Some of the most important and ecologically damaging chemicals used in agriculture historically — and still today, in some cases — have their origins in warfare. To share the fascinating history of how these chemicals became prevalent and how the environmental movement fought back, my guest this week is Frank von Hippel, a professor of environmental health sciences and author of “The Chemical Age: How Chemists Fought Famine and Disease, Killed Millions, and Changed Our Relationship with the Earth.”
Frank’s specialty is pollution research. He works in the University of Arizona’s Mel & Enid Zuckerman College of Public Health and leads the university’s One Health Research Initiative. He started his current position just last year after previously working at Columbia University in New York City, the University of Alaska Anchorage and Northern Arizona University. He has taught ecology field courses in more than 20 countries and conducted research in the Americas, Africa and Australia. He’s also the creator and host of the Science History Podcast.
Frank von Hippel is a professor of environmental health sciences and the author of “The Chemical Age: How Chemists Fought Famine and Disease, Killed Millions, and Changed Our Relationship with the Earth.” (photo: Courtesy of Frank von Hippel)
As the director of the One Health Research Initiative, he endeavors to bring disparate fields together to solve problems. “One Health is where you’re looking simultaneously at human health, animal health and environmental health,” he says. “This is what I do with pollution research: I study pollution problems all around the world, and in each case, we’re looking at impacts on wildlife, impacts on the environment, impacts on human health.”
When Frank set out to write “The Chemical Age” about the impacts of pesticides on health and the environment — while simultaneously working his day job as a professor — he thought it would be an 18-month writing project, he says. Instead, it took him nine years.
I must say I really enjoyed Frank’s book, as well as listening to his podcast. Frank sheds a light on how modern science came to be, and he does it in a fascinating and engaging way.
Before proceeding with my conversation with Frank about “The Chemical Age,” I want to take a second to remind you that I have a new book of my own that was released last month. It’s titled “The Vegetable Gardening Book: Your complete guide to growing an edible organic garden from seed to harvest” and can be found both online and at local bookstores. It’s chock full of insider tips and new-to-you information that will help you step up your gardening game and tackle challenges.
And on tap for 2023 is my new Online Gardening Academy™ premium course, Organic Vegetable Gardening. Sign up for the waitlist here.
The Irish Potato Famine
Frank’s book opens with the Irish Potato Famine, explaining what caused it and the measures taken to prevent it from ever happening again.
“One way to think about the Irish Potato Famine is it was the first case of a widespread disaster caused by globalization,” Frank notes.
It started with the subjugation of the Irish people by the English. Irish farmers were not allowed to do subsistence farming on productive lands because those lands were used for export crops that went to England. Instead, the farmers had to use marginal lands to grow food for their families.
“The only crop that could be grown and sustain a family on such lands was the potato,” he says.
The potato wasn’t a native crop in Ireland — it came from the Americas. But while Incan potato growers, prior to colonization, probably had a couple of hundred varieties of potatoes on their farm, Irish potato growers raised just a few varieties across the entire island.
“It was a monoculture that was highly vulnerable then to invasion by a pathogen, and in this case, the pathogen was a water mold called Phytophthora infestans — and that also came from the Americas,” Frank says.
“Phytophthora infestans” literally means “infectious plant destroyer,” and it’s as nefarious as it sounds.
There had been an effort to plant various potato varieties in Ireland that would be resistant to certain insect pests and infections, but this was a pathogen that was new to Europe. The novel pathogen wiped out potato crops all across the continent, though it was only in Ireland, where potatoes were the staple crop, that the blight caused famine.
A potato infected with late blight, showing typical rot symptoms. (Photo credit: Scott Bauer, USDA Agricultural Research Service, Bugwood.org)
“Potatoes are a fascinating crop because you can essentially live on the potato,” Frank says. “… You can have big healthy families from that crop. So they were growing varieties of potatoes that did well in that environment and Ireland but that did not have resistance to this water mold.”
The famine was a product of globalization because the pathogen could only survive by being transported quickly across the oceans in seed stock of potatoes, Frank says. “Once it hit Ireland, it caused widespread famine because the Irish people were primarily peasants living off this monoculture. And so socially it was a disaster that was waiting to happen, and it just took the spark of this invasive water mold to do it. Unfortunately, the science was not far enough along then to solve the problem.”
