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University at Albany Center for Public Health Preparedness

ASSESSING CHEMICAL EXPOSURE: A DIFFERENT APPROACH

Original Satellite Broadcast: 1/6/05

MODERATOR: Hello, and welcome to the University at Albany Center for Public Health Grand Round Series. I'm Peter Slocum, and I'll be your moderator today. Before we begin, I'd like to remind you to please take a moment after the broadcast to fill out your evaluations. Your feedback is very helpful in the development of future programs. I'd like also to remind you that we'll be taking questions later in the hour. The toll-free number is 1-800-452-0662. You may also fax your questions to us at 518-426-0696.

Today's program is on Assessing Chemical Exposure: A Different Approach, with Dr. George Eadon, Director of the Division of Environmental Disease Prevention at the Wadsworth Center at the New York State Department of Health. Thank you for joining us today.

EADON, G.: Thank you, Peter.

MODERATOR: Well, let's talk a little bit at the beginning here about the relationship between chemical exposure detection and the terrorism threats, particularly from chemical weapons or agents. Specifically, what do we want to focus on today?

EADON, G.: Well, I'm going to try to cover three broad topics in my limited time. First, a general introduction to chemical terrorism with some discussion of the specific types of incidents that we in public health might be called upon to respond to. Secondly, a very brief discussion of the classes of agent and some mention of what their mechanism of action is. And finally, the longest part of my talk will be about the public health response to a chemical terrorist incident. And since I represent the laboratory, the emphasis is going to be on those aspects of the public health response that depend on laboratory data.

MODERATOR: Now from the point of view of terrorists, they have obviously a range of weapons, if you will, in the chemical arsenals. What are the pros and cons for them of using different approaches?

EADON, G.: Right. Well, as my next slide shows, there are five commonly discussed approaches to producing terror. I'm not going to talk very much about four of them. I'll just mention biological. I'm not going to say anything about it because you've talked about that previously in this program. The conventional box represents the use of explosives and bullets. And that's by far the most widely used approach. The FBI did a survey of all domestic terrorist incidents over the last 20 years and found out that more than 99 percent of the threats and incidents, in fact, involve conventional agents.

Among the weapons of mass destruction, the nuclear box represents the possibility of an atomic bomb being detonated in an urban area. That's the classic low probability, high consequence event. The radiological box is something quite different. What we're talking about there is the dirty bomb idea. That someone might use an explosive to spread radioactivity over a broad urban area, thus potentially denying the use of tens of square miles for years or decades.

MODERATOR: I see.

EADON, G.: But what we're really here to talk about is chemical.

MODERATOR: Uh-huh (affirmative).

EADON, G.: Chemicals are considered to be a high probability motive attack as well. And it's not hard to see why. We live in a modern, industrial society. And one of the costs of maintaining that society is that we more or less have agreed that we're going to allow chemical plants, manufacturing facilities, and petroleum refineries to store and use large quantities of toxic chemicals on their sites. And additionally, we allow toxic chemicals to be shipped freely around the country on our highways and our railways.

It's also not particularly difficult to dream up and execute a plan that would result in dispersing these toxic chemicals into a populated area.

MODERATOR: Right.

EADON, G.: If that isn't convincing enough in and of itself, there is a survey that the Monterey Institute did of international terrorism over the last 40 years. And they concluded that the chemical incidents were more than half of the incidents that involved weapons of mass destruction. Biologics came in a somewhat distance second in that ranking. So, if history is any guide, we should be ready for a chemical attack.

MODERATOR: Okay. Well given that, let's talk about some of the specific common chemicals that are of most concern to you as you think about bioterrorism threats.

EADON, G.: Well, when I talk about the choice of chemicals, I find it useful to think about them in terms of two main classes. And the first is the toxic industrial chemicals. And these are chemicals which have important uses in manufacturing processes and just happen to be toxic. But the other class of chemicals we need to worry about are the chemical warfare agents. These perform no social useful purpose. They've simply been manufactured and designed and optimized to be very good at disabling and killing people. And as a consequence, there might be ten or a hundred or a thousand times more toxic per gram than these toxic industrial chemicals.

But let's talk about them first. Ah, my next slide lists five toxic industrial chemicals that might conceivably be involved in a terrorist attack. I want to make the point that this list is illustrative not exhaustive.

MODERATOR: Uh-huh (affirmative). Right.

EADON, G.: In fact, there's something like 80 thousand chemicals that have current commercial uses in the world today. And something like three thousand of them have been made in quantities in excess of a million pounds. And a lot of them are toxic. And so a terrorist has essentially an infinite menu of chemicals it can actually choose. These are some of the ones that are particularly toxic. Chlorine and phosgene, in fact, were used as chemical warfare agents during the First World War.

MODERATOR: Right. And then let's focus a little on methyl isocyanide as an agent in the tragic experience with that agent in India.

EADON, G.: Well, methyl isocyanide is a little bit of a ringer in this list, because it isn't used in this country anymore. And, as you mentioned, the Bhopal incident in India is one of the reasons why. This of course was not a terrorist attack. It was either an industrial accident or employee sabotage, depending on who you believe. But I think it's interesting, because it provides a good upper limit to what a terrorist attack on a chemical plant or a tanker might in fact do. And we can see from the slide that about 11 thousand people were permanently disabled. About 38 hundred were dead. And the only other point I'll make about that slide since I know you've talked about the incident in previous shows is that the tank that contained the methyl isocyanide contained about 40 tons of material. You could possibly squeeze that into one of those large tank trucks that whizzed by you on your way to work this morning.

MODERATOR: Really?

EADON, G.: You could certainly fit it in a railroad tank car.

MODERATOR: So it's not an extraordinary amount in terms of the kind of material that we move around this country today.

EADON, G.: That's correct.

