Feedback and Analysis on the Safety of Fluoride in Drinking Water

Brian Oram, Licensed Professional Geologist
Featured Water Professional

Part of the KnowYourH2O Team philosophy is adherence to the scientific method. We are open to having our existing knowledge and any information we provide examined for the benefit of improving our own knowledge and in turn sharing it with our audience. 

The following article is in response to comments about our web page on Drinking Water and Fluoride submitted by Dr. Hardy Limeback

First a bit about Fluoride. Fluorine is a very active and dangerous gaseous element that is almost never found in elemental form but almost always in combination with other elements, producing fluoride compounds. Chemical compounds of fluoride occur naturally in the environment and they commonly are associated with weathering or the erosion of rock and soil. Fluorides get into the environment through the dissolution of fluoride minerals as groundwater moves through an aquifer and by volcanic emissions. Organic fluorides can be found in vegetables, fruits, and nuts. 

Fluoride can be accidentally released to the environment through a combination of man-made or related activities, such as: mining, manufacturing aluminum, the manufacturing of glass and steel, rodent poisons, and processing phosphate ores. Fluoride is also intentionally added to some city water systems under the assumption or hypothesis that this will aid in preventing tooth decay (it hardens the enamel of the teeth).

Comment 1

Dr Hardy Limeback:

“90% of the cities in the US and Canada (as well as the Rep. of Ireland, parts of the UK, New Zealand and Australia) use the phosphate fertilizer industrial waste product hydrofluosilicic acid (or its sodium salt), which is contaminated with toxic heavy metals such as arsenic, lead, mercury and even radionuclides.”

KYH2O Response | Agree with Additional Context

In preparing our response, we learned more:

1. The production of phosphate fertilizer does produce fluorosilicic acid.   

Online we found the following, this very charged statement: “Unfortunately the free preview of the fluoride awareness video didn’t begin by explaining that approximately fifty years ago, the phosphate mining industry discovered an alternative to the simple disposal of the highly toxic hydrofluosilicic acid industrial waste product (also known as fluorosilicic acid) from producing phosphate rock fertilizer.  That alternative was to SELL the hazardous waste to municipalities throughout the U.S. to be dumped into our municipal water supplies, generating billions of dollars of income for the industry on the backs of those citizens’ health. An earlier source was waste from nuclear weapons.”  (Source

Video: Mr Fluoride Song For Change Song for Safe Clean Water

2. MSDS Sheet for Fluorosilicic acid.

We searched and reviewed the MSDS / SDS for fluorosilicic acid and yes it is a HAZARDOUS Waste. (View PDF)

3. From the CDC, we learned that the following are the primary sources of fluoride used in additives. 

“Most fluoride additives used in the United States are produced from phosphorite rock. Phosphorite contains calcium phosphate mixed with limestone (calcium carbonates) minerals and apatite—a mineral with high phosphate and fluoride content. It is refluxed (heated) with sulfuric acid to produce a phosphoric acid-gypsum (calcium sulfate-CaSO4) slurry. The phosphoric and fluoride gasses that are released in the process are then separated. The fluoride gas is captured and used to create fluorosilicic acid.” So – Yes, acid is produced

“According to the American Water Works Association Standards Committee on Fluorides, the sources of fluoride products used for water fluoridation in the United States are as follows:

  • Approximately 90% are produced during the process of extracting phosphate from phosphoric ore.
  • Approximately 5% come from the production of hydrogen fluoride or sodium fluoride.
  • Approximately 5% come from the purification of high-quality quartz.

Since the early 1950s, FSA (FluoroSilicic Acid) has been the main additive used for water fluoridation in the United States. The favorable cost and high purity of FSA make it a popular additive. Sodium fluorosilicate and sodium fluoride come from processing FSA (fluorosilicic acid), or from processing hydrogen fluoride. FSA can be partially neutralized by either table salt (sodium chloride) or caustic soda (NaOH, sodium hydroxide) to get sodium fluorosilicate. If enough caustic soda is added to completely neutralize the fluorosilicate, the result is sodium fluoride. About 90% of the sodium fluoride used in the United States comes from FSA.” (Source

Yes – It appears a hazardous waste is processed and converted into sodium fluorosilicate.  The MSDS sheet for sodium fluorosilicate (View PDF) states the following:

Potential Acute Health Effects: Hazardous in case of skin contact (irritant), eye contact (irritant), ingestion, or inhalation. Severe over-exposure can result in death.

