# People v. Conagra Grocery Prods. Co.

> California Court of Appeal, 5th District · November 14, 2017 · 227 Cal. Rptr. 3d 499

URL: https://www.frixlaw.com/law-library/cases/6106216

## Case

- **Full name:** The PEOPLE, Cross-defendant and v. CONAGRA GROCERY PRODUCTS COMPANY, and Appellants The Sherwin-Williams Company, Cross-complainant and
- **Court:** California Court of Appeal, 5th District
- **Decided:** November 14, 2017
- **Citations:** 227 Cal. Rptr. 3d 499; 17 Cal. App. 5th 51
- **Precedential status:** Published
- **Opinion:** Opinion of the court by Mihara
- **Judges:** Mihara
- **Cited by:** 62 later opinions in the Frix Law Library

## Citator (automated)

- No negative treatment found by the automated citator. That is not the same as a confirmation that the case is good law; read the citing cases.
- Full citator and citing cases: https://www.frixlaw.com/law-library/cases/6106216

## How later opinions describe it (automated extraction)

- explaining that, “[s]ince laches is an equitable defense, it could not be asserted 23 against the government, even if it were not barred by Civil Code section 3490, because 24 such an application would defeat a public policy aimed at protecting the public” from 25 public nuisa…
- recognizing 12 courts’ “broad discretion to fashion an appropriate abatement injunction”

## Opinion text

Mihara, J.
*514 *65 After a lengthy court trial, the People of the State of California (plaintiff) prevailed in this representative public nuisance action against defendants ConAgra Grocery Products Company (ConAgra), NL Industries, Inc. (NL), and the Sherwin-Williams Company (SWC). 1 The trial court ordered ConAgra, NL, and SWC to pay $1.15 billion into a fund to be used to abate the public nuisance created by interior residential lead paint in the 10 California jurisdictions represented by plaintiff. ConAgra, NL, and SWC (collectively defendants) challenge the court's judgment on many grounds. They contend, among other things, that the court's judgment is not supported by substantial evidence of knowledge, promotion, causation, or *66 abatability. Defendants also challenge the judgment on separation of powers and due process grounds, claim that they were erroneously denied a jury trial, and assert that the trial court made other prejudicial procedural and evidentiary errors. 2 We conclude that the trial court's judgment must be reversed because substantial evidence does not support causation as to residences built after 1950. We also direct the trial court to hold further proceedings on remand regarding the appointment of a suitable receiver. We reject the remainder of defendants' contentions.
I. Plaintiff's Evidence at Trial
"[L]ead is a toxin and causes irreversible brain damage." Childhood lead poisoning *515 is "the number one environmental health problem for children" in California. "Childhood lead poisoning at the level at which it is occurring is definitely an epidemic in California." "The most common source of lead exposure to children in California is lead-based paint and how it contributes to soil and dust contamination in and around housing." 3 Experts have reached a consensus "that lead-based paint is a predominant source of childhood lead exposure [in] pre-1978 housing." 4 Children in pre-1946 housing are subject to "three times the percentage of elevations in blood lead level" as those in post-1978 housing. Lead in homes accounts for at least 70 percent of all childhood lead poisonings. Lead paint is a major contributor to blood lead levels because the lead content of paint is high, while most other lead sources have only trace amounts. And the most common type of lead paint contains white lead carbonate, which is highly absorbable. Between 1929 and 1974, more than 75 percent of the white lead carbonate produced in this country was used in lead paint. Through the 1940s, lead paint contained as much as 50 percent lead.
"Children are exceptionally vulnerable" to lead because "they explore their environment with typical hand-to-mouth contact behavior." Lead paint chips "taste sweet," which may explain why children ingest them. Young children are at especially high risk from residential lead paint because they spend the vast majority of their time in their homes. Infants and young children also *67 absorb much more lead than older children and adults. Because children are smaller, lead intake has a proportionally larger impact on their bodies, and children absorb lead more easily. Children are also more vulnerable to the toxic effects of lead because their biological systems are still developing.
The "brain effects [of lead exposure] in children are irreversible," so the "only option is to prevent the exposure in the first place." There is "no safe exposure level" for lead "[b]ecause no measurable level of lead in blood is known to be without deleterious effects, and because once engendered the effects appear to be irreversible." Blood lead levels less than 5 micrograms per deciliter (mcg/dL) 5 can cause children to suffer impaired intellect and behavioral problems. 6 "[E]ven among children with the lowest levels of lead exposure," studies suggest that "there is ongoing harm down to the lowest measurable levels." "[B]lood lead levels below 5 micrograms per deciliter are associated with decreased academic achievement, diminished IQ scores, or intellectual abilities, cognitive abilities, attention-related behavior problems and antisocial behaviors ...." Lead exposure as a child continues to impact the body when the child becomes an adult. It "has reproductive effects, *516 it has impacts on things like birth weight, and even fertility, delays fertility," and it can be associated with cardiovascular disease.
Even intact lead paint poses a potential risk of future lead poisoning to children because lead paint surfaces will inevitably deteriorate. "[A]ll paint eventually deteriorates. On certain surfaces it deteriorates more rapidly than others[;] mainly those surfaces are high-use surfaces, such as windows and doors." Paint deteriorates when it is exposed to ultraviolet light, water, fungus (such as mildew), friction, or abrasion. More than one-third of pre-1978 homes nationwide with intact lead paint have lead dust. 7 In contrast, only 6 percent of homes without lead paint have lead dust. Lead in soil adjacent to homes generally comes from lead paint, not leaded gas emissions, because post-1978 housing has no soil lead. 8
Most of the housing in the 10 jurisdictions was built before 1980, with the percentages ranging from 51 to 83 percent and is therefore presumed to *68 contain lead paint. 9 Pre-1940 homes are three times as likely to have lead-based paint hazards, 10 with 86 percent having lead-based paint hazards and 67 percent having "significant" lead-based paint hazards such as "deteriorated lead-based paint." 11 "[H]omes with lead-based paint are 10 times more likely than homes without lead-based paint to have dust lead levels on floors and on window sills above the federal limits." And "homes with lead-based paint are more likely to have soil lead levels on the exterior of the home above the EPA [ (federal Environmental Protection Agency) ] criteria limits." Even when lead paint is "intact," soil levels can exceed EPA limits. Lead paint creates soil lead "by the friction and impact surfaces, opening and closing windows and doors on a home with lead-based paint," from the deterioration of exterior lead paint, and from "sanding and scraping" when repainting. When there is lead in the soil, it is often tracked into the home, creating household lead dust.
Since the 19th century, the medical profession has recognized that lead paint is toxic and a poison. An 1878 article by an English doctor recognized that the use of lead paint on the interiors of homes could have poisonous effects on the people who lived in the home. An 1895 article by a San Francisco doctor recounted how a child had been poisoned by lead paint that she *517 had scratched off her crib. A 1904 article by a doctor in Queensland, Australia described multiple cases of children being poisoned by lead dust from lead paint on walls and railings of a house. He believed that the lead dust had been ingested by the children after it got on their fingers and thereby into their mouths. His investigation found lead dust on interior walls where the paint was still in "good condition." 12 An authoritative 1907 textbook edited by a noted American doctor, which was widely used in medical education, discussed the 1904 article and observed that children had been poisoned by lead paint on woodwork in their homes that had produced lead dust and gotten onto their hands. 13 These articles "recognized the dust *69 pathway from paint on a wall, to dust on the floor, to the hands of children, into their mouth[s], as a way of ingestion."
Many medical articles by doctors in the early 20th century described lead poisoning of children from lead paint. A 1917 article by an American doctor discussed the 1904 Australian article and also described the cases of multiple children who had gnawed lead paint off furniture and died. A 1926 article discussed the case of a child who had died from lead poisoning after she "gnawed" lead paint off her bed. A 1933 article pointed out that "children get exposed to lead-based paint in the homes by their common tendency to put things in their mouth[s]." It also stated that most cases involved infants and small children and that children were more susceptible to lead poisoning than adults. Another 1933 article noted: "It must be obvious that for every child who becomes paralysed by lead there must be literally hundreds who have been affected by the poison in some more or less minor degree." "[T]he extent of the lead paint menace has been minimized, and in consequence, literally thousands of children have been allowed to run the risks of lead absorption."
Published medical articles in this era recognized that even small amounts of lead could cause children to suffer harm. A 1931 British Medical Journal article discussed the "insidious" effects of "infinitesimal doses of lead" over a long period of time. A 1935 American medical journal article suggested that there were "insidious" "cumulative effects of infinitesimal doses of lead" that could be "obscure." A 1938 British medical article stated that "the harmful effects of continued small doses of lead begin from the moment the lead is absorbed" and can lead to a long series of "subtle" harms. It opined that "there is no threshold below which still smaller doses can be regarded as being without some adverse effect." A 1943 American medical journal article discussed the impact of early childhood subacute lead poisoning on a child's intelligence and subsequent academic achievement; it called for a ban on interior residential use of lead paint.
Knowledge about the toxic properties of lead paint was not limited to the medical profession. In May 1910, the United States *518 House of Representatives' Committee on Interstate and Foreign Commerce held a hearing on a bill aimed at preventing lead poisoning. The bill would have required products containing white lead to "be labeled conspicuously and securely with a skull and crossbones and the words: 'White lead: poison.' " The sponsor of the bill noted that France had already "entirely prohibited the use of white lead because of its injurious character" and that "all countries of Europe" had *70 already enacted legislation like his proposal. He spoke of "the injurious effect of these atoms of white lead that are filling the air now; they come loose from doors, from window sills, from everywhere, we inhale them and consequently disease is caused which physicians do not understand and can not say what it really is, but it is, in many cases, simply a case of lead poisoning." Another proponent of the bill observed that "the most eminent scientists and doctors of Great Britain" had "found that the small particles that result from chalking, especially from internal painting and external painting as well, when taken by inhalation into the lungs, are absorbed and become a poison to the system." This congressional hearing was attended by an attorney for "practically all of the paint manufacturers of this country" who stated their opposition to the proposal. The bill failed.
A few years later, in 1914, Henry Gardner, who was the assistant director of the Institute of Industrial Research and also the director of the Paint Manufacturers Association's Educational Bureau, published a speech that he had given to the International Association of Master House Painters and Decorators of the United States and Canada at that association's annual convention in February 1914. In this speech, Gardner acknowledged that "the presence of [white lead] dust in the atmosphere of a room is very dangerous to the health of the inmates" and that "[l]ead poisoning may occur through inhalation of [lead] dust ...."
Despite this evidence of the toxic properties of white lead, the main use for white lead in the 20th century was as a pigment for paint. 14 NL, SWC, and ConAgra's predecessor, Fuller, were among the handful of companies that manufactured white lead carbonate pigments during the 20th century, and all three of them used white lead carbonate pigment to make paint. NL, SWC, and Fuller were all leaders in the lead paint industry, and they knew at that time that lead dust was poisonous. They were also aware that lead paint "powders and chalks" "soon after it is applied" and routinely produces lead dust after a couple of years.
In 1922, NL, SWC, and Fuller were making white lead carbonate pigment, using it in their paints, and promoting white lead pigment in paint for use on and in residential homes. Sales of white lead peaked in 1922. There was a decrease in the use of lead paint in the 1920s and early 1930s. By 1944, during World War II, the use of lead paint for residential interiors had declined to a low level.
*71 NL manufactured white lead carbonate pigment from 1891 to 1978, and it had manufacturing facilities in San Francisco and Los Angeles that manufactured white lead carbonate pigments in California between 1900 and 1972. It sold those pigments to California paint manufacturers, used them in its own paint products sold in California, and advertised and promoted paint products containing those pigments for residential use within the 10 jurisdictions *519 during that same period. NL "kept up with the medical literature" about lead poisoning. NL's 1912 annual report acknowledged that lead dust was a "danger to the health" of workers exposed to it in the making of white lead. By the mid to late 1920s, NL knew that children who chewed on things painted with lead paint could get lead poisoning and die from it. Nevertheless, NL's lead paints were marketed for residential use and sold in and advertised in the 10 jurisdictions between 1900 and 1972. NL produced a handbook for consumers in 1950 that instructed them to use lead paint on the interiors of their homes.
