Chief operator Jamie McClendon poses for a portrait at the Marshall Water Treatment and Distribution Plant Nov. 4. (Les Hassell/Longview News-Journal Photo)

The city of Marshall hasn’t added fluoride to its water for about a year. The machinery that added the anti-cavity chemical to the public water supply quit working, and replacing it just hasn’t been a priority, the city’s public works director said.

Now, it likely never will be replaced. In the not-so-distant future, adding fluoride to public drinking water could be a thing of the past.

In 1946, Marshall was one of the first three cities in the United States — and the first in Texas — to add fluoride to its water supply, according to the Texas Department of State Health Services. At the time, scientific consensus held that the chemical would prevent tooth decay and strengthen enamel.

But new scientific research suggests that the health hazards of fluoridating water now outweigh its benefits, especially relating to children’s brain development. President-elect Donald Trump’s administration appears poised to pull the plug on the practice.

Robert F. Kennedy Jr., whom Trump has nominated to lead the Department of Health and Human Services, has pledged that the Trump administration will issue on Inauguration Day a call to end water fluoridation nationwide.

“Fluoride is an industrial waste associated with arthritis, bone fractures, bone cancer, IQ loss, neurodevelopmental disorders, and thyroid disease,” Kennedy wrote in a post on X. “President @realDonaldTrump and First Lady @MELANIATRUMP want to Make America Healthy Again.”

‘Great public health achievement’Fluoride strengthens tooth enamel and helps rebuild enamel that has worn down, according to the American Dental Association. The organization maintains that thousands of studies affirm the effectiveness of public water fluoridation and that fluoridation has reduced tooth decay by 25%.

The push for water fluoridation began in the 1930s and ’40s after Dr. H. Trendley Dean, a U.S. Public Health Service officer, discovered that people drinking water containing high levels of natural fluoride had dental fluorosis, which causes teeth to be stained brown. But he also learned that, when fluoride is added at levels low enough not to cause fluorosis, it had benefits in preventing cavities, according to the Centers for Disease Control and Prevention’s historical timeline on water fluoridation. From there, the race to add it to public water supplies was on.

A story about the town of Hereford, Texas, is credited with inspiring Americans to thirst for fluoridated water. In February 1943, Reader’s Digest and newspapers across the U.S. republished parts of an article from Collier’s magazine called “The Town Without a Toothache.” The town’s water contained naturally occurring fluoride, and local dentists noticed that people living there had virtually no tooth decay. Soon, this town’s water, believed to be miraculous, became a highly sought-after commodity.

In January 1945, the city of Grand Rapids, Michigan, became the first in the U.S. to fluoridate water.

The percentage of Americans who received fluoridated tap water trickled upward throughout the 20th and 21st centuries. By 1969, nearly 44% of Americans were drinking fluoridated water, and fluoridated toothpaste had been on store shelves for years. By 2012, 67.1% of all Americans had access to fluoridated tap water.

The CDC called water fluoridation “one of the 10 great public health achievements of the 20th century.” But not everyone agrees.

Questioning the benefitsCriticism of the practice was present at the outset. In 1944, the Journal of the American Dental Association quickly cautioned against adding fluoride to water, though the organization later recanted and ultimately became one of fluoride’s biggest champions.

About 10 years ago, the fluoride tide began to turn. In 2015, the U.S. Public Health Service lowered the recommended level of fluoride that cities should add to their water supplies to 0.7 milligrams per liter; most cities had been adding between 0.8 and 1.2 milligrams.

While fluoride is a naturally occurring mineral, and some bodies of water contain natural fluoride, most of the fluoride used in municipal water systems is “a hazardous waste byproduct of phosphate fertilizer production,” according to the Fluoride Action Network, an anti-fluoride advocacy group.

In spring 2016, Harvard Public Health’s magazine questioned whether studies attributing declines in cavities to fluoridated water were accurate. While the rate of cavities has declined in the U.S. since fluoride has been added to water, the rate also has dropped in countries that don’t fluoridate water, including Canada, France, Germany, Italy and more. The magazine’s researchers suggested that cavity rates have declined in those countries because fluoride has been added to toothpaste and dental supplements, which are available there as well.

The magazine also raised concerns about the health detriments of fluoride: Testing on lab animals determined that high levels of fluoride could be toxic to brain and nerve cells. Also, high levels of fluoride consumption in humans could be linked to “learning, memory and cognition deficits.” However, those studies focused on populations “with fluoride exposures higher than those typically provided by U.S. water supplies.”

Fluoride made headlines again in September, when a federal judge ruled that the Environmental Protection Agency must take action to reduce potential health risks from fluoride, CBS News reported. Citing a study from the National Institutes of Health, the judge ruled that fluoride can reduce children’s IQ “and is hazardous at dosages that are far too close to fluoride levels in the drinking water of the United States.”

East Texas cities respondCities across the state and nation already have stopped adding fluoride to their water systems. In September, Abilene temporarily suspended water fluoridation in light of the federal court ruling, according to KTXS. Buda, San Marcos and College Station stopped fluoridating their water years ago, according to the Fluoride Action Network.

Marshall still uses the water treatment plant where fluoridation began in the 1940s. Today, the equipment that pumped fluoride into the water supply still sits in a building there.

“We’re not considering adding it in. We’re not certain of the overall benefit,” said Eric Powell, Marshall’s director of public works.

As part of the city’s fluoridation implementation back in 1946, a six-year study was undertaken to determine how effective fluoride was at preventing cavities, the Marshall News-Messenger reported.

The Associated Press documented the results in a 1953 story: “X-rays of continuous-resident 6-year-olds here, compared with those in another Texas community without fluoride showed: The Marshall children have 57 percent fewer cavities than those of the same age group in the other city — Jacksonville, Texas, 70 miles away. More than 35 percent of the Marshall 6-year-olds have no cavities whatever. Only 13 percent of Jacksonville’s are cavity-free.”

The city of Tyler adds between 0.0401 to 0.225 milligrams per liter of fluoride to public water, less than the federal government’s recommended level and less than the Texas Commission on Environmental Quality’s recommendation of 4 milligrams per liter, said city spokeswoman Adriana Rodriguez. The city began the practice in 1985.

“Rest assured, we are vigilant in our duty to monitor any shifts in regulatory standards or advisories concerning water fluoridation,” Rodriguez said in a statement. “Should there be any modifications at the federal or state level, we pledge to promptly reassess our practices. Our priority remains the health and safety of our residents, all the while ensuring our compliance with prevailing legal requirements.”

Richard Yeakley, city of Longview spokesman, said the city “follows relevant state and national regulations, and if there are changes on those regulations on a state or national level, we will review those and adjust our practices accordingly.”

Removing fluoride from water supplies won’t affect the taste, color or odor of water, Powell said.

“I think most people probably don’t even know most water utilities are even adding it,” he said.