## Facts

- Joseph and Agnes Waschak owned a home in Taylor, Pennsylvania, a residential area within an anthracite coal-mining community.
- Robert Y. Moffat and W. K. Moffat operated a coal-breaking business and maintained culm (coal refuse) banks near the Waschaks’ property.
- Hydrogen sulfide gas emitted from two culm banks drifted onto the Waschaks’ property.
- The gas discolored the exterior paint of the Waschaks’ house, turning white paint a dark, scorched-like color, and caused odor-related discomfort.
- The Waschaks sought damages primarily limited to the cost of repainting.
- The Moffats did not dispute causation but contended their operations were customary and non-negligent, the emissions were unintentional, and the activity was not ultrahazardous.
- The trial court awarded the Waschaks $1,250; the Superior Court affirmed.

## Issues

1. Whether a coal operator is liable in private nuisance for a non-trespassory invasion (gas emissions causing property damage and odors) when the invasion was neither intended nor substantially certain, and the conduct was not negligent, reckless, or ultrahazardous.
2. How “intentional and unreasonable” interference is defined for private nuisance purposes where the defendant intended only to conduct ordinary industrial operations.

## Decision

- The Supreme Court of Pennsylvania reversed and entered judgment for the defendants.
- The court held the interference was not “intentional” because the defendants did not know, and were not substantially certain, that their conduct would cause the specific harm.
- The court held the interference was not “unreasonable” given the customary nature and social utility of coal operations in the community and the limited nature of the harm.
- The court found no basis for liability under negligence, recklessness, or ultrahazardous-activity theories.

## Legal Principles

- A private nuisance claim for a non-trespassory invasion requires proof that the invasion is either:
  - intentional and unreasonable, or
  - unintentional but otherwise actionable under rules governing negligent, reckless, or ultrahazardous conduct.
- An invasion is “intentional” in nuisance only if the actor knows, or is substantially certain, that the interference will result; intent to operate a lawful business is not enough.
- Unreasonableness is assessed by weighing the gravity of harm against the utility of the defendant’s conduct and the character of the locality.
- Ordinary, customary industrial activities in a mining region are not treated as ultrahazardous merely because they occasionally cause incidental harm, absent proof supporting strict liability classifications.
- Limited, repairable property damage and incidental discomfort may be insufficient to establish an unreasonable interference where the defendant’s use is normal for the community and the harm was not foreseeable.

## Conclusion

The court denied recovery for paint damage and related discomfort because the gas emissions were not shown to be a known or substantially certain result of the defendants’ customary coal operations, and plaintiffs failed to prove an intentional and unreasonable nuisance or an otherwise actionable unintentional invasion grounded in negligence, recklessness, or ultrahazardous activity.


Waschak v. Moffat, 379 Pa. 441, 109 A.2d 310 (Pa. 1954)