ConAgra's predecessor, Fuller, manufactured white lead carbonate pigment from 1894 until at least 1958. Fuller manufactured white lead carbonate pigment at its San Francisco factory until 1898, when it moved its factory to South San Francisco. At this factory, Fuller refined white lead carbonate and was a "major producer" of lead paint. Fuller also had a plant in Los Angeles. Fuller's lead paints were sold at its own stores and by independent dealers in all 10 jurisdictions between 1894 and 1961. 15 Fuller knew that lead dust was poisonous. In 1919, an article about Fuller's South San Francisco plant noted that lead dust is poisonous.
SWC began manufacturing paints containing white lead carbonate pigments in 1880. SWC's internal publication, The Chameleon, published an article in 1900 that acknowledged the many dangers of lead paint. It stated: "A familiar characteristic of white lead is its tendency to crumble from the surface, popularly known as chalking"; "It is also familiarly known that white lead is a deadly cumulative poison"; and "This noxious quality becomes serious in a paint that disintegrates and is blown about by the wind." In 1910, SWC bought a lead mine, which it utilized to manufacture white lead carbonate pigment from 1910 to 1947 for use in its own paints. SWC stopped manufacturing white lead carbonate in 1947, but it continued to make lead paint until 1958. 16 SWC had plants in Emeryville and later in Los Angeles that manufactured paint containing white lead carbonate. SWC continued to sell lead paint until 1972. SWC removed all lead from its residential paints by the end of 1972.
*72 Two trade associations, the Lead Industries Association (LIA) and the National Paint, Varnish, and Lacquer Association (NPVLA) promoted the use of lead paint. Fuller, NL, and SWC were members of both the LIA and the NPVLA. The LIA, which was created in 1928, promoted the use of white lead pigments in residential paint by sponsoring two advertising campaigns, the Forest Products Better Paint campaign and the White Lead Promotion campaign, in the first half of the 20th century. The LIA knew that white lead was being attacked from "a health standpoint," and these campaigns were designed to increase the consumption of lead.
The LIA provided its members with information about lead hazards and lead poisoning that was available in medical and scientific literature at the time. NL was present at a 1930 LIA board of directors meeting at which a 1930 article about lead poisoning of babies and children from chewing lead paint off of cribs was discussed. The article, which ran in the U.S. Daily, a publication "Presenting the Official News" of the government, stated that lead poisoning from "chewing paint from toys, cradles, and woodwork" was "a more *520 frequent occurrence" than previously thought and noted that even a small amount of lead could kill a child. The article also noted that "[c]hildren are very susceptible to lead" and that the "most common sources of lead poisoning in children are paint on various objects within reach of a child and lead pipes ...."
In 1934, the LIA launched its Forest Products campaign, which promoted lead paint for interior residential use. At a 1935 LIA annual meeting, it was acknowledged that childhood lead poisoning disproportionately affected poor and minority children and that there were thousands of cases annually. Yet the LIA fought against the imposition of regulations on lead. A 1937 LIA conference on lead poisoning was attended by representatives from NL and SWC, and Fuller received a transcript of the conference. Both industrial lead poisoning and childhood lead poisoning were discussed at the 1937 conference. There was discussion of research that showed it was nearly impossible to get rid of lead once it got into a child's body. Attendees at the conference were asked by the head of the LIA not to discuss what they learned at the conference in order to avoid unfavorable publicity connecting lead paint to lead poisoning. The LIA's Forest Products campaign continued through 1941.
The NPVLA, unlike the LIA, represented paint manufacturers regardless of whether they used lead pigments. 17 The NPVLA ran advertising campaigns promoting paint throughout the first half of the 20th century. One was called Save the Surface in 1920 and 1921. The other was called Clean Up Paint Up and was ongoing in 1949. All three companies were involved in both *73 advertising campaigns. Neither of the NPVLA's campaigns distinguished between lead paint and non-lead paint, but these campaigns included advertisements promoting all three companies' lead paint products.
Lead paint was banned in the United States in 1978. ( County of Santa Clara v. Atlantic Richfield Co. (2006) 137 Cal.App.4th 292 , 302, 40 Cal.Rptr.3d 313 ( Santa Clara I ).) In 1991, the Centers for Disease Control (the CDC) set the "level of concern" for lead at a blood lead level (BLL) of 10 mcg/dL. 18 In 2012, the CDC replaced this standard with a "reference value" of 5 mcg/dL, which represents the top 2.5 percent of BLLs in children under the age of five. "[T]he reference value simply denotes the worst or the highest exposed children in a population." At that point, national data reflected that 5.3 percent of children living in pre-1950 housing had BLLs exceeding that value, while only 0.4 percent of children living in post-1978 housing had BLLs exceeding that value.
In 1995, the California Legislature enacted the Childhood Lead Poisoning Prevention Act of 1991. ( Health & Saf. Code, §§ 105275, 124125 ; Stats. 1995, ch. 415, § 8.) This act created the Childhood Lead Poisoning Prevention Program (CLPPP). ( Health & Saf. Code, § 124125.) The Childhood Lead Poisoning Prevention Branch (CLPPB), a division of California's Department of Public Health, was accorded the role of coordinating the state's approach to childhood lead exposure and childhood lead poisoning. The CLPPB devotes its resources to outreach, education, case management programs to track those who have been lead poisoned or exposed to lead, and programs to address lead hazards.
*521 The CLPPB also contracts with and supervises 43 county CLPPPs.
The CLPPB focuses on children who are one or two years old. Health care providers are required to order that a child be screened for lead poisoning at age one and at age two if "the child receives services from a publicly funded program for low-income children." ( Cal. Code Regs., tit. 17, § 37100.) Medical laboratories are required to report all BLLs to the CLPPB. ( Health & Saf. Code, § 124130 ; Stats. 2002, ch. 931, § 11.) The CLPPB considers it a "case" of lead poisoning if a child's BLL exceeds 19.5 mcg/dL or persistently exceeds 14.5 mcg/dL. In such cases, a public health nurse and an environmental health specialist visit the child's home to try to determine potential sources of the lead poisoning.
National average BLLs have declined precipitously since the 1970s, falling by about 90 percent. In 1980, it was estimated that 88.3 percent of children had BLLs in excess of 10 mcg/dL. By 2008, it was estimated that less than one *74 percent of children had BLLs over 10 mcg/dL. 19 Nevertheless, in 2010, around 22,000 children under the age of six in California had BLLs over 4.5 mcg/dL. And at the time of trial in 2013, California had more than 2,000 children with BLLs over 10 mcg/dL and more than 15,000 additional children with BLLs over 5 mcg/dL. Children in California with BLLs over 9.5 mcg/dL represented 0.35 percent of California's children. 20
Children in the 10 jurisdictions are continuing to be exposed to lead from the lead paint in their homes and to suffer deleterious effects from that lead. Although only a small percentage of the children in these jurisdictions are screened for lead, thousands of children are found to have BLLs of concern each year.
Lead poisoning from lead paint is "the number one environmental children's health issue in Alameda County." The primary cause of lead poisoning in Alameda County is lead paint. About 75 percent of Alameda County's homes are pre-1980, which amounts to 430,000 units. Nearly 174,000 of those units are pre-1950. Alameda County is able to screen only 46 percent of the children under the age of six who are poor and live in pre-1978 homes. Alameda County's CLPPP opens a case only when there is a lead-poisoned child with a BLL of 20 mcg/dL or two BLLs of 15 mcg/dL. In 2012, 14 children met that standard in Alameda County. That triggers an investigation of the home and education of the parents about sources of exposure. There is no funding for remediation. Alameda County's CLPPP also tries to do outreach and education to families with children who have BLLs of 5 mcg/dL or higher, 21 but there is no funding for dealing with these children. In 2010, there were 14 children in that category.
Lead poisoning is the top pediatric environmental health problem in Los Angeles County. The most common source of lead poisoning in Los Angeles County is lead paint chips and lead paint dust. Lead paint is a "severe environmental health concern" in Los Angeles County. In Los Angeles County, 77 percent of the housing was *522 built before 1978, which is more than 2.6 million housing units. More than 900,000 of those housing units are pre-1950. Los Angeles County's investigators have often found lead paint dust in homes with intact lead paint. In 2010, Los Angeles County had about 6,500 children under the age of six with BLLs of greater than 4.5 mcg/dl. Los Angeles County's CLPPP generally does not do "primary prevention" but *75 only screening and "secondary prevention." Los Angeles County's CLPPP handles about 75 to 100 cases of lead poisoning each year. In at least 75 percent of those cases, lead paint is a potential source of the lead poisoning. At least 70 percent of those cases involve pre-1978 housing.
Lead paint is a serious environmental health concern in Monterey County. In Monterey County, 66 percent of the housing was built before 1980, which accounts for between 89,000 and 90,000 units. Between 18,000 and 19,000 of those units were built before 1950. Each year, Monterey County's CLPPP receives between 13 and 15 new cases where there has been a report of a BLL of 20 mcg/dL or two BLLs of 14.5 mcg/dL or greater. The children are generally between the ages of one and three. For those cases, it conducts a full assessment of the home. Each month Monterey County receives 10 to 20 reports of a child with a BLL of 4.5 mcg/dL or higher. A substantial number of cases of lead poisoning in Monterey County have been attributed to imported foods.
Lead-based paint hazards in Oakland homes are "coming close to crisis mode." In Oakland, 80 to 90 percent of the housing is pre-1978, which accounts for about 174,000 units. Each year, Oakland's Lead Safe Housing Program receives 16 to 20 referrals from Alameda County's CLPPP to assess homes where lead-poisoned children live.
In the City of San Diego, 60.5 percent of the housing was built before 1980. There are about 300,000 pre-1978 housing units of which more than 62,000 are pre-1950. The City of San Diego has a Lead Safety Healthy Homes Program that offers education, outreach, risk assessments, and lead inspections. More than half of the 2,700 lead inspections completed in the City of San Diego between 2005 and 2013 identified lead hazards.
In San Francisco, 94 percent of the homes were built before 1978, which is more than 317,000 housing units, and 68 percent were built before 1950, which is more than 235,000 housing units. About 22,000 housing units in San Francisco that are occupied by low and moderate income families are believed to have lead-based paint hazards. San Francisco's CLPPP contacts parents when a child tests at 2 mcg/dL or higher. Only very infrequently is the source of the child's lead exposure anything other than lead paint. In 2010, when San Francisco tested 10,300 children under the age of six, 959 children tested between 4.5 and 9.5 mcg/dL, and 35 tested higher. Since 2010, San Francisco has been "seeing increasing numbers" of lead exposed children. Each year, San Francisco issues about 200 notices to correct lead paint and soil lead hazards.
The number one source of lead poisoning in San Mateo County is lead paint. Lead paint in pre-1978 housing is a public health problem in San *76 Mateo County. This includes intact lead paint because it will inevitably deteriorate. In San Mateo County, 80 to 90 percent of the housing is pre-1978, which is more than 200,000 housing units. More than 56,000 of those units are pre-1950.
"[L]ead paint is the number one environmental cause of poisoning of children in Santa Clara County" and is a threat to public health there. In Santa Clara County, *523 two-thirds of the housing stock is pre-1978, which is more than 426,000 housing units. More than 61,000 of those are pre-1950. Although in 2010 Santa Clara County could only afford to test less than 20 percent of the more than 150,000 children under the age of six who lived in the county, 339 of them had BLLs between 4.5 mcg/dL and 9.5 mcg/dL, and 71 had BLLs over 9.5 mcg/dL. Most of the children with elevated BLLs lived in pre-1978 housing. "[O]nce those children are determined to be lead poisoned, it is too late."
Lead poisoning of children is a "very significant problem" in Solano County, and it "causes substantial harm even at the lowest levels of exposure" such as 5 mcg/dL. "The harm is very substantial, the harm is permanent. Children's IQs are affected ... they have impairment of memory, difficulty with problem solving, inattentiveness ...." Only about 20 percent of the 32,000 children under age six in Solano County are tested for lead. This is due to lack of access to medical care for poor children. In 2010, at least 100 children in Solano County had BLLs over 4.5 mcg/dL. Between 2001 and 2012, the sole source of lead exposure was lead paint for 55 percent of the children in Solano County with a BLL of 20 mcg/dL or higher or two BLLs of 15 mcg/dL. In many of the other cases, lead paint was a contributing source. Between 75,000 and 80,000 homes in Solano County were built before 1978, which is about 51 percent of all of the homes. More than 18,000 of those units are pre-1950. Solano County has no resources for code enforcement of lead paint hazards in homes or for remediation.
