Hawaiʻi Adopts Restatement (Third) Toxic-Tort Causation Framework: Exposure, General Causation, and Specific Causation

I. Introduction

Patrickson v. DOW Chemical Company and Del Monte Fresh Produce N.A., Inc. (Haw. Sept. 21, 2026) is a major Hawaiʻi Supreme Court decision in a decades-long DBCP toxic-tort action brought by Central and South American banana plantation workers. The plaintiffs alleged reproductive injuries caused by exposure to the pesticide dibromochloropropane (“DBCP”) used on banana farms operated by a Del Monte subsidiary (Bandeco) and manufactured by Dow.

The certiorari dispute centered on one plaintiff, Fernando Jimenez Arias (“Arias”), who worked as a quality fruit inspector. The circuit court had (1) granted summary judgment against Arias on causation/exposure grounds and (2) excluded the plaintiffs’ toxicology expert, Michael J. DiBartolomeis, Jr., on the view that his opinions lacked a factual foundation because there was “simply no evidence” Arias was exposed.

The Intermediate Court of Appeals (ICA) vacated those rulings. The supreme court affirmed the ICA and, critically, used the case to announce a statewide toxic-tort causation framework.

II. Summary of the Opinion

  • New rule (core holding): Hawaiʻi adopts the causation approach in comment g to section 26 of the Restatement (Third) of Torts, organized as (1) exposure to the agent, (2) general causation, and (3) specific causation, with the court expressly reordering the Restatement’s discussion to place exposure first.
  • Rejection of proposed asbestos-style test: The court declines to adopt the asbestos “frequency, regularity, and proximity” test urged by defendants, noting (citing Fowler v. Akzo Nobel Chemicals, Inc.) it is merely a substantial-factor articulation.
  • Expert testimony requirement: Expert testimony is generally required to prove causation in toxic-tort cases.
  • No rigid dose requirement: The court refuses to impose a categorical “dosage quantification” requirement at summary judgment; plaintiffs should provide evidence of exposure including estimated amount/duration where possible, but the court “decline[s] to adopt any rigid test.”
  • Expert admissibility: Excluding DiBartolomeis was an abuse of discretion; his opinions had a sufficient factual basis under State v. Kim.
  • Summary judgment: Construing inferences in plaintiffs’ favor, Arias presented genuine disputes of material fact on exposure and specific causation; summary judgment was improper.

III. Analysis

A. Precedents Cited

1. Hawaiʻi’s prior causation law and the “mass tort” problem

The court roots its doctrinal shift in Smith v. Cutter Biological, Inc., a Div. of Miles Inc., which recognized that “traditional rules of negligence” can be “unworkable in mass tort cases” and warned that absent new approaches “otherwise innocent plaintiffs would be left without a remedy.” In Smith, identification of the actual manufacturer was impossible, so the court adopted “the alternative market share theory of recovery” (drawing from Restatement (Second) of Torts § 433B(3)).

By contrast, identity was not disputed here—Dow manufactured the DBCP used by Del Monte’s subsidiary—so market-share recovery was “inapposite.” Still, Smith provided the key policy premise: mass toxic-tort causation requires doctrinal adaptation.

2. The “substantial factor” lineage and why it is not enough here

Defendants’ preferred framing effectively returned the case to “substantial factor” causation. Hawaiʻi adopted that formulation in Mitchell v. Branch (via Restatement (First) of Torts § 431), and reaffirmed it as workable in Knodle v. Waikiki Gateway Hotel, Inc.. The court explains, however, that Smith had already recognized substantial-factor limits in mass toxic-tort settings.

Defendants urged the asbestos “frequency, regularity, and proximity” test, pointing to Fowler v. Akzo Nobel Chemicals, Inc.. The court used Fowler itself—along with federal asbestos authorities (Menne v. Celotex Corp.; Lohrmann v. Pittsburgh Corning Corp.)—to show that frequency/regularity/proximity is simply another way of asking whether the exposure was a substantial factor. The court therefore treated the proposal as a relabeling, not a solution to the “unworkable” feature identified in Smith.

3. Federal predictive authority and the general/specific causation structure

The decision engages Feindt v. United States (D. Haw. 2025), which predicted Hawaiʻi would (a) require expert testimony for toxic-tort causation and (b) analyze causation via the general/specific distinction applied in In re Hanford Nuclear Rsrv. Litig. The Hawaiʻi Supreme Court agrees with the expert-testimony prediction and adopts a more complete Restatement (Third) framework that explicitly includes exposure as a third organizing inquiry.