Back then, scientists still believed in the notion of “spontaneous generation.” They thought that microscopic organisms just arose out of nowhere and there was nothing that could be done about them.
The Irish Potato Famine lasted from 1845 to 1849, and it wasn’t until 1859 that Louis Pasteur disproved spontaneous generation.
“Over a million Irish died during the famine and over a million Irish emigrated,” Frank says. “It completely changed the nature of countries like ours in the United States, Canada, Australia, other countries with large Irish immigrant populations.”
Frank points out that when people are starving to death, they don’t actually die from a lack of food. “They die because their immune system collapses and they end up getting infectious diseases that kill them,” he says. “And in the case of the Irish Potato Famine, it was primarily typhus and relapsing fever.”
When Pasteur disproved spontaneous generation it led to the beginnings of what was the most remarkable period of public health science ever, according to Frank.
Physician and microbiologist Robert Koch, from Germany, and Pasteur, from France, discovered the pathogens that caused various pandemics and then came up with cures for them.
Unfortunately, a way to treat potato crops for the plant pathogen Phytophthora infestans wouldn’t be discovered until a couple of decades after the famine. It happened when a French botanist named Pierre-Marie-Alexis Millardet was studying a relative of the aphid named phylloxera, which in Greek means “the drying up of leaves.”
“It was an insect that was destroying the vineyards of France and spreading across Europe, and then following the infestation of phylloxera across the vineyards of France, there followed a pathogen that was wiping out the vineyards,” Frank says. “So Millardet started trying to find a solution to this, and he happened upon one by accident.”
Millardet noticed that grape vines that were growing next to paths with foot traffic were healthy, and the plants looked good — they weren’t being destroyed by the water mold that was destroying the other plants.
When Millardet questioned the viticulturists, he learned that they were spraying copper sulfate — which has a bitter taste — onto the plants next to the paths to keep pedestrians from pilfering their grapes.
“It just so happened the copper sulfate prevents the water mold spore from going through the stoma of the leaves and infecting the plant,” Frank says.
That water mold is related to Phytopthora infestas, so copper sulfate was likewise discovered as a treatment for potato blight.
“Copper sulfate then was produced in large quantities to fight water molds on potatoes, on grapes and so on and became a large commercially successful pesticide,” Frank says.
He adds that Millardet was equipped to uncover the pathogen issue while investigating phylloxera because he had medical training, which back then included a lot of botany.
“Even today, over half of Western medicines derive from plant secondary compounds,” he says. “So back then especially, that was what you had available to you, were these naturally occurring secondary compounds from plants.”
When I was recently in London, our group visited the Chelsea Physic Garden, a botanic garden founded in 1673 and planted with all the plants that were used for making medicine in England back then.
Frank has spent time with shamans in tropical rainforests in Latin America and spent five months in a rainforest in Africa learning about plants there. “It’s amazing how much local knowledge there is about medicinal treatments from plants,” he says. “This is, unfortunately, one of the things we’ve been losing with the loss of these cultures.”
Scene at Skibbereen during the Great Famine by Cork artist James Mahony, The Illustrated London News, 1847
Understanding Pesticides
The word “pesticide” is often used synonymously with “insecticide,” but “pesticide” is a much broader term. “Pesticide” literally means “kill pest,” and “pest” is anything we don’t like, Frank explains. Herbicides are designed to kill plants, insecticides to kill insects, rodenticides to kill rodents, piscicides to kill fish, and so on.
“We have many different kinds of chemicals used to kill different kinds of quote, unquote ‘pests,’ and lumped together, you can call them pesticides,” he says. “So pesticides is a more general term for chemicals designed to kill any type of pest, whether insect or otherwise.”
DDT powder, an example of an insecticide. Insecticides are pesticides, but pesticides are not all insecticides.
How Agricultural Pesticides Became War Chemicals, and Vice Versa
“These chemicals that were discovered and designed to kill insects and other kinds of pests, it turns out were also very effective — maybe in slightly different forms — at killing people, and vice versa,” Frank says.
