A badly written and designed drop-down menu was responsible for a mistaken alert that Hawaii was under missile attack according to reports. Local officials will redesign both the menu and the system to reduce the chances of a repeat incident.

The message came from the Hawaiian Emergency Management Agency and appeared on phone screens reading “BALLISTIC MISSILE THREAT INBOUND TO HAWAII. SEEK IMMEDIATE SHELTER. THIS IS NOT A DRILL.” In fact, that’s exactly what it was and it took 38 minutes for the same system to inform readers it was a mistake.

The Washington Post reports the false alarm’s cause was as simple as an employee intending to carry out a scheduled test of the service and choosing the wrong option from the two choices of “test missile alert” and “missile alert”. The system did require a second confirmation click, but the employee either ignored or misread this and confirmed the alert.

To make things worse, there was no standard option in place to send a message recalling the alert as only pre-loaded messages can be sent. (The only option was to block the initial message from continuing to go out to anyone who hadn’t yet received it.) Instead staff had to reconfigure the system to craft a new message saying it was a false alarm and then get “extraordinary permission” to send it, hence the delay.

The incident also highlighted the problem that the emergency alert system is limited to 90 characters, meaning there’s no scope to give useful specific detail or advice.

To minimize the risk of the blunder happening again, the system has now been updated so that one employee triggers the alert and then a second employee must give the confirmation. There’s also a new measure in place to allow a recall message.