The Truth About Dioxin
Despite a slew of reassuring newspaper stories about dioxin, scientific studies are finding that the chemical is even worse than once thought
Imagine a family of toxic chemicals so widespread that no one can escape exposure, industrial compounds that at low doses can disable the immune system, promote cancer and other diseases-and even cross the placental barrier to disrupt embryonic development. Now consider that these chemicals are real. And that the U.S. Environmental Protection Agency (EPA) is releasing this summer a draft of a reassessment of of their measurable effects, with results so worrisome that the agency is expected to recommend tight future controls on the chemicals.
Given all that, the the EPA's expected tough stance would seem to be reassuring news. Yet convincing the public of the need for costly controls may not be easy. That's because during the past three years, newspapers and magazines around the country published numerous stories overlooking the science involved and discounting the danger of exposure to the most toxic substance in the group: 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), commonly known as dioxin.
Where have those stories come from? And who's right? The answers serve as a wake-up call to journalists and editors - and could change the way you read the newspaper.
Nearly everyone living in industrialized society has been exposed to dioxin. The chlorine-based chemical is an unwanted by-product of the manufacture of chlorine-bleached paper, herbicides and other products, including some household cleaners. Dioxin also can enter the air in diesel exhaust and in fly ash from incinerators (especially from the burning of hospital waste). The chemical also has been found in rivers downstream from paper mills and other factories that use chlorine compounds.
Until the summer of 1991, news stories generally referred to dioxin as the most dangerous of man-made chemicals. Its discovery on local roads had completely closed down the town of Times Beach in Missouri. Its detection in rivers and fish has been cause for alarm. When 1988 tests found dioxin in Florida's Fenholloway, for example, activists posted a warning sign (dioxin is no longer detectable in the water).
In the laboratory, dioxin had induced cancer in animals at far smaller doses than any other cancer-causing chemical, and it had proved to be more than 11,000 times more potent than the deadly poison sodium cyanide in killing guinea pigs.
Then, on August 15, 1991, New York Times reporter Keith Schneider wrote a front-page story with the assertion that exposure to dioxin "is now considered by some experts to be no more risky than spending a week sunbathing," suggesting that pollution-control requirements for the chemical could be relaxed. At least 20 major newspapers around the country reprinted the story from The New York Times News Service. And, following a tradition of taking cues from the Times, other papers ran their own similar reports and editorials that lambasted scientists for encouraging the government to waste money on dioxin cleanups.
Despite the flurry of attention, Schneider's conclusions about dioxin's risks, then and in other stories for nearly three years, had a major flaw: They were wrong. Many experts in and outside of the federal government have said all along that there has been no scientific basis for suggesting that dioxin is less dangerous than previously thought. "I don't think we have any indication right now that the risks would be lower than we believed," said William Farland, one of the EPA officials in charge of the reassessment of dioxin, in 1992. But Schneider continued to downplay dioxin's dangers and overlook research until a May 11, 1994, story about the EPA reassessment.
In a story on September 26, 1992, Schneider reported that an independent panel of scientists assembled by the EPA concluded at a meeting that dioxin is not a large-scale cancer threat except to people exposed to "unusually high levels" in factories or from accidents, and that "the risk to average Americans exposed to dioxin . . . is lower than previously believed."
Other reporters who attended the meeting came away with a markedly different interpretation. Newsday's Earl Lane reported that the panel, which reviewed drafts of the EPA reassessment of dioxin, had found "that the chemical's effects may be broader and more troubling than previously thought." Three weeks after the conference, Wall Street Journal reporter Rose Gutfeld wrote that the panel's findings expressed concern that "the danger from dioxin may be broader and more serious than previously thought."
In interviews conducted by this writer after The New York Times story appeared, several scientists on the panel called Schneider's article "very inaccurate." Says Claude Hughes, a toxicologist and fertility specialist at Duke University Medical Center, "Frankly, it was pretty bad journalism. It was not a valid summary of the meeting."
Even so, Schneider's September 26 story was also picked up by other newspapers, including The Kansas City Star, which put it on the front page under the headline "Scientists Say Dioxin Is No Big Threat." Four days later, a correction acknowledged that the headline "might have understated the potential effects" of dioxin. The next week, reporter Michael Mansur wrote that while dioxin's risks remain uncertain, "there are new reasons to be concerned."
Eric Adler, a science writer at The Kansas City Star, points out that when the Times makes a pronouncement on its front page, journalists everywhere take it seriously, in part because the Times has such a strong reputation for accuracy. "It takes a cool-headed editor and adroit reporters to question the Times' conclusions," Adler says.
