## Facts

- Jacob Anderson owned land in St. Louis County, Minnesota, that was destroyed by fire in October 1918.
- Anderson alleged that in August 1918 sparks from defendants’ locomotive started a bog fire near the railroad right-of-way adjacent to his land.
- According to Anderson’s evidence, the bog fire smoldered until October 12, 1918, then flared up and spread onto his property, causing the destruction.
- At the same time, a large forest fire of unknown origin swept through northeastern Minnesota under severe fire conditions.
- Anderson claimed the locomotive fire either (a) reached his property first, or (b) merged with the other fire and, as part of the combined blaze, destroyed his property.
- Defendants denied causation and contended the destruction was caused by a massive conflagration of unknown origin, pointing to other fires in the area but without clearly tracing the loss to those fires.
- A jury returned a verdict for Anderson; the trial court denied defendants’ motions for a directed verdict and for JNOV or a new trial.

## Issues

1. When a defendant negligently sets a fire that combines with another independent fire of unknown origin, and either fire alone would have been sufficient to destroy the plaintiff’s property, is the defendant liable?
2. Did the trial court err by instructing that causation could be found if the railroad’s fire was a “material” or “substantial factor” in producing the loss, either alone or together with the other fire?

## Decision

- The Minnesota Supreme Court affirmed the order denying JNOV or a new trial.
- The evidence permitted the jury to find that the railroad’s locomotive caused a fire near the right-of-way that ultimately contributed to the destruction of Anderson’s property.
- The challenged instruction correctly stated the causation standard for concurrent sufficient causes: liability may attach if the defendant’s negligent fire was a material or substantial factor in producing the harm, even if another independent fire also contributed and would have been sufficient by itself.

## Legal Principles

- When two causes combine to produce harm and either cause alone would have been sufficient, a negligent actor is not relieved of liability merely because another sufficient cause also existed.
- In multiple-sufficient-cause cases, causation in fact may be established by showing the defendant’s conduct was a material or substantial factor in bringing about the harm.
- Where the competing cause is of unknown origin, requiring strict but-for proof can leave an injured plaintiff without a remedy; the substantial-factor approach permits liability when the defendant’s negligence materially contributed to the loss.
- Causation questions in competing-fire cases are for the jury when the evidence reasonably supports findings on origin and contribution.

## Conclusion

The court upheld the verdict for the landowner, holding that a railroad whose negligence started a fire remains liable if that fire was a substantial factor in the destruction, even when it merged with an independent fire of unknown origin and either fire alone could have caused the loss.


Anderson v. Minneapolis, St. P. & S. St. M. Ry. Co., 179 N.W. 45 (Minn. 1920)