in analytical chemical reactions and from laboratory experiments with animals. Furthermore, the reduction in dental caries attack rates produced by artificial fluoridation programs in Grand Rapids, Evanston, Newburgh, and so forth, demonstrates the physiological identity of fluoride added at the waterworks to that dissolved into waters from soils and rocks.

TOXICITY IS NOT QUALITATIVE

Misunderstandings have arisen in discussions of fluoridation of water owing to the fact that very large amounts of fluoride are toxic. When sodium fluoride is employed as a rat or cockroach poison, the dry and nearly pure compound is used. The aim is to produce acute lethal fluoride intoxciation in the vermin, a circumstance which would require an impossibly large intake of fluoridated water. In water fluoridation the fluoride compound is highly diluted to one part of fluoride in a million parts of water.

It is not possible to state categorically that any substance is a poison without defining the amounts of the substance or the conditions of its administration. And this applies to fluoride also. Numerous substances, including many required by the body, are toxic when taken in large amounts. Dr. Doty has already referred to vitamin A. For example, the essential vitamin D produces toxic effects in human when given in careless overdosages. One further example, air contains 21 percent oxygen and we breathe air in order to obtain oxygen for essential body needs. If an animal breathes pure oxygen, particularly under pressure, it will suffer ill effects and if the experiment is continued long enough the animal will surely die. Under these conditions oxygen is a poison.

Mr. HALE. Thank you, Dr. Armstrong. Are there any questions? The committee is indebted to you, sir.

Dr. ARMSTRONG. Thank you.

STATEMENT OF DR. FRANCIS F. HEYROTH, M. D., PH. D., ASSOCIATE PROFESSOR OF INDUSTRIAL TOXICOLOGY AND ASSISTANT DIRECTOR OF THE KETTERING LABORATORY, DEPARTMENT OF PREVENTIVE MEDICINE AND INDUSTRIAL HEALTH, COLLEGE OF MEDICINE, UNIVERSITY OF CINCINNATI, CINCINNATI, OHIO Mr. HALE. Dr. Heyroth, the committee will hear you.

Dr. HEYROTH. Mr. Chairman and gentlemen of the committee. My name is Francis F. Heyroth. I hold the degrees of M. D. and Ph. D., both from the University of Cincinnati. I am associate professor of industrial toxicology and assistant director of the Kettering laboratory in the department of preventive medicine and industrial health, college of medicine, University of Cincinnati. I also serve as associate professor of biological chemistry in the college of medicine and as a member of the Cincinnati Board of Health.

The Kettering laboratory studies the dangers to workmen and consumers that attend the manufacture and use of potentially toxic substances. Its work on fluorides began more than 20 years ago shortly after fluorosis became recognized in Denmark as an occupational abnormality, occurring among men engaged in grinding a mineral known as cryolite or sodium aluminum fluoride. In the course of

routine X-ray examinations of these Danish workmen, an increase in the density of the shadows of the bones of many of them was noted. This was of a type not hitherto encountered. It was subsequently established that it was an effect associated with the accumulation of fluoride in the bones.

Our laboratory has made many observations on experimental animals and on human volunteers in the effort to learn the fact of known amounts of fluorides when ingested daily over prolonged periods. We sought to find what part of the dose is excreted in the urine and how much is retained in the body, where it is stored in the bones. Our goal was to determine the maximum amount that a workman might absorb daily into his tissues without storing too much in his bones.

I happen to be a member of the Cincinnati Board of Health. When the Cincinnati Board of Health was asked for an opinion on the advisability of fluoridation, I reviewed the data of our laboratory and the extensive published literature on the toxicity of fluorides at the request of my fellow members. My report to the board was recently reprinted by the British Ministry of Health as an appendix to the report of its mission to investigate fluoridation in North America.

THE NATURE OF H. R. 2341

This bill represents an attempt to initiate Federal legislation on the fluoridation of public water supplies now in progress in hundreds of cities and towns as a public-health measure for lessening the prevalence of dental decay. The House Select Committee to Investigate the Use of Chemicals in Foods, the Delaney committee, devoted 7 days in 1952 to hearings on fluoridation and issued a report on this subject dated July 10, 1952. The opening two sentences of the final paragraph of its conclusions and recommendations read as follows:

The advisability of fluoridating the public water supply of the Nation is essentially a local problem, to be determined for itself by each community. Your committee is not recommending that Federal legislation be enacted in this field.

