According to some, here's a reason to support Pinellas County's decision to cut fluoride from its drinking water: The idea started with the Nazis.
"History shows, actually, that in Nazi Germany, one of the first things that they did was add fluoride to the water in the ghettos where the Jews stayed," Matt Leffler of Clearwater told the County Commission Tuesday before it voted 4-3 to stop fluoridating water for 700,000 residents.
Similar comments piled up on the St. Petersburg Times' website.
One reader declared the Nazi-fluoride connection "an absolute historical fact." Others linked to sources they found on the Web.
The Nazis killed millions of Jews during the Holocaust and were known for chemical tests and inhumane medical experiments. But did that include adding fluoride to water?
We tracked down roots of these claims on the Web, reached out to Holocaust historians, contacted well-known critics of water fluoridation, and read book excerpts and magazine articles and news stories. And we can tell you: There's no teeth to this claim.
"We have done our level best to discourage opponents of fluoridation from using this emotive argument," said Paul Connett, a chemist who directs the anti-fluoridation group Fluoride Action Network and recently co-authored a book called The Case Against Fluoride.
"The historical evidence for this assertion is extremely weak," Connett added. "It is sad that the U.S. media has done such a bad job of educating the public on this issue that it is so easy for crazy ideas to fill the vacuum."
So where does the story come from?
Andy Hollinger, who handles media relations at the U.S. Holocaust Memorial Museum, tried not to laugh as we asked our questions.
"I can almost guarantee you that is indeed an urban myth," he said. "... That sounds like Conspiracy Theory 101."
But he humored us, putting historian Patricia Heberer on the phone. Her expertise is the German medical community, including Holocaust experimentation.
Most Nazi medical experiments, she said, had two themes: new drugs and treatments for common battlefield ailments, from war wounds to typhus, or the more infamous effort to underpin Nazi racial ideas, such as Josef Mengele's twin studies. None of the experimentation that she knows of involved fluoride — for mind control or for healthy teeth.
But she had heard a similar Cold War-era theory. It wasn't about the Nazis fluoridating water. It was the Communists.
In 2009, two scientists wrote a book about the fluoride "wars," as they called it, dedicating more than 30 pages to conspiracy theories and their origins. We spoke with one of them.
"The World War II death camp statement is an absurd lie," authors Jay Lehr said.
Given the topic, it seems appropriate to conclude with Wikipedia, where we found mention of Nazis and fluoride — in an article listing conspiracy theories: Fluoridation is alternately part of a "Communist, Fascist or New World Order or Illuminati plot to take over the world." It was "pioneered by a German chemical company to make people submissive to those in power." It was "used in Russian prison camps and produces schizophrenia."
Our Holocaust historian knew of no such project. Two book authors who researched the topic, one a journalist, the other a hydrologist, found no credible evidence of such a connection. A leading anti-fluoridation activist repudiates the story.
So we can confidently declare this claim Pants on Fire!
This ruling has been edited for print. Read the full version at PolitiFact.com/Florida.