Fluoride Action Network

The National Toxicology Program

This section is dedicated to the National Toxicology Program’s (NTP) long involvement with the issue of fluoride's toxicity. The NTP is the scientific research arm for U.S. regulatory agencies. It comes under the aegis of the National Institute of Environmental Health Sciences (NIEHS). The NIEHS, in turn, comes under the umbrella of the National Institutes of Health (NIH). -Updated May 2, 2023 (EC).

NTP 1990 Cancer Study: EPA Marcus on the downgrading of cancers

Fluoridegate: An American Tragedy

In 2013 David Kennedy, DDS, produced Fluoridegate: An American Tragedy, a classic documentary that is exquisite in capturing the battle that raged over the downgrading of cancers in the fluoride study overseen by the National Toxicology Program and published in 1990. Below we reprint the comments made by William Marcus, the senior toxicologist at the Environmental Protection Agency’s Office of Drinking Water, on these downgrades. Also, we add the comments from Stephen Kohn of the National Whistleblowers Association who explained how

the EPA went after Marcus with “a vengeance… like he was an enemy of the state”

In the 1980s the US Congress mandated the National Toxicology Program to conduct animal studies to determine if fluoride causes cancer. Battelle Columbus Laboratories were contracted to perform the studies that began in 1985 and ran for 2 years. In 1988 Battelle submitted their final report that included the finding of a dose-dependent increase of a rare liver cancer (hepatocholangiocarcinoma) in male & female mice and a small but statistically significant dose-related increase in osteosarcomas in male rats but not in the female rats. For the rare liver cancer, the first scientist to describe this cancer said that Battelle made a correct diagnosis. However, this rare liver cancer was reclassified by a government review panel as a non-cancer and one of the osteosarcomas was downgraded leading to the classification of “equivocal evidence of cancer”. There were also increases in oral and thyroid cancers, but they were not considered statistically significant. 

The politics that raged around this study.

William Marcus, the senior scientist in the Office of Drinking Water at the Environmental Protection Agency, expressed concerns about the “systematic downgrading” of cancers in the 1990 published study and requested that the EPA assemble an independent board of pathologists and others to review the data produced in the study. In the 2013 documentary Fluoridegate: An American Tragedy, Marcus has this to say about the study:

“… rats got cancer of the bone and they got a very unusual cancer of the liver. And that was extremely surprising. First of all to produce cancer of the bone in rodents is never seen because the time that you have between birth and death of a rodent is only 3 ½ to four years and it usually takes longer than that to produce a cancer in bone. The cancer of the liver is extremely rare and the fact that it happened meant that it was significant. This doesn’t happen. I wrote this memo in which I claimed that I thought fluoride was a carcinogen and that we had as much evidence with the animal studies to show that it was a carcinogen as we had with any of the other compounds [that EPA studied] and therefore should be treated as such.”

Also, three out of four in-vitro tests proved fluoride to be mutagenic, which Marcus said supported “the conclusion that fluoride is a probable human carcinogen.” The internal memorandum that Marcus wrote was leaked to the press. It caused embarrassment to senior EPA officials and Marcus was fired. 

“An Enemy of The State”

The National Whistleblowers Association represented Marcus in his two trials against the EPA and they won both. The EPA was forced to pay Marcus’ legal fees, 2 ½ years of back pay, and an undisclosed sum for damages to his reputation.

In the Fluoridegate documentary Stephen Kohn of the National Whistleblowers Association stated:

“… I do not know why the agency (EPA) did what it did to Dr Marcus. But I do represent whistleblowers and I can tell you they went after Dr Marcus with a vengeance, a vengeance. He was a board certified toxicologist with years of seniority, the most respected toxicologist in the agency with an international reputation. When he wrote that memo they went after him like he was an enemy of the state. They just hammered, and hammered, and hammered, and they went way over the line by destroying evidence and obstructing justice. And even after we won the first case where he was ordered reinstated they went after him again. And even though there were 2 court rulings finding retaliation they never touched or disciplined those agency officials involved. This case marks a black mark on the EPA and raises fundamental issues about scientific freedom and about fluoride and why this agency went against one of its most respected scientists on that issue.”

Robert Reich as Secretary of Labor in the Clinton administration upheld the decision of the Administrative Law Judge in 1994 who said that “the true reason for the discharge was retaliation.” Reich wrote that he found particularly disturbing that the trumped-up charges against Marcus were accepted by his supervisors “in the absence of any convincing documentation.”

By Ellen Connett
December 2014

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