Rutherford v. Owens-Illinois, Inc.

Supreme Court of California · 1997 · Torts

16 Cal. 4th 953 (1997)

Updated July 23, 2026

TortsProducts liabilityCausationAsbestos litigationasbestoslung cancersubstantial factorreasonable medical probability

Facts

Charles Rutherford worked for decades at Mare Island Naval Shipyard and was exposed occupationally to asbestos dust from multiple asbestos-containing products. After he died of lung cancer, his family pursued wrongful death claims, and medical evidence showed asbestos-related lung cancer is dose-related, with multiple occupational exposures contributing to risk. In the liability phase, plaintiffs elected to use Solano County General Order No. 21.00, which shifted to Owens-Illinois the burden to prove its Kaylo insulation was not a legal cause once plaintiffs proved defect, asbestos-caused injury generally, and exposure to Kaylo. The jury assigned Owens-Illinois 1.2 percent fault and plaintiffs obtained a net judgment against it.

Issue

In an asbestos-related cancer products liability case, may a trial court instruct the jury that once the plaintiff proves defect, general asbestos causation, and exposure to the defendant's product, the burden shifts to the defendant to prove its product was not a legal cause of the injury? If that instruction was improper here, was the error prejudicial?

Rule

In asbestos-related cancer cases, the plaintiff bears the burden to prove threshold exposure to the defendant's defective asbestos-containing product and to prove, in reasonable medical probability, that the exposure was a substantial factor in causing the injury. The plaintiff need not prove that fibers from the defendant's product actually initiated the malignancy; causation may be shown by evidence that the exposure was a substantial factor contributing to the plaintiff's aggregate dose and thus to the risk of developing cancer. A burden-shifting instruction based on alternative liability is generally unnecessary and incorrect in such cases.

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One of 10 multiple-choice questions for this case. Pick an answer to see why.

Luis Moreno worked for 22 years renovating boiler rooms in Cleveland, where he inhaled dust from multiple asbestos-containing insulation products made by different suppliers. After he develops asbestos-related lung cancer, his expert testifies that the defendant's insulation materially added to Luis's cumulative asbestos dose and, in reasonable medical probability, substantially increased his risk of developing cancer, but cannot identify which fibers actually triggered the malignant cells.

Has Luis presented sufficient evidence of causation against that defendant?

Explanation. In an asbestos-related cancer case, the plaintiff must prove threshold exposure to the defendant's defective asbestos-containing product and must show, in reasonable medical probability, that the exposure was a substantial factor in causing the injury. The majority held this burden may be satisfied by evidence that the exposure substantially contributed to the plaintiff's aggregate dose and therefore to the risk of developing cancer. The plaintiff need not prove the defendant's fibers were the ones that actually began the malignant process, and no burden shift is required.