MODERATOR: Right. And as I recall, that incident, if it was employee sabotage, was a relatively simple operation, which triggered the lethal reaction of the chemical.

EADON, G.: Well, the union carbide version of events is that he took a water hose that happened to be nearby and just stuck it in the tank and turned it on.

MODERATOR: Right. And that was enough to --

EADON, G.: That did it.

MODERATOR: Wow. Well, you mentioned before that there's a range of toxicity in different chemicals. I know you have a slide that's very illustrative of that. Do you want to talk a little bit about what types of chemicals are the most toxic here?

EADON, G.: Right. Well, the next slide I won't go into detail about the units on the axis, but the next slide just gives us a graphic illustration of the relative toxicity of some chemicals that we have mentioned or will mention when they are inhaled. And basically all I need to say is that the higher the bar, the more of that material you need to inhale in order to have a 50 percent chance of causing fatality.

And you can see, chlorine, which we in public health ordinarily think of as being a very dangerous chemical, actually requires quite a bit of material to cause that kind of effect.

MODERATOR: That's on the far left there.

EADON, G.: That's on the far left. And the next bar, which somehow didn't get labeled, is phosgene, hydrogen cyanide. And then we start moving to the chemical warfare agents. The fourth bar is mustard agent, which was used during World War I as a chemical warfare agent. And as we get down to those boxes, which you can barely distinguish at the far right-hand side of the slide, those are nerve agents. And you can see that they are a hundred or a thousand times more toxic than these industrial chemicals. And thus, they're more dangerous in many respects.

MODERATOR: Right. And so while they look de minimis on this slide that actually means that they're most toxic.

EADON, G.: That's correct. That's correct.

MODERATOR: Right. Well, looking at these highly toxic agents, what would motivate a terrorist to choose one or the other from their other characteristics?

EADON, G.: Well, from the perspective of a terrorist, the advantage of these chemical warfare agents is that they are useable in relatively small amounts. Instead of talking about a tank car as your reservoir of chemical for an outdoor incident, you might be talking about a 40-gallon tank.

MODERATOR: Right.

EADON, G.: Or it might fit in the gas tank of a large sport utility vehicle.

MODERATOR: Okay.

EADON, G.: If you want to do an indoor incident, you might have enough to do an effective incident I something like thermos bottle. This opens up the possibility of surreptitious use. Basically liberating the agent and then escaping without detection and also makes it easier for you to do a targeted attack without alerting your victims to the fact that they're being attacked, which would make it more effective.

The disadvantage from the perspective of the terrorist is that these agents are much harder to obtain. There are some of these chemicals in the country today, but they're under military control and are being destroyed under international treaty. So you're going to have trouble stealing them. And if you want to make them, I guess how hard they are to obtain depends on who you are. Certain nations can make them easily. Many third-world nations have.

MODERATOR: Uh-huh (affirmative).

EADON, G.: Cults, as we'll see in a second, have successfully made and actually successfully used these chemicals.

MODERATOR: Right.

EADON, G.: And it isn't beyond the bounds of possibility for the individual lunatic who has access to a university chemistry lab at night and is able to order small amounts of innocuous precursor chemicals and put them together into these compounds to make enough to conduct an indoor incident without having been detected I think,

MODERATOR: Has adequate chemical training and knowledge.

EADON, G.: Right. Right.

MODERATOR: Well, we've actually seen some of these agents in use haven't we. As you mentioned with the cult experiences in Japan.

EADON, G.: Right. That's absolutely correct. And I think the most famous incident was the Tokyo subway incident conducted by the Om Shin Rikyo cult in 1995. In this case, three groups of terrorist boarded three separate subway cars carrying plastic bags filled with diluted solution of sarin, which is a nerve agent. And they put the bags on the floor of the subway cars and punctured them with an umbrella and walked out of the car. And the outcome of that was about 12 people were killed and five thousand were injured.

Now it's worth saying that that was a pretty punk effort at an attack for several reasons. One was that the sarin was very dilute in its container as best as anyone can make out. And secondly, because sarin is not a gas. It's a liquid. And so by dispersing it on the floor, very little of it was actually introduced into the atmosphere.

MODERATOR: Oh, I see.

EADON, G.: If you really wanted to do this correctly, you'd figure out some way to aerosolize it. So that people would have a higher exposure to it. But nevertheless, 12 people were killed.

MODERATOR: And almost five thousand people went to Tokyo hospitals. Now an awful lot of them were what we call the worried well. Or they were exposed, but they weren't sure how seriously and got to the hospital pretty quickly though on their own. Right?

EADON, G.: Well, that's correct. And that's a good question. As best as the Tokyo medical authorities can make out, about four thousand of those people really had no exposure to the agent. They were the worried well. And as a result of this and actually many other such incidents, when we plan for these events now days, we customarily expect to have about ten times as many people who are worried well versus the number of people who are actually exposed. And that imposes all kinds of problems for medical treatment and triage.

MODERATOR: Yes. In fact, we had an expert in the treatment aspects on this serious earlier who talked about the difficulty of planning hospital emergency room reaction to that very phenomenon and how to do triages to make sure the emergency workers got a chance to treat the people who actually needed the most treatment.

EADON, G.: Yeah. Because the worried well tend to get there first, right? [laughs]

MODERATOR: That's right. [laughs] Okay, having covered the nerve agents and so on, let's talk a little bit about the industrial chemicals and how they might be used in a terrorist situation.

EADON, G.: Well, let's talk about the idea of an overt exposure first. And the obvious approach to an overt attack would be some sort of a blast or leak of a tank or a tank car in a populated area. Another thing that's been discussed widely is introducing the chemical into a ventilation duct of a building. And if you've been looking closely, you know that a lot of effort has been expended to make those ducts more secure among likely target buildings. Releasing it in a closed space is a possibility.