About 6 months later, H. R. 2341 was introduced and referred to your committee. It reflects the unwillingness of those opposed to fluoridation to abide by the locally arrived at decisions of the many communities that have adopted this public health measure and seeks to negate their decisions by Federal edict. Those promoting this bill may be doing so in the belief that the United States Public Health Sesrvice is seeking to promote the universal fluoridation of the water supplies of the Nation. If so, they are incorrect. Fluoridation is recommended only for those communities whose water supplies contain from natural sources less than the amount that has been shown to be optimal for dental health. In most areas this is 1 part per million; in a few, it is somewhat less. Where grossly excessive amounts occur naturally the Public Health Service has advised and insisted on the installation of equipment for the removal of the excess.

The clause in H. R. 2341 that states that "no agency of any State or of any municipality or other political subdivision of the State shall treat any public water supply with any fluoride compound" seems an attempt to exercise powers that are reserved to the States. If the bill becomes law some of its provisions might create difficulties where

fluoridation is in progress. An interstate common carrier might be enjoined from obtaining its supply of drinking water from a city where the water is fluoridated.

Any justification that the bill may have depends upon the validity of the premise in its opening clause, "To protect the public health from the dangers of the fluorination of water." The evidence that this is false and that fluoridation is safe has been brought together in three publications by me which constitute the essence of my statement and which I have submitted to the clerk for distribution to the committee. And, I might interpolate, in preparing this report I felt deeply the sense of responsibility which had been placed upon me by my official position.

1. My report to the Cincinnati Board of Health, dated January 26, 1951.

2. Reprints of an article "Toxicological Evidence for the Safety of the Fluoridation of Public Water Supplies," published in the American Journal of Public Health, 42, 1568-1952.

3. Reprints of a letter to the editor of Industrial and Engineering Chemistry, 45, 2369-1953-entitled "Effectiveness and Safety of Fluoridation of Public Water Supplies."

These may be summarized briefly as follows: The evidence derives from four sources, (1) animal and (2) human experimentation, (3) epidemiological studies of the health of residents of communities whose water bears excessive amounts of fluorides, and (4) the results of the medical examination of workmen exposed to fluorides in industry.

Values for the maximum daily intake of fluoride that may be tolerated by animals of various species have been found from the results of the very great number of experiments performed since 1890. Expressed in milligrams of fluoride per kilogram of body weight, these values are: dairy cattle, 1 to 3; swine, 5 to 12; rats, 10 to 20; guinea pigs, 12 to 20; chickens, 35 to 70. I shall mention only one experiment done in our own laboratory. Each of two 11-months-old littermate dogs was given daily 65 milligrams of fluoride; the third littermate was given none. One dog was given its fluoride as the sodium salt, while the other was given it as cryolite. The administration was continued for 5 years and 5 months. It was stopped because of the death of the dog that had been given none. During life, no osseous changes could be detected roentgenographically in any of the dogs. Storage occurred in the bones, for the ash of those of the dog given sodium fluoride contained 10 times the amount of fluoride found in those of the dog used as control, and given none. No noteworthy histopathologic changes were found in the organs of the fluoride-fed dogs.

The painstaking human balance studies of our laboratory referred to in my introduction offer direct evidence as to the manner in which men and women disposed of the fluoride they took. One of our volunteers took daily 12 milligrams of fluoride as tablets of sodium fluoride over a period of 130 weeks. This daily dose represents the amount present in 12 quarts of fluoridated water with 1 part per million. Careful medical examination made at the end of this period revealed no evidence of any harm. Other persons took lesser doses. In none of our volunteers did any radiographic change occur in the density of their bones, even though one of them had taken 21 grams of sodium fluoride over a little more than 2 years.

The objection that 2 years is too short a period to permit conclusions to be drawn does not apply to the third line of evidence the study of the health of persons who have lived to advanced age where the water supply contains from natural sources more than 1 part per million. Hodges found no evidence of skeletal fluorosis in X-rays of 31 persons who had lived for 18 to 68 years at Bureau, Ill., where the water has 2.5 parts per million, or in those of 86 residents of Kempton, Ill., where the content has varied between 1.3 and 3 parts per million. We have had examined the X-rays of 50 persons living in Lake Preston, S. D., where the water has 6 parts per million. One radiologist found minimal changes in two of these persons, but another radiologist could not agree that the changes were real, or beyond the normal range of variation. A radiologic survey of 114 persons who had lived for at least 15 years at Bartlett, Tex., where the water has 8 parts per million revealed minimal evidence of an increase in density of the bones of 12 percent of those examined, but in no case was there any deformity or interference with skeletal function. Medical examinations, which included urinalyses and blood counts, gave no evidence that the residents of Bartlett were any less healthy than were those of nearby Cameron, where the water contained only 0.3 parts per million. We have found that the average daily intake of fluoride by a 63-year-old man and his 57-year-old wife, long resident in Bartlett, amounted to 15.3 milligrams, while their urinary concentration approximated very closely that of the drinking water, 8 parts per million.

