Fluoride in Water: The Theory, the Science, the 2025 Bans.

The fluoride-in-water debate is not a single argument. It is three arguments layered on top of one another: a scientific argument about neurological harm at current exposure levels; a historical argument about how a waste-byproduct of aluminum smelting and uranium enrichment became a municipal-health intervention; and a political argument about informed consent in mass medication. Each of the three has had a decisive document released since August 2024. Taken together, they are the reason the 80-year US policy is unwinding, state by state, for the first time in the program's history.

Where it started

The story of US water fluoridation begins in Colorado Springs in 1901, when a young dentist named Frederick McKay arrived to open a practice and noticed that a substantial share of his new patients had teeth with strange brown and white mottling. Over the next three decades, McKay's investigation of what would come to be called "Colorado brown stain" — and what is now known as dental fluorosis — traced the condition to naturally elevated fluoride levels in the regional water supply. By the 1930s, McKay and the US Public Health Service dentist H. Trendley Dean had reversed the framing: the same fluoride that produced mottling at higher concentrations appeared, at lower ones, to reduce the incidence of dental caries. Dean's 21-city comparison studies, published 1938–1942, formed the statistical basis for the claim that fluoride in water at 1.0 mg/L reduced cavities without producing meaningful fluorosis.

The other line of history — the one independent researchers argue matters more — runs through industry. Gerald J. Cox, a biochemist at the Mellon Institute in Pittsburgh, had been funded by the Aluminum Company of America (ALCOA) to investigate fluoride's biological effects. Aluminum production is a prodigious source of fluoride waste; fluoride emissions from smelters had been the subject of damaging agricultural-liability lawsuits since the 1920s. Cox proposed publicly in 1939 that fluoride — far from being merely a toxic industrial byproduct — was an essential nutrient whose addition to public water supplies would protect children's teeth. Cox's employer, ALCOA, and its longtime corporate attorney Oscar Ewing — who became Federal Security Administrator, the cabinet-rank official overseeing the US Public Health Service, in 1947 — are the institutional link researchers point to when they describe fluoridation as an industrial-waste-disposal problem that became a public-health program.

The Manhattan Project compounded the industrial interest. Uranium enrichment at Oak Ridge, Tennessee used uranium hexafluoride gas as its working fluid; fluoride handling and worker exposure generated a toxicology research need that did not exist at peacetime scale. Harold C. Hodge, then a young pharmacologist at the University of Rochester, was brought into what came to be called "Program F" to study fluoride's effects on Manhattan Project workers and the populations near uranium-processing facilities. Declassified documents released in 1997, and investigated in depth by Christopher Bryson in his 2004 book The Fluoride Deception, show that Program F research was structured partly around the atomic program's liability exposure. Hodge went on to become the first chair of the US Public Health Service's committee on fluoridation — the federal body that in 1950 gave the national program its formal endorsement — and one of the most publicly prominent advocates of municipal fluoridation for the next three decades. The institutional bridge between atomic-industry fluoride toxicology and public-health fluoridation policy is, in the person of Harold Hodge, direct.

The Grand Rapids trial began January 25, 1945, six months before the first atomic test at Alamogordo. It was designed as a 15-year controlled comparison against the neighboring city of Muskegon, which would remain un-fluoridated as a control. Muskegon abandoned its control status and began fluoridating in 1951, before the planned trial had produced final results — an event researchers argue undermined the epistemic status of the trial that was supposed to establish the program's safety and efficacy. By 1951, federal endorsement was in place. By 1960, most major US cities were fluoridated. By 2025, the US Centers for Disease Control estimated that about 63 percent of the US population on community water systems received fluoridated water.

What the theory claims

The umbrella "fluoride conspiracy" is a family of related claims. At minimum, it holds that the officially accepted US narrative — a naturally occurring mineral, identified by dental science in the 1930s, added to water supplies since 1945 for cavity prevention, demonstrably safe at 0.7 mg/L — is substantially incomplete. The documented industrial and atomic origins, the firings of internal researchers who produced unfavorable findings, the 2024 NTP report held back for nine years, and Judge Chen's 2024 TSCA ruling are offered as the evidence for that incompleteness.