The vehicular releases are interesting. The Om Shin Rikyo cult actually did a vehicular release in an attempt to slow down several judges who were hearing a case against them. They drove a van and parked it in front of their apartment building and stuck an aerosolizer out the roof of the van and released sarin.

MODERATOR: Oh, really?

EADON, G.: Killed a number of people. Seven, I believe. And sufficiently injured the judges and the trial that they were losing was delayed for 18 months. The other vehicular release that we need to worry about is crop dusting. And those of you who remember the 9-11 incident well will recall that the Al-Qaeda group that launched that attack actually were very interested in obtaining access to crop dusting planes. It's not clear whether they were planning a chemical or biological attack. But it certainly would be possible with a plane.

MODERATOR: Right. So as an agent, a vector so to speak, that has some serious potential.

EADON, G.: That's right.

MODERATOR: Well, I would think that introducing a chemical agent into the population, there's more effective if it's covert and not obscure for a couple of different reasons. Right?

EADON, G.: Yeah. That's correct. Now I have to confess that when I think about chemical terrorism attack, the first thought that pops into my mind is the image of the HAZMAT team in their moon suits walking around people lying disabled on the ground. But in some respects, the covert exposures are more frightening and in fact more relevant to public health, because they pose a different set of problems. And probably in a manner of speaking, we in the public health and in the medical community are going to be the first responders to these covert attacks.

And the slide lists some of the possibilities that people have talked about. Basically contaminating food or some medication product or cosmetic with the chemical. The idea of contaminating a surface that many people might touch, like a banister in a subway station stairwell or the possibility of contaminating something like water or natural gas. There are a lot of possible incidents or ways of conducting these attacks. The one I'll talk about as an example is the idea of someone contaminating the food supply with some sort of chronic poison. Some poison that either doesn't exert its effect very quickly, like perhaps carcinogen.

MODERATOR: Right.

EADON, G.: Or some poison that needs to accumulate to a certain level before people begin to become sick. Now the way that would play itself out in our society where food is consumed over a broad geographical area is that one or a few individuals would develop symptoms either because they ate a lot of the food or because they had a genetic susceptibility to the poison. They would go to see their doc, and their physician would probably not identify the agent or not identify the problem. First, he has no reason to think the person's been exposed to a chemical. And secondly, he's certainly never seen that syndrome before.

MODERATOR: Right. Unlike the physician confronted with gastrointestinal distress after the person eats bad hamburger or something.

EADON, G.: That's right. And so individual people would go see the doctors, and it would be quite a while before anyone put together that we were actually dealing with a food poisoning, a chemical food poisoning event. And then once that was revealed, this would pose a great deal of challenge to the public health community. It would be like investigating a food poisoning infectious disease outbreak only worse because there are 88 thousand, or 80 thousand or so possibilities for the chemicals that might be involved. And it's very hard to figure out what's going on.

There haven't been too many intentional incidents that follow this recipe, but there have been a number of accidental ones. And most familiar to those of us in the environmental or public health chemistry arena are the ones that occurred in Asia about 20 years ago where the food supply became contaminated with PCBs and the more toxic thermal degradation products. And in those instances, that's essentially how the incident played out. Many people were exposed long after the first patients were detected, because no one could understand what was causing the exposure.

MODERATOR: Right. And of course, the one that everybody knows about recently is in the Ukraine were a presidential candidate was apparently poisoned with high doses of toxic dioxins, which were recognized very quickly. And it was only a single target apparently rather than a whole population.

EADON, G.: Right. And that was because he received such a massive dose. The symptoms are fairly indicative.

MODERATOR: Right. And of course, we didn't talk about it, but the Tylenol incident that many of us remember here in the United States was an example of using a chemical terrorist attack of some kind in a medicine or a pill jar, which was dispersed rather broadly. We never really learned what happened there.

EADON, G.: Yeah. That's right. That was a little bit different but still relevant to this scenario, because obviously when you found people dead holding a Tylenol bottle, it wasn't too hard to figure out what the cause was.

MODERATOR: Right.

EADON, G.: But if you go back and look at that story, you'll see that actually it wasn't instantly realized what the cause of that illness was either. They weren't immediately withdrawn from circulation after the first deal, the Tylenol capsules.

MODERATOR: Right. Now I understand that you folks in this field classify these chemicals based on their type of -- their mode of action, what they do to us chemically in our bodies.

EADON, G.: Yeah. That's correct. And I just want to go down very cursorily some of the classes of toxicity that we need to be concerned about. First, I'll mention the respiratory irritant gases. And I've listed just a selection of the ones that fall into this category. You can pretty well guess from the title what these things do and how they operate. They're obviously gases. They are respiratory poisons, which means they operate by inhalation. And their function is to irritate the lung.

And the next slide indicates that the reason they irritate the lung is that they are rather a highly reactive chemical. Some of them are strongly acidic. Some of them simply conduct chemical reactions with the constituents of your cells and basically destroy and kill your cells. The results of this are things like pulmonary edema, lung scarring, and ultimately death.

MODERATOR: Let's turn now to blood agents and how they work.

EADON, G.: Well, the blood agent is military terminology. More appropriate toxicological term is the metabolic toxicants, because these all operate by interfering with some metabolic process which is essential to your survival. And again, this slide illustrates a laundry list of possibilities for that particular mode of attack.

MODERATOR: Alright. And to illustrate a little more detail, let's talk about carbon monoxide as one of those, which we're probably most familiar with.

EADON, G.: Well, I chose that one to talk about from that list because it's the number one chemical cause of acute toxic death. It's interesting as a terrorist agent. It's sometimes called the silent killer, because it's an odorless, invisible gas. And at high concentrations, the first symptom of exposure is lack of consciousness. And the way it works it basically is much better at bending to the oxygen carrying hemoglobin molecules in your body than oxygen itself is.