This came to a head during World War I. He notes that by the end of the war, a quarter of artillery shells had chemical weapons in them.
“More than anything else, it was a war of chemistry, and chemists came to the forefront of the war,” he says. “It led to the organization of science in the United States at a massive scale centered around chemistry. Same thing in Germany. And then during the interwar years, even more chemicals were discovered and weaponized, and there were many chemical weapons that were tweaked to make them into insecticides, many insecticides tweaked to make them into chemical weapons.”
During World War II, the discovery and use of some really important new chemical classes arose, he says. Among them are the organochlorines, with DDT being the first and most important. DDT and similar chemicals were used to kill insects that are vectors of diseases.
“Their insecticidal properties were discovered by Paul Müller in Switzerland in 1939 and started to be used during the war years, especially by the United States to fight yellow fever and malaria and typhus in the various war theaters,” Frank says.
In Germany, Nazi chemist Gerhard Schrader discovered organophosphate insecticides as well as the German nerve gases. “The first of these was tabun and then a year later sarin, but it turned out not only were these super important and deadly — the deadliest war chemicals ever developed until that point — but they also could be altered to make really effective insecticides.
“So right after World War II, these were all commercialized at a massive scale. And DDT was used all over the world in incredible quantities, especially in the United States, for everything, from making beaches free of flies to making amphitheaters free of flies for concerts. I mean, you name it.”
U.S. Honest John missile warhead cutaway, showing M134 Sarin bomblets (c. 1960)
DDT and ‘Silent Spring’
The wide use of DDT and the uncovering of its ill effects on the environment and human health became the driving subject matter of “Silent Spring,” Rachel Carson’s pivotal book that spurred the popularity of the environmental advocacy movement.
In 1948, Life magazine ran a photo of model Kay Heffernon holding a hot dog and drinking a Coke on Jones Beach on Long Island, New York, while standing in a cloud of DDT. This was done to tout how “safe” DDT is.
When I was a kid in the 1960s, I was among the youth who ran behind the mosquito-killing fog trucks that drove around Miami. We would play in the pesticide clouds. There were also planes that would fly at low altitudes and disperse pesticides.
While it was popular, DDT was even sprayed on airplanes themselves, impregnated into wallpaper, added to paint and put in children’s nurseries.
“All of this led to the massive wildlife die-offs and pollution of the environment that drew Rachel Carson into the story,” Frank says. “So it’s all tied together: the back and forth between chemical weapons and pesticide development that then led to the most massive use of chemicals ever into the biosphere, incredible damage to wildlife and the emergence of the environmental movement starting in the 1950s, and then really coming out strongly in the 1960s.”
The chemical companies went after Rachel Carson ferociously, which backfired on them.
“A consortium of the biggest chemical companies organized themselves into a group to attack ‘Silent Spring,’” Frank says. “They threatened to sue her publisher if the book came out — they tried to stop it from being published. And then once it was published, they belittled her and her work saying ‘she’s not a real scientist, she’s a spinster, she doesn’t know what she’s talking about.’ And the result of all that is it led to a lot of attention and controversy such that CBS ended up doing a two-part story on, ‘Are we really facing a lot of pollution from these pesticides or not?’ And she came out on top of that debate between her and the chemical industry scientists.”
Frank says he believes Rachel Carson, who died in 1964 of cancer, would have been disappointed by what happened next. Organochlorine pesticides such as DDT were banned in the United States in 1972, and then throughout the world after that, but they were replaced by organophosphate insecticides that are more dangerous to handle.
“They lead to much higher rates of fatalities among farmworkers, but they break down in the environment faster,” Frank says of organophosphate insecticides. However, the compounds leave less residue on food, so they were the DDT replacement of choice.
“Because pests evolve resistance so quickly, we always have to use new chemicals and more of them,” Frank points out. “So by the late 1990s, we were using about twice the volume of pesticides in the United States than were in use when ‘Silent Spring’ came out.’”
