Opinion ID: 326929
Heading Depth: 2
Heading Rank: 2

Heading: The Discharge Into Water.

Text: 83 The claim that Reserve's discharge of tailings into Lake Superior causes a hazard to public health raises many of the same uncertainties present with respect to the discharge into air. Thus, the previous discussion of fiber identity and fiber size is also applicable to the water discharge. In two respects, however, the discharge into water raises added uncertainties: first, whether the ingestion of fibers, as compared with their inhalation, poses any danger whatsoever; and second, should ingestion pose a danger, whether the exposure resulting from Reserve's discharge may be said to present a legally cognizable risk to health. 84
85 All epidemiological studies which associate asbestos fibers with harm to health are based upon inhalation of these fibers by humans. Thus, although medical opinion agrees that fibers entering the respiratory tract can interact with body tissues and produce disease, it is unknown whether the same can be said of fibers entering the digestive tract. If asbestos fibers do not interact with digestive tissue, they are presumably eliminated as waste without harmful effect upon the body. 86 The evidence bearing upon possible harm from ingestion of fibers falls into three areas: first, the court-sponsored tissue study, designed to measure whether asbestos fibers are present in the tissues of long-time Duluth residents; second, animal experiments designed to measure whether, as a biological phenomenon, fibers can penetrate the gastrointestinal mucosa and thus interact with body tissues; third, the increased incidence of gastrointestinal cancer among workers occupationally exposed to asbestos, and the hypothesis that this increase may be due to the ingestion of fibers initially inhaled. 87
88 Recognizing the complete lack of any direct evidence (epidemiological or otherwise) on the issue of whether the ingestion of fibers poses a risk, the trial court directed that a tissue study be conducted to determine whether the tissues of long-time Duluth residents contain any residue of asbestoslike fibers. 89 The study sought to analyze by electron microscope the tissues of recently deceased Duluth residents who had ingested Duluth water for at least 15 years; that is, approximately since the beginning of Reserve's operations. As a control check on results, tissue samples were obtained from the deceased residents of Houston, Texas, where the water is free of asbestos fibers. Although this study was necessarily expedited, plaintiffs' principal medical witness, Dr. Selikoff, testified to the sound design of the study and expressed his belief that it would yield significant information. 90 One of the court-appointed experts, Dr. Frederick Pooley, 41 in explaining the results of the study, stated that he found that the tissues of the Duluth residents were virtually free of any fibers which could be attributed to the Reserve discharge. Dr. Brown said of this study: 91 It is my conclusion, from the tissue study, that residents of Duluth have not been found to have asbestiform fibers in their tissues when compared with Houston. (A.23:208.) 92 As we noted in the stay opinion, the parties dispute the significance to be attributed to the results of this study. Dr. Selikoff, prior to the conclusion of the study, expressed this view: 93 Now, our feeling was that no matter what air samples show or water samples show or anything else, unless it is found that asbestos is in the tissues of people who have drunk this water    if we do not find it in the tissues in appreciable quantities, then I would risk a professional opinion that there is no danger, at least up to this point, to the population no matter what our samples show or water samples. (A.11:95.) 94 After negative results had been actually obtained, however, plaintiffs argued, and the district court agreed, that because the specimens of tissue represented only a microscopically minute body area, the actual presence of fibers may have been overlooked. 42 95 We note that this limitation had not seemed dispositive prior to the study when Dr. Selikoff commented: 96 I would think we should find some fibers there. We're looking for needles in a haystack, but that's all right, we should find needles in the haystack with all the difficulties of the study, the technical difficulties, if we examine sufficiently large numbers of samples in some instances we should find some fibers there. (A.11:77.) 97 The district court decided, and we agree, that the study cannot be deemed conclusive in exonerating the ingestion of fibers in Lake Superior water as a hazard. The negative results must, however, be given some weight in assessing the probabilities of harm from Reserve's discharge into water. The results also weigh heavily in indicating that no emergency or imminent hazard to health exists. 43 Thus, while this study crucially bears on the determination of whether it is necessary to close Reserve down immediately, the negative results do not dispose of the broader issue of whether the ingestion of fibers poses some danger to public health justifying abatement on less immediate terms. 98
