A postal worker found white powder on July 15 in about 20 letters addressed to politicians around the country, but officials said preliminary tests found the material was harmless.
Samples of the powder were sent to a state Health Department laboratory, agency spokesman Rob Hayes said. He did not expect final test results for two or three days.
The letters, found at the city's main post office near downtown Tallahassee, were addressed to several members of Congress, said Fire Department spokeswoman Pat Teague. She didn't give names.
After the letters were discovered, a hazardous materials team decontaminated the area. No postal workers were thought to have been exposed to the powder.
Anthrax-by-mail attacks in the fall of 2001, shortly after the September 11 terror attacks, killed five people and sickened many more.