Spraying hospital beds with DDT, PAIGC hospital of Ziguinchor, 1973. (Photo credit: Roel Coutinho, CC BY-SA 4.0)
Why ‘Silent Spring’ Resonated
In “The Chemical Age,” Frank explains why Rachel Carson was so popular, why she got so much attention and how “Silent Spring” struck a chord. He says it was a convergence of many forces that made that moment special.
“Rachel Carson was a brilliant writer and she had already written several best-selling books on the sea that just captured the imagination and allowed readers to feel like they were along the seashore, under the sea, really understanding the ecology of the oceans,” he says. “And then she decided to tackle this problem of pollution of the environment with pesticides, with DDT being the most important of those. And initially, she was actually reluctant to tackle this problem. She thought maybe she would just do an article for Reader’s Digest or some kind of magazine on it.”
She was encouraged by friends: “This is a very important topic. You really should do a book on this.” So she started doing research and she realized that a lot of things were happening all at once that made the timing right.
One of those things was the scare of nuclear war. Air-raid sirens and fallout shelters were a part of life in the 1950s.
“That was a time when there were widespread atmospheric testing of nuclear weapons, and one of the things that was discovered just before her book came out is that radioactive isotopes were showing up in baby’s teeth,” Frank says.
Parents were experiencing first-hand how environmental damage can affect their children.
DDT was also found to persist in the human body. DDT is fat soluble, so it builds up in body fat. In the 1960s, the average nursing mother in the United States had levels of DDT in her breast milk that were four times higher than the levels legally permitted in cow’s milk, Frank says.
And just a little bit before “Silent Spring” came out, the thalidomide disaster occurred. Drug companies were promoting thalidomide to women who were worried about miscarriage. The drugmakers said thalidomide could promote gestation.
“But it turned out that thalidomide caused horrific birth defects: children born with limbs in the wrong places, missing limbs, entirely — all kinds of awful birth defects, high mortality and so on. And so there were various things that were shaking confidence,” Frank says.
Fortunately, thalidomide was never federally approved for pregnant women in the United States, though it was used regularly in Europe before it was pulled from the market.
Another event that helped Rachel Carson’s message take hold was the Cranberry Scare during the presidential race between John F. Kennedy and Richard Nixon.
“There was a pesticide in use against pests of the cranberry crop, and some of the farmers used it illegally too close to the harvest of the crop so it showed up in the cranberries just before Thanksgiving,” Frank explains.
The cranberries were pulled from shelves prior to the holiday, and it became a major political issue.
“Everybody should read ‘Silent Spring,’” Frank says. “It’s one of the most important books ever published. Probably in the environmental era, the most important book ever published. One of the things you’ll notice is that Rachel Carson talks about radioactive fallout before she talks about pesticides. That was a purposeful literary technique in order to draw the reader into something they’re already very concerned about and make parallels with what we were doing with chemical pollution of the environment.”
Rachel Carson talked a lot about the right to know and the right to decide while the government was carrying on ineffective aerial spraying programs to kill the fire ant in the South and the spongy moth (Lymantria dispar, formerly known as the gypsy moth) throughout the country.
“They didn’t actually destroy the pests they were targeting, but they did manage to wipe out huge amounts of wildlife,” Frank says.
On Long Island in New York State, a group of organic gardeners sued in the 1950s over aerial spraying and took the case all the way to the U.S. Supreme Court. “They failed in the Supreme Court, but they won in the court of public opinion,” Frank says.
The group on Long Island formed the Environmental Defense Fund, which brought DDTs lawsuits throughout the country, and other environmental groups followed suit.
“The environmental movement, it existed, it was strong before Rachel Carson, but it wasn’t a widespread public movement until ‘Silent Spring,’” Frank says. “She was the one who gave voice to it and let people understand that they were getting poisoned in their own homes without their consent and without their benefit, at the same time as it was destroying wildlife around the country. That galvanized the movement.”
Rachel Carson, the author of “Silent Spring, in her 1940 U.S. Fish and Wildlife Service employee portrait.
Why DDT Was so Prevalent
DDT is easy to synthesize and wasn’t patented since it was a product of the war effort, so it’s no wonder it became so widespread.
There were thousands of garage operations of people like chemistry teachers making DDT and selling it in little batches.
