Around 3pm the Atlanta Airport’s emergency alert system started flashing lights saying there is an emergency in the building and that we will be notified of further instructions. This announcement played for about 5-10 minutes at a time and the exact same announcement played about every 30-45 mins. The fire in the building may have triggered this alarm given that it didn’t come on until hours after the power was out. This was the only light we had in Terminal B. This announcement caused some anxiety among passengers because no one notified us of what the emergency in the building was. Most assumed it was the power outage but many people were worried of a possible terrorism threat. No official had ever told us about the fire in the building or that they were evacuating other terminals or to stay in Terminal B. We were told that we could not leave the building at this time by an employee.