An envelope containing the powder arrived at a state Capitol office that processes mail from constituents to state officials. It was not immediately clear Thursday to whom the envelope was addressed.

"We tested the substance and did not find anything to indicate it was toxic," Atlanta fire Capt. Bill May said.

Eighteen state workers who were in and around the room when the powder was found were being evaluated but showed no immediate health effects, May said.

Georgia is the latest in a string of states that have received powder-laced packages in the mail. Envelopes containing suspicious powder have been received this week by governor's offices in Alabama, Alaska, Hawaii, Maine, Michigan, Minnesota, Mississippi, Missouri, Montana, Oklahoma, Rhode Island, South Carolina and Texas.

In Georgia, fire trucks and emergency workers in biohazard suits swarmed a street outside the state Capitol soon after the powder was detected at 12:11 p.m. The first floor office where the substance was found was sealed off but the building was never evacuated.

Georgia Gov. Sonny Perdue was in the Capitol at the time and did not leave, his spokesman Bert Brantley said,

"What we know right now is that it has all the same characteristics of the other ones that we've seen, which have all been false alarms," Brantley said.

Officials said the FBI's Dallas field office would head the investigation.