99 At a somewhat more theoretical level, the determination of whether ingested fibers can penetrate the gastrointestinal mucosa bears on the issue of harm through ingestion. If penetration is biologically impossible, then presumably the interaction of the fibers with body tissues will not occur. 100 This medical issue has been investigated through experiments with animals which, unfortunately, have produced conflicting results. For example, Reserve witness Dr. Davis reported on his experiment in feeding crocidolite and chrysotile asbestos to rats for varying periods of up to six months. He killed the rats at the end of the period and examined their gastrointestinal tissues for evidence of fibers. At the time of trial, light and electron microscopy had so far revealed no evidence of fibers in the tissues. (A.16:143-59.) 101 Plaintiffs, however, cited contrary studies. Research by George Westlake, in which rats were fed a diet including chrysotile fibers, indicated that fibers had traveled through the colon wall and accumulated in the area of the mesothelium. 44 (A.11:23-25.) Pontrefact, who injected chrysotile fibers into the stomachs of rats, found that fibers had dispersed throughout the body tissues. 45 (A.11:37-41.)On this conflicting scientific evidence, Dr. Brown testified that the Westlake and Pontrefact studies provide some support for the hypothesis that asbestos fibers can penetrate the gastrointestinal mucosa. 46 102
103 The affirmative evidence supporting the proposition that the ingestion of fibers poses a danger to health focuses on the increased rate of gastrointestinal cancer among workers occupationally exposed to asbestos dust. Plaintiffs' experts attribute this excess incidence of gastrointestinal cancer to a theory that the asbestos workers first inhaled the asbestos dust and thereafter coughed up and swallowed the asbestos particles. 104 The attribution of health harm from ingestion rests upon a theoretical basis. As Dr. Selikoff explained, there are several possible explanations for the increased evidence of gastrointestinal cancer, some of which do not involve ingestion. (A.11:41-43.) Moreover, as noted previously, the excess rates of gastrointestinal cancer are generally modest (A.10:220, 223, 226, 279.), and substantially lower than the excess rates of mesothelioma and lung cancer associated with inhalation of asbestos dust. Also, the experts advised that an analysis of a small exposed population may produce statistically unstable results. (A.10:278-80.) 105 The existence of an excess rate of gastrointestinal cancer among asbestos workers is a matter of concern. The theory that excess cancers may be attributed to the ingestion of asbestos fibers rests on a tenable medical hypothesis. Indeed, Dr. Selikoff testified that ingestion is the probable route accounting for the excess in gastrointestinal cancer. (A.11:44.) 47 The occupational studies support the proposition that the ingestion of asbestos fibers can result in harm to health. 106
107 The second primary uncertainty with respect to ingestion involves the attempt to assess whether the level of exposure from drinking water is hazardous. Of course, this inquiry is handicapped by the great variation in fiber counts, and Dr. Brown's admonition that only a qualitative, and not a quantitative, statement can be made about the presence of fibers. 48 108 In spite of these difficulties, the district court found that the level of exposure resulting from the drinking of Duluth water was comparable to that found to cause gastrointestinal cancer in asbestos workers. 380 F.Supp. at 48. The court drew this finding from an elaborate calculation by Dr. Nicholson in which he attempted to make a statistical comparison between the fibers probably ingested by an asbestos worker subject to an excess risk of gastrointestinal cancer with the probable number of amphibole fibers ingested by a Duluth resident over a period of 18 years. (A.22:228-229.) To make this calculation, Dr. Nicholson computed what he believed to be the level of exposure in a typical occupational environment and multiplied this figure by the total amount of air inhaled by the worker over a four-year period (taken to be the relevant period in which a risk of excess gastrointestinal cancer was posed), thereby obtaining total fibers inhaled. A percentage reduction was then applied to obtain the number of fibers brought up the respiratory tract and swallowed. For Duluth residents, Dr. Nicholson calculated the number of fibers ingested