`CERTIFIED FOR PUBLICATION
`
`IN THE COURT OF APPEAL OF THE STATE OF CALIFORNIA
`
`FIRST APPELLATE DISTRICT
`
`DIVISION TWO
`
`
`
`ALBERTA PILLIOD et al.,
`
`Plaintiffs and Appellants,
`
`
`
`v.
`
`MONSANTO COMPANY,
`
`Defendant and Appellant.
`
`
`
` A158228
`
` (Alameda County
` Super. Ct. No. RG17862702)
`
`
`
`
`
`
`
`
`After years of spraying Roundup herbicide on their property, Alberta
`
`Pilliod and her husband, Alva Pilliod, each developed non-Hodgkin’s
`
`lymphoma. The Pilliods sued Monsanto Company, the manufacturer of
`
`Roundup, for damages based on claims of design defect and failure to warn.
`
`After a six-week trial, the jury found for the Pilliods, awarded Alberta over
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`$37 million in compensatory damages, awarded Alva over $18 million in
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`compensatory damages, and awarded each of them $1 billion in punitive
`
`damages. The trial court conditionally denied Monsanto’s motion for new
`
`trial, contingent on the Pilliods’ acceptance of substantially reduced
`
`compensatory and punitive damages, resulting in a total award to Alberta of
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`about $56 million (including about $45 million in punitive damages) and a
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`total award to Alva of about $31 million (including about $25 million in
`
`punitive damages). The Pilliods accepted the reductions.
`
`
`
`On appeal, Monsanto argues that the Pilliods’ claims are preempted by
`
`federal law, the jury’s liability findings are not supported by substantial
`
`
`
`1
`
`
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`evidence, the jury was improperly instructed as to the Pilliods’ design defect
`
`claim, the jury’s causation findings are legally and factually flawed, the trial
`
`court abused its discretion by admitting certain evidence, and the verdict is
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`the product of attorney misconduct. Monsanto also argues that the punitive
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`damages awards should be stricken or further reduced because they are
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`unsupported by evidence and constitutionally excessive. In their cross-
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`appeal, the Pilliods argue that the trial court erred in reducing the jury’s
`
`awards for compensatory and punitive damages. We shall affirm.
`
`FACTUAL AND PROCEDURAL BACKGROUND
`
`
`
`We summarize the facts and evidence in the light most favorable to the
`
`judgment. (Cassim v. Allstate Ins. (2004) 33 Cal.4th 780, 787 (Cassim).)
`
`A. Roundup Herbicide
`
`
`
`Monsanto manufactures Roundup products, which contain glyphosate,
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`an herbicide that kills grasses and broadleaf plants. Glyphosate, the most
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`commonly used herbicide around the world, acts systemically: it is absorbed
`
`by the plant, travels to the root, and kills the plant at the root so it will not
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`grow back. The United States Environmental Protection Agency (EPA)
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`evaluates the safety of herbicides and determines whether they can be sold in
`
`this country. Monsanto has had approval from EPA to sell glyphosate-based
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`herbicides since 1974.
`
`
`
`In order to obtain that approval, Monsanto provided EPA with the
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`results of studies that examined the effects of glyphosate on animals,
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`including cancer studies conducted on animals by Industrial Bio-Test
`
`Laboratories (IBT). The studies were later found to be invalid, and Monsanto
`
`eventually repeated them in accordance with EPA guidelines.1
`
`
`1 Further information about IBT and Monsanto’s response to the
`invalidity of the studies appears below in section E of the Discussion.
`
`
`
`2
`
`
`
`
`
`In 1985, an EPA panel classified glyphosate as a possible human
`
`carcinogen, based on a 1983 study in which glyphosate produced a dose-
`
`related increase in rare kidney tumors and malignant lymphomas in mice
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`(1983 Study).
`
`
`
`In 1991, EPA reclassified glyphosate as a substance for which there is
`
`“evidence of non-carcinogenicity for humans,” on the basis of a “lack of
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`convincing carcinogenicity evidence in adequate studies in two animal
`
`species.” The reclassification notice emphasized that the designation “should
`
`not be interpreted as a definitive conclusion that the agent will not be a
`
`carcinogen under any circumstances.” The 1991 reclassification remained in
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`effect through the time of trial.
