It was an an external battery charger for electronic devices and toppled stanchions — not an exploding laptop computer — that triggered pandemonium and long airline flight delays in Honolulu’s main airport terminal Tuesday, state officials said today.

Hawaii Department of Transportation officials said a detailed review of the incident found that the external battery charger overheated and melted a foam neck pillow in a traveller’s carry-on luggage to produce smoke.

Then, some stanchions used to keep travelers in line fell over during an effort by Transportation Security Administration officers to clear the checkpoint amid the smoke and keep passengers safe, DOT said, adding that the toppled stanchions made a “pop, pop, pop” sound that caused some travelers to mistakenly think a gun was being fired.

“Passengers panicked and started running into the sterile area,” transportation officials said in a news release, adding that this caused a security breach that required the terminal to be cleared.

The event resulted in more than 40 flights being delayed, thousands of customers inconvenienced and some minor injuries.

State and federal officials reopened an adjacent terminal at about 6 p.m., nearly four hours after the incident began, after a TSA and state sheriffs security sweep of the airport and aircraft using explosive-detection canines.

It wasn’t until 9 p.m. that all TSA screening operations and security checkpoints were back to normal operations, DOT said.

Transportation officials thanked the traveling public for its patience, and said airport stakeholders continue to meet this week to review details of the incident and determine whether any changes to airport security plans are necessary.