Representative PRICE. You brought that out in your own statement. Mr. PARKER. Excuse me, sir. I didn't hear the question. Representative PRICE. You brought that out in your statement this morning as to the level of acceptability. Mr. PARKER. Yes, in other terms. Representative PRICE. That is all I have, Mr. Chairman. Representative HOSMER. In discussing the threshold theory and discarding it in your hypothesis, at least, you made the assumption that it is generally conceded that radiation of any amount causes changes that are deleterious. Yet we find man evolving what we think is upward in quality as an animal in a background environment of radiation. How do we reconcile that? Mr. PARKER. Mr. Hosmer, let me attempt to answer that question in two parts, or perhaps more honestly to answer the first part and duck the second part. The answer to the first part is that one has not said whether one is discarding the threshold effect. Merely one says that the evidence is incomplete, and this is the key technical problem that has to be resolved. In the absence of its resolution you select the approach to the problem that will seem to be the most conservative, which is to accept the no-threshold effect. This implies to some degree additivity of deleterious genetic effects through all the generations, as you mentioned. Why I divided the question into two parts is because I do wish to duck the firm response to the second part on the grounds that I have made some point of the great mistake that many of us make in stepping well outside of our bounds of professional qualification. The question you ask, I believe, sir, is one in which the geneticists have a useful contribution to make, and which I as a layman from the genetics point of view have tried hard to understand in full. would make no real contribution by making a definitive statement and so using the opinion of the geneticists at secondhand. I do recommend that the point be addressed to a suitably qualified witness later, sir. I Representative HOSMER. In that connection, I think one of the points that was made in the paper by Harris 2 is the fact that these standards should not be established by physicists or any particular discipline alone, since they involve matters of economics, sociology, and things of that nature, they necessarily should be established on the basis of a diversified committee coming to some general agreement. Is that essentially what our problem is? Mr. PARKER. This is essentially built into the language that I have tried to use this morning as to value judgments. Representative HOSMER. You mentioned the importance of public understanding in obtaining the acceptance of whatever standards might eventually be evolved. How do we overcome the very difficult problem of terminology? In the preprint we have set forth a special table of terms. You have used several different expressions in your testimony that I think only the real experts can grasp at first hearing sufficiently to bring to mind the concept of their meaning. 2 See Selected Materials, pp. 49 and 50. What I am essentially getting at is that, although the general public doesn't know what a watt is of electricity, they have an understanding whether they want a 50-watt or 70-watt or 100-watt light bulb. They go down and buy one. Is there any key of that nature that can be developed so that public understanding of radiation can be facilitated? Mr. PARKER. This is again not an easy question to answer. Let me say first that by the time we have had our present battery of radiation units in practical use as long as the term "watt" has been in use, I believe its degree of familiarity to the public will be about equal. At the present time it is not so large. There is a complex battery of radiation units which was in fact only developed and used in a small coterie of atomic energy projects, beginning in about 1943. These were promulgated, beginning about 1946 or 1947, to a wider audience, and have gone through the process of what you might call clinical trial and error which have caused them to be modified. So we have arrived by more or less agreement of the scientific fraternity at two units in current use which have some continuing substance, although a limited substance. Of these two, the physical one, which is known as the rad, is a measure of expression which I believe can be with confidence promulgated to all and its meaning known through standard forms of teaching. The unit rem has a different character in the sense that it is not as significant a unit in the absence of the arbitrary scale of relation that I mentioned that defines applicable radiobiological effectiveness values for all of the particular cases. This multiplies the task of teaching to the public the true meaning of such a unit. One should not put some numbers on this because it has no numbers. It is an order of magnitude more difficult to convey this meaning to a large audience and not have the next speaker inadvertently convey quite a different meaning. Representative HOSMER. As a matter of fact, in the instructions you received as a witness you were told to deliver your testimony in terms understandable by the layman. You have found it impossible to comply with that instruction, have you not? Mr. PARKER. This is what you are saying. This means that we have failed in an attempt to reduce the language to generally understandable terms without further elaboration. Representative HOSMER. The reason I pursue this line of inquiry is merely to emphasize that, along with all the other problems that may be