“It started out as a powerful public health tool. And in fact, if we go back to World War II, not only were we using it to wipe out the insect vectors of malaria, which is Anopheles mosquito, and of yellow fever, Aedes aegypti mosquito, but we were also using it to fight typhus,” Frank says. “And typhus is a disease of famine and war. It’s the accompaniment of famine war. It’s what killed the Irish. It’s what killed people in trenches. And when the United States and Allied forces were making their way up through Italy fighting the Nazi regime and going up the Italian peninsula, when they got to Naples, there was a typhus outbreak in Naples.”
In war, historically, disease has killed more soldiers than weapons. But Frank says that changed during World War II thanks to public health tools like DDT, antimalarial drugs and improved surgical antiseptic techniques.
“Before that, people were, in every war, killed more by disease than by bullets,” he says.
Neapolitans had been sheltering in caves by the tens of thousands in crowded, dirty conditions where lice proliferate. The body louse is the vector of typhus, so typhus spread among the Neapolitans as the lice did.
The U.S. military and the Rockefeller Foundation set up sanitary stations in Naples and sprayed every person with DDT powder and stopped typhus in its tracks.
“It was actually the first time in human history that a typhus epidemic was stopped,” Frank says. “So it was this very powerful, important public health tool during the war, but then its massive overuse after the war led to the evolution of resistance by the pest such that it was no longer useful.”
DDT lost its standing as an important public health tool once DDT-resistant lice emerged.
“If DDT had only been saved for public health emergencies of a typhus outbreak or malaria outbreak, it would still be effective today,” Frank says. “But as people, we just can’t stop ourselves from overusing any tool that comes along and then making it useless, which is what has happened to pesticide after pesticide.”
A U.S. soldier is demonstrating DDT hand-spraying equipment. DDT was used to control the spread of typhus-carrying lice. (Photo credit: CDC)
Agents of Global Change
Climate change is an agent of global change that, now, everybody’s aware of, Frank says, but he points out that there is also nitrification and chemical pollution of the biosphere.
“We clearly are on an unsustainable path, and we have to go to sustainable practices, including organic farming at a big scale,” Frank says. “We know how to do it. Even with small applications of pesticides with Integrated Pest Management, it can be done quite effectively.”
It can even be achieved with no pesticides whatsoever if we stop growing monocultures, he adds. Using varieties of crops and different seed varieties are the kinds of solutions that we need, and diverse gardens and diverse farmlands that rely on biological control — not synthetic chemical agents.”
Frank’s Personal Connection to the Chemical Age
Frank is from Alaska where he grew up on an 80-acre organic farm that grew hay, potatoes and other crops and raised pigs. “We were actually the only Jewish pig farmers in Alaska,” he says.
The motivating force for Frank to write “The Chemical Age,” he says, is that some of the players are his direct ancestors and he grew up hearing many of the stories in the book.
“I’m actually a first-generation American,” he says. “My father was born in Germany and my mother in Austria, and they were both Jewish refugees from the Nazis in World War II. My father’s father was not Jewish; that’s where my name, von Hippel, comes from, but he was a prominent physicist [and] material science designer.”
When his grandfather, Arthur von Hippel, and his family fled the Nazis, they initially went to Turkey, where they stayed for a little over a year before moving to Denmark. There, his grandfather ended up in the lab of Danish physicist Niels Bohr and was hired by MIT to develop a material science lab in which he developed the dielectric materials that were instrumental in radar. He also made crystals for American military radios and synthetic materials for uniforms that wouldn’t break down in the jungles of Southeast Asia.
On the other side of Frank’s family, his maternal grandfather’s father was James Franck, a Nobel Laureate in physics. “By the time the Nazis rose to power, he was leading the physics institute that was one of the two in Germany, and he resigned his institute directorship in protest of the antisemitism of the Nazis,” Frank says.
Franck would go on to work in Niels Bohr’s lab and later immigrated to the United States.
