I am pleased, however. to announce that such a core medical examination has been proposed by the physicians sub-committee of the Occupational Safety and Health Administration standards group of the Organization Resources Counselors Inc. It has been presented to the National Advisory Committee on Occupational Safety and Health and has been favorably received. We have learned that this scheme will probably be adopted, at least on a trial basis, to be used when such examinations are given to employees of the Occupational Safety and Health Administration of the U.S. Department of Labor. This is a very encouraging development. RECORDKEEPING AND SURVEILLANCE I must point out that our intent was not to encourage OSHA to require examinations of all employed persons. Rather, it is an attempt to standardize OSHA required exams to facilitate compliance, better worker protection, and to aid physicians in doing a better job. Industrial Hygiene Monitoring Implicit in any venture to protect the health of workers from potentially hazardous agents is a suitable and effective appraisal of actual work place exposure levels. All too often in the past there has been an inadequate history of potential exposure and a lack of precise analytical monitoring. Great strides in developing precise analytical methods have been made in recent years and this effort needs to be pressed vigorously. It is obvious that such data should be coordinated with health surveillance systems: but too often this is not done or not properly understood-especially and understandably by physicians unfamiliar with industrial concerns or toxicological principles. In this sphere of interest it is essential that there be concern for the possible influence of other unknowns such as coincidental exposures. contaminants in even trace amounts, and variations in content that may occur from time to time. In no way do I wish to imply or even suggest that industrial hygiene analytical and related functions are in any manner less important than we have always considered them. They are, in fact, the cornerstone and basic foundation of our planning to prevent ill effects from toxic and other harmful effects in the work environment. In my judgment, purely industrial hygiene measures have con. tributed more than have purely medical activities in reducing the effects of toxic substances, radiation. and other forms of energy. noise. heat and cold stress. excessive work effort, and many other potentially harmful influences on our working people. Nevertheless, the most diligently applied industrial hygiene programs are inherently beset with the possibility of failure in that they cannot possibly provide absolute assurance that the worker is safe. Even if 62 Threshold Limit Values are observed scrupulously, there is no assurance that the individual adheres to practices that preclude excessive exposure. Breaks in techniques of safe working practices, such as unplanned skin exposure or handling contaminants just prior to meal time or smoking can totally invalidate the most exactingly careful precautionary plans. Newer methods utilizing personal sampling monitors which continuously measure the individual's actual environmental exposure may help greatly. but they do not take into account transdermal absorption or any failure based upon sudden, brief exposures at high levels beyond the capability of the instrument to cope. If fail-safe, continuous personal monitoring equipment capable of handling all levels of exposure with reliability are developed, then, except for dermal or oral exposure possibilities. health surveillance might no longer be needed for routine industrial health control. However, as Stokinger has indicated, air-borne concentrations as an index of exposure are also unreliable in situations of mixed exposures with metabolic interaction, individual peculiarities of work habits leading to abnormal intake, and additive exposure off the job. By reflecting all of the possible variables, health surveillance may become sufficiently advanced to provide both an index of exposure and an index of response. Accordingly, only health surveillance techniques, if available for the specific exposure, could ascertain that the individual worker is completely safe and has incurred no adverse effects. Much research and development of new methods is needed before that comfortable condition obtains. In interim it must be hoped that there is sufficient understanding and wisdom to accept the unavoidable but serious limitations with which we are now shackled. Epidemiology The epidemiologic record related to occupational health and illness (and for that matter, of natural disease, too) traditionally has been appallingly inadequate. Without a valid and usable base of health surveillance and related worker exposure data, the best of epidemiologic schemes will be of only crude quality. This provides cogent emphasis as to the need and 63 importance of auditing and scientific assessment of the results of our surveillance programs. Disability and Workers' Compensa. tion The quantification of disability and determination of the degree attributable to Occupation truly defies or eludes us technologically today. This precludes the other perspectives of concern (moral, legal, and economic) from being dealt with objectively on a wholly fair and rational basis. Certainly exacting and proper recognition of occupational disease or adverse effects in the input side of the equation is the weakest link in the entire process. No magic answers are apparent in the immediate offing and there is a great need for long-term follow-up of the natural history of disability and its relationship to compensation practices. This particular consideration may not seem related to my topic-but this, plus our humane efforts. becomes the "bottom line" when we fail. All of these issues indicate that there are many unsolved matters and that our work is clearly cut out for the future. It is obvious that there is an abundant need and clear urgency 'for major change and realignment of priorities and policies for overall national and occupational health care delivery systems. In order to achieve a successful capability for health surveillance of workers, several special needs emerge: 1. Record systems are critical and much needs to be done to make them more meaningful. Computerization is absolutely essential for correlation with work environmental data, comparative studies, proper and required record retention, and the audit function. Compatibility between systems on areas of primary concern is essential. This in no way precludes individual organizations from embellishing the scope to whatever extent they desire. 