## Facts

- Thomas A. Bockrath worked at Hughes Aircraft from 1973 to 1994 and later developed multiple myeloma.
- He sued Aldrich Chemical Co. and more than 50 other manufacturers/suppliers, alleging exposure over 21 years to hundreds of chemical products used or present at the plant.
- The operative second amended complaint alleged he and coworkers used “most, and perhaps all” defendants’ products, causing inhalation and skin contact; it also alleged remaining products were used or stored elsewhere and circulated through ventilation, so the environment contained “all” products.
- The complaint pleaded general assertions that the chemicals were carcinogenic and, after metabolic transformation, migrated to bone marrow and caused injuries that initiated or promoted multiple myeloma.
- In discovery responses subject to judicial notice, Bockrath admitted he could not identify which particular chemicals caused his illness and did not proceed under alternative-liability or market-share theories.
- The trial court sustained defendants’ demurrers for failure to plead causation adequately and entered judgment for defendants; the Court of Appeal affirmed.
- The California Supreme Court granted review to determine how causation must be pleaded in long-term, multi-toxin exposure cases.

## Issues

1. In a toxic-exposure case involving many defendants and products, what specificity must a complaint plead on causation to survive demurrer under California fact-pleading rules?
2. How must the “substantial factor” causation standard be reflected in pleadings when the plaintiff alleges cumulative exposures caused a disease?

## Decision

- The court held the complaint’s causation allegations were insufficiently specific and the demurrers were properly sustained.
- The court held the plaintiff should have been granted leave to amend because there was a reasonable possibility he could plead additional defendant- and product-specific facts.
- The matter was remanded with directions to allow amendment consistent with the court’s causation-pleading requirements.

## Legal Principles

- California applies the “substantial factor” test: a cause must be more than infinitesimal or theoretical, need not be the sole cause, and may operate with other causes to produce harm.
- In multi-toxin disease cases, cumulative causation is permissible in theory, but a plaintiff must still plead nonconclusory facts linking each defendant’s product to the injury.
- A complaint must allege, as to each defendant’s product, facts supporting: (a) exposure (time, place, and manner), (b) the product’s capacity to cause the type of harm alleged (general causation), and (c) that the exposure in fact caused or contributed to the plaintiff’s disease (specific causation) such that the product was a substantial factor.
- Omnibus allegations that “all” products were present and “all” caused the disease, without differentiating among products, chemicals, or defendants, are conclusory and inadequate to state causation.
- Denial of leave to amend is improper where the plaintiff shows a reasonable possibility of curing the pleading defects; doubts are resolved in favor of allowing amendment.

## Conclusion

The court required defendant-specific, fact-based pleading of substantial-factor causation in long-term, multi-toxin exposure litigation, upheld dismissal of conclusory global allegations, and ordered that the plaintiff be given an opportunity to amend to plead exposure and causation with sufficient specificity as to each defendant and product.


Bockrath v. Aldrich Chem. Co., 21 Cal. 4th 71 (Cal. 1999)