Compiled by Michael F. Dolan, PhD
Facing a Shortage of Fluoride, Maryland Water Systems Opt to Distribute a Reduced Concentration of the Harmful Chemical That is Not Considered Effective
In reporting a decline in the availability of hydrofluorosilicic acid, the fluoride product they add to their water supplies, Washington Suburban Sanitary Commission (WSSC) Water and the Baltimore City Department of Public Works have announced that they will reduce the fluoride concentration from 0.7 milligrams per liter (mg/L) to 0.4 mg/L, even though that concentration is considered to have no therapeutic effect, even by fluoridation proponents. This raises the obvious question of why expose the public to a pollutant in their drinking water that no longer serves even a presumed purpose.
Pro fluoridation public health officials continue to recommend a concentration of 0.7mg/L and consider a concentration of 0.6 mg/L or lower to be ineffective. In a 2020 essay in the American Water Works Association magazine Opflow, then U.S. Centers for Disease Control and Prevention (CDC) fluoridation engineer Kip Duchon wrote, “When water has a fluoride content of less than 0.6 mg/L, it’s insufficient to improve oral health.”
Recently, a similar finding occurred in the Ontario, Canada county of Lambton, where fluoridation had been suspended for water system repairs. Sarnia News Today reported on April 22nd that Lambton Public Health “is required to notify impacted residents when fluoride concentrations in their water supply fall outside the therapeutic levels (0.6–0.8 ppm) for more than 90 consecutive days.”
American Dental Association fluoridation spokesperson, Dr. Scott Tomar, told the Associated Press on April 8th, “Based on the best available information we have, below 0.5 milligram per liter, you’re probably not going to see effective preventive exposure.”
According to its April 7th press release, WSSC Water serves 1.9 million customers in Montgomery and Prince George’s counties. The Baltimore system serves Baltimore City, Baltimore County and Howard County. Press reports did not indicate the number of customers served there, but the CDC’s My Water’s Fluoride on-line database indicated that the Baltimore City system serves over 1.3 million people.
NBC News 4 in Washington reported on April 8th that there have been significant disruptions to the fluoride market in recent months.
“One of the major manufacturers of fluoride is in Israel, and they have had some significant operational challenges due to the ongoing conflict in the Middle East,” said Chuck Brown of WSSC Water, according to NBC News 4.
In a comment to South Carolina Public Radio, Brown said of the reduced amount of fluoride available, “we feel confident that we’ll be able to stretch that out for a couple of more Months.”
From press accounts it appears no public officials were asked by reporters, nor made any attempt on their own, to justify the provision of the ineffective 0.4 mg/L concentration.
The Fluoride Action Network’s (FAN) Executive Director, Stuart Cooper, has collected additional information about the current fluoridation chemical shortage and the FAN team is looking further into the cause, which is impacting multiple communities across North America and appears to be effected by factors that may be unrelated to Israel. Once we have more information, we’ll share it.
Wisconsin Fluoride/IQ Study “Policy Advocacy Masquerading as Science,” Scholar-Activist Says
A recent paper by social scientists that reported finding “no evidence that community water fluoridation is associated with lower adolescent IQ or cognition later in life,” was designed to make such a null result “nearly inevitable,” according to a popular scientist and activist.
Writing on April 14th on his Popular Rationalism substack site, James Lyons-Weiler takes a withering look at J.R. Warren and others’ April 13th paper in the Proceedings of the National Academy of Science on the Wisconsin Longitudinal Study, a long-term compilation of 1957 graduating high school seniors’ IQ scores.
“The authors describe their study as a response to evidence ‘cited in recent decisions to end CWF [community water fluoridation] in Utah, Florida, and elsewhere.’ The paper was designed after those policy decisions were made, to counter them,” writes Lyons-Weiler in a section of his essay entitled “Policy advocacy masquerading as science.”
The author notes fluoride exposure was not measured for any child in the study, but based on county-level data.
“[E]xposure is inferred from county-level historical records on when communities began water fluoridation programs – and, critically, from whether untreated wells in a county had naturally occurring fluoride levels deemed sufficient. Children whose counties had naturally sufficient well fluoride were classified as ‘exposed from birth,’” Lyons-Weiler writes. He goes on to list 10 critical flaws in the Warren report, most of which he labels fatal or severe to the report as a piece of scholarship.
One fatal flaw he sees is that the data are only those of high school graduates.
“Children who dropped out before graduation are entirely excluded. Neurotoxicant effects concentrate in the lower tail of the IQ distribution – precisely the children missing from the dataset,” Lyons-Weiler writes.
The author notes that the Warren paper fits into a pattern of public health literature that he has been following for years.
“It has a consistent shape: methodological choices that make null results structurally likely, paired with advocacy framing that presents these null results as definitive safety evidence. That pattern is what got fluoride into the American water supply without a prospective safety trail in the first place. It is the same pattern being deployed today to keep it there,” he writes.
FAN will be providing an additional in-depth bulletin in response to the Warren study, but please also visit our article on the study in the meantime.
Source: https://popularrationalism.substack.com/p/pnas-just-published-a-policy-
brief/comments
NOW AVAILABLE: The Digital Version of The Book “Fluoride Harms”
If you still haven’t gotten a copy of the new book, Fluoride Harm: Suppressed Science and Silenced Voices, now may be a great time to grab one since it has been made available in a convenient Kindle edition. Read it instantly on your phone, tablet, or computer.