`
`
`
`In the decades since EPA first approved the sale of glyphosate-based
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`herbicide, glyphosate and Roundup have been extensively studied. Three
`
`types of data are widely accepted as being relevant to determine whether a
`
`substance causes cancer: human cancer data (the realm of epidemiology,
`
`which studies human populations to understand the causes of disease),
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`experimental animal data, and mechanism data. Mechanism data includes
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`studies of how a substance is absorbed and metabolized, as well as studies of
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`genotoxicity and oxidative stress.2
`
`
`
`In 2015, a “working group” of 17 scientists, convened by the
`
`International Agency for Research on Cancer (IARC), determined that
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`Roundup and glyphosate are probably carcinogenic to humans, based on the
`
`group’s review of published human cancer data, experimental animal data,
`
`
`2 Genotoxicity refers to damage to a cell’s DNA. Such damage can
`cause mutations in DNA, which can lead to cancer. Oxidative stress occurs
`when cells generate free oxygen radicals, which can bind to DNA, leading to
`genotoxicity.
`
`
`
`3
`
`
`
`and mechanism data.3 The IARC is part of the World Health Organization.
`
`One of the Pilliods’ experts characterized the IARC as “the worldwide
`
`authority on establishing whether an agent is a carcinogen.” One of
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`Monsanto’s experts, whose textbook on cancer epidemiology cites the IARC
`
`hundreds of times, declined to go that far, but conceded that the IARC is “one
`
`of the important cancer agencies.” The methodology used by the IARC to
`
`assess causality is widely used and accepted by scientists around the world.
`
`
`
`Although the IARC’s determination, issued in 2015, postdates the
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`period of the Pilliods’ most extensive use of Roundup (1982 through 2011),
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`data that was cited and relied upon by the IARC was available to Monsanto
`
`as long ago as 1980.
`
`
`
`As a result of the IARC’s classification of glyphosate as a “probable
`
`human carcinogen,” glyphosate is listed as a substance known to the State of
`
`California to cause cancer under Proposition 65 (Health & Saf. Code,
`
`§§ 25249.5–25249.13). Monsanto presented evidence that since the IARC
`
`announced its classification, numerous regulatory agencies around the world
`
`have concluded that glyphosate is not carcinogenic or is not likely to be
`
`carcinogenic. In particular, in September 2016, EPA’s Office of Pesticide
`
`Programs reviewed and evaluated over 120 epidemiological, animal
`
`carcinogenicity, and genotoxicity studies of glyphosate and concluded that
`
`“the available data and weight-of-evidence” support the statement that
`
`
`3 Monsanto emphasizes that the IARC conducted a “hazard
`assessment,” which determines whether a substance has the potential to
`cause cancer at some dose, and not a “risk assessment,” which considers
`whether the level of exposure to humans causes harm. The Pilliods
`emphasize that the IARC assessment was based on epidemiology data
`indicating that at real-world exposure levels, Roundup formulations cause
`non-Hodgkin’s lymphoma.
`
`
`
`4
`
`
`
`glyphosate is “ ‘not likely to be carcinogenic to humans’ at doses relevant to
`
`human health risk assessment.”4
`
`
`
`But in 2017, a Scientific Advisory Panel of independent scientists that
`
`EPA had asked to review its assessment of glyphosate issued a report
`
`concluding that EPA’s 2016 evaluation failed to follow EPA’s own guidelines
`
`in several ways. Further, according to the Panel’s report, though “some
`
`Panel members agreed with the characterization of glyphosate as “not likely
`
`to be carcinogenic to humans,” other Panel members felt that a better
`
`characterization would be “suggestive evidence of carcinogenic potential.”
`
`And “many Panelists noted that crucial data were equivocal, and that
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`additional date on cancer morbidity and/or mortality from studies of
`
`glyphosate-exposed workers would be desirable.”