Ventura County has almost 174,000 pre-1978 housing units. Almost 20,000 of those are pre-1950. In 2010, Ventura County had 34 children with BLLs higher than 10 mcg/dL and 271 children with BLLs over 5 mcg/dL. Ventura County's CLPPP does not do any environmental investigation as to children with BLLs between 5 and 15 mcg/dL. For those children, Ventura's CLPPP provides only educational material.
The CLPPPs lack the ability to engage in primary prevention, which seeks to prevent lead exposure in the first place. Instead, the CLPPPs largely target children who have already been exposed to lead. Abatement would be primary prevention. Although it is not feasible to remove all lead from every home in the 10 jurisdictions, primary prevention could be substantially *77 furthered by lead inspections, risk assessments, education, and remediation of identified lead hazards in homes in the 10 jurisdictions.
II. Defense Evidence At Trial
BLLs in children under the age of six nationally have been dropping since the 1970s, going from a geometric mean of 15 mcg/dL in the late 1970s to 1 mcg/dL in 2009/2010. The percentage of children under the age of six with BLLs exceeding 10 mcg/dL has dropped over that period from more than 80 percent to less than one-half of one percent. A similar drop has occurred for children under the age of six with BLLs over 5 mcg/dL. The same is true in the western region, which includes California, where the geometric mean for BLLs is about 25 to 30 percent lower than in other regions. In most of the 10 jurisdictions, BLLs and the percentage of elevated BLLs also dropped from 2007 to 2012.
A defense expert testified that the lower BLLs reflected decreasing exposure of children to lead. It was his opinion that leaded gasoline was largely responsible for both soil lead and dust lead and that there was "very little impact of exposure to lead from paint on community-wide blood lead levels."
*524 Another defense expert testified that the current understanding of childhood lead poisoning was unknown before 1970. In his view, the amount of lead considered toxic and awareness of "the pathway by which lead gets into the child's body" had both "changed radically over the years." He asserted that in the first decade of the 20th century lead poisoning was considered an "industrial disease of adults." No tests were available to measure a BLL. It was not until the 1930s that a BLL test became available. This defense expert testified that, prior to 1920, there were no cases in the United States of a child ingesting lead paint from a household surface. By 1940, interior use of lead paint was dwindling. In 1951, Baltimore banned lead paint for interior use. In 1953, there was a general call for lead paint not to be used for interiors.
This defense expert testified that in 1971, the medical community's understanding was that lead poisoning did not cause significant symptoms until the BLL exceeded 60 mcg/dL. In 1970, the United States Surgeon General determined that a BLL of 40 mcg/dL should be considered "evidence suggestive of undue absorption of lead ...." It was not recognized until 1974 that children could consume lead originating from lead paint from household dust, rather than only from flakes and chips. In 1985, the CDC set an "intervention level" for BLLs at 25 mcg/dL. In 1991, the CDC set the "level of concern" for BLLs at 10 mcg/dL.
A defense epidemiologist testified that it was not clear even in 2003 whether BLLs below 10 mcg/dL produced cognitive deficits. This expert *78 testified that a subsequent study authored by one of plaintiff's experts showing such deficits was flawed. This expert had not studied childhood lead exposure, but he testified that the evidence was inconclusive whether there were cognitive effects of BLLs below 10 mcg/dL.
SWC presented a statistician who testified that SWC had contributed only 6,732 tons of lead to California over the period from 1894 to 2009 out of a total of 217,784 tons of lead consumed in California during that period, which was just ".1 percent" of the total lead. On cross-examination, he conceded that his estimate was limited to lead manufactured by SWC between 1910 and 1947, which was the only period when SWC manufactured lead. SWC continued to make lead paint after 1947. His estimate was also based primarily on national data about lead consumption to which he had applied a ratio based solely on population to determine what he thought was California's consumption.
Another defense expert testified that lead paint does not inevitably deteriorate. He asserted that if lead paint is "maintained properly and re-coated as needed on a regular maintenance cycle," it will not deteriorate. His premise was that repainting would be needed every three to five years. On cross-examination, he admitted that lead paint would deteriorate over time, particularly on friction surfaces like windows. He also admitted that repainting would require surface preparation, which would often mean sanding or scraping, in order to provide a surface to which the new paint would adhere.
The defense's abatement expert testified that the replacement of windows and doors that have been painted with lead paint is "a very intrusive and disruptive process" that involves "guys in moon suits, [and] respirators." That process can disturb other hazardous waste, such as asbestos, and lead to the discovery of mold issues. The remediation of floors and soil would also be invasive, labor intensive, and time consuming. He also suggested that the abatement plan's cost estimates for remediation were *525 unrealistically low. He believed that remediation would often take a week or more and could increase the risk of lead exposure for the residents of the home. He also testified that replacing windows does not lower BLLs and that remediation can result in higher BLLs.
III. Procedural Background
In March 2011, plaintiff filed a fourth amended complaint (FAC) for public nuisance. 22 It named as defendants ConAgra, NL, SWC, Atlantic Richfield *79 Company (ARCO), E.I. Du Pont de Nemours and Company (DuPont), and 50 Doe defendants. 23 The FAC alleged that the presence of lead in homes was a public nuisance and that defendants were "liable in public nuisance" because they had created or assisted in the creation of this public nuisance. 24 Plaintiff sought abatement, injunctive relief, costs, and attorney's fees. The parties stipulated that the FAC concerned only residential buildings and no public buildings.
The court struck defendants' jury demands, and the case was tried to the court in July and August 2013. In March 2014, the court issued an amended statement of decision and an amended judgment. The court's amended statement of decision, which was over 100 pages long, made numerous findings. The court expressly found that, "[s]ince antiquity, it has been well known that lead is highly toxic and causes severe health consequences when ingested" and that "[e]ven relatively low levels of lead exposure have severe health consequences." It found that lead paint is prevalent in the 10 jurisdictions, "inevitably deteriorates," and is the primary source of lead exposure for young children living in pre-1978 housing in the 10 jurisdictions. As a result, children in these jurisdictions are continuing to be exposed to lead from lead paint even though residential lead paint was banned in 1978. The court expressly found that ConAgra, NL, and SWC each had "actual knowledge of the hazards of lead paint," "including childhood lead poisoning," when they promoted lead paint for interior residential use. The court's judgment required defendants to pay $1.15 billion into an abatement fund that would pay for lead inspections, education about lead hazards, and remediation of particular lead hazards inside residences in the 10 jurisdictions. Defendants timely filed notices of appeal. 25
IV. Discussion
A. Substantial Evidence Issues
A public nuisance cause of action is established by proof that a defendant knowingly created or assisted in the creation of a substantial and unreasonable interference with a public right. ( Santa Clara I , supra , 137 Cal.App.4th at pp. 305-306, 40 Cal.Rptr.3d 313 .)
*526 *80 Defendants contend that plaintiff failed to produce substantial evidence in support of its public nuisance cause of action. They assert that substantial evidence does not support the trial court's findings that (1) they had actual knowledge of the public health hazard posed by interior use of lead paint at the time they promoted and distributed it; (2) they promoted lead paint for interior use; (3) their conduct caused the public nuisance to occur; and (4) the nuisance is abatable, lead paint poses an imminent danger, and abatement will lower BLLs.
1. Standard of Review
Defendants contend that their claims that substantial evidence does not support the trial court's judgment raise questions of law that we must review de novo. They cite Smith v. Selma Community Hosp. (2008) 164 Cal.App.4th 1478 , 80 Cal.Rptr.3d 745 ( Smith ) as support for this contention. Smith is inapposite. In Smith , the Court of Appeal was reviewing a governing board's decision reviewing a judicial review committee's decision. The board, which was exercising substantial evidence review, concluded that the committee's decision was not supported by substantial evidence. Since the Court of Appeal was reviewing the board's decision that substantial evidence did not support the committee's decision, the Court of Appeal necessarily exercised independent review. ( Smith , at pp. 1515-1516, 80 Cal.Rptr.3d 745 .) As we are not reviewing another reviewing body's decision as to whether a third body's decision was supported by substantial evidence, we do not exercise independent review. Instead, we exercise ordinary deferential substantial evidence review.
" 'When a finding of fact is attacked on the ground that there is not any substantial evidence to sustain it, the power of an appellate court begins and ends with the determination as to whether there is any substantial evidence contradicted or uncontradicted which will support the finding of fact.' " ( Foreman & Clark Corp. v. Fallon (1971) 3 Cal.3d 875 , 881, 92 Cal.Rptr. 162 , 479 P.2d 362 .) " '[W]e have no power to judge of the effect or value of the evidence, to weigh the evidence, to consider the credibility of the witnesses, or to resolve conflicts in the evidence or in the reasonable inferences that may be drawn therefrom.' " ( Leff v. Gunter (1983) 33 Cal.3d 508 , 518, 189 Cal.Rptr. 377 , 658 P.2d 740 .) Our role is limited to determining whether the evidence before the trier of fact supports its findings. ( Reddy v. Gonzalez (1992) 8 Cal.App.4th 118 , 123, 10 Cal.Rptr.2d 55 .)
Defendants claim that we may not presume implied findings in plaintiff's favor because there were "key ambiguities" in the trial court's statement of decision that they brought to the court's attention but the court did not resolve.
*81 "When a statement of decision does not resolve a controverted issue, or if the statement is ambiguous and the record shows that the omission or ambiguity was brought to the attention of the trial court ... , it shall not be inferred on appeal ... that the trial court decided in favor of the prevailing party as to those facts or on that issue." ( Code Civ. Proc., § 634.) "To bring defects in a statement of decision to the trial court's attention within the meaning of section 634, objections to a statement of decision must be 'specific.' [Citation.] The alleged omission or ambiguity must be identified with sufficient particularity to allow the trial court to correct the defect. [Citation.] 'By filing specific objections to the court's statement of decision a party pinpoints alleged deficiencies in the statement and allows the court to focus on the facts or issues the party contends were *527 not resolved or whose resolution is ambiguous.' " ( Ermoian v. Desert Hospital (2007) 152 Cal.App.4th 475 , 498, 61 Cal.Rptr.3d 754 .) "[A] trial court is not required to respond point by point to issues posed in a request for a statement of decision. ' "The court's statement of decision is sufficient if it fairly discloses the court's determination as to the ultimate facts and material issues in the case." [Citations.]' " ( Id. at p. 500, 61 Cal.Rptr.3d 754 .)
After trial, each defendant submitted a proposed statement of decision, and plaintiff submitted proposed findings of fact and law and a proposed order. In December 2013, the court issued a proposed statement of decision. Plaintiff and defendants filed objections to the proposed statement of decision. The court subsequently filed an amended statement of decision and an amended judgment. 26
Defendants' appellate briefs identify six "key ambiguities" that they assert they brought to the court's attention but the court failed to address in its statement of decision. The alleged "ambiguities" they identify are: (1) "Whether the court found any part of defendants' recitation of the historical knowledge of lead hazards to be incorrect;" (2) "What level of lead exposure the court referred to as being 'lead poisoning ' "; (3) "What facts about lead's hazards the court found that defendants 'actually knew' "; (4) "Which of defendants' promotions for interior paint the court found to be a basis for liability"; (5) "On what basis the court included housing built after 1950"; and (6) "what public rights."
"[I]t is settled that the trial court need not, in a statement to decision, 'address all the legal and factual issues raised by the parties.' [Citation.] It 'is *82 required only to set out ultimate findings rather than evidentiary ones.' [Citation.] ' "[U]ltimate fact[ ]" ' is a slippery term, but in general it refers to a core fact, such as an element of a claim or defense, without which the claim or defense must fail. [Citation.] It is distinguished conceptually from 'evidentiary facts' and 'conclusions of law.' " ( Yield Dynamics, Inc. v. TEA Systems Corp. (2007) 154 Cal.App.4th 547 , 559, 66 Cal.Rptr.3d 1 .)
Only one of defendants' six alleged "ambiguities" arguably pertains to a "core fact" rather than an evidentiary fact. SWC's objections to the court's proposed statement of decision asked the court to "define 'harmful' " with respect to defendants' knowledge of lead's harmful nature. SWC argued that this was important because the state of knowledge at the time defendants promoted lead paint did not include knowledge of the risks of low-level exposure to deteriorating lead paint. ConAgra adopted SWC's objections and also asked the court to "specify what hazard it finds that Fuller knew when it promoted lead paint for residential interior use, and when Fuller knew exposure to lead at even minute levels was harmful." ConAgra requested that the court specify "what 'harm' each defendant 'knew.' " NL objected to the court's proposed knowledge findings and asked that the court "specifically identify the knowledge that NL had at that time." We address the court's treatment of the "harms" and "hazards" issue in the course of our analysis of defendants' challenge to the court's knowledge findings.
