CACI No. 435. Causation for Asbestos-Related Cancer Claims

Judicial Council of California Civil Jury Instructions (2024 edition)

Download PDF
435.Causation for Asbestos-Related Cancer Claims
A substantial factor in causing harm is a factor that a reasonable person
would consider to have contributed to the harm. It does not have to be
the only cause of the harm.
[Name of plaintiff] may prove that exposure to asbestos from [name of
defendant]’s [product/ [,/or] activities/ [,/or] property/ [,/or] operations]
was a substantial factor causing [his/her/nonbinary pronoun/[name of
decedent]’s] illness by showing, through expert testimony, that there is a
reasonable medical probability that the exposure was a substantial factor
contributing to [his/her/nonbinary pronoun] risk of developing cancer.
New September 2003; Revised December 2007, May 2018, November 2018, May
2020, November 2020
Directions for Use
This instruction is to be given in a case in which the plaintiff’s claim is that the
plaintiff contracted an asbestos-related disease from exposure to the defendant’s
asbestos-containing product or asbestos-related activities. (See Rutherford v. Owens-
Illinois, Inc. (1997) 16 Cal.4th 953, 982-983 [67 Cal.Rptr.2d 16, 941 P.2d 1203];
Lopez v. The Hillshire Brands Co. (2019) 41 Cal.App.5th 679, 688 [254 Cal.Rptr.3d
377] [addressing causation standard for exposure to asbestos from a defendant’s
property or operation when the defendant is not a manufacturer or supplier of
asbestos-containing products]; but see Petitpas v. Ford Motor Co. (2017) 13
Cal.App.5th 261, 290 [220 Cal.Rptr.3d 185] [court gave CACI No. 435 with regard
to premises liability defendant].) If the plaintiff’s claim is based on anything other
than disease resulting from asbestos exposure, then this instruction is not to be
If the issue of medical causation is tried separately, revise this instruction to focus
on that issue.
If necessary, CACI No. 431, Causation: Multiple Causes, may also be given.
Sources and Authority
“In the context of a cause of action for asbestos-related latent injuries, the
plaintiff must first establish some threshold exposure to the defendant’s defective
asbestos-containing products, and must further establish in reasonable medical
probability that a particular exposure or series of exposures was a ‘legal cause’
of his injury, i.e., a substantial factor in bringing about the injury. In an
asbestos-related cancer case, the plaintiff need not prove that fibers from the
defendant’s product were the ones, or among the ones, that actually began the
process of malignant cellular growth. Instead, the plaintiff may meet the burden
of proving that exposure to defendant’s product was a substantial factor causing
the illness by showing that in reasonable medical probability it was a substantial
factor contributing to the plaintiff’s or decedent’s risk of developing cancer. The
jury should be so instructed. The standard instructions on substantial factor and
concurrent causation remain correct in this context and should also be given.”
(Rutherford, supra, 16 Cal.4th at pp. 982-983, original italics, internal citation
and footnotes omitted.)
“Squarely faced with the issue of CACI No. 435’s correctness for a non-
manufacturer/non-supplier, we conclude that CACI No. 435 applied to plaintiffs’
asbestos-related claim, even though [defendant] is not a manufacturer or supplier
of asbestos. [¶] CACI No. 435 was developed to address the special
considerations that apply when the injury was allegedly caused by asbestos
exposure. These include the long latency period, the occupational settings that
often expose workers to multiple forms and brands of asbestos, and, in a case of
exposure to asbestos from multiple sources, the difficulty of proving that a
plaintiff’s or decedent’s illness was caused by particular asbestos fibers traceable
to the defendant. These considerations are similar whether the defendant was a
manufacturer/supplier or otherwise created the exposure to asbestos.” (Lopez,
supra, 41 Cal.App.5th at p. 687, internal citation omitted.)
