The unnamed employee, who is said to have worked with the Hawaii Emergency Management Agency for over 10 years, had on at least two prior occasions confused a drill with a real-life event, Hawaii Emergency Management officials said.
"Other warning officers who heard the recording in the watch centre report that they knew that the erroneous incoming message did not indicate a real missile threat, but was supposed to indicate the beginning of an exercise", the report said.
Administrator Vern Miyagi and executive officer Toby Clairmont announced their resignation following the release of reports on the errors of the agency. It began, the report said, with a decision by the overnight-shift supervisor to conduct an unannounced drill when the day shift arrived at 8:00 am.
The Federal Communications Commission says carriers must transmit the alerts to more specific locations, rather than broadly. State officials say he was sacked Friday.
He vowed to develop the "best emergency management warning system for our people".
It blamed a lack of proper procedures within the agency to correct the false alert as it was left uncorrected for 38 minutes.
The report said the employee responsible for the erroneous warning message did not realize an order for an emergency drill had been declared, and instead activated a real alert that went out to mobile phones and broadcast outlets across Hawaii.
The employee heard a recorded message that began by saying "exercise, exercise, exercise" - the script for a drill, the FCC said.
While a final FCC report has yet to be issued, their initial probe has revealed that poor planning, inadequate technology and a series of errors from multiple people contributed to and exacerbated the button pusher's mistake.
"While other warning officers understand that this is a drill, the warning officer at the alert origination terminal claimed to believe, in a written statement provided to HI-EMA [Emergency Management Agency] that this was a real emergency, not a drill", the FCC said.
The local authority in the Pacific US State of Hawaii apologized for the false emergency alert, which had caused panic cross the islands and on social media platforms.
According to a report by the FCC, it turns out an unplanned emergency drill was being run at the time and the employee in question - who reportedly has a history of various mishaps - did not get the part of the message that said it was merely a test.
Another issue was that the agency didn't have a plan in case a false alert was sent, Pai said. The report added the Hawaii agency wasn't well equipped to send out a correction and the delay to send one made the mistake even worse.
Following procedures he thought were correct, he activated the state's missile launch alert from a "drop-down" computer menu and, believing an attack was imminent, clicked "yes" when a system software prompt asked, "Are you sure that you want to send this Alert?"
The day shift warning officer who initiated the alert heard "this is not a drill" but did not hear "exercise, exercise, exercise".
The FCC has been investigating the matter and shows a freaky development in the incident, where Hawaiian residents were left scrambling after receiving message about an incoming missile attack.
Hawaii Emergency Management Agency officials work at the department's command centre in Honolulu on December 1, 2017.