Environmental controversies such as the Kishon River affair were beginning to grow prevalent around the world during the late twentieth century, and their resolution has proved to be a slippery problem that combines a fragile science with an anxious politics: a volatile mixture that has ignited many legal and policy debates since the 1970s (Schuck Reference Schuck1986; Huber Reference Huber1991; Beck Reference Beck1992; Jasanoff Reference Jasanoff1995; Tesh Reference Tesh2000; Fischer Reference Fischer2000). The Kishon River affair was no different. The scientists were well respected but were nevertheless incapable of settling the public agitation generated by the unfolding history of neglect and disregard for life and the river, and by the breakdown of trust between the military and its elite soldiers. Taking the Kishon River affair as a case study, this article follows the commission's jurist and scientists in their independent inquiries regarding causal connection. It then moves to analyze these inquiries within the larger context of the attempts of science and law to address the general global problem of toxic causation during the twentieth century. The result is a macro-history that recounts how the statistical science of epidemiology changed from playing an adjunct role to playing a vital and major role in the legal proof of toxic causation. It is also a micro-history that describes how different practices of evidence and proof can prevent science and the law from coming to an agreement in addressing toxic causation in cases like the Kishon affair.

Pollution

On May 25, 2000, Professor Avital Gasith, an aquatic ecologist from Tel Aviv University, took his students to conduct a field study along the lower part of the Kishon River, the largest and most polluted waterway in northern Israel (Shamgar Kishon Commission, Protocols, Jan. 10, 2001). Rising from the northern end of the Samaria Mountain ridge, the Kishon flows northwesterly for about 70 km. on its way to the Mediterranean Sea. It runs through the agricultural Jezreel Valley, draining runoff water heavy with fertilizers and pesticides from intensively cultivated fields. The river then cuts through the Haifa metropolitan area where it serves as a receptacle for waters that have gathered the ever-growing urban load generated by the burgeoning population. Finally, the Kishon rubs backs with Israel's largest industrial port, the Haifa Bay, with its dense cluster of heavy industries – shipyard, refineries, petrochemical plants, etc. – all discharging their toxic wastes directly into its watercourse.Footnote ¹

Running strong for centuries earlier, the Kishon might have been able to handle its share of this modern abundance and carry it to the open sea.Footnote ² But in 1953, the young State of Israel, desperate to quench the thirst of its quickly growing population and its agricultural-based economy, dammed the river's upper watershed in the Jezreel Valley and redirected its flow into an artificial lake, to be stored for irrigation during the long, dry summer seasons (Blass Reference Blass1967; Yaffe Reference Yaffe2000). The capture of the water at the head transformed the lower Kishon into a small stream with little capacity to carry the heavy agricultural, municipal, and industrial deposits into the sea. Hereafter, the river quickly deteriorated. By the 1960s, the mounting discharge had already surpassed the natural flow of the river and converted it into a sewage conduit, which was especially polluted in the summer months when natural flow was minimal.Footnote ³

By the 1970s, worried public health officials reported that the Kishon was “so heavily contaminated with industrial wastes that it wiped out any sign of biological life” (Avital Reference Avital1972, 1). A preliminary report of Balasha-Jalon Infrastructure Systems strongly warned against any direct human contact with its water (Balasha-Jalon 1975). By the 1980s, scientists from the National Oceanographic and Limnological Research Institute who monitored the river warned the authorities that the extensive toxic sedimentation was accumulating on the bottom of the Kishon River, slowly choking it and diminishing its capacity to channel its large flow into the sea (Hornung Reference Hornung1989; Hornung, Kress, and Krumgalz Reference Hornung, Kress and Krumgalz1990). By the early 1990s, these warnings materialized. In the stormy winter of 1992, the lower Kishon River overflowed, covering residential and industrial areas with thick toxic sludge and transporting massive quantities of it into Haifa Bay (Kishon River Authority Annual Report 2000, 90).

The flooding and its tremendous cleaning costs put new pressures on the political system to find a solution to the Kishon River's problems.Footnote ⁴ Consequently, in 1994, a new statutory entity, the Kishon River Authority, was created to administer the political, legal, scientific, and administrative efforts needed for its rehabilitation.Footnote ⁵ The new authority quickly found itself walking a fine line. The largely privatized industrial cluster situated at the river's estuary played a central role in Israel's economy and offered tremendous political resistance. The refineries provided crucial energy to Israel's rapidly growing modern economy; and the petrochemical industries were among Israel's major exporters, turning local minerals into much needed foreign currency. Any attempt to enforce regulative measures that would add to the cost of production was conceivably a threat not only to the viability of the plants but also to that of the region or even the nation at large. The plants provided livelihood to thousands of residents in the Haifa area, and they were backed by the Histadrut, Israel's powerful umbrella labor union, which controlled much of local politics. Facing resistance high and low, the Kishon Authority chose to act pragmatically. Its officers avoided confrontation, abstained from taking punitive actions against any of the big polluting plants, and sought instead to cultivate cooperation by ongoing negotiation.

All parties agreed from all sides of their mouths that a proper solution must be found. Unfortunately, such a solution necessitated great expenditure and the plants were reluctant to bear the financial burden alone, without significant help from the government, which was not forthcoming. The plants responded with delay and evasion, doing just enough to avoid sanction but never enough to fully comply. The stage was set for a long and intricate choreography of administrative courting and industrial procrastination that lasted throughout the 1990s (Weinthal and Parag Reference Weinthal and Parag2003; Shmueli and Ben Gal Reference Shmueli and Gal2003).

Scandal

How do you measure the health of a river? For decades, concerned Israeli scientists have taken samples of the Kishon River to be checked at the laboratory. They sampled its gloomy water, conducted physical and bacteriological analyses, calculated chemical and pathogenic concentrations, and reported their findings in scientific publications and administrative reports. Professor Gasith's field study in May 2000 along the lower part of the Kishon River was certainly part of this on-going scientific concern with the Kishon. Still, Gasith belonged to a new generation of scientists who considered the traditional laboratory tests to tell only part of the story. Physical samples, he noted, have no memory. The samples reflect the situation at the time of the sampling and one could not determine from them what the conditions were a week or a month earlier. A toxic spill could have occurred earlier and not been detected, although it may have severely affected aquatic life for a long time to come. Furthermore, although the rich cocktail of pathogens, carcinogens, and other toxins in the Kishon River was well documented, their concentrations varied widely and many of them often remained within the limits dictated by the relevant standards. Hence, officially, the water may have posed no probable danger. But Gasith suspected that even if each concentration of a toxin by itself was below the regulatory threshold, the synergic impact of so many toxins put together could be extremely dangerous (Shamgar Kishon Commission, Protocols, Jan. 10, 2001). Environmental scientists have long acknowledged the possibility of such synergism, but have not been able to reduce it to practical laboratory measurements. Consequently, a growing number of scientists, Gasith among them, began to substitute biological for physical monitoring – that is, they analyzed biological species and their abundance instead of chemical elements and their concentrations. The results, Gasith maintained, may be less quantifiable but more truthful (ibid.; Gafny, Goren, and Gasith Reference Gafny, Goren and Gasith2000).

