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Back to the Future:
EPA Reinvents the Wheel
on Reproductive Effects of Dioxin
by Carol Van Strum
In September, 1994, the US Environmental Protection Agency released its draft "reassessment" of dioxin hazards. The reassessment was initiated at the insistence of the chlorine industry five years ago. One of its inescapable conclusions is that, contrary to the industry hype surrounding the reassessment, dioxin is in fact worse than EPA suspected. In particular, EPA researchers now find that dioxin is even more potent a cause of reproductive and immune system effects than it is of cancer.
EPA's findings are hardly news to those familiar with the sordid history of dioxin research and regulation. Indeed, the current report merely confirms and reasserts conclusions reached decades ago, when the military banned Agent Orange and EPA initiated its first efforts to regulate domestic use of dioxin-laced herbicides. By 1979, evidence of dioxin's extraordinary reproductive toxicity was strong enough to warrant emergency action by EPA on the basis of imminent hazard to humans. How that very evidence was subverted, covered up, denied, and ignored for fifteen years while dioxin sources proliferated is an important context for EPA's current research, lest history repeat itself yet again.
During the mid-1960s, as US defoliation campaigns in Vietnam were escalating, a government study conducted by Bionetics Laboratories revealed that dioxin-contaminated components of Agent Orange and other military defoliants caused severe birth defects in the offspring of exposed animals. The Bionetics report came to light in 1969, compounding reports of birth defects and other reproductive damage in Vietnamese populations exposed to Agent Orange. Public and scientific outrage, coupled with Congressional hearings on the subject, forced the military to ban use of Agent Orange in Vietnam in 1970.
That same year, President Nixon created the Environmental Protection Agency in what Nixon described as a "delaying action" to protect business from environmentalists. Despite the military ban on Agent Orange, and despite an urgent warning by the US Surgeon General that dioxin-laced herbicides "may present an imminent hazard to women of child-bearing age," domestic uses of Agent Orange chemicals continued and expanded over the next decade. From its very beginning, the fledgling EPA yielded to manufacturers' repeated calls for further study of whether dioxin could be found in the environment and what levels constituted a hazard.
Cooperating with industry in such studies, EPA's own laboratories by 1975 reported frightening levels of dioxin in tissues of animals and birds from sprayed roadsides, in beef cattle grazed on sprayed range land, and in human mothers' milk from sprayed areas of Oregon, Texas and Vietnam. EPA took no action, however, until a group of rural Oregon residents, disturbed by birth defects, miscarriages, and illnesses in their families, livestock, and local wildlife following aerial defoliation missions by the US Forest Service, filed a lawsuit that forced EPA's suppressed dioxin studies into the open; on the basis of these studies and the government's failure to determine the safety of chemicals before using them, the Oregon Citizens Against Toxic Sprays (CATS) in 1977 won a landmark federal court decision banning the use of dioxin-contaminated herbicides on national forest lands.
...a "no safe level" dioxin policy would literally halt manufacture of plastics, pulp and paper, wood preservatives, gasoline, solvents, pharmaceuticals, etc., and would create liability for the government against the claims of Vietnam veterans exposed to Agent Orange.
Following the court order in the CATS case, EPA began a study of human miscarriages in the sprayed forest area of Oregon involved in the CATS case. This study, known as the Alsea study after a small town within the 1600 square mile study area, became the heart of EPA's regulatory effort on dioxin—and earned the dubious honor of becoming the most influential unpublished, unfinished study in EPA history.
The Alsea Study was an attempt to correlate human miscarriages with the time, amount, and location of aerial herbicide applications, as well as with actual dioxin levels in the locations where the miscarriages occurred. In early 1979, a preliminary report on the statistical correlation of miscarriages with spraying showed an overwhelming surge of miscarriages during the two months following herbicide applications. On the basis of this preliminary report, EPA issued an emergency suspension of forestry and rights-of-way uses of 2,4,5-T and silvex, without waiting for the results of dioxin sampling in the study area.
Based on the preliminary Alsea Study statistics and a Dow study showing effects of dioxin exposure over three generations of rats, the EPA Administrator took the strong position in suspending 2,4,5-T that no safe or no-effect level of dioxin exposure could be demonstrated, and that its reproductive toxicity presented an imminent hazard to exposed populations at any level:In my judgment, the information which has recently come to my attention as a result of the Alsea study constitutes a dramatic and troubling new point of departure for analysis of TCDD exposure concerns. As indicated above, these data show a striking relationship between 2,4,5-T use and increased incidences of spontaneous abortions among women residing in the use area. As further developed above, this effect is an effect which one would have predicted as a likely outcome of human exposure, based upon a body of animal data of almost unprecedented conclusiveness. The Alsea study, to be sure contained no data showing actual exposure. However, concern for the health of humans who may be exposed to 2,4,5-T and its contaminant, TCDD, is heightened because scientists have not demonstrated that there is a level of exposure that has no adverse effects in humans. *
EPA's strong "no safe level" dioxin policy and its emphasis on reproductive toxicity immediately created a mare's nest of conflicts for the agency, which at that time was promoting waste-to-energy garbage incinerators that spewed out far greater amounts of dioxin than was found in 2,4,5-T. In addition, significant other industrial sources of dioxin were being discovered; a "no safe level" dioxin policy would literally halt manufacture of plastics, pulp and paper, wood preservatives, gasoline, solvents, pharmaceuticals, etc., and would create liability for the government against the claims of Vietnam veterans exposed to Agent Orange.