mentioned during these hearings, communications and terminology are important ones to solve in order to achieve what we seek-acceptable standards in this whole area. Just for the purposes of the record, I think you have indicated that the average person obtains about three rem of irradiation from diagnostic X-rays during his lifetime. What contribution does one chest X-ray make to that? Mr. PARKER. The number that is conventionally written down for a chest X-ray depends on whether we are talking about the fluoroscope process or look-see process or the actual radiographic process or taking the photograph. The look-see or fluoroscopic process is normally charged between 1 and 2 roentgens as a representative value for the chest. You must recall again, sir, that the actual radiation dose will vary at all points on the chest in this procedure. Taken as a radiographic photographic process, the necessary dose is generally taken as about one-tenth of that in the look-see method, or one-tenth to two-tenths of a roentgen. Representative HOSMER. In other words, the fluoroscopic procedure gives a relatively high dosage. Mr. PARKER. Very much higher than the photographic process. Its justification is that only by a fluoroscopic or direct look-see process or some indirect sort of moving sequencing can you get the sense of motion which is needed for the clinical examination in some cases. It does not say that fluoroscopy should be used where radiography satisfies the inquiry of the physician. Representative HOSMER. I think you indicated it has between 100 and 200 for a photograph. Mr. PARKER. I think those are generally taken as representative. Representative HOSMER. Thank you. (The following supplementary information was submitted for the record by Mr. Parker :) On Tuesday, May 24, I endeavored to answer a question from Representative Hosmer on the amount of radiation received during chest radiography. As I recall, I quoted a dose of about 1 roentgen for the indirect fluoroscopic method and a dose of about 100 to 200 milliroentgens for direct radiography. These numbers are appropriate for the average dose received by the chest region in such practices. However, it is now clear that the intent of Mr. Hosmer's question was to determine representative dose to the reproductive organs. Such doses are broadly in the range of 0.1 to 0.5 percent of the numbers quoted. There is a wide variation in the actual dose to the reproductive organs during these procedures. The range of reported values that I find is from 0.01 to 3 milliroentgens. It may be noted that Dr. Chamberlain on Wednesday, June 1, quoted numbers which range from 0.1 to 0.5 milliroentgens using modern techniques. There is no particular discrepancy between our figures, since mine include, at one extreme, very low values obtained with special methods not yet considered to be general modern practice and, at the other extreme, the high values connected with the fluoroscopic method. Representative BATES. I want to touch on the same point that Mr. Hosmer made relative to an informed public. After listening to your statement, realizing the magnitude and complexity of the problem, we come to the point where you indicate the public should be informed. This appears rather difficult and particularly after I read part of your statement where you say taking points 4, 5, 6, and 7 together, man gets so subdivided between space and time and radiation types and radionuclides that the base integrating sense of standards is lost. Those are the words of an expert in the field. I wonder how we can at this time inform the public? You indicate that this authority of knowledge should be accepted, I presume, by faith. People who are experienced in the field are working on it. People cannot measure in their own minds the terms that we use, rems and rads. They can understand a foot or a pound or something like that. Particularly when the experience of damage in the field has been so limited. People have been burned by fire, and they can understand the dangers there. They drown in water, and they can understand that. What can you say in a brief statement that would at this time inform the public in addition to the fact that they should have faith in the people who are working in the program? Mr. PARKER. These are some of the most significant points in the whole affair, Mr. Bates. Let me say this, that one is faced with this enormous mass of preprint material and in a first review of it, one perhaps emphasizes the difference in contempt and presentation of the intended witnesses. But if one steps back a pace and takes a more objective view, I believe it is proper to say that there is a remarkable degree of uniformity on the keypoints throughout this preprint material, and thus, I believe, throughout the material that will be presented. If these 2 weeks of hearings emphasize the point that although some of us tend to quibble on the third decimal place of some expression of limits, on certain key points there is almost unanimous agreement among those perhaps qualified to have competent opinion. This, I believe, is what will tend to establish in the public this feeling of support of knowledge of those who are currently working in this field. I would consider it, in detail, hopeless to inform the public on all the ramifications of all the handbooks put out by responsible bodies in this field. But I do think that certain basic principles can be shown here to be agreed upon by those qualified, and that this provides the basic assurance to the public that very probably the