MODERATOR: It crowds out oxygen.

EADON, G.: At very low concentrations, it will crowd out the oxygen. And the cells in your brain will not be getting enough oxygen to continue functioning. You'll pass out, and when you wake up you'll be dead.

MODERATOR: Right. I see. [laughs] And of course, this is a concern in a non-terrorist sense. The utility companies all around our country are very adept at quickly responding to consumer concerns and rushing out the test for the presence of this because of heating systems.

EADON, G.: Yeah. That's correct. Any time you burn something with carbon in it, you're inevitably going to product carbon monoxide. And that's why there are almost a thousand accidental deaths in this country every year due to carbon monoxide.

MODERATOR: Wow. One of those underreported, under realized phenomenon. Let's talk now about another chemical class. That's blister agents - how long have they been around?

EADON, G.: Well, these first came to prominence in World War I where they were used quite effectively as chemical warfare agents. There are three classes of blister agents. The sulfur agents, the nitrogen agents, and lewisite - which actually contains arsenic, as well. It's sort of a double duty poison.

MODERATOR: Okay.

EADON, G.: But the sulfur agents, there are many of them, hundreds of them that have been investigated for military use. They really have. Only in military use. The nitrogen agents are also numerous. And some of them are used in chemotherapy for cancer. They basically prevent cells from dividing, which is one of the root causes of cancer, uncontrolled cell division.

MODERATOR: Right. And these can indeed be lethal in large doses. Right?

EADON, G.: That's right, although the mustards are really --

MODERATOR: World War I they didn't tend to be lethal. Right?

EADON, G.: They're more a disabling agent than a killing agent. What they do is begin to react with the molecules in your skin cells first if you get them on your skin. If you were clever enough to wash the area off immediately after contact, the symptom are fairly minimal. If you don't, you'll develop very ugly and painful blisters. One of the characteristics of this agent, which makes it very feared, is that its symptoms aren't immediately manifested. Typically, you're talking four to 24 hours, depending on how much dermal exposure you actually get, which means that it lends itself to a covert attack - applying it on a surface, for example.

MODERATOR: Right. So you can impact a large number of people without being discovered quickly and the public health people taking action to prevent it from further damage.

EADON, G.: Correct. Uh-huh (affirmative).

MODERATOR: I see. Alright. Should we move onto nerve agents now a little bit?

EADON, G.: Okay. And the nerve agents of course are the most famous class of chemical warfare agent. It's a little hard to talk about how they operate in 30 seconds, but let me just say that your nervous system communicates with other nerve cells, with muscles, or with glands, with target cells by using a chemical messenger. And for the system to work properly, that messenger must be destroyed very quickly after it's released. Because if it isn't destroyed, the target cell keeps thinking it's being signaled to do something. And in order to make this destruction to happen rapidly, we have an enzyme called acetylcholesterase. And the nerve agents are cunningly and cleverly designed to put that enzyme out of action.

MODERATOR: I see.

EADON, G.: And so what happens if you're treated with a nerve agent or -- What happens is that your enzyme becomes poisoned. This messenger accumulates, and your target cells are continually over stimulated, producing --

MODERATOR: Because they're not getting the message to shut off.

EADON, G.: Well, it's like someone's still knocking on the door and telling them to open up.

MODERATOR: Right.

EADON, G.: And they do, but they're not supposed to be doing it. And the results are various, very undesirable medical effects.

MODERATOR: Alright. Let's talk a little bit about the physical properties of these nerve agents, which you say are the most well-known or widely feared.

EADON, G.: Well, the first thing I'd mention about them is that they're not liquids. They're gases. And that means that they need to be dispersed as some sort of an aerosol to be effective. Secondly, solubility in both fat and water. The water solubility means that if you inhale them into your lungs - which is an aqueous environment, they'll quickly wind up in your blood stream. The fat solubility means that if you get them on your skin, they'll quickly be absorbed through your skin and have the same effect. I've listed the names of some of the commonly discussed nerve agents on the slide: tabun, sarin, soman. These are the so-called G agents, which were developed by the Germans -- G stands for German -- around the time of World War II.

MODERATOR: Uh-huh (affirmative). World War I or II?

EADON, G.: II. They weren't used, but they were developed. And then VX, which was developed by the allies in the '50's and is actually a much better agent at killing people.

An investigative chemist could come up with many hundreds of molecules, which would be structurally similar to these and would be useful as nerve agents. But there are only about six of them that are actually made in large quantity by nations.

The other thing I would mention about these agents is that some of the most potent insecticides are within a factor of ten to one hundred as potent as nerve poisons as the less active these agents are. So insecticides could also be used to launch an attack similar to ones using nerve agents, only with larger quantities.

MODERATOR: I see. They'd need larger quantities to be massively effective the way these are.

EADON, G.: That's correct.

MODERATOR: Are there quantities of these agents still stockpiled around the world?

EADON, G.: Well, nerve agents are actually present at eight sites in the United States. We're in the process of actually destroying them right now under international treaty. All acknowledged sites need to be destroyed in the next few years. It's a question as to whether that will actually happen.

MODERATOR: Right. And of course, I think you suggested that a talented chemist could produce some of these without the benefit of the military industrial complex behind him or her. Right?

EADON, G.: That's probably true.

MODERATOR: So if one is exposed to a nerve agent, what actually happens? What are the signs and symptoms? Is it always fatal? That exposure?

EADON, G.: No. Not always. In fact, there's a very well developed pharmacology out there to treat people who are exposed to nerve agents. And in fact, many of the agents needed are stockpiled around the state and around the country.