Potential Chronic Health Effects:  CARCINOGENIC EFFECTS: 

     ACGIH (Ameridan Conference of Governmental Industrial Hygienists) – A4 (Not classifiable for human or animal)

     IARC (International Agency for Research on Cancer) – 3 (Not classifiable for humans)

In other words, the agencies have not yet determined whether sodium fluorosilicate has any carcinogenic effects or not. 

MUTAGENIC EFFECTS: Not available. TERATOGENIC (causes development problems) EFFECTS: Not available. DEVELOPMENTAL TOXICITY: Not available. Repeated exposure to a highly toxic material may produce general deterioration of health by an accumulation in one or many human organs.

Special Remarks on other Toxic Effects on Humans: Acute Potential Health Effects: 

Skin: Causes mild to moderate skin irritation. Symptoms may include redness, burning sensation (feeling), and sometimes ulcers. 

Eyes: Causes moderate to severe irritation. 

Inhalation: It can irritate the nose, throat, lungs causing coughing, wheezing and/or shortness of breath.

Ingestion: Harmful if swallowed. It is toxic by oral exposure route. Symptoms of acute ingestion include a salty or soapy taste in the mouth, excessive salivation, nausea, abdominal cramps, vomiting, diarrhea, thirst. 

It may also affect behavior/central nervous system (central nervous system depression, muscle weakness, tremors or spasms, ataxia, convulsions) and may also cause disturbed color vision, kidney damage, liver damage, bleeding from the stomach, shortness of breath, loss of consciousness or death. 

Chronic Potential Health Effects: 

Skin: Repeated or prolonged skin contact may produce pustular rash. 

Inhalation or Ingestion: Prolonged or repeated exposure may cause excess respiratory, cardiac, and gastrointestinal disturbances, and chronic bronchitis. 

It may also cause liver and kidney damage, fluorosis and osteosclerosis. Fluorosis can cause mottling of teeth.

Treatment chemicals used in the fluoridation process must meet NSF/ANSI 60.  This NSF (National Sanitation Foundation) fact sheet on fluoride provides significant clarification on the history of fluoride usage, NSF certification of chemicals used in the fluoridation process, and much more (View PDF). 

SO Yes, uncontrolled exposure to sodium fluorosilicate can cause chronic and acute health problems that are significant. 

Comment 2

Dr. Hardy Limeback: Reaction of Fluoride with Teeth

“This is a very complex process. Topical fluoride exposure during repeated cycles of demineralization and remineralization will allow fluoride to be incorporated into the surface enamel, which makes it more resistant to decay by dental plaque acids. Fluoride exposure during tooth development (from ingested fluoride) makes the outer enamel hypermineralized and more brittle. The immediate subsurface enamel is hypomineralized and biomechanically weak and this enamel is MORE susceptible to dental decay. There is no evidence that ingesting fluoride helps with tooth decay- it only hurts humans when ingested.”

KYH2O Response | Mixed

Here is additional information regarding dental fluorosis which “is a pathologic condition characterized by hypomineralization of the enamel due to excessive exposure to fluoride during enamel mineralization.”

Additionally, one reviewer of our team had the following personal anecdotal observation: “I would disagree from personal experience.  Detroit, where I grew up, fluoridated its water.  Except for my wisdom teeth which came in after I left Detroit, I have had no cavities.  My local dentist took one look at my mouth and said I did not grow up in NE PA (Northeastern Pennsylvania), which does not fluoridate its water, because all of his local patients had many cavities.  Nor can my lack of cavities be attributed to good genes as attested by the cavities in my wisdom teeth.”

Comment 3

Dr Hardy Limeback: How Does Fluoride Become a Problem?

“I can write books on this. In fact, I co-authored this book( Download this book for FREE). Even fluoride in drinking water at 0.7 ppm will cause problems (dental fluorosis) if babies are fed infant formula made with fluoridated tap water. 1.5 ppm fluoride is the max around the world (except the US, where the EPA stubbornly is holding on to the higher Maximum Contaminant Level Goal (MCLG)). The EPA has been in court for over 6 years defending their excessively high level. We know even moderate increased consumption of fluoride from tap water during pregnancy, in athletes, in construction workers in hot climates, and in kidney patients who can’t filter the fluoride out, are overdosing on fluoride.”

KYH2O Response | Agree with Reservations 

Our page on Fluoride states the following: The EPA has set a primary (primary drinking water standard) maximum contaminant level for fluoride of 4 mg/L and a secondary (secondary drinking water standard) maximum contaminant level of 2.0 mg/L. Canada, Hong Kong, and the WHO (World Health Organization) have a standard of 1.5 mg/L.

