Remembering the Children of Agent Orange: How Dioxin Damages Generation After Generation
Agent Orange took my father, and quite likely took my sisters. My story is frighteningly common. Part 3 in a series.
In the second part of this series, I described the catastrophic health struggles of the children of veterans who were exposed to Agent Orange. In this part, I go down a scientific rabbit hole to uncover how this could have happened, and discovered one of the most expensively and diligently studied — and perhaps most willfully obfuscated — environmental disasters in modern history.
Part 1: A Personal Investigation
Part 2: Generations of Loss
Part 3: How Dioxin Damages Generation After Generation
Part 4: What Remains
Most epidemiological studies about the effects on children of dioxin, the highly toxic substance found in Agent Orange, have tended to focus on women, since the link between cause and effect can be much clearer with women’s exposure to dioxin. If a pregnant woman is exposed to a toxic substance in what she breathes, touches, and consumes, the DNA of the developing embryo can be altered, causing birth defects and health anomalies at birth and afterward.
For example, a longitudinal study looked at blood samples from two cohorts of women and their children born exposed to high levels of dioxin similar to that used in Agent Orange, following a 1976 explosion at a dioxin manufacturing plant in Seveso, Italy, near Milan. The accident spread a highly concentrated cloud of dioxin that contaminated land and crops over an 18 square kilometer area, similar to the level of contamination from Chernobyl. Victims and their children suffered from cardiovascular, lung, and digestive disorders. Company executives found responsible were jailed. Large-scale dioxin releases in Missouri, Taiwan, Japan, and Canada have found patterns of childhood mutations.
The US Department of Veterans Affairs provides compensation and medical care for severe birth defects among the children of the approximately 7,500 American women veterans who served in Vietnam. According to the VA, 1,325 children have met the criteria and have received what are reported to be low levels of benefits through 2016. That equates to an 18% incidence level of birth defects among women veterans — three times the current rate for the non-veteran population.
Laura Nichols, 50, of Pilot Mountain, North Carolina, is one of this rare group of children of women Vietnam veterans who have received compensation from the VA, for hip dysplasia, a congenital condition in which the hip socket does not cover the ball of the hip and that leads to recurring and painful dislocations. She has also experienced bouts with cervical cancer, thyroid cancer, and melanoma. In June 2020, she was declared 100% disabled by a VA judge and will now receive $2,000 per month, although she continues to struggle with the VA to get care through the limited health insurance it provides. Her eldest son was diagnosed with bladder cancer at age 14, and has had 11 surgeries in five years. Another son had a birth defect in his foot.
Nichols’ mother, Marylyn Gardner, was a first lieutenant in the US Army Nurse Corps. She was the head nurse of a 900-bed hospital in Cam Rahn Bay, Vietnam, from 1967 to 1969, and took part in 14 classified helicopter missions. Nichols’ mother once showed her a photo of cut-in-half Agent Orange barrels that the nurses would shower in every day using collected rainwater, a common story among the children of veterans I’ve interviewed. Her mother passed away from lung cancer in 2011, four months after she was diagnosed and less than a year after she had retired from a career as a nurse and a nursing home administrator.
The government has accepted responsibility for the birth defects of some of the disabled children of women veterans exposed to Agent Orange. But the only birth defect so far recognized for the children of male American veterans is spina bifida in which the spinal cord does not close properly. Could there be other conditions that would one day be recognized?
After all, studies of male Vietnam veterans from Australia and New Zealand have found consistent patterns of central nervous system, skeletal, and cardiovascular damage in veterans’ children from dioxin exposure. The Australian Department of Veterans Affairs provides treatment to children of Vietnam veterans with spina bifida, cleft lip or palate, acute myeloid leukemia, and adrenal gland cancer, for example.
Once I heard about the serious health problems in many children whose fathers had served, I wondered how it might be possible for men to pass along defects to their children from exposure to Agent Orange.
A staggering amount of time and money has been spent over the last 50 years on cataloging and analyzing the health effects of Agent Orange in US veterans. One of the longest-running efforts is a report exhaustively detailing the current state of research on Agent Orange published every two to three years since 1994 by the National Academies of Sciences, Engineering, and Medicine (NASEM). In the NASEM’s 2018 edition of its Agent Orange study, the committee determined that there was “inadequate or insufficient evidence” to determine whether an association existed between exposure to the dioxin in Agent Orange and pregnancy and fertility problems, miscarriages, stillbirths, birth defects, childhood cancers, and other health issues in the children of veterans. NASEM has issued similar findings in previous editions.
The NASEM’s statement does not mean that there is no association, experts say, only that it has determined that no definitive study showing an association exists.
Reading the hundreds of pages of assembled scientific evidence is like being washed over with convincing data points that nonetheless have been collectively deemed “insufficient” owing to one methodological technicality or another. But a single sentence galvanized my attention: “The potential does exist, however, for TCDD [dioxin] to alter the sperm cells of adults before fertilization through epigenetic pathways,” the report stated suggestively.