fine points are under much better control than they occasionally see when one tends to rather emphasize the difference in expression rather than the basic similarity. Representative BATES. As you know, there is a good deal of fear in the minds of many people concerning the possible effects of radiation. That has been expressed in many forms, whether it is ocean disposal in my area, or other places throughout the country. You indicate that faith in people is one thing. But it is difficult for people to accept something merely on faith, especially when they don't understand it, and as you indicate, the details are so far reaching that they could not possibly understand it anyway. Mr. PARKER. There are some points in this area which I am sure will be clarified in these 2 weeks, some which I rather consciously left out of what was intended as a summary. One point is the fear in the minds of many that if one goes slightly beyond some written limit, some dire consequence will occur. We establish a limit perhaps in some cases of 5 rem per year. I am sure there is a feeling in some areas that if any individual has been exposed to 6 rem his life is ruined. I believe that the responsible witnesses will show the fallacy of any such line of reasoning during this period. This may make a real contribution. Representative BATES. Of course, the uncertainties of any new field make people much more suspect and much more reluctant to accept something new than something that they have lived with for a long time. For instance, automobile accidents, 45,000 deaths a year. If that was part of this program we would have to close up the shop right away. People would never accept that. Mr. PARKER. The program is bedeviled by its own past excellence compared with other protection programs plus the demand for many other investigations needed. This is what I referred to as the second implied need for balance in our national structure, a perspective in respect to hazards of all kinds. Representative BATES. All of this will be developed as the hearings proceed? Mr. PARKER. I hope to hear it so developed, sir. Representative HOLIFIELD. There was one or two points I would like to pick up at this time in reference to the general understanding of this matter. Of course, these hearings will not be read extensively by the lay public. Neither will this compilation of data in the preprint be studied by the lay public. I am speaking generally now. There will be individuals who will. The important contribution, I think, that the contributors will make, and that the committee can make in pulling this material together is to offer to those people in responsible positions a compilation on the subject which will allow each of these people to peruse the status of technology and the status of thinking of the different experts which contribute toward it. We have asked you to put it in lay terms as nearly as possible and lay words that is so the committee may understand it. We know the difficulties you are faced with. Part of that difficulty, as Mr. Hosmer so well pointed out, is the use of these terms. Is it possible for your groups—I am speaking now of the national and international radiation groups—to develop a glossary of words, such as criteria, standards, and so forth, and arrive at a common meaning of words, such as we have done in the cases of rad, rem, rep, roentgen, and so forth, in the glossary of terms in our preprint. There may be differences of opinion as to the definitions of these words, but we have tried to put a common definition which is commonly accepted among experts as to those terms. In setting up standards, is it possible for your groups to arrive at a common meaning on key words, and have them in a special glossary such as we have here so that when we are talking about criteria or standards or any other commonly used word that is descriptive, that we can define it a little more closely than the ordinary English definition of the word when it is used in common ways would permit? Mr. PARKER. I am glad you brought up this point. I would conceive it to be quite simple to do this with respect to such words as criteria, standards, and guides, certainly in a comparison with the attempted resolution of words like rem. Representative HOLIFIELD. There is such a variation in the meaning of the spoken word in the individual's mind, if we could pin those words down a little more accurately in the hearing, I think it would be quite helpful. Mr. PARKER. Yes, sir. I hoped to suggest that we could save time by devices like this of which the introduction of these charts was intended as an example, so we can save the time of the committee. Representative HOLIFIELD. I think it is very good that we discuss it in terms of these charts. I understand that they are pretty well agreed upon, or at least the differences are shown between a threshold and a nonthreshold. When you are talking about one or the other, it is certainly understood as to what you mean. I am concerned about the setting of these standards on a nontechnical basis. Where the setting of the tolerable dose or the maximum permissible dose would be adjusted to an economic pressure, for example. I notice in your Federal Radiation Council staff report of May 13, under the term of "atmospheric contamination of uranium mines," paragraph 6.20 In addition to the current recommendations of the NCRP, the American Standards Association (ASA) has been active in the establishment of recommendations in this field concerning air contamination from radon and its daughter products. |