(Beyond Pesticides, August 8, 2024) With the use of its emergency authority—not used in nearly 40 years, the U.S. Environmental Protection Agency (EPA) on August 7 banned a pesticide (the weed killer Dacthal or DCPA—dimethyl tetrachloroterephthalate) under the “imminent hazard” clause of the federal pesticide law. At the same time, the agency is exercising its authority to prohibit the continued use of Dacthal’s existing stocks, a provision that EPA rarely uses. EPA identified serious concerns about fetal hormone disruption and resulting “low birth weight and irreversible and life-long impacts to children [impaired brain development, decreased IQ, and impaired motor skills] exposed in-utero” and finds that there are no “practicable mitigation measures” to protect against these hazards. The last time EPA issued an emergency action like this was in 1979 when the agency acknowledged miscarriages associated with the forestry use of the herbicide 2,4,5-T—one-half of the chemical weed killer Agent Orange, sprayed over people to defoliate the landscape of Vietnam in the war there—with the most potent form of dioxin, TCDD (2,3,7,8-Tetrachlorodibenzo-p-dioxin). While EPA has been congratulated for using its emergency authority, which it is obviously reluctant to use, and health and environmental activists say could be used broadly, the timeline […]

(Beyond Pesticides, August 2, 2024) In a recent study published in Science, a team from the University of Massachusetts and Yale University provides quantitative insight into the significant effects of a recent U.S. Supreme Court decision on the nation’s water quality. This research highlights the essential role of ephemeral streams—water sources that flow temporarily after rainfall—in transporting pollutants, including pesticides, sediments, and nutrients from land to larger water bodies.  This comprehensive study underscores the devastating risk to U.S. water quality, stemming from the May 2023 U.S. Supreme Court decision, Sackett v. Environmental Protection Agency (EPA), which dramatically limits the agency’s ability to protect ephemeral streams as well as critical wetland ecosystems under the Clean Water Act (CWA).  As a May 2024 report by Clean Water for All Coalition notes, “The [Sackett] decision has endangered the drinking water sources of at least 117 million Americans by stripping protections from over half of the nation’s wetlands, as well as up to nearly 5 million miles of rain-dependent and seasonal streams that feed into rivers, lakes, and estuaries.” At a time when an immediate response to the climate crisis and chemical pollution is more urgent than ever, the U.S. Supreme Court’s judicial decisions are seen […]

(Beyond Pesticides, July 24, 2024) The Center for Food Safety—joined by environmental, farm, and grassroots organizations including Beyond Pesticides—submitted a groundbreaking petition yesterday to the U.S. Environmental Protection Agency (EPA), urging immediate action to address the presence of per- and polyfluoroalkyl substances (PFAS) in pesticides and pesticide containers. Numerous studies have shown that the broad use of PFAS chemicals, and the resulting environmental contamination, has devastating impacts on public health, wildlife, and pollinators. Despite acknowledging PFAS as an urgent public health and environmental issue, EPA has upheld hundreds of registrations of pesticide ingredients that fall into the PFAS category. Furthermore, EPA has allowed the ongoing use of fluorinated pesticide storage containers, despite the agency itself finding that these containers leach PFAS chemicals into pesticide products.   PFAS, known as “forever chemicals” due to their ability to persist in the environment, are endocrine disruptors, which are linked to developmental issues, cancers, and organ damage. Crops can uptake PFAS from soil, resulting in dietary exposure for both the public and wildlife, while PFAS ingredients in pesticides can also leach into groundwater, contributing to widespread PFAS drinking water contamination. In recent years, EPA has acknowledged this critical issue and committed to addressing PFAS contamination outside […]

(Beyond Pesticides, July 16, 2024) Yet another study in the August 2024 journal Ecotoxicology and Environmental Safety has found that exposure to organophosphorus pesticides (OPPs) is correlated with increased suicidal thoughts in some people. This study is just the latest in a long line of studies from around the world that have linked pesticide exposure to mental health conditions, including sleep disorders, depression, and suicidal ideation (SI). As the rate of suicide increased by 30% between 2000 and 2020, there is an urgent public health need to investigate and address all potential contributing factors. A 2019 study, covered in Daily News, found that teens and adolescents living in agricultural areas and exposed to organophosphate (OP) insecticides are at higher risk of depression, In July and January this year, other studies link farmer psychiatric episodes to pesticide exposure, adding to the body of science. Exposure to household pesticides is also linked to depression in a 2020 study.   Study and Methodology  The study entitled “Association between exposure to organophosphorus pesticide and suicidal ideation among U.S. adults: A population-based study,” analyzes information on the mental and physical health of over 5,000 individuals aged 20 and up in the United States. The study aims […]