*528 In all other respects, we reject defendants' claim that the court failed to resolve an ambiguity as to a "core fact" because we conclude that the alleged ambiguities concerned evidentiary facts.
Before we embark on our substantial evidence review, we note that we cannot rely solely on the expert testimony produced by plaintiff. Plaintiff's expert witnesses testified to conclusions that would appear on their face to establish both the actual knowledge and promotion elements of plaintiff's case. One of plaintiff's experts testified: "These Defendants manufactured white lead carbonate; these Defendants knew of the hazards of lead during the time that they were manufacturing white lead carbonate; these Defendants advertised, promoted, and sold their lead and/or lead [based] products while they had knowledge of the hazards of lead; these Defendants advertised, promoted, and sold their lead and/or lead containing products for use in and around homes within each of the 10 jurisdictions; suitable substitutes were available for white lead; these Defendants, through their trade association, downplayed the hazards of lead; and these Defendants, through their trade associations, fought the imposition of regulations." And plaintiff's experts testified to even more specific conclusions: "Sherwin-Williams had actual knowledge about the hazards of lead as early as 1900."
If we could accept plaintiff's expert witnesses' testimony at face value , this testimony would itself support the trial court's findings. However, *83 we may not do so. " 'The chief value of an expert's testimony in this field, as in all other fields, rests upon the material from which his opinion is fashioned and the reasoning by which he progresses from his material to his conclusion; ... it does not lie in his mere expression of conclusion.' " 27 ( People v. Bassett (1968) 69 Cal.2d 122 , 141, 70 Cal.Rptr. 193 , 443 P.2d 777 .) "Where an expert bases his conclusion upon assumptions which are not supported by the record, upon matters which are not reasonably relied upon [by] other experts, or upon factors which are speculative, remote or conjectural, then his conclusion has no evidentiary value. [Citations.] In those circumstances the expert's opinion cannot rise to the dignity of substantial evidence. [Citation.] When a trial court has accepted an expert's ultimate conclusion without critical consideration of his reasoning and it appears the conclusion was based upon improper or unwarranted matters, then the judgment must be reversed for lack of substantial evidence." ( Pacific Gas & Electric Co. v. Zuckerman (1987) 189 Cal.App.3d 1113 , 1135-1136, 234 Cal.Rptr. 630 .) "If [the expert's] opinion is not based upon facts otherwise proved, or assumes facts contrary to the only proof, it cannot rise to the dignity of substantial evidence." ( Estate of Powers (1947) 81 Cal.App.2d 480 , 485-486, 184 P.2d 319 .)
Consequently, a conclusion expressed by an expert cannot provide by itself substantial evidence to support a finding unless the basis for the expert's conclusion is itself supported by substantial evidence. Our substantial evidence review must include a critical examination of the material upon which the experts based *529 their conclusions in order to determine whether that material provides substantial support for those conclusions.
2. Actual Knowledge
Defendants claim that the trial court did not find actual knowledge, but only constructive knowledge, and that its knowledge findings are not supported by substantial evidence.
Constructive knowledge would not be sufficient to support plaintiff's public nuisance cause of action. The standard set by this court in Santa Clara I is actual knowledge, not constructive knowledge. "[L]iability is premised on defendants' promotion of lead paint for interior use with knowledge of the hazard that such use would create. This conduct is distinct from and far more *84 egregious than simply producing a defective product or failing to warn of a defective product .... [¶] A public nuisance cause of action is not premised on a defect in a product or a failure to warn but on affirmative conduct that assisted in the creation of a hazardous condition. Here, the alleged basis for defendants' liability for the public nuisance created by lead paint is their affirmative promotion of lead paint for interior use, not their mere manufacture and distribution of lead paint or their failure to warn of its hazards." ( Santa Clara I , supra , 137 Cal.App.4th 292 , 309-310, 40 Cal.Rptr.3d 313 , boldface & italics added.) By tethering the public nuisance cause of action to affirmative promotion for a use defendants knew to be hazardous , this court necessarily set forth an actual knowledge standard. If the standard had been only constructive knowledge, the affirmative promotion of a product for a particular use that was hazardous would not have been "far more egregious" than simply failing to warn of a defective product.
We reject defendants' claim that the trial court did not find "actual knowledge." The trial court's statement of decision expressly found that all three defendants had "actual knowledge of the hazards of lead paint-including childhood lead poisoning" when they produced, marketed, sold, and promoted lead paint for residential use. It found: "ConAgra had actual knowledge of the hazards of lead paint-including childhood lead poisoning-for the duration of its production, marketing, and sale of lead pigments and paint for home use"; "NL had actual knowledge of the hazards of lead paint, including childhood lead poisoning"; "SW[C] had actual knowledge of the hazards of lead paint-including childhood lead poisoning-for the duration of its production, marketing, and sale of lead pigments and lead paint for home use."
While the standard we established in Santa Clara I is actual knowledge, our substantial evidence review remains deferential, and we must accept any reasonable inferences that the trial court drew from the evidence before it. The fact that the trial court was required to find actual knowledge does not mean that the court could not rely exclusively on circumstantial evidence to support such a finding. The only limit on the trial court's reliance on inferences from circumstantial evidence to establish actual knowledge is that those inferences may not be speculative or conjectural. " ' "Actual knowledge can be inferred from the circumstances only if, in the light of the evidence, such inference is not based on speculation or conjecture. Only where the circumstances are such that the defendant ' must have known ' and not 'should have known' will an inference of actual knowledge be permitted." [Citation.]' " ( Romero v. Superior Court (2001) 89 Cal.App.4th 1068 , 1082, 107 Cal.Rptr.2d 801 .) This distinction between what a defendant must have known and what a defendant *530 should have known is crucial. Proof of actual *85 knowledge focuses on what information a defendant must have been aware of, while proof of constructive knowledge rests on a defendant's duty to discover information.
We reject defendants' claim that the court left undefined the nature of the "hazard" or "harm" that defendants had knowledge of when they promoted lead paint for interior residential use. The court expressly found that defendants "learned about the harms of lead exposure through association-sponsored conferences." It expressly found that defendants knew in the 1930s that "the dangers of lead paint to children were not limited to their toys, equipment, and furniture." The court expressly found that defendants knew both that "high level exposure to lead-and, in particular, lead paint-was fatal" and that "lower level lead exposure harmed children." The court also found that, by the 1920s, defendants knew that "lead paint used on the interiors of homes would deteriorate, and that lead dust resulting from this deterioration would poison children and cause serious injury."
The trial court's express findings made clear that the "harms" and "hazards" of which defendants had actual knowledge included that (1) "lower level lead exposure harmed children," (2) "lead paint used on the interiors of homes would deteriorate," and (3) "lead dust resulting from this deterioration would poison children and cause serious injury." Because the trial court made the express findings that defendants sought in their objections to the court's proposed statement of decision, we are not precluded from drawing inferences in support of the trial court's decision. In any case, the court's express findings fully suffice to support its decision.
Here, the trial court properly focused on evidence of information that defendants must have been aware of under the circumstances. This evidence was sufficient to support a reasonable inference that each defendant must have known by the early 20th century that interior residential lead paint posed a serious risk of harm to children.
First, evidence before the trial court established that, by 1914, it was well known in the paint manufacturing industry that deteriorated lead paint on residential interiors, particularly doors and windowsills, released "small particles" of lead into the air, which were "very dangerous" to and could be ingested by humans and "poison" them.
In May 1910, the United States House of Representatives' Committee on Interstate and Foreign Commerce held a hearing on a bill aimed at preventing lead poisoning. The bill would have required products containing white lead to "be labeled conspicuously and securely with a skull and crossbones and the words: 'White lead: poison.' " Congressman Richard Bartholdt, who was *86 the sponsor of the proposal, explained to the committee that "the painters of the United States," who had originally opposed the proposal, had "practically all come around now" to supporting regulation of white lead. Bartholdt pointed out that France had already "entirely prohibited the use of white lead because of its injurious character" and that "all countries of Europe" had already enacted legislation like his proposal.
Bartholdt explained: "We know very little of the injurious effect of these atoms of white lead that are filling the air now; they come loose from doors, from window sills, from everywhere, we inhale them and consequently disease is caused which physicians do not understand and can not say what it really is, but it is, in many cases, simply a case of lead poisoning." One of *531 the proponents of the bill told the committee that "the most eminent scientists and doctors of Great Britain" had "found that the small particles that result from chalking, especially from internal painting and external painting as well, when taken by inhalation into the lungs, are absorbed and become a poison to the system." He also stated that an "eminent scientist" in London had said that occupying a room that had been painted with white lead was "dangerous."
Eugene Philbin attended the hearing as "counsel for, I think, practically all of the paint manufacturers of this country-the leading ones," to state their opposition to the proposal. Philbin said that he represented not only the "Paint Manufacturers' Association" but also the "National Paint, Oil, and Varnish Association." Philbin objected to the "poison provision" on the ground that it was "entirely unnecessary" and would "create a fear on the part of the consumer." The bill failed.
A few years later, in 1914, Gardner, the director of the Paint Manufacturers Association's Educational Bureau, published a speech that he had given to the International Association of Master House Painters and Decorators of the United States and Canada at that association's annual convention in February 1914. In this speech, Gardner acknowledged that "the presence of [white lead] dust in the atmosphere of a room is very dangerous to the health of the inmates." He observed that "[l]ead poisoning may occur through inhalation of [lead] dust ...." Gardner suggested that "white lead flatted with turpentine" was to blame for the disintegration of white lead paint into white lead dust. 28 However, Gardner expressed the belief that "the use of flatted white lead has been largely abandoned for wall and ceiling decoration, and its place has been taken by the more sanitary leadless Flat Wall Paints."
*87 Notwithstanding Gardner's belief, interior residential use of lead paint continued throughout the first half of the 20th century despite widespread knowledge in the paint industry of the toxic properties of white lead. NL, SWC, and Fuller were all leaders in the lead paint industry. SWC proclaimed itself in 1901 to be "the largest manufacturer of Prepared Paint in the world." In 1934, SWC called itself the "World's Largest Paint Producer" and identified itself as "one of the country's largest producers of White Lead." NL took pride in its position as a leader in the white lead industry since 1891. In 1912, NL made more than 20 different brands of Dutch Boy White Lead for painting, the brand that it had adopted in 1907. By the late 19th century, Fuller was the leading seller of white lead on the West Coast and was "one of the strongest concerns dealing in paints, oils and glass in the United States."
NL, SWC, and Fuller, as leaders in the lead paint industry were well aware in the early part of the 20th century that lead dust was poisonous. They were also aware that lead paint "powders and chalks" "soon after it is applied" and routinely produces lead dust after a couple of years. Both the May 1910 congressional hearing and the published 1914 Paint Manufacturing Association speech plainly discussed the dangers posed by interior residential use of lead paint. Because defendants were leaders in the paint industry at that time, they must have been aware of hazards related *532 to their products that were well known in the paint industry. It is neither speculative nor conjectural to draw a reasonable inference that leaders in the paint industry were aware of a serious hazard caused by their product when this hazard was generally known in their industry. Indeed, it would be unreasonable to infer that, notwithstanding general knowledge of the hazard of their products within the industry, defendants somehow managed to avoid learning of this hazard.
Second, the reasonable inference arising from the 1910 and 1914 evidence of what was generally known in the paint industry was further supported by evidence that Fuller, NL, and SWC were each the recipient of confirmatory information about this hazard from the LIA in the 1930s. Each of the defendants was a member of the LIA in the 1930s when the LIA promulgated information to its members about the "frequent occurrence" of children being poisoned by lead paint from "toys, cradles, and woodwork," which included the fact that even a small amount of lead could kill a child. The LIA information given to its members (including all three defendants) referenced a national newspaper article that had stated that "[c]hildren are very susceptible to lead" and that the "most common sources of lead poisoning in children are paint on various objects within reach of a child and lead pipes ...." Defendants, as the recipients of this information from the LIA, must have been aware at that time, in the early 1930s, of the hazard to children created by the interior residential use of lead paint. The fact that this information *88 confirmed the prior information of which they also must have been aware served to solidify the foundation for the trial court's actual knowledge findings.