4. Expert testimony gatekeeping and admissibility

For admissibility, the court applied Hawaiʻi’s expert-testimony standard from State v. Kim, as reaffirmed in State v. Montalbo, emphasizing a “sound factual foundation” and “reliable system of analysis.” The opinion also reinforces the trial court’s “gatekeeping” role via State v. Vliet (relevance and reliability).

5. Summary judgment standards and burdens

The court restated de novo review for summary judgment from Fujimoto v. Au and clarified burdens using French v. Hawaii Pizza Hut, Inc. and Ralston v. Yim. These standards mattered because exposure and causation were largely circumstantial: if reasonable inferences could support plaintiffs, summary judgment had to be denied.

6. Proof of causation language and “no magic words”

Extending an older medical-causation principle, the court relied on Dzurik v. Tamura to hold that no “particular form of words” is required from experts in toxic-tort cases; terms like “might” or “probably” are circumstances for the factfinder to weigh.

7. Epidemiology and “doubling of risk” debates (declined as rigid rule)

The opinion surveys jurisdictions that require or discuss a “doubling” of relative risk (e.g., Bostic v. Georgia-Pac. Corp.; Allison v. McGhan Med. Corp.) and those rejecting rigid thresholds (e.g., In re Joint E. & S. Dist. Asbestos Litig.; Miller v. Pfizer, Inc.). It also notes additional approaches (e.g., Norris v. Baxter Healthcare Corp.; Rider v. Sandoz Pharms. Corp.) and references a practical exposure-evidence formulation from Lowery v. Enbridge Energy Ltd. P'ship (concurrence). Hawaiʻi ultimately refuses a hard threshold, favoring flexible, case-specific proof constrained by reliability gatekeeping.

8. Other Hawaiʻi Restatement adoption practice

The court situates its Restatement (Third) move within Hawaiʻi’s broader practice of using ALI Restatements as persuasive authority (citing Bynum v. Mango) and points to its recent adoption of a punitive-damages standard in Guieb v. Guieb.

B. Legal Reasoning

1. The new toxic-tort causation organization: exposure → general causation → specific causation

The court adopts Restatement (Third) of Torts: Phys. & Emot. Harm § 26, cmt. g, and ties its operational definitions to § 28, cmts. c(2)-(4):

  • Exposure to the agent: whether the plaintiff was exposed (inhalation, absorption/dermal, ingestion, etc.).
  • General causation: whether the agent is capable of causing the disease/condition.
  • Specific causation: whether the agent caused this plaintiff’s disease/condition.

The court explicitly reorders the inquiries because exposure is logically antecedent: “If there was no exposure, it is not necessary to address general or specific causation.”

2. Burden of proof remains but-for causation; structure is analytical, not a relaxation

While acknowledging the Restatement’s note that the categories are not always separate “elements,” the court clarifies that plaintiffs still must establish but-for causation by a preponderance of the evidence. The framework is an organizing tool designed to reflect the realities of scientific proof, not a substitution for the plaintiff’s ultimate burden.

3. Expert testimony is generally required; dosage quantification is not categorically required

Accepting the logic discussed in Feindt v. United States and Hawaiʻi’s medical-negligence rationale (citing Exotics Hawaii-Kona, Inc. v. E.I. Du Pont De Nemours & Co. and Craft v. Peebles and also Est. of Frey v. Mastroianni), the court holds expert testimony should be required in toxic-tort causation disputes because jurors cannot evaluate complex scientific causation without assistance.

But the court refuses to impose a strict “dose” or “dosage” quantification requirement, recognizing that in many real-world contamination scenarios precise dose cannot be reliably calculated. Instead, plaintiffs should provide some exposure evidence, “including the estimated amount and duration of exposure,” sufficient to permit reasonable (not speculative) inferences, while trial courts police reliability through gatekeeping.

4. Application to the record: why summary judgment could not stand

On exposure, the court relied on circumstantial evidence viewed in the nonmovant’s favor:

  • Arias rotated among eighteen farms, worked up to seven days per week over three years with little vacation, and periodically walked fields with administrators.
  • He slept in chemical warehouses during rain/delays, near sacks of farm chemicals.
  • Del Monte admitted extensive DBCP injection practices (two annual cycles lasting about two months each; quantified application rates and plant density).

