State and local authorities are examining a state agency building after a suspicious letter was discovered, forcing some 1,500 employees to evacuate.
The letter was found Monday inside the state's highway safety building - four miles east of the Florida Capitol.
A Tallahassee Fire Department official told reporters that writing on an envelope found in the records office indicated anthrax was inside. But nothing was inside the envelope, which was addressed to the agency's executive director.
Employees were told to return later Monday.
The letter was handed over to the Florida Department of Law Enforcement for further examination, then transported by the Florida Department of Health to a lab in Jacksonville. It will be analyzed for anthrax.
Seven employees were examined for signs of contamination.
The incident comes as Mississippi officials charged a new suspect with sending letters containing ricin to President Obama and others.