`
`
`
`Glyphosate is not the only ingredient in Roundup, and testimony at the
`
`trial was not limited to glyphosate. Roundup also contains a surfactant,
`
`which enhances the absorption of the herbicide through the waxy surface of a
`
`plant.5 The surfactant also enhances the absorption of the herbicide through
`
`skin.6
`
`
`4 The office noted, however, that “due to conflicting results and various
`limitations identified in [epidemiological] studies investigating [non-
`Hodgkin’s lymphoma], a conclusion regarding the association between
`glyphosate exposure and risk of [non-Hodgkin’s lymphoma] cannot be
`determined based on the available data.”
`
`5 Roundup also contains water; small amounts of formulating
`ingredients, such as coloring and foaming agents; and trace amounts of
`contaminants that are known to be carcinogenic.
`
`6 EPA is concerned with the cancer-causing potential of glyphosate
`alone, rather than glyphosate-based pesticide formulations. In this respect
`the approach taken by EPA differs from that taken by the IARC. EPA’s
`Scientific Advisory Panel pointed out, however, that epidemiologic studies of
`
`
`
`
`5
`
`
`
`
`
`The surfactant used in Roundup in the United States, polyethoxylated
`
`tallow amine (POEA), is banned in Europe, where a less toxic surfactant is
`
`used. Roundup is much more toxic and genotoxic than glyphosate. Since the
`
`1990’s, scientists have warned that POEA appeared to make Roundup more
`
`toxic and genotoxic than glyphosate alone. In 2010, when discussion was
`
`beginning about banning POEA in Europe, Dr. William Heydens, Monsanto’s
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`“product safety assessment strategy lead,” wrote in an email that Monsanto
`
`should defend the use of POEA even as it was being phased out because of
`
`concern that a ban on the substance would lead to a “domino effect” in other
`
`parts of the world. Dr. Heydens wrote in a 2015 email that Monsanto
`
`believed that “the surfactant in the formulation . . . played a role” in a tumor
`
`promotion study.
`
`
`
`In an internal email written in 2003, Dr. Donna Farmer, a senior
`
`toxicologist at Monsanto, wrote that Monsanto could not say that Roundup is
`
`not a carcinogen, because it had not done the necessary testing on the
`
`formulation to make the statement, but Monsanto could say that glyphosate
`
`is not a carcinogen and infer that there is no reason to believe Roundup
`
`would cause cancer. Monsanto admits that it never conducted a long-term
`
`animal carcinogenicity study on any of the glyphosate-containing
`
`formulations that it sold in the United States. Dr. Michael Koch, a Monsanto
`
`employee who works as a regulatory toxicologist, testified in January 2019
`
`that there was no need to conduct such a study because glyphosate has been
`
`studied at higher concentrations than exist in Roundup and because “the
`
`safety dataset from the other components . . . has been found to show no
`
`safety concerns.” But in addition to the 1983 Study (which showed that
`
`
`glyphosate necessarily consider people who make or use glyphosate-based
`formulations.
`
`
`
`6
`
`
`
`glyphosate induced increased rates of rare kidney tumors and malignant
`
`lymphomas in mice), animal studies on glyphosate that were published in
`
`1993, 1997, 1999, 2001 and 2009 showed increases in lymphoma and/or
`
`kidney tumors. And a 2010 study showed that Roundup applied to the skin
`
`of mice promoted tumors.
`
`B. Plaintiffs’ Cancer Diagnoses
`
`
`
`In June 2011, at the age of 69, Alva was diagnosed with diffuse large B-
`
`cell lymphoma, stage IV, which manifested in his bones.7 This type of
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`lymphoma is a common type of non-Hodgkin’s lymphoma and is considered
`
`an aggressive cancer. In April 2015, at about age 70, Alberta was also
`
`diagnosed with diffuse large B-cell lymphoma; her cancer manifested in her
`
`central nervous system.
`
`
`
`For years, the Pilliods had used Roundup to kill weeds on four
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`residential properties. They started spraying Roundup at their primary
`
`residence in 1982. Alberta estimated that they sprayed about a gallon of
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`Roundup on that property each week, nine months per year, until 2011. They
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`also sprayed Roundup at three other properties throughout the years.
