FLI Podcast (Part 2): Anthrax, Agent Orange, and Yellow Rain: Verification Stories with Matthew Meselson and Max Tegmark

In this special two-part podcast Ariel Conn is joined by Max Tegmark for a conversation with Dr. Matthew Meselson, biologist and Thomas Dudley Cabot Professor of the Natural Sciences at Harvard University. Dr. Meselson began his career with an experiment that helped prove Watson and Crick’s hypothesis on the structure and replication of DNA. He then got involved in arms control, working with the US government to renounce the development and possession of biological weapons and halt the use of Agent Orange and other herbicides in Vietnam. From the cellular level to that of international policy, Dr. Meselson has made significant contributions not only to the field of biology, but also towards the mitigation of existential threats.   

Part Two focuses on three major incidents in the history of biological weapons: the 1979 anthrax outbreak in Russia, the use of Agent Orange and other herbicides in Vietnam, and the Yellow Rain controversy in the early 80s. Dr. Meselson led the investigations into all three and solved some perplexing scientific mysteries along the way.

Topics discussed in this episode include:

  • The value of verification, regardless of the challenges
  • The 1979 Sverdlovsk anthrax outbreak
  • The use of “rainbow” herbicides during the Vietnam War, including Agent Orange
  • The Yellow Rain Controversy

Publications and resources discussed in this episode include:

  • The Sverdlovsk anthrax outbreak of 1979, Matthew Meselson, Jeanne Guillemin, Martin Hugh-Jones, Alexander Langmuir, Ilona Popova, Alexis Shelokov, and Olga Yampolskaya, Science, 18 November 1994, Vol. 266, pp 1202-1208.
  • Preliminary Report- Herbicide Assessment Commission of the American Association for the Advancement of Science, Matthew Meselson, A. H. Westing, J. D. Constable, and Robert E. Cook, 30 December 1970, private circulation, 8 pp. Reprinted in Congressional Record, U.S. Senate, Vol. 118-part 6, 3 March 1972, pp 6806-6807.
  • “Background Material Relevant to Presentations at the 1970 Annual Meeting of the AAAS”, Herbicide Assessment Commission of the AAAS, with A.H. Westing and J.D. Constable, December 1970, private circulation, 48 pp. Reprinted in the Congressional Record, U.S. Senate, Vol. 118-part 6, 3 March 1972, pp 6807-6813.
  • “The Yellow Rain Affair: Lessons from a Discredited Allegation”, with Julian Perry Robinson Terrorism, War, or Disease? eds. A.L. Clunan, P.R. Lavoy, and SB Martin, Stanford University Press, Stanford, California. 2008, pp 72-96.
  • Yellow Rain by Thomas D. Seeley, Joan W. Nowicke, Matthew Meselson, Jeanne Guillemin and Pongthep Akratanakul, Scientific American, September 1985, Vol. 253, pp 128-137.

Click here for Part 1: From DNA to Banning Biological Weapons with Matthew Meselson and Max Tegmark

Four-ship formation on a defoliation spray run. (U.S. Air Force photo)

Ariel: Hi everyone. Ariel Conn here with the Future of Life Institute. And I would like to welcome you to part two of our two-part FLI podcast with special guest Matthew Meselson and special guest/co-host Max Tegmark. You don’t need to have listened to the first episode to follow along with this one, but I do recommend listening to the other episode, as you’ll get to learn about Matthew’s experiment with Franklin Stahl that helped prove Watson and Crick’s theory of DNA and the work he did that directly led to US support for a biological weapons ban. In that episode, Matthew and Max also talk about the value of experiment and theory in science, as well as how to get some of the world’s worst weapons banned. But now, let’s get on with this episode and hear more about some of the verification work that Matthew did over the years to help determine if biological weapons were being used or developed illegally, and the work he did that led to the prohibition of Agent Orange.

Matthew, I’d like to ask about a couple of projects that you were involved in that I think are really closely connected to issues of verification, and those are the Yellow Rain Affair and the Russian Anthrax incident. Could you talk a little bit about what each of those was?

Matthew: Okay, well in 1979, there was a big epidemic of anthrax in the Soviet city of Sverdlovsk, just east of the Ural mountains, in the beginning of Siberia. We learned about this epidemic not immediately but eventually, through refugees and other sources, and the question was, “What caused it?” Anthrax can occur naturally. It’s commonly a disease of bovids, that is cows or sheep, and when they die of anthrax, the carcass is loaded with the anthrax bacteria, and when the bacteria see oxygen, they become tough spores, which can last in the earth for a long, long time. And then if another bovid comes along and manages to eat something that’s got those spores, he might get anthrax and die, and the meat from these animals who died of anthrax, if eaten, can cause gastrointestinal anthrax, and that can be lethal. So, that’s one form of anthrax. You get it by eating.

Now, another form of anthrax is inhalation anthrax. In this country, there were a few cases of men who worked in leather factories with leather that had come from anthrax-affected animals, usually imported, which had live anthrax spores on the leather that got into the air of the shops where people were working with the leather. Men would breathe this contaminated air and the infection in that case was through the lungs.

The question here was, what kind of anthrax was this: inhalational or gastrointestinal? And because I was by this time known as an expert on biological weapons, the man who was dealing with this issue at the CIA in Langley, Virginia — a wonderful man named Julian Hoptman, a microbiologist by training — asked me if I’d come down and work on this problem at the CIA. He had two daughters who were away at college, and so he had a spare bedroom, so I actually lived with Julian and his wife. And in this way, I was able to talk to Julian night and day, both at the breakfast and dinner table, but also in the office. Of course, we didn’t talk about classified things except in the office.