From this, a juror could reasonably infer that Arias was “more likely than not” present during application cycles and experienced inhalation and/or dermal exposure. The court also emphasized that the record supported the biological plausibility of inhalation/dermal routes addressed by the expert.

5. Expert admissibility: why exclusion was an abuse of discretion

The circuit court excluded DiBartolomeis because it viewed exposure as absent and therefore found no predicate “causation in fact” basis. The supreme court rejected that approach as too demanding at the admissibility stage and inconsistent with the summary judgment posture. Under State v. Kim, the expert had a sufficiently “sound factual foundation” (Arias’s testimony plus Del Monte’s DBCP admissions) and relied on scientific literature, including the “Kharrazi Study” (titled in the opinion as Reproductive Effects of Dibromochloropropane, 16 Israel J. Med. Sci. 403, at 404 (1980)).

The court acknowledged the Kharrazi authors’ caution that such epidemiology “can only point to associations,” but treated that limitation as a matter for the factfinder under Dzurik v. Tamura, not a categorical bar to admissibility or to surviving summary judgment.

C. Impact

1. Doctrinal impact: a statewide toxic-tort causation framework

The decision supplies what Hawaiʻi previously lacked: a defined toxic-tort causation approach, grounded in the Restatement (Third), that integrates (a) proof of exposure, (b) agent capability (general causation), and (c) plaintiff-specific linkage (specific causation). This is likely to standardize briefing, expert disclosures, jury-instruction development, and trial court analysis in toxic-exposure cases.

2. Litigation impact: reduced early dismissal based solely on “no precise dose”

By declining rigid dosage proof, the court makes summary judgment less likely in cases where dose cannot be reconstructed but where circumstantial evidence can support reasonable inferences of exposure and medically/scientifically grounded specific-causation opinions can be offered.

3. Gatekeeping impact: stronger focus on reliability/relevance, not “perfect exposure proof”

The opinion reinforces that trial courts must act as gatekeepers (State v. Vliet), but it cautions against using gatekeeping to effectively require definitive exposure proof as a prerequisite to admitting expert causation testimony—particularly where the exposure question is itself a triable factual issue supported by circumstantial evidence.

4. Broader tort-law impact: Restatement (Third) as a development platform

Like Guieb v. Guieb, the case signals continued willingness to use the Restatement (Third) to modernize Hawaiʻi tort doctrine in areas shaped by scientific uncertainty and mass harms.

IV. Complex Concepts Simplified

  • Toxic tort: A personal-injury lawsuit alleging harm from exposure to a toxic substance (chemicals, pollutants, pesticides), often involving scientific proof and long latency periods.
  • Exposure: Contact with the substance (breathing it in, absorbing it through skin, ingesting it). Exposure can be shown circumstantially (work patterns, proximity, storage practices), not only by direct observation.
  • General causation: Whether the substance can cause the type of injury alleged in humans (the “can it cause this?” question).
  • Specific causation: Whether it caused this plaintiff’s injury (the “did it cause this person’s harm?” question), typically requiring expert testimony.
  • “Substantial factor” / frequency-regularity-proximity: Traditional proximate-cause tools used in many negligence cases; the court treats asbestos-style frequency/regularity/proximity as a substantial-factor variant and rejects it as the governing toxic-tort standard in Hawaiʻi.
  • Epidemiology and “doubling of risk”: Group studies can show higher rates of a condition among exposed populations. Some jurisdictions use a “relative risk > 2.0” concept as a proxy for “more likely than not,” but Hawaiʻi declines a rigid rule.
  • Gatekeeping (expert testimony): The judge screens expert opinions for relevance and reliability before the jury hears them; Hawaiʻi applies State v. Kim.
  • Summary judgment: A pretrial ruling that ends a claim only if there is no genuine dispute of material fact; courts must draw reasonable inferences in favor of the nonmoving party.

V. Conclusion

Patrickson v. DOW Chemical Company and Del Monte Fresh Produce N.A., Inc. establishes Hawaiʻi’s modern toxic-tort causation framework: courts should analyze causation through exposure, general causation, and specific causation (in that order), generally requiring expert testimony while rejecting rigid dosage and asbestos-style substantial-factor proxies as categorical barriers. The decision also confirms that where circumstantial evidence supports reasonable inferences of exposure, and expert opinions rest on a sound factual foundation under State v. Kim, the case belongs to the factfinder—not summary judgment.