Causation in Asbestos Cases

Decisions in our library in which the court ruled on medical or specific causation: 1,200 cases, by state. Each line gives what the court held, in our words; the law differs from state to state and changes, so read the opinion and talk to a lawyer before relying on any of them.

About this issue

Every injury claim has to show causation. Courts often split it in two: general causation (can this kind of exposure cause this disease at all?) and specific causation (did it cause this person's disease?). For mesothelioma, asbestosis and lung cancer, general causation is rarely the main dispute. The fight is usually over whether a particular defendant's product contributed to the disease. How liability is then divided among responsible companies is a separate question; see apportionment.

Most states ask whether a defendant's product was a substantial factor in causing the disease. Because asbestos diseases are dose-related and most workers were exposed to many products, courts have had to decide what evidence ties one product, among many, to the disease:

• Cumulative-exposure testimony, that each meaningful exposure adds to the total dose that caused the disease, has been accepted by many courts when it is tied to evidence of real exposure to the defendant's product.
• A blanket opinion that every exposure above background, however small, is a substantial cause has been rejected by several courts as too general.
• Courts also weigh the product's asbestos content and fiber type, how it was used, how often the person was around it, and the timing of exposures against the disease's latency.

Cases on this issue often overlap with product identification and expert testimony.

Alabama

• Bobo v. Tennessee Valley Authority (2017). Predicting Alabama law, the court held that an employer has a duty to prevent take-home asbestos exposure of an employee's household members when the injury is foreseeable and public policy supports a duty. The court also held that medical charges written off by providers under insurer agreements are not recoverable as damages.
• Bobo v. Tennessee Valley Authority (2015). Applying Alabama law as it predicted, the court held that an employer owes a duty of reasonable care to an employee's household member exposed to asbestos carried home on work clothes, and that substantial factor causation applies to asbestos negligence claims involving multiple exposures. It also held that TVA was not shielded by the discretionary function doctrine because it violated mandatory rules.
• Bobo v. Tennessee Valley Authority (2015). The court concluded that Alabama law has no controlling answer on whether a premises owner owes a duty to workers' family members for take-home asbestos exposure, or on whether but-for or substantial-factor causation applies to multiple asbestos exposures, so it certified both questions to the state supreme court.
• Bobo v. Tennessee Valley Authority (2014). An expert's opinion that each significant asbestos exposure contributes to the total dose and is a substantial contributing factor in causing mesothelioma is not inherently unreliable when supported by scientific literature. Remaining objections go to the weight of the testimony, not its admissibility.

Alaska

• Peek v. Skw/clinton (1993). An employer may use the "last injurious exposure" rule as a defense where the employee settled with the last potentially liable employer who was properly before the Board. The Board's finding that the last employer's exposure was a substantial factor was supported by substantial evidence.

Arizona

• Coulbourn v. Crane Co. (2018). Under Arizona law, where several defendants' asbestos products may have caused an indivisible injury, a defendant's product is a causal factor if it was a substantial factor, meaning it was independently sufficient to cause the disease. Evidence that a manufacturer knew its gaskets would expose workers to fatal dust can support punitive damages.

Arkansas

• Thomas v. Borg-Warner Morse Tec LLC (2018). Under Arkansas law, a plaintiff must show frequent exposure to a defendant's asbestos product and causation, and market share liability is not allowed. A non-buyer warranty claimant must give the defendant pre-suit notice, and a design defect claim does not require proof of a safer alternative design.
• Chavers v. General Motors Corp. (2002). Arkansas adopts the 'frequency, regularity, and proximity' test for causation in asbestos cases. The plaintiff must show exposure to a particular defendant's asbestos-containing product, with sufficient frequency and regularity, near where the plaintiff worked, so that it is probable the exposure caused the injury.
• Alcoa v. Vann (2nd Division, 1985). Under the substantial-evidence standard, the Commission's finding of a causal connection between the occupational disease and employment by clear and convincing evidence stands if fair-minded persons could have reached it; the Commission weighs conflicting medical opinions, and medical certainty is not required.