The industrial-waste framing argues that the compound being added to US drinking water — not naturally occurring calcium fluoride, but primarily hydrofluorosilicic acid, a byproduct of phosphate fertilizer production — was a commercial liability before it became a public-health product. Phosphate-rock processing at facilities like the Mosaic Company's operations in central Florida generates the silicofluoride compound as a scrubber residue. The industrial economics of disposing of that waste as a drinking-water additive are, researchers argue, sufficient to explain most of the institutional resistance to revisiting the program. Paul Connett's The Case Against Fluoride (2010), co-authored with James Beck and H.S. Micklem, makes this case in its most comprehensive form.

The neurotoxicity framing argues that fluoride, at concentrations achievable through combined exposure from water, food, dental products, and environmental sources, affects the developing brain. The Harvard 2012 meta-analysis (Choi, Grandjean et al.) aggregated 27 Chinese studies and found an inverse relationship between fluoride exposure and children's IQ. The 2017 Bashash et al. study in Environmental Health Perspectives, a prospective cohort of 299 mother-child pairs in Mexico, found a statistically significant inverse relationship between maternal urinary fluoride and child IQ. The 2019 Green et al. study in JAMA Pediatrics, a Canadian cohort, found similar effects at North American exposure levels — not the elevated Chinese or Mexican levels — and triggered the editorial controversy that in turn produced the institutional pressure leading to the NTP's release of its delayed systematic review. The NTP August 2024 report concluded with "moderate confidence" that exposures above 1.5 mg/L are associated with lower IQ in children.

The informed-consent framing argues that, regardless of the scientific dispute, adding a pharmacologically active substance to a public water supply constitutes mass medication without individual consent. This framing does not require any particular position on the neurotoxicity question; it holds that the ethical default for adding bioactive compounds to a publicly consumed resource should be opt-in rather than opt-out. Most of continental Europe has, on this basis, declined to fluoridate its water: Germany, the Netherlands, Sweden, Denmark, Norway, Finland, France, Switzerland, and Austria among others either stopped fluoridation after initial trials or never started. The relative health of those populations' teeth, by WHO data, has not diverged materially from the US in the decades since.

The variations

Inside the umbrella argument, specific sub-framings have their own evidentiary bases. The pineal-gland framing, associated with British researcher Jennifer Luke, argues that the pineal gland — the brain structure that produces melatonin and that Descartes famously called "the seat of the soul" — accumulates fluoride at higher concentrations than other soft tissues. Luke's 1997 PhD dissertation at the University of Surrey reported pineal fluoride concentrations averaging 9,000 mg/kg (higher than typical bone concentrations) in cadaver samples, and hypothesized that calcification of the gland by fluoride might affect melatonin production and circadian regulation. Luke's work is the most-cited basis for the colloquial framing of fluoride as "dumbing down the population" in an embodied, not merely cognitive, sense.

The thyroid framing observes that fluoride is chemically similar to iodine and argues that fluoride exposure produces subclinical or clinical hypothyroidism by displacing iodine. The 2015 Journal of Epidemiology & Community Health study by Peckham et al., examining UK general-practice data, found that areas with fluoridated water had roughly 30 percent higher rates of hypothyroidism diagnosis than non-fluoridated areas. This study has been subject to methodological critique; researchers argue the underlying iodine-displacement mechanism has been documented since the 1950s in occupational and therapeutic fluoride-exposure studies in aluminum workers and thyrotoxicosis patients.

The skeletal-fluorosis framing observes that chronic fluoride exposure at levels well below the toxic threshold has been documented to affect bone metabolism — producing reduced bone density, joint pain, and in severe cases crippling skeletal fluorosis, most visibly in Indian and Chinese populations drinking from naturally high-fluoride wells. Researchers argue that the US's rising rates of osteoarthritis and unexplained joint pain in young adults have not been adequately studied for fluoridation correlation. The 2006 National Research Council report Fluoride in Drinking Water: A Scientific Review of EPA's Standards concluded that the then-EPA maximum contaminant level goal of 4 mg/L was not protective against severe skeletal fluorosis and recommended it be lowered — a recommendation the EPA did not implement for more than a decade.

