PORTLAND, OR (KPTV) -
The FBI and a Portland hazmat crew responded to this week's fourth and fifth cases of a suspicious white powder Thursday.
Firefighters responded to an office building at Southwest Fourth Avenue and Market Street at around 12:30 p.m.
Two people in the building came into contact with white powder in an envelope. Those people were quarantined on the fifth floor of the office building, and the rest of the floor was evacuated.
Hazmat crews conducted tests on the powder to determine what it is and eventually determined it wasn't a toxic substance.
Officials shut down roads in the area as a precaution.
At around 4 p.m. Thursday, a fifth white powder envelope was found at the Marquam Plaza Medical Building at Southwest Third Avenue and Sheridan Street in Portland. Firefighters and hazmat crews responded to an OHSU human resources office there.
This comes after three other white powder incidents in a four-day span. In all cases, the powder was determined to not be harmful.
But in at least one case, at the offices of the Port of Portland, the word "anthrax" was found on an envelope. All three floors of the offices were evacuated, but Portland International Airport terminals and travel were not affected.
The FBI is investigating whether the same person or group is responsible for all of the letters.
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