A federal appeals court upheld a lower court ruling in a Liberty Mutual Insurance Co.’s unit favor Tuesday, ruling the insurer does not have to indemnify a plaintiff who became ill after he inhaled silica sand, based on a policy exclusion.

Philip Mauro became ill while working as a construction supervisor on a jobsite with Philadelphia-based Diamond Contact Flooring LLC, at the Philadelphia Airport Marriott, according to the ruling by the 3rd U.S. Circuit Court of Appeals in Philadelphia in Philip Mauro, as assignee for Diamond Contract Flooring, LLC v. Ohio Security Insurance Co.

After he was treated for chronic obstructive pulmonary disease, Mr. Mauro sued Diamond in state court, claiming the company’s use of Novoplan Easy Plus to level the concrete floor caused his illness.

Diamond sought coverage from Liberty Mutual unit Ohio Security, which refused to provide a defense citing a policy exclusion that precluded coverage for injury arising from the inhalation of “silica” or “silica-related dust.”

Diamond then assigned its right under the policy to Mr. Mauro.  Mr. Mauro won a $375,000 award against Diamond, then sued Ohio Security.

The U.S. District Court in Philadelphia ruled in Ohio Security’s favor and was affirmed by a three-judge appeals court panel. “The main dispute involved a question of contract interpretation: whether silica sand – the only silica product listed on Novoplan’s Safety Data Sheet – fell within the Exclusion” in the policy for silica or silica-related dust.

On the same page as the exclusion, the policy defines “silica” as “silicon dioxide…silica particles, silica dust or silica compounds,” and defines “silica-related dust” as “a mixture or combination of silica and other dust particles,” the ruling said, in concluding the district court “properly held that the Exclusion unambiguously precludes coverage for Mauro’s injuries arising from silica sand.”

Attorneys in the case did not respond to requests for comment.

In May, a federal appeals court affirmed a lower court ruling in favor of an Iowa reinsurer in a dispute with a Munich Re unit over cleanup and property damages related to construction that created silica dust.