The historical-origins framing, most associated with Bryson's 2004 book, argues that the disclosure of Manhattan Project Program F documents and the Mellon Institute / ALCOA funding trail constitute a direct historical connection between industrial-waste-disposal interest and the formation of municipal fluoridation policy. Researchers in this framing argue that it is not necessary to prove present-day harm to establish that the program's origin has not been honestly disclosed.

The Mullenix case

The modern debate's decisive internal-research moment came in the early 1990s at the Forsyth Dental Center in Boston. Phyllis Mullenix, a toxicologist who led Forsyth's Department of Toxicology, had been invited to investigate fluoride's neurological effects in rats. Her study, completed with colleagues Pamela DenBesten, Ann Schunior, and William Kernan, was published in 1995 in the peer-reviewed journal Neurotoxicology and Teratology. It reported that fluoride exposure produced behavioral changes in rats and that fluoride accumulated in brain tissue at concentrations previously not anticipated. The study, funded in part by the National Institutes of Health, was one of the first rigorous animal-model studies of fluoride's neurotoxicology to be conducted at a dental-research institution.

Mullenix was terminated from Forsyth in 1994, while the paper was still in peer review. In subsequent interviews — most extensively in Bryson's 2004 book and in her own later testimony — she described a pattern in which her preliminary findings prompted pressure from Forsyth leadership and dental-public-health institutional stakeholders to suppress or soften the paper's conclusions. After her firing, she was unable to obtain continued NIH funding; her subsequent career was in peripheral toxicology roles outside the dental-research mainstream. The Mullenix case is cited by the Fluoride Action Network and its litigators as the modern template for the institutional response pattern to adverse fluoride findings.

A decade later, a similar pattern played out at the National Research Council. The NRC's 2006 report — chaired by toxicologist John Doull — was produced at EPA's request and concluded that the then-EPA maximum contaminant level goal for fluoride (4 mg/L) was not protective against severe dental and skeletal fluorosis and that further research into lower-level neurological effects was warranted. Doull himself in subsequent interviews stated his view that the US fluoridation program was operating on assumptions that had not been adequately tested since the 1950s. EPA did not lower the MCLG in response to the report; the agency's subsequent 2011 proposal to lower the Public Health Service recommendation to 0.7 mg/L was framed around dental-fluorosis reduction rather than neurological risk.

The 2012 Harvard meta-analysis

In July 2012, Environmental Health Perspectives published "Developmental Fluoride Neurotoxicity: A Systematic Review and Meta-Analysis" by Anna L. Choi, Guifan Sun, Ying Zhang, and Philippe Grandjean. The paper aggregated 27 epidemiological studies — 26 from China, one from Iran — on fluoride exposure and children's cognitive outcomes. The pooled analysis found a standardized mean difference of -0.45 in IQ between high-fluoride and low-fluoride exposed children. Grandjean, the senior author, was a longtime Harvard professor of environmental health and one of the most published authors in developmental neurotoxicology.

The Harvard meta-analysis was criticized by US fluoridation proponents as applicable only to exposure levels well above the US standard. Researchers argue the criticism misses the point: the paper's existence and its findings established that developmental neurotoxicity from fluoride was a documented phenomenon in the peer-reviewed literature, not a fringe claim. The 2012 paper became the principal citation in the federal TSCA litigation that the Fluoride Action Network filed later in the decade. It is one of two documents most frequently cited in the congressional and state-legislature records underlying the 2025 fluoride bans.

What the 2024 NTP report actually said

The National Toxicology Program is the federal interagency program, housed at the National Institute of Environmental Health Sciences, that conducts systematic reviews of toxicological evidence on substances of public-health concern. Its fluoride review began in 2016 in response to a 2016 petition filed by the Fluoride Action Network and other groups. The draft was substantially complete by 2019. Internal emails later produced in federal litigation show that the draft's conclusions prompted back-and-forth between NTP staff and officials at HHS and the Public Health Service over the presentation of the findings. The final draft, released August 21, 2024, used the "moderate confidence" language for the finding that exposures above 1.5 mg/L are consistently associated with lower IQ in children. The report did not conclude that exposures at the 0.7 mg/L US standard were safe; it noted that the evidence base at lower levels was inconclusive rather than reassuring.