Gasith set his 2000 field study of the Kishon River for late spring, when biological activity was at its peak. Unfortunately, the surveying students failed to find any sign of life higher than microbes in the water of the lower Kishon (Shamgar Kishon Commission, Protocols, Jan. 10, 2001). That might have shocked some of them but not their professor. At the request of the Kishon River Authority, Gasith had been monitoring the Kishon annually since 1996, and had grown accustomed to these unprecedented results. He had surveyed many Mediterranean coastal streams during his career, and no matter how heavily polluted they were, he always managed to find some forms of life above the unicellular level. Not in the Kishon, though. The lower Kishon, as he succinctly put it two years earlier, in 1998, was, “for all intents and purposes ‘sterile'” (ibid.; Gasith and Pargament Reference Gasith, Pargament and Shapira1998).

Gasith was soon proved wrong. On the morning of May 26, 2000, just a few hours after he and his students completed their fruitless search for life in the lower Kishon, he learned that there was one species that was tough enough and resourceful enough to withstand even the toxicity of the Kishon – the Israeli Naval Commando. Gasith, together with the entire stunned nation, learned of this in a special investigative report that appeared in the weekend edition of Yediot Aharonoth, Israel's most popular daily newspaper (Tal-Shir and Yechezkely Reference Tal-Shir and Yechezkely2000). The Naval Commando, the headlines screamed, an elite and highly secretive unit in the Israeli military, has been training in the Kishon's basin unbeknownst to the civil authorities since the 1940s. For decades the Navy had ignored all existing warnings and sent its young soldiers to train in the waters of the Kishon River. Consequently, many of these soldiers died or were still fighting various forms of cancer caused by the heavily polluted water, while the Navy, the military, and the government looked the other way, denying responsibility and ignoring the plight of the sick soldiers and the families of those who had already died (ibid.).

Asked later how he could have let his soldiers train in this nasty water, General Ami Ayalon, the highly decorated ex-commander of the Naval Commando, pointed out that even pollution may have its attractions. “The filthy water did not bother us,” he explained. “On the contrary, the filthier it was the better the preparation for the real thing” (Shamgar Kishon Commission, Protocols, Nov. 26, 2000, 4). Others answered in the same vein. The polluted river presented a formidable challenge that separated the men from the boys. It made every little thing that much more difficult. But then, the slogan written large on the commando's dining-room wall was “difficult in training, easy in war.” Hence, all these long years, despite the filth and the stench and despite all the warning signs erected along the shores, the Naval Commando continued to train and dive in the Kishon's basin. Going under, the young trainees did not smell the stench. Coming up, their officers sometimes made them fill up their fins and drink the filth as a disciplinary measure. Getting out of the water, they took long showers, trying to scrub the putrid grime from their skin. They were young and unshakable. Other dangers occupied their minds and none of them gave much thought to the potential risks lurking in this dark body of water (Shamgar Kishon Commission, Protocols, Dec. 29, 2000).

It was only years later, when some of the divers began to contract various illnesses, that they started to suspect that their problems were related to their training in the Kishon. The first to make the connection was Yuval Tamir, who retired from the navy as Lieutenant General, after a twenty-three year career during which he logged more than one thousand hours of diving in the Kishon estuary. In 1998, shortly after his retirement, Tamir was diagnosed with skin and colon cancers. Suspecting that his cancers were related to his diving in the Kishon, Tamir turned to his commanders and requested that the Navy finance his medical treatment (Tamir Reference Tamir2004). His suspicion was brushed aside and his request ignored, so Tamir began to discuss his concerns with his fellow commandos only to discover that quite of few of them have also been dealing with various cancers, and that close to ten of them had already died. Outraged, Tamir and his friends decided to organize and take action. They wanted the military to acknowledge the link between their diving and their health problems and to terminate all activities in the Kishon. They also demanded that the Defense Ministry take responsibility, finance their expensive medical treatments, and support the families of those who died. When the military and the Defense Ministry responded with delay and evasion, they decided to make their plea public (ibid.).

Speaking out, in public, against their unit was not an easy decision for the naval commandos. Over the years their unit had become an integral part of their identity. They gave it their very best and cherished it dearly. In many ways their unit functioned as their extended family, but in return it demanded unconditional loyalty and absolute commitment to secrecy. Still, as it became apparent to the commandos that the military was refusing to acknowledge its responsibilities, and that their unit continued to train in the Kishon, some of them felt free to break the code of silence and to take their story to the media (ibid.).

Military service constitutes a central unifying narrative within the otherwise highly-fractured Israeli society. All young Jewish (except ultra-orthodox) citizens are required to serve in the military, during which time they must follow orders, sometimes to the extent of risking their lives. In return, the State, by means of the Ministry of Defense, guarantees full care of them and their families in case of injury or death in the line of duty. Trust in the State and the military is at the core of this vital contract between the State, the soldiers and their families. The elite military units, the Naval Commando prime among them, embodied the very essence of this contract as their soldiers took the greatest risks and in return received society's highest regard. The notion therefore that this trust had been compromised, especially in the Naval Commando, mesmerized the media and they played it for all its worth (Ben Asher Reference Ben Asher2003).

A huge scandal erupted overnight and the Kishon River emerged from the obscurity of scientific journals and political backrooms into the forefront of Israeli society. Newspapers, radio stations, and TV channels dug out the long history of disregard and neglect in the Kishon, raced for the personal stories of the distressed soldiers and their families, and highlighted the military's refusal to take responsibility for the welfare of the country's most beloved soldiers. The politicians also came forward. The scandal became a hot topic in Israeli politics, and Yuval Tamir and his fellow commandos became personae gratae at the various meetings of parliamentary commissioners who were eager to share the spotlight (Parliamentary Commission on Internal Affairs, Protocol 2000; Parliamentary Commission on the Military Budget, Protocol 2000).

Commission of Inquiry

In response to the public outcry and political pressure, the Israeli Navy declared its intention to appoint a military commission of inquiry, headed by two ex chief-officers of the Military Health Corps, to investigate the connection between the polluted river and the incidence of cancer among the soldiers who dived in it (Tamir Reference Tamir2004). A military commission is considered “an instrument for the commander to identify malfunctions in the body under his direct command, in the chain of command, for the purpose of learning and improvement” (Military Law Reference Military1955). The military creates the commission, defines the scope and goals of the inquiry, and staffs it with officers and experts of choice. By law, the military is required to appoint such a commission in every military case that involves suspicious death or serious injury not directly related to war. It must be chaired by a military officer, and in cases that involve disease-related deaths it should also include at least two medical experts. The committee possesses significant powers of inquiry, including the authority to summon documents and examine witnesses, but it has no judicial powers of sanction and the evidence it adduces usually cannot be used in courts of law. Instead, the commission submits its report to the relevant military authority, which can do with it as it pleases (ibid.).

A broken trust is hard to mend, however, and the commandos, emboldened by the public and political support they were receiving, refused to cooperate with the suggested military commission. The Navy, they argued, could not and should not investigate itself in this case, and they threatened to appeal to the Supreme Court if it did (Tamir Reference Tamir2004). The ensuing days saw feverish negotiations among the parties. The Defense Ministry wanted to maintain close control over the inquiry, which could determine, inter alia, their liability for a potentially large number of soldiers exposed to a yet-to-be-defined spectrum of environmental risks, and insisted on a military committee. The commandos, who had lost faith in the military's good intentions, insisted on the appointment of a public commission, staffed with independent experts (ibid.). Such a commission is known in Israel as a Royal Commission.Footnote ⁶ The government orders the creation of a Royal Commission and defines its goals and scope. But the members of the Royal Commission are nominated by the president of the Supreme Court and the commission must be chaired by a senior judge, usually an active or retired member of the Supreme Court (Inquiry Committees Law 1968; Elman Reference Elman1971). This institutional framework integrated political, judicial, and scientific authority to gain wide public trust, and has played a significant role in negotiating some of Israel's deepest public crises (Klagsbald Reference Klagsbald2001; Segal Reference Segal1984; Zamir Reference Zamir1984).

