Hawaii court works in new rules for toxic-tort cases

by Daniel Fisher, Legal Newsline, Sept 23, 2026

(Legal Newsline) - Saying new rules were needed for toxic-tort cases involving large numbers of plaintiffs, the Hawaii Supreme Court ruled plaintiffs in long-running litigation over a Dow Chemical herbicide needn’t prove exactly how much of the chemical they were exposed to.

It is enough to prove plaintiffs have a disease that could be caused by the chemical and that they were in places where it was used, the state high court said in a Sept. 21 decision. The court said the “substantial factor test” in ordinary negligence lawsuits, which requires plaintiffs to identify the specific product and exposure level that caused them harm, is too rigorous for toxic-tort cases where claimants may not know who made the product they were exposed to or how much of it they absorbed.

The ruling came in a lawsuit by a onetime worker on banana plantations in Costa Rica who alleged his fertility was reduced and his wife suffered miscarriages due to exposure to DBCP, a now-banned herbicide made by Dow Chemical. The late plaintiff, Fernando Jimenez Arias, testified he never saw the chemical being applied on fields but was a quality-control inspector who handled bananas and sometimes slept in warehouses where chemicals were stored.

A trial court dismissed his case because Arias failed to present evidence of exposure to DBCP, making the opinion of his expert witness irrelevant. But the Intermediate Court of Appeals reversed, finding there was a fact question for the jury to decide. Dow and the other defendants appealed, urging the court to adopt a rule using the “frequency, regularity and proximity test” found commonly in asbestos litigation. That test requires plaintiffs to prove they were exposed to enough of a substance to cause their disease.

The Hawaii Supreme Court refused to go that far, saying it raised too high a hurdle for plaintiffs like Arias to get over. In a 1991 decision, Smith v. Cutter Biological, the Hawaii Supreme Court decided mass torts required “new rules of causation” because plaintiffs couldn’t be expected to prove which specific manufacturer’s products caused them harm.

The Ninth Circuit Court of Appeals later assumed Hawaii would continue using the substantial factor test in mass torts when in fact the Hawaii Supreme Court had determined in Smith it was unworkable. The court used the Arias decision to confirm a less restrictive test is necessary.

“We decline to adopt any rigid test and instead hold that a plaintiff should offer some evidence `that he or she was exposed to the toxin at issue, including the estimated amount and duration of exposure,’” the court said.

The court declined to use the test in some other jurisdictions requiring plaintiffs to prove they were exposed to a doubling of the risk.

“As we are unable to anticipate factual circumstances of future cases, we refuse to set hard and fast rules regarding the level of exposure required,” the court said. “A juror could reasonably infer that, since Arias worked up to seven days a week with little to no vacation days, it is more likely than not that he was present in the fields when DBCP was applied during the four-month period and inhaled the toxic fumes.

The litigation by foreign plaintiffs over DBCP landed in Hawaii courts because of the long historical ties between the state and fruit growers like Del Monte and Dole.

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This report was produced by Legal Newsline and distributed by The Center Square as part of a content-sharing agreement. Reach editor John O’Brien at john.obrien@therecordinc.com.