Fluoride Action Network

Sodium fluoride: FAN Comments on EPA’s Assessment for Wood Treatment Products

December 10th, 2007

December 10, 2007

SUBMISSION to US EPA Office of Pesticides

from Fluoride Action Network
82 Judson Street, Canton, New York 13617

Re:  Comments on Sodium Fluoride Risk Assessment:


There are safer, saner and less toxic alternatives to the use of sodium fluoride in treating wood utility poles and railroad ties.  Throughout Europe most railroad ties are made with cement.  Utility poles can either be made with cement or metal.  We urge EPA to phase-out the use of sodium fluoride wood treatments because available alternatives do not pose unnecessary risks to human health or the environment.


•  EPA must title its Re-registration Eligibility Decision document clearly.  For example:   “Sodium fluoride Use for Wood treatment” and not just “Sodium fluoride.”


To assess the risks of these wood treatment products, the public needs to know what other unidentified biologically active substances/chemicals are in the sodium fluoride wood treatment products.  Without this information, a complete risk assessment is not scientifically tenable.



EPA has invested a lot of credence in the Sprando and Collins rat studies.  Their studies found negligible effects of sodium fluoride on developmental toxicity and male reproduction at levels up to 250 ppm NaF.  One of the findings that raises serious questions about these studies is the notably low incidence and severity of dental fluorisis in their treated animals.  Even in the highest dosed animals (250 ppm NaF) the only dental fluorosis that was observed, according to the authors, was mild in nature.  This is in stark contrast to most other studies which typically find severe changes to tooth enamel at concentrations ?100 ppm.  (Den Besten et al. 1984,1985; NTP 1990).   In the NTP study, for instance, at 79 ppm, animals exhibited severe fluorosis of the enamel.  Thus, the abnormally mild nature of the fluorosis observed in the Sprando and Collins studies suggests that the level of bio-available fluoride in these studies may be less than the authors assumed.


•  Chronic Effects (page 28) needs to be updated to include the following effects. The NAS report of 2006 stated that the the Maximum Contaminant Level Goal of 4 parts per million was not protective for these effects:

• Bone Fracture

• Stage 2 Skeletal Fluorosis characterized by chronic joint pain, arthritic symptoms, slight calcification of ligaments, and osteosclerosis of the cancellous bones.


TOXICITY TO TERRESTRIAL ANIMALS:  EPA failed to include fluoride’s effect as a teratogen. According to Gof and Neff:

“The effects of sodium fluoride on the development of frog embryos were studied under conditions described by the Frog Embryo Teratogenesis Assay-Xenopus (FETAX), a screening assay for teratogens. The most prominent malformations caused by sodium fluoride are reduction in the head-tail lengths and dysfunction of the neuromuscular system of the tadpoles. The values for LC50, EC50, and minimal concentration to inhibit growth (MCIG) of sodium fluoride met the limits established for a teratogen in frog embryos, showing that sodium fluoride is a direct acting teratogen on developing embryos. Since FETAX has a high degree of success in identifying mammalian teratogens, the observed teratogenic action of sodium fluoride on frog embryos would indicate a strong possibility that sodium fluoride may also act directly on developing mammalian fetuses to cause malformation.”


•  FLUORIDE AS A CARCINOGEN:  EPA  dismissed the role of fluoride as a carcinogen by citing the NAS 2006 report’s conclusion that “evidence on the potential of fluoride to initiate or promote cancers, particularly of the bone, is tentative and mixed.”    However, AFTER the NAS report was published, Bassin et al. published findings of a five-fold increased risk of developing osteosarcoma in teenage boys who drank fluoridated water at ages 6, 7, and 8. Bassin’s approach of investigating the risk of osteosarcoma as a function of the year in which the child is exposed is a breakthrough in understanding how fluoride may cause bone cancer.  We urge EPA to take this biologically plausible finding seriously.

•  WORKER PROTECTION:  In EPA’s approval of any  NaF wood treatment product it must insure that workers are protected by requiring

• An assessment of the worker for prior fluoride exposure via blood and urine tests prior to their employment.

•  Women of child bearing age should not be allowed to work with these products.  It is known that NaF can cross the placenta and accumulate in the brain of human fetuses.  (See Du L. (1992). The effect of fluorine on the developing human brain. Chinese Journal of Pathology 21(4):218-20.

• During employment: Regular blood and urine samples need to be taken of workers at a minimum of every 4 months throughout their employment

• Indoor air should be tested for fluoride levels.

• Workers should be examined for Stage 2 Skeletal fluorosis which is characterized by chronic joint pain, arthritic symptoms, slight calcification of ligaments, and osteosclerosis of the cancellous bones.