Link to Purchase: https://www.amazon.com/Fluoride-Harm-Suppressed-Science-Silenced-ebook/dp/B0GNL96PJT/ref=tmm_kin_swatch_0
Enamel Researchers Consider the Problem With Fluoride
An international meeting called Enamel 11, held recently in Paris, brought water fluoridation experts together to educate enamel researchers on this public policy, including the serious consequences of chronic exposure to low-dose fluoride in drinking water. One even mentioned the prospect of ending the practice.
A group of international scientists including Prof. Pamela Den Besten of the University of California San Francisco, brought four experts together via webinars. Their meeting summary was published March 24th in Calcified Tissue International. The presentations can be viewed in their entirety at: https://youtu.be/vNo2xQYeK9I
The following quotes are from these authors’ published summaries of the presentations.
While Prof. Bruce Dye of the University of Colorado gave a conventional pro-fluoridation presentation, he acknowledged recent evidence that prenatal exposure to low-dose fluoride in drinking water can have a neurotoxic effect on the developing brains of children. He then added the standard tribute, noting, the “Centers for Disease Control and Prevention (CDC) …consider CWF [community water fluoridation] as one of the best cost-effectiveness public health achievements in history,” not just the 20th century.
Prof. Marília Afonso Rabelo Buzalaf, of the Bauru School of Dentistry, University of São Paulo had an exclusively tooth-centered perspective, seeing dental fluorosis as the only adverse effect of concern. She showed unwavering support for fluoridation although she did acknowledge that “Indeed, the main beneficial action of fluoride for prevention against caries is topical.”
In a presentation entitled, “The End of Fluoridation?”, Prof. Bruce Lanphear of Simon Fraser University presented the more serious adverse health concerns associated with community water fluoridation, saying as summarized:
“There are now numerous high-grade studies showing an inverse relationship between prenatal exposure to fluoride and IQ scores, followed by MUF [maternal urinary fluoride] which is a reliable measure of total fluoride exposure. The absence of a clear threshold, as is the case in fluoride related studies, is similar to findings related to most environmental toxicants. Indeed, protecting the population, particularly children, from the suspected toxicity of a substance requires a several-times difference between its use and the maximum acceptable dose, which is not the case with fluoride in tap water.”
The fourth speaker, Prof. Jean-Baptise Fini, physiologist at the French National Museum of Natural History, spoke in detail of the whole-body physiological effects of fluoride exposure, noting, “Fluoride’s structural similarity to iodide allows it to interfere with thyroid hormone synthesis through direct inhibition of the sodium/iodide symporter (NIS) and thyroid peroxidase (TPO), as well as indirect inflammatory and [other] pathways. This interference is markedly amplified by even mild iodine deficiency. In a large Canadian cohort the same increment in maternal urinary fluoride was associated with nearly 60% greater IQ loss in children of iodine-deficient mothers than in those of iodine-sufficient mothers.”
The subsequent discussion made clear that “Fluoride is not necessary for any physiological or cellular activity.”
At the population level, the authors noted, “[W]hereas the prevalence of dental caries is stable or increasing in most part of the world, it is possibly decreasing in Europe suggesting low direct relation (if any) between CWF and general caries prevalence.”
Source: https://doi.org/10.1007/s00223-026-01525-7
Low-Dose Fluoride Effects Found in Rainbow Trout
Concerned that sodium fluoride functions as an endocrine disrupter in aquatic animals, particularly affecting the thyroid hormone system, scientists from France, the Netherlands and Germany exposed early-stage rainbow trout (RT) (embryos and larvas) to environmentally relevant levels of sodium fluoride in their water, and found they exhibited a complex of adverse effects, according to a new report in Aquatic Toxicology.
Fish embryos were exposed to between one and 15 milligrams per liter (mg/L) of sodium fluoride for 15 to 23 days then examined for alterations of development, behavior, thyroid anatomy and eye development.
The authors found that exposure to as low a concentration of fluoride as 1 mg/L showed a significant reduction in head and body length. Larvas exposed to 5 mg/L fluoride showed a hyperactivity as measured in swimming speed in contrast to the 15 mg/L group that showed a significantly slower swimming speed. The group exposed to 5 mg/L also showed alterations to eye structure and an increase in the number of thyroid follicles.
The authors concluded, “Our findings indicate that sodium fluoride, even at environmentally relevant and non-lethal concentrations, causes a variety of sublethal effects in early life-stages of RT. While we did not observe any impact on mortality, sodium fluoride exposure significantly altered key developmental, morphological, behavioral, endocrine, and immune parameters. Specifically, we noted delays in hatching, reduction in body and head size, and an increased incidence of malformations, all of which are consistent with fluoride-induced disruptions of bone development and tissue homeostasis already described in other fish Species.”
They also found “behavioral impairments, particularly hypoactivity, likely result from a combination of neurotoxic and sensory disturbances. Additionally, changes to thyroid follicle histology suggest endocrine disruption, providing a possible mechanistic explanation for the growth and behavior effects observed.”
“Together, these results underscore the need to consider fluoride not just as a dental additive or naturally occurring ion, but as a potential contaminant that can affect various physiological systems in aquatic organisms,” wrote the scientists.
They added, “Given the widespread presence of fluoride in freshwater ecosystems and the ongoing input from human activities, the present study emphasises the importance of re-evaluating the ecological risks of sodium fluoride especially for early developmental stages that are critical periods of vulnerability…Developmental anomalies such as variations in head and body size, eye development, behavior changes, effects on the thyroid hormone system, hatching rate and kinetics, as well as impacts on virus resistance resulting from early, short- term exposure to fluoride, provide important information for predicting potential risk both to human health and environmental integrity.”
Source: https://doi.org/10.1016/j.aquatox.2026.107815
•• Michael Dolan can be contacted at <mdolan.ecsn@outlook.com>