A solution was finally found in a person everyone respected and trusted – Meir Shamgar, president emeritus of the Israeli Supreme Court and a towering moral and legal authority. Shamgar maintained long and close connections with the Army. During the 1960s, he served as Military Advocate General and was a key participant in the formulation of Israeli military law (Shamgar Reference Shamgar1982). Shamgar was also a revered civic icon. His public career was launched in 1968, when he was nominated Attorney-General of Israel, a role he gave meaning to by declaring war on corruption and inculcating awareness for the rule of law at all levels of government. In 1975 he was appointed Justice of the Supreme Court, and in 1983 became its president; a position he held for the next 13 years. During his long career at the helm Shamgar buttressed, in a series of high-profile decisions, the democratic norms in Israeli society – from the freedom of speech and press, to the rights of suspects and the accused. He also opened up the Supreme Court's portals to the public by expanding the right of appeal, and became a model for all justices for his respect and patience with the citizen standing before the bench. In short, he was loved and trusted by all – a tall order in the highly fractious Israeli society.Footnote ⁷

After his retirement in 1995, Shamgar was continually called upon by the private sector to arbitrate its thorniest financial disputes and by the political sector to sort out the most notorious public crises. After the 1995 assassination of Prime Minster Rabin by a religious extremist, Shamgar was the only consensual candidate trusted to chair the Royal Commission appointed to inquire into the assassination (Rabin's Assassination Commission 1996). Shamgar held unique status as a supreme mediator in Israeli society and the reader can imagine therefore the collective sigh of relief heard when Shamgar agreed to chair a military commission that would look into the Kishon affair. His presence resolved the debate over whether the people could put their trust in the Commission. The Ministry of Defense trusted the former Military Advocate General to have its interests close at heart, while the soldiers trusted that the president emeritus of the Israeli Supreme Court would represent them fairly in the face of what they conceived as official obtuseness (Tamir Reference Tamir2004). The Defense Ministry asserted its control over the Commission's business but the presence of Shamgar transformed the military committee's status, giving it moral weight and public visibility that the military and the government would find hard to ignore.

Choosing the scientific experts to sit next to Shamgar and assist him in the inquiry proved contentious as well. Various names were suggested by the military only to be turned down by the commandos for their alleged ties with the military, or the relevant industries and municipalities (ibid.). Finally, Shamgar was able to broker an agreement among the parties for two senior scientific figures to serve with him on the Commission: Professors Meir Wilchek, a highly regarded biochemist from the Weizmann Institute of Science, and Gad Rennert, a senior epidemiologist and expert on public health, from the Carmel Hospital in Haifa. Thus, with law and science secured at the helm, the door was now open for a legitimate resolution to this most agonizing conflict between the State and some of its most revered citizens.

The Commission at Work

On July 24, 2000, the Israeli Defense Forces’ Chief of Staff, General Shaul Mofaz, convened a press conference to announce the terms of the agreement. The Israeli Defense Authorities would appoint a Military Commission of Inquiry. Chaired by law and guided by science the commission was authorized to investigate the following four questions: 1) Has the water of the lower Kishon contained hazardous materials? 2) What are the potential medical risks for anyone trained there? 3) What is the causal connection between the waters and the various cancers discovered among the soldiers who trained in them? 4) What is the responsibility of the various military authorities? (Shamgar Kishon Commission, Protocols 2001, 13).

The Commission quickly set to work. Military commissions usually run their business behind closed doors but recognizing the public sensibilities involved, the Shamgar Commission decided to open its meetings to the public, except when national security or personal privacy dictated otherwise (ibid., Aug 1, 2000). Starting on August 1, the commission held within the next three months 27 meetings, 19 of them open to the public. During this period the Commission also toured the Kishon River area, both by foot and by boat; heard testimony from 103 witnesses; and reviewed more than 600 records that included scientific and technical reports, military orders and protocols, as well as minutes, reports, and other papers generated by various professional and political bodies that were involved with the Kishon River since the 1950s (ibid. 2001, 14–15).

It did not take long for the Commission to realize the scale of the calamity they were dealing with. The evidence that mounted left no doubt that the lower Kishon had been heavily polluted for many years and that the culprits included almost everyone involved: the industrial plants that took the river hostage and pumped their toxic wastes into it; the municipal authorities that did the same with their domestic sewage; the administrators and politicians who knew about the pollution but looked the other way; the arrogant naval commanders, who ignored all warnings and failed to guard the safety of their soldiers. It was therefore rather easy for the Commission to quickly answer two of the four queries it was charged with: Did the lower Kishon contain hazardous materials? Plenty. Who could be held responsible? Plenty, again. Nothing, however, was easy about the two other tasks before the commission: to estimate the medical risks emanating from the river and to negotiate from these a verdict regarding the causal connection between the water and the cancer.

The Commission decided to launch a comprehensive scientific study of the risks involved in diving in the lower Kishon. Such an endeavor necessitated massive administrative and medical efforts. All soldiers who had ever served in the relevant military units needed to be identified and summoned for an extensive series of questionnaires, interviews, and medical tests. Initial estimates talked about more than 5,000 such soldiers and it was clear that it would require considerable time for all of them to be properly tested. The Commission decided therefore not to wait for the completion of the entire study, but to go ahead and publish an interim report that would address the urgent needs of the sick soldiers and their families, as well as the immanent dangers of the Kishon that required immediate attention (ibid., 15).

The preliminary report was released in July 2001, a year after the Commission started its work. Recounting the long history of the river's pollution, the report spared no element involved: The polluting plants and municipalities, the inattentive regulators and licensing authorities, the careless politicians, the arrogant militant commanders and their medical officers – all were privy to this scandalous affair. All of them knew or should have known what was going on, and each of them could and should have taken action to stop it. Indeed, the Commission found the neglect to be so widespread and systematic that it saw no purpose in pointing fingers. The commission interim report grimly noted:

The preliminary report concluded with a set of recommendations, most of them directed at the military. These addressed three major issues. First, the sick soldiers and the families of those already deceased should receive interim medical and financial help pending the Commission's final resolution. Second, all military activities involving physical contact with its water must be suspended until the Kishon was rehabilitated. Third, the army should develop the capacity to test the environmental safety of all military training sites before soldiers be allowed to train there. Although not included in its mandate, the Commission members found themselves obliged to comment also on the disturbing state of public affairs they encountered during their investigation. The culture of disregard towards the environment must not be tolerated anymore, they proclaimed. The civil authorities must use the legal and technical means available to them to prevent further pollution of the Kishon with dangerous materials (ibid., 235–242).

The Commission's recommendations were not legally binding. Furthermore, they were preliminary in nature, as the inquiry was not complete and the final picture was far from clear. Nevertheless, the government officially adopted the recommendations of the preliminary report and instructed the ministries of Defense and Environment to implement them (Government meeting Protocol, Feb. 24, 2002). Consequently, the military appointed various professional teams to study the environmental safety of the extensive military training sites. Never before had an Israeli environmental research program had access to such political and financial resources; the result was an unprecedented database that mapped environmental risks over much of Israel (Rinat Reference Rinat2006; Almog and Amitai Reference Almog and Amitai2006). Meanwhile, all were waiting for the publication of the Commission's final report, and with it the resolution of the main bone of contention – what is the causal connection between the commandos’ cancers and the water they dived in?