The hazards of dioxin were first identified in herbicides in the mid-1950s, but the chemical didn't become a household word until Vietnam War veterans claimed a link between post-war health problems and Agent Orange, which contained dioxin. Among the defoliant's several toxic compounds, dioxin was by far the most powerful, according to the National Academy of Sciences and the National Cancer Institute.
Meanwhile, a major dioxin-related health problem surfaced in the United States during the early 1970s. A waste hauler sprayed oil contaminated with the chemical on unpaved roads, in trailer parks and on fields at 27 locations in eastern Missouri where unsuspecting customers wanted to hold down dust.
More than 50 quarter horses at Shenandoah Stables near Moscow Mills, Missouri, died. Their practice arena had been sprayed with the tainted oil. Soon after, there were news reports of hundreds of dead wild birds, chickens, dogs and cats in the area. Within days, the stable owner's six-year-old daughter was rushed to the hospital, bleeding and crying in pain. Her bladder was severely inflamed, and she had diarrhea, headaches and aching joints. Investigators from the federal Centers for Disease Control (CDC) identified the cause: dioxin.
In 1982, the CDC found some of the highest levels of dioxin in the region in Times Beach. The federal government bought out the town's property owners, more than 2,000 people moved and the town closed down in early 1983 at a cost of approximately $30 million.
Vernon Houk, then an assistant surgeon general at the CDC, was one of the federal officials who recommended the buyout. In May 1991, however, Houk told a Columbia, Missouri, conference on environmental health that he believed Times Beach residents never should have been moved. Houk told this writer in early 1993 that new research was showing dioxin to be "not especially harmful to man." In April 1991, one month before Houk's speech, the EPA announced it would reevaluate dioxin's risks. The agency was aware that dioxin research was advancing rapidly, and the paper industry, believing new science would support more relaxed standards, pushed for the review.
Then, on August 15, came Schneider's front-page article, headlined "U.S. Officials Say Dangers of Dioxin Were Exaggerated," followed by the similar stories in newspapers around the country. "We wanted to have a big splash with it," Schneider explained in a 1992 interview. "We felt that the media coverage of this environmental issue needed to be reassessed. We need to be a lot smarter, because not everything is a disaster."
The favorite newsbite for many reporters was Schneider's sunbathing comparison. But most other news stories erroneously attributed the conclusion to scientists. On August 17, The Sacramento Bee reported that "a widening group of scientists" had "come to the conclusion that exposure to dioxin under most circumstances is no more dangerous than spending a week at the beach." An Associated Press story published in The Dallas Morning News on September 3 reported that "some studies have concluded that the effects of dioxin are no worse on the body than a week of sunbathing."
Months later, on December 3, another New York Times reporter, covering a lawsuit, wrote that "some experts now say that exposure to the chemical is no more risky than a week of tanning." And more than a year later, on October 14, 1992, Financial Times reporter Peter Knight wrote that "last year a U.S. report described the danger from dioxins as no more harmful than a week of sunbathing."
All of the articles and editorials should have attributed the sunbathing quote to Schneider, who says he and his editors came up with the analogy by reviewing charts of risk factors for other hazards. "It was my metaphor," Schneider said in a 1992 interview with this writer. "But I ran it by Houk and two other epidemiologists, and they agreed." Other scientists, however, strongly disagree. "I still think it's absurd," says Richard Clapp, a professor at Boston University's School of Public Health, who has studied dioxin and other health risks. Even Houk, who recently retired from CDC, said the analogy is inappropriate. "I don't know what a week of sunbathing exposure would do," he said in 1993. "I don't think those comparisons make very much sense, because people don't understand them."
While there is legitimate debate over the exact degree of risk dioxin poses, no scientists contend that dioxin is safe. Cancer is still a major concern, but even more troubling are new studies showing other adverse effects. Researchers at the EPA and at university laboratories in several countries have found persuasive evidence-in animals and humans-that even tiny amounts of dioxin can skew critical chemical balances that are necessary for normal growth, especially in developing embryos.
EPA's chief researcher on the dioxin reassessment, toxicologist Linda Birnbaum, explains that cells respond to dioxin as if it were a hormone sending wrong messages. The confused cells keep dividing when they should stop, fail to grow when they should continue or turn into different types of cells altogether. "Dioxin is a very potent growth dysregulator," Birnbaum says.