California

• Brooks v. Mission Stucco Company (2nd Appellate District, 3rd Division, 2024). A special verdict that finds a single design defect both was and was not a substantial factor in causing harm is irreconcilably inconsistent, and the reviewing court cannot choose between the answers. A new trial may be limited to liability on that theory and fault allocation, leaving the total damages intact.
• Marcus v. Air & Liquid Systems Corporation (2024). Under maritime law, plaintiffs can reach a jury on substantial-factor causation with testimony about the work done on a product, evidence the product contained asbestos, and expert estimates of exposure from that work, without relying on an "every exposure" theory. The government contractor defense does not apply to federal maritime claims, and loss of consortium and punitive damages are unavailable under maritime law.
• Sarjeant v. Foster Wheeler LLC (2024). A later declaration naming specific products does not count as a sham affidavit unless it clearly and unambiguously contradicts earlier testimony. Disputed evidence about whether a defendant's talc went into the products the plaintiff used is for the jury.
• Smargisso v. Air & Liquid Systems Corporation (2024). Under maritime law, plaintiffs must show actual exposure to the defendant's asbestos products and that the exposure was a substantial contributing factor; circumstantial shipmate and records evidence can meet this. Non-pecuniary damages are not recoverable in a maritime wrongful death action based on negligence and strict liability absent historical support.
• Speck v. CBS Corporation (2024). Under federal maritime law a plaintiff must show actual exposure to the defendant's asbestos-containing product and that the exposure was a substantial contributing factor in causing the injury, and expert testimony is not required to prove this. The government contractor defense fails where the product was substantially the same as one sold commercially or the contractor did not show the Navy required asbestos.
• Elorreaga v. Rockwell Automation, Inc. (2023). The Boyle government contractor defense rests on preemption of state law, so it does not apply to claims brought under federal maritime law. Plaintiffs' evidence of exposure to each defendant's products and of a substantial contributing factor was enough to create a genuine factual dispute.
• Elorreaga v. Rockwell Automation, Inc. (2023). Under federal maritime law, plaintiffs must show exposure to a defendant's product was a substantial factor in causing the illness. Expert testimony that considers the nature, frequency and proximity of exposure, even qualitatively, is not an excluded 'every exposure' theory.
• Ochoa v. Spx Cooling Technologies, Inc. (1st Appellate District, 1st Division, 2023). In an asbestos injury case, a plaintiff must show threshold exposure to the defendant's asbestos-containing products; evidence that the worker may have worked on some tower that might have had asbestos parts, without evidence that his work disturbed asbestos, is speculation and does not create a triable issue.
• Bader v. Johnson & Johnson (1st Appellate District, 4th Division, 2022). A trial court's gatekeeping of expert opinion under Sargon is reviewed for abuse of discretion, and Rutherford's 'substantial factor contributing to the risk' causation standard may be applied to a fibrous talc theory where the same causation uncertainties exist as in asbestos cancer cases. Instructional and evidentiary errors that are assumed but not shown to have affected the verdict do not require reversal.
• Shelton v. Air & Liquid Systems Corporation (2022). Under federal maritime law, a specific-causation expert must analyze the plaintiff's actual exposure (frequency, duration, proximity) to each defendant's products, by a qualitative or quantitative method, rather than relying on product presence and general causation principles.
• Ann Strobel v. Johnson & Johnson (1st Appellate District, 4th Division, 2021). An expert may not relay an absent expert's case-specific test results as hearsay, but may rely on generally reliable third-party sources. Long-term product use, asbestos in the source talc ore, and reasonable inferences from the expert evidence were enough to create a triable issue on exposure to asbestos in the product.
• Harris v. Thomas Dee Engineering Co., Inc. (1st Appellate District, 5th Division, 2021). A court may not give no weight to an expert's declaration opposing summary judgment just because it was not disclosed in the expert's deposition or conflicts with it. The D'Amico rule on contradictory discovery admissions guides whether a triable issue exists but does not make such a declaration inadmissible, and it does not apply where the declaration reasonably explains the difference.
• Toy v. Warren Pumps (In re Asbestos) (2021). Maritime law applies to naval shipyard asbestos claims where some exposure occurred aboard vessels in drydock, and plaintiffs must show exposure to the defendant's asbestos products that was a substantial factor in causing the disease. A pump maker may owe a duty to warn about asbestos in third-party parts its product requires, and conflicting evidence on exposure precludes summary judgment.
• Toy v. Armstrong Int'l (In re Asbestos) (2021). An expert need not be formally credentialed in a specific field to be qualified under Rule 702, and criticism of animal-based research goes to weight, not admissibility. The court denied the motion to exclude "every exposure" testimony because plaintiffs' experts did not appear to rely on that theory, but said it would exclude such testimony if offered at trial.