All of this evidence provided substantial support for the trial court's actual knowledge findings as to the three defendants under our deferential standard of review. "The fact that it is possible to draw some inference other than that drawn by the trier of fact is of no consequence. ... We must therefore view the evidence in the light most favorable to the prevailing party, giving it the benefit of every reasonable inference ...." ( Jessup Farms v. Baldwin (1983) 33 Cal.3d 639 , 660, 190 Cal.Rptr. 355 , 660 P.2d 813 .)
Here, the evidence, while circumstantial, was sufficient to support reasonable inferences that defendants must have known in the early 20th century that interior residential lead paint posed a serious risk of harm to children. Since these reasonable inferences support the trier of fact's express findings that NL, SWC, and Fuller harbored the requisite actual knowledge, our deferential standard of review precludes us from drawing contrary inferences, and we must uphold the trial court's actual knowledge findings.
ConAgra claims that there was no evidence that its predecessor, Fuller, knew in the early 20th century that the use of lead paint in residential interiors would pose a public health hazard. It maintains that Fuller either did not know that children were consuming lead paint or knew of only "isolated cases" of such behavior that did not amount to a public health hazard. ConAgra also contends that Fuller could not have been aware of the risk of lower BLLs, since no test for BLLs existed at the time, and could not have known of the specific pathways by which children consume lead dust, which were not proved until much later.
By 1914, as a major producer of lead paint since the previous century, Fuller was well aware of the public health hazard posed to children by interior residential lead paint. The 1910 congressional hearing and the 1914 published speech provide very strong circumstantial evidence of *533 Fuller's actual knowledge. Fuller could not have failed to learn from the hearing and the article that deteriorated interior residential lead paint posed a "very dangerous" risk to the "health" of the inhabitants of those residences. Of course, this knowledge was reinforced by information that the LIA distributed to its members, including Fuller, in the 1930s discussing how it was a *89 "frequent occurrence" that children were poisoned by lead paint from "toys, cradles, and woodwork" and noting that even a small amount of lead could kill a child. 29
In light of these facts, there is no merit to ConAgra's claims that Fuller did not know children were consuming lead paint, that Fuller believed that such events were infrequent, and that Fuller could not have known that a small amount of lead could harm a child. Since Fuller was aware that deteriorating interior residential lead paint exposed the occupants of the residence to "very dangerous" lead dust, knowledge of the specific pathway by which children consume lead dust was not essential for Fuller to be aware that lead paint on residential interiors posed a risk of serious harm to children.
ConAgra also claims that the evidence was insufficient to show Fuller's knowledge because the trial court erroneously permitted plaintiff's experts to opine about Fuller's knowledge. Since the material upon which the experts' opinions were based provides substantial support for those opinions, the court did not err in admitting and relying on those opinions. We assess ConAgra's claim that some of the documents relied on by the experts were inadmissible hearsay in section IV(J)(1) of this opinion.
ConAgra asserts that Fuller was aware of the dangers of lead dust solely in the occupational context. As we have already explained, the evidence supports the trial court's finding that Fuller was aware of the risks posed by lead paint on residential interiors. We reject ConAgra's challenge to the sufficiency of the evidence to support the trial court's express finding that Fuller was aware of the public health hazard to children posed by lead paint in residential interiors.
NL claims that the evidence was insufficient to support the trial court's actual knowledge finding because plaintiff was required to prove that NL had "knowledge in the early 1900s that children could get dangerous levels of blood lead from intact lead paint anywhere in any home ... via invisible dust." NL's claim is misleading. Our review of the trial court's actual *90 knowledge finding requires us to examine the record to determine whether there is substantial evidence that NL knew in the early 1900s that interior residential lead paint posed a significant risk of harm to children. We need not find evidence that NL understood precisely how children could be harmed by interior residential *534 lead paint so long as there is substantial evidence that NL knew that interior residential lead paint posed a significant risk of harm to children.
Our examination of the record reveals that it contains substantial evidence that NL had the requisite actual knowledge by 1914. The 1910 congressional hearing and the 1914 published speech were sufficient to make a leader in the lead paint industry aware of the risk of serious harm that interior residential lead paint posed to children. NL claims that there was not substantial evidence that it was aware in the early 20th century of the risks to children of "low-level" lead exposure. Since the information of which NL was aware suggested that even adults were at serious risk from interior residential lead paint, NL could not have failed to understand that the risk to children would be at least as great. NL, like Fuller, subsequently gained further knowledge, from its participation in the LIA, that children who ingested even very small amounts of lead could suffer serious harm. The LIA informed its members in the 1930s that even a small amount of lead could kill a child. And, at a 1937 LIA conference, a doctor informed LIA members that "[t]o get rid of the lead in children is almost impossible."
We find substantial evidence in the record to support the trial court's finding that NL had actual knowledge of the risk of harm to children from interior residential lead paint.
SWC claims that the trial court's finding that it had actual knowledge of the risk of harm to children from interior residential use of lead paint was based on "hindsight" because SWC could not have known "of today's alleged risk to children from ultra-low BLLs that can come from ingesting lead in household dust." SWC's premise is flawed. The trial court's actual knowledge finding may be upheld if there is substantial evidence that SWC was aware at the relevant time that interior residential lead paint posed a significant risk of harm to children. It was not necessary for there to be proof that SWC was aware of the precise pathway by which children were exposed to lead and or that those harms could occur even at low BLL levels, particularly since there was no BLL test in existence at the relevant time.
The evidence presented at trial established that SWC knew no later than 1900 that lead paint was prone to deterioration and that it posed a serious risk of harm to those exposed to it. SWC began making lead paint in 1880. By 1900, it knew that, because lead was a "deadly cumulative poison," and lead paint tended to deteriorate, lead paint could be seriously dangerous.
*91 SWC claims that its knowledge in 1900 of risks from deteriorating lead paint was limited to exterior use of lead paint, but the trial court could have reasonably concluded that SWC knew that the deterioration of interior residential lead paint would pose an even more serious risk that would be heightened with respect to young children who were necessarily confined to the interiors of their homes. We conclude that substantial evidence supports the trial court's finding that SWC had actual knowledge of the serious risk of harm to children from interior residential lead paint.
3. Creating or Assisting in Creating a Public Nuisance: Promotion
Defendants challenge the trial court's findings that they affirmatively promoted lead paint for interior residential use.
" '[T]he critical question is whether the defendant created or assisted in the creation of the nuisance. ' " ( Santa Clara I , supra , 137 Cal.App.4th at pp. 305-306, 40 Cal.Rptr.3d 313 .) "A public nuisance *535 cause of action is not premised on a defect in a product or a failure to warn but on affirmative conduct that assisted in the creation of a hazardous condition. Here, the alleged basis for defendants' liability for the public nuisance created by lead paint is their affirmative promotion of lead paint for interior use , not their mere manufacture and distribution of lead paint or their failure to warn of its hazards." ( Santa Clara I , at pp. 309-310 , 40 Cal.Rptr.3d 313 , italics added.)
Defendants claim that the court could not base its promotion findings on their advertising without violating the First Amendment. 30 They also contend *92 that reliance on the promotional advertising activities of the LIA and the NPVLA would violate their First Amendment right to free association. 31 In addition, the three defendants individually challenge the sufficiency of the evidence to support the court's findings that each of them affirmatively promoted lead paint for interior residential use.
Defendants' reliance on the First Amendment is misplaced. While "the creation and dissemination of information are speech within the meaning of the First Amendment" ( Sorrell v. IMS Health Inc. (2011) 564 U.S. 552 , 570, 131 S.Ct. 2653 , 180 L.Ed.2d 544 ), "[t]he Constitution ... accords a lesser protection to commercial speech than to other constitutionally guaranteed expression." ( Central Hudson Gas & Elec. Corp. v. Public Service Commission of New York (1980) 447 U.S. 557 , 562-563, 100 S.Ct. 2343 , 65 L.Ed.2d 341 ( Central Hudson ).) "[T]here can be no constitutional objection to the suppression of commercial messages that do not accurately inform the public about lawful activity. The government may ban forms of communication more likely to deceive the public than to inform it, [citations], or commercial speech related to illegal activity, [citation]." 32 ( Central Hudson , at pp. 563-564, 100 S.Ct. 2343 .)
*536 "[T]he State does not lose its power to regulate commercial activity deemed harmful to the public whenever speech is a component of that activity." ( Ohralik v. Ohio State Bar Ass'n (1978) 436 U.S. 447 , 456, 98 S.Ct. 1912 , 56 L.Ed.2d 444 .) The California Supreme Court has already acknowledged that holding defendants liable in this case for the public nuisance created by their promotion of lead paint for interior residential use will not "prevent defendants from exercising any First Amendment right or any other liberty interest. Although liability may be based in part on prior commercial speech, the remedy will not involve enjoining current or future speech." ( Santa Clara II , supra , 50 Cal.4th at p. 55 , 112 Cal.Rptr.3d 697 , 235 P.3d 21 ; see also People v. Superior Court (Olson) (1979) 96 Cal.App.3d 181 , 195, 157 Cal.Rptr. 628 [imposing civil "penalties for the negligent dissemination of untruthful or misleading advertising does not offend the First Amendment."].)
Defendants' lead paint promotional advertising and participation in trade-association-sponsored lead paint promotional advertising were not entitled to *93 any First Amendment protections. Promotion of lead paint for interior residential use necessarily implied that lead paint was safe for such use. If defendants promoted lead paint for interior residential use while knowing that such use would create a public health hazard, then their promotions were misleading and not entitled to any First Amendment protection. If, on the other hand, defendants did not promote lead paint for interior residential use, or did not know at the time they did so that such use would create a public health hazard, those promotions would not establish that defendants created or assisted in the creation of a public nuisance. As any wrongful promotions would be misleading and not entitled to First Amendment protection, we find no First Amendment bar to the trial court's reliance on defendants' promotions.
Defendants also make individual challenges to the sufficiency of the evidence to support the trial court's findings that each of them affirmatively promoted lead paint for interior residential use while knowing of the public health hazard that such use would create. Our review of these contentions requires us to examine, among other things, the hundreds of advertisements upon which plaintiff relied to show that defendants had promoted lead paint for interior residential use. We must note at the outset that, for a number of reasons, a large number of these advertisements did not promote interior residential use of lead paint.
Some of these advertisements expressly promoted only exterior use of lead paint. Others promoted a particular brand without specifying any particular paint. Numerous advertisements promoted lead paint as "house paint" without expressly promoting it for interior use.
Another group of these advertisements promoted interior use of a particular paint without identifying that paint as a lead paint, and without other evidence that the particular paint promoted for interior use in these advertisements was a lead paint. Stipulations between plaintiff and NL and between plaintiff and SWC established that certain paints promoted by NL and *537 SWC were lead paints, but there was no such stipulation with regard to Fuller or as to paint companies acquired by NL or SWC. And many of the advertisements were not specific enough to identify the promoted paint as one of those identified in the stipulations.
Many of the advertisements were not placed by NL, SWC, or Fuller, but instead by a paint store or a hardware retailer. While there was evidence that SWC financed half of the cost of its authorized dealers' local advertisements and that NL "consistently supported dealers' local advertising," plaintiff's expert acknowledged that there was no such evidence as to Fuller. As there was no evidence that Fuller had any involvement in the placement of *94 advertisements by hardware and paint stores, advertisements by those stores cannot be attributed to Fuller and cannot show that Fuller promoted lead paint for interior residential use. 33
Plaintiff also relied on the LIA's two promotional campaigns. The member companies that participated in these campaigns funded them. Fuller was a member of the LIA from 1928 to 1958. SWC was a member of the LIA from 1928 to 1947. NL was an LIA member from 1928 to 1978. NL and Fuller participated in both of the LIA's campaigns; SWC participated in only the Forest Products campaign and contributed funds to that campaign only from 1937 to 1941.