“The term ‘substantial factor has not been judicially defined with specificity, and
indeed it has been observed that it is ‘neither possible nor desirable to reduce it
to any lower terms.’ This court has suggested that a force which plays only an
‘infinitesimal’ or ‘theoretical’ part in bringing about injury, damage, or loss is not
a substantial factor. Undue emphasis should not be placed on the term
‘substantial.’ For example, the substantial factor standard, formulated to aid
plaintiffs as a broader rule of causality than the ‘but for test, has been invoked
by defendants whose conduct is clearly a ‘but for cause of plaintiff’s injury but
is nevertheless urged as an insubstantial contribution to the injury. Misused in
this way, the substantial factor test ‘undermines the principles of comparative
negligence, under which a party is responsible for his or her share of negligence
and the harm caused thereby.’ (Rutherford, supra, 16 Cal.4th at p. 969, internal
citations omitted.)
“[A] very minor force that does cause harm is a substantial factor. This rule
honors the principle of comparative fault.” (Bockrath v. Aldrich Chem. Co.
(1999) 21 Cal.4th 71, 79 [86 Cal.Rptr.2d 846, 980 P.2d 398], internal citation
“Contrary to defendant’s assertion, the California Supreme Court’s decision in
Viner v. Sweet (2003) 30 Cal.4th 1232 [135 Cal.Rptr.2d 629, 70 P.3d 1046]
(Viner) did not alter the causation requirement in asbestos-related cases. In Viner,
the court noted that subsection (1) of section 432 of the Restatement Second of
Torts, which provides that ‘the actors negligent conduct is not a substantial
factor in bringing about harm to another if the harm would have been sustained
even if the actor had not been negligent,’ ‘demonstrates how the “substantial
factor” test subsumes the traditional “but for” test of causation.’ Defendant
argues that Viner required plaintiffs to show that defendant’s product
‘independently caused [plaintiff’s] injury or that, but for that exposure, [plaintiff]
would not have contracted lung cancer.’ Viner, however, is a legal malpractice
case. It does not address the explicit holding in Rutherford that ‘plaintiffs may
prove causation in asbestos-related cancer cases by demonstrating that the
plaintiff’s exposure to defendant’s asbestos-containing product in reasonable
medical probability was a substantial factor in contributing to the aggregate dose
of asbestos the plaintiff or decedent inhaled or ingested, and hence to the risk of
developing asbestos-related cancer, without the need to demonstrate that fibers
from the defendant’s particular product were the ones, or among the ones, that
actually produced the malignant growth.’ Viner is consistent with Rutherford
insofar as Rutherford requires proof that an individual asbestos-containing
product is a substantial factor contributing to the plaintiff’s risk or probability of
developing cancer.” (Jones v. John Crane, Inc. (2005) 132 Cal.App.4th 990, 998,
fn. 3 [35 Cal.Rptr.3d 144], internal citations omitted.)
‘A threshold issue in asbestos litigation is exposure to the defendant’s
product. . . . If there has been no exposure, there is no causation.’ Plaintiffs bear
the burden of ‘demonstrating that exposure to [defendant’s] asbestos products
was, in reasonable medical probability, a substantial factor in causing or
contributing to [plaintiff’s] risk of developing cancer.’ ‘Factors relevant to
assessing whether such a medical probability exists include frequency of
exposure, regularity of exposure and proximity of the asbestos product to
[plaintiff].’ Therefore, ‘[plaintiffs] cannot prevail against [defendant] without
evidence that [plaintiff] was exposed to asbestos-containing materials
manufactured or furnished by [defendant] with enough frequency and regularity
as to show a reasonable medical probability that this exposure was a factor in
causing the plaintiff’s injuries.’ (Whitmire v. Ingersoll-Rand Co. (2010) 184
Cal.App.4th 1078, 1084 [109 Cal.Rptr.3d 371], internal citations omitted.)
“[G]iving CACI No. 430, which states that a factor is not substantial when it is
‘remote or trivial,’ could be misleading in an asbestos case, where the long
latency period necessitates exposures will have been several years earlier. Jury
instructions therefore should not suggest that a long latency period, in which the
exposure was temporally ‘remote,’ precludes an otherwise sufficient asbestos
claim. “Remote” often connotes a time limitation. Nothing in Rutherford
suggests such a limitation; indeed, asbestos cases are brought long after exposure
due to the long-term latent nature of asbestos-related diseases.’ It was not error
for the court to give CACI No. 435 alone instead of CACI No. 430.” (Lopez,
supra, 41 Cal.App.5th at p. 688, internal citation omitted.)
