study found a linear dose-response relationship between fluoride and IQ, meaning that the lowered IQ effect occurred with any level of fluoride exposure and increased as the exposure increased.
There was then discussion of another study he co-authored which found that consumption of infant formula reconstituted with fluoridated water led to excessive fluoride intake and lower IQ scores for both boys and girls compared to their breastfed counterparts who received very low intakes of fluoride. Lanphear also pointed out that studies have consistently found that children in poorer areas were often exposed to more toxins, and the effects of fluoride exposures for their mothers during pregnancy and for the children during formula feeding could compound these effects, making the poor particularly vulnerable to fluoride’s effects.
In his testimony, Lanphear addressed the variability of findings in different studies - some find sex-differentiated responses to fluoride and others don’t, or some find neurotoxicity at lower levels and some at higher levels. Lanphear said that the same variability exists in toxicity studies for lead, where some studies find greater effects in boys and others in girls. The overall indication is that lead, like fluoride, is toxic and that other factors drive sex differentiation in a particular context.
The discussion then focused on how fluoride could increase hypothyroidism rates in pregnant women, impacting fetal brain development, and how these effects were both increased if the mother was iodine deficient. Lanphear co-authored key studies on these subjects. He pointed out that the 2006 National Research Council report recognized that fluoride was a thyroid disruptor. He also noted that iodine deficiency has been increasing in the United States. FAN attorney Michael Connett asked, “Is there any dispute that hypothyroidism can lead to a lower IQ?” Lanphear: “No.”
Lanphear wrapped up his testimony by discussing his work measuring maternal urinary fluoride concentrations of pregnant women. He testified that an average woman living in a fluoridated community has fluoride levels in their urine twice as high as an average woman living in a non-fluoridated community. Connett asked, “What is the cause of this difference?” Lanphear responded, “Fluoridated drinking water.”
Journalist Derrick Broze interviewed Dr. Lanphear after his testimony on day two of the trial:
Fluoride Trial Interview - Dr. Bruce Lanphear
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The third expert witness called by FAN was Philippe Grandjean, MD, DMSc. Dr. Grandjean is a physician, a scientist, an internationally known expert in environmental epidemiology, an author, and both a professor of environmental health at the Harvard School of Public Health and the head of the Environmental Medicine Research Unit at the University of Southern Denmark.
Grandjean testified that he has been given grants and/or contracts to advise the EPA, the National Institutes of Health (NIH), the U.S. Food and Drug Administration (FDA), the World Health Organization (WHO), and numerous other government bodies for over 25 years. Dr. Grandjean said he had even been retained by the Department of Justice, which is representing the EPA in our trial, as an expert witness on environmental toxins.
Grandjean is the author or co-author of some 500 scientific papers and is perhaps best known worldwide for his research on the neurotoxicity of mercury, which involved studying the IQ of children born to mothers whose diet was high in mercury. This work led to defining the EPA’s safe regulatory levels for mercury in the diet and inspired downward revisions of methyl mercury exposure limits internationally.
Dr. Grandjean has authored or co-authored several studies and reviews on fluoride’s neurotoxicity, as well as the first benchmark dose analysis on fetal fluoride exposure which found that a maternal urine fluoride concentration of 0.2 mg/L, which studies show is exceeded 4 to 5 times in pregnant women living in fluoridated communities, was enough to lower IQ by 1 point. In his testimony, Grandjean confirmed that the fluoride the mother is absorbing will pass into the child’s brain. “You only get one chance to develop a brain. Once it’s harmed, there’s nothing you can do.” Grandjean says.
Attorney Connett showed a quote from EPA scientist Kristina Thayer, who provided testimony in the first phase of the trial. Dr. Thayer said she believes that animal data supports the biological plausibility of fluoride causing neurotoxic effects in humans. Grandjean agreed with Thayer’s opinion. Connett asked Grandjean about the EPA’s opening statement in which they claimed that Chinese fluoride studies were looking only at very high levels of fluoride exposure. Grandjean insisted this was not the case, saying that even at lower levels there was evidence of cognitive impacts from fluoride, confirming outright that he felt neurotoxicity was definitely a hazard of fluoride exposure.
Connett then asked about NTP’s May 2022 final draft report, which included Grandjean’s own studies and found lower IQ in children exposed to fluoride during fetal development. Connett specifically asked about the EPA’s claim that the NTP’s findings were “driven by studies looking at fluoride levels of 7.0 ppm and higher.” Dr. Grandjean replied, “They must have a misunderstanding because that’s certainly not correct.” He then agreed with the NTP authors’ statements that some of the higher-quality studies that found harm were done in optimally fluoridated communities.
Dr. Grandjean then confirmed that over a lifetime of dealing with evidence on neurotoxicants, “Fluoride probably has the largest body of evidence of any of our known or suspected neurotoxicants.” Agreeing with NTP’s finding that the consistency of association of lower IQ in children in five different countries rules out the possibility that there is a common factor other than fluoride exposure that can account for this outcome, Dr. Grandjean stated: “When it comes to fluoride, we have a massive amount of evidence. There is something very serious going on here that we must take seriously.”
Fluoride Trial Interview - Dr. Philippe Grandjean
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Next to take the stand was EPA’s expert witness Stanley Barone, Ph.D., a risk assessment scientist from the EPA Office of Chemical Safety and Pollution Prevention, testifying as FAN’s fact witness to establish EPA’s methods for risk evaluation under the Toxic Substances Control Act(TSCA).
Through questioning, Barone explained the EPA’s risk assessment method - the method FAN says EPA is failing to apply in the case of fluoride. As an EPA developmental toxicologist, Barone was heavily involved in TSCA’s first 10 risk evaluations. Before the trial, the plaintiffs asked Barone to establish the risk evaluation process for the record.
Connett questioned Barone on key elements of the hazard assessment. He asked Barone to confirm that to determine whether a chemical is a hazard - step one in the risk assessment process - there is no need to prove causation. Barone agreed that to establish that a chemical is a hazard, EPA requires proof of association, not causation.
Next, Connett asked Barone whether EPA had ever made a different hazard evaluation for high-dose versus low-dose exposure in any of the risk evaluations it had done to date under TSCA. Barone said he was confused by the question. Judge Chen interjected to pose the question himself. “In the hazard evaluation, is it a binary decision?” Barone said it was. In other words, a chemical poses a hazard or it