Constructing Causality

Science offered the Commission two distinct modes of calculating risks and establishing causality, and Meir Shamgar made sure to have an expert in each mode seated next to him. Meir Wilchek, biochemist, represented the first modality – an experimental, reductionist science, built on the strength of the laboratory. Gad Rennert, epidemiologist, represented the second – an observational, statistical science built on the power of big numbers.

Earlier in the twentieth century it was the experimentalists who dominated the field and provided the kind of answers sought by the Commission. Toxicity was checked in the laboratory. One strategy, called in vitro studies, examined the effects of chemical agents on materials ranging from molecules such as DNA and proteins, to cells, bacteria, and even embryos, in order to better understand the biochemical mechanisms involved. Molecular structural analysis was also called upon to gain clues from structural resemblance of one chemical to other better known chemicals. It is a long way, however, from molecules to humans, and other researchers had taken a shortcut by performing in vivo studies. This reduced some of the difficulties but introduced new ones. Unable to experiment directly with humans, the toxicologists ran their studies on other mammals. But although much is common across mammalian species, much is also different, and scientists are not always sure which is which. In addition, in vivo studies typically involve larger-than-life doses, to shorten the experiment and augment its effects. Toxicologists turn to mathematical models, known as dose-response curves, to extrapolate from the short and intense exposure of the tested mammals to a chronic low-level exposure of humans. The model serves for the calculation of the risks per any given dose and any given period, and for the setting of exposure standards, with appropriate safety factors to protect the more susceptible subpopulations (McClellan Reference Roger1999).

During the 1970s, as environmental regulation took central stage in western polity, the power of this experimental science to provide answers good enough to legitimize administrative and legal action was closely scrutinized. As the young regulatory agencies began to churn out their safety standards, both industry and civil action groups challenged the science behind the standards – industry in an attempt to moderate the standards; activists, to step them up (Jasanoff Reference Jasanoff1995, 69–92). The ensuing legal battles revealed the fragility of the science involved. What had thrived in the temperate climate of the laboratory did not survive the adversarial heat of the courtroom. The notorious non-linearity of physiological systems was mobilized to undermine the extrapolations from high to low doses and from short to long exposures; and the poorly understood interspecies and intrahuman variations were called upon to show that the justification of the standards went beyond scientific and technical competence (Reserve Mining Co. v. Environmental Protection Agency 1975; Ethyl Corporation v. Environmental Protection Agency 1976). Eager to protect the regulatory regime, the legal system responded by adopting the powerful precautionary doctrine, which admitted the fragility of the science involved but nevertheless justified the right of the authorities to act upon it, based on the ever-pressing need to regulate potential risks before they turn into actual harm. The legitimacy of such a regulatory regime, the courts prescribed, resided in its deployment of the best scientific tools available. These tools, they also increasingly suggested, may no longer be found in the laboratory but in the arsenal of epidemiology (Rosenberg Reference Rosenberg1984; Weinstein Reference Weinstein1984).

Earlier in the twentieth century, epidemiology served public policy merely as a form of surveillance technology. Medical attention was focused mainly on infectious diseases – each caused, as it was generally held, by a specific microbiological agent.Footnote ⁸ Fighting infectious diseases was a job for the laboratory – to isolate the specific causal organism, study it, and devise the best means to fight back. Epidemiology served in this campaign by informing of geographical and social patterns of disease. But by the middle of the twentieth century, the balance had begun to shift. At least in the developed world the battle against infectious diseases seemed to have been won and public and medical attention increasingly turned to a new and rising pattern of disease – non-infectious, chronic, with long latency, and with poorly understood etiology, diseases such as cancer or heart diseases that began to top the medical charts. Experimental science, with its reductionist logic and specific causality model, made little headway with these new kinds of health problems. These problems seemed to have multiple, and often quite different, causes; their long latency made experimentation difficult, if not impossible, and their mechanisms kept eluding the researchers. Epidemiology, on the other hand, proved much more flexible. As a post-facto observational science that relates exposure to outcome, it did not have to ponder too much over the elusive biological mechanisms involved. Instead, epidemiologists adapted their computational strategies to a distributed, multivariate model of causation that seemed to better fit the nature of these new diseases, where a cause could have many effects and an effect many causes (Black and Lilienfeld Reference Black and Lilienfeld1984; Brannigan, Bier, and Berg Reference Brannigan, Bier and Berg1992).

The power of epidemiology to make causal claims in this new web-like universe of irreducible, chronic health problems was demonstrated during the late 1950s and early 1960s, when a cluster of British and American epidemiological studies first implicated cholesterol and smoking as significant causal factors for heart disease, and in the case of smoking, also for lung cancer (Dawber, Meadors, and Moore Reference Dawber, Meadors and Moore1951; Doll and Hill Reference Doll and Austin Bradford1950, Reference Doll and Austin Bradford1952, Reference Doll and Hill1954, Reference Doll and Hill1956). Running ahead of experimental research, these studies made no appeal to concrete biological mechanisms.Footnote ⁹ Instead, they introduced a new lexicon that appealed to what came to be known as “risk factors” – environmental, social, and other patterns that are statistically correlated with higher incidence of disease; the higher the correlation the more certain the association. Nevertheless, or precisely because of it, many medical scientists rose up in arms. At stake, they cautioned, was no less than the scientific essence of modern medicine, which was rooted in the laboratory. Epidemiology, they pointed out, was not an experimental science. It could neither control its data nor test the veracity of its conclusions. Thus, while epidemiology remained useful in generating causal hypotheses, only experimental science could reliably validate them (Fisher Reference Fisher1957; Feinstein Reference Feinstein1967, Reference Feinstein1973, Reference Feinstein1979, Reference Feinstein1988).

Criticism of this new-fangled epidemiology was by no means limited to die-hard experimentalists. Scientists committed to genetic views of disease faulted epidemiology for focusing attention on environmental effects, while those committed to social explanations of disease faulted it for focusing attention on individual factors abstracted from their social context. Perhaps the most sophisticated critiques came from bio-statisticians anxious to protect the integrity of their science from political pressures, and from epidemiologists who were concerned that too much would be claimed for their fledgling science, which was just starting to make inroads into medicine. These critics were able to point out various methodological difficulties inherent in epidemiological research, from sampling and selection biases to confounding variables, which further undermined epidemiology's capacity to establish authoritative causal claims (Brandt Reference Brandt1990; Marks, Rosenberg, and Jones Reference Marks, Rosenberg and Jones1997).

The proponents of the new risk-factors epidemiology responded by appealing to concrete usefulness rather than abstract truthfulness. They conceded that experimental demonstration of concrete causality constitutes a higher form of scientific proof, but pointed out that such a proof was hard to come by in this new era of chronic diseases. In the absence of such strong proof, they prescribed epistemological modesty and methodological flexibility. The distributed nature of the problem should be met with an equally distributed scientific effort. The epidemiologist's search for health risks was still to be based on the strength of carefully constructed statistical studies, but epidemiologists should remain mindful of the limitations of their method and careful to support it with other types of evidence. In the absence of a concrete demonstrable mechanism, the epidemiologists should nevertheless look for a plausible biological explanation. In the absence of direct experimental control, the epidemiologists should support their causal hypothesis by plausible temporal and dose-response curves, and indeed by any other coherent source of evidence. None of these explanatory factors was sufficient or necessary, nor could any of them bring forward indisputable evidence for or against the causal hypothesis. Epidemiologists should therefore qualify their confidence with appropriate confidence margins, and single studies should be treated skeptically until their results are verified by other studies, conducted by different persons, in various places, circumstances, and times. The combined weight of these studies, the epidemiologists maintained, was in a growing number of cases the best science could offer public health decision-makers in this new era of latent and irreducible causes and chronic disease (Hill Reference Hill1965; Gordis Reference Gordis1988).