The nine-year delay between the original petition and the final release is one of the features of the NTP report most cited by researchers. Independent researchers argue that the delay is inconsistent with the program's ordinary timeline for systematic reviews and reflects institutional resistance at HHS. Dr. Linda Birnbaum, who directed the National Institute of Environmental Health Sciences from 2009 to 2019, has publicly confirmed that the NTP's fluoride review was subject to unusual political attention during her tenure.

The connections people make

Around the documented fluoride case — the Manhattan Project, the Mullenix firing, the Harvard meta-analysis, the 2024 NTP report, and the Chen ruling — independent researchers draw a larger set of structural connections. These connections are not the fluoride case itself. They are the claims the broader independent-research community brings into relation with it.

The industrial-waste-disposal pattern. Researchers argue that the fluoride program is one instance of a broader pattern in which industrial byproducts — initially liability problems — are recharacterized as public-health goods. Hydrofluorosilicic acid from phosphate-fertilizer scrubbers is the principal US fluoridation additive; similar pattern arguments are made regarding food-industry additives, pharmaceutical-waste streams, and the conversion of coal-ash into building materials. The structural argument is that when disposal costs exceed revenue potential, regulatory recharacterization becomes the economically rational path for the producer. Whether the fluoride case is the best evidence for that general pattern or merely the best-documented single case is an interpretive question.

The RFK Jr. HHS realignment. Robert F. Kennedy Jr.'s confirmation as Secretary of Health and Human Services on February 13, 2025, produced the first time in the program's history that the cabinet-rank official overseeing the US Public Health Service has been publicly committed to reversing the national fluoridation stance. Kennedy's pre-confirmation statements characterized fluoridation as "industrial waste" and indicated the Trump administration would act to remove fluoride from public water. Independent researchers read the Kennedy appointment as the single institutional change most likely to produce federal action on fluoridation in the program's 80-year history.

The European comparison. Most of continental Europe does not fluoridate its water. Germany, the Netherlands, Sweden, Denmark, Norway, Finland, Switzerland, Austria, France, and Belgium among others have either discontinued fluoridation programs or never implemented them. WHO dental-health statistics show that decay rates in fluoridated and non-fluoridated European countries have converged over the past half-century, with both declining at similar rates — a pattern researchers attribute principally to improvements in dental hygiene, toothpaste formulation, and diet rather than water-supply fluoride. The European comparison is one of the most-cited independent arguments against the claim that US water fluoridation is responsible for the country's dental-health outcomes.

The informed-consent and health-freedom framing. A separate cluster of adjacent arguments connects the fluoride case to other mass-medication or mass-intervention public-health questions. Researchers who have tracked the fluoride case since the 1990s have generally also tracked the 2020–2023 COVID vaccine program, childhood vaccine-schedule expansion, food-supply modifications including seed-oil and ultra-processed-food debates, and environmental-exposure questions including the atmospheric aerosol and geoengineering discussion. The shared intellectual frame is that the post-war US public-health establishment has operated a series of mass interventions whose risk profiles were not fully disclosed and whose informed-consent structures were not available to individual citizens. Whether the connections between these programs are structurally meaningful or merely political is the central interpretive dispute.

