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    "label": "Report, January 23, 1928",
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    "id": "75722279",
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    "title": "Report, January 23, 1928",
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        "Safety Light Collection",
        "Records Related to Radium Dial Painters"
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    "seq": 8,
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    "ocrText": "Comments upon and Criticisms of a Report to U.S. Radium\nCorp. by Dr. Cecil K. Drinker, dated June 3,1924,\nConcerning the Cause of Necrosis of the Jaw\namong Dial Painters.\nThis report is being submitted at the request of Dr. H.H. Barker, Vice President\nof the U. S. Radium Corp., as outlined in his letter to the writer, dated\nJan. 11, 1928.\nAll of my own experience and all of my reading of the literature lead\nme to believe that the magnitude of the physiological effect of radium, other\nthings being equal, is more or less closely proportional to the product of\nthe quantity of radium and the duration of the exposure -- the larger the\nquantity and the longer the time of exposure the more pronounced the effect.\nFurthermore, quantity and duration being fixed, distance of the radium from the\nperson greatly influences the effect -- naturally the farther removed, the less\nthe effect; the closer the approach, the more pronounced the effect. The\neffect of radium outside the body is due to so-called rays or radiations.\nThese are of 3 kinds, a,B and , each kind absolutely distinct and different\nfrom either of the others. The a rays are helium atoms which are wholly\nstopped by the glass walls of any tube in which the Ra is contained, if the\nglass is thicker than a sheet of writing paper. Therefore in exposure to\nexternal radium the a rays are to be left out of consideration.\nThe B rays are electrons -- particles of electricity -- which can pene-\ntrate thin glass with only partial absorption and can penetrate the skin and\ntissues to a slight extent. The rays are ether vibrations. These are of\nthe same general nature as radio broadcasting waves, visible light, and X-rays.\nBroadcasting waves are very long -- 200 to 500 meters. X-rays are very short,\ngamma rays are still shorter. The latter penetrate all kinds of material more\nor less readily; they are absorbed in passing through such material, being\nabsorbed or stopped more readily by screens of metallic lead then by other\nmaterial of equal thickness. The greater the thickness the greater the absorp-\ntion of the gamma rays. Only gamma rays can escape from radium screened with\n1/8 of an inch of sheet lead.\nIn brief, the physiological effect pr oduced by radium, external to the\nbody, depends upon,\n1. Quantity of radium\n2. Duration of exposure\n3. Distance from body\n4. Screening\nOther radioactive substances behave in large measure like radium in respedt to\nthe foregoing conditions.\nWhen radium is taken into the body, the effect produced will depend on\nthe quantity of radium, on the length of time the radium remains in the body,\nwhich in turn is largely governed by the speed of its elimination from the body.\n-2-\nThe factors of distance and screening do not come into consideration here as\nwhen the radium is external to the body. Gaseous radioactive substances, like\nradium emanation, when taken into the lungs with inhaled air, are rather quickly\neliminated.\nThere is no question that prolonged exposure to the radiation of a\nsufficiently large quantity of radium at close range and not heavily screened\nis capable of producing most marked physiological effects on human beings.\nSkillfully handled, such radiation has for 20 years or more been employed\ntherapeutically for the destruction of malignant growths, with resultant benefit\nto mankind. On the other hand, it seems well established that greater or less\nharm may result from incautious or prolonged exposure of the healthy body to\nmore or less strong radium radiation. Finger burns of those handling tubes of\nhighly concentrated radium are the commonest evidence in this direction.\nThere now remains the further debatable question: Is indefinitely pro-\nlonged exposure to radiation of radioactive substances harmful, however slight\nthe radiation? The evidence readily available is ample to furnish a conclus-\nive answer to this question.\nThorium is a radioactive element which is extensively used in the manu-\nfacture of gas mantles. The workers in thorium plants and in mantle factories,\nthough constantly exposed to the radiation of thorium and of mesothorium (which\nlatter closely resembles radium), have never been known to suffer ill effects from\nsuch exposure.