Several workers complained of headaches after a white powder came out of an envelope sent to the Florida state attorney's office Tuesday.
Police responded to the West Palm Beach office around 9:00 a.m. after the envelope was found to have a white powdery substance in it.
Three people working in the mail room complained of headaches, nausea and vomiting. A firefighter who responded suffered cardiac symptoms.
All those affected were taken to an area hospital for treatment.
Field tests on the powder came back inconclusive. The substance is being sent to an FBI lab for further testing.