All Ears for a Blast From the Past

"We don't want to disturb people," Griffin said, "but we want to make sure we get the best information we can." He estimated the project's cost at $350,000.

Most local governments dismantled their civil defense sirens in the 1990s after the federal government withdrew funding for them when the Cold War ended. They had alerted the public to emergencies for a century, starting with fire alarms. After World War II, they were named civil defense sirens throughout the United States after Joseph Stalin tested the Soviet Union's first atomic bomb in 1949.

With the threat of nuclear war over, some of the yellow, electrically powered mechanical devices stayed as warning systems in some parts of the country for tornados and other natural disasters. Around Washington today, they are used near the Calvert Cliffs nuclear power plant to warn of any accidents and by eight tiny firehouses in western Loudoun County to summon volunteers to duty.

The new generation of sirens, according to a study conducted by George Washington University for the Metropolitan Washington Council of Governments, can be used to send live or recorded messages in multiple languages. They're more reliable than the older generation, and they can operate on batteries. They can be tested silently. And they can be activated individually -- after a chemical spill in one neighborhood, for example -- or as a group.

Some officials fear that with so many features, the technology could confuse people in an emergency, even if there was a thorough campaign to educate the public. "It used to be that a siren meant a tornado, and everybody knew that," said Fairfax County spokeswoman Merni Fitzgerald, who also heads the county's emergency communications efforts. "In this day and age, it's not going to just be, 'We'll notify you if it's a tornado.' It could be a bomb. People might say, 'That's a loud noise -- what does it mean?' "

Officials of other local governments say they are watching the experiment carefully. The District dismantled its 100 civil defense sirens in the early 1990s, but a few remain in the city, including at George Washington University and Bolling Air Force Base.

Just 13,500 residents have signed up for an electronic alert system since its rollout 18 months ago. The city is "open to anything . . . that might help alert our residents of an emergency incident," said Jo'Ellen Countee, spokeswoman for the emergency management department.

"We're really looking forward to seeing the results," said Scott Reilly, assistant chief administrative officer in Montgomery County, which with its large agricultural reserve spans 500 square miles. He said he has concerns, though: "I'm not sure how a siren reaches into buildings or a shopping mall."