The customs preclearance facility the U.S. Customs and Border Protection (CBP) agency established last January at Abu Dhabi International Airport prohibited 450 people from boarding flights to the United States in its first year of operation. Some of those people were suspected terrorists, said Homeland Security Secretary Jeh Johnson, who wants to expand the network of preclearance facilities to other locations.

The Department of Homeland Security (DHS), the CBP’s parent organization, now oversees 15 such facilities and has made customs preclearance “a big agenda item,” Johnson said in a speech to the Aero Club of Washington on January 16. “We’re seeing considerable productivity in terms of the level of screening, and a number of people are being identified and not allowed to board at a number of these airports,” he added. “I think it’s important any time we can push out our homeland security beyond our borders.”

By screening people earlier in the travel cycle, the DHS believes it can better protect against high-risk passengers seeking entry to the U.S. and also help relieve long customs lines at arrival airports. But U.S. airline industry groups strenuously opposed its latest facility opening at Abu Dhabi’s airport, arguing that it would benefit only government-owned Etihad Airways, giving it an advantage over other carriers. Other U.S. customs preclearance facilities are located in Canada, Ireland and the Caribbean.

Etihad announced on January 12 that travelers on all of its flights to the U.S. now have access to the customs preclearance facility at Abu Dhabi airport. “Since its opening in January last year, the U.S. preclearance has been extremely popular with air travelers, particularly those from the Indian subcontinent and Middle East region,” the carrier said. “More than 325,000 people have passed through the facility, arriving in the United States as domestic passengers.”

Johnson in his speech used a different number, saying the CBP facility screened 290,000 passengers, in addition to flight crews, in its first year of operation. Of that amount, “450 individuals were denied boarding, including several in the terrorist screening database.”

After opening the Abu Dhabi facility, the DHS issued a solicitation for other potential preclearance sites overseas. It received letters of interest from 25 airports, reported Johnson, who alluded to the controversy over Etihad. “I want to expand on preclearance capability. I want to expand on it in a way that does not give any airline or set of airlines a commercial advantage of any type,” he said.