Disdained by scientific purists, this pragmatic program of epidemiology was warmly embraced by the expanding regulatory regimes of the late twentieth century. Practical by nature, legislators, administrators, and public health officers were less concerned with the rigorous pursuit of experimental design and more with the pressing businesses of public policy, which often necessitated judgment made with less than perfect information (Surgeon General's Advisory Committee 1964). They found epidemiology with its quantified logic and its focus on the population as the unit of investigation perfectly placed to provide them with potent tools to estimate the prevalence of otherwise irreducible health problems, investigate their probable sources, identify those groups with elevated risks, and target them with preventive measures (Terris Reference Terris1987; Thacker and Berkelman Reference Thacker and Berkelman1988; Hertz-Picciotto Reference Hertz-Picciotto1995).

The latter part of the twentieth century therefore saw a flourishing of the so-called “black-box epidemiology” – a technical, policy-driven epidemiology that shunned biological hypotheses and concentrated on computing the risks facing taxpayers from a myriad of modern conditions (Pearce Reference Pearce1996). The parallel growth of medical registries and computer technology allowed for the deployment of increasingly complex statistical techniques in the search for increasingly smaller risks in increasingly larger populations. The epidemiologists traded up their mechanical rulers first for punch cards and then for software programs, and got comfortable with the new tools of multivariate correlation and regression, and exotic tests of statistical significance. By the end of the twentieth century, the reduction of causes to a distributed network of risk factors had become prevalent and increasingly informed medical research, as well as regulatory and legal action. In theory, some continued to insist, this was not a science of causation. In practice, however, it was exactly this – a hunt for causes; if not for science then certainly for administrative and legal action (Susser Reference Susser1985, Reference Susser1996).

The Scientific Side of Causality

Professor Wilchek belonged to the top tier of Israeli science. His contributions in the field of molecular recognition and their applications to biological systems had earned him wide international fame, and his expert advice was much sought after by a wide spectrum of clients, from regulative agencies to start-up biotech companies.Footnote ¹⁰ Yet, Wilchek's experimental expertise was not well suited to deal with the kind of problem posed before the Commission. Too many chemicals were out there in the Kishon River, and too little was known about most of them, not to mention their synergic effect. They came in different forms – soluble in the water and combined in the sediments; in suspended particles and in interstitial water; each form governed by many interlinked factors, such as acidity and temperature (Landis and Van der Schalie Reference Landis and Van der Schalie1990; Clescerl, Greenberg and Eaton Reference Clescerl, Greenberg and Eaton1998). Even if an adequate model could be constructed for this complex environment, Wilchek would still need to feed it with reliable input. Unfortunately, the commandos’ exposure to the Kishon River was intermittent, and spanned four decades during which the conditions at the river varied widely.

Thus, it was unlikely that accurate exposure information could be obtained. The ultimate dose intake further depended on the absorption rates of the various chemicals through the divers’ skin, lungs, and digestive tracts. Some of these rates had been studied but not all, and little was known about their behavior under diving conditions (Richter Reference Richter2003a, Reference Richter2003b; Amitai et al. Reference Amitai2003; Almog and Amitai Reference Almog and Amitai2006). Did wet-suits protect the divers or increase their risks? Did water pressure affect absorption rates? Add these uncertainties and others to the methodological problems facing experimental toxicologists, and we can see why Wilchek's contribution to the Commission's scientific inquiry into the causal relation between the water of the Kishon and the cancer contracted by the naval commandos was secondary at best. Instead, it was Dr. Gad Rennert, the epidemiologist, who took over the inquiry.

Epidemiology's principle strategy for studying causation in toxic cases is the so-called “cohort study.” In this study design, the researcher first identifies the exposed individuals and then compares their incidence of disease with that of another cohort, of unexposed people. The result is an attractive decision mechanism in the shape of simple index of relative risk, defined by the ratio of the disease incidences of the exposed (nominator) and unexposed (denominator) cohorts. The higher the index, the stronger the confidence that the computed association represents a causal relation. A relative risk of one signifies that the incidence rate is the same among the exposed and non-exposed cohorts and thus indicates a lack of association between the suspected exposure and the alleged disease. Relative risk greater then one suggests that exposed people are at a higher risk of disease than those who are not exposed. A relative risk greater than two indicates that the exposed more than doubled their chance to contract the disease. From a population perspective, this means that more than half of the exposed could attribute their disease to the exposure. From the individual's perspective, it means that the exposure was more likely than not responsible for his or her disease (Rothman and Sander Reference Rothman and Greenland1998, 79–93; Rochon et al. Reference Rochon2005, 330; Meirik and Case Control Studies).

The logic of the cohort study is sound. The devil is in the details. The compared cohorts need to be as similar as possible, except for the specific risk under study. The more similar the cohorts, the more epidemiologists can be certain that the correlations they compute could be assigned to the risk under study and not to other, unaccounted for, confounding factors. The standard is the so-called “clinical trial” – which compares incidence rates of health complications in various cohorts, each assigned with a different medical treatment. The comparability of the clinical trial's cohorts is assured by randomization, i.e. by assigning individuals to large cohorts via a random process. However, in toxic exposure cases such as the Kishon affair, the cohorts of exposed and non-exposed had already been set by the events of the exposure. In such cases the epidemiologist's first challenge is to accurately reconstruct these cohorts from personal and institutional memory – a task easier said then done (Green, Friedman, and Ordis Reference Green, Michal and Ordis1994; Smith Reference Smith2002).

Rennert launched his inquiry with a massive administrative effort to identify all those individuals whose records indicated possible exposure to the water of the Kishon during their military service. Altogether, over 10,000 people were identified (4,145 from the Naval Commando) and summoned for a comprehensive set of interviews and medical tests. A little more than 3,000 showed up (1,911 from the Naval Commando) and were carefully evaluated according to their degree of exposure and types of medical problems. Estimating the degree of exposure was by far the hardest part. The military records were incomplete, especially during the early decades of the State, and uncertainty could not be avoided. The whole process took a year-and-a-half to complete, during which 107 cases of cancer were identified, 19 of which had been unknown previously. The extensive testing was required to ensure that all medical problems were discovered and treated. Rennert, also, needed the database for his investigation, but he had to use it carefully. For example, he could not include in his study the new cases discovered by the Commission's medical tests, since this would bias the comparison against any control group that was not equally tested.Footnote ¹¹ To preserve the comparability of his cohorts, Rennert was therefore forced to use only those cases recorded by the National Cancer Registry, and since this registry had a three-year lag, Rennert was forced to ignore not only the new cases discovered by the Commission's inquiry but all cases diagnosed after the year 2000. Altogether, about a quarter of the cancer cases known to the Commission had to be excluded, leaving Rennert with 81 cases to work with (Shamgar Kishon Commission 2003, chap. 17, 469–481).