“That the Use Notes caution against giving the more general CACI No. 430 in a
mesothelioma case, when the more specific instruction CACI No. 435 is more
applicable, does not support a conclusion that it was error to give both
instructions. CACI No. 430 is a correct statement of the law relating to
substantial factor causation, even though, as Rutherford noted, more specific
instructions also must be given in a mesothelioma case. Because the more
specific CACI No. 435 also was given, we do not find that the trial court erred
by giving both instructions.” (Petitpas, supra, 13 Cal.App.5th at p. 299, original
“Further, ‘[t]he mere “possibility” of exposure’ is insufficient to establish
causation. ‘[P]roof that raises mere speculation, suspicion, surmise, guess or
conjecture is not enough to sustain [the plaintiff’s] burden’ of persuasion.” (Izell
v. Union Carbide Corp. (2014) 231 Cal.App.4th 962, 969 [180 Cal.Rptr.3d 382],
internal citations omitted.)
“[T]here is no requirement that plaintiffs show that [defendant] was the
exclusive, or even the primary, supplier of asbestos-containing gaskets to
PG&E.” (Turley v. Familian Corp. (2017) 18 Cal.App.5th 969, 981 [227
Cal.Rptr.3d 321].)
“[T]o establish exposure in an asbestos case a plaintiff has no obligation to
prove a specific exposure to a specific product on a specific date or time. Rather,
it is sufficient to establish ‘that defendant’s product was definitely at his work
site and that it was sufficiently prevalent to warrant an inference that plaintiff
was exposed to it’ during his work there.” (Turley,supra, 18 Cal.App.5th at p.
“To support an allocation of liability to another party in an asbestos case, a
defendant must ‘present evidence that the aggregate dose of asbestos particles
arising from’ exposure to that party’s asbestos ‘constituted a substantial factor in
the causation of [the decedent’s] cancer.’ (Soto v. BorgWarner Morse TEC Inc.
(2015) 239 Cal.App.4th 165, 205 [191 Cal.Rptr.3d 263].)
‘[G]iven the long latency period of asbestos-related disease, and the
occupational settings that commonly exposed the worker to multiple forms and
brands of asbestos products with varying degrees of toxicity,’ our Supreme Court
has held that a plaintiff ‘need not prove with medical exactitude that fibers from
a particular defendant’s asbestos-containing products were those, or among those,
that actually began the cellular process of malignancy.’ Rather, a ‘plaintiff may
meet the burden of proving that exposure to defendant’s product was a
substantial factor causing the illness by showing that in reasonable medical
probability it was a substantial factor contributing to the plaintiff’s or decedent’s
risk of developing cancer.’ (Izell, supra, 231 Cal.App.4th at p. 975, original
italics, internal citation omitted.)
“Many factors are relevant in assessing the medical probability that an exposure
contributed to plaintiff’s asbestos disease. Frequency of exposure, regularity of
exposure, and proximity of the asbestos product to plaintiff are certainly
relevant, although these considerations should not be determinative in every
case. [Citation.] Additional factors may also be significant in individual cases,
such as the type of asbestos product to which plaintiff was exposed, the type of
injury suffered by plaintiff, and other possible sources of plaintiff’s injury.
[Citations.] ‘Ultimately, the sufficiency of the evidence of causation will depend
on the unique circumstances of each case.’ [Citation.] (Paulus v. Crane Co.
(2014) 224 Cal.App.4th 1357, 1363-1364 [169 Cal.Rptr.3d 373].)
“In this case, [defendant] argues the trial court’s refusal to give its proposed
instruction was error because the instruction set forth ‘the requirement in
Rutherford that causation be decided by taking into account “the length,
frequency, proximity and intensity of exposure, the peculiar properties of the
individual product, [and] any other potential causes to which the disease could
be attributed.” But Rutherford does not require the jury to take these factors
into account when deciding whether a plaintiff’s exposure to an asbestos-
containing product was a substantial factor in causing mesothelioma. Instead,
those factors are ones that a medical expert may rely upon in forming his or her
expert medical opinion.” (Davis v. Honeywell Internat. Inc. (2016) 245
Cal.App.4th 477, 495 [199 Cal.Rptr.3d 583], internal citation omitted.)
