The Sebastopol Regional Library has shuttered indefinitely.

A Bay Area library closed indefinitely on Thursday under mysterious circumstances, during a time when it would normally see a surge of summer readers fresh out of school. 

In a Friday news release, the city of Sebastopol and the Sonoma County Library announced staff were investigating an "environmental concern” that shut down the Sebastopol Regional Library branch at 7140 Bodega Avenue. Officials hired experts to evaluate and conduct testing inside the library, but did not provide further information regarding what had happened and said results would be provided later this........

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