Rennert's initial plan was to compare cancer rates between the naval commandos who dived in the Kishon (hereafter, the Divers) and a control cohort made of soldiers from other elite units (hereafter, the Elites). Such a control cohort, Rennert assumed, would be the most similar to the naval commandos in age, physical condition, social variables, etc. However, during the long process of data collection Dr. Rennert realized that he had access to an even better control cohort. The Naval Commando's training course is long and extremely hard, and Rennert found out that a significant percentage from those who started the course dropped out before reaching the stage that involved diving in the Kishon. He decided to use these dropouts as his optimal control cohort (hereafter, the Dropouts). Finally, Dr. Rennert also used data from the national cancer registry to define a third control cohort – the general Israeli male population (hereafter, the General Population), which he used as a base reference for all his other comparative analyses (ibid.).

Equipped with his four cohorts – the Divers, the Elites, the Dropouts, and the General Population – Rennert was finally ready to launch his analysis. First, he tested whether the rate of cancer among the Divers was indeed higher than in the three control cohorts. He found the results equivocal. The rate of cancer among the Divers was higher than the average recorded in the General Population by a factor of 1.21, and higher still when compared to the Elites, whose rate, as expected from their top physical shape, was significantly lower than that of the General Population. However, the most important comparison – between the Divers and its closest control cohort, the Dropouts – found no difference in rate of disease (Shamgar Kishon Commission 2003, 485–492).

To explain this curious result, Rennert looked for confounding factors, i.e. other risk factors that could have confounded his analysis. He noticed that those who volunteered to the Naval Commando (i.e. both the Divers and the Dropouts) showed higher rates of skin cancer of the type generally associated with exposure to the sun. Rennert assumed therefore that those who volunteered to the Naval Commandos tended to spend more time at the beach or at sea, even before their recruitment, and were more exposed to the sun than the other two control cohorts. To test his hypothesis, Rennert omitted all skin cancer cases from his calculations. The result: all significant differences disappeared. Without the melanomas, no causal pattern could be found in the data. The rates of cancer between the Divers and all three control cohorts were more or less the same. If there were any cancer risks in the Kishon, the analysis failed so far to find them (Shamgar Kishon Commission 2003, 485–492).

Sensitivity is of constant concern in cohort studies. The design requires a large number of exposed individuals, since only a small fraction of them will contract the disease. The rarer the disease, the larger the cohort needs to be in order to discern its risk factors. The problem is further exacerbated in a case like the Kishon affair, where the exposure varied greatly over time in both content and intensity. In such cases, one could expect that any risk factor, if it existed, would affect only part of the cohort, during only parts of the exposure period, and be responsible for only part of all possible cancers. To look for such finer distinctions, the epidemiologist must further cut his cohorts in various ways. Like an anatomist, a good epidemiologist is judged not only by the soundness of his method but also by the quality of his cuts.

Such cuts carry their own risks, though. The more one cuts, the smaller the cohorts get; too small perhaps to reveal risk clusters in a statistically meaningful way. Moreover, the more one cuts and compares, the higher the probability of finding spurious differences, created by chance alone. This could lead to two types of error: either a false association could be found (false positive) or a true association could be overlooked (false negative).

Epidemiologists have always been more vigilant about the first type of error. To guard against the possibility of claiming associations that do not exist, they adopted a two-tier defense strategy termed the “null hypothesis.” This strategy operates under the presumption that no causal connection exists between the exposure and the disease under study, and demands a strong proof to reverse this presumption. Such proof requires not only the measurement of a high enough risk-ratio, but also the statistical assurance that it is not a false association, created by chance alone. Statistical theory can provide this assurance by calculating the probability of such false positives, and the epidemiological dogma demands it to be smaller than 5 per cent (i.e., less than 1 in 20) for the association to be considered statistically significant. This self-imposed standard reflects the cautious attitude of scientists who wish to be 95 per cent certain that their measurements are not spurious. But this caution comes with a price. The rates of false positives and negatives are inversely related. The less you allow for false positives, the more you are forced to allow for false negatives. In other words, the more you guard against false risks the more you are bound to miss true ones.Footnote ¹²

The evidence gathered by the Commission in 2000 made clear that the Kishon had steadily deteriorated since the 1950s. Still, until the early 1970s there was relatively little evidence of acute pollution, while reports from the mid-1970s forward started to specify significantly higher levels of pollutants in the water. This could have been an effect of better detection or better documentation rather than reflecting the degree of pollution in the water. Nevertheless, Rennert decided to use 1975 as a cut-off date. He divided each of his cohorts into two: those recruited before 1975 and those recruited after 1975. The finer grid provided a sharper picture. The cancer rate among the post-1975 Divers was now twice that of the post-1975 Dropouts, and 2.28 times higher than the cancer rate among the post-1975 Elites. And when Rennert eliminated the skin-cancer cases, the differences grew even stronger. Without the melanomas, the rate of cancer in the post-1975 Divers was 2.8 times higher than that measured in the General Population, and 2.4 times higher than the Elites (Shamgar Kishon Commission 2003, 485–494).

Rennert's higher resolution seemed to reveal some evidence that could support a causal relation between diving in the Kishon and contracting cancer. But the higher resolution came with a stiff price. The number of cohorts Rennert worked with was not a large number to begin with. Initially, 107 cases of cancers had been identified among the commandos. Of these, 31 were eliminated due to bias considerations. The remaining 76 cases were first divided into a Divers cohort of 39 and a Dropouts cohort of 37, and then again to Pre-1975 and Post-1975 sub-cohorts, the latter merely 12 cases strong. Add to this the relatively young age of the soldiers, and we can see how weak the statistical traction was. The cohorts were small, too small perhaps to provide the required level of statistical significance for anything less than really high risks.

Altogether, Dr. Rennert performed 73 comparisons and only seven of them proved statistically significant, and among these seven, only one pointed towards a clear risk – among the professional divers, a sub-cohort of the Divers, who spent significantly more time in the Kishon River than anybody else (ibid., 485–494).Footnote ¹³ All other correlations failed to rise to the level of statistical significance required by science and thus could not be formally interpreted as supporting evidence for the existence of a causal connection between diving in the Kishon and contracting cancer. Consequently, unable to discern a clear pattern of causation, Rennert felt obliged to stick with the null hypothesis. Science, he and Prof. Wilchek concluded, found no reason to reverse their initial working assumption that there is no causal connection between diving in the Kishon River and contracting cancer (ibid., 495–502).

The Legal Side of Causality

While the scientists on the Commission collected data and compared cohorts, their Chair, Chief-Justice emeritus of the Israeli Supreme Court Meir Shamgar, examined law books, collecting precedents and comparing legal opinion. The Commission's mandate was carefully limited to a factual determination of the causal connection between the Kishon River water and the commandos’ cancer. Yet, Shamgar had already made clear in the preliminary report that the inquiry into the causal connection could not be reduced to scientific evidence alone, for it had to be based on a more flexible and inclusive conception of causation. To explain, Shamgar differentiated three kinds of legal proof: direct and evident, statistical, and what he called “high probability.” Direct and evident proof, of the kind attainable by an eyewitness or experimental demonstration of cause and effect, was rarely available in cases of toxicity. In its absence, the law increasingly turned to the second kind of proof – statistical, of the kind attainable by epidemiology. But we should keep in mind, Shamgar insisted, that the third mode of proof, the so-called high probability, was also in play, all the more so when science was uncertain. Wider in scope and more flexible in application, high probability could resolve problems outside the reach of science. Made of multiple, often partial, pieces of evidence drawn from various sources and integrated by common sense, it was a dynamic mode of proof that could be reduced neither to science nor indeed to any single system of uniform proof. It was a mode of proof unique to legal culture, central to its identity and authority, and Shamgar busied himself considering its principles and their application to the problem before the Commission (Shamgar Kishon Commission 2001, 225–230).

