Patricia DeMarco, Director of the Rachel Carson Institute at Chatham University, has heard the question before.
Has history—and science—proven that Springdale, Pa., native Rachel Carson was right in her book, “Silent Spring”? Not just about the most celebrated of her attacks—the impact on the environment of the widely used herbicide DDT—but the other big-picture points she made in her now-classic treatise that was first published 50 years ago this fall:
That the chlorinated hydrocarbons such as DDT, heptachlor, chlordane and aldrin truly were persistent and stayed in the environment, causing long-term, unexpected damage? That insects and weeds were developing resistance to the herbicides and pesticides and that man would have to turn to natural-based defenses to try to lessen their impact? That man would see cancers rise as a result of our use of these chemicals and others?
“A lot of detractors like to go back and ask, ‘Was Rachel Carson wrong?’” DeMarco said. “Especially when it was something little understood then, like cancer. I mean, the structure of DNA wasn’t even discovered until 1963. People often are criticizing things she could not have even known about then.”
But 50 years after Carson, who died in 1964, was mocked in a Monsanto company magazine, subjected to a $250,000 distortion campaign by the National Agricultural Chemical Association, and dismissed by then-Agriculture Secretary Ezra Taft Benson as “probably a Communist,” the attacks against her and her book rage on—even if they’re less breathless, most of the time.
“Because I’m her most conspicuous biographer, I get emails and letters that say, ‘She’s a baby killer,’ ” said Linda Lear, author of “Rachel Carson: Witness for Nature.” “The comments about her are still very virulent.”
The Competitive Enterprise Institute, a libertarian organization, doesn’t call Carson a “baby killer,” but it does believe she is responsible for millions of deaths because the ban on DDT led to more deaths in Africa and Asia in particular. “We’d argue she was wrong and we’ve documented why,” said Angela Logomasini, a senior fellow for the institute, which put up the website Rachelwaswrong.org to make their point. “We debunked what she claimed was true.”
Some former critics have changed their tune over the decades.
CropLife America, the renamed National Agricultural Chemical Association, which spent so much money trying to muffle “Silent Spring” in 1962, now takes a different tack. Looking back at how the National Agricultural Chemical Association treated Carson and her book in 1962, “the only thing that counts is what was on the record, and it’s not very pretty compared to the approach we use now to engage and listen first,” said Jay Vroom, CropLife America’s president and CEO.
While saying he generally agreed with many of Carson’s points in “Silent Spring”—including that DDT was overused—Vroom said, in contrast to his organization’s defiant stance in 1962: “I don’t believe asking if Rachel Carson was right or wrong is the correct question because none of this is black and white.”
But champions of Carson, of course, believe it is. They pose the question to show readers or listeners how prescient she was—even if they like to debate exactly how to describe her work.
“Prescient—I don’t like that word to describe her; it seems supernatural,” said Sandra Steingraber, ecologist and author of “Raising Elijah: Protecting Children in an Age of Environmental Crisis.” “I like to say she was just super smart and put all these pieces of the puzzle together.” Steingraber spent four years trying to assess Carson’s findings for her prior book, “Living Downstream,” “...and I continue to be impressed by her account from 50 years ago. People who say Carson was wrong I put in the same category as the tobacco industry who, from 1950 to 1990, said there was no connection between smoking and cancer because some studies said yes, and some studies said no,” she said. “They created doubt until 1996 when scientists found the chemical that linked them. [The tobacco industry] found themselves standing on an ever-shrinking island.”
Mark Madison, historian for the U.S. Fish & Wildlife Service, for which Carson worked before she wrote “Silent Spring,” said Carson’s historical record is mixed. “The answer is she was right about some things, we don’t know about some other things, and she was overly optimistic about biological controls,” he said, referring to Carson’s hope that nature-based solutions could be developed to replace all chemical herbicides and pesticides.
But the question remains: Was Rachael Carson right?
"All these facts… caused Food and Drug Administration scientists to declare as early as 1950 that it is ‘extremely likely the potential hazard of DDT has been underestimated.’ There has been no such parallel situation in medical history. No one yet knows what the ultimate consequences may be.”
—Silent Spring, chapter 3, page 23
Carson never called for the outright banning of DDT, the first widely used synthetic pesticide initially used just prior to World War II to control malaria and typhus and eventually expanded to agricultural use.
However, with her explanation of how it works, its persistence in the environment, telling how biological magnifiers increase the amount that is stored in human and animal bodies, and the stories in “Silent Spring” about the impact of DDT on wildlife, water and soil conditions, Carson’s work is credited by many in leading directly to the U.S. ban of its use in 1972—a ban that spread quickly through much of the world.
To Carson supporters, the ban itself is proof that she was right about DDT’s impact in “Silent Spring” because DDT is still found in the environment today. “I think DDT is an awful chemical,” said Lear, who created the website rachelcarson.org to celebrate her subject. “It’s in every mother’s milk, even 40 years after it was banned, and it’s in every Arctic bird. And we still don’t really know what the long-term effects are, but we know it’s not pleasant.”
Opponents see the ban as proof of what they consider her misguided efforts.
“Millions of people—mostly in Africa—died because they completely banned it,” said Logomasini of rachelwaswrong.org. “In Sri Lanka they got malaria deaths down to single digits, and after the ban of DDT it went quickly back up to thousands.”
But in examples that Carson discussed in “Silent Spring,” the reason that DDT was no longer being used in some places for malaria was because mosquitoes had quickly developed a resistance to the insecticide. And DDT continues to be allowed for targeted malaria control, primarily in direct application in homes, supporters point out.
“She saw (resistance) happening then,” said Diana Post, president of the Rachel Carson Council, an environmental organization based in Carson’s former adult home in Silver Springs, Md. “And when they used low levels of DDT occasionally, they could get results without killing the beneficial insects, and get the same results as high levels of DDT that killed everything. She said then this might be the way to go.”