Key voices

• Dr. Paul Connett — retired professor of chemistry, St. Lawrence University; founder and longtime director of the Fluoride Action Network; co-author of The Case Against Fluoride (2010); the single most prominent independent researcher of the modern era.
• Phyllis Mullenix, PhD — Forsyth Dental Center toxicologist; 1995 Neurotoxicology and Teratology paper documenting fluoride neurotoxicity in rats; terminated from Forsyth in 1994 after producing preliminary findings.
• Michael Connett — attorney, Waters Kraus Paul Siegel; lead litigator on the TSCA case that produced Judge Chen's September 2024 ruling; the principal legal architect of the modern US fluoride case.
• Ellen Connett — Fluoride Action Network co-director; editor of the network's research database and weekly bulletin.
• Philippe Grandjean, MD, DMSc — Harvard School of Public Health; senior author of the 2012 meta-analysis; one of the most published authors in developmental neurotoxicology.
• Christopher Bryson — investigative journalist; author of The Fluoride Deception (2004); documented the Manhattan Project / Program F history and the Mullenix case.
• Bruce Spittle, MD — retired New Zealand public-health physician; editor of the journal Fluoride; author of Fluoride Fatigue (2008).
• Dr. Bill Osmunson, DDS — retired Oregon dentist; current director of Fluoride Action Network; former practitioner who has testified in state and federal proceedings on the dental-profession case for discontinuing fluoridation.
• Robert F. Kennedy Jr. — US Secretary of Health and Human Services (confirmed February 13, 2025); the first cabinet-rank official overseeing the US Public Health Service to publicly oppose fluoridation.
• Rep. Stephanie Gricius — Utah state representative; sponsor of Utah HB 81, the first US state law banning water fluoridation; signed March 27, 2025.

For connected historical and public-health material, see our coverage of the 2020–2023 COVID vaccine program (an adjacent institutional case in risk-disclosure and informed consent), stratospheric aerosol and geoengineering (the environmental-exposure framing), and alpha-gal syndrome (the vector-exposure and institutional-disclosure pattern).

The official position

The US Centers for Disease Control and Prevention continues to list community water fluoridation as one of the "ten great public health achievements" of the 20th century. The American Dental Association maintains its endorsement of fluoridation at the 0.7 mg/L recommended level. The US Environmental Protection Agency, as of April 2026, has not formally complied with Judge Chen's September 2024 order to engage in regulatory response under TSCA; the agency's appeal of the ruling is pending in the Ninth Circuit. The Department of Health and Human Services under Secretary Kennedy has instructed the Public Health Service to reassess the 0.7 mg/L recommendation in light of the NTP 2024 report; no revised recommendation has been issued as of this writing. The position of the pre-2025 federal establishment — that fluoridation at US recommended levels is safe and effective for cavity prevention — remains the formally published position of most dental and pediatric professional societies, though a growing number of state-level public-health departments have in 2025 begun to reconsider their endorsements.

Where it is now

As of April 2026, the fluoride-in-water question occupies an unusual political and scientific position: formally endorsed by most professional bodies, judicially ruled against at the federal district level, legislatively reversed in two US states, and undergoing active reassessment at the cabinet level. Utah's ban took effect May 7, 2025. Florida's ban took effect July 1, 2025. Bills patterned on Utah HB 81 and Florida HB 651 have been introduced in 2025 in Ohio, Kentucky, South Carolina, Arkansas, New Hampshire, Nebraska, and Louisiana; at least two of those are expected to reach their governors' desks before the end of 2026. Municipal-level fluoridation discontinuations — which had been occurring at a rate of a handful per year for most of the past two decades — accelerated to more than 100 documented municipal votes or administrative actions in the 12 months following the NTP report's August 2024 release.

The underlying scientific question — whether fluoride exposure at the US recommended level of 0.7 mg/L produces developmental neurotoxicity at the population level — is the question the federal appeal of Judge Chen's ruling, and the federal regulatory response if that appeal is denied, will have to address. The 2024 NTP report is the single most important document the next phase of that adjudication will rest on. The political and scientific infrastructure of water fluoridation, in place for 80 years, is for the first time in active reassessment.

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Frequently asked questions

When did water fluoridation start in the United States?

January 25, 1945, in Grand Rapids, Michigan — the first US municipal water fluoridation program. It was designed as a 15-year controlled comparison against Muskegon, which abandoned its control status and began fluoridating in 1951. Federal Public Health Service endorsement followed in 1950. The current recommended concentration is 0.7 mg/L, revised from the earlier 0.7–1.2 mg/L range in 2015.

What is the Manhattan Project connection to fluoride?