• Toy v. Honeywell Int'l (In re Asbestos) (2021). Under Rule 702 and Daubert, a causation expert's qualitative assessment of asbestos exposure, which considers the type, amount and duration of the work and the fiber levels it produces, can be admitted without a quantified dose. Disputes over the factual assumptions and competing studies go to weight and cross-examination.
• Toy v. Armstrong Int'l (In re Asbestos) (2021). A rebuttal expert report must respond to new, unforeseen matters; opinions on issues where the offering party bears the burden of proof belong in the opening expert disclosures, so the rest of the report may be struck even though both sides missed the scheduling deadlines.
• Putt v. Ford Motor Co. (In re Laosd Asbestos Cases) (2nd Appellate District, 2nd Division, 2021). Where the jury found Ford's brake pads defective and a substantial factor in causing mesothelioma, and it was undisputed that other makers' brake pads were identical and also exposed the plaintiff, the evidence compelled apportioning some nonzero fault to those others, and a defendant need not prove precise percentages to overturn a 100 percent apportionment.
• Toy v. Armstrong Int'l (In re Toy Asbestos) (2021). Under California law, a product maker is not liable for asbestos in third-party gaskets or insulation used with its product unless its own product contributed substantially to the harm or it mandated or advised use of the asbestos parts. Foreseeability that such parts would be used is not enough.
• Leavitt v. Johnson & Johnson (1st Appellate District, 5th Division, 2021). A plaintiff alleging mesothelioma from asbestos-contaminated talc must show it is more likely than not the product was contaminated when used, and that exposure was a substantial factor in contributing to the risk of disease; no dose-level estimate or testing of the plaintiff's own container is required. An appellant must show both error and prejudice.
• Sabetian v. Fluor Enterprises, Inc. (2nd Appellate District, 7th Division, 2021). A jury's asbestos causation finding stands if substantial evidence shows exposure to the defendant's product substantially contributed to the plaintiff's aggregate dose. An expert may rely on case reports for a very rare disease, and a request to apply foreign law must be timely. Under California's governmental interest test, California law governed compensatory damages.
• Spurlin v. Air & Liquid Systems Corporation (2021). Under federal maritime law, a manufacturer has a duty to warn when its product requires incorporation of a part, it knows or has reason to know the integrated product is likely dangerous, and it has no reason to believe users will realize the danger. Punitive damages and loss of consortium are not available in a maritime negligence action.
• Swanson v. The Marley-Wylain Co. (2nd Appellate District, 1st Division, 2021). Michigan law governed the negligence claim, and under it a plaintiff must show that the defendant's conduct was a substantial factor in producing the injury, not merely in increasing the risk of injury. An instruction using California's risk-contribution standard was therefore error.
• Vanni v. Honeywell International, Inc. (2nd Appellate District, 8th Division, 2021). In an asbestos case, causation requires proof of exposure and that the exposure was a substantial factor in contributing to the risk of disease. Expert opinion that is speculative is not substantial evidence, but under substantial-evidence review the jury resolves conflicts between experts and the evidence is viewed in the prevailing party's favor.
• Viale v. Foster Wheeler, LLC (2021). Plaintiffs must present non-speculative evidence that the defendant's asbestos-containing product or conduct was a substantial factor in causing the disease; a hirer of an independent contractor is presumptively not liable absent affirmative contribution to the injury, such as supplying unsafe equipment or exercising retained control.
• Webb v. General Cable Corp. (1st Appellate District, 1st Division, 2021). A plaintiff must prove threshold exposure to the defendant's asbestos-containing product, and evidence showing only a possibility or speculation of such exposure is not substantial evidence. Without it there is no causation and no liability.
• Barr v. Parker-Hannifin Corp. (1st Appellate District, 3rd Division, 2020). Expert and lay testimony that a plaintiff's father may have brought shipyard asbestos home was properly excluded because it rested on speculation about actual exposure. Punitive damages were supported by substantial evidence that the manufacturer knew of asbestos hazards, warned its own employees, and did not warn its customers.
• Booker v. Imerys Talc America, Inc. (1st Appellate District, 3rd Division, 2020). A jury may find a worker was exposed to asbestos-contaminated talc from the manufacturer's own laboratory reports, internal documents and coworker testimony, without expert analysis of the manufacturer's samples. A party seeking to allocate fault to nonparties on a verdict form must point to evidence of their wrongdoing. A buyer that broadly assumes all liabilities relating to a business's assets takes on liability for the seller's earlier product sales.