Comment 4

Dr. Hardy Limeback: Health Effects

“ANY fluoride in drinking water above low levels (<0.3 mg/L) that occurs naturally in lakes and aquifers has ill-health side effects, not just >4 mg/L. Areas with naturally high fluoride levels in the water >4 mg/L) are known as endemic fluorosis areas where residents have major health effects, not just dental fluorosis.”

KYH2O Response: Agree with Additional Context

We searched for a reference to the limit of 0.3 mg/L. We found a reference with a limit of 0.6 mg/L on the website that stated the following:  “Fluoride is used to prevent tooth decay in people whose drinking water contains low levels of fluoride (less than 0.6 parts per million) and You should not use fluoride if the level of fluoride in your drinking water is greater than 0.6 parts per million (ppm).”

We did find this Table (See Table 2 from Source)

Fluoride Conc. In Drinking Water < 0.3 mg/L 0.3–0.6 mg/L > 0.6 mg/L
0 to < 6 months None None None
6 months to < 3 years 0.25 mg None None
3 to < 6 years 0.5 mg 0.25 mg None
6–16 years 1 mg 0.5 mg None

Note: In 1987, the reference dose suggested by USEPA is 0.06 mg fluoride/kg/ day, which is the estimate of daily exposure that is likely to be without any appreciable risk of deleterious effects (any degrees of dental fluorosis) during a lifetime.

Therefore, it appears the reference limit of 0.3 mg/L comes from a dosing monograph for fluoride supplements that is a function of drinking water fluoride concentration and age. More reason to get your drinking water Tested.

Comment 5

Dr. Hardy Limeback: Mottled Teeth

“The symptoms for fluoride in the water include: Mottled or discolored teeth. By that time it’s too late. The subject has been poisoned.”

KYH2O Response | Agree with Minor Reservations 

Tooth discoloration may occur for a number of reasons: dental trauma, certain beverages, poor oral hygiene (cavity), drug abuse, tobacco use, certain foods, drinks, some medications, and fluoride. We do disagree with the word choice “poisoned”, but that is a symptom for the problem and there are degrees to this problem.  In 1942, H.T. Dean developed an index to describe and diagnose enamel fluorosis.  At that time, it was assumed the optimal level of fluoride in the drinking water was equivalent to 1 mg/L. The Dean Index has 6 categories:

Normal (0) - The enamel represents the usual translucent semi-vitriform type of structure. The surface is smooth, glossy, and usually of a pale creamy-white color.

Questionable (0.5) The enamel has slight aberrations from the translucency of normal enamel, ranging from a few white flecks to occasional white spots. This classification is utilized in those instances where a definite diagnosis of the mildest form of fluorosis is not warranted but neither is a classification of ‘normal’ justified.

Very Mild (1) There are small, opaque, paper-white areas scattered irregularly over the tooth but not involving as much as 25% of the tooth surface. Frequently included in this classification are teeth showing no more than about 1–2 mm of white opacity at the tip of the cusps of the bicuspids or second molars.

Mild (2) The white opaque areas in the enamel of the teeth are more extensive but do not involve as much as 50% of the tooth.

Moderate (3) All enamel surfaces of the teeth are affected, and the surfaces subject to attrition show wear. Brown stain is frequently a disfiguring feature.

Severe (4) Includes teeth formerly classified as ‘moderately severe and severe.’ All enamel surfaces are affected and hypoplasia (incomplete development) is so marked that the general form of the tooth may be affected. The major diagnostic sign of this classification is discrete or confluent pitting. Brown stains are widespread and teeth often present a corroded-like appearance. (Source)

The quickest way to know if you may have a fluoride problem with your drinking water is to Get Tested

Comment 6

Dr. Hardy Limeback: Limits

“Getting back to the limit of 0.7 ppm.”

KYH2O Response  | Agree

When reviewing the CDC website, we found that fluoridated water community systems should “adjust fluoride to approximately 0.7 milligrams per Liter (mg/L).” Because in some rare locations fluoride is naturally present in water at much higher levels, the EPA established a Maximum Contaminant Level (MCL) for fluoride of 4.0 mg/L (parts per million). What is not clear is who or what agency set this limit of 0.7 mg/L.  The CDC (Centers for Disease Control) website suggested it was the American Water Works Association (AWWA)  and  NSF (formerly the National Sanitation Foundation)

When we search for the source of the 0.7 mg/L guideline, we found this:

According to the American Dental Association (Source “Fighting cavities with fluoride”)

“The amount of fluoride in water should be at 0.7 mg/L (0.7 ppm) to decrease the risks of dental fluorosis while having the benefits of fluoride to prevent cavities. Until they reach 8 years of age, children can be at risk of fluorosis if high levels of fluoride find its way into the child’s body.”