Shamgar could not have found much in his legal library by way of direct local precedents. Israeli courts had considered the determination of toxic causation in individual tort cases but had never before ruled on a case like the Kishon affair, which crowded together a multitude of plaintiffs with various case histories, all claiming to be harmed by the same toxic exposure.Footnote ¹⁴ This was not the case in other countries, where fears of toxic exposure that might endanger a large number of people had become a trademark of late modernity (Beck Reference Beck1992). Courts in the United States, for example, had been struggling for at least four decades with cases concerning proof of toxic causation. The problem emerged in earnest in the 1970s in two main contexts: judicial review of regulatory action and private tort litigation, and in each context the courts responded differently. The judges put forward the precautionary doctrine to legitimize regulatory action in the absence of unequivocal science, but they were reluctant to extend the same leniency to the private sphere of litigation (Jasanoff Reference Jasanoff1995, 114–137). Claims of potential risk belonged to the public sphere and required a relatively low level of proof to justify regulative action. Anything more, the judges recognized, would leave but few environmental regulations standing. Claims of actual harm were treated differently, however. These belonged to the private sphere where, the courts insisted, the traditional requirements of tort law still held: the plaintiff must offer persuasive proof of concrete and actual harm caused by the defendant. Anything less, the judges held, would be unfair to the defendant, who should not be forced to pay for injuries it did not cause.

The courts’ insistence on concrete proof and the difficulties for science to deliver it turned causation into a central problem for the thriving late-modern genus of toxic tort litigation (Gold Reference Gold1986). Tort, the branch of private law that deals with injury claims, had traditionally prided itself on its individualized case-by-case approach. Its subject matter was willful human beings whose causal agency, the judges insisted, could not be subsumed mechanically, without the careful exercise of human judgment on a case-by-case basis (Holmes Reference Holmes1881; Horwitz Reference Horwitz and Kairys1992). Ironically, this humanistic approach was coupled with a model of causality as reductive as that of the science of infectious disease. To exist, a legal cause had to be reduced to a causal agent. To be sure, this causal agent was a human being, not a microbe, a fact that added a moral dimension and much complexity to the process of proof. Nevertheless, the plaintiff's burden of proof, like that of the medical experimentalist, was to single out this agent and demonstrate the causal chain of events that linked the agent's actions to the plaintiff's injury. If a specific causal agent could not be uniquely determined – that is, if the plaintiff could show only that the defendant's action might have caused the harm or if another indistinguishable potential cause existed – the courts usually dismissed the claim on account of failure to prove “specific causation” (Wright Reference Wright1985).

This reductionist model of specific causation has worked quite well in traditional tort cases such as accidents or assaults. The defendant's identity and conduct were usually verifiable by direct evidence such as eyewitness testimonies, and the causes for a black eye or a flooded house were understood well enough to allow the courts to decide liability based on whether those causes were controlled by the defendant. That was not the case, however, in a growing range of environmental, work-safety, and product-liability cases that came to be known by the end of the 1970s as “toxic tort” cases (Blomquist Reference Blomquist1992). These cases involved injuries of a kind that has frustrated experimental science – chronic injuries, with long latency and poorly understood etiology – injuries that could not be comfortably reduced to a single cause. In the absence of direct proof of cause and effect the courts increasingly turned to epidemiological evidence for resolution. That was particularly true for the new and emerging phenomenon of mass toxic tort litigation that clustered together large crowds with various case histories, all claiming to be harmed by the same exposure or by the same standardized, mass-marketed product. Here, lawyers and judges, just like legislators, administrators, and public health officers, found epidemiology's quantified logic and population-based analysis particularly conducive to their needs (Schuck Reference Schuck1986, 26–28).

Toxic Tort Litigation in the United States

Shamgar's Decision

Like his American colleague, Jack Weinstein, Chief-Justice Meir Shamgar also seemed determined to prevent the clearly negligent military and government from escaping its responsibility over the difficulties of proving causation in toxic exposure cases. However, Shamgar was chairing a military investigation commission, not a tort action, and thus was not obliged to reckon with tort's restrictive doctrine of causation. This allowed him to tackle the problem of toxic causation from a different legal angle which provided a safer rationale for allowing the ailing soldiers and their families to receive compensation and due recognition despite the lack of an adequate scientific proof.

Since its establishment in 1948, Israel developed an extensive body of law that deals with the rights of soldiers injured over the course of their military service. If recognized as Disabled Veterans, such soldiers and their families are entitled to generous compensation from the State by means of an extensive array of pensions, tax breaks, and other compensatory measurements. In order to be recognized as a Disabled Veteran, an injured soldier must prove that his or her injury was caused or aggravated by his or her military service. Families of soldiers who died while serving in the military are exempt from this requirement. In these cases, the courts have presumed a causal connection between the death and the military service and shifted the burden of proof to the military in the event that it wished to claim otherwise (Fallen Soldiers’ Families 1989). It was not enough for the military to merely show that the scientific evidence does not support causation. It had to provide specific proof that the soldier's death was not caused by his or her military service. The Israeli Supreme Court offered two primary reasons for this shift of the burden of proof. First was the legislators’ desire to compensate the families of deceased soldiers, even when the cause of death could not be clearly established. Second, while injured soldiers could provide direct details about the events leading to their injuries, the families of dead soldiers were at a distinct disadvantage vis-à-vis the military authorities regarding the collection of evidence (Payment Officer vs. Fruma Hecht 1985).

The legal presumption of a causal connection applied only to those soldiers who died during their military service. Those merely injured, or the families of those who died after their military service, were not exempt from proving the causal connection between their injury and their military service, and their proof was measured by the same preponderance-of-the-evidence standard used in tort. Still, Shamgar was able to assemble a body of precedents to show that even in such cases, when the soldier's proof of causation was frustrated by inconclusive medical opinion, Israeli courts had found various ways to ease the soldier's burden of proof (Shamgar Kishon Commission 2003, 507–528). Typically, the courts did not insist on the exclusion of alternative causal explanations for the injury. Instead, they allowed the soldier to show only a probable possibility of a causal connection between the injury at issue and the soldier's military service. Once the soldier had done so, the court shifted the burden of proof to the military to prove otherwise. If the military failed to do so, the court felt free to adopt the soldier's version over all other possible explanation. Shamgar quoted the following Israeli Supreme Court's justification for this leniency:

Next, Shamgar moved to examine the judicial treatment of causation also in civil toxic tort cases. This, he emphasized, was done only for comparative purposes. The relevant body of law remains that which dealt with the rights of soldiers injured during or because of their military service. Still, Shamgar was able to present a coherent body of precedents to show that in civil tort too, in cases in which the defendant's conduct was manifestly tortuous but the plaintiff had no means of identifying the specific cause of injury, Israeli courts had taken steps to ease the plaintiff's burden of proof by shifting some of it to the defendant (ibid., 530–575).

Having clarified the relevant legal principles and precedents of toxic causation, Shamgar finally turned to examine the actual question before the Commission – the determination of the causal connection between the water of the Kishon and the divers’ cancers. He first addressed the water. The evidence left no doubt, he concluded, that the water had been heavily polluted for decades by all kinds of carcinogenic materials. Next, he turned to examine the question of exposure. Here too, he concluded that the evidence made clear that the divers spent long hours in the water, coping with insufficient equipment, accidents, and disciplinary measures that increased their exposure to the dangerous water. Was that enough to deduce a causal connection? Shamgar did not ignore the negative conclusion of his scientific colleagues on the Commission. Instead, in an impressive display of rhetoric he presented Dr. Rennert's epidemiological study as an excellent scientific effort that was frustrated by unreliable exposure data and limited-size cohorts, which prevented it from providing an authoritative answer to the question before the Commission (ibid., 599–603).