A Dutch study published in November 1993 found that infants exposed to dioxin from their mothers' breast milk produced excess thyroid hormones, which could retard development of the central nervous system and cause psychomotor problems. Two years earlier, the same group of researchers at the University of Amsterdam discovered a relationship between intracranial bleeding in newborn babies and high levels of dioxin exposure before birth. The researchers think the mothers were exposed to dioxin in much the same way everyone in industrialized countries is exposed-primarily through contamination in food.
A 1993 University of Heidelberg study reported that people who ingested high doses of dioxin in vegetables grown on contaminated soil suffered verbal and psychomotor problems, irritability and emotional instability. The symptoms mirror cognitive deficits found in dioxin-exposed monkeys and other animals.
Other studies also find evidence that humans and study animals react to dioxin in similar ways. The EPA's Birnbaum points to an ongoing National Institute of Occupational Safety and Health (NIOSH) study of workers exposed to high levels of dioxin. Men in that study and rats in other research show comparable decreases in levels of circulating testosterone in response to dioxin. Increases in cancer found in the NIOSH study are also very close to the rate of cancer among animals exposed to comparable levels of dioxin, she says.
Birnbaum's observations are echoed by other scientists, including George Lucier of the National Institute of Environmental Health Sciences (NIEHS), who has done pioneering work in comparing animal studies with human responses to dioxin and other dioxinlike chemicals, such as polychlorinated dibenzofurans (PCDFs). Because PCDFs andcertain polychlorinated biphenyls (PCBs) molecules are the same size and shape as dioxin molecules, they attach to the same cellular receptors in the body and produce the same spectrum of toxic effects, although they are less potent than dioxin. "So what we learn about PCDFs is relevant to understanding dioxin's toxicity," he says.
In Taiwan, women who ate rice oil contaminated with PCBs and PCDFs in 1979 gave birth to children who suffered developmental delays and growth retardation; their IQs averaged 5 points below normal. Researchers are finding that many of the boys, who are just reaching sexual maturity, have abnormally small penises.
EPA's dioxin reassessment panel hasconcluded that the combined effects of all dioxinlike chemicals must be considered in evaluating dioxin's risks. Even the small amounts of these chemicals that most people have in their bodies may be enough to trigger developmental or immunological effects. According to Birnbaum, the current dietary intake of dioxin and closely related compounds may be "very close" to the danger zone. "If current human levels are at or near the point where effects are occurring, that means we don't have any kind of margin of safety," she says. "And there certainly are people in the population who are way above that level."
In a September 1993 letter to the American Journalism Review, Times reporter Schneider wrote that "there is considerable human epidemiological data on dioxin that doesn't indicate that the chemical has produced immunological effects, reproductive harm or depressed immune systems, according to scientists who have reviewed the studies. The most authoritative study done on dioxin, prepared by NIOSH and published in 1991, did not find such effects."
That NIOSH study, however, could not have found those effects, because it did not look for them. It analyzed only cancer mortality, finding a 46 percent increase in cancer deaths among men exposed to dioxin for longer than one year. Their exposure took place at least 20 years (the average latency period for most cancers) before the study. NIOSH is now analyzing data on immune system and reproductive effects of dioxin. An early finding, published in spring 1994, is that men with high exposures to dioxin show a significant, though small, decrease in testosterone levels.
Schneider stands by his reporting. For this article, he referred all questions to New York Times assistant national editor Carl Lavin, who said he saw no point in discussing the subject with this writer because, he said, "your reporting on this [for a previous story] has not been fair or accurate."
"We've never said in The New York Times that dioxin is not dangerous," Schneider told a group of journalists last fall at a conference. He told this writer in the spring of 1993 that his conclusion in a March 21, 1993, article that "new research indicates that dioxin may not be so dangerous after all" refers only to dioxin's cancer-causing potential, not other health effects. The article, however, fails to make that point.
On May 11, 1994, Schneider reported in the Times that he had obtained a draft of the EPA reassessment, and for the first time he detailed studies showing dioxin's effects on developing embryos and on the immune and reproductive systems. But as for cancer, he wrote that the draft "called into question dioxin's reputation as a deadly killer of people." According to Lynn Goldman, EPA assistant administrator for prevention, pesticides and toxic substances, nothing in the draft supported that observation. "It's not in there," she said in May. The report reaffirms that dioxin is a probable cause of cancer in humans.