\nI may cite a case with which I am intimately familiar. Lindsay Light\nCo. (of which company I am vice-president) has operated a plant making thorium\nnitrate for 14 years. During the past 13 years two men, Stabneau, Supt., and\nFlynn, foreman, have been steadily employed at this plant. Both these men have\nbeen exceptionally free from all kinds of illness and both today are in excell-\nent health. In the course of 13 years they have handled and been exposed\nto an amount of mesothorium equal in radio activity to about 14,000 milligrams\nof radium.\nIn their mantle factory, Lindsay Light Co., have had for years 100 or\nmore girls employed in making mantles. All such mentles are radio active,\nyet I have never known of any ill effect from exposure to radiation in that\nfactory.\nMillions of people wear watches with luminous dials, without the least\nharm.\nOn the other hand, the beneficial effect of drinking and bathing in the\nwaters of certain famous Spas has been credited to the fact that such waters\ncontain appreciable amounts of radium (see Government bulletins on the radio\nactivity of the waters of Hot Springs, Ark., for example). Some physicians\nadvocate the use of water to which radio active substances have been artific-\nially added. I am not prepared to say from direct knowledge what the result\nto the patient has been; but I have not heard of any ill effect and much\nbenefit has been claimed.\nIf one wishes to go to extremes, it can be said with absolute accuracy\nthat everyone in the world is at all times (and no doubt has always been, for\nthat matter) subject to faint radio active exposure. Accurate researches, first\n-3-\nmade 15 or 20 years ago, have shown that radium and radio active matter is to\nbe found in minute amounts everywhere in the workd, not only in ores but in all\nrocks, all earth, all natural waters, and in the air. Natural air everywhere\ncontains an easily determinable amount of radio active matters. Some 15 years\nago, working at the University of Chicago, I was able not only to detect, but to\nmeasure with fair accuracy, the quantity of radium emanation in as little as 4\ncubic feet of natural, out-of-door air. This work has since then been amply\nconfirmed by other reliable investigators.\nThe conclusion to be drawn from the evidence here cited is that slight\nor moderate exposure to radio active matter is harmless.\nFurthermore, if it is suspected or claimed, in any specific case, that\nharmful effects are being produced by exposure to radio active substances or\ntheir radiations, it is not sufficient to show that there is some exposure; but\nit must be definitely determined whether the exposure is great enough to cause\nnoticeable injury.\nThis fundamental distinction may need additional consideration, for the\nreason that exposure to radio active material differs in an essential manner from\nexposure to germs of infections diseases. Such germs are always dangerous in\nthe most minute quantities. Indeed, a single germ, brought into the body, may\nproduce the corresponding disease with results as disastrous as if the infection\nhad started with millions of such germs. The reason is obvious: under favorable\nconditions, germs multiply without limit, radio active matter never multiplies.\nExposure to radio active radiation may be likened to exposure to sunshine.\nA certain amount of such exposure is beneficial and even necessary for health;\nbut over exposure results in sunburn and excessive sunburn has been known to\ncause death. So it is with radio active radiation; a little is harmless; a great\nexcess is dangerous.\nWhat then is the dividing line that separates harmful radiation from\nharmless? That is just the question that still is attracting much attention\nfrom those working in this field. I doubt whether a satisfactory answer has yet\nbeen found. However, a few generalizations may be permissible. The region\nbetween dangerous radiation and harmless radiation is doubtless a broad one --\nthere is no sharp line of demarkation. The element of length of time of exposure\nis an all important factor. Also analogy would lead one to expect that various\npersons would not tend to be equally affected by equal radiation; and further\nthat good habits and good personal hygiene would favor resistance to ill effects.\nThe use of dental films offers a valuable means of discovering roughly\nthe amount of radiation in a definite location. Such tests must be made skill-\nfully and in comparison with suitable controls if they are to be of real value.\nBlood counts on persons subject to exposure are apparently the surest\nmeans of discovering the extent of the less obvious effects of radiation.\nComments on Dr. Drinker's Report.\nA. Dr. Drinker reviews 5 principal and 3 minor cases, specifying the\n-4-\nnature and the extent of the injury in each case. I get the impression that the\nfacts set forth in the report are quoted from records, rather than deduced from his\nown observations. I am not in a position topass judgment on his conclusion that\nthese findings are unusual as to numbers of persons affected with this uncommon\nmalady. I note that no unusual or harmful condition, except possibly radium hazard,\nwas found in the factory; with the result that Dr. Drinker concluded that the observed\ntrouble must have been caused by radium.