The examination of men long exposed in industry to a fluoride-contaminated atmosphere offers further evidence. The average urinary concentration of the previously mentioned Danish workers amounted to 16 milligrams per liter or twice that of the 2 residents of Bartlett studied by us. Medical studies or men in industries of the United States have been made to establish the safe level of the industrial environment. On comparing their X-ray findings and urinary output with those of persons who acquire their fluoride from water, it is found that an increase in bone density may be detected at a daily intake of about that that corresponds to the use of drinking water with 5 or more parts per million.

All 4 lines of evidence lead to the conclusion that fluoridation of water to 1 part per million has an ample margin of safety.

On behalf of the American Public Health Association, which in 1950 adopted a resolution recommending fluoridation, I wish to thank the committee for affording me the opportunity of appearing before it. In other words, no evidence could be found of any harm by examination of the bones, so long as the drinking water did not contain 5 parts at least, and very minimum if any change occurred when it contains 4, 5 or more.

Mr. HALE. Thank you, Dr. Heyroth. Are there any questions, gentlemen?

Mr. HESELTON. Mr. Chairman.

Mr. HALE. Mr. Heselton.

Mr. HESELTON, Doctor, you have testified, and others have, that approximately 1 part per million is the safety factor that you observe. Would you explain why it is that during hot weather that amount is reduced?

Dr. HEYROTH. Yes. The water intake is believed to be a little higher during hot weather. There are a few cities that change the amount

added for fluoridation with the season. Charlotte, N. C., is one, I think. They drop it to about eight-tenths of a part per million in warm weather and increase it to 1.2 parts per million in cold weather, merely because of the variation of the amount of water that one would drink.

Now, what occurs insofar as the intake of any particular day is concerned, is of rather little importance. It is how much is taken in over the months and over the entire year that counts.

So, one endeavors to make it come out at an average income, intake per day over a year of 1 part per million. To do that in summer, you may have a little less in the water, because you drink more water. Mr. HESELTON. Then it is not universally done?

Dr. HEYROTH. Not universally done; no. That is up to the regulations of the health department or the water-works board, or the council of the local community.

Mr. ROGERS. Mr. Chairman.
Mr. HALE. Mr. Rogers.

Mr. ROGERS. Doctor, I believe that you agree with the statement made here to the committee with the gentlemen who commented on this, and in which they stated that the water supply of the Nation is essentially a local problem and the passage of this would be encroachment on States' rights. Is that not true?

Dr. HEYROTH. That evidently is the thinking on it.

Mr. ROGERS. Do you not agree with that?

Dr. HEYROTH. Certainly.

Mr. ROGERS. Well, I do, too.
Thank you very much.

Mr. HARRIS. Mr. Chairman.

Mr. HALE. Mr. Harris.

Mr. HARRIS. Doctor, you explained that the Cincinnati Board of Health asked you for an opinion on the value of fluoridation. What was the action of the city of Cincinnati with reference to fluoridation? Dr. HEYROTH. I happened to be a member, as I said, of the Board of Health.

Mr. HARRIS. Yes.

Dr. HEYROTH. I gave the report to which I referred to my fellow members on the board, and you have a copy of it.

Mr. HARRIS. Yes.

Dr. HEYROTH. The board approved it unanimously. It went in to, in due course, to the city council. They approved it unanimously. At abount that time a radio commentator began arousing fears on the part of the Cincinnati public. He appeared before the council. They conducted a public hearing, at the conclusion of which they revoted on the question.

Mr. HARRIS. You mean the council revoted?

Dr. HEYROTH. The council revoted. This time, again, they were in favor of it by 8 to 1.

Mr. HARRIS. What?

Dr. HEYROTH. By 8 to 1, in favor of it.

Mr. HARRIS. 8 to 1 in favor of it?

Dr. HEYROTH. In favor of it; yes, sir. But, this was passed not as emergency legislation and under the city laws they have

Mr. HARRIS. Now, wait a minute. I misunderstood you. I thought you said the first time that they approved it.