A carry-on bag caused long lines at Sea-Tac checkpoints Sunday night

A carry-on bag caused a security breach, long lines and delays to get to the gate at Seattle-Tacoma International Airport on Sunday night.

At 7:55 p.m. Sunday, an equipment malfunction at a security checkpoint prevented a passenger’s carry-on bag from being properly searched, Transportation Security Administration spokesperson Lorie Dankers said.

Dankers did not say why the person’s bag needed to be searched. But she said any bag must be physically inspected if it appears on X-ray image to contain “a potential security threat.” She did not elaborate on what the threat was.

TSA stopped security screenings while Port of Seattle police officers searched for the passenger and bag in the gate area of the terminal. Using security footage, officers identified the person and escorted him back to the checkpoint for rescreening, Dankers said.

All security screenings resumed at 8:20 p.m.

TSA is investigating why the bag wasn’t “properly diverted” for further examination, according to Dankers.

Pausing security screenings is “standard protocol any time one of these breaches happen,” said Chris Guizlo, a Port of Seattle spokesperson.

Sunday marked the third disruption at Sea-Tac in less than a week.

Last Monday, police arrested 46 protesters who were calling for an end to the Israel-Hamas war for blocking the road leading to the airport. On Wednesday, Alaska Airline flights were grounded for an hour due to an issue found while the company was performing an “upgrade to the system that calculates our weight and balance.”

Seattle Times staff reporter Catalina Gaitán contributed to this report.