Because the LIA's promotional campaigns affected multiple defendants, we detail those campaigns at the outset. The Forest Products campaign, which ran from 1934 to 1941, was aimed at having manufacturers of lumber, window frames, and doors endorse lead paint. The purpose of the Forest Products campaign, which was active in California, was to promote the use of lead paint on lumber and in residences. In 1934, the LIA persuaded lumber manufacturers associations on the West Coast to recommend the use of lead paint on lumber by "enclos[ing] 'Painting Instructions' folders with all bundles of siding" in 1935. 34 In 1938, the LIA persuaded the Western Pine Association to paint its model home at the San Francisco World's Fair "inside and out with white lead and publicize this specification." Also in 1938, the LIA persuaded "sash [ (window frame) ] and door manufacturers" to put labels on 20,000,000 sashes and doors "featuring the use of white lead and high-grade prepared paint." In 1939, the LIA board was apprised that, due to the Forest Products campaign, " '[a]ll of the principal producers of soft and hard lumber in the United States such as redwood, cypresses, cedar, pine and others, now specify white lead or high grade prepared paint which contain white lead.' "
*538 The LIA's White Lead Promotion campaign, which ran in two phases, phase one from 1939 to 1944 and phase two from 1950 through 1952, was *95 intended to increase the market for white lead. 35 This campaign produced hundreds of advertisements promoting white lead. LIA advertisements in 1939 and 1940 expressly promoted lead paint for interior residential use. A 1939 LIA advertisement in the Hardware Retailer reproduced a letter to the LIA from the Douglas Fir Plywood Association touting lead paint for interior walls and ceilings in addition to "exterior siding." In 1940, LIA advertisements in "National Painters Magazine" and "American Painter and Decorator" promoted interior residential use of lead paint and proclaimed such things as "white lead lends itself ideally to any paint styling desired by owner or architect, inside or out." 1940 LIA advertisements in American Paint and Oil Dealer, American Painter and Decorator, National Painters Magazine, The Painter and Decorator, American Builder, Hardware Retailer, and Hardware Age all promoted lead paint for interior residential use.
By 1941, the LIA's campaigns had created a great increase in the sale of lead paint compared to non-lead paint. During the war, lead paint sales declined, and they continued to decline after the war. The LIA briefly revived the White Lead Promotion campaign in the early 1950s, but it subsequently stopped specifically promoting white lead paint. Although the LIA's campaigns did not reverse the long-term trend of less use of lead pigments, these campaigns did prolong the use of lead pigments that otherwise probably would have ceased to be used. 36 More white lead was used during the Depression (the late 1920s and 1930s) than had been used previously, and the LIA attributed this increase to its campaigns.
With this background in mind, we proceed to review defendants' individual contentions.
a. ConAgra
ConAgra contends that there is not substantial evidence that Fuller promoted lead paint for residential interiors with the requisite knowledge because (1) Fuller's post-1929 advertisements did not tell consumers to use lead paint on residential interiors, (2) Fuller's post-1935 advertisements did not mention lead or were only for exterior paint, (3) Fuller did not sell any lead paint for interiors after 1948, and (4) Fuller did not participate in the LIA's promotions.
Evidence at trial established that Fuller sold lead paint in the 10 jurisdictions from 1894 to 1961. Between 1894 and 1948, Fuller marketed two lead *96 products: Pure Prepared Paint and Pioneer White Lead in Oil. 37 Fuller also marketed paints and other coatings that did not contain lead. Fuller's lead paints were sold at its own stores and by independent dealers in all 10 jurisdictions between 1894 and 1961. Plaintiff's experts testified that Fuller promoted the use of white lead by distributing brochures for consumers and painters that instructed them to use Fuller's lead paints for residential interiors and exteriors. They also asserted that Fuller's advertisements in the 10 jurisdictions instructed consumers *539 to use Fuller's white lead paints on their residences.
A large number of the advertisements for Fuller products in the record are not for Fuller's lead paint but for other Fuller paints or coatings. 38 Another group of these advertisements simply generally advertised Fuller paints with no specification of which ones or without specifying for what purposes, or with specifications of the purposes for each paint that did not suggest that Fuller's lead paint be used for interiors. Plaintiff's expert testified: "In my expert opinion, they all are advertising Fuller Paints which contain lead. And they are actually ads that are informing consumers to use Fuller products without any acknowledgment they are containing lead. Some of them have lead in it, some don't." Since plaintiff's expert acknowledged that Fuller made both lead paint and non-lead paint, the mere fact that Fuller advertised its products does not establish that it promoted its lead paint for interior residential use. We disregard plaintiff's expert's testimony on this point because it lacks any rational basis in the evidence.
Many advertisements in the record were for Fuller's lead paint but did not expressly suggest that it be used for interiors. Some of these advertisements described Fuller's lead paint as "house paint." However, another group of Fuller advertisements explicitly promoted Fuller's lead paints for "all" residential purposes. For example, a 1927 Monterey Fuller advertisement promoted Fuller's lead paint "for all general purposes." Fuller advertisements in 1937 in the San Francisco Chronicle and the Los Angeles Times described Fuller's lead paint as "all purpose, 'house' paint." While these advertisements suggested that Fuller's lead paint could be used for any purpose, including interior residential use, the most important evidence of Fuller's promotion of its lead paint for interior residential use was Fuller's 1931 brochure for its lead paint. This brochure's "Directions for Use" instructed consumers to use this lead paint for residential interiors. Since Fuller's advertisements frequently suggested that consumers obtain brochures from a Fuller dealer, the *97 brochure's "Directions for Use" amounted to instructions to all of those who purchased Fuller's lead paint to use it for residential interiors. Fuller also participated in both of the LIA's promotional campaigns in the 1930s and 1940s, which promoted lead paint for interior residential use.
This evidence rebuts ConAgra's contentions. Fuller did promote its lead paint after 1929 and after 1935, both by instructing consumers to use its lead paint for interior residential use and by participating in the LIA's campaigns promoting lead paint for interior residential use. It is immaterial whether Fuller's advertisements mentioned the word "lead" so long as the paint promoted in the advertisement was a lead paint, as it was. Fuller's claim that it ceased to produce and sell lead paint in 1948 is immaterial even if true. It was not necessary to show that Fuller continued to assist in the creation of the public nuisance throughout the entire period if its conduct constituted a substantial factor in causing the public nuisance (an issue we address in section IV(A)(4) of this opinion). Fuller's claim that it did not participate in the LIA's promotions was rebutted by substantial evidence at trial.
We conclude that there is substantial evidence that Fuller itself promoted its *540 lead paint for interior residential use at least beginning in 1931 and that it continued to do so as part of the LIA's promotional campaigns in the 1930s and 1940s. Since the evidence supports the trial court's finding that Fuller knew of the danger that such use would create for children at that time, there is substantial evidence that Fuller promoted lead paint for interior residential use with the requisite knowledge.
b. NL
NL contends that its advertisements were not misleading because they merely described how well lead paint would protect and beautify interior walls and woodwork. As we have already explained, promotion of lead paint for interior residential use was inherently misleading because it implicitly asserted that it was safe for such use when it was not. NL also asserts that the court's promotion finding cannot be upheld because there was no evidence that NL promoted lead paint for interior residential use after 1950. As we have noted above, the period during which a defendant assisted in the creation of a public nuisance is relevant only as to causation; it does not rebut a showing of affirmative promotion with the requisite knowledge.
Substantial evidence supports the trial court's finding that NL affirmatively promoted lead paint for interior residential use with the requisite knowledge. NL stipulated that it manufactured, sold, and promoted lead paint for residential use in the 10 jurisdictions from 1900 to 1972 and that its "White Lead-in-Oil," "Dutch Boy House Paint 104," "Dutch Boy House Paint 111,"
*98 and "Dutch Boy House Paint 116" contained white lead. No evidence was produced at trial that any other NL paint products contained white lead. 39
Plaintiff's expert testified that NL promoted its Dutch Boy lead paint for interior residential use. NL produced "little illustrated books [in which] children were provided with both a story and a coloring pallet of paint that basically depicted the ways in which Dutch Boy white lead paint protected children from all sorts of onslaughts." He testified that NL "[s]pecifically promoted the use" of lead paint in "play rooms, ... homes and on to surfaces and even on their furniture." Plaintiff's expert also noted that NL's advertisements did not necessarily disclose whether NL's lead paint contained lead and did not always distinguish between the use of lead paint on interiors and its use on exteriors. As we will explain, the material upon which plaintiff's expert based his testimony provides substantial support for his testimony.
NL's advertisements from the early 20th century demonstrate that NL repeatedly promoted its lead paint for interior residential *541 use. A 1915 NL advertisement in the San Francisco Chronicle did so. A 1924 NL advertisement in National Geographic Magazine did so. A 1929 NL advertisement in the Los Angeles Times did so. 1929 NL advertisements in the San Francisco Chronicle and the Oakland Tribune promoted lead paint for "your stucco house or for any other surface ." (Italics added.) A 1938 San Diego advertisement by a paint store promoted Dutch Boy, NL's brand, as "All Purpose Lead." A 1950 San Diego advertisement by a paint store promoted NL's lead products for interior residential use. And NL participated in both of the LIA's promotional campaigns in the 1930s and 1940s promoting lead paint for interior residential use.
NL's 1929 "paint book" for children showed a "Dutch Boy Painter" who tells the children, "This famous Dutch Boy Lead of mine [¶] Can make this playroom fairly shine [¶] Let's start our painting right away [¶] You'll find the work is only play." The book showed children stirring and painting with clearly labeled containers of Dutch Boy White Lead paint and then playing in *99 their newly painted playroom. At the end of the book, it said: "For durable economical paint-inside or outside [¶] Paint with lead [¶] Dutch Boy White-Lead." Every page of the "paint book" instructed children to give their parents the "coupon" in the middle of the book. 40 NL's paint book contained "paper chips of paint" for children to use to color the pictures in the book. NL used this paint book as a promotion "for many years." This paint book obviously promoted lead paint for interior residential use.
NL's 1949 salesman's manual instructed NL's salesmen that NL's lead paints could "handle any painting job, exterior or interior" on any building. The manual told the salesmen that NL's "Lead Mixing Oil" was appropriate for "interior surfaces."
NL's 1950 "Handbook on Painting" encouraged the use of white lead paint on interior surfaces: "On interiors white lead is desired for its unique richness and solid beauty of finish. Also, the durability of white lead paint enables it to stand up under frequent washing-a big money saver in such places as hospitals and hotels." "The customary flat paint for interior work is made by mixing white lead with either Lead Mixing Oil or flatting oil." "Dutch Boy Lead Mixing Oil, when mixed with white lead in the proper proportions, makes flat paint that can be used on exterior as well as interior surfaces." "Furthermore, white lead and Lead Mixing Oil has the sturdy wear and beauty of finish characteristic of all white lead paint, whether exposed to weather or used inside. [¶] White lead and Lead Mixing Oil can be used for all coats on plaster and wallboard." NL's instructions for use in this handbook explicitly advocated the use of lead paint on interiors.
Substantial evidence supports the trial court's finding that NL affirmatively promoted lead paint for interior residential use with the requisite knowledge. NL extensively promoted its lead paint for interior residential use from 1915 through 1950. Because NL knew of the danger to children from lead paint on residential interiors no later than 1914, substantial evidence supports the trial court's finding that NL's subsequent promotions of lead paint for such use were done with the requisite knowledge.
c. SWC
SWC contends that plaintiff did not present evidence of any advertisement *542 by SWC promoting lead paint for interior residential use.
SWC stipulated that it began manufacturing lead paint in 1880 and began manufacturing white lead carbonate pigment in 1910. SWC manufactured *100 Old Dutch Process (ODP) white lead in oil from 1910 to 1947. SWC manufactured "Inside Floor Paint," some colors of which contained white lead, between 1910 and 1913. SWC's other white lead paints were some of its SWP "house paint" colors until 1950, some of its "Family Paint" colors in the 1940s, 41 its "Porch and Deck" paint, and its "Concrete & Stucco" paint. 42 SWC also sold Monarch House Paint, ACME Quality House Paint, and Lowe Brothers High Standard House Paint, which were all lead paints. In a 1934 promotional booklet, SWC proclaimed that it was the "world's largest paint producer" and "one of the country's largest producers of White Lead."
SWC promoted and sold its white lead products for residential use in the 10 jurisdictions. The primary message conveyed in advertisements for SWC's paints, Monarch paints, and ACME's paints was that there was a specific coating for each purpose and that it was important to get the right coating for each type of use. For example, a 1903 SWC advertisement read: "No matter what you want to paint, ... you'll get best results and save money if you use [¶] THE SHERWIN-WILLIAMS PAINTS [¶] A special paint for each purpose." A large group of SWC advertisements simply generically advertised SWC's brand, without specifying any particular paints. Many SWC advertisements were for SWC's non-lead "Kemtone" paint.