(Beyond Pesticides, July 15, 2024) It is hot. Really hot. A serious response to this climate emergency requires, according to environmental advocates, a dramatic transformation in land management and an end to the use of petrochemical pesticides and fertilizers. Beyond the real-world adverse effects of the climate crisis— more intense and frequent fires, floods, hurricanes and hail storms, as well as the harm to health and biodiversity—the rising insurance premiums imposed by the insurance industry speaks to the need for an urgent systemic response. According to the paper, Pricing of Climate Risk Insurance: Regulation and Cross-Subsidies, “The unprecedented rise in natural disasters has led to catastrophic losses of more than $600 billion in the United States over the last two decades, roughly twice the losses of the previous 40 years combined.” While the events associated with climate are more accurately described as “human-made” rather than “natural” disasters, a 2023 Washington Post article reports that, “U.S. insurers have paid out $295.8 billion in natural disaster losses from 2020 to 2022, a record for a three-year period.” This has led to dramatic changes in the cost of insurance coverage and the decision of many carriers to deny coverage. The Washington Post writes, “At least […]

(Beyond Pesticides, July 9, 2024) Last month, California cannabis regulators recalled a pesticide-tainted vape, one of the contaminated products identified in a Los Angeles Times investigation. The report reveals that the California Department of Cannabis Control (DCC) has for months been aware of the presence of dangerous chemicals in legal cannabis sold to the public. Conducted by Los Angeles Times and WeedWeek, a cannabis industry newsletter, the investigation has uncovered alarming levels of the insecticide chlorfenapyr in legal cannabis products sold in state dispensaries. According to an article via the National Institutes of Health, “Although [chlorfenapyr] has been identified as a moderately toxic pesticide by the World Health Organization (WHO), the mortality rate of poisoned patients is extremely high. There is no specific antidote for chlorfenapyr poisoning.” The chemical is associated with adverse liver effects and is toxic to bees, birds, and aquatic organisms. Despite claims that the state’s cannabis is safe and regulated, many popular brands of vapes and pre-rolled joints were found to contain dangerous pesticides at levels exceeding state limits and federal standards for tobacco. This investigation comes on the heels of the discovery of large amounts of illegal Chinese pesticides at cannabis grow operations around the state. […]

(Beyond Pesticides, July 4, 2024) In reflecting on recent U.S. Supreme Court decisions that reduce federal government powers to restrict hazardous chemicals, including pesticides (see Clean Water Act decision and federal restrictions of toxic hazards under the reversal of Chevron decision), two remaining authorities in state and local governments and in the courts have become the next battleground to protect health and the environment. What is at stake are two major backstops to weak federal controls and chemical company disregard for safety: the critical importance of state and local governments’ exercise of authority to restrict toxic chemicals, and the ability of people to sue corporations for their failure to warn about their products’ hazards.  The attack on state and local authority in the Farm Bill The Farm Bill in the U.S. House of Representatives: Prohibits the rights of states and local governments to restrict pesticides and protect public health and the environment. The language says the Farm Bill will “prohibit any State, instrumentality or political subdivision thereof… from directly or indirectly imposing or continuing in effect any requirements for, or penalize or hold liable any entity for failing to comply with requirements with respect to, labeling or packaging that is in […]

(Beyond Pesticides, June 14, 2024) The influence of the chemical industry over public policy and regulation, especially in agriculture, is glaringly obvious and has little popular support, yet no one can seem to do anything about it. Numerous analyses have detailed the ways this influence is applied—through lobbying and political donations including dark money; industry experts named to regulatory agency scientific advisory boards; and the massive public relations machines that create and sustain public uncertainty using the tobacco industry playbook revealed by Naomi Oreskes and Erik Conway in their 2010 book Merchants of Doubt. A more insidious tendril of industry influence is explained in U.S. Right to Know’s (USRTK) report, released this month, on pesticide manufacturers’ infiltration of the Entomological Society of America (ESA). The report, “Anatomy of a science meeting: How controversial pesticide research all but vanished from a major conference,” examines the ESA’s 2023 annual meeting—its program, sponsorships, presentations, panelists, poster sessions, meet-and-greets, budget, revenue sources, and other aspects of the event. What is revealed is a systematic and comprehensive industry presence throughout the society and its meeting. A direct consequence is the near-elimination of any scientific presentations addressing the effects of neonicotinoid pesticides on insects, particularly bees. […]

