Four people were transported to the hospital as a precaution on Friday after officials say an unknown substance was discovered at the federal courthouse in Milwaukee. An investigation found there to be no evidence of anything hazardous.
WATCH: MFD assistant chief provides latest update on Milwaukee federal courthouse hazmat situation
According to Assistant Chief Schuyler L. Belott, individuals opened an envelope and reported a "powder of some sort" inside the letter around 2 p.m. According to the U.S. Marshals Service, the package was delivered to the U.S. Secret Service field office at 517 E. Wisconsin Ave.
In response, a large number of police and fire department personnel responded to the courthouse, including the hazmat response team.
Based on the conditions, Belott says employees were sheltered in place during the investigation.
Four people were evacuated from one office, decontaminated outside the building, and then transferred to the hospital as a precaution. No one was experiencing any symptoms.
Belott says there was no evidence of anything hazardous and there was no threat.
It is unclear who the envelope was addressed to.
The Hatmaz process is deliberate and takes time, Belott said.
TMJ4 News also spotted a drone from the Milwaukee Fire Dept. and a yellow tent. At the scene, TMJ4 News spotted people wearing white protective Hazmat suits.
The scene stretched across the federal building and courthouse area at Jackson and Wisconsin in downtown Milwaukee.
This is a developing story. This report will be updated with the latest information.
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