According to Gupta et al.:

“Skeletal fluorosis in India and China has been reported to occur when the fluoride concentration in water exceeds 1 ppm, and has been found to occur in communities with only 0.7 ppm (Bo et al.; Choubisa et al.). The Chinese government now considers any water supply containing over 1 ppm fluoride a risk for skeletal fluorosis(Bo et al.). This is in contrast to the USA, were the Maximum contaminant limit is established by the US Environmental Protection Agency as 4ppm. This difference in limits of fluoride levels may be explained by the lower tendency to develop fluorosis in this population. Many case reports in the USA have documented skeletal fluorosis among people with kidney diseases at water fluoride levels as low as 1.7 ppm, and among heavy tea drinkers at water fluoride levels as low as 2.2–3.5 ppm.”


DISPOSAL of the Treated Wood:

EPA must require that disposal of these treated wood products are not recycled into inappropriate uses such as children’s playgrounds, pens for agricultural animals, backyard gardens, etc.  EPA must also ban the outdoor burning of this treated wood.

According to DeBey et al., in 2005, a broken package of Cop-R-Plastic (containing130,000.0 mg/kg fluoride) was unintentionally left in a pasture by workers treating utility poles.  The findings indicated that the sodium fluoride caused renal tubular necrosis leading to renal failure.  “Fourteen cattle (11 adult cows and 3 calves) died or became moribund and were euthanatized over a 4-week period.  Clinical signs included depression, anorexia, ataxia, excessive salivation, watery diarrhea, and recumbency … Serum chemistry revealed hyponatremia, hypokalemia, hypochloridemia, and hypocalcemia in 2 of 2 cows tested and azotemia in 3 of 3 cows tested (Table 1). “


•   IQ:
Wang et al.  (2007).  Arsenic and Fluoride Exposure in Drinking Water: Children’s IQ and Growth in Shanyin County, Shanxi Province, China.  Environ Health Perspect. 2007 Apr;115(4):643-647.  January 9.

•  Learning, memory, motor coordination, and sexual behavior:
Bera et al.  (2007).  Neurofunctional effects of developmental sodium fluoride exposure in rats.  Eur Rev Med Pharmacol Sci. 11(4):211-24.  July-August.

•  Learning and memory:
Chioca  et al.  (2007).  Subchronic fluoride intake induces impairment in habituation and active avoidance tasks in rats.  Eur J Pharmacol. 2007 Oct 25 [Epub ahead of print]

•  Testes:
Oncü et al.  (2007).  Effect of long-term fluoride exposure on lipid peroxidation and histology of testes in first- and second-generation rats.  Biol Trace Elem Res.118(3):260-8.  September.

•  Testes:
Jiang et al.  (2007).  [Effect of fluoride on expression of telomerase reverse transcriptase expression and proliferating cell nuclear antigen in germ cells of rats’ testes].  Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi. 25(2):96-9.  February.

•  Mouse Sperm:
Dvofiáková-Hortová et al.  (2007).  The influence of fluorides on mouse sperm capacitation.  Anim Reprod Sci. Aug 6 [Epub ahead of print]

•  Neurotoxicity:
Zhang et al.  (2007).  Effects of fluoride on the expression of NCAM, oxidative stress, and apoptosis in primary cultured hippocampal neurons.  Toxicology 236(3):208-216.  July 17. Epub 2007 Apr 24.

•  Cytotoxicity:
Matsui  et al.  (2007).  Some characteristics of fluoride-induced cell death in rat thymocytes: Cytotoxicity of sodium fluoride.  Toxicol In Vitro. April 27.

•  Bone:
Hallanger Johnson et al.  (2007).  Fluoride-related bone disease associated with habitual tea consumption.  Mayo Clin Proc. 82(6):719-24.  June.

•  Bone:  Osteoclastogenesis:
Yan et al.  (2007).  Genetic background influences fluoride’s effects on osteoclastogenesis.  Bone 41(6):1036-44. December.

•  Oxidative Stress:
Bouaziz et al.  (2007).  Oxidative stress induced by fluoride in adult mice and their suckling pups.  Experimental and Toxicologic Pathology, Volume 58, Issue 5, Pages 339-349. April 26.

•  Oxidative Stress:
Jin et al.  (2007).  Fluoride-induced oxidative stress of osteoblasts and protective effects of baicalein against fluoride toxicity.  Biol Trace Elem Res. 116(1):81-90.  April.


