A suspicious white powder mailed to the Palm Beach County State Attorney's Office is not hazardous.
The FBI said Wednesday that testing on the substance discovered a day earlier in West Palm Beach showed it not to be harmful. An initial test was inconclusive.
The Palm Beach Post reports the new tests mean all four people who had been hospitalized in the incident will be released.
Three people who work in or near the mailroom where the powder was found in a letter complained of headaches and nausea. A firefighter who responded to the scene reported cardiac problems.
No suspect has been named in the incident. The FBI says its investigation is ongoing.