Now, we knew from the textbooks that the incubation period for inhalation anthrax was thought to be four, five, six, seven days; Between the time you inhale it, four, five days later, if you hadn’t yet come down with it, you probably wouldn’t. Well, we knew from classified sources that people were dying of this anthrax over a period of six weeks, April all the way into the middle of May 1979. So, if the incubation period was really that short, you couldn’t explain how that would be airborne because a cloud goes by right away. Once it’s gone, you can’t inhale it anymore. So that made the conclusion that it was airborne difficult to reach. You could still say, well maybe it got stirred up again by people cleaning up the site, maybe the incubation period is longer than we thought, but there was a problem there.

And so the conclusion of our working group was that it was probable that it was airborne. In the CIA, at that time at least, in a conclusion that goes forward to the president, you couldn’t just say, “Well maybe, sort of like, kind of like, maybe if …” Words like that just didn’t work, because the poor president couldn’t make heads nor tails. Every conclusion had to be called “possible,” “probable,” or “confirmed.” Three levels of confidence.

So, the conclusion here was that it was probable that it was inhalation, and not ingestion. The Soviets said that it was bad meat, but I wasn’t convinced, mainly because of this incubation period thing. So I decided that the best thing to do would be to go and look. Then you might find out what it really was. Maybe by examining the survivors or maybe by talking to people — just somehow, if you got over there, with some kind of good luck, you could figure out what it was. I had no very clear idea, but when I would meet any high level Soviet, I’d say, “Could I come over there and bring some colleagues and we would try to investigate?”

The first time that happened was with a very high-level Soviet who I met in Geneva, Switzerland. He was a member of what’s called the Military Industrial Commission in the Soviet Union. They decided on all technical issues involving the military, and that would have included their biological weapons establishments, and we knew that they had a big biological laboratory in the city of Sverdlovsk, there was no doubt about that. So, I told them, “I want to go in and inspect. I’ll bring some friends. We’d like to look.” And he said, “No problem. Write to me.”

So, I wrote to him, and I also went to the CIA and said, “Look, I got to have a map because maybe they’d let me go there and take me to the wrong place, and I wouldn’t know it’s the wrong place, and I wouldn’t learn anything. So, the CIA gave me a map — which turned out to be wrong, by the way — but then I got a letter back from this gentleman saying no, actually they couldn’t let us go because of the shooting down of the Korean jet #007, if any of you remember that. A Russian fighter plane shot down a Korean jet — a lot of passengers on it and they all got killed. Relations were tense. So, that didn’t happen.

Then the second time, an American and the Russian Minister of Health got a Nobel prize. The winner over there was the minister of health named Chazov, and the fellow over here was Bernie Lown in our medical school, who I knew. So, I asked Bernie to take a letter when he went next time to see his friend Chazov in Moscow, to ask him if he could please arrange that I could take a team to Sverdlovsk, to go investigate on site. And when Bernie came back from Moscow, I asked him and he said, “Yeah. Chazov says it’s okay, you can go.” So, I sent a telex — we didn’t have email — to Chazov saying, “Here’s the team. We want to go. When can we go?” So, we got back a telex saying, “Well, actually, I’ve sent my right-hand guy who’s in charge of international relations to Sverdlovsk, and he looked around, and there’s really no evidence left. You’d be wasting your time,” which means no, right? So, I telexed back and said, “Well, scientists always make friends and something good always comes from that. We’d like to go to Sverdlovsk anyway,” and I never heard back. And then, the Soviet Union collapses, and we have Yeltsin now, and it’s the Russian Republic.

It turns out that a group of — I guess at that time they were still Soviets — Soviet biologists came to visit our Fort Detrick, and they were the guests of our Academy of Sciences. So, there was a welcoming party, and I was on the welcoming party, and I was assigned to take care of one particular one, a man named Mr. Yablokov. So, we got to know each other a little bit, and at that time we went to eat crabs in a Baltimore restaurant, and I told him I was very interested in this epidemic in Sverdlovsk, and I guess he took note of that. He went back to Russia and that was that. Later, I read in a journal that the CIA produced, abstracts from the Russian literature press, that Yeltsin had ordered his minister, or his assistant for Environment and Health, to investigate the anthrax epidemic back in 1979, and the guy who he appointed to do this investigation for him was my Mr. Yablokov, who I knew.

So, I sent a telex to Mr. Yablokov saying, “I see that President Yeltsin has asked for you to look into this old epidemic and decide what really happened, and that’s great, I’m glad he did that, and I’d like to come and help you. Could I come and help you?” So, I got back a telex saying, “Well, it’s a long time ago. You can’t bring skeletons out of the closet, and anyway, you’d have to know somebody there.” Basically it was a letter that said no. But then my friend Alex Rich of Cambridge Massachusetts, a great molecular biologist and X-ray crystallographer at MIT, had a party for a visiting Russian. Who is the visiting Russian but a guy named Sverdlov, like Sverdlovsk, and he’s staying with Alex. And Alex’s wife came over to me and said, “Well, he’s a very nice guy. He’d been staying with us for several days. I make him breakfast and lunch. I make the bed. Maybe you could take him for a while.”

So we took him into our house for a while, and I told him that I had been given a turn down by Mr. Yablokov, and this guy whose name is Sverdlov, which is an immense coincidence, said, “Oh, I know Yablokov very well. He’s a pal. I’ll talk to him. I’ll get it fixed so you can go.” Now, I get a letter. In this letter, handwritten by Mr. Yablokov, he said, “Of course, you can go, but you’ve got to know somebody there to invite you.” Oh, who would I know there?

Well, there had been an American Physicist, a solid-state physicist named Ellis who was there on a United States National Academy of Sciences–Russian Academy of Sciences Exchange Agreement doing solid-state physics with a Russian solid-state physicist there in Sverdlovsk. So, I called Don Ellis and I asked him, “That guy who you cooperated with in Sverdlovsk — whose name was Gubanov — I need someone to invite me to go to Sverdlovsk, and you probably still maintain contact with him over there in Sverdlovsk, and you could ask him to invite me.” And Don said, “I don’t have to do that. He’s visiting me today. I’ll just hand him the telephone.”