(Beyond Pesticides, June 13, 2024) A study published in Conservation Letters, a journal of the Society for Conservation Biology, exposes critical shortcomings in the U.S. Environmental Protection Agency’s (EPA) ecological risk assessment (ERA) process for modeling the risks that pesticides pose to bees and other pollinators. For the study, “Risk assessments underestimate threat of pesticides to wild bees,” researchers conducted a meta-analysis of toxicity data in EPA’s ECOTOX knowledgebase (ECOTOX), an EPA-hosted, publicly available resource with information on adverse effects of single chemical stressors to certain aquatic and terrestrial species. The meta-analysis found that the agency’s approach, which relies heavily on honey bee data from controlled laboratory studies, drastically underestimates the real-world threats from neonicotinoid insecticides (and likely other pesticides) to native bees and other pollinators. The study “challenges the reliability of surrogate species as predictors when extrapolating pesticide toxicity data to wild pollinators and recommends solutions to address the (a)biotic interactions occurring in nature that make such extrapolations unreliable in the ERA process.” Beyond Pesticides executive director Jay Feldman remarked, “EPA’s ecological risk assessment process is fundamentally flawed and puts thousands of bee species at risk of pesticide-caused population declines and extinctions.” Mr. Feldman continued, “This underscores the urgent […]

(Beyond Pesticides, June 4, 2024) A study published in the most recent edition of the journal Ecotoxicology and Environmental Safety documents for the first time the presence of the herbicide glyphosate in human sperm. The study looked at 128 French men with an average age of 36 years who tested positive for glyphosate in their blood. Seventy-three out of the 128 men were found to also have glyphosate in their seminal plasma. Not only that, the amount of glyphosate in seminal plasma was nearly four times higher than what was detected in the blood.   Methods  The study involved a population of 128 infertile French men from whom seminal and blood plasma samples were collected. The study was conducted at the “Pole Santé Léonard de Vinci” medical center, located centrally near Tours, France. This region is recognized for its urban characteristics as well as being a major agricultural hub, particularly for grain and wine production. The study authors note, “This area reflects the common herbicide exposure in France” and the district ranks third highest in terms of pesticide purchases. While additional qualitative data was collected, only 47 of 128 participants fully completed a questionnaire about their profession, diet (organic or […]

(Beyond Pesticides, May 23, 2024)  A study recently published in the journal Nature compared the impact of organic and conventional food production using eight environmental health indicators and found that organic food has a significantly lower environmental impact than conventional food production for six of the eight indicators, including a lower potential for contributing to acidification of the environment, energy use, and biodiversity loss. For the analysis, scientists reviewed 100 different “life cycle assessments” (LCA) of organic and conventionally grown food products from cradle-to-farm gate.    LCA is a commonly used methodology to estimate food production system impacts on the environment through resource depletion and pollutant emissions. The results—that organic food production is less impactful on the environment—add to the robust body of research that underscores the importance of organic farming to the development of a sustainable global food system while addressing climate change. Beyond Pesticides has long argued that one of the most powerful tools in fighting global warming is organic agriculture, as it sequesters atmospheric carbon, eliminates the use of fossil fuel-based synthetic fertilizers and synthetic pesticides, and provides environmental and human health benefits. This study and most of the 100 studies it evaluates, do not recognize that conventional […]

(Beyond Pesticides, May 20, 2024)  (Beyond Pesticides, May 20, 2024) The Republican Farm Bill draft in the U.S. House of Representatives, released on Friday, May 17, is a broad attack on pesticide restrictions and the right to sue chemical manufacturers and allied users of pesticides when harmed. “This legislation is a complete nonstarter for the millions of people who want stronger pesticide restrictions, democratic decision making on toxic chemicals in communities, and the right to sue manufacturers and pesticide users when harmed and misled on the hazards of pesticides,” said Jay Feldman, executive director. “We vehemently oppose this Republican legislation with the understanding and experience—bridging farmers, medical practitioners, land managers, local policy makers, and families—that we can and must transition to safe practices and products that protect our health, biodiversity, and climate,” Mr. Feldman continued. The Farm Bill attack takes place on many critical fronts. The draft legislation: 1. Takes away the right to sue for failure to warn when harmed by pesticides. The language says: “prohibit. . .a court from directly or indirectly imposing or continuing in effect any requirements for, or penalize or hold liable any entity for failing to comply with requirements with respect to, labeling or […]

