But state officials said they will review lapses in communication that left them to learn of the possible threat from evening news broadcasts.

Laboratory tests on a suspicious white, powdery substance found at the Atlanta Army facility Friday afternoon confirmed late Saturday that it is not anthrax, despite initial field tests that were positive for the deadly bacterium.

"The definitive result is that it is not anthrax," said Lisa Swenarski, spokeswoman for the U.S. Centers for Disease Control and Prevention in Atlanta, where the substance was tested.

Activities at the post in southwest Atlanta were back to normal Saturday afternoon, except for the U.S. Army Reserve Command headquarters building, where the substance was discovered in a fourth-floor closet. The building remained closed while the substance was being tested, said Lt. Col. Ken Konstanzer, a spokesman for the U.S. Army Forces Command, which is located on the base.

The suspicious package was found shortly after 5 p.m. Friday, military officials said. But it was unclear how the package got into the building or how long it had been there, despite earlier reports that it had been delivered through the front door.

Joe Handley, a spokesman for Reserve Command headquarters, said the package was a plastic, sandwich-type bag that contained a white, powdery substance.

The package "could be anything that fell out of someone's pocket," said Col. Guy Shields, chief of public affairs for Forces Command.

Seven people, five civilians who work in the Reserve Command building and two firefighters who responded to the call, were exposed to the substance, military officials said. All were decontaminated on the scene and sent home. They were notified late Saturday that they had not been exposed to anthrax, said Sgt. 1st Class Johnny Beatty, a spokesman for Forces Command.

The building was shut down after the substance was found and about 200 of the 1,000 civilian and military employees who work there were kept inside until about 9 p.m. Friday.

Officials at the two key state agencies charged with response to bioterrorism said Saturday that they heard about the discovery of the suspicious substance from television before they were contacted by federal authorities.

"We did send someone last night when we first heard about it. Their response was that no assistance was required from us," said Georgia Emergency Management Agency spokeswoman Lisa Ray. GEMA operates a 24-hour-a-day center designed to be the state communications hub for responding to threats ranging from tornados to terrorist attacks, Ray said.

Officials at the state public health department's Bioterrorism Unit also said during the first hours of the incident they knew only what they were hearing from media reports. The state Homeland Security Task Force will review the incident for ways to improve communication in future incidents, Ray said.

Georgia was among eight states selected Saturday by the National Governors Association for assistance in developing its homeland security and bioterrorism plan. The assistance program, funded by the CDC, FEMA and the Department of Justice, will focus on helping state terrorism programs improve coordination with federal and local governments, Kentucky Gov. Paul E. Patton said.

Cars entered and left through the Fort McPherson main gate after undergoing cursory security checks Saturday. Groups of golfers were playing the post's course.

"I went to my regular 9 o'clock meeting," Shields said. "The PX is open. The only thing that is unusual is that the building is sealed." The building would normally be staffed on Saturday, he said.

Officials were not classifying the incident as a hoax, although there have been a number of them at military bases, government office buildings and abortion clinics since Sept. 11. Beatty said the FBI was one of the first agencies on the scene Friday and is investigating. FBI officials in Atlanta did not return telephone calls Saturday.

Swenarski said "There are many more hoaxes than there are actual deliveries of anthrax, but we have to take each one seriously."

The military has tightened its mail-screening procedures since last fall, when five people died after letters containing anthrax were mailed to media outlets and government offices in Florida, New York and Washington.

But "there is no indication that this came in the mail," Konstanzer said Saturday.

Everyone entering the Reserve Command headquarters must have a badge and visitors must sign in and be accompanied. Shields said the base had not yet reviewed its security procedures because it is not yet clear if security was breached.

"When we get the final report we'll review all of the procedures," Shields said. "We'll make changes if we need to make changes."