“He was in charge of the chemistry division of the Manhattan Project for the U.S. war effort during World War II,” Frank says. “So these major physicists and chemists from the World War I, World War II era, they were people that my father vacationed with as a kid.” For example, on one trip to Niels Bohr’s vacation cottage, they stayed with Edward Teller, the father of the hydrogen bomb.
His great-grandfather’s mentor was Fritz Haber, the German chemist who discovered nitrogen fixation and how to fix atmospheric nitrogen using high pressure and high temperature to make artificial fertilizers.
“That discovery of being able to take nitrogen out of the atmosphere to make artificial fertilizers is credited with probably saving a couple of billion lives during the 20th century from starvation, but he’s also the father of modern chemical warfare,” Frank says.
Grounds for Optimism
Frank says there are a lot of grounds for optimism, including the enthusiasm of the younger generation.
“There’s so much enthusiasm in that generation to solve these pressing problems — a lot of attention on climate change, and that’s warranted, but also other environmental problems,” he says. “And they’re all really tied together. If we’re solving climate change, part of the solution is to preserve the tropical rainforest. In my opinion, the biggest crisis we’re facing is the global loss of biodiversity, and there’s no better way to save biodiversity than preserving intact habitats.”
“The Chemical Age” by Frank von Hippel.
I hope you enjoyed my conversation with Frank von Hippel on the history of agricultural chemicals. If you haven’t listened yet, you can do so now by scrolling to the top of the page and clicking the Play icon in the green bar under the page title.
Have you quit using chemicals in your garden? Let us know in the comments below.
Links & Resources
Some product links in this guide are affiliate links. See full disclosure below.
Episode 008: Organic Pest Control with Jeff Gillman
Episode 050: Organic Pest Control: Beneficial Insects and Beyond
Episode 121: Fire Ant Control: The Down and Dirty on Identification, Behavior and What to Know
Episode 184: More Must-Have Books for Every Gardener
Episode 195: Identifying and Controlling Garden Pests Organically
Episode 219: Troublesome Garden Pests: Organic Control Strategies That Work
Episode 222: Tiny Vampires: Understanding Mosquitoes & Effective Mosquito Control
joegardener free resource: 10 Common & Destructive Garden Pests: Prevention & Control
joegardener Online Gardening Academy™: Popular courses on gardening fundamentals; managing pests, diseases & weeds; seed starting and more.
joegardener Online Gardening Academy Organic Vegetable Gardening: My new premium online course membership opens in 2023. Sign up for the waitlist here.
joegardener Online Gardening Academy Beginning Gardener Fundamentals: Essential principles to know to create a thriving garden.
joegardener Online Gardening Academy Growing Epic Tomatoes: Learn how to grow epic tomatoes with Joe Lamp’l and Craig LeHoullier.
joegardener Online Gardening Academy Master Pests, Diseases & Weeds: Learn the proactive steps to take to manage pests, diseases and weeds for a more successful garden with a lot less frustration. Just $47 for lifetime access!
joegardener Online Gardening Academy Perfect Soil Recipe Master Class: Learn how to create the perfect soil environment for thriving plants.
Science History Podcast on Apple Podcasts
Science History Podcast on Spotify
Science History Podcast on Twitter: @sci_history
“The Chemical Age: How Chemists Fought Famine and Disease, Killed Millions, and Changed Our Relationship with the Earth” by Frank von Hippel
“Silent Spring” by Rachel Carson
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Disclosure: Some product links in this guide are affiliate links, which means we get a commission if you purchase. However, none of the prices of these resources have been increased to compensate us, and compensation is not an influencing factor on their inclusion here. The selection of all items featured in this post and podcast were based solely on merit and in no way influenced by any affiliate or financial incentive, or contractual relationship. At the time of this writing, Joe Lamp’l has professional relationships with the following companies who may have products included in this post and podcast: Rain Bird, Corona Tools, AeroGarden, Milorganite, Soil3, Greenhouse Megastore, PittMoss, Territorial Seed Company, Earth’s Ally, National Wildlife Federation and TerraThrive. These companies are either Brand Partners of joegardener.com and/or advertise on our website. However, we receive no additional compensation from the sales or promotion of their product through this guide. The inclusion of any products mentioned within this post is entirely independent and exclusive of any relationship.