Even CropLife America, which so vehemently disagreed with Carson in 1962, now finds merit in her belief that DDT was, at a minimum, being overused. “No doubt about it,” Vroom, CropLife’s CEO said. “She was absolutely right. Why more people weren’t articulating that before her, I don’t know.”
"One of the most important things to remember about insecticides in soil is their long persistence, measured not in months but in years.”
—Silent Spring, chapter 5, page 57
While it might seem that at least on this one issue it would be easy to find agreement—studies routinely find traces of chlorinated hydrocarbons in soil, the bodies of land and aquatic creations, even human umbilical cord blood decades after the chemicals were last used—opponents still take issue with it.
“They say DDT is persistent,” Logomasini said. “But there’s evidence it does dissipate over time.” More important than whether it dissipates or not, Logomasini said, is the “hazard level” of that chemical. Carson “just sort of made a very blanket statement about chemicals and their persistence. But you have to look at its hazard level and how much of it will have an impact.”
To Vroom of CropLife, the issue of persistence is clearly settled. “As a general example, she was right to sound the alarm of the buildup of chemicals. We’re still living today with DDT.” It’s a problem, he said, that “there aren’t any places in the U.S. where you can’t find traces of DDT.”
Post, of the Rachel Carson Council, points out that DDT is so persistent that the U.S. government even gives certified organic food growers a waiver for the presence of DDT on their produce “because it’s unavoidable in certain places.”
Most troubling to Carson backers is the evidence that the agro-chemical industry continues to make claims about the persistence of chemicals that are found wanting, said Ken Cook, co-founder of the Environmental Working Group.
When the chemical company Monsanto created Roundup, the popular herbicide, in 1973, it said its active ingredient, glyphosate, broke down quickly in the environment and would not be a persistent threat to the environment.
But a U.S. Geological Survey study did air, water and soil samples around the country “and Roundup was found in almost every sample,” Cook said. Now scientists are trying to figure out if the low-level presence of Roundup throughout the environment is potentially harmful.
“It’s amazing,” Cook says about “Silent Spring.” “You can pick up that book today and find lessons we can still use in every chapter.”
"The world has heard much of the triumphant war against disease through the control of insect vectors of infection, but it has heard little of the other side of the story—the defeats, the short-lived triumphs that now strongly support the alarming view that the insect enemy has been made actually stronger by our efforts. Even worse, we may have destroyed our very means of fighting.”
—Silent Spring, chapter 16, page 266
Carson was aware, even in 1962, of the ability of insects—and even weeds—to develop resistance to pesticides and herbicides. While her focus in the book was on the ability of insects to build up resistance, more recently the phenomenon has been the specter of weeds that develop resistance.
“It’s the same story Rachel Carson was telling,” Cook says. “It’s the resistance story all over again. Literally dozens and dozens of weeds have become resistant to Roundup,” which is the most popular herbicide in the United States. “And because we’ve overused glyphosate, now Dow [Chemical Co.] has petitioned for a new 2,4-D-resistant corn.”
The herbicide 2,4-D is one of the most popular herbicides in the world and was one of the active ingredients in the Vietnam-era defoliant Agent Orange. Environmental concerns resulted in reduced use of of 2,4-D over the years, but it was never banned as DDT was.
Vroom said that since the 1980s, companies like Dow Chemical and DuPont have done a better job of creating targeted herbicides and insecticides that take resistance into consideration by trying to use natural processes to drive away or kill pests and weeds, rather than create synthetic chemicals.
“All of these products are kinder, gentler and more targeted, and have the challenge of managing so the pests you’re trying to control don’t develop resistance more quickly,” he said. “The only time agriculture gets in trouble is when things get too simple and we think we have the silver bullet for our problem. What I see is a much more science-based approach.”
"Many of the chlorinated hydrocarbons, the phenols, and some herbicides interfere with oxidation and energy production within the cell. By these means they may be creating sleeper cancer cells in which an irreversible malignancy will slumber long and undetected until finally—its cause long forgotten and even unsuspected—it flares into the open as recognizable cancer.”
—Silent Spring, chapter 14, page 232
Nothing heats up the debate over “Silent Spring” quicker than examining Carson’s conjecture that the surge of chemicals that were being put into the environment would lead to an explosion of cancer in humans.
“The cancer to chemical tie is tenuous,” Logomasini said. “Cancer is a disease of aging and we’re all going to get it if we live long enough.”
But the numbers game also gets played on this issue. If you want to prove Carson’s point, you can look at cancer detection rates, which have risen in humans. But if you want to oppose it, you look at cancer death rates, which have fallen because medical science has gotten so much better in the last 50 years of treating, if not outright curing, many cancers.
“The rates did rise for many years,” Cook points out. “But we still have trouble proving that certain exposures lead to cancer.”
Madison, the Fish & Wildlife historian, agrees, noting that Carson herself knew in 1962, as in 2012, that directly proving a link between persistent, low levels of exposure to slow-acting chemicals and cancer in humans would always be difficult, unlike some of her other more readily proved points. “Making those direct connections [to cancer] is extremely difficult, whereas measuring DDT in eagles is easy,” he said.
Lear, Carson’s biographer, concedes that Carson may not have been exactly right about cancer but points out that the kind of data she was working with in 1962 wouldn’t have helped anyway. “Did they have the final data then? No. She couldn’t get tapes [of data] on the disease,” she said. But the larger point about Carson’s fears about cancer is also true of the rest of the book, Lear said. “My take has been that this was a warning. It’s not a finished take.”
Sean Hamill is a reporter for the Pittsburgh Post-Gazette.