The symptoms -- I would throw up this slide, because it has a clever pneumonic that enables even me to remember the symptoms of nerve agent exposure. And it's this ‘DUMBELS’ idea. Most of these terms are familiar to you. Myosis corresponds to your pupils contracting to a pinpoint. It's a very useful diagnostic in the field. And again, the others are all representative of the fact that glands or muscles are being over stimulated by the fact that your chemical messenger is not being destroyed by acetyl cholinesterase.

They all exhibit pretty much the same symptoms, because they're all attacking the same enzyme.

MODERATOR: Oh, I see. Alright. So when your enzymes are blocked, this is the kind of things that happens in our bodies in all cases.

EADON, G.: That's right. That's right.

MODERATOR: Alright. So we've covered a number of these agents. Are there other ones that we need to be worried about?

EADON, G.: Well, there certainly are. I'll just mention one other class of agent. It kind of falls in the gray area between biology and chemistry - it's the toxins. These are poisons, which are produced by living organisms. I think last month Dr. Cirino talked with you about the botulinum toxin, which is produced by bacteria. A lot of them are produced by plants and algae. The next slide shows a picture of the castor bean plant, which is the source of ricin, which is a fairly potent toxin. The plant itself is grown for agricultural purposes; it's the source of castor oil. But it's also grown for decorative purposes by gardeners. And there are recipes out there readily available that tell people how to isolate the ricin from the bean using ordinary chemicals in their kitchen. So it's a potential problem for a terrorist attack.

MODERATOR: Now is it something that we have experienced? The castor bean or related toxin attacks?

EADON, G.: There have been such attacks. The most famous was a Bulgarian spy, in essence, who was stabbed in London by an umbrella while he was waiting at the bus stop. And after he died, they did discover that a small amount of ricin had been injected into him by that umbrella stab. And he died within a couple of days with symptoms that were initially diagnosed as being sever pneumonia.

MODERATOR: Oh, I see. But that was an example of someone doing a little home chemistry work to come up with that?

EADON, G.: No. No. That was apparently the Russians attempting to retaliate against this fellow for defecting.

MODERATOR: Oh. I see. Alright. So we've talked a lot about now the characteristics of the agents and the terrorist mindset, or the advantages and disadvantages from their points of view. Let's switch now to our public health response and talk about some of the things that in the case of a chemical agent attack -- what should public health professionals aim to do?

EADON, G.: Right. Well, my next slide, which I borrowed from CDC, lists CDC's public health aims in a chemical event, although it's fair to say these are probably the aims of any health department that's addressing this problem. One goal will be to identify the agent or cause of the illness that's being observed. The first thing everyone thinks of when we talk about this is, "Hey, let's collect a sample and send it to the laboratory." That's probably not the best way to get a quick answer. And in fact, as we'll talk about in a couple of minutes, you're probably going to have a pretty good idea of what we're dealing with based on the clinical syndrome exhibited by the victims.

The second thing you're going to want to do is to determine the temporal and geographical distribution of exposure. How large an area do we need to evacuate and for how long? You're also going to want to determine who's got high and low exposures and evaluate the health implications of those exposures from the point of view of providing medical treatment and epidemiological follow-up. Provide medical and public health guidance and support. And then provide continued surveillance and prevention to avoid the possibility in so far as possible developing long-term health effects.

MODERATOR: So from the point of view of our audience, the public health professionals, these are the main things to keep in mind. Right?

EADON, G.: Well, right. This is a somewhat selective list, because these are lists which really are based, at least to some degree, on laboratory support. And that's really what I'm trying to concentrate on today.

MODERATOR: I see. So in effect, that's the field feeding you and your ability to help them determine what exactly is going on there.

EADON, G.: Right.

MODERATOR: Okay. How does collecting and analyzing samples after a chemical attack or chemical exposure help them meet these goals?

EADON, G.: Well, we can talk about two kinds of samples. And first, let's talk about environmental samples, which correspond to sampling the air or water or wiping a surface and sending it to the laboratory. These are the best samples that are available to identify the chemical agent on the scene. The reason is that a water sample is obviously much less complicated than a urine sample or a blood sample. There are many more interfering compounds in the clinical samples than in environmental samples. And so a laboratory is going to have a much easier time in identifying the agent and is going to do a much better job at actually quantitating the chemical if he gets an environmental sample.

Second purpose is to define the contamination zone. Typically, the evacuation criteria is going to be based on an environmental measurement. What concentration of the chemical in the air requires evacuation, for example? And obviously you're going to get that from an air sample.

MODERATOR: Right. For instance, the nuclear power plant safety planning that's gone on in this country for decades is based on that kind of thing. Do you shelter people? Or do you ask them to evacuate in the area around a nuclear power plant if there's certain exposure coming out of that plant?

EADON, G.: That's right. And then we also want to check for effected decontamination of people and of the scene. And there are recipes out there, but I think in practice you're going to want to check to see that those recipes are working effectively as they're being conducted by your own staff on your particular incident.

And then finally, determine when to allow reentry. Obviously, we want to reoccupy the space. And once again, the reentry criteria are probably going to be expressed in terms of some environmental concentration that's measured in the air or on surfaces.

MODERATOR: As they were in the senate office building, for instance, in the anthrax incidents several years ago. Right?

EADON, G.: Right.

MODERATOR: Alright. What defines a clinical versus environmental sample? And how -- Why is it important?

EADON, G.: Well, a clinical sample for most of our purposes after a chemical terrorism incident corresponds to typically a blood or a urine sample. And they have usage, which are somewhat complimentary to those of the environmental sample.

The first application is to confirm the agent identification. When you measure the chemical in a clinical sample, what you're usually measuring is a metabolite. So it's in some sense an independent assessment of what the person was exposed to from the environmental sample, which is useful to make sure you got it right in the environmental sample.

MODERATOR: Right.