What did this mean? To find out, I went even deeper down a scientific rabbit hole.
The Diseases We Inherit
It was long thought that damage to an embryo caused by environmental exposure in men could result only from changes in the DNA of sperm. That was the main route imagined for the transmission of genetic mutations, since men contribute their DNA to an egg through their sperm.
But scientists are starting to understand that men can also pass down birth defects through what is known as transgenerational epigenetic inheritance (TEI). Dioxin and many other environmental toxins can modify a cell’s genetic material without altering DNA, through the regulation of what’s known as the epigenome.
These changes attach to, or ride on top of, the genome (“epi” means “above” in Greek) and control whether genes turn on or off. Errors in this epigenetic process can cause genetic disorders and ultimately diseases such as cancer, metabolic disorders, and degenerative diseases that can be passed down to offspring, generation after generation. In other words, we are more than the sum of our DNA. What we are exposed to in our environment can influence not only our genes but also the genes of our descendants.
Linda Birnbaum is a leading US toxicologist and Agent Orange expert who has studied the effects of dioxin and other environmental contaminants for decades. She told me that epigenetics is a “likely mechanism” for male-mediated transmission of birth defects in veterans. Birnbaum spent the last ten years of her 40-year government career as the director of the National Institute of Environmental Health Sciences (NIEHS), a $775 million agency that’s part of the National Institutes of Health (NIH). She retired from government in 2018 after disagreeing with the actions by the Trump-administration EPA and others, and is now free to speak her mind.
“I think the military wants to avoid any liability,” she says. “They’ll do anything they can to do that.”
For a long time, there was really no clear human data showing paternal effects from dioxin exposure, says Birnbaum. But a large number of recent studies have shown a clear link between dioxin exposure and mutations in animals. For instance, a 2012 study in PLOS One by Mohan Manikkan and colleagues found that dioxin exposure in pregnant female rats caused a multitude of adult-onset diseases in the rat’s grandchildren.
Birnbaum says only one long-term study exists of paternal transmission of genetic defects following dioxin exposure. The US Air Force conducted it on the men who flew the planes that sprayed Agent Orange. They flew “low and slow” like crop-dusters over the treetops, straight into enemy fire, taking the most enemy hits of any aircraft in the Air Force. These “Ranch Handers” were highly exposed to dioxin as they physically handled barrels of Agent Orange and as the clouds of toxic herbicides drifted back into their planes while they were spraying over the jungles of Vietnam.
In its longitudinal study of the 2,613 Ranch Handers from 1982 to 2002, the Air Force failed to find a connection between Agent Orange exposure and any health problems in veterans, as well as between Agent Orange and any birth defects and health problems in veterans’ children. It did find an elevated rate of birth defects.
A scientist involved in the Air Force’s Ranch Hand Study has charged that his superiors altered results and methodology to cause the findings to appear less statistically conclusive. In testimony before Congress in 2000, Dr. Richard Albanese, a lead investigator of the Air Force study, found that after controlling for the data that the Air Force had excluded, he found 50 percent more birth defects in the children of the sprayers of Agent Orange than in the control group of non-Ranch Hand veterans. A 1994 report had faulted the Ranch Hand Study for numerous methodological lapses, including the exclusion of critical data, criticism that continued to dog the report’s methodology.
To address methodological concerns such as these, the Air Force released the full data set of the Ranch Hand Study to the Vietnam Veterans Association in 2000 for independent analysis. In 2018, an analysis of the data, which has so far gone unreported, was published in the peer-reviewed Open Journal of Epidemiology by George Knafl, an emeritus professor at the University of North Carolina School of Nursing. Knafl reran the Air Force numbers, including the veterans that the Air Force had excluded in its methodology. After including veterans that the Air Force had excluded, the children of Ranch Handers with high dioxin levels were nearly twice as likely to have a major birth defect as the children of both non-Ranch Hand participants and Ranch Hand participants having lower dioxin levels.
The upshot: Having a high dioxin level was significantly related to having children with major birth defects.
Linda Schwartz, a highly decorated Air Force nurse who treated wounded soldiers evacuated from Vietnam to Japan and became an expert about women veterans exposed to Agent Orange, worked together with Knafl on an earlier unpublished version of his study. She confirmed the significance of his recent findings. As former assistant secretary of veterans affairs for policy and planning under President Obama and chair of the steering committee of the VA’s Vietnam-Era Veterans Mortality Study, the retired Air Force major and loyal “blue-suiter” has testified more than two dozen times before Congress.
“I have a long and storied history of fighting the Air Force Ranch Hand Study,” she told me. “I don’t think the study did justice to the Air Force.”
Next Up, Part 4 in the Series: What Remains