So, Mr. Gubanov comes on the telephone and he says, “Of course I’ll invite you, my wife and I have always been interested in that epidemic.” So, a few days later, I get a telex from the rector of the university there in Sverdlovsk, who was a mathematical physicist. And he says, “The city is yours. Come on. We’ll give you every assistance you want.” So we went, and I formed a little team, which included a pathologist, thinking maybe we’ll get ahold of some information of autopsies that could decide whether it was inhalation or gastrointestinal. And we need someone who speaks Russian; I had a friend who was a virologist who spoke Russian. And we need a guy who knows a lot about anthrax, and veterinarians know a lot about anthrax, so I got a veterinarian. And we need an anthropologist who knows a lot about how to work with people and that happened to be my wife, Jeanne Guillemin.

So, we all go over there, we were assigned a solid-state physicist, a guy named Borisov, to take us everywhere. He knew how to fix everything. Cars that wouldn’t work, and also the KGB. He was a genius, and became a good friend. It turns out that he had a girlfriend, and she, by this time, had been elected to be a member of the Duma. In other words, she’s a congresswoman. She’s from Sverdlovsk. She had been a friend of Yeltsin. She had written Yeltsin a letter, which my friend Borisov knew about, and I have a photocopy of the letter. What it says is, “Dear Boris Nikolayevich,”that’s Yeltsin, “My constituents here at Sverdlovsk want to know if that anthrax epidemic was caused by a government activity or not. Because if it was, the families of those who died — they’re entitled to double pension money, just like soldiers killed in war.” So, Yeltsin writes back, “We will look into it.” And that’s why my friend Yablokov got asked to look into it. It was decided eventually that it was the result of government activity — by Yeltsin, he decided that — and so he had to have a list of the people who were going to get the extra pensions. Because otherwise everybody would say, “I’d like to have an extra pension.” So there had to be a list.

So she had this list with 68 names of the people who had died of anthrax during this time period in 1979. The list also had the address where they lived. So,now my wife, Jeanne Guillemin, Professor of Anthropology at Boston College, goes door-to-door — with two Russian women who were professors at the university and who knew English so they could communicate with Jeanne — knocks on the doors: “We would like to talk to you for a little while. We’re studying health, we’re studying the anthrax epidemic of 1979. We’re from the university.”

Everybody let them in except one lady who said she wasn’t dressed, so she couldn’t let anybody in. So in all the other cases, they did an interview and there were lots of questions. Did the person who died have TB? Was that person a smoker? One of the questions was where did that person work, and did they work in the day or the night? We asked that question because we wanted to make a map. If it had been inhalation anthrax, it had to be windborne, and depending on the wind, it might have been blown in a straight line if the wind was of a more or less unchanging direction.

If, on the other hand, it was gastrointestinal, people get bad meat from black market sellers all over the place, and the map of where they were wouldn’t show anything important, they’d just be all over the place. So, we were able to make a map when we got back home, we went back there a second time to get more interviews done, and Jeanne went back a third time to get even more interviews done. So, finally we had interviews with families of nearly all of those 68 people, and so we had 68 map locations: where they lived, and where they worked, and whether it was day or night. Nearly all of them were daytime workers.

When we plotted where they lived, they lived all over the southern part of the city of Sverdlovsk. When we plotted where they were likely would have been in the daytime, they all fell in to one narrow zone with one point at the military biological lab. The lab was inside the city. The other point was at the city limit: The last case was at the edge of the city limit, the southern part. We also had meteorological information, which I had brought with me from the United States. We knew the wind direction every three hours, and there was only one day when the wind was constantly blowing in the same direction, and that same direction was exactly the direction along which the people who died of anthrax lived.

Well, bad meat does not blow around in straight lines. Clouds of anthrax spores do. It was rigorous: We could conclude from this, with no doubt whatsoever, that it had been airborne, and we published this in Science magazine. It was really a classic of epidemiology, you couldn’t ask for anything better. Also, the autopsy records were inspected by the pathologist along with our trip, and he concluded from the autopsy specimens that it was inhalation. So, there was that evidence, too, and that was published in the PNAS. So, that really ended the mystery. The Soviet explanation was just wrong, and the CIA explanation, which was only probable: it was confirmed.

Max: Amazing detective story.

Matthew: I liked going out in the field, using whatever science I knew to try and deal with questions of importance to arms control, especially chemical and biological weapons arms control. And that happened to me on three occasions, one I just told you. There were two others.

Ariel: So, actually real quick before you get into that. I just want to mention that we will share or link to that paper and the map. Because I’ve seen the map that shows that straight line, and it is really amazing, thank you.

Matthew: Oh good.

Max: I think at the meta level this is also a wonderful example of what you mentioned earlier there, Matthew, about verification. It’s very hard to hide big programs because it’s so easy for some little thing to go wrong or not as planned and then something like this comes out.

Matthew: Exactly. By the way, that’s why having a verification provision in the treaty is worth it even if you never inspect. Let’s say that the guys who are deciding whether or not to do something which is against the treaty, they’re in a room and they’re deciding whether or not to do it. Okay? Now it is prohibited by a treaty that provides for verification. Now they’re trying to make this decision and one guy says, “Let’s do it. They’ll never see it. They’ll never know it.” Another guy says, “Well, there is a provision for verification. They may ask for a challenge inspection.” So, even the remote possibility that, “We might get caught,” might be enough to make that meeting decide, “Let’s not do it.” If it’s not something that’s really essential, then there is a potential big price.

If, on the other hand, there’s not even a treaty that allows the possibility of a challenge inspection, if the guy says, “Well, they might find it,” the other guy is going to say, “How are they going to find it? There’s no provision for them going there. We can just say, if they say, ‘I want to go there,’ we say, ‘We don’t have a treaty for that. Let’s make a treaty, then we can go to your place, too.’” It makes a difference: Even a provision that’s never used is worth having. I’m not saying it’s perfection, but it’s worth having. Anyway, let’s go on to one of these other things. Where do you want me to go?

