The mail processing room at the Internal Revenue Service building on Lowell Street was placed in lock down Monday morning after a white powdery substance was reported being released from an envelope.
A hazardous materials team was requested to respond to the building at 310 Lowell St. shortly after 10:30 a.m. The 30 employees working the processing room at the time were placed in isolation, according to a press release from the fire department.
Fire Chief Michael Mansfield said there was no evacuation of the building, There are about 860 employees who work in the building, according to IRS spokeswoman Peggy Riley.
At 12:30 p.m., it was determined the 30 employees could exit the isolation area after being briefed, Mansfield said.
He said the mail was examined by hazardous material technicians and there was no indication the substance came from the envelope.
There was no threat received or any evidence of a threat found in the involved mail, the release said.
"It appears we are dealing with a residue of a prescription drug," Mansfield said. "We are not viewing this as an act of malice."
The incident was under control by 2:45 p.m. The remainder of the substance was recovered and sent to a laboratory for further analysis and identification.