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`Alberta estimated that at one of the three, they used two gallons each week,
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`nine months per year, for two years; at another they used one gallon per
`
`month, nine months per year, for 10 years; and at a third, which they owned
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`for two years, they used a total of about nine gallons. Alberta estimated that
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`she did about 25 percent of the spraying and her husband did 75 percent.
`
`
`
`The Pilliods used both premixed Roundup and concentrated Roundup,
`
`which Alva would mix with water in a sprayer. Alberta estimated that they
`
`used the concentrate about 20 percent of the time. When Alberta sprayed
`
`
`7 Lymphoma is a cancer of lymphocytes, white blood cells that are part
`of the immune system.
`
`
`
`7
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`
`
`Roundup, there would be a mist in the air, which got on her hands. When
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`Roundup got on her skin, she did not wash it off right away, because she
`
`believed it was safe. The Pilliods worked in their yard together, so
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`occasionally if one was spraying Roundup, the other would encounter the
`
`mist. Alberta normally wore flip-flops, shorts, and a tank top or T-shirt when
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`she was spraying Roundup. Alva, who was concerned about exposure to the
`
`sun, often wore tennis shoes, long pants, long-sleeved shirts, a hat, and
`
`sometimes gloves. Roundup would sometimes spill on Alva’s hands when he
`
`was mixing concentrate and water. He rarely wore gloves when mixing
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`concentrate, explaining that he believed “[t]here was no need to,” and that
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`“it’s easier controlling all this stuff without gloves on.” When he was
`
`spraying Roundup, Alva did not usually wear gloves; Roundup would “run
`
`down on [his] hands” and would sometimes get on his feet when he sprayed
`
`it.
`
`
`
`Alberta testified that her belief that Roundup was “really safe to use”
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`was based on commercials she saw on television, in which people were
`
`depicted spraying Roundup in shorts and without gloves. She told her
`
`husband “it was like sugar water.” She testified that she read the Roundup
`
`label, which said nothing about wearing a mask or gloves when using it, or
`
`that users should not wear shorts or sandals, or any warning about the risk
`
`of cancer. She also testified that if Monsanto had warned of a risk of cancer
`
`associated with Roundup, she would not have used it.
`
`
`
`Alva testified that when he first started using Roundup, he read the
`
`label to see if there were any precautions, and saw nothing about wearing
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`gloves or protective gear, and nothing about cancer.
`
`
`
`Alberta testified that her husband stopped using Roundup at their
`
`primary residence in about 2011, after he became ill and “too weakened to
`
`
`
`8
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`
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`use it,” but before he was diagnosed with non-Hodgkin’s lymphoma. She
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`continued using Roundup after her husband was diagnosed with non-
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`Hodgkin’s lymphoma until she became sick in 2015, but “not as much.” Alva
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`testified that he stopped using Roundup in late 2016, when he read articles
`
`about Roundup causing non-Hodgkin’s lymphoma. Since they stopped using
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`Roundup, the Pilliods have used a spray of salt and vinegar to kill weeds.
`
`
`
`
`
`1. Alva’s Diagnosis and Treatment
`
`By 2011, Alva had retired. Over the course of his life, he had suffered
`
`some bouts of illness, but whenever his medical issues were over, he resumed
`
`a physically active life. He enjoyed sailing (including sailing from California
`
`to Hawaii and back in a 30-foot boat), parachuting, and bungee jumping. He
`
`remained active during retirement: he and his wife enjoyed many activities
`
`together, such as long walks, scuba diving, travelling, and working in their
`
`vegetable and flower gardens. Alva did a lot of maintenance on houses in
`
`addition to yard work, and he liked to jog.
`
`
`
`In the months before he was diagnosed with stage IV non-Hodgkin’s
`
`lymphoma, Alva experienced great pain to the point where he could barely
`
`move.
`
`
`
`He was treated with six rounds of chemotherapy, which worsened
`
`neurological symptoms that he had exhibited for many years.