Ariel: I’d really love to talk about the Agent Orange work that you did. So, I guess if you could start with the Agent Orange research and the other rainbow herbicides research that you were involved in. And then I think it would be nice to follow that up with, sort of another type of verification example, of the Yellow Rain Affair.

Matthew: Okay. The American Association for the Advancement of Science, the biggest organization of science in the United States, became, as the Vietnam War was going on, more and more concerned that the spraying of herbicides in Vietnam might cause ecological or health harm. And so at successive national meetings, there were resolutions to have it looked into. And as a result of one of those resolutions, the AAAS asked a fellow named Fred Tschirley to look into it. Fred was at the Department of Agriculture, but he was one of the people who developed the military use of herbicides. He did a study, and he concluded that there was no great harm. Possibly to the mangrove forest, but even then they would regenerate.

But at the next annual meeting, there was more appealing on the part of the membership, and now they wanted the AAAS to do its own investigation, and the compromise was they’d do their own study to design an investigation, and they had to have someone to lead that. So, they asked a fellow named John Cantlon, who was provost of Michigan State University, would he do it, and he said yes. And after a couple of weeks, John Cantlon said, “I can’t do this. I’m being pestered by the left and the right and the opponents on all sides and it’s just, I can’t do it. It’s too political.”

So, then they asked me if I would do it. Well, I decided I’d do it. The reason was that I wanted to see the war. Here I’d been very interested in chemical and biological weapons; very interested in war, because that’s the place where chemical and biological weapons come into play. If you don’t know anything about war, you don’t know what you’re talking about. I taught a course at Harvard for over two years on war, but that wasn’t like being there. So, I said I’d do it.

I formed a little group to do it. A guy named Arthur Westing, who had actually worked with herbicides and who was a forester himself and had been in the army in Korea, and I think had a battlefield promotion to captain. Just the right combination of talents. Then we had a chemistry graduate student, a wonderful guy named Bob Baughman. So, to design a study, I decided I couldn’t do it sitting here in Cambridge, Massachusetts. I’d have to go to Vietnam and do a pilot study in order to design a real study. So, we went to Vietnam — by the way, via Paris, because I wanted to meet the Vietcong people, I wanted them to give me a little card we could carry in our boots that would say, if we were captured, “We’re innocent scientists, don’t imprison us.” And we did get such little cards that said that. We were never captured by the Vietcong, but we did have some little cards.

Anyway, we went to Vietnam and we found, to my surprise, that the military assistance command, that is the United States Military in Vietnam, very much wanted to help our investigation. They gave us our own helicopter. That is, they assigned a helicopter and a pilot to me. And anywhere we wanted to go, I’d just call a certain number the night before and then go to Tan Son Nhut Air Base, and there would be a helicopter waiting with a pilot instructed FAD — fly as directed.

So, one of the things we did was to fly over a valley on which herbicides had been sprayed to kill the rice. John Constable, the medical member of our team, and I did two flights of that so we could take a lot of pictures. And the man who had designed this mission, a chemical corps captain named Captain Franz, had designed the mission and requested it and gotten permission through a series of review processes that it was really an enemy crop production area, not an area of indigenous Montagnard people growing food for their own eating, but rather enemy soldiers growing it for themselves.

So we took a lot of pictures and as we flew, Colonel Franz said, “See down there, there are no houses. There’s no civilian population. It’s just military down there. Also, the rice is being grown on terraces on the hillsides. The Montagnard people don’t do that. They just grow it down in the valley. They don’t practice terracing. And also, the extent of the rice fields down there — that’s all brand new. Fields a few years ago were much, much smaller in area. So, that’s how we know that it’s an enemy crop production area.” And he was a very nice man, and we believed him. And then we got home, and we had our films developed.

Well, we had very good cameras and although you couldn’t see from the aircraft, you could certainly see in the film: The valley was loaded with little grass shacks with yellow roofs — meaning that they were built recently, because you have to replace the roofs every once in a while with straw and if it gets too old, it turns black, but if there’s yellow, it means that somebody is living in those. And there were hundreds and hundreds of them.

We got from the Food and Agriculture Organization in Rome how much rice you need to stay alive for one year, and what area in hectares of dry rice — because this isn’t patty rice, it’s dry rice — you’d need to make that much rice, and we measured the area that was under cultivation from our photographs, and the area was just enough to support that entire population, if we assumed that there were five people who needed to be fed in every one of the houses that we counted.

Also, we could get from the French aerial photography that they had done in the late 1940s, and it turns out that the rice fields had not expanded. They were exactly the same. So it wasn’t that the military had moved in and made bigger rice fields: They were the same. So, everything that Colonel Franz said was just wrong. I’m sure he believed it, but it was wrong.

So, we made great big color enlargements of our photographs — we took photographs all up and down this valley, 15 kilometers long — and we made one set for Ambassador Bunker; one copy for General Abrams — Creighton Abrams was the head of our military assistance command; and one set for Secretary of State Rogers; along with a letter saying that this one case that we saw may not be typical, but in this one case, this crop destruction program was achieving the opposite of what it intended. It was denying food to the civilian population and not to the enemy. It was completely mistaken. So, as a result, I think, of that, but I have no proof, only the time connection, but right after that in early November — we’d sent the stuff in early November — Ambassador Bunker and General Abrams ordered a new review of the crop destruction program. Was it in response to our photographs and our letter? I don’t know, but I think it was.