EADON, G.: There are situations in which you can imagine the only way you're going to identify the agent is by looking at a clinical sample. Some of these agents dissipate very rapidly, especially if we're talking about gases. Others of them are going to be destroyed quickly in the environment or destroyed in the process of decontaminating the people in the area. And so it may be that the only way -- the only sample that you're going to get that's useful is one collected from the person, which the person has served as an voluntary sample collector if you'd like.

One of the things that I think we've learned form some of the instances in this state is that when you have a mass casualty event, it's very difficult to get people to collect an environmental sample. The focus is going to be on saving lives, not going out and collecting an environmental sample. So you may well find that it might be hours or days after the event before you actually get that first environmental sample collected.

MODERATOR: I see. So hence, you're going to have a vacuum there, which the clinical sample can help to fill.

EADON, G.: That's correct. Then assistant medical treatment. That also needs a little bit of elaboration. It's very unlikely if you're dealing with an acute fast-acting agent, like let's say a nerve agent that you're going to be able to collect a sample from someone, ship it to remote laboratories in Albany or Atlanta, have that sample processed, and get the result back in time to have very much impact on treating that acute exposure. The guy's either going to be killed or cured long before the number comes back.

MODERATOR: Right.

EADON, G.: The way this data will assist in medical treatment is that first of all it may be useful for addressing the longer term effects of the exposure. Or if it's a slow-acting agent. If it's something that -- If you're talking about affects which may occur after the nerve agent exposure as has been proposed after, for example, the first Persian Gulf War -- this would give you some useful information about who has been exposed and how to treat it. So there are scenarios in which this would assist in medical treatment, but not in the immediate, acute phase of the problem.

MODERATOR: Right. And the separation of the worried sick from the worried well can be useful to a certain extent, but as you say, not immediately.

EADON, G.: Right. You're not going to be able to do that immediately, but obviously in periods of time of a few days or perhaps a week or two you'd be able to eliminate the worried well from the population you're treating and thus more effectively use your limited medical resources.

MODERATOR: Okay. And then in a long-term sense, you have the health effects analysis. Right?

EADON, G.: Right. And this is really one of the most important applications of the clinical sample. The only way you're really going to know how much exposure people have and who's exposed and who's not is by collecting a human sample and measuring that individual person's exposure. And that's really going to be essential into sorting out whether a health effect that's observed a year later was due to the exposure or was due to some other extraneous event.

MODERATOR: Alright. But we can't use just environmental exposure for some of the reasons you talked about to accomplish these goals. But you can talk a little more specifically about the weaknesses of the environmental sample that you get.

EADON, G.: Right. And I'd originally planned to talk a lot more about the utility of biomonitoring versus environmental samples as far as assessing exposure. But I don't really think we have quite enough time. But I just want to make the important point that predicting the level of toxicants in an individual based on environmental monitoring is a very difficult thing to do and includes a great many assumptions.

Just to list a few of them, for example, the idea that one environmental sample perhaps collected somewhat after the incident is representative of each individual's exposure hours before is obviously pretty naïve. We also know that in many instances of chemical contamination, the concentration of a chemical will vary widely just over a short geographic distance. If we're talking about say inhalation, we don't know how much air that person has inhaled. Perhaps he was frightened and breathing rapidly or perhaps he was unconscious. And that's going to affect his respiration rate and the amount of chemical he has taken into his lungs. We don't know how much of the chemical he's taking into his lungs is going to be absorbed and how much is going to be exhaled. That may even vary widely from individual to individual, depending on genetic factors. And we don't know how good that individual is at excreting the chemical and metabolizing it and excreting it versus how good he is at activating it and making it something worse than the initial compounds.

And so those are just a few of the assumptions that there's really no very good way of making. And so what public health people have to do is take wild guesses at these. And they're really not -- They really don't give good estimates of an individual's exposure. The way to do it is to collect a human specimen.

MODERATOR: Right. So if I'm jogging down the road, obviously I'm going to have a lot more exposure than if I'm sitting in the living room reading the newspaper.

EADON, G.: That's correct.

MODERATOR: I mean, because you're inhaling more.

EADON, G.: Yeah.

MODERATOR: Right. Alright. Now biomonitoring. Let's talk a little bit more about that. And it's a relatively new science. Isn't that right? Or application is just beginning to be more of a useful tool?

EADON, G.: Actually I think the first application of biomonitoring in public health was its use to assess lead exposure among children. You know, we want to know which children needed medical treatment for lead exposure. We don't go out and collect a dust sample from the house. We measured the child directly, because we realize that there are too many assumptions involved in that extrapolation.

What's new is that technology and instrumentation have advanced to the point that we can now measure a great many environmental chemicals in the human subject. And so it's a much more broadly applicable way of accessing human exposure to toxic chemicals, whether we're dealing with a terrorist attack as we're discussing here, or whether we're dealing with the day to day business of public health where people are concerned about their exposure to environmental chemicals.

MODERATOR: Alright. Let's switch now to the sort of the institutional relationships here. And what's the CDC's role in responding to chemical terrorism attacks?

EADON, G.: Well, this I need to emphasize. CDC really has, especially the national Center for Environmental Health, one of CDC's centers, and specifically the chemistry lab. Their role is strictly confined to the analysis of human samples, whether we're talking about a chemical terrorism incident or whether we're talking about public health investigation. And if we're talking about environmental samples, which is the other thing that might be relative here, that role is assigned to the United States Environmental Protection Agency. And the expectation is that in a federal investigation or an event that has received federal attention, both of those agencies are going to work together to address the problem.

MODERATOR: Both will be involved then. The split sample -- the activity goes into effect, although it stems from different sources obviously.

EADON, G.: Right.

MODERATOR: Okay.