Faced with such conflicts, EPA concealed from the public and from its own scientists the remainder of the Alsea Study, the exposure data showing dioxin residues in wildlife, deer and elk meat, human milk, drinking water sediments, and human tissue from a baby born without a brain. EPA not only concealed these results from its own scientists and lied about them to the sample donors, the agency further prevented the scientists conducting the Alsea Study from publishing their results or defending their conclusions at scientific or other public meetings. The only "published" version of the Alsea Study that exists to this day is a flawed and misleading "critique" of the preliminary data in EPA's suspension notice, published by Oregon State University. EPA never publicly defended its Alsea Study against the industry attack, and refused to fund or participate in a Centers for Disease Control study of the Alsea area after a preliminary CDC study found a 13-fold increase in neural tube birth defects in children born to women living in the area.
While keeping the "smoking gun" dioxin analyses from the Alsea Study covered up, EPA began closed door settlement negotiations with Dow in the opening months of the Reagan Administration. By 1983, a draft settlement had been drawn up that would allow 2,4,5-T back on the market with "allowable" levels of dioxin. This settlement was scuttled not by science or common decency, but by scandal. The "leak" of the Alsea dioxin analyses, compounded by EPA's preposterous claim that the leaked data had been "mixed up" with data from Dow's Midland plant, prompted Dow and EPA separately, on October 14, 1983, to announce final cancellation of all 2,4,5-T registrations. EPA's emergency ruling that dioxin posed an "imminent hazard" of reproductive harm at any dose level, along with the voluminous evidence supporting it, were thus relegated to EPA archives and conveniently forgotten.
The demise of 2,4,5-T allowed EPA—quietly and without public notice or comment—to replace its "no safe level" of dioxin policy with an exciting new technique in the field of numerology called "risk assessment." In theory, risk assessment correlated the toxicity of a substance with the amount of exposure in order to predict the casualty rate. In practice, EPA risk assessment reached a predetermined acceptable body count by substituting assumptions for actual data and cloaking the resultant nonsense in unintelligible algebraic formulas. Such legerdemain allowed regulators first to determine that a certain number of deaths was "negligible" and therefore acceptable, and second, to juggle toxicity and exposure data to fit into an "acceptable" model.
Discarding the human data on dioxin's reproductive toxicity developed in the 2,4,5-T proceedings, EPA numerologists assumed that its carcinogenic potency outweighed all other effects. Although dioxin was well-established to be an exquisitely potent carcinogen in laboratory animals, the elusive nature of human cancer suited the risk assessor's purpose admirably: because it takes decades to manifest itself in humans, pinpointing a causative agent is confounded by years of other exposures, lost records, the likelihood of subjects dying of other effects before cancer can develop, and, for dioxin, the fact that the few human studies available omitted women entirely. This dearth of human data enabled risk assessors further to assume that dioxin was a far less potent carcinogen in humans than in all other animal species.
EPA developed increasingly arcane risk assessments to justify continued dioxin pollution even as the evidence linking dioxin to cancer became overwhelming.
For fifteen years after its 1979 emergency "no safe level" action, as known sources of dioxin expanded to include uses of chlorine throughout commerce, EPA developed increasingly arcane risk assessments to justify continued dioxin pollution even as the evidence linking dioxin to cancer became overwhelming. Under pressure from the entire chlorine industry and its vast array of industrial customers, EPA, together with industry, spent billions of dollars on research to establish a safe level of dioxin exposure. The result, embodied in the current risk assessment, is a costly reinvention of the wheel, confirming what EPA knew in 1970 and took emergency action on in 1979: that dioxin is not only a potent carcinogen, but also that its reproductive toxicity exceeds its carcinogenic potency and that no safe or "no effect" level can be established.
Drafts of EPA's new risk assessment indicate that to evade the inescapable evidence of dioxin hazard, EPA will manipulate the exposure factor in its risk assessment formulas to minimize the resulting risk and allow dioxin pollution to continue. This will be accomplished by substituting computer models for actual exposure data, i.e., substituting "virtual reality" for real-world information. Instead of tracking chlorine and its inevitable dioxin spoor throughout the economy, EPA will "model"—i.e., guess—exposure from each source in isolation, without any means of calculating total cumulative exposure from all sources, past and present.
In summary, the reproductive effects of dioxin were known thirty years ago, were the basis for the 1970 ban of Agent Orange by the military in Vietnam, were the basis for EPA's 1979 emergency suspension of 2,4,5-T, and were deliberately suppressed and subverted in the elusive quest for carcinogenic evidence that would take decades to develop and would never be anything but equivocal. EPA has never taken emergency action on the basis of cancer. Now that science has rediscovered the wheel on reproductive effects of dioxin, the precedent of the 1979 emergency suspension based on precisely those effects-and finding any level of dioxin to present an "imminent hazard"—should prompt immediate, emergency action on all dioxin sources.
* US EPA. Decision & Emergency Order Suspending Registrations for the Forest, Rights-of-Way, and Pasture uses of 2,4,5-Trichlorophenoxyacetic Acid (2,4,5-T). 44 Fed. Reg. 15874 (March 15, 1979).
For a referenced version of this article, write S/R or contact the author at 7493 East Five Rivers Road, Tidewater OR 97390. Also see Carol Van Strum & Paul Merrell (1987), No Margin of Safety: A Preliminary Report on Dioxin Pollution and the Need for Emergency Action in the Pulp and Paper Industry. From Greenpeace, 1436 U Street NW, Washington DC 20009.