Having established the difference between lack of proof of causation and proof of lack of causation, Shamgar referred back to the precedents collected. He showed that in similar instances Israeli courts tended to side with the injured soldiers’ causal version, if probable enough. Was that the case also with the Kishon River? Shamgar reviewed the testimonies of the epidemiological and medical experts who argued favorably before the Commission for such a causal connection (ibid., 593–597).Footnote ¹⁷ These testimonies may have carried less weight than the opinion of the Commission's own scientific experts, which was based on a direct study of the divers. Still, Shamgar argued, these testimonies, together with the evidence of the military's tortuous conduct and the divers’ exposure to the clearly dangerous waters of the Kishon River, were enough to make the divers’ causal version possible, if not probable. Consequently, Shamgar concluded, the evidence collected by the Commission justified the legal determination of a causal connection between diving in the Kishon River and contracting cancer (ibid., 605–606). In so deciding, it was important for Shamgar to clarify that he was not trying to second guess his scientific colleagues in their own expertise. Instead, he was motivated by legal considerations – namely, to protect the crucial social contract between the State, its soldiers and their families, and to abide by the legislator's explicit purpose to help those who took special risks for their country (ibid., 519–520).

The Final Report

The Commission presented its final report and recommendations to the Ministry of Defense in April 22, 2003, nearly three years in the making. The report was comprised of three parts that reflected the sharp divide among the members of the Commission. The first part of the report belonged to science. In it Gad Rennert described the principles and methods that directed his study, reviewed the data his team collected, tabulated the numbers computed, and explained the considerations that led him and Professor Wilchek to finally reject the hypothesis supporting a causal connection (ibid., 469–502).

The second part of the report belonged to law. Shamgar explained the legal principles that directed his analysis, reviewed the evidence regarding the long neglect in the Kishon, presented the precedents his team collected, and explained the considerations that led him to accept the causal hypothesis rejected by science (ibid., 503–606). By themselves, each of these two parts contained a masterful exposition of scientific and legal expertise. Together, bound in an official pale-blue cover that displayed the Menora, the ancient symbol of the modern State of Israel, they embodied the failure of science and law to come to terms in addressing the growing late-modern concerns with toxic exposure.

The third and final part of the report, which contained the commission's final conclusions and recommendations, failed to bridge the divide among the members of the Commission. With agreement beyond their reach, the scientists and the jurist chose to present their opposing conclusions in two separate sections. Rennert's and Wilchek's joint conclusion reflected the conflicts inherent in their position as scientists appointed to resolve an intense public controversy. Science, they reiterated, “did not prove that the pollution in the Kishon River caused a statistically-significant increase of cancer among the divers” (ibid., 608). Still, Rennert and Wilchek acknowledged the limitation of the science and the well-documented presence of carcinogens in the Kishon, and qualified their final conclusion. They noted that a statistically-significant increase of cancer was found among the sub-cohort of the post-1975 professional divers, who spent significantly more time in the Kishon River than anybody else, and recommended that the military recognize those “heavy divers” (as they called them) who contracted cancer as Disabled Veterans, making them eligible for compensation. Finally, and most unscientifically, they recommended that the military make an exception and accept responsibility, although perhaps on a lower level, for all other “lighter” divers who trained in the Kishon River and contracted cancer, because science “could not exclude the possibility of a causal connection between their exposure and disease” (ibid., 608).

Shamgar's conclusion was more clear-cut and authoritative. “In light of the concrete circumstances before us and the questions associated with the epidemiological study,” he wrote, “the Commission Chair sees no reason to join the Commission's majority opinion, which rejects causal, legal and logical connection” (ibid., 607). He recommended that each and every soldier exposed during their service to the Kishon and who contracted cancer should be duly recognized as an Israel Defense Forces’ Disabled Veteran and receive all compensation and support to which they were entitled by law (ibid., 607–608).

The failure of science and law to speak in one voice and present a unified consensual solution to the twin-questions of causation and responsibility prevented the resolution of the painful conflict between the military and its elite soldiers. Instead, the publication of the Commission's ambiguous final report generated a renewed swell of public outcry. The divers organized a press conference in which they and their experts angrily rejected the scientific findings of the Commission, criticized the slippery distinction between “heavy” and “light” divers, and demanded that the Ministry of Defense choose people and numbers. The newspaper headlines cried “Humiliation to the Divers,” and prominent public figures, generals, and members from all sides of the Israel Parliament joined the clamor and urged the government to adopt Shamgar's minority opinion and recognize each and every sick diver as a Disabled Veteran. “There is only one decision that the defense minister, Shaul Mofaz, can and ought to make in order to bring this tragic affair to conclusion,” wrote Yediot Aharonoth, Israel's largest circulating newspaper, whose investigative report had started the whole affair three years before, “and that is to recognize all sick divers as Disabled Veterans. It is the only moral and just resolution that he can take. There is no other. Not for the person who heads the organization that send these men to the water” (Yediot Aharonoth, April 22, 2003, 1; Maariv, April 22, 2003, 1; Kremnitzer Reference Kremnitzer2003).

The heated rhetoric left little room for any serious analysis of the intricate report.Footnote ¹⁸ The scientific view of the Commission was portrayed as petty, mean, and narrow, and was contrasted with Shamgar's “courageous decision that preferred the moral over the scientific, people over statistics; common sense over numerical hodgepodge” (Yediot Aharonoth, April 22, 2003). All this left the politicians with little choice. Five days after the publication of the report, the Minister of Defense Mofaz declared that the government reviewed the Commission's report and decided to embrace Shamgar's minority opinion. All the sick divers and their families, he promised the agitated public, will be taken care of (Government meeting. protocol. Apr 27, 2003; Moset Reference Moset2003).

This, everyone seemed to agree, was the only sensible resolution to the scandal. In the absence of an agreement between science and law, the politicians stepped in and exercised their legitimate power to restore justice, if not truth. But the sticky differences between science and law and between prudence and certainty refused to go away. At the time of Mofaz's ministerial promise, the number of soldiers seeking compensation was just several dozen. Since then, in compliance with recommendations of the Shamgar Commission, the naval commandos have been regularly monitored and more and more of them were diagnosed with cancer. By 2008, attorneys representing the veterans and their families estimated the number of soldiers who are attributing their cancer to their training in the Kishon River grew close to five hundred (Spira Reference Spira2008).

As the number of claims continued to grow, the Defense Ministry tried to scale down its original commitments and set new parameters that would limit the range of future suits. The Ministry announced that it will not recognize claims from anyone who trained in the Kishon River prior to 1975, and refused to accept claims from veterans who suffer from illnesses other then cancer, or served in other units, who were also exposed to the water of the Kishon River during their training. By 2008, the Defense Ministry had acknowledged only about half of the standing claims (ibid.). The Kishon affair continues to smolder then, and the relatively young age of the soldiers, and the long latency of cancer, virtually guarantee that it will not go away anytime soon. Like the toxic sludge that still lies under the lazy façade of the river, the Kishon affair had erupted violently onto the public surface only to sink back to the privacy of the dark bottom where it still lies until it is stirred up again.