Bristol Police Chief Kevin Lynch confirmed that the Bristol Warren Regional School District administration building was evacuated Wednesday afternoon because a district employee opened an envelope and letter that contained a white, powdery substance.

He said employees evacuated the building, per protocal, before first-responders even arrived. Over the following three hours, firefighters and police officers from Bristol taped off the building and the area around the building, on State Street across from the Bristol Town Common, and waited for special Haz-Mat crews from East Providence and North Providence to set up, gear up and enter the building.

Chief Lynch said they were waiting for crews to examine the substance before being able to investigate the letter, its content or its sender.

While the process continues, administration employees have been kept inside a yellow school bus that was brought to scene when they evacuated.