over an 18-year period, assuming a daily intake of two liters of water and a fiber concentration of 25 million fibers/liter. From these assumptions, Dr. Nicholson opined that a Duluth resident over a period of 18 years ingested about two-thirds of the amount of asbestos fibers swallowed by an asbestos worker in four years. As is evident, this calculation is beset by several uncertainties. The assumptions as to fiber concentration in occupational settings and the resulting percentage of fibers ingested involve margins of error. Furthermore, in assuming that the relevant fiber concentration in Duluth water was 25 million fibers/liter, Dr. Nicholson used a figure twice that found by the court as the mean concentration of all amphibole fibers. 49 Reserve witness Dr. Gross performed a calculation similar to Dr. Nicholson's, but using somewhat different assumptions, and concluded that Duluth water would have to contain several hundred million fibers/liter and be ingested for 60 years before an exposure comparable with occupational levels would be reached. (A.17:37-51.) 109 The comparison has other weaknesses, for without regard to the comparability of the gross exposure levels, the dynamics of the exposure process are markedly different. The vagaries attendant to the use of assumptions rather than facts result in comparisons which are of dubious accuracy. Thus, Dr. Brown testified that, if Nicholson's calculations were correct, he would conclude only that the risk was non-negligible. (Brown dep. at 20.) 110 The Nicholson comparison, although evidentially weak, must be considered with other evidence. The record does show that the ingestion of asbestos fibers poses some risk to health, but to an undetermined degree. Given these circumstances, Dr. Brown testified that the possibility of a future excess incidence of cancer attributable to the discharge cannot be ignored: 50    I would say that it is conceivable that gastrointestinal cancers can develop from the ingestion of asbestos, and what I don't know, Your Honor, is just how low that level of ingestion must be before the likelihood of GI cancer becomes so remote as to be, for all intents and purposes, ignored as a real live possibility. (A.23:157.) 111 We quote at length Dr. Brown's testimony expressing the medical concern appropriate to the continued discharge of asbestos fibers into Lake Superior: 112 (Dr. Brown). After some degree of exposure to the literature and to the testimony given in this trial I would say that the scientific evidence that I have seen is not complete in terms of allowing me to draw a conclusion one way or another concerning the problem of a public health hazard in the water in Lake Superior. 113 Q. (The court). Would you define the difference between what you say is scientific proof and medical proof, and then maybe I will give you another kind of proof that I have to live with here and we will see where we are going? A. Well, science requires a level of proof which is pretty high. That is, we do not accept as truth things that seem to be casually associated, a cause casually associated with an effect. We have erected certain statistical barriers which force us to come to conclusions based on probability, and Dr. Taylor used those terms. He used .05 per cent, he used things like .01 per cent, criteria which generally are accepted in the scientific community as levels which are consistent with or from which you can conclude that there is some cause and effect relationship. 114 Q. All right. Now, scientific proof for what purpose? Doesn't the quantum of proof vary with the purpose? Now, I haven't really asked you this before, but wouldn't scientists be satisfied for one purpose and not another, or is that when you stop and put on your medical hat then, after you get a certain quantum of proof? 115 A. Well, as a scientist, sir, I would say that there are many questions which have been raised in this trial which would provide me with a hypothesis which I would like to see pursued. This is in the abstract scientific sense of an interesting intellectual question for which there is suggestive evidence. 116 Now, when I turn, however, to the medical side of things, Your Honor, I am faced with the fact that I am convinced that asbestos fibers can cause cancer, I am faced with the fact that I have concluded that the size of the fibers is not particularly helpful in allowing me to decide whether a given fiber is or is not carcinogenic. 117 As a medical person, sir, I think that I have to err, if err I do, on the side of what is best for the greatest number. And having concluded or having come to the conclusions that I have given you, the carcinogenicity of asbestos, I can come to no conclusion, sir, other than that the fibers should not be present in the drinking water of the people of the North Shore. (A.23:202-203.) 118