Advertisements for SWC's SWP House Paint often specified that it was for exterior use. Others simply referred to SWP as "house paint" without mentioning interior use. Still others identified SWP as being for "wood surfaces" or for all "woodwork" surfaces. However, there were also advertisements promoting SWP for interior residential use. 1904 SWC advertisements in the Los Angeles Times and the San Diego Union promoted SWP for "inside" use. 43 In addition, SWC participated in the LIA's Forest Products *101 campaign from 1937 to *543 1941, which promoted lead paint for interior residential use and particularly for use on doors and window frames.
SWC had the requisite knowledge in 1900 of the public health hazard posed by lead paint, but it nevertheless continued to promote lead paint for interior residential use thereafter. This evidence supports the trial court's finding that SWC engaged in the requisite wrongful promotion.
4. Causation
Defendants contend that plaintiff did not produce substantial evidence that their promotions of lead paint for interior residential use were a substantial factor in causing the nuisance that the trial court required them to abate. First, they contend that there was no evidence that their promotions actually had an impact on the use of lead paint on residential interiors. Second, they contend that their wrongful promotions were too remote from the current presence of any public health hazard created by interior residential lead paint, which, they claim, is largely due to owner neglect, renovations, intervening actors (architects, painters, etc.), and repainting that has taken place in the interim. Third, they argue that, because they did not promote lead paint for interior residential use after 1950, they could not be held responsible for use of lead paint on residential interiors of homes built after 1950. The trial court's judgment required defendants to remediate interior lead paint in all homes built before 1980, even though most of those homes were built after 1950. Fourth, they maintain that there was no evidence that their promotions of lead paint for interior residential use had a causal connection to the water leaks and soil lead that the court ordered them to remediate. Fifth, defendants claim that plaintiff was required to show that their individual lead paints are currently present in a large number of homes in the 10 jurisdictions. Sixth, they argue that due process requires that their liability for remediation be proportionate to their individual contributions.
Causation is an element of a cause of action for public nuisance. ( Melton v. Boustred (2010) 183 Cal.App.4th 521 , 542, 107 Cal.Rptr.3d 481 .) "A connecting element to the prohibited harm must be shown." ( In re Firearm Cases (2005) 126 Cal.App.4th 959 , 988, 24 Cal.Rptr.3d 659 ( Firearm Cases ).) The parties agree that the causation element of a public nuisance cause of action is satisfied if the conduct of a defendant is a substantial factor in bringing about the result. ( Citizens for Odor Nuisance Abatement v. City of San Diego (2017) 8 Cal.App.5th 350 , 359, 213 Cal.Rptr.3d 538 [applying *102 substantial factor standard in a public nuisance action].) " 'The substantial factor standard is a relatively broad one, requiring only that the contribution of the individual cause be more than negligible or theoretical.' [Citation.] Thus, 'a force which plays only an "infinitesimal" or "theoretical" part in bringing about injury, damage, or loss is not a substantial factor' [citation], but a very minor force that does cause harm is a substantial factor [citation]." ( Bockrath v. Aldrich Chemical Co., Inc. (1999) 21 Cal.4th 71 , 79, 86 Cal.Rptr.2d 846 , 980 P.2d 398 .)
a. Impact and Remoteness
In this case, there was plenty of evidence that defendants' affirmative promotions of lead paint for interior residential use played at least a "minor" role in creating the nuisance that now exists.
First, all three defendants participated in the LIA's Forest Products campaign. The Forest Products campaign began in 1934. In 1935, the LIA reported that its Forest Products campaign had resulted in *544 some manufacturers of leadless paints "changing their formulas to include lead." In 1939, the LIA reported to its members that, as a result of the Forest Products campaign, (1) "[a]ll the principal producers of soft and hard lumber in the United States ... specify white lead or high grade prepared paint which contains white lead" through the "distributi[on of] painting instruction leaflets (2,000,000 copies)"; (2) "[s]ome paint companies have increased the lead content of their paint"; and (3) "sash and door manufacturers" would be producing "20,000,000 labels to be affixed to nearly all the sash and doors in the United States, featuring the use of white lead and high-grade prepared paint." In 1941, the LIA reported that the benefits of the Forest Products campaign were continuing. "Lumber associations continued distributing, at their own expense, thousands of painting leaflets recommending white lead or the highest grade prepared paints to be used on their products" and that the "National Door Manufacturing Association" was "the latest to use painting leaflets" to promote the use of white lead. The lumber manufacturers were continuing to include "painting instruction leaflets" with their lumber products. Since lead paint on doors and windows is one of the most hazardous uses for children due to the dust created by their friction surfaces, this campaign played a significant role in creating the nuisance that now exists.
Second, both NL and Fuller gave consumers of their lead paints explicit instructions to use those paints on residential interiors. Fuller's 1931 brochure for its lead paint contained "Directions for Use" instructing consumers to use this lead paint for residential interiors. Since Fuller's advertisements frequently suggested that consumers obtain brochures from a Fuller dealer, the brochure's "Directions for Use" constituted instructions to all those who *103 purchased Fuller's lead paint to use it for residential interiors. NL produced its 1929 paint book, which promoted lead paint for interior residential use, and NL published its 1950 "Handbook on Painting," which explicitly recommended that consumers use white lead paint on interior surfaces.
In sum, by persuading window and door manufacturers to attach written recommendations to all windows and doors that lead paint should be used on those windows and doors, all three defendants certainly played a significant role in causing lead paint to be used on at least some of those windows and doors. Further, NL and Fuller, by explicitly instructing consumers to use their lead paints on residential interiors, played an even more direct role in causing lead paint to be used in such a manner. Again, the trial court could reasonably infer that at least some of those who were the targets of these recommendations heeded them. That is all that the substantial factor test requires.
We cannot credit defendants' claim that there was no evidence that their promotions were even "a very minor force"-"a substantial factor"-in causing the presence of lead paint on residential interiors in the 10 jurisdictions. The LIA's extensive advertising campaigns, in which all three defendants participated, affirmatively promoted to painters, architects, retailers, and consumers the use of lead paint on residential interiors, and each defendant also individually promoted to consumers lead paint for use on residential interiors in the 10 jurisdictions. The LIA judged its promotional campaigns to be a success, and the fact that lead paint remains in place on residential interiors in many homes throughout the 10 jurisdictions decades after all of these promotions ceased reflects that this belief was accurate. We find reasonable the inference that each individual *545 defendant's promotion of lead paint for interior residential use, both through the LIA promotional campaigns and their individual promotions, were at least "a very minor force" in leading to the current presence of interior residential lead paint in a substantial number of homes in the 10 jurisdictions.
Defendants also contend that their wrongful promotions were too remote from the current hazard to be its "legal cause." They claim that, due to the lapse of time, this hazard is more closely attributable to owner neglect, renovations, painters, architects, and repainting. "A tort is a legal cause of injury only when it is a substantial factor in producing the injury." ( Soule v. General Motors Corp. (1994) 8 Cal.4th 548 , 572, 34 Cal.Rptr.2d 607 , 882 P.2d 298 .) " ' " 'Legal cause' exists if the actor's conduct is a 'substantial factor' in bringing about the harm and there is no rule of law relieving the actor from liability. [Citations.]" ' [Citations.] ' "The doctrine of proximate cause limits liability; i.e., in certain situations where the defendant's conduct is an actual cause of the harm, he will nevertheless be absolved because of the manner in which the injury occurred." ' " ( Lombardo v. Huysentruyt (2001) 91 Cal.App.4th 656 , 665-666, 110 Cal.Rptr.2d 691 .)
*104 " 'Proximate cause involves two elements.' [Citation.] 'One is cause in fact . An act is a cause in fact if it is a necessary antecedent of an event.' [Citation.] ... [¶] By contrast, the second element focuses on public policy considerations. Because the purported causes of an event may be traced back to the dawn of humanity, the law has imposed additional 'limitations on liability other than simple causality.' [Citation.] 'These additional limitations are related not only to the degree of connection between the conduct and the injury, but also with public policy.' [Citation.] Thus, 'proximate cause' "is ordinarily concerned, not with the fact of causation, but with the various considerations of policy that limit an actor's responsibility for the consequences of his conduct." ' " ( Ferguson v. Lieff, Cabraser, Heimann & Bernstein (2003) 30 Cal.4th 1037 , 1045, 135 Cal.Rptr.2d 46 , 69 P.3d 965 .) "[T]here is no bright line demarcating a legally sufficient proximate cause from one that is too remote. Ordinarily the question will be for the [factfinder], though in some instances undisputed evidence may reveal a cause so remote that a court may properly decide that no rational trier of fact could find the needed nexus." ( People v. Roberts (1992) 2 Cal.4th 271 , 320, fn. 11, 6 Cal.Rptr.2d 276 , 826 P.2d 274 .)
Defendants argue that they should be absolved of responsibility for the current hazard because their wrongful conduct was "too remote" and "attenuated" from the current hazard. 44 This was a question of fact for the trial court. A rational factfinder could have concluded that defendants' wrongful promotions of lead paint for interior residential use were not unduly remote from the presence of interior residential lead paint placed on those *546 residences during the period of defendants' wrongful promotions and within a reasonable period thereafter. The connection between the long-ago promotions and the current presence of lead paint was not particularly attenuated. Those who were influenced by the promotions to use lead paint on residential interiors in the 10 jurisdictions were the single conduit between defendants' actions and the current hazard. Under these circumstances, the trial court could have reasonably concluded that defendants' promotions, which were a substantial factor in creating the current hazard, were not too remote to be considered a legal cause of the current hazard even if the actions of others in response to those promotions and the passive neglect of owners also played a causal role. The court could therefore have concluded that defendants' promotions were the "legal cause" of the current nuisance. *105 b. Post-1950 Homes
We find merit in defendants' claim that the record lacks substantial evidence to support the court's finding that their wrongful promotions were causally connected to post-1950 homes containing interior lead paint built before 1980.
Plaintiff claims that defendants' wrongful promotions "sustained, increased, and prolonged the use of lead paint in homes throughout the 20th century ." (Italics added.) It asserts that this can be "inferred" from the "sheer breadth of Defendants' promotional activities" and the fact that there is currently lead paint in homes in the 10 jurisdictions. Plaintiff also claims that NL continued to promote lead paint for interior residential use beyond 1950.
First of all, plaintiff did not produce any evidence of an affirmative promotion by NL, SWC, or Fuller of lead paint for interior residential use after 1950. The advertisements that plaintiff identifies as post-1950 NL promotions did not promote lead paint for interior residential use. Those advertisements promoted NL's "Dutch Boy" brand of paints and identified interior residential use as one of the uses for NL's "Dutch Boy" brand of paints without suggesting that any lead paint be used for interiors. NL stipulated at trial that its "White Lead-in-Oil" and three of its "Dutch Boy" paints contained white lead, and plaintiff presented no evidence that any other NL paint product contained lead. Since NL indisputably made many Dutch Boy paints, NL's promotion of its brand for many uses, including interior residential use, did not amount to an affirmative promotion of lead paint for interior residential use. Indeed, plaintiff's argument seems to be based on the idea that the mere fact that these advertisements identified National Lead Company as the maker of Dutch Boy paints transformed advertisements for non-lead paints for interior use into promotions of lead paint for interior use. We reject this unfounded argument.
NL contends that the evidence could not support a finding that it caused the use of lead paint on residential interiors after 1955 because, according to NL, all lead paint bore a label marking it as not for interior residential use beginning in 1955. The only citation to the record that NL provides is to testimony by a defense expert about a standard created by the American Standards Association in 1955. The expert testified that the LIA had participated in the creation of that standard. He referenced a defense exhibit, a barely legible copy of which appears in the record, that apparently contains the 1955 standard. This standard states: "These specifications cover the requirements for coatings (such as paints, enamels, lacquers, etc. applied in liquid form) which are deemed suitable from a health standpoint *547 to be used to paint children's toys or furniture or interior surfaces so that the danger of *106 poisoning will be minimized if, by chance, some of this coating should be chewed off and swallowed by a child." "A liquid coating material to be deemed suitable, from a health standpoint, for use on articles such as furniture, toys, etc., or for interior use in dwelling units where it might be chewed by children" should not contain more than 1 percent lead. The standard states that coatings complying with it "may be marked: 'Conforms to American Standard Z66.1-1955, for use on surfaces that might be chewed by children." Notably, this standard does not impose any labeling requirement of any kind on lead paint.
Although one might draw an inference that the LIA's participation in the creation of this standard encouraged the compliance of its members, the trial court was not required to draw that inference. Indeed, the standard itself stated: "The existence of an American Standard does not in any respect preclude any party who has approved of the standard from manufacturing, selling, or using products ... not conforming to the standard." Moreover, this standard did not even suggest a label for lead paint. It pertained to a label for non- lead paints. Nor is there any affirmative evidence in the record that even this standard was enforced by anyone or that any defendant complied with it beginning in 1955.
