The tremendous influx of new overseas flights into Boston is producing bottlenecks at Logan Airport’s international terminal, with travelers increasingly facing waits to clear US Customs that can stretch to several hours.
The growing delays prompted the Massachusetts congressional delegation on Thursday to send a letter to the Department of Homeland Security complaining about “unacceptable” wait times and questioning why Logan has not received additional agents, as have other airports around the country.
At times the delay are so long, “international arrivals are being held on the tarmac where there is no capacity to offload passengers,” said the letter, signed by US senators Edward Markey and Elizabeth Warren and the nine Massachusetts House members. “These wait times are not just an inconvenience to travelers but also negatively affect economic activity in the region.”
Homeland Security did not respond to a request for comment. Customs and Border Protection declined to comment because it said it had not seen the letter from the Massachusetts delegation.
The Massachusetts Port Authority, which operates Logan, said the delays are occurring nearly every day during peak travel periods at the airport, between 3 and 9 p.m. The maximum waiting times for passport checks can run between 90 minutes and three hours, and travelers then face another 45 to 60 minutes to claim luggage and declare their items, the authority said.
On June 4, for example, some passengers from the six international flights that landed at Logan at about 6 p.m. waited as long as three hours to have their passports checked, according to data from the Customs and Border Protection website; the average waiting time for passengers that evening was about one hour.
Other airports are also experiencing long delays processing international travelers; the maximum wait times at one international