In a 5-2 decision authored by Justice Ziegler, the Wisconsin Supreme Court determined that a homeowner’s insurance policy excluded coverage for bat guano, because damage from such a substance was excluded as a “pollutant.”
The Hirschhorns owned a vacation home in Lake Tomahawk, which was discovered in 2007 to be infested with bats, whose excrement lined the space between the siding and the walls. They paid to have the guano removed, but the “penetrating and offensive odor” persisted. Auto-Owners denied their claim for coverage.
Under the insurance contract, damage caused by the “discharge, release, escape, seepage, migration or dispersal of pollutants” was excluded from coverage. “Pollutants” was defined as “any solid, liquid, gaseous or thermal irritant or contaminant, including smoke, vapor, soot, fumes, acids, alkalis, chemicals, liquids, gases and waste. Waste includes materials to be recycled, reconditioned or reclaimed.”
Using extensive citation to dictionaries and reference to a handful of similar cases, the court held both that the guano was a pollutant (because it was both an irritant and a contaminant) and that the guano and its odor had discharged, released, escaped, seeped, migrated and/or dispersed throughout the property, thus triggering the exclusion clause.
Chief Justice Abrahamson, joined by Justice Bradley, dissented. She believed that the term “pollutant” was ambiguous, did not clearly include bat guano, and therefore should have been interpreted in favor of coverage.