The result of that review was a recommendation by Ambassador Bunker and General Abrams to stop the herbicide program immediately. They sent this recommendation back in a top secret telegram to Washington. Well, the top-secret telegram fell into the hands of the Washington Post, and they published it. Well, now here are the Ambassador and the General on the spot, saying to stop doing something in Vietnam. How on earth can anybody back in Washington gainsay them? Of course, President Nixon had to stop it right away. There’d be no grounds. How could he say, “Well, my guys here in Washington, in spite of what the people on the spot say, tell us we should continue this program.”

So that very day, he announced that the United States would stop all herbicide operations in Vietnam in a rapid and orderly manner. That very day happened to be the day that I, John Constable, and Art Westing were on the stage at the annual meeting in Chicago of the AAAS, reporting on our trip to Vietnam. And the president of AAAS ran up to me to tell me this news, because it just came in while I was talking, giving our report. So, that’s how it got stopped, and thanks to General Abrams.

By the way, the last day I was in Vietnam, General Abrams had just come back from Japan — he’d had an operation for gallbladder, and he was still convalescing. We spent all morning talking with each other. And he asked me at one point, “What about the military utility of the herbicides?” And of course, I said I had no idea what it was, or not. And he said, “Do you want to know what I think?” I said, “Yes, sir.” He said, “I think it’s shit.” I said, “Well, why are we doing it here?” He said, “You don’t understand anything about this war, young man. I do what I’m ordered to do from Washington. It’s Washington who tells me to use this stuff, and I have to use it because if I didn’t have those 55-gallon drums of herbicides offloaded on the decks at Da Nang and Saigon, then they’d make walls. I couldn’t offload the stuff I need over those walls. So, I do let the chemical corps use this stuff.” He said, “Also, my son, who is a captain up in I Corps, agrees with me about that.”

I wrote something about this recently, which I sent to you, Ariel. I want to be sure my memory was right about the conversation with General Abrams — who, by the way, was a magnificent man. He is the man who broke through at the Battle of the Bulge in World War II. He’s the man about whom General Patton, the great tank general, said, “There’s only one tank officer greater than me, and it’s Abrams.”

Max: Is he the one after whom the Abrams tank is named?

Matthew: Yes, it was named after him. Yes. He had four sons, they all became generals, and I think three of them became four-stars. One of them who did become a four-star is still alive in Washington. He has a consulting company. I called him up and I said, “Am I right, is this what your dad thought and what you thought back then?” He said, “Hell, yes. It’s worse than that.” Anyway, that’s what stopped the herbicides. They may have stopped anyway. It was dwindling down, no question. Now the question of whether dioxin and herbicides have caused too many health effects, I just don’t know. There’s an immense literature about this and it’s nothing I can say we ever studied. If I read all the literature, maybe I’d have an opinion.

I do know that dioxin is very poisonous, and there’s a prelude to this order from President Nixon to stop the use of all herbicides. That’s what caused the United States to stop the use of Agent Orange specifically. That happened first, before I went to Vietnam. That happened for a funny reason. A Harvard student, a Vietnamese boy, came to my office one day with a stack of newspapers from Saigon in Vietnamese. I couldn’t read them, of course, but they all had pictures of deformed babies, and this student claimed that this was because of Agent Orange, that the newspaper said it was because of Agent Orange.

Well, deformed babies are born all the time and I appreciated this coming from him, but there’s nothing I could do about it. But then I got from a graduate student here — Bill Haseltine, now become a very wealthy man — he had a girlfriend and she was working for Ralph Nader one summer, and she somehow got a purloined copy of a study that had been ordered by the NIH of the possible keratogenic, mutagenic, and carcinogenic effects of common herbicides, pesticides, and fungicides.

This company, called the Bionetics company, had this huge contract that tests all these different compounds, and they concluded from this that there was only one of these chemicals that did anything that might be dangerous for people. That was 2,4,5-T, trichlorophenoxyacetic acid. Well, that’s what Agent Orange is made out of. So, I had this report that had not yet been released to the public saying that this could cause birth defects in humans if it did the same thing as it did in guinea pigs and mice. I thought, the White House better know about this. That’s pretty explosive: claims in the newspapers in Saigon and scientific suggestions that this stuff might cause birth defects.

So, I decided to go down to Washington and see President Nixon’s science advisor. That was Lee DuBridge, physicist. Lee DuBridge had been the president of Caltech when I was a graduate student there and so he knew me, and I knew him. So, I went down to Washington with some friends, and I think one of the friends was Arthur Galston from Yale. He was a scientist who worked on herbicides, not on the phenoxyacetic herbicides but other herbicides. So we went down to see the President’s science advisor, and I showed them these newspapers and showed him the Bionetics report. He hadn’t seen it, it was at too low a level of government for him to see it and it had not yet been released to the public. Then he did something amazing, Lee DuBridge: He picked up the phone and he called David Packard, who was the number two at the Defense Department. Right then and there, without consulting anybody else, without asking the permission of the President, they canceled Agent Orange.

Max: Wow.

Matthew: That was the end Agent Orange. Now, not exactly the end. I got a phone call from Lee DuBridge a couple of days later when I was back at Harvard. He says, “Matt, the DuPont people have come to me. It’s not Agent Orange itself, it’s an impurity in Agent Orange called dioxin, and they know that dioxin is very toxic, and the Agent Orange that they make has very little dioxin in it because they know it’s bad and they make the stuff at low temperature, when dioxin is a by-product, that’s made in very small amount. These other companies like Diamond Shamrock and other companies, Monsanto, who make Agent Orange for the military, it must be their Agent Orange. It’s not our Agent Orange.

So, in other words the question was, we just use the Dow Agent Orange — maybe that’s safe. But the question is does the Dow Agent Orange cause defects in mice? So, a whole new series of experiments were done with Agent Orange containing much less dioxin in it. It still made birth defects. So, since it still made birth defects in one species of rodent, you could hardly say, “Well, it’s okay then for humans.” So, that really locked it, closed it down, and then even the Department of Agriculture prohibited the use in the United States, except on land that would have been unlikely to get into the human food chain. So, that ended the use of Agent Orange.