\nIt seems to me that this conclusion is not proven; (1) because the malady might\nhave been due to some other unknown cause; (2) because it is not shown that the actual\nexposure to radium was sufficiently great to cause the observed necrosis; (3) I\nunderstand that another dial painting factory has not had similar trouble. Dr. Drinker\ncites well known physiological effects produced by radium radiation when the active\nagent is external to the body. He then speculates on the effect of smaller amounts\nof radium inside the body; but no experimental data or quantitative results are\ngiven; nor is it shown by any tests how much radium, if any, has entered the body in\nany case.\nThe conclusion that the cases of necrosis were caused by exposure to radium\nseems to be based on the ancient (but fallacious) maxim: post hoc, ergo propter hoc --\nafter this, therefore on account of this:\nGoing on to the next topic, I note that working conditions in the factory were\nfound to be good, even pleasant, and that no hazardous material (other than radium)\ncould be found. The detection of zinc sulphide on the clothing and persons of\noperatives was taken to indicate that radium also must have been present, although its\npresence could not be demonstrated. No radium was found in dust collected in the\nwork rooms. There should have been no difficulty in detecting and even in determin-\ning the amount of radium on clothing or in the dust, if it were there in amount\nsufficient to do the least harm.\nAn investigator, skilled in the art of radio activity measurements, if he had\nfound \"no radium\" would have stated the minimum amount he could have detected. The\nreport leaves us to guess whether this minimum was a microgram or one thousandth of\na microgram. The last mentioned amount could have been found easily by a trained man.\nIt seems to me that when Dr. Drinker states, top of page 6 of his report:\n\"It is however impossible to assert because no radium has been detected in the dust\n(The dust being demonstrably derived from \"Undark\") that it therefore contains no\nradium. If he tacitly admits his lack of adequate skill as an investigator of a possible\nradium hazard.\nUp to this point, the report seems to contain but little information with\nwhich the officers and other responsible men of your company were not already familiar\nor which they could not have discovered by a cursory examination. The remainder of\nthe report deals with three topics: (1) the examination of the teeth of a selected\ngroup of your employees; (2) the examinations of the blood samples from the same group;\n(3) a survey of the stray gamma radiation in portions of your plant by means of\ndental X-rays films. The results of the first and second of these studies are set\ndown in tables 1 and 11.\nBeing only a chemist and not a dentist nor a physiologist, I am not able to\ndetermine to what extent the reported conditions deviate from the normal to be\n-5-\nexpected for groups of persons of like status in life engaged in other occupations.\nI note that in table 11 data for \"normal persons\" are given and I wonder whether\nappreciable variations from \"normal\" values would be found for groups of persons\nof like status in life, from other industrial fields, just as in the case of your\nemployees.\nThere is no doubt that tests with dental X-rays films if made skillfully\nand with comparison with suitable \"blank\" controls are of great value in showing\nthe amount of stray gamma radiation in a building containing radio active material.\nThe method of exposure and of development of such films must be strictly standardized\nto be reliable. The degree of blackening of a film indicates the amount of\neffective radiation to which a person located in the place occupied by the film would\nreceive in the same period of time. Better still, a suitably wrapped film carried\nby a person exposed to variable radiation should show the total exposure during the\nperiod it is carried. After it has been established that fogging or blackening of\nfilms occurs under the conditions just considered, it becomes a matter of prime\nimportance to know just how much effect per day, week, or month is dangerous.\nPerhaps the limit said to have been established by Pfahler is reliable; but as I\nhave not done any work along this line, I am not competent to express a first-hand\nopinion. It seems to me that one would be warranted in making the tentative\nassumption that the extent of the observed blood abnormalities correspond roughly,\nthe data being properly \"weighted\", to the amounts of radiation indicated by the\ndental film tests.