CHINESE STUDIES WE HAVE TRANSLATED:  Studies available in Chinese version and in English translation at


Li J, Yao L, Shao Q-L. (2004). Effects of high-fluoride on neonatal neurobehavioural development. Chinese Journal of Endemiology 23:464-465.  [Chinese version | English translation]

Guo Z, et al. (2001). Study on neurobehavioral function of workers occupationally exposed to fluoride. Industrial Health and Occupational Disease 27:346-348.  [Chinese version | English translation]

Yu Y, et al. (1996). Changes in neurotransmitters and their receptors in human foetal brain from an endemic fluorosis area. Chinese Journal of Endemiology 15:257-259.  [Chinese version | English translation]

Du L. (1992). The effect of fluorine on the developing human brain. Chinese Journal of Pathology 21(4):218-20.  [Chinese version | English translation]

Han H, et al. (1989). The effects of fluorine on human fetus. Chinese Journal of Control of Endemic Diseases 4:136-138.  [Chinese version | English translation]

Sun ZR, et al. (2000). Effects of high fluoride drinking water on the cerebral functions of mice. Chinese Journal of Epidemiology 19: 262-263. [Chinese version | English translation]

Zhang Z, et al. (1999). [Effect of fluoride exposure on synaptic structure of brain areas related to learning-memory in mice] [Article in Chinese]. Journal of Hygiene Research 28(4):210-2. [Chinese version | English translation]

Wu N, et al. (1995). Research on the abnormal behavior of rats exposed to fluoride. Chinese Journal of Control of Endemic Diseases 14(5):271. [Chinese version | English translation]


FLUORIDE/IQ:  Studies available in Chinese version and in English translation at

Seraj B, et al. (2006). [Effect of high fluoride concentration in drinking water on children’s intelligence]. Journal of Dental Medicine 19(2):80-86. [Persian version | English translation]

Wang S, et al. (2005). Effects of coal burning related endemic fluorosis on body development and intelligence levels of children. Journal of Applied Clinical Pediatrics 20(9): 897-898. [Chinese version | English translation]

Li Y, et al. (2003). The effects of endemic fluoride poisoning on the intellectual development of children in Baotou. Chinese Journal of Public Health Management 19(4):337-338. [Chinese version | English translation]

Hong F, et al. (2001). A study of fluorine effects on children’s intelligence development under different environments. Chinese Primary Health Care 15: 56-57. [Chinese version | English translation]

Wang G, et al. (1996). Research on intelligence quotient of 4-7 year-old children in a district with a high level of fluoride. Endemic Diseases Bulletin 11:60-62. [Chinese version | English translation]

Li Y, et al. (1994). Effect of excessive fluoride intake on mental work capacity of children and a preliminary study of its mechanism. Journal of West China University of Medical Sciences 25(2):188-91. [Chinese version | English translation]

Yang Y, et al. (1994). Effects of high iodine and high fluorine on children’s intelligence and the metabolism of iodine and fluorine. Chinese Journal of Pathology 15(5):296-8. [Chinese version | English translation]

Guo XC, et al. (1991). A preliminary exploration of IQ of 7-13 year old pupils in a fluorosis area with contamination from burning coal. Chinese Journal of Endemiology 10:98-100. [Chinese version | English translation]

Chen YX, et al. (1991). Research on the intellectual development of children in high fluoride areas. Chinese Journal of Control of Endemic Diseases. 6(supplement):99-100. [Chinese version | English translation]

Qin LS, Cui SY. (1990). The influence of drinking water fluoride on pupils IQ, as measured by Rui Wen’s standards. Chinese Journal of the Control of Endemic Diseases 5:203-204. [Chinese version | English translation]

Ren Da-Li. (1989). An investigation of intelligence development of children aged 8-14 years in high-fluoride and low-iodine areas. Chinese Journal of Control of Endemic Diseases 4:251. [Chinese version | English translation]

Hu YS, Yu XZ, Ding RQ. (1989). Investigation of students’ intelligence quotient aged 6-14 years old in the endemic fluorosis area. Collection of papers and abstracts of 4th China Fluoride Research Association. Quiyang, China, 6:73. [Chinese version | English translation]


OTHER TRANSLATIONS (Non-NEURO):  Studies available in Chinese version and in English translation at

Shi J, Dai G, Zhang Z. (1995). Relationship between bone fluoride content, pathological change in bone of aborted fetuses and maternal fluoride level. Chinese Journal of Preventive Medicine 29(2):103-5. [English translation]

Chen, et al. (1990). A study of the effects of fluoride on foetal tissue. Chinese Journal of Endemiology 9:345-346. [Chinese version | English translation]



Bassin EB, Wypij D, Davis RB, Mittleman MA.  (2006).  Age-specific fluoride exposure in drinking water and osteosarcoma (United States).  Cancer Causes Control. 17(4):421-8.  May.

