Earlier today, Hawaiian residents got a disturbing alert on their phones and on television: a missile inbound to the island, and people should take shelter immediately. The notification was quickly confirmed to be false, and Hawaii outlets are reporting that it was sent in error.

The alert, which read “BALLISTIC MISSILE THREAT INBOUND TO HAWAII. SEEK IMMEDIATE SHELTER. THIS IS NOT A DRILL,” alarmed residents, who posted screenshots of the notification on Twitter, and prompted them to take shelter.

The notification was quickly labeled a false report: Hawaii Congresswoman Tulsi Gabbard tweeted a screenshot of the alert, saying that it was a false alarm, and that she had confirmed with officials that there was no danger to the island. Hawaii’s Emergency Management Agency likewise confirmed that there was no threat, and that it was investigating the incident. The US Pacific Command noted that the message was sent in error, and it took more than 30 minutes for authorities to push out a correction.

According to Governor David Ige, the false alarm was determined to be the result of human error:

“This should not have happened. We are investigating the sequence of events that occurred. An error was made in emergency management which allowed this false alarm to be sent. It was a procedure that occurs at the change of shift where they go through to make sure that the system is working and an employee pushed the wrong button.”

The Hawaii Emergency Management Agency released a statement and timeline outlining the issue. It confirmed that the alert was due to human error, rather than the result of an external hack, and explained that it is taking steps to prevent a similar false alarm from occurring in the future.

In the meantime, HEMA says that it will suspend all upcoming drills, that it’s instituted a two-person activation / verification rule for future tests, and has put into place a cancellation command that can prevent a future false alarm from going out.

HAWAII - THIS IS A FALSE ALARM. THERE IS NO INCOMING MISSILE TO HAWAII. I HAVE CONFIRMED WITH OFFICIALS THERE IS NO INCOMING MISSILE. pic.twitter.com/DxfTXIDOQs — Tulsi Gabbard (@TulsiGabbard) January 13, 2018

Despite the quick confirmation that the report was false, the notification is a jarring one for island residents. Given the considerable tensions between the United States and North Korea, such a notification is a nightmare to receive, and could potentially erode trust in the system.

Last year, Hawaiian officials announced that they were preparing to resume the Cold War-era early warning system used to alert residents of an impending attack. Discontinued in the mid-1990s, the tests resumed on December 1st, using a siren that lasts around 50 seconds.

According to the Federal Communications Commission, the Emergency Alert System is a national warning system used by national, state and local officials to address the public, or to deliver emergency information to the public, such as weather emergencies or AMBER alerts to specific areas. FCC Chairman Ajit Pai announced on Twitter that his agency will launch its own investigation.

Update, January 14th, 2018, 8:40AM ET: Updated to include the statement from the Hawaii Emergency Management Agency.