`
`
`
`Alva’s cancer went into remission by 2013 and had not recurred at the
`
`time of trial. It is unlikely that the large-cell lymphoma will come back, but
`
`Alva must be monitored for possible complications from the chemotherapy
`
`and for other types of lymphomas, because a personal history of lymphomas
`
`is an increased risk for other lymphomas. Alva has not been able to resume
`
`all his former activities: he no longer works on houses or does long-distance
`
`
`
`9
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`
`
`sailing. Both his son and his wife testified that since his chemotherapy, he
`
`has not been the same as before.
`
`
`
`
`
`2. Alberta’s Diagnosis and Treatment
`
`Alberta retired from teaching and school administration in 2004, and
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`then went back to work as a substitute administrator. Her son described her
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`as “a very social, happy person,” who would go to the gym, walk, snorkel and
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`ski. She and Alva took a trip around the world, and each year Alberta would
`
`travel to Hawaii to visit her son and his family. In spring 2015, shortly
`
`before a planned trip to Hawaii, she began to experience dizziness and
`
`vertigo. The feeling worsened during her trip, and upon returning home she
`
`underwent a series of tests, including a biopsy that required drilling into her
`
`skull. After about a month of testing, she was diagnosed with non-Hodgkin’s
`
`lymphoma in her brain and was told that she would die within 18 months,
`
`regardless of treatment.
`
`
`
`After her 2015 diagnosis, Alberta underwent a painful chemotherapy
`
`regime that required multi-day hospital stays and resulted in illness and
`
`more hospitalization. She went into remission by September 2015 but
`
`suffered a recurrence in her brain in July 2016. She was treated with further
`
`chemotherapy. By October 2017 Alberta showed no evidence of disease. She
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`was placed on an experimental maintenance drug treatment in 2017 and
`
`remained on that treatment at the time of trial; doctors expect she will
`
`continue the drug treatment for the rest of her life.
`
`
`
`Alberta began to suffer depression, which required treatment with
`
`medication. As a result of her cancer, she is generally dizzy, she has double
`
`vision, hearing loss and some memory loss, and she falls frequently. Her
`
`activities are limited because she tires easily. She has not resumed her
`
`annual visits to her son in Hawaii. She testified that she would still be
`
`
`
`10
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`
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`working if not for the cancer and has not been able to travel as a result of her
`
`health as well as her inability to earn money by working. She is embarrassed
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`that when she walks she “just wobble[s] all the time.”
`
`C. Proceedings in the Trial Court
`
`
`
`In 2017, the Pilliods sued Monsanto for compensatory and punitive
`
`damages, alleging that they each developed non-Hodgkin’s lymphoma as a
`
`result of using the same Roundup products. They asserted causes of action
`
`for design defect under the consumer expectations test and failure to warn.
`
`The Pilliods’ claims were based on Monsanto’s labeling, marketing, and
`
`promotion of Roundup. Monsanto denies that Roundup can cause non-
`
`Hodgkin’s lymphoma, and likewise denies that there is any basis to warn
`
`consumers that Roundup can cause non-Hodgkin’s lymphoma. Eventually
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`the case was assigned to the Honorable Winifred Y. Smith, a most
`
`experienced trial judge.
`
`
`
`Monsanto moved to sever the Pilliods’ claims for trial, arguing that one
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`trial involving two plaintiffs with distinct injuries, causation analyses, and
`
`damages could confuse the jury and would prejudice Monsanto and outweigh
`
`any benefit from trying their claims together. Judge Smith denied the
`
`motion.
`
`
`
`Trial ran from late March through early May 2019. The evidence
`
`concerned two primary issues: first, whether Monsanto knew or should have
`
`known that Roundup causes cancer at the time Monsanto manufactured and
`
`distributed the Roundup products that the Pilliods used, and second, whether
`
`Roundup was a substantial factor in causing the Pilliods to develop cancer.
`
`
`
`
`
`1.