Fluoride compounds — particularly uranium hexafluoride gas — were central to the uranium enrichment process. Worker-exposure liability produced a toxicology-research need. "Program F" at the University of Rochester, directed by toxicologist Harold Hodge, studied fluoride effects on Manhattan Project workers and nearby populations. Hodge later chaired the US Public Health Service's first committee on fluoridation and became one of the program's most influential advocates. Declassified Program F records released in 1997 and documented in Bryson's 2004 book established the link.

Is fluoride bad for you?

The 2024 NTP report concluded with "moderate confidence" that exposures above 1.5 mg/L are linked to lower IQ in children. The 2012 Harvard meta-analysis (Choi, Grandjean et al.) aggregated 27 studies and found an inverse relationship between fluoride exposure and children's IQ. Judge Chen's September 2024 ruling found that fluoridation at present US levels poses an "unreasonable risk" of developmental neurotoxicity under TSCA. Official dental-public-health bodies continue to hold the program is safe at 0.7 mg/L.

What did the 2024 NTP report say about fluoride?

Released August 21, 2024 after a nine-year delay. Final conclusion: "moderate confidence" that fluoride exposures above 1.5 mg/L are consistently associated with lower IQ in children. The report did not conclude that lower exposures were safe, only that the evidence base at lower levels was inconclusive. It is the first federal systematic review to formally find a neurotoxicity association.

What was Judge Chen's 2024 ruling on fluoride?

On September 24, 2024, US District Judge Edward M. Chen (Northern District of California) ruled that water fluoridation at present US levels poses an "unreasonable risk" of developmental neurotoxicity under TSCA. The ruling ordered EPA to engage in regulatory response. It is the first federal judicial ruling to find water fluoridation unlawful under a federal environmental statute. EPA has appealed; the appeal is pending as of April 2026.

Which US states have banned fluoride in 2025?

Utah became the first US state to ban water fluoridation — HB 81, sponsored by Rep. Stephanie Gricius, signed by Governor Spencer Cox on March 27, 2025, effective May 7, 2025. Florida became the second — HB 651 / SB 700 (the "Florida Farm Bill"), signed by Governor Ron DeSantis on May 6, 2025, effective July 1, 2025. Similar legislation has been introduced in 2025 in Ohio, Kentucky, South Carolina, Arkansas, New Hampshire, Nebraska, and Louisiana.

Who is Phyllis Mullenix?

A toxicologist who led the Department of Toxicology at the Forsyth Dental Center in Boston. Her 1995 paper in Neurotoxicology and Teratology reported that fluoride produced behavioral changes in rats and accumulated in brain tissue. She was terminated from Forsyth in 1994 after producing preliminary findings. Her story is documented in detail in Christopher Bryson's 2004 book The Fluoride Deception.

What does RFK Jr. say about fluoride?

RFK Jr., confirmed as US Secretary of Health and Human Services on February 13, 2025, has publicly called water fluoridation "industrial waste" and committed the Trump administration to moving to remove fluoride from public water. As HHS Secretary, he has reversed the department's long-standing endorsement of community water fluoridation and directed HHS agencies to reassess the 0.7 mg/L recommendation.

What is the Fluoride Action Network?

A non-profit research and advocacy organization founded in 2000 by Dr. Paul Connett. Its directors include Michael Connett (litigator), Ellen Connett, and Bruce Spittle. FAN has been the principal organizational plaintiff in the federal TSCA litigation that produced Judge Chen's September 2024 ruling. Its research-database website (fluoridealert.org) is the most frequently cited resource in the independent research community.

Is the fluoride-lowers-IQ finding settled?

The peer-reviewed literature — including the 2012 Harvard meta-analysis, the 2017 Bashash et al. Mexican cohort, the 2019 Green et al. Canadian cohort, and the August 2024 NTP monograph — supports an association between elevated fluoride exposure and lower children's IQ. The American Dental Association and CDC continue to hold that fluoridation at 0.7 mg/L is safe. The 2024 Chen ruling did not adjudicate the dental-benefit question. The policy dispute is what the 2025 state bans have begun to resolve legislatively.