Whether or not its cancer risk is less than once thought, according to CDC health scientist Mark McClanahan, dioxin is the most potent cancer-causing chemical ever tested. It is thousands of times more powerful than most other chemicals that cause cancer in animals. Even the lowest cancer-risk estimates for rats suggested by industry studies rate dioxin nearly 2 million times stronger than benzene, one of a handful of known human carcinogens.
Vernon Houk, whose views on dioxin to have been controversial since the early 1980s, when the CDC began investigating Agent Orange health claims, once wrote that dioxin "may be without consequence even in very high dose exposure to humans." During a 1990 congressional investigation, Houk acknowledged under oath that he had written those words in a letter urging Canada to relax dioxin standards. He is now too ill for interviews, but he told this writer last year, "No one in their right mind would make that statement. I clearly believe that dioxin is harmful at high levels."
Houk's views apparently were the basis for a New York Times editorial claiming that "federal officials now believe they may have overreacted in setting extremely low exposure limits for dioxin and in permanently evacuating all the residents of Times Beach." But Houk was not the official responsible for deciding when people should be moved from contaminated communities. Barry L. Johnson, administrator of the federal Agency for Toxic Substances and Disease Registry, which makes those decisions, says no reporters contacted him for a reaction to Houk's statement. Says Johnson, "Given the scientific information we have today, we would take exactly the same action."
Marilyn Leistner was mayor of Times Beach when the town was evacuated. "Our lives were not disrupted for no reason," Leistner says. "We had to move because dioxin was causing real health problems." She cites infants born with cancer and organs outside their bodies, adding, "All I can say is that I'd take a week in the sun anytime over moving back to Times Beach."
The late Rep. Ted Weiss (Democrat, New York), chairman of the House subcommittee that held hearings on dioxin in June 1992, accused the nation's leading newspapers of falling for an industry propaganda campaign to downgrade the contaminant's risks. "The industry's campaign is proof of an old maxim," Weiss said. "If you repeat a lie enough, people will start believing it."
The first mainstream news organization to report an industry role in the controversy was The Wall Street Journal. On February 20, 1992, it ran a front-page article by Jeff Bailey asserting that the reappraisal of dioxin "is as much a result of a well-financed public relations campaign by the paper and chlorine industries as it is a result of new research."
American Forest and Paper Association (AFPA) president Red Caveny will not confirm that the trade group is lobbying for relaxed dioxin standards. The AFPA's position, he says, "is to support the lawful right of individual states to determine their own standards." New regulations would surely be expensive. The AFPA estimates that member companies have already spent $1 billion reducing dioxin contamination. In a news release issued after a 1993 EPA proposal to cut dioxin emissions to unmeasurable levels, the AFPA expressed alarm that clean-up costs would force 33 mills to close, with a resulting loss of 21,500 jobs.
Schneider acknowledged he was aware of an industry push to weaken standards. "There are vested interests in all of this," he said in 1992. "For Green-peace, NRDC [Natural Resources Defense Council], Sierra Club and others who have been painting dioxin as the death toxin of the world, it means great public fear and fund-raising. And for an industry to paint it as the safest thing since Kool-Aid, it means billions of dollars in pollution control cost savings."
Representatives of environmental groups deny there's any benefit in exaggeration. "Our members hold us to the highest standards of good science and good common sense," says Sharon Newsome, vice president for Resources Conservation at the National Wildlife Federation. "We know that our credibility is our most precious asset."
In the first of a March 1993, five-part Times series on misguided federal environmental policies, Schneider spelled out his central thesis-that "billions of dollars are wasted each year in battling problems that are no longer considered especially dangerous." He cited only one example of a substance that "may not be so dangerous after all"-dioxin.
In an essay published last fall in the journal of the Society of Environmental Journalists, Schneider urged colleagues to be skeptical of environmental groups' agendas. He concluded, "When it comes to environmental protection, one of the gravest risks of all is misinformation masquerading as fact." In promoting the view that dioxin is a weak poison, Schneider has ignored his own advice.
He has also shaken the reporting community. In the same newsletter, USA Today environment editor Rae Tyson pointed out that healthy skepticism has always been part of good journalism. But, he wrote; "I think Schneider messed up. And not because he questioned a time-honored premise, but because he relied on some questionable science to prove his point." Therein lies a lesson for all who strive to understand the real environmental hazards of our world. So maybe the dioxin confusion can serve a purpose after all, for journalists and readers alike.
Maryland writer Vicki Monks first challenged newspaper reports on dioxin in the American Journalism Review in 1993.