EADON, G.: Now one thing I want to mention about CDC's role is that in 1999, CDC competitively awarded five grants to state public health laboratories to develop their capacity to measure chemical warfare agents in human specimens. And this I think is unusual in that 1999 was early to do this.

MODERATOR: Right.

EADON, G.: I think, you know, obviously it was before the World Trade Center incident. And it's a rare example of a government entity being proactive in advance of the problem becoming apparent to everybody to take some steps to address the problem of how these samples would be handled after a real incident.

MODERATOR: Was this the result of a scientific panel analysis of the potential problems and sort of future war game planning?

EADON, G.: I think it was just a recognition that there are a number of scenarios that are out there in which either the CDC laboratory itself would be incapacitated by some sort of an attack, or alternatively that the demand for sample analysis would be so great that they just simply couldn't handle it, even though they are a large facility.

MODERATOR: I see. Right. Well, last month we had staff from the biomedical lab here, and they talked to us about the national network of laboratory facilities that are now available around the country in that area. What about in the chemical arena?

EADON, G.: Well, there's something very analogous to that. My next slide shows you the five states that were successful in the competition to become one of these centers for doing very sophisticated testing of clinical samples of chemical terrorist agents. They are New York, Virginia, Michigan, New Mexico, and California. And this is actually quite a rigorous program. And the goal of it is to make sure that a sample that's sent to say California or to New York would come back with the same result independent of where it was sent. And that's obviously crucial if you're going to be trying to do effective epidemiology looking at long-term health effects.

So the program starts out with the states each being provided a copy of the method as it's performed at CDC. The staff in each state study it. The staff are then brought down to Atlanta to first watch CDC perform the test and then to perform the test themselves under the supervision of CDC staff so that everybody is doing things as closely as possible.

MODERATOR: Are on the same page.

EADON, G.: As closely as possible in the same way. Then for example, the New York staff fly back to Albany where they run the procedure on essentially the identical equipment, which has been bought by the CDC grant. And at the next stage of the process is to do a validation study in which hundreds of samples of known concentration are analyzed to see how accurate and precise the results are.

And the final stage is that each of the states does proficiency test samples four times a year. And these are unknown samples that are provided to the states. And they're basically graded depending on how close to the correct answer they get. And if they're an approved status, I think that means you can be confident that the data that's generated by all of the approved status laboratories are going to be interchangeable.

MODERATOR: Right, which is critical if you’re looking at it from a national perspective in trying to determine health effects?

EADON, G.: That's correct.

MODERATOR: Alright. Well, let's talk about the role a little bit of New York Departments of Health. Wadsworth Center is in this network, which I gather is now expanding beyond the first five to a further level.

EADON, G.: Right. And the next slide gives us an opportunity to talk about what happened in 2003. The program remained pretty much stable between '99 and 2003, but in that year as Department of Homeland Security became more involved in it, the program was expanded both in the number of participants and in its scope. The other states, as well as the three largest cities and a number of territories, were given the opportunity to join the program and to select their level of participation. And the states which are indicated in orange elected to become what are called level-two laboratories in the chemical jargon. And that means that they are developing the capacity to perform clinical tests of moderate complexity.

And the states and territories that opted to be level-one are indicated in yellow. And those states are primarily serving as sample collection and sample transport sites. The idea is that they would collect and ship samples to other laboratories in the lab resource network that had greater laboratory capacity.

Now one thing I did want to mention about this is I indicated that the scope of the program had increased. And what I mean by that is that in addition to these sorts of wet laboratory responsibilities, every state had to assume a broader range of responsibilities - more or less organizational things. And I think that perhaps the most crucial of these is that each state is required to develop a plan to, in essence, process any kind of sample that might be required after a chemical terrorism attack for any kind of agent. And by any kind of sample I mean food, I mean environment - which would include water, air, or soil. I mean clinical. For example, veterinary would be another possibility that there aren't many laboratories capable of handling.

Now it doesn't require that the state laboratory be able to do these tests. It requires that it come up with a plan to get the test done if it's actually needed.

MODERATOR: Okay. We'll let's talk a little quickly here about what would actually happen in regard to analyzing samples and dealing with samples in the event of a chemical attack. I know you have a fairly detailed slide about that. And we've got a little bit of time left but not a lot.

EADON, G.: Okay. Well, CDC has enunciated a plan as to what they expect to happen after a chemical attack. I think in the context of the latest Persian Gulf War - one of our generals remarked that you need to have a well worked out plan before you go into battle, but after the first shot is fired, the plan is obsolete. And so I'm not completely convinced that this slide describes what would actually happen after an event. But this is the best we've got so far.

And basically the idea is that either the local or state jurisdiction or the FBI will notify CDC that there is a chemical event that requires the processing of human samples. And samples would be collected and shipped directly to CDC. And CDC itself will perform PCR testing and the rapid toxic screen on the first 40 samples that are collected.

Now PCR, I think this audience is mostly familiar with what that involves. That's basically a way of telling whether there are infectious agents present in the sample in case this is an infectious agent attack that was mistaken as a chemical attack or in case we're dealing with a mixed agent.

The rapid toxic screen I'll tell you about in just a minute or so. The final step is that after these samples have been analyzed and CDC knows exactly what agent we're looking for, they'll advise the members of the LRN in the other 50 states how to proceed on analyzing these samples. And what they'll do then is called targeted analysis. They'll be looking for a specific compound, sarin let's say, instead of looking for one of a much larger of possibilities.

MODERATOR: Alright. Okay. Let's talk a little bit about this rapid toxic analysis screen that you've identified here.

EADON, G.: Right. Well, the rapid toxic screen is something that at present and for the foreseeable future can really only be done at CDC, because they have a much larger instrumental and staff capacity really than any combination of state public health laboratories do. And what they're going to do is to take the first 40 samples that they receive and analyze them for a total of about 150 different agents and report the results back within 36 hours. And the reason they can do this, and for example New York can't, is because we can't do ten different procedures at once.