`
`The Pilliods’ Witnesses
`
`The Pilliods presented the jury with testimony from a number of
`
`highly-credentialed experts, from physicians who had treated the Pilliods,
`
`
`
`11
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`
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`from Monsanto employees and corporate representatives, and from Alberta,
`
`Alva, and their son.
`
`
`
`The Pilliods’ experts included Dr. Charles Benbrook, an economist with
`
`experience in pesticide use and regulation, who had published peer-reviewed
`
`scientific papers on pesticides, including papers on glyphosate-based
`
`herbicides, and who had researched the regulatory history of glyphosate in
`
`the United States.
`
`
`
`The Pilliods called several experts to testify on issues of causation. Dr.
`
`Christopher Portier, who helped draft the 2005 EPA guidelines for evaluating
`
`the carcinogenicity of chemicals, and who participated as an invited specialist
`
`in the IARC evaluation of glyphosate, testified that Roundup causes tumors
`
`in mammals, malignant lymphoma in mice, genetic damage in human
`
`lymphocytes, oxidative stress in human cells, and probably causes non-
`
`Hodgkin’s lymphoma in humans at real-world exposure. As to non-Hodgkin’s
`
`lymphoma, Dr. Portier testified, “I’m almost 100 percent there, but not 100
`
`percent there. It’s probably yes.” Dr. Portier testified he was in the 90 to 95
`
`percent range, explaining, “The animal evidence is very strong. I’m still less
`
`comfortable with the epidemiology evidence. I would like another one or two
`
`good solid studies in there to get me to that point of absolutely, undeniably,
`
`yes, this causes non-Hodgkin’s lymphoma.”
`
`
`
`Dr. Charles William Jameson, a chemist who for 30 years dedicated his
`
`career to identifying environmental carcinogens and who participated in 12
`
`IARC working groups, including the panel that evaluated glyphosate,
`
`testified that “[t]o a reasonable degree of scientific certainty, glyphosate and
`
`glyphosate-formulated products are probable human carcinogens, and that
`
`data is very strong that glyphosate causes non-Hodgkin’s lymphoma in
`
`exposed workers.”
`
`
`
`12
`
`
`
`
`
`Dr. Beate Ritz, a physician with a Ph.D. in medical sociology and a
`
`Ph.D. in epidemiology who advises the State of California on the health
`
`effects of pesticides, testified at some length about epidemiology studies. In
`
`particular, Dr. Ritz testified about the Agricultural Health Study, a large-
`
`scale epidemiology study of the cancer risk from pesticides, the interpretation
`
`of which was the subject of testimony and argument at trial. (Dr. Ritz had
`
`served on the advisory board for this study.) Dr. Ritz testified that based on
`
`her consideration of animal studies, cell studies, and epidemiology studies
`
`she concluded that Roundup causes non-Hodgkin’s lymphoma in real world
`
`exposure, and that the risk of non-Hodgkin’s lymphoma increases with
`
`increasing exposure to Roundup.
`
`
`
`Dr. Aaron Blair, an epidemiologist who chaired the IARC working
`
`group that evaluated glyphosate, testified about how the working group
`
`operated and about the IARC’s report. He discussed a number of studies on
`
`which the working group relied that showed increased risk of non-Hodgkin’s
`
`lymphoma for people who had been exposed to glyphosate. Dr. Blair
`
`confirmed that, even though he had authored a publication stating that the
`
`results of the Agricultural Health Study did not show an association between
`
`glyphosate and non-Hodgkin’s lymphoma, in the IARC working group he
`
`voted that based on the totality of the evidence, there was an association
`
`between glyphosate and non-Hodgkin’s lymphoma. He testified that the
`
`opinions he had at the IARC meeting had not changed.
