## Facts

- Charles J. Sternhagen worked for a crop-spraying business in northeast Montana from 1948–1950 and was exposed to the herbicide 2,4-D.
- In 1981, Sternhagen (a radiologist) was diagnosed with cancer; he later died. His estate alleged the cancer was caused by the 1948–1950 exposure.
- Marlene L. Sternhagen, as personal representative, sued multiple chemical companies in federal court, alleging each separately manufactured the 2,4-D products to which Sternhagen was exposed.
- Defendants asserted that, at the time of manufacture and sale in the late 1940s, scientific and industry knowledge did not indicate 2,4-D was carcinogenic.
- Defendants sought to introduce “state-of-the-art” evidence to show they neither knew nor had reason to know of any cancer risk at the relevant time.
- Plaintiff argued that, under Montana strict products liability, the manufacturer is treated as knowing the inherent dangers of its product, making state-of-the-art evidence irrelevant and inadmissible.

## Issues

1. In a Montana strict products liability action involving an inherently unsafe product, may a manufacturer introduce state-of-the-art evidence to negate knowledge or foreseeability of the product’s danger?
2. Alternatively, is the manufacturer conclusively treated as knowing the dangers inherent in its product, rendering state-of-the-art evidence inadmissible?

## Decision

- The Montana Supreme Court answered the certified question by holding that state-of-the-art evidence is not admissible to show what the manufacturer knew or could have known in strict products liability.
- The court held that, for strict liability purposes, the manufacturer is treated as if it knew or should have known of the dangers inherent in its product.
- The court returned the matter to federal court for further proceedings consistent with this rule of Montana law.

## Legal Principles

- Montana strict products liability focuses on the condition of the product (defect and unreasonable danger), not the manufacturer’s conduct, fault, or knowledge.
- State-of-the-art evidence is generally pertinent to negligence because it bears on reasonableness under then-existing knowledge; it is not admissible to negate liability in Montana strict products liability.
- Permitting state-of-the-art evidence in strict liability would reintroduce negligence concepts and shift the inquiry toward whether the manufacturer acted reasonably.
- Strict products liability allocates the costs of product-caused injuries to entities that market products and can spread losses through pricing and insurance, rather than to injured consumers.

## Conclusion

The Montana Supreme Court held that a manufacturer defending a strict products liability claim may not use state-of-the-art evidence to argue that a risk was scientifically unknowable at the time of sale; Montana treats the manufacturer as knowing the inherent dangers of its product, keeping strict liability distinct from negligence.


Sternhagen v. Dow Co., 282 Mont. 168, 935 P.2d 1139 (Mont. 1997)