That had happened already before we went to Vietnam. They were then using only Agent White and Agent Blue, two other herbicides, but Agent Orange had been knocked out ahead of time. But that was the end of the whole herbicide program. It was two things: the dioxin concern, on the one hand, stopping Agent Orange, and the decision of President Nixon; and militarily Bunker and Abrams had said, “It’s no use, we want to get it stopped, it’s doing more harm than good. It’s getting the civilian population against us.”

Max: One reaction I have to these fascinating stories is how amazing it is that back in those days politicians really trusted scientists. You could go down to Washington, there would be a science advisor. You know, we even didn’t have a presidential science advisor for a while now during this administration. Do you feel that the climate has changed somehow in the way politicians view scientists?

Matthew: Well, I don’t have a big broad view of the whole thing. I just get the impression, like you do, that there are more politicians who don’t pay attention to science than there used to be. There are still some, but not as many, and not in the White House.

Max: I would say we shouldn’t particularly just point fingers at any particular administration, I think there has been a general downward trend for people’s respect for scientists overall. If you go back to when you were born, Matthew, and when I was born, I think generally people thought a lot more highly about scientists contributing very valuable things to society and they were very interested in them. I think right now there are much more people who can name — If you ask the average person how many famous movie stars can they name, or how many billionaires can they name, versus how many Nobel laureates can they name, the answer is going to be kind of different from the way it was a long time ago. It’s very interesting to think about what we can do to more help people appreciate the things that they do care about, like living longer and having technology and so on, are things that they, to a large extent, owe to science. It isn’t just the nerdy stuff that isn’t relevant to them.

Matthew: Well, I think movie stars were always at the top of the list. Way ahead of Nobel Prize winners and even of billionaires, but you’re certainly right.

Max: The second thing that really strikes me, which you did so wonderfully there, is that you never antagonized the politicians and the military, but rather went to them in a very constructive spirit and said look, here are the options. And based on the evidence, they came to your conclusion.

Matthew: That’s right. Except for the people who actually were doing these programs — that was different, you couldn’t very well tell them that. But for everybody else, yes, it was a help. You need to offer help, not hindrance.

The last thing was the Yellow Rain. That, too, involved the CIA. I was contacted by the CIA. They had become aware of reports from Southeast Asia, particularly from Thailand, Hmong tribespeople who were living in Laos, coming out of Laos across the Mekong into Thailand, and telling stories of being poisoned by stuff dropped from airplanes. Stuff that they called kemi or yellow rain.

At first, I thought maybe there was something to this, there are some nasty chemicals that are yellow. Not that lethal, but who knows, maybe there is exaggeration in their stories. One of them is called adamsite, it’s yellow, it’s an arsenical. So we decided we’d have a conference, because there was a  mystery: What is this yellow rain? We had a conference. We invited people from the intelligence community, from the state department. We invited anthropologists. We invited a bunch of people to ask, what is this yellow rain?

By this time, we knew that the samples that had been turned in contained pollen. One reason we knew that was that the British had samples of this yellow rain and they had shown that it contains pollen. They had looked at the samples of the yellow rain brought in by the Hmong tribespeople, given to British officers — or maybe Americans, I don’t know — but found its way into the hands of British intelligence, who bring these samples back to Porton and they’re examined in various ways, but also under the microscope. And the fellow who looked at them under the microscope happened to be a beekeeper. He knew just what pollen grains look like. And he knew that there was pollen, and then they sent this information to the United States, and we looked at the samples of yellow rain we had, and they all contained — all these yellow samples contained pollen.

The question was, what is it? It’s got pollen in it. Maybe it’s very poisonous. The Montagnard people say it falls from the sky. It lands on leaves and on rocks. The spots were about two millimeters in diameter. It’s yellow or brown or red, different colors. What is it? So, we had this meeting in Cambridge, and one of the people there, Peter Ashton, is a great botanist, his specialty is the trees of Southeast Asia and in particular the great dipterocarp trees, which are like the oaks in our part of the world. And he was interested in the fertilization of these dipterocarps, and the fertilization is done by bees. They collect pollen, though, like other bees.

And so the hypothesis we came to at the end of this day-long meeting was that maybe this stuff is poisonous, and the bees get poisoned by it because it falls on everything, including flowers that have pollen, and the bees get sick, and these yellow spots, they’re the vomit of the bees. These bees are smaller individually than the yellow spots, but maybe several bees get together and vomit on the same spot. Really a crazy idea. Nevertheless, it was the best idea we could come up with that explained why something could be toxic but have pollen in it. It could be little drops, associated with bees, and so on.

A couple of days later, both Peter Ashton, the botanist, and I, noticed on the backs of our cars on the windshields, the rear windshields, yellow spots loaded with pollen. These were being dropped by bees,  these were the natural droppings of bees, and that gave us the idea that maybe there was nothing poisonous in this stuff. Maybe it was the natural droppings of bees that the people in the villages thought was poisonous, but that wasn’t. So, we decided we better go to Thailand and find out what’s happening.

So, a great bee biologist named Thomas Seeley, who’s now at Cornell — he was at Yale at that time — and I flew over to Thailand, and went up into the forest to see if bees defecate in showers. Now why did we do that? It’s because friends here said, “Matt, this can’t be the source of the yellow rain that the Hmong people complained about, because bees defecate one by one. They don’t go out in a great armada of bees and defecate all at once. Each bee goes out and defecates by itself. So, you can’t explain the showers — they’d only get tiny little driblets, and the Hmong people say they’re real showers, with lots of drops falling all at once.”