`
`
`
`Dr. William Sawyer, a forensic toxicologist who had studied glyphosate
`
`since the 1990’s, testified that based on his review of epidemiology data,
`
`animal data, and mechanism data, Roundup can cause non-Hodgkin’s
`
`lymphoma. He testified that POEA, the toxic surfactant in Roundup
`
`products used by the Pilliods, enhances the genotoxicity of glyphosate, with
`
`
`
`13
`
`
`
`the result that Roundup is about 50 times more genotoxic than glyphosate
`
`alone. He explained that the sprayers used for Roundup create an aerosol
`
`that can drift onto the skin. He also testified that POEA and glyphosate are
`
`skin irritants, and that POEA enhances the absorption of glyphosate through
`
`the skin. He testified that the Pilliods’ exposure to Roundup far exceeded the
`
`level of exposure sufficient to increase their risk of contracting non-Hodgkin’s
`
`lymphoma; and that their exposure was exacerbated by the fact that they did
`
`not wear gloves or other protective gear. If they had worn them when
`
`spraying, their exposure and their risk of getting non-Hodgkin’s lymphoma
`
`would have been reduced. It was undisputed at trial that the Roundup label
`
`for lawn and garden products does not advise users to wear gloves when
`
`using the product.
`
`
`
`Dr. Dennis Weisenburger, a physician board-certified in anatomic and
`
`clinical pathology with special training in the diagnosis of diseases of the
`
`blood and bone marrow (including non-Hodgkin’s lymphoma), testified about
`
`case-specific causation issues as to the Pilliods themselves. He has studied
`
`the relationship between pesticides and non-Hodgkin’s lymphoma since the
`
`1980’s and opined that as a general matter Roundup causes non-Hodgkin’s
`
`lymphoma in humans in real-world exposure. He also opined that, to a
`
`reasonable scientific certainty, repeated Roundup exposure was a substantial
`
`factor in causing non-Hodgkin’s lymphoma in both Alberta and Alva. He
`
`based his opinions on his research in the field, including scientific papers he
`
`read and reviewed as well as papers he authored, and on his review of the
`
`Pilliods’ medical records, their deposition testimony, telephone conversations
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`with the Pilliods, and the deposition testimony of the treating physicians. Dr.
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`Weisenburger testified that up to 70 percent of cases of non-Hodgkin’s
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`lymphoma are idiopathic, meaning that there is no known cause of the
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`disease, but that did not apply to the Pilliods. For the Pilliods, Roundup was
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`“an obvious cause,” and more likely than not the cause of their disease.
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`Dr. Weisenburger explained that he conducted “differential
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`diagnos[e]s” to conclude that environmental exposure to Roundup was a
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`substantial contributing factor in the Pilliods’ illnesses.8 Dr. Weisenburger
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`considered the known accepted causes of non-Hodgkin’s lymphoma, as well as
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`the risk factors for non-Hodgkin’s lymphoma that pertained to each of the
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`Pilliods, including whether the risk factors were substantial in each case. He
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`testified that risk factors for non-Hodgkin’s lymphoma include increased age,
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`male sex, and Caucasian race, but those risk factors do not cause cancer.
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`Other risk factors include pesticide use, a family history of blood cancer,
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`obesity, certain viral infections, certain bacterial infections,
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`immunodeficiency, certain autoimmune diseases, chronic inflammation, and
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`the use of solvents.
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`Dr. Weisenburger testified that only three of the causative risk factors
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`pertained to Alberta: obesity, the use of Roundup (the only pesticide the
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`Pilliods used in any significant amount during the relevant 30 years), and an
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`8 “ ‘Differential diagnosis, or differential etiology, is a standard
`scientific technique of identifying the cause of a medical problem by
`eliminating the likely causes until the most probable one is isolated . . .
`[Citation.] . . . [¶] The first step in the diagnostic process is to compile a
`comprehensive list of hypotheses that might explain the set of salient clinical
`findings under consideration. [Citation.] The issue at this point in the
`process is which of the competing causes are generally capable of causing the
`patient’s symptoms or mortality. . . . [¶] After the expert rules in all of the
`potential hypotheses that might explain a patient’s symptoms, he or she must
`then engage in a process of elimination, eliminating hypotheses on the basis
`of a continuing examination of the evidence so as to reach a conclusion as to
`the most likely cause of the findings in that particular case.’ ” (Johnson &
`Johnson Talcum Powder Cases (2019) 37 Cal.App.5th 292, 308, fn. 6
`(Echeverria).)
