Four alarming minutes
"Urgent. All stations. This is an attack warning. . . Take appropriate action."
At 11:14 a.m. last Wednesday, the Pennsylvania emergency management agency in Harrisburg relayed that message to 44 county civil defense agencies. A conscientious civil defense worker in Lehigh County set off the nuclear-attack sirens and was about to contact the Emergency Broadcast System, which warns localities of a nuclear attack, when at 11:18 a.m. he received another message: "Disregard."
The warning was accidentally sent out by two Harrisburg AT&T technicians who were installing new emergency teletype equipment. Most...