So, Tom Seeley and I went to Thailand, where they also had this kind of bee. So, we went there, and it turns out that they defecate all at once, unlike the bees here. Now they do defecate in showers here too, but they’re small showers. That’s because the number of bees in a nest here is rather small, but they do come out on the first warm days of spring, when there’s now pollen and nectar to be harvested, but those showers are kind of small. Besides that, the reason that there are showers at all even in New England is because the bees are synchronized by winter. Winter forces them to stay in their nest all winter long, during which they’re eating the stored-up pollen and getting very constipated. Now, when they fly out, they all fly out, they’re all constipated, and so you get a big shower. Not as big as the natives in Southeast Asia reported, but still a shower.

But in southeast Asia, there are no seasons. Too near the equator. So, there’s nothing that would synchronize the defecation of bees, and that’s why we had to go to Thailand to see if — even though there’s no winter to synchronize their defecation flights — if they nevertheless do go out in huge numbers and all at once.

So, we’re in Thailand and we go up into the Khao Yai National Park and find places where there are clearings in the forests where you could see up into the sky, where if there were bees defecating their feces would fall to the ground, not get caught up in the trees. And we put down big pieces, one meter square, of white paper, and anchored them with rocks, and went walking around in the forest some more, and come back and look at our pieces of white paper every once in a while.

And then suddenly we saw a large number of spots on the paper, which meant that they had defecated all at once. They weren’t going around defecating one by one by one. There were great showers then. That’s still a question: Why they don’t go out one by one? And there are some good ideas why, I won’t drag you into that. It’s the convoy principle, to avoid getting picked off one by one by birds. That’s why people think that they go out in great armadas of constipated bees.

So, this gave us a new hypothesis. The so-called yellow rain is all a mistake. It’s just bees defecating, which people confuse and think is poisonous. Now, that still doesn’t prove that there wasn’t a poison. What was the evidence for poison? The evidence was that the Defense Intelligence Agency was sending samples of this yellow rain and also samples of human blood and other materials to a laboratory in Minnesota that knew how to analyze for the particular toxin that the Defense establishment thought was the poison. It’s a toxin called trichothecene mycotoxins, there’s a whole family of them. And this lab reported positive findings in the samples from Thailand but not in controls. So that seemed to be real proof that there was poison.

Well, this lab is a lab that also produced trichothecene mycotoxins, and the way they analyzed for them was by mass spectroscopy, and everybody knows that if you’re going to do mass spectroscopy, you’re going to be able to detect very, very, very tiny amounts of stuff, and so you shouldn’t both make large quantities and try to detect small quantities in the same room, because there’s the possibility of cross contamination. I have an internal report from the Defense Intelligence Agency saying that that laboratory did have numerous false positive, and that probably all of their results were bedeviled by contamination from the trichothecenes that were in the lab, and also because there may have been some false reading of the mass spec diagram.

The long and short of it is that when other laboratories tried to find trichothecenes in their samples: the US Army looked at at least 80 samples and found nothing. The British looked at at least 60 samples, found nothing. The Swedes looked at some number of samples, I don’t know the number, but found nothing. The French looked at a very few samples at their military analytical lab, and the French found nothing. No lab could confirm it. There was one lab at Rutgers that thought it could confirm it, but I believe that they were suffering from contamination also, because they were a lab that worked with trichothecenes also.

So, the long and short of it is that the chemical evidence was no good, and finally the ambassador there decided that we should have another look — Ambassador Dean. And that the military should send out a team that was properly equipped to check up on these stories, because up until then there was no dedicated team. There were teams that would come up briefly, listen to the refugees’ stories, collect samples, and go back. So Ambassador Dean requested a team that would stay there. So out comes a team from Washington, stays there longer than a year. Not just a week, but longer than a year, and they tried to re-locate the Hmong people in the camps who had told these stories in the refugee camps.

They couldn’t find a single one who would tell the same story twice. Either because they weren’t telling the same story twice, or because the interpreter interpreted the same story differently. So, whatever it was. Then they did something else. They tried to find people who were in the same location at the same time as was claimed there was such attacks, and those people never confirmed the attack. They could never find any confirmation by interrogation of people.

Then also, there was a CIA unit out there in that theater questioning captured prisoners of war and also people who surrendered from the North Vietnamese army: the people who were presumably behind the use of this toxic stuff. And they interrogated hundreds of people, and one of these interrogators wrote an article in an Intelligence Agency Journal, but an open journal, saying that he doubted that there was anything to the yellow rain because they had interrogated so many people including chemical corps people from the North Vietnamese Army, that he couldn’t believe that there really was anything going on.

So we did some more investigating of various kinds, not just going to Thailand, but doing some analysis of various things. We looked at the samples — we found bee hairs in the samples. We found that the bee pollen in the samples of the alleged poison had no protein inside. You can stain pollen grains with something called Coomassie brilliant blue, and these pollen grains that were in the samples handed in by the refugees, that were given to us by the army and by the Canadians, by the Australians, they didn’t stain blue. Why not? Because if a pollen grain passes through the gut of a bee, the bee digests out all of the good protein that’s inside the pollen grain, as its nutrition.

So, you’d have to believe that the Soviets were collecting pollen not from plants, which is hard enough, but had been regurgitated by bees. Well, that’s insane. You could never get enough to be a weapon by collecting bee vomit. So the whole story collapsed, and we’ve written a longer account of this. The United States government has never said we were right, but a few years ago said that maybe they were wrong. So that’s at least something.

So one case we were right, and the Soviets were wrong. Another case, the Soviets were wrong, and we were right, and the third case, the herbicides, nobody was right or wrong. It was just that it was, in my view, by the way, it was useless militarily. I’ll tell you why.

If you spray the deep forest, hoping to find a military installation that you can now see because there are no more leaves, it takes four or five weeks for the leaves to fall off. So, you might as well drop little courtesy cards that say, “Dear enemy. We have now sprayed where you are with herbicide. In four or five weeks we will see you. You may choose to stay there, in which case, we will shoot you. Or, you have four or five weeks to move somewhere else, in which case, we won’t be able to find you. You decide.” Well, come on, what kind of a brain came up with that?

