US Customs and Border Protection (CBP) started 2018 with an unintentional two-hour shutdown of its computer system the evening of Jan. 1, generating significant delays at several US airports for passengers arriving from international originating points.

CBP issued a statement at about 10:30 p.m. indicating all affected airports were back on line “after a temporary outage of CBP’s processing systems.”

CBP said there was no indication that the disruption—which began at approximately 7:30 p.m. EST and ended at about 9:30 p.m.—was malicious in nature. “During the disruption, CBP had access to national security-related databases and all travelers were scanned according to security standards,” CBP said.

In its official statement, CBP said it “took immediate action to address the technology disruption. CBP officers continued to process international travelers using alternative procedures at affected airports. Travelers at some ports of entry experienced longer than usual wait times as CBP officers processed travelers as quickly as possible while maintaining the highest levels of security.”

NBC News quoted CBP describing the problem as “standard [self-service] CBP technology [that] was unable to recognize who was a US citizen, a resident and who was just a visitor.” NBC said passengers posted photos on social media of long queues at Hartsfield Jackson Atlanta International Airport (ATL). New York JFK and Miami International Airport (MIA) both issued statements on social media alerting passengers of the CBP processing delays.

The incident came two weeks after an 11-hour power blackout at ATL, the world’s busiest airport, forced Atlanta-based Delta Air Lines to cancel 1,400 flights—disrupting thousands of passengers, airline crews, airport personnel and hundreds of flights worldwide—at the outset of the 2017/2018 holiday flying season.

One year ago, on Jan. 2, 2017, a technical outage affected CPB’s passenger processing at multiple US airports, creating a similar delay situation for thousands of passengers returning from the holidays. CBP told ATW at the time that a software update initiated a few days prior to the 2017 outage was the reason behind the incident.

ATW asked CBP about the similarities between the two incidents one year apart; a CBP spokesperson replied with no comment beyond the agency’s official statement.

Mark Nensel