MODERATOR: I see.

EADON, G.: We basically have enough instrumentation to do one or two procedures at once, and we wouldn't be able to complete it in 36 hours.

MODERATOR: Right. So they have this incredible new strong capacity.

EADON, G.: That's right. They've received substantial new resources as a result of the concern over chemical terrorism.

MODERATOR: Now where can public health people in our audience learn more about the protocol for collecting samples?

EADON, G.: Well, as you can see in the next slide, these protocols are available at CDC's website, their public website. And the address is given at the bottom of the slide. In our state, we've posted slightly customized protocols on our own website, which is secure and not available to people other than the public health and medical community. My guess is that most of the other states similarly have a secure website where this information is posted.

For New York, it's basically the same sample collecting procedure with some additional information about how to contact the state authorities and where to ship them if they're going to go to Wadsworth.

MODERATOR: And then in the chain of events, the chemical specimens are collected at hospitals. Right?

EADON, G.: Right. And as the next slide I think indicates, the process of collecting clinical samples will begin at the hospitals. We expect that's where the blood and urine will be collected. We've already begun the process of training the hospital staff on how to collect and ship samples. And we haven't finished that process. It needs to continue. It's worth mentioning that it's really not terrifically different in its general makeup than what a typical hospital laboratory does every day.

MODERATOR: Okay. Now environmental samples, the collection there?

EADON, G.: Well, environmental samples -- What's going to happen with those is not as well worked out. The expectation is that the environmental samples would be collected in or near the hot zone, in or near the zone of high contamination.

MODERATOR: Right.

EADON, G.: One of the things we all need to remember is that staff that enter the hot zone are going to need to use level A equipment; what people colloquially refer to as moon suits. And that has implications as we'll see in a minute. Now we have already developed and are just about to post our conventional or common use procedures for collecting environmental samples on the Health Department's secure network, as we'll see on the next slide.

MODERATOR: Okay.

EADON, G.: And these are not really very different from the procedures that EPA recommends for collecting environmental samples. Once again, they're customized to reflect our particular preferences and our particular equipment situation. But what we need to do we now realize is to modify those procedures to make them convenient and easy for people who are wearing this bulky, level A equipment where they can't hear things very well and where their hands are in gloves so they can't turn and manipulate knobs very effectively.

And one thing I think we all need to remember is that if you as a public health laboratory plan to collect environmental samples, you need to have someone who you've worked with who is level A-certified to go out and collect those samples.

And in New York State, we are very fortunate in that the Office of Fire Prevention and Control are part of the Department of State has I guess about a hundred people who are level A certified around the state and who have agreed to assist in this matter. Otherwise, it would be a long while before you actually were able to collect environmental sample.

MODERATOR: Right. Which gives us a chance to stress again the importance of collaboration and cooperation with the different agencies we’ve been talking about in this whole public health series?

EADON, G.: That's correct.

MODERATOR: What are the key things our public health audience needs to keep in mind in collecting these samples and in the event of a chemical emergency?

EADON, G.: Okay. Well, as the next slide shows, there are a couple things that need to be emphasized. And one is that Wadsworth's chemistry lab at least, only accepts chemical samples from public health and law enforcement. We basically need someone to screen out the noise from the sample submission process and make sure that the sample is one that either poses a legitimate public health threat or has some implications for law enforcement. We really don't have the resources to do the classical white powder collected at the Dunkin Donuts that someone suspects is a chemical terrorist agent for no good reason.

Additionally, I think I need to mention that no single laboratory in the world has the range of tests needed to address any kind of chemical terrorism incident. There are just too many agents and too many different types of samples. And no single laboratory in the world has the capacity to provide all of the tests that will be requested after one of these major incidents. And certainly, we all recall at the World Trade Center incident tied up most of the environmental laboratory capacity in the northeast for weeks and months.

MODERATOR: That's right.

EADON, G.: So no single laboratory is going to do that. And that's why we have laboratory networks. The idea is that we'll share the load and spread the work around in so far as possible. And that's what we're working to create under this grant, an effective network for sharing the workload as far as possible.

MODERATOR: Okay. Well, we're almost out of time, but just before we close, if someone has a sample to submit, what should they do? I know you have a slide with an address here on it.

EADON, G.: That's correct. And as you'll see, the first thing you should do if you want to send a sample to Wadsworth is to call us. And really there are three reasons for that. First, we can't handle all kinds of samples and all kinds of analyses. And if there's a place that can handle it more effectively and better and it's an emergency, we'd like to help get it there rather than have it sent here and then have us reship it.

Additionally, if it's a real emergency, we need to make sure that we've done everything we can to get ready to do it before the sample actually arrives. And that means A) perhaps rousting staff out of bed in the middle of the night and getting them into the laboratories, and B) getting started in calibrating the instrumentation to actually perform the tests. So give us a call, and that'll be very helpful.

MODERATOR: Dr. Eadon, thank you very much. This was extraordinarily informative, but I'm afraid that's all the time we have today. We'll have to take your questions by fax or e-mail later on. Thanks for coming with us today in this assessment of chemical exposure. And thank you all in the audience for joining us. We would appreciate it if you would take a moment to fill out your evaluations, either online or send them in by hard copy. This program will be available via web streaming next week. Please check our website for more information.

We hope you'll join us on February 3rd for a program on Redefining Readiness: Terrorism Planning through the Eyes of the Public with Dr. Roz Lasker, Director of the Division of Public Health and the Center for Advancement of Collaborative Strategies at the New York Academy of Medicine. A link to her article on Redefining Readiness can be found on our website.

I'm Peter Slocum. See you next time at the University at Albany Center for Public Health Preparedness Grand Rounds series.

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