Bo Z, Mei H, Yongsheng Z, Xueyu L, Xuelin Z, Jun D.  (2003).  Distribution and risk assessment of fluoride in drinking water in the west plain region of Jilin province, China.  Environ  Geochem Health 25:421–31.

Choubisa SL, Choubisa L, Choubisa DK. (2001). Endemic fluorosis in Rajasthan. Indian J Environ Health 43:177–89.

Collins TFX, Sprando RL, Black TN, Shackelford ME,  Olejnik N, Ames MJ, Rrie JI, Ruggles DI.  (August 2001).  Developmental toxicity of sodium fluoride measured during multiple generations.  Food and Chemical Toxicology, 39(8), 867-876

Collins TFX, Sprando RL, Black TN, Shackelford ME, Black TN, Ames MJ, Welsh JJ, Balmer MF, Olejnik N, Ruggles DI. (1995). Developmental toxicity of sodium fluoride in rats. Food ChemToxicol. 33(11): 951-60. November.

Collins TFX, Sprando RL, Black TN, Shackelford ME, Bryant MA, Olejnik N, Ames MJ, Rorie JI,  Ruggles DI. (June 2001).  Multigenerational evaluation of sodium fluoride in rats. Food and Chemical Toxicology, Volume 39, Issue 6, Pages 601-613.

DeBey BM, Jacob B, Oehme FW, Imerman P.  (2007).  Sodium fluoride/copper naphthenate toxicosis in cattle.  Journal of Veterinary Diagnostic Investigation 19(3):305-8.  May.

DenBesten PK, Crenshaw MA. (1984). The effects of chronic high fluoride levels on forming  enamel in the rat. Archives of Oral Biology 29: 675-9.

Denbesten PK et al. (1985). Changes in the fluoride-induced modulation of maturation stage ameloblasts of rats. Journal of Dental Research 64: 1365-70.

Goh EH and Neff AW. (2003).  Effects of fluoride on Xenopus embryo development.  Food Chem Toxicol. 41(11):1501-8.  November.

Gupta R, Kumar AN, Bandhu S, Gupta S.  (2007).  Skeletal fluorosis mimicking seronegative arthritis.  Scandinavian Journal of Rheumatology  36:2, 154 – 155 .

NAS (National Academy of Science).  (2006). Fluoride in Drinking Water: A Scientific Review of EPA’s Standards. The National Academies Press. United States.

NTP (National Toxicology Program),  (1990). Toxicology and Carcinogenesis Studies of Sodium Fluoride in F344/N Rats and B6C3f1 Mice. Technical report Series No. 393. NIH Publ. No 91-2848. National Institute of Environmental Health Sciences, Research Triangle Park, N.C.

Pushpalatha et al.  (2005).  Exposure to high fluoride concentration [4.5 ppm and 9.0 ppm] in drinking water will affect spermatogenesis and steroidogenesis in male albino rats.  Biometals 18(3):207-12.  June.

Sprando RL, Collins TFX, Black TN, Rorie J, Ames MJ, O’Donnell M. (1997). Testing the  potential of sodium fluoride to affect spermatogenesis in the rat. Food Chem Toxicol. 35(9): 881-90.  September.

Sprando RL, Collins TFX, Black TN, Olejnik N, Rorie J. (1998). Testing the potential of sodium fluoride to affect spermatogenesis: a morphometric study. Food Chem Toxicol. 36(12):1117-24.  December.

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Note: Documents released by EPA on October 10, 2007:

Sodium Fluoride Risk Assessment; Notice of Availability and Risk Reduction Options. This notice announces the availability of EPA’s risk assessment, and related documents for the pesticide Sodium Fluoride and opens a public comment period on these documents. Comments on the following documents are due by December 10.

Sodium Fluoride Preliminary Risk Assessment for the Reregistration Eligibility Decision (RED) Document . Sept. 30, 2007 (87 pages)

Revised Occupational and Residential Exposure Chapter for the Sodium Fluoride Reregistration Eligibility Decision (RED). Oct. 1, 2007 (12 pages)

Environmental Fate Science Chapter for the Sodium Fluoride Reregistration Eligibility Decision (RED) Document. Sept. 25, 2007 (8 pages)

Sodium Fluoride Toxicology Chapter for Issuance of the Reregistration Eligibility Decision (RED) Document. Sept. 30, 2007 (78 pages)

Product Chemistry Science Chapter For: Sodium Fluoride Reregistration Eligibility Decision (RED). Sept. 25, 2007 (2 pages)

Revised Ecological Hazard and Environmental Risk Assessment Science Chapter for the Sodium Fluoride Reregistration Eligibility Decision (RED). Sept. 25, 2007 (13 pages)

Sodium Fluoride – Incident Report Summary. Aug. 3, 2007 (11 pages)