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`autoimmune disease, Hashimoto’s thyroiditis. He ruled out Hashimoto’s
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`thyroiditis, because it is associated with lymphomas in the thyroid gland, not
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`the brain, leaving obesity and the use of Roundup. He explained that obesity
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`was a minor risk factor and that it may have contributed to her non-
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`Hodgkin’s lymphoma, but was not a substantial contributing factor.
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`Roundup, on the other hand, was a far greater risk factor than obesity and,
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`because it causes lymphoma and because people exposed to it have a higher
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`increased risk for non-Hodgkin’s lymphoma, was the substantial contributing
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`cause of Alberta’s disease.
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`Dr. Weisenburger testified that with respect to Alva, the relevant risk
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`factors were being overweight (although Alva was not technically “obese”)
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`and exposure to Roundup. His weight put him at a slightly, but not
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`substantially, increased risk for non-Hodgkin’s lymphoma, but Roundup was
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`a substantial contributing factor.
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`Dr. Chadi Nabhan, a physician specializing in lymphoma who is board
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`certified in hematology, oncology, and internal medicine, also testified about
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`case-specific causation issues. He testified that even before he was contacted
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`by the Pilliods’ lawyers, he was well aware that pesticides cause non-
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`Hodgkin’s lymphoma, although he had no knowledge or opinion about
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`Roundup in particular. He also testified that, based on his subsequent
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`research, which included literature and confidential Monsanto documents he
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`received from the Pilliods’ lawyers, as well as literature he researched on his
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`own, Roundup causes non-Hodgkin’s lymphoma. Based on his review of the
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`Pilliods’ medical records, telephone discussions with the Pilliods, and the
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`deposition testimony of the Pilliods and their treating physicians, he testified
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`that Roundup was a cause of Alberta’s and Alva’s non-Hodgkin’s lymphoma.
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`Like Dr. Weisenburger, Dr. Nabhan explained how differential diagnoses led
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`him to conclude that Roundup was a substantial factor in causing each of the
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`Pilliods’ non-Hodgkin’s lymphoma.
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`2. Monsanto’s Witnesses
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`Monsanto, too, offered testimony from highly-credentialed expert
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`witnesses, including Dr. Lorelei Mucci, a leader for the program in cancer
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`epidemiology at the Dana-Farber/Harvard Cancer Center. She opined that
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`based on her “review of all the epidemiology studies, there’s no evidence of a
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`causal association between Roundup and non-Hodgkin’s lymphoma.”
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`Monsanto also presented testimony from two physicians, both experts
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`in lymphoma, who testified on the causes of the disease generally and with
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`respect to the individual plaintiffs. Dr. Celeste Bello testified as to Alberta,
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`and Dr. Alexandra Levine testified as to Alva.
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`Dr. Bello opined that the cause of Alberta’s non-Hodgkin’s lymphoma
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`was unknown, that Roundup did not contribute to her disease, and that the
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`data from epidemiology studies did not support a link between Roundup and
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`non-Hodgkin’s lymphoma. Dr. Bello further opined that Alberta’s medical
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`history showed several risk factors for the development of non-Hodgkin’s
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`lymphoma, including her age, obesity, Hashimoto’s thyroiditis, a personal
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`history of cancer (two incidents of bladder cancer), and a family history of
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`cancer.9
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`9 Dr. Weisenburger and Dr. Nabhan, plaintiffs’ experts on specific
`causation, had testified that age is not a causative risk factor, and that
`Hashimoto’s thyroiditis, the history of bladder cancer, and the family history
`of cancer, which did not include blood-borne cancers, were not risk factors for
`Alberta. They also testified that obesity was not a substantial contributing
`factor to Alberta’s illness. Monsanto argues on appeal that plaintiffs’ experts
`failed to explain why they ruled out cigarette smoking as a cause of Alberta’s
`non-Hodgkin’s lymphoma. But Monsanto ignores testimony from Dr.
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`Dr. Levine characterized Alva’s non-Hodgkin’s lymphoma as having no
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`known cause. She f