“Mere presence at a site where asbestos was present is insufficient to establish
legally significant asbestos exposure.” (Shiffer v. CBS Corp. (2015) 240
Cal.App.4th 246, 252 [192 Cal.Rptr.3d 346].)
“We disagree with the trial court’s view that Rutherford mandates that a medical
doctor must expressly link together the evidence of substantial factor causation.
The Rutherford court did not create a requirement that specific words must be
recited by appellant’s expert. Nor did the Rutherford court specify that the
testifying expert in asbestos cases must always be ‘somebody with an M.D. after
his name.’ The Rutherford court agreed with the Lineaweaver court that ‘the
reference to “medical probability” in the standard “is no more than a recognition
that asbestos injury cases (like medical malpractice cases) involve the use of
medical evidence.” [Citation.]’ The Supreme Court has since clarified that
medical evidence does not necessarily have to be provided by a medical doctor.”
(Hernandez v. Amcord, Inc. (2013) 215 Cal.App.4th 659, 675 [156 Cal.Rptr.3d
90], internal citations omitted.)
“Nothing in Rutherford precludes a plaintiff from establishing legal causation
through opinion testimony by a competent medical expert to the effect that every
exposure to respirable asbestos contributes to the risk of developing
mesothelioma. On the contrary, Rutherford acknowledges the scientific debate
between the ‘every exposure’ and ‘insignificant exposure’ camps, and recognizes
that the conflict is one for the jury to resolve.” (Izell, supra, 231 Cal.App.4th at
p. 977.)
“[T]he identified-exposure theory is a more rigorous standard of causation than
the every-exposure theory. As a single example of the difference, we note
[expert]’s statement that it ‘takes significant exposures’ to increase the risk of
disease. This statement uses the plural ‘exposures’ and also requires that those
exposures be ‘significant.’ The use of ‘significant’ as a limiting modifier appears
to be connected to [expert]’s earlier testimony about the concentrations of
airborne asbestos created by particular activities done by [plaintiff], such as
filing, sanding and using an airhose to clean a brake drum.” (Phillips v.
Honeywell Internat. Inc. (2017) 9 Cal.App.5th 1061, 1088 [217 Cal.Rptr.3d
“Nor is there a requirement that ‘specific words must be recited by [plaintiffs’]
expert.’ [¶] The connection, however, must be made between the defendant’s
asbestos products and the risk of developing mesothelioma suffered by the
decedent.” (Paulus, supra, 224 Cal.App.4th at p. 1364.)
“We hold that the duty of employers and premises owners to exercise ordinary
care in their use of asbestos includes preventing exposure to asbestos carried by
the bodies and clothing of on-site workers. Where it is reasonably foreseeable
that workers, their clothing, or personal effects will act as vectors carrying
asbestos from the premises to household members, employers have a duty to
take reasonable care to prevent this means of transmission. This duty also
applies to premises owners who use asbestos on their property, subject to any
exceptions and affirmative defenses generally applicable to premises owners,
such as the rules of contractor liability. Importantly, we hold that this duty
extends only to members of a workers household. Because the duty is premised
on the foreseeability of both the regularity and intensity of contact that occurs in
a workers home, it does not extend beyond this circumscribed category of
potential plaintiffs.” (Kesner v. Superior Court (2016) 1 Cal.5th 1132, 1140 [210
Cal.Rptr.3d 283, 384 P.3d 283].)
Secondary Sources
3 Witkin, California Procedure (5th ed. 2008) Actions, § 570
Haning et al., California Practice Guide: Personal Injury, Ch. 2(II)-D, Theories of
Recovery - Strict Liability For Defective Products, 2:1259 (The Rutter Group)
Haning et al., California Practice Guide: Personal Injury, Ch. 2(II)-O, Theories of
Recovery - Causation Issues, 2:2409 (The Rutter Group)
1 Levy et al., California Torts, Ch. 2, Causation, § 2.03 (Matthew Bender)
California Products Liability Actions, Ch. 2, Liability for Defective Products, § 2.22,
Ch. 7, Proof, § 7.06 (Matthew Bender)
33 California Forms of Pleading and Practice, Ch. 380, Negligence, § 380.72
(Matthew Bender)
436-439. Reserved for Future Use

© Judicial Council of California.