\nHOTUIDO me\nconclusive evidence that radio active materials were causing the condition\nexisting among certain of your employees -- referring hereby to the observed cases\nof decayed or abscessed teeth, pyorrhea and necrosis of the jaw bone. On the\nother hand, the fact that there was some stray gamma-ray radiation and noticeable\nblood abnormalities in some individuals shows that there existed some unusual con-\nditionss that might well have been the predisposing causes of the known trouble.\nBut to claim that because unusual conditions were found that it was conclusively\nproved that these conditions caused the teeth and jaw troubles is to go beyond the\nevidence. Is it not conceivable that teeth and jaw infections may be carried\nfrom one person to another just as typhoid is often transmitted to every one in a\nhousehold by a cook who is \"typhoid carrier\"? Possibly the interchange of brushes\nand the habit of \"pointing\" would account for the spread of germ infection from\none person to another.\nI am reminded of the well known history of yellow fever. Thirty years\nago throughout the American tropics this disease was quite generaly believed to\nbe due to the poisonous effect of \"night air,\" with the result that at night fall\nbedrooms were tightly closed. Now we know that the disease is transmitted only by\nmosquitoes that have become carriers as the result of having bitten a human that\nis a victim of the disease. Today Havana is a highly healthful city. There is\nno yellow fever although for the most part the windows are not glazed nor screened\nand \"night air\" is no longer considered poisonous. The history of malaria\npresents a. similar picture. Since man's sum of knowledge is not complete, it\nseems possible that there may still be something to learn about the cause of necrosis\n-6-\nof the jaw: exposure to slight radium influence may not be the cause of this malady.\nI do not mean to imply by the foregoing comments that although your executives\nin 1924 may have considered the case against radium exposure as the cause of the\ntrouble as \"not proven,' that nothing should have been done about it. On the\ncontrary, it would have been well to have adopted such measures as were practicable\nto diminish radium exposure of dial painters to a minimum, on the suspicion that\nsuch exposure might be the cause of trouble. I do not know what action, if any, your\ncompany took at that time. The following procedures occur to me as tending to\nbring danger of exposure to a negligible state.\n1. Luminous paint to be mixed preferably by automatic mixers at a distance\nfrom the dial painting rooms, and brought to painters as a wet paste in small portions.\n2. Finished dials to be removed from painting room at frequent intervals --\na belt conveyer could be used.\n3. Paint brushes should be thoroughly sterilized by heat before being issued\nto dial painters. (Anthrax hazard).\n4. The pointing of brushes in the mouth should be strictly prohibited and a\nstandard technique substituted and rigidly enforced. If pointing was still occasion-\nally detected, brushes could be washed and sterilized daily. The brush issued to\none person should not be used by any other.\n5. Good ventilation of the painting room would remove dust and radium\nemanation as far as possible.\n6. Lead screens of 1/2 to 1 inch in thickness, arranged as in your crystalling\nlaboratory (which I saw 3 or 4 years ago) could be used to give each painter a large\nmeasure of protection from the very slight gamma ray activity of the paint being used.\n6. Ample lavatory facilities and enforced rules about washing up thoroughly\nat noon and night would reduce the ingestion of radium to a minimum.\n7. Weekly or monthly dental inspection, and service where necessary, with\ninsistence on good dental hygiene, would go far toward the prevention of all dental\ntroubles and insure the early detection of any abnormal influences.\n8. It might also be advisable to discourage employees from working at dial\npainting for more than a year or two. Medical and dental examinations of new employ-\nees would eliminate all below normal.\n9. Finally, a complete solution of dial painters hazard, whatever its cause,\nwould result from the invention of an automatic machine to paint dials. Such a\nthing ought not bo be impracticable.\nIn conclusion, since this report may come into the hands of persons who\nare not acquainted with the writer, it may be advisable to state that I am not a\nphysician, nor have I studied thoroughly the literature of the physiological effects\nof radium. My criticisms and comments are those of a chemist who has had 25 years\nof experience in experimental work with radio active substances and who has also been\nconnected with the technical production of the radio active elements, uranium, radium,\nthorium, and mesothorium for the past 13 years.\nChicago,\n(signed) Herbert N. McCoy\nJanuary 23,1928."
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