LOUISVILLE, Ky. (WDRB) -- Officials are investigating after a powdery substance brings a scare at Frazier Rehabilitation Center in downtown Louisville.

Someone found an envelope with the brown, powdery substance in a 15th floor office Tuesday afternoon, said Louisville Fire and Rescue Capt. Sal Melendez.

Workers called for help about 4 o'clock, and hazardous materials crews tested the powder. They found it was harmless. No one was hurt. The six people initially exposed to the substance did not show any symptoms of illness, Melendez said.

"They found that it was a cleaning-type of material found in an envelope. Such an envelope was discovered through the internal mailing system, that's where it was found," Melendez said.

Crews isolated the one office where the envelope was delivered. There was not an evacuation, Melendez said.

"There is no threat, and we're doing everything according to procedure at this point," said Kentucky One Health Director of Safety Scott Mandel.

The fire department has notified the FBI for further investigation. That is standard procedure in such cases, Melendez said.

Metro police blocked Abraham Flexner Way its entire length from Brook to Floyd Streets and restricted access to some, but not all pedestrians on public sidewalks in the block.

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