(Beyond Pesticides, May 15, 2024) A study published recently in the journal Environmental Research finds a significant correlation between exposure to certain pesticides and an elevated risk of inflammatory bowel disease (IBD), a chronic autoimmune condition of the gastrointestinal tract. The study, adding to the body of science on this subject, evaluates self-reported data from licensed pesticide applicators and their spouses exposed to pesticides for over 20 years. In addition, while some of the chemicals found to be most closely associated with incidents of IBD have been banned from use, they are “forever” chemicals that persist in the environment for generations. These findings demonstrate once again the failings of the current regulatory process to identify hazards before they are put into the environment. The study found evidence that exposure to several organochlorine insecticides (dieldrin, DDT, and toxaphene), as well as organophosphate insecticides (parathion, terbufos, and phorate) and herbicides (2,4,5-T, 2,4,5-TP, and metolachlor), is associated with elevated IBD risk. IBD is a generic term for diseases that result in chronic inflammation of the gastrointestinal tract, such as Crohn’s disease and ulcerative colitis. It is estimated that 6.8 million patients globally suffered from IBD in 2017. IBD may result from an imbalance […]

(Beyond Pesticides, May 10, 2024) A study published by scientists in France from La Rochelle University’s Chizé Center for Biological Studies, in collaboration with the University of Strasbourg and the University of Burgundy, finds lower pesticide load in chicks from a bird of prey species in areas with organic farming. A correlation between lower numbers of pesticides in the blood of birds with the presence of organic farms surrounding the habitats was determined after analyzing 55 Montagu’s harrier (Circus pygargus) nestlings from 22 different nests in southwestern France. As the percentage of organic agriculture around the nests increased, there was a significant decrease in the quantity and types of pesticides detected within the chicks’ blood.  In beginning this study, the scientists hypothesized that “the application of organic farming practices is expected to reduce contamination levels in the environment and consequently in wildlife.” They also referenced studies, such as a soil study, that aided in this speculation: “In an analysis of topsoil samples collected across Europe, samples from organic farms showed significantly fewer pesticide residues and in lower concentrations than those from conventional farms … [with] 70 to 90% lower concentrations.”   This study screened for 104 total compounds, 28 of which […]

(Beyond Pesticides, May 8, 2024) In an unexpected turnaround, the U.S. Environmental Protection Agency (EPA) announced at the end of April a Proposed Interim Decision (PID) to discontinue all but one application of the insecticide acephate. Acephate is an organophosphate pesticide, a well-known neurotoxicant, widely banned globally, including in the European Union. Under the proposal, all uses would end except for the injection of trees that do not produce fruit or nuts. In its proposed action, EPA asks the manufacturer to offer the agency a voluntary settlement, a process that typically compromises the health of the public, workers, and the environment. Acephate, an organophosphate (OP) pesticide, is approved for use in both agricultural settings, including crops like cotton and soybeans, and nonagricultural applications, such as injections for forestry trees. Acephate affects the nervous system by inhibiting the acetylcholinesterase (AChE) enzyme. Importantly, chronic, low levels of exposure can cause a range of adverse human health outcomes, from cancer to birth defects, reproductive and developmental problems, and learning disabilities. While the proposed April interim decision, if it comes to pass, is welcomed by advocates, some are concerned that EPA’s proposal does not fully critique the scientific documents and conclusions on risk that […]