But when we searched the ADA website we only found this reference: View PDF.

To complete the circle

It appears the US Food and Drug Administration (FDA) has set an additive limit. “U.S. Food and Drug Administration issued its final rule for added fluoride levels in bottled water titled Beverages: Bottled Water. This final rule amends the allowable level for fluoride in domestically packaged and imported bottled water to which fluoride is added to 0.7 milligrams per liter (mg/L). The proposed rule was published in April 2019.”  (Source)   

Therefore the 0.7 mg/L limit is not a drinking water standard, but a standard that would apply to additives.  This changed the original permissible limit from 0.8 to 1.7 mg/L, to a new limit of 0.7 mg/L.   So there is a clear disconnect between the drinking water standards and the process water or additive standards – Why? My guess is cost. There are some community water supply systems with naturally high levels of fluoride for which the cost of treatment would not be financially sustainable.  The main problem is that the public does not get to know how the “CAKE was Made – Just are TOLD that to Eat It is ok” and the public may not be looking very hard at the public water suppliers Annual Consumer Confidence Report or the public is using a private water source that is not really tested or regulated. .    

We want to thank the website visitor for taking time to provide us with more information about fluoride in drinking water. These types of fact-based discussions are critical for an individual to make a determination of what is best for themselves and their family. The KnowYourH2O Team supports fact-based information, getting your water tested, implementing the level of treatment the user believes is best for their families and applications, and recommends that the user maintain and monitor their system under the understanding that “We ALL Live Downstream.”

Our Recommendations

Get Tested - Water Testing for Fluoride

Level 2 Testing (Do it Yourself):

16 in 1 Drinking Water Test Kit Strips, 100 cnt.

Safe Home® CITY WATER Test Kit

Level 3 Testing (Informational Water Test):

Well Water Basic - includes a test for fluoride and general water quality. 

City Water Basic - includes a fluoride test and a test for other parameters of concern including chlorine and disinfection by-products.

Get Treatment - Water Treatment Systems (Point of Use) – Target Fluoride

City Water

Hydroviv is a new Point-of-Use Drinking Water Treatment partner with a different approach, i.e., customized Point-of-Use water Treatment systems for your tap, shower head, ice maker, and refrigerator.

Well Water

Crystal Quest has POU (point-of-use under-the-counter) filters with a focus on fluoride removal that provide quality filtered water at or near any water line. With changeable cartridges, these filters are easy to use, maintain, and long-lasting. With a variety of models available, we are guaranteed to have the perfect filter to suit your needs.

Crystal Quest has a high-capacity Inline filter with a focus on fluoride removal (4 to 6 gpm) that provides quality filtered water at or near any water line. With changeable cartridges, these filters are easy to use, maintain, and long-lasting. With a variety of models available, we are guaranteed to have the perfect filter to suit your needs.

Crystal Quest – Whole-House Filtration Application for Fluoride Reduction - Our Fluoride Removal Whole-House Water Filters utilize a high-capacity Eagle Activated-Charcoal Fluoride-Removal Medium - Calcium Granular Activated Carbon (GAC) is a unique carbonaceous adsorbent manufactured from the treatment and carbonization of selected grades of animal bone and is used for liquid-phase filtration to remove organic and inorganic species such as organic compounds and many heavy metals.

KnowYourH2O Final Notes

We appreciated the comments regarding our website.  We hope this blog post with the Q and A and our responses added additional context and information to permit the citizen to make an educated and informed decision based on facts. 

On a personal note – In the area where I grew-up (an old mining town) we have a public water supply system that did add a fluoride supplement to the drinking water and the natural or background level of fluoride in the drinking water was < 0.5 mg/L. Growing up I did use a rinse that contained fluoride or use a toothpaste with added fluoride and received fluoride treatment from my dentist.   Currently, I brush my teeth using a homemade baking soda and dilute peroxide rinse with an over-the-counter mouthwash, and I store my toothbrush in a stronger, more astringent mouthwash. 

At this point, a bigger concern from me is the exposure to PFOS and other Forever Chemicals that are contained in many consumer goods. 

In closing, the individual and the community should make the determination if the drinking water should have fluoride addition, not a local authority or a government agency or health department. This freedom comes with a price, i.e., responsibility and duty.  If you do not want to be a “sheep,” please be responsible for your efforts to promote a healthy home, healthy family, and a healthy community. This means you will need to check your drinking water quality, install and maintain the necessary pretreatment or treatment systems, monitor the performance of these systems, annually check your untreated and treated drinking water quality, get educated, and assist in informing the public (Like and Share).