2. Improved science is imperative. Despite the remarkable advances in analytic capability, especially in the chemical area, much more is needed and capability in the biomedical sciences is far behind. This lag has, in fact, aggravated our problems in that RECORDKEEPING AND SURVEILLANCE Mr. GORE. Thank you very much. We will withhold questions until the other members of the panel have concluded their presentations. I'd like to invite my colleague to deliver his opening statement if he wishes. Mr. WALKER. Thank you, Mr. Chairman. What I would like to do is just ask unanimous consent that the statement be included in the record at the opening of the hearing and let the witnesses go on. Mr. GORE. Fine. Without objection. Dr. Weill, we would like to hear from you. Thank you for coming. STATEMENT OF HANS WEILL, PROFESSOR OF MEDICINE, TULANE UNIVERSITY Dr. WEILL. Thank you. Mr. Chairman, members of the committee, and the staff, I'm pleased to have accepted the invitation to participate in these hearings. I am professor of medicine at Tulane University at New Orleans and I direct a multidisciplinary research unit in occupational lung diseases funded by the National Heart, Lung and Blood Institute through a specialized center of research grant. Our interests in hazardous exposures found in the workplace vary widely and include mineral dusts, silica and asbestos, organic dusts, cotton, and irritant gases and chemical vapors, chlorine, isocyanates, and formaldehyde. It is the intention of my colleagues and me that the scientific product of our research efforts be utilized in the prevention of occupational lung diseases, acute and chronic disorders which are all potentially preventable. Much of the scientific approach that we employ depends upon the investigation of working populations, both past and present, quantification of their respiratory health, and characterization of their environmental exposures. Ultimately, correlations of the biological and environmental data lead to information concerning dose-response relationships, and, very importantly, how these may be modified by personal or host factors of the worker himself or herself. The lungs and the airways are unique organs in that they are in constant contact with the inhaled environment and therefore are susceptible to injury from hazardous inhalants. These respiratory diseases that are of interest to our investigative group are invariably multifactorial in cause and they are likely to have as determinants both genetic and environmental factors, and in the latter, using the term in the broad sense, I would include obviously such factors as smoking and infection. Now in the former, there are some specific genetic aberrations that increase the risk of developing certain respiratory diseases. It's clear that the most effective approach to the prevention of these disorders would be a determination of susceptibility to developing the respiratory disorder and, if that susceptibility could be dichotomized-that is, yes or no-the preclusion or exclusion prior to employment of all those found to be susceptible. Regrettably, such is not often the case in the real world. It's just usually not possible to do this prior to employment or exposure. However, epidemiologic studies of populations exposed to workplace inhalants may identify both exposure and host characteristics which result in increased risk for the development of the adverse respiratory effect, and such risk-thanks to the efforts of our statistical colleagues-are in fact quantifiable. While occasionally this may be possible with our present state of knowledge prior to the time of exposure, therefore leading to the possibility of preemployment screening for high risk individuals, most often indicators of increased risk emerge following initial exposure which may, however, still lead to removal from such exposure before advanced or possibly irreversible respiratory injury has taken place. My first point, therefore, is that while preemployment screening is currently at a very early state of development in meeting the objectives of occupational lung disease prevention, much of the effort probably is going to depend on careful medical surveillance of employed and exposed populations and this careful surveillance even early during employment will in fact serve a similar function. In our investigative field, there are three major exposure-related respiratory health effects of concern: (1) diffuse pulmonary fibrosis, such as the pneumoconioses, silicosis, and asbestosis; (2) there are acute and chronic airways diseases, the former represented either by occupational asthma or acute bronchitis, and the latter by chronic industrial bronchitis; and (3) the very important occupationally associated respiratory malignancies. Now dealing with the third category first-that is, the malignant consequences of occupational exposures-it is reasonably safe to indicate to you that we currently have no method to predict which individuals are at increased risk due to genetic factors of developing respiratory cancer. We know, however, that in essentially all occupational causes of respiratory cancer this risk is importantly influenced by cigarette smoking. The interaction between the occupational agent and smoking is substantial, and it is widely agreed that the risk of occupational lung cancer would be strikingly diminished-not eliminated but diminished-in the absence of smoking. The scientific community can produce quantitative estimates of risk, but society and their representatives must decide how to intervene in minimizing these risks. The risk of developing pneumoconiosis is invariably dose-related in that the higher the average and cumulative exposure, the greater the prevalence and severity of diffuse pulmonary fibrosis associated with this exposure. This has been demonstrated by our group and others in asbestosis and silicosis, but it has not been possible to identify immunologic or personal factors which lead to susceptibility to these conditions. While certain immunologic markers are noted with increased prevalence in workers who have mineral dust diseases, there is no evidence that these serve to predict the condition rather than appearing after the disease is well established. I might just point out to the committee that, in fact, this is a problem in a number of instances. There may be a marker. The question is, does that marker pre-exist-that is, predate the onset of exposures, or is it simply an attendant consequence of the effects of exposure? And I think that distinction will obviously be important in the development of some concepts of prevention of these conditions. |