(Beyond Pesticides, May 7, 2024) The marginal user costs (MUC) of pesticide resistance for chemical-intensive farmers and the pest management industry are significantly affected by pesticide costs, density dependence (growth rate of a pest population impacted by its density), and dominant genetic mutations that cause resistance, according to a novel study published in Journal of the Agricultural and Applied Economics Association. Although the authors believe that integrated pest management (IPM) can be fine-tuned based on these findings, many advocates believe that these findings in fact underscore the importance of eliminating toxic pesticide use amidst compounding climate, biodiversity, and public health crises—which many IPM strategies do not adequately address. As the costs of petrochemical-based pesticides increase, organisms identified as pests continue to increase in population density as global and regional temperatures dually increase. Organic agriculture, and organic land management principles more broadly, are an economically and ecologically advantageous leap ahead in transitioning to a food system that moves beyond the status quo that poisons people and the planet. “This paper seeks to develop a better understanding of how the user costs of resistance are potentially determined by the interactions of heterogeneous bioeconomic factors that vary by context,” say the study authors. […]

(Beyond Pesticides, May 6, 2024) The pattern of failure to protect the public from pesticides is again brought to public attention by an analysis by Consumer Reports (CR) that effectively updates its previous report released in 2020. The report and its earlier iteration identify deep structural weaknesses with the institutions charged with protecting the public’s health and safety. The health risks outlined by CR in 2020 and related to ongoing pesticide exposure, even at low levels, include cardiovascular diseases, cancers, reproductive dysfunction, respiratory problems (e.g., asthma, bronchitis), neurological impacts (e.g., developmental effects and dementia/Alzheimer’s), and endocrine dysfunction, among others. Previously, the magazine reported, “CR’s experts say the government hasn’t upheld its responsibility to protect consumers [and that] the research used to set [pesticide residue] tolerances is imperfect, and they’re often too high.” CR has cited the U.S. Environmental Protection Agency (EPA), which is primarily responsible for pesticide regulation, for multiple inadequacies. According to the latest CR analysis, the U.S. Department of Agriculture (USDA) Pesticide Data Program (PDP) Annual Summary has once again failed to accurately portray the safety of some of the most commonly sold fruits and vegetables in the United States. CR reviewed seven years of PDP data, finding that 20% […]

(Beyond Pesticides, May 3, 2024) Parkinson’s disease (PD) is the second most common neurodegenerative disease in the world after Alzheimer’s. Genetic factors account for only a fraction of PD cases, and for decades scientists have been aware of associations between pesticide exposures and PD. Yet, not everyone exposed to pesticides gets PD. Consequently, neither the genetic nor the environmental hypothesis is fully satisfactory; both may be involved. Thus, there has been great interest in identifying gene variants that affect the risks of PD associated with pesticide exposure. Now a team of University of California at Los Angeles researchers led by neurologist Brent Fogel, MD, PhD has traced a connection between certain gene variants and the occurrence and severity of PD in a cohort of central California PD patients who have had long-term exposure to pesticides. The genes are related to autophagy, the process by which cells organize, degrade, recycle or eject molecules to maintain healthy chemical balance. Autophagy is an essential process throughout the body, including regulation of mitochondria, which are also vital for healthy cellular function. The study supports other research suggesting that autophagy is disturbed in neurodegenerative diseases. As Beyond Pesticides discussed in its April 19 Daily News, PD […]

(Beyond Pesticides, April 26, 2024) Researchers build on existing research when assessing the relationship between long-term exposure to organophosphorus pesticides—widely used in food production and homes and gardens—and the human gut microbiome. In a new study published in Environmental Health, an interdisciplinary research team from University of California, Los Angeles determined, “that exposure to [organophosphorus pesticides] is associated with changes in the abundance of several bacterial groups and differential functional capacity in metabolic pathways supported by the human gut microbiome.” The study draws upon data from a “Parkinson’s, Environment and Gene study (PEG)” in which 190 participants were asked to submit fecal samples and answer interview questions. “[The study] was initially designed to investigate the etiology of Parkinson’s disease (PD) and participants were recruited in two study waves [‘over the full 10-year exposure window’]: 2001–2007 and 2012–2017. At baseline, [Parkinson’s disease] patients were diagnosed within the past 5 years and randomly selected community controls were also recruited,” the research team shares in their Methodology section. “Since 2017, we invited previous study participants who could be contacted to enroll in a pilot study of the gut microbiome. In addition, we invited a household or community member of [Parkinson’s] patients to participate.” […]

