The discovery of toxic chemical compounds in Hartford schools has prompted the closure of one school building, and now the city is pursuing litigation to recoup the cost of remediation.

The city has retained Dallas, Texas-based Baron & Budd, a law firm that has represented public entities nationwide whose water supplies, properties, or natural resources are affected by chemical contaminants. The firm on Oct. 23 filed a lawsuit in U.S. District Court on behalf of the city of Hartford and the board of education over alleged polychlorinated biphenyls, or PCB, contamination.

PCB was commonly used in building materials between 1950 and 1979, when it was deemed to be a potential carcinogen and banned. The synthetic chemical served as a coolant for light fixtures and made caulking more pliable. It was also used in paints, sealants and electrical equipment. Though it's found in all types of buildings, its presence in schools has led to a sizable number of lawsuits nationwide.