The other use was along roadsides, for convoys to be safer from snipers who might be hidden in the woods. You knock the leaves off the trees and you can see deeper into the woods. That’s right, but you have to realize the fundamental law of physics, which is that if you can see from A to B, B can see back to A, right? If there’s a clear light path from one point to another, there’s a clear light path in the other direction.

Now think about it. You are a sniper in the woods, and the leaves now have not been sprayed. They grow right up to the edge of the forest and a convoy is coming down the road. You can stick your head out a little bit but not for very long. They have long-range weapons; When they’re right opposite you, they have huge firepower. If you’re anywhere nearby, you could get killed.

Now, if we get rid of all the leaves, now I can stand way back into the forest, and still sight you between the trunks. Now, that’s a different matter. A very slight move on my part determines how far up the road and down the road I can see. By just a slight movement of my eye and my gun, I can start putting you under fire a couple kilometers up the road — you won’t even know where it’s coming from. And I can keep you under fire a few kilometers down the road, when you pass me by. And you don’t know where I am anymore. I’m not right up by the roadside, because the leaves would otherwise keep me from seeing anything. I’m back in there somewhere. You can pour all kinds of fire, but you might not hit me.

So, for all these reasons, the leaves are not the enemy. The leaves are the enemy of the enemy. Not of us. We’d like to get rid of the trunks — that’s different, we do that with bulldozers. But getting rid of the leaves leaves a kind of a terrain which is advantageous to the enemy, not to us. So, on all these grounds, my hunch is that by embittering the civilian population — and after all our whole strategy was to win the hearts and minds — by embittering the native population by wiping out their crops with drifting herbicide, the herbicides helped us lose the war, not win it. We didn’t win it. But it helped us lose it.

But anyway, the herbicides got stopped in two steps. First Agent Orange, because of dioxin and the report from the Bionetics Company, and second because Abrams and Bunker said, “Stop it.” We now have a treaty, by the way, the ENMOD treaty, that makes it illegal under international law to do any kind of large-scale environmental modification as a weapon of war. So, that’s about everything I know.

And I should add: you might say, how could they interpret something that’s common in that region as a poison? Well, in China, in 1970, I believe it was, the same sort of thing happened, but the situation was very different. People believed that yellow spots were falling from the sky, they were fallout from nuclear weapons tests being conducted by the Soviet Union, and they were poisonous.

Well, the Chinese government asked a geologist from a nearby university to go investigate, and he figured out — completely out of touch with us, he had never heard of us, we had never heard of him — that it was bee feces that were being misinterpreted by the villagers as fallout from nuclear weapons test done by Russians.

It was exactly the same situation, except that in this case there was no reason whatsoever to believe that there was anything toxic there. And why was it that people didn’t recognize bee droppings for what they were? After all, there’s lots of bees out there. There are lots of bees here, too. And if in April, or near that part of spring, you look at the rear windshield of your car, if you’ve been out in the countryside or even here in midtown, you will see lots of these spots, and that’s what those spots are.

When I was trying to find out what kinds of pollen were in the samples of the yellow rain — the so-called yellow rain — that we had, I went down to Washington. The greatest United States expert on pollen grains and where they come from was at the Smithsonian Institution, a woman named Joan Nowicki. I told her that bees make spots like this all the time and she said, “Nonsense. I never see it.” I said, “Where do you park your car?” Well there’s a big parking lot by the Smithsonian, we go down there, and her rear windshield was covered with these things. We see them all the time. They’re part of what we see, but we don’t take any account of.

Here at Harvard there’s a funny story about that. One of our best scientists here, Ed Wilson, studies ants — but also bees — but mostly ants. But he knows a lot about bees. Well, he has an office in the museum building, and lots of people come to visit the museum at Harvard, a great museum, and there’s a parking lot for them. Now there’s a graduate student who has, in those days, bee nests up on top of the museum building. He’s doing some experiments with bees. But these bees defecate, of course. And some of the nice people who come to see Harvard Museum park their cars there and some of them are very nice new cars, and they come back out from seeing the museum and there’s this stuff on their windshields. So, they go to find out who is it that they can blame for this and maybe do something about it or pay them get it fixed or I don’t know what — anyway, to make a complaint. So, they come to Ed Wilson’s office.

Well, this graduate student is a graduate student of Ed Wilson, and of course, he knows that he’s got bee nests up there, and so the secretary of Ed Wilson knows what this stuff is. And the graduate student has the job of taking a rag with alcohol on it and going down and gently wiping the bee feces off of the windshields of these distressed drivers, so there’s never any harm done. But now, when I had some of this stuff that I’d collected in Thailand, I took two people to lunch at the faculty club here at Harvard, and some leaves with these spots on them under a plastic petri dish, just to see if they would know.

Now, one of these guys, Carroll Williams, knew all about insects, lots of things about insects, and Wilson of course; and we’re having lunch and I bring out this petri dish with the leaves covered with yellow spots and asked them, two professors who are great experts on insects, what the stuff is, and they hadn’t the vaguest idea. They didn’t know. So, there can be things around us that we see every day, and even if we’re experts we don’t know what it is. We don’t notice it. It’s just part of the environment. We don’t notice it. I’m sure that these Hmong people were getting shot at, they were getting napalmed, they were getting everything else, but they were not getting poisoned. At least not by bee feces. It was all a big mistake.

Max: Thank you so much, both for this fascinating conversation and all the amazing things you’d done to keep science a force for good in the world.

Ariel: Yes. This has been a really, really great and informative discussion, and I have loved learning about the work that you’ve done, Matthew. So, Matthew and Max, thank you so much for joining the podcast.

Max: Well, thank you.

Matthew: I enjoyed it. I’m sure I enjoyed it more than you did.

Ariel: No, this was great. It’s truly been an honor getting to talk with you.

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