(Beyond Pesticides, April 25, 2024) In a study from earlier this year, “Pesticides: An alarming detrimental to health and environment,” scientists compiled research from 154 articles regarding pesticide use and the adverse effects they have on the environment and human health. Among the effects of the harmful pesticides described is genotoxicity—the alteration of genetic material that results in the mutations in DNA that cause cancer.  The authors state that “genotoxins are mutagenic chemicals, and exposure to them increases the risk of developing tumors, hormonal changes, DNA damage, and changes in the ovaries and eggs, all of which leading to cancers… The risk of DNA damage surges with increased genotoxicity in people exposed to pesticides.” In addition, the National Institute of Health states that all “pesticides are highly biologically active chemicals. They may interact with DNA and damage its structure.” Despite these documented risks, pesticide use continues to surge.  While phased out to a considerable extent after being widely used in agriculture and residential areas, organochlorine pesticides (OCPs) like dichlorodiphenyltrichloroethane (DDT) or its breakdown compound dichlorodiphenyldichloroethylene (DDE) continue to show up as residues in the environment and food supply. Symptoms in humans that have been exposed to these chemicals include: seizures, […]

(Beyond Pesticides, April 24, 2024) On April 16, 2024, the U.S. Environmental Protection Agency (EPA) posted an “update” to the Draft Herbicide Strategy Framework (Draft Herbicide Strategy Framework to Reduce Exposure of Federally Listed Endangered and Threatened Species and Designated Critical Habitats from the Use of Conventional Agricultural Herbicides) that was released last summer, weakening aspects of the agency’s efforts to “protect” endangered species from herbicide use. The update outlines three types of modifications to the Draft Strategy, including “simplifying” its approach, increasing growers’ “flexibility” when applying mitigation measures, and reducing the mitigation measures required in certain situations. By reducing the stringency of the Strategy, advocates are again questioning EPA’s commitment to fulfilling legal requirements under the Endangered Species Act (ESA) or protecting endangered species and their habitats in the midst of an unprecedented rate of global extinction. ESA is celebrated as one of the most far-reaching conservation laws globally, credited with preventing the extinction of 99 percent of those species the government targets for protection, according to the U.S. Fish and Wildlife Service (USFWS). ESA establishes a framework to categorize species as “endangered” or “threatened,” granting them specific protections. Under ESA, EPA is required to consult with relevant agencies […]

(Beyond Pesticides, April 22, 2024) Today, on Earth Day, the future of the planet and the health of all its inhabitants come into focus from numerous human and ecosystem health perspectives, with particular concern for the health of the next generation—as childhood cancer continues to be a leading cause of death from disease among children. Many studies demonstrate an association between environmental or occupational pesticide exposure and the risk of childhood cancer in offspring. Taking Action in Your Community: On Earth Day, Beyond Pesticides invites communities to join together in its nationwide campaign to convert parks to organic land management practices through the Parks for a Sustainable Future program. Through this program, Beyond Pesticides works with park managers, bringing hands-on horticultural support to eliminate petrochemical pesticides and fertilizers and instead nurture soil organisms to cycle nutrients naturally while creating resilient landscapes that resist weeds, insects, and disease. This program outlines the steps to become a parks advocate and how Beyond Pesticides works with communities committed to safe parks and playing fields for communities, children, and pets. One major impetus for the Parks program are the many studies that find prenatal and early-life exposure to environmental toxicants increases disease susceptibility. For decades, studies have […]

(Beyond Pesticides, April 19, 2024) Parkinson’s disease (PD) and certain forms of dementia have been associated with exposure to pesticides, industrial chemicals, and air pollution for decades. But the mechanisms of disease progression have been unclear, and U.S. regulators have been reluctant to recognize the risks. Now neurologist E. Ray Dorsey, MD of the University of Rochester and researchers from the University of Alabama at Birmingham and Aarhus University in Denmark propose a new research paradigm based on tracking how toxicants cause neurodegeneration through inhalation and ingestion pathways. The paradigm, the authors believe, can be used to gain insight into how PD and a form of dementia known as Lewy body disease (LBD) are initiated as many as 50 years before the onset of symptoms. Dorsey and colleagues build on a recent theory that PD and LBD may be two versions of the same basic disease, both involving Lewy bodies in the nervous system. The group’s proposal was published in the Journal of Parkinson’s Disease in April. If its recommended research agenda produces the anticipated empirical support, the new paradigm will demand integration of many interdisciplinary lines of evidence showing that environmental exposures to synthetic chemicals may be the primary cause […]