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Editor’s note: The Defender is providing daily updates on the landmark trial pitting Fluoride Action Network against the U.S. Environmental Protection Agency. The trial started Feb. 1. To read previous coverage, click here.
The third day of the landmark fluoride trial included tense exchanges between scientists and the U.S. Environmental Protection Agency (EPA), as the agency sought to discredit statements made by a key witness for the plaintiffs and the plaintiffs called one of the EPA’s own experts to testify.
Food & Water Watch, Fluoride Action Network, Moms Against Fluoridation and other advocacy groups and individuals are suing the EPA in a bid to force the agency to prohibit water fluoridation in the U.S. due to fluoride’s toxic effects on children’s developing brains.
Expert witness Philippe Grandjean, M.D., Ph.D., returned to the stand for a second day to provide his assessment of several recently published studies finding no significant link between fluoride exposure and neurotoxicity.
Grandjean, chair of environmental medicine at the University of Southern Denmark and adjunct professor in environmental health at Harvard, is a leading world expert on environmental toxins. He has worked as an adviser to the EPA setting benchmark toxicity levels for mercury and lead.
In his first day of testimony, Grandjean provided a long history of research on fluoride’s neurotoxicity, including his own research linking fluoride exposure to cognitive deficits and key findings from the National Toxicology Program’s (NTP) report linking higher fluoride exposure to lowered IQ in children.
During cross-examination, attorneys for the EPA challenged Grandjean’s critiques of studies that didn’t find links between fluoride and neurotoxicity in children, sometimes drawing on statements from his deposition.
The agency attempted to show that some studies linking fluoride to neurotoxicity at low levels have a “risk of bias” and that one study in particular — the “Spanish study,” which did not find a link between fluoride exposure and lowered IQ among children in a birth cohort in northern Spain — was a “high-quality study” that ought to be taken seriously.
Grandjean disagreed and reiterated his analysis of those studies.
Next, the plaintiffs called one of the EPA’s expert witnesses, Stanley Barone, Ph.D., a risk assessment scientist from the Office of Chemical Safety and Pollution Prevention, 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 plaintiffs charge the EPA is failing to apply in the case of fluoride.
The day ended partway through his testimony and was scheduled to continue today.
“I’m very happy with how the evidence has come in the first three days with our first three expert witnesses,” plaintiff’s attorney Michael Connett told The Defender after the hearing.
He said the witnesses have established that the levels of fluoride exposure experienced by pregnant mothers in some fluoridated areas exceed the levels associated with significant decreases in IQ.
Second, he said, “I think the evidence has demonstrated that there is every reason to expect that some susceptible members of the population will be particularly vulnerable to fluoride’s neurotoxic effects and that any safety standards for fluoride really need to take that into account.”
“And certainly EPA needs to take that into account given the command of the Toxic Substances Control Act that susceptible populations be protected,” he added.
Expert witness defends analyses of key studies
Grandjean — known for his work on the neurotoxicity of mercury and lead for the U.S. Food and Drug Administration and other global health organizations — walked through issues of author and journal credibility and methods in one case and study design and data in another that compromised the findings and conclusions of the studies, he said.
Connett asked Grandjean about the “Spanish study” conducted by Jesús Ibarluzea, Ph.D. It is one of the primary cohort studies the EPA’s case relies on, which found no link between prenatal exposure to low levels of fluoride and lowered IQ among children in coastal Spain, but did find that fluoride exposure increased IQ for boys by an “implausible” 15 points.
“The study makes absolutely no sense,” Grandjean told Connett. He added that he wasn’t accusing the authors of fraud, but thought there had been a major error, perhaps in the lab analysis.
Ibarluzea himself was originally set to testify on behalf of the EPA, but after being deposed by the plaintiffs’ attorneys, he withdrew from further participation in the case. His deposition videos will be used as evidence by the EPA.
Finally, Connett asked Grandjean to walk the court through findings from a new pilot study by researchers at Tulane University that found children with chronic exposure to high levels of fluoride in drinking water made more errors on drawing and cognitive tests.
Connett ended his questioning by referring Grandjean back to the early studies by Kaj Roholm that identified a causal relationship between fluoride and skeletal fluorosis.
Based on the available evidence, Connett asked, “Do you think impacts on neurodevelopment are more threatening than on skeletal fluorosis?”
“Yes, I do,” Grandjean responded.