Nevertheless, plaintiff's assertion that the current presence of lead paint on residential interiors itself establishes that defendants' pre-1951 promotions caused it to be placed there is speculative and attempts to eliminate the causation element entirely. While we can accept the inference that defendants' pre-1951 promotions increased the use of lead paint on residential interiors during the period of those promotions, we reject plaintiff's claim that it is a reasonable inference that the impact of those promotions may be assumed to have continued for the next 30 years. We can find no evidence in the record that supports an inference that the promotions of defendants prior to 1951 continued to cause the use of lead paint on residential interiors decades later. 45 We therefore conclude that we cannot uphold the trial court's judgment requiring defendants to remediate all houses built before 1981 because there is no evidence to support causation as to the homes built after 1950. 46
*107 c. Water Leaks and Soil Lead
Defendants also challenge on causation grounds the court's inclusion of soil lead and water leaks in its remediation plan.
This was a disputed issue at trial. Plaintiff's experts testified: "[L]ead paint gets into the soil from several routes. One is by the friction and impact surfaces, opening and closing windows and doors on a home with lead-based paint. It also results from the weathering of paint exterior on the home, rain and sun hits the paint, it *548 deteriorates over time. And also previous paint jobs, generally where they are sanding and scraping have contributed to soil lead contamination around the home." Lead concentrations are highest close to the home "[b]ecause we know that the exterior is subject to weathering, because windows on the exterior often have high lead concentrations and they are subject to friction and impact, and because the previous painting jobs could have caused sanding and scraping on the exterior of a home which often then resides as contamination of the soil close to the home." 47 "[L]ead-based paint in housing now is the major source of contamination of both soil and house dust." 48 Thus, plaintiff's evidence established that a prime contributor to soil lead was lead paint on the friction surfaces of windows and doors, which are interior, rather than exterior surfaces. In keeping with this evidence, the judgment requires remediation of soil lead only where the home itself contains interior lead paint. Under these circumstances, the evidence supports the court's implied finding that soil lead in those homes has been caused by interior residential use of lead paint.
The court's decision to include remediation of water leaks in the judgment is not a causation issue. Plaintiff did not contend that the water leaks should be remediated because they were caused by defendants' promotions. The reason why remediation of water leaks is properly part of the remediation plan is that the court did not order remediation of all interior lead paint. As water leaks could cause intact interior lead paint to deteriorate and present a dangerous hazard to children, the remediation of water leaks was an appropriate lesser alternative to removal of all interior lead paint. Since defendants' wrongful promotions caused the presence of interior lead paint, the court did not err in requiring remediation designed to prevent that interior lead paint from harming children in those homes.
*108 d. Identification of Individual Paint
Defendants contend that their promotions cannot be found to have caused the presence of interior lead paint in homes in the 10 jurisdictions without proof that paint made by each of them is currently present in those homes. This contention misconstrues the basis for defendants' liability. Defendants are liable for promoting lead paint for interior residential use. To the extent that this promotion caused lead paint to be used on residential interiors, the identity of the manufacturer of that lead paint is irrelevant. Indeed, the LIA's promotions did not refer to any manufacturer of lead paint, but were generic. What matters is whether defendants' promotions were a substantial factor in leading to the use of lead paint on residential interiors. Substantial evidence supports the court's causation finding on that basis.
e. Proportioned Liability
Defendants' final challenge to the court's causation finding is based on their claim that they could not be held liable *549 except in proportion to their individual contributions to the creation of the public nuisance. They claim that due process precluded the imposition of a remedy that was "grossly disproportionate to a defendant's conduct."
None of the cases they cite concerns causation in a public nuisance case. Proportionality is not a causation issue. Defendants may be held liable for a public nuisance that they assisted in creating if their wrongful promotions were a substantial factor in the creation of that public nuisance. As we have already concluded, the evidence supports the trial court's finding at least as to homes built before 1951. Proportionate liability is something that defendants may be able to determine by means of litigation between themselves, but the fact that the remediation plan does not apportion liability among defendants does not infect the court's causation finding.
Citing the Restatement, defendants argue that "a defendant can be liable only for its own contribution to a nuisance." However, the Restatement comment upon which they rely does not support their contention. It says: "[T]he burden rests upon the defendant to produce sufficient evidence to permit the apportionment to be made. [¶] When the apportionment is made, each person contributing to the nuisance is subject to liability only for his own contribution. He is not liable for that of others; but the fact that the others are contributing is not a defense to his own liability." ( Rest.2d Torts, § 840E, com. B, italics added.) The trial court could have reasonably concluded that defendants did not prove that the harm was capable of apportionment. The Restatement confirms that where the harm is not capable of apportionment, each contributor is liable for the entire harm. ( *109 Rest.2d Torts, § 840E, com. c.) In this case, it is clear that the trial court properly concluded that the harm was incapable of apportionment and therefore held all three defendants jointly and severally liable for the entire harm.
5. Abatability, Imminent Danger, and Reduction of BLLs
Defendants contend that plaintiff failed to prove that defendants have the ability to abate lead in private homes or that abatement can be achieved "at a reasonable cost by reasonable means."
This court rejected defendants' "ability to abate" contention in Santa Clara I . " '[L]iability for nuisance does not hinge on whether the defendant owns, possesses or controls the property, nor on whether he is in a position to abate the nuisance; the critical question is whether the defendant created or assisted in the creation of the nuisance. ' " ( Santa Clara I , supra , 137 Cal.App.4th at p. 306 , 40 Cal.Rptr.3d 313 .) We decline to reconsider this issue. 49
Defendants' "reasonable cost" contention is premised on Mangini v. Aerojet-General Corp. (1996) 12 Cal.4th 1087 , 51 Cal.Rptr.2d 272 , 912 P.2d 1220 ( Mangini II ). The issue in Mangini II concerned the statute of limitations. ( Mangini II , at p. 1090, 51 Cal.Rptr.2d 272 , 912 P.2d 1220 .) Because the plaintiffs had not filed their private nuisance action within the three-year limitations period for a "permanent" nuisance, the action was barred unless the nuisance was a "continuing" one. ( Ibid. )
*550 " '[T]he crucial test of the permanency of a trespass or nuisance is whether the trespass or nuisance can be discontinued or abated.' " ( Mangini II , at p. 1097, 51 Cal.Rptr.2d 272 , 912 P.2d 1220 .) The California Supreme Court held that the plaintiffs had failed to prove that the nuisance was abatable. However, the court expressly denied that its holding would be applicable where the statute of limitations was not at issue: "We express no opinion on the question whether a plaintiff who has filed a timely nuisance action is required to prove that abatement can be accomplished at a 'reasonable cost' in order to be entitled to an injunction requiring the wrongdoing party to remedy the damage to the property." ( Mangini II , at p. 1090, 51 Cal.Rptr.2d 272 , 912 P.2d 1220 .) Defendants choose to ignore this statement, but it establishes that Mangini II provides no support for their claim. 50
Defendants' reliance on County of San Diego v. Carlstrom (1961) 196 Cal.App.2d 485 , 16 Cal.Rptr. 667 ( Carlstrom ) is also misplaced. Carlstrom *110 was a case in which the defendants claimed that the abatement injunction should have offered them abatement options other than removal of the structures that the court had found to be a public nuisance. ( Carlstrom , at p. 493, 16 Cal.Rptr. 667 .) The Court of Appeal found that the trial court had not abused its discretion in requiring removal. ( Ibid. ) We can find nothing in Carlstrom to support defendants' abatability or reasonable cost contentions.
Defendants assert that plaintiff failed to establish that lead paint poses an imminent danger of harm and that the abatement plan will reduce children's BLLs. Plaintiff responds that it presented substantial evidence that lead paint poses an imminent risk of harm and that abatement, and particularly door and window replacement, will reduce the number of children who are poisoned by lead paint.
Defendants rely on Helix Land Co. v. City of San Diego (1978) 82 Cal.App.3d 932 , 147 Cal.Rptr. 683 ( Helix ) to support their claim that plaintiff failed to prove that lead paint poses an imminent danger of harm. The plaintiff in Helix attempted to allege inverse condemnation and nuisance causes of action based on its claim that its land was at greater risk of harm due to the City's actions and inactions regarding flood control. ( Helix , at pp. 940, 950, 147 Cal.Rptr. 683 .) However, the plaintiff failed to allege that the City's actions "present[ ] a future hazard" to its land. ( Helix , at p. 950, 147 Cal.Rptr. 683 .) The plaintiff did not allege that any damage had occurred, and the court found that it was mere speculation that damage might occur in the future. ( Ibid . ) The court rejected the plaintiff's nuisance cause of action on the ground that it had failed to allege that a "prospective nuisance" was "either probable or imminent." ( Helix , at p. 951, 147 Cal.Rptr. 683 .)
Helix does not support defendants' challenge to the trial court's abatement order. In this case, unlike in Helix , there was substantial evidence that interior residential lead paint had been causing and will continue to cause harm to children in the 10 jurisdictions. 51 "Almost all human activity involves some risk, and in circumstances *551 in which Civil Code section 3479 is the only applicable statute, considerable judicial discretion has been allowed in determining whether an alleged danger is sufficiently serious to justify abatement." ( City of Bakersfield v. Miller (1966) 64 Cal.2d 93 , 99, 48 Cal.Rptr. 889 , 410 P.2d 393 ( Miller ).) Every year, numerous children in the 10 jurisdictions are found to be suffering from lead poisoning due to their exposure to lead paint. "[T]he lead will not disappear on its own." So long as interior residential lead paint continues to exist in the 10 jurisdictions, this nuisance will continue to be an ongoing and imminent risk to the health of the children in the 10 jurisdictions. The trial court did not abuse its discretion *111 in determining that the danger posed by interior residential lead paint in the 10 jurisdictions poses a sufficiently serious and imminent risk of harm to merit abatement.
Defendants also contend that abatement is unwarranted because plaintiff failed to show that abatement will reduce the BLLs of children in the 10 jurisdictions. Plaintiff presented expert testimony that abatement is effective at reducing BLLs in children. Defendants concede that plaintiff presented such evidence, but they maintain that this expert opinion testimony was "inadmissible guesswork." 52 The trial court admitted this evidence, and defendants make no effort to demonstrate that the court abused its broad discretion in doing so. Their citation to Sargon Enterprises, Inc. v. University of Southern California (2012) 55 Cal.4th 747 , 149 Cal.Rptr.3d 614 , 288 P.3d 1237 ( Sargon ) is not helpful to their contention. Sargon held that the trial court has discretion as a "gatekeeper" to determine "whether the matter relied on [by an expert] can provide a reasonable basis for the opinion or whether that opinion is based on a leap of logic or conjecture." ( Sargon , at pp. 771-772, 149 Cal.Rptr.3d 614 , 288 P.3d 1237 .) Defendants fail to establish that the trial court abused its discretion in finding that plaintiff's expert's opinion regarding BLL reductions had a reasonable basis. Since the evidence was properly admitted, the trial court was entitled to credit it. The substance of defendants' argument is that the trial court should not have credited this testimony, but an appellate court must defer to a trial court's credibility determinations. We reject this contention.
B. Public Right
Defendants contend that plaintiff failed to establish that interior residential lead paint interferes with any "public right." 53
" ' Anything which is injurious to health ... or is indecent or offensive to the senses, or an obstruction to the free use of property, so as to interfere with the comfortable enjoyment of life or property *552 ... is a *112 nuisance.' ( Civ. Code, § 3479, italics added.) 'A public nuisance is one which affects at the same time an entire community or neighborhood, or any considerable number of persons, although the extent of the annoyance or damage inflicted upon individuals may be unequal.' ( Civ. Code, § 3480 [, italics added].) ... [¶] ' [P]ublic nuisances are offenses against, or interferences with, the exercise of rights common to the public. ' ( People ex rel. Gallo v. Acuna (1997) 14 Cal.4th 1090 , 1103 [ 60 Cal.Rptr.2d 277 , 929 P.2d 596 ], [first italics added, second italics are] original italics.) 'Of course, not every interference with collective social interests constitutes a public nuisance. To qualify,

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Source: Frix Law Library, https://www.frixlaw.com/law-library/cases/6106216. Public record. Not legal advice.