, it may profoundly alter the global marketing of different chemicals as well. In fact, it s already borne fruit. In Europe, cosmetics companies have been compelled to reformulate cosmetics, eliminating chemicals known to cause cancer and birth defects. And here in the US, a group of nonprofit organizations have joined together to form the Campaign for Safe Cosmetics, to ask for something similar to go on here. In California, I'm pleased to report, the Safe Cosmetics Act has been passed and on October 7 was signed into law by Governor Schwartzenegger. This will compel cosmetic manufacturers in California to disclose any ingredient that causes cancer or birth defects. And I think, as goes California, so goes the nation. So we need to look at this and urge similar reforms in all of our states.

A third element of the precautionary principle is that it requires that we explore alternatives to whatever the toxic substances or the toxic activity is. And when the precautionary principle was applied this way in Canada, it had amazing results. The Canadians, in 70 different municipalities, have decided to ban the cosmetic use of pesticides. So you cannot any longer use pesticides on lawns or gardens simply to improve their appearance. Because when the Canadians looked at the data linking lawn chemicals with pediatric cancers in children, although there wasn't definitive proof, there were troubling signs of harm. So they immediately sought out an alternative to using lawn chemicals to control pests and weeds, and have adopted organic pest control alternatives, which are now the norm. So if you feel like you can t do that, then you have to make your case that you have to use a toxic chemical before some kind of board of commissioners. So the default plan is that you don't use the toxic, you use the nontoxic alternative, and you only turn to the toxic way of doing things if there's no other way to get the job done. So that's an example of precaution in action in Canada.

Fourth, the precautionary principle requires democratic participation. The idea is to increase public participation in decision making. And here we've seen great strides in the city of San Francisco, which has adopted the precautionary principle for all of its purchasing decisions.

And in so doing, the public has been brought into the process, and affected communities are sitting down at the table and making those decisions. So precautionary principle actually improves the whole democratic process.

ProtectingOurHealth.org.

Now, what I like best about the precautionary principle is its directive that we have an obligation to protect those who can t protect themselves, namely, infants and children. Even as we continue to build our own scientific case for action, we keep children out of harm s way, first and foremost. And in that sense, the precautionary principle combines the conservatism of science, which sets the bar for proof very high, with the conservatism of being a parent, which strives to keep our children out of harm s way whenever a situation seems remotely dangerous. I wish I could inoculate my children against the effects of environmental contamination in the same way I can inoculate them against the ravages of rabies. But since we can t, we have the precautionary principle.

Thank you.

 *Portions of the transcript were edited or shortened for readability.