• Kramer v. Amcord Inc. (1st Appellate District, 3rd Division, 2020). A trial court does not abuse its discretion under Evidence Code section 721(b)(3) where an expert's acknowledgment that a publication is generally reliable does not establish it as a reliable authority on the causation issue, and an economic damages award stands if supported by substantial evidence.
• Gibbons v. Johnson & Johnson Consumer (Laosd Asbestos Cases) (2nd District, Division 4, 2020). When a talc manufacturer supports summary judgment with expert testimony that its talc is asbestos-free, the plaintiff must produce competent evidence, in practice expert testimony, that the products she used were more likely than not contaminated with asbestos. Documents and an attorney's characterizations do not suffice.
• Berg v. Colgate-Palmolive Company (1st Appellate District, 1st Division, 2019). A plaintiff opposing summary judgment must present evidence from which a jury could find it more likely than not that the specific product used contained asbestos; evidence showing only a possibility of exposure is insufficient.
• Deere v. Lizarraga (2019). A prison official is liable under the Eighth Amendment for unsafe conditions only if he knows inmates face a substantial risk of serious harm and disregards it. A warden's knowledge is not presumed from his position, and the plaintiff must offer evidence of exposure and causation.
• Friedman v. American Biltrite (In re Laosd Asbestos Cases) (2nd Appellate District, 4th Division, 2019). Asbestos exposure may be shown through a plaintiff's testimony about breathing dust from an asbestos-containing product, and expert testimony that any exposure above background can increase mesothelioma risk can support substantial factor causation without a dose estimate. A minor difference between a study's method and the case facts goes to weight, not admissibility.
• Lopez v. the Hillshire Brands Company (1st Appellate District, 5th Division, 2019). CACI No. 435, the asbestos substantial-factor instruction based on Rutherford, applies to an asbestos claim against a premises owner that is not a manufacturer or supplier, and a 'but-for' causation instruction is not required where there may be multiple sources of exposure.
• Schildknegt v. Air and Liquid Systems Corp. (2nd Appellate District, 4th Division, 2019). A defendant does not shift the summary judgment burden on asbestos exposure unless it negates every pleaded theory, including that it acted as a supplier of replacement parts. A brand name on packaging is nonhearsay circumstantial evidence of a product's source. Under Rutherford, a plaintiff needs threshold exposure plus expert testimony that the exposure contributed to the risk of disease, and need not show a particular length, intensity or frequency of exposure.
• Foglia v. Moore Dry Dock Company (1st Appellate District, 2nd Division, 2018). A defendant can shift the burden on summary judgment through plaintiffs' factually devoid discovery responses and other evidence, and an expert opinion resting on assumed facts with no admissible evidentiary support (here, that the father worked around asbestos at the shipyard) lacks foundation and cannot raise a triable issue.
• Hake v. Allied Fluid Products Corp. (1st Appellate District, 4th Division, 2018). A party who does not timely ask the trial court to apply a particular state's law waives that choice-of-law argument on appeal. Under the Kansas statute, a plaintiff must show the exposure was a substantial factor in causing the injury, and expert testimony that the exposure only contributed to the risk or was one of many cumulative exposures did not meet that standard.
• Hilt v. Foster Wheeler LLC (2018). Under maritime law, a plaintiff must show exposure to asbestos material the defendant manufactured or supplied and that the exposure was a substantial contributing factor in causing the injury. Here, deposition testimony and an expert declaration created genuine factual disputes on exposure to Foster Wheeler boilers and on the bare metal defense.
• Trapp v. CertainTEED Corporation (6th Appellate District, 2018). A defendant moving for summary judgment must produce admissible evidence negating an element of the claim, and an expert opinion built on case-specific data that is not in the record has no evidentiary value. Strict products liability can reach defendants in the stream of commerce when bystander injury is reasonably foreseeable.
• Wittman v. Coty, Inc. (2nd Appellate District, 4th Division, 2018). A defendant meets its initial summary judgment burden when the plaintiff's comprehensive discovery responses are factually devoid on product exposure to asbestos, and expert test results on a product sample may be excluded where the chain of custody linking the tested sample to the plaintiff's product is not established.
• DeLOOF v. Ace Hardware Corp. (2nd Appellate District, 4th Division, 2017). A defendant can meet its summary judgment burden by showing through factually devoid discovery responses that the plaintiff cannot prove exposure to its asbestos-containing product, and by expert testimony that no respirable fibers were released. The plaintiff must then produce evidence of a triable issue, and causation cannot rest on speculation.
• Duty v. Trz Realty, LLC (1st Appellate District, 3rd Division, 2017). A physician with long experience reviewing epidemiological studies need not be an epidemiologist or gastroenterologist to be qualified to opine on asbestos causation of colon cancer, and a trial court acting as gatekeeper may not resolve scientific disputes over the studies or weigh competing opinions.