EPA tries to build its case
EPA attorneys spent much of the day building their case, which hinges on the idea that fluoride’s neurotoxicity is uncertain at low concentration levels based on the available evidence.
They used Grandjean’s testimony to cast doubt on the NTP’s findings and to suggest that Grandjean may be biased in his assessment of the Spanish study.
On the first day of Grandjean’s testimony, Connett had him review the outcomes of the high-quality studies, the vast majority of which found evidence of fluoride’s neurotoxicity at different levels, including low levels.
The EPA referred to a table from the NTP monograph showing the high-risk-of-bias versus low-risk-of-bias studies and argued that the studies used by the NTP showed a high risk of bias or were not statistically significant according to one method of analyzing that data — an assertion plaintiffs attorney countered in his re-directed questioning.
Throughout the day, Grandjean appeared annoyed by the line of questioning, particularly by the EPA’s attempts to find discrepancies in his statements by comparing them to statements made in his deposition, in response to questions he said were posed somewhat differently.
The EPA also pushed Grandjean to discuss the Danish cohort study, called the Odense study, where Grandjean and his colleagues did not find a statistically significant impact of fluoride exposure on IQ at low levels of exposure.
Grandjean explained that the Danish study, pooled with other studies, offered important insight into fluoride’s neurotoxicity, as he outlined the first day of testimony.
Finally, the EPA tried to get Grandjean to affirm the validity of the Spanish study by acknowledging that its authors were credible researchers — which Grandjean acknowledged, by acknowledging it was a high-quality study with low risk of bias, as evaluated by the NTP.
Then attorneys for the EPA suggested that because the NTP report contained a study that Grandjean didn’t find credible, he ought to find the NTP report itself questionable.
Federal Judge Edward Chen posed a key final question to the witness: “Is it common to find contrary studies after studies have shown toxicity from a chemical?”
Grandjean said this same phenomenon happened with lead, where some studies indicated lead had no toxic effect on children. He also said those studies were often funded by industry.
After the hearing, Connett summed up what the three witnesses argued: “The absence of a detectable effect doesn’t mean there’s no harm. Testimony thus far has shown that populations can differ significantly and different factors can influence how neurotoxicity manifests.”
Connett said variations in the association between fluoride and IQ in different populations would be expected, including null effects in some studies and findings of associations and others.
“So what may appear initially contradictory may in fact not be contradictory,” he said.
“The EPA really wants to see the low-dose studies finding significant effects. And if we don’t have low-dose studies finding significant effects, then they want to dismiss it entirely.
“The problem with that is when you’re studying lower exposures in a population, it’s much harder to detect an effect because you have lower exposure contrasts, which thereby reduce the power of the study to find the effect.
“It’s like using a lower powered magnifying glass — you’re not going to see as much as you will if you use a higher powered magnifying glass. When you’re studying populations that have more distinct exposure contrasts, you’re better able to tease out the effect of fluoride, which is one of the strengths of high-dose studies or higher-dose studies.
“So EPA on one hand wants to eliminate from its consideration all high-dose studies and then say there’s no risk based on low-dose studies, not finding the effect. And effectively what that means is EPA is discarding the higher powered magnifying glass in exchange for a lower powered magnifying glass, and then using that lesser sensitivity to claim there’s no effect.”
Is EPA following its own methodology for evaluating risk?
For the last 30 minutes of Friday’s testimony, Connett called Barone to establish the EPA’s methods for risk evaluation under the TSCA.
Barone, an EPA developmental toxicologist, was heavily involved in the TSCA’s first 10 risk evaluations. Before the trial, the plaintiffs asked him to establish the risk evaluation process for the record.
Their case rests in part on the allegation that the EPA is failing to follow its own risk-evaluation procedures in the case of fluoride.
Connett questioned Barone on key elements of the hazard assessment.
First, he asked Barone to confirm that to determine whether a chemical is a hazard — one step in the risk assessment process — there is no need to prove causation. To establish a chemical is a hazard, the EPA requires proof of association, not causation.
Next, Connett asked Barone whether the EPA had ever made a different hazard evaluation for high-dose versus low-dose exposure in all of the risk evaluations it had done to date under TSCA.
Barone said he was confused by the question.
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 doesn’t. The EPA doesn’t differentiate between high and low doses in determining whether something is a hazard.
Barone also confirmed that once something has been confirmed as a hazard, medium- and high-quality studies are then used to identify a hazard level.
These are points Connett also laid out in his opening remarks.
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