Read our special on travel to the USA

Security screening for arriving passengers has been stepped up yet again at American airports, but The Sunday Times has learnt of worrying flaws in new fingerprint-scanning technology.

Last week, Logan airport, in Boston, became the third US airport to install the 10-finger scanners. Dulles airport, which serves Washington, DC, began using the devices in November and Atlanta airport began this month. By the end of the year, the devices will be installed at every international airport in the USA, as well as at seaports and border crossings.

NonUS residents have had two fingers scanned on entry since 2004, but the Department of Homeland Security believes the 10-finger standard will allow easier identification of undesirables, based on full or partial prints left at the scene of a crime or collected from terrorist safe houses or battlefields.

Travel to America? No thanks

It’s already a nightmare, but now they want to make entry into the USA tougher. So let’s not go says Matt Rudd

• Problems exiting the US

Described by Identix, their manufacturer as “slap and roll” technology, the scanners require four scans to capture a full set of prints. These are then compared with more than 3.2m fingerprints held in the FBI and Department of Defense databases.

Identix claims that the scanner can perform its duties in “less than 15 seconds”. It says “you do need to be a trained fingerprint expert” to use the machines, and while operators at Atlanta have reported only “teething troubles” with the new equipment, the system has caused problems in the past.

In 2003, Californian Roger Benson filed a lawsuit after he was stopped by police for a traffic violation and fingerprinted using the same scanner. His prints were incorrectly matched with a convicted felon and he served 43 days in prison.

Miguel Espinoza brought a lawsuit against Identix in 2004 after his prints were wrongly assigned to a convicted murderer. The case was dismissed after the judge ruled that human error, and not the scanner, had caused the mix-up, but human-rights groups say overdependence on technology will continue to put travellers at risk.

Last July, a US government report found that “systems supporting the US-VISIT program have significant information security control weaknesses”, but homeland security chief Michael Chertoff is an enthusiast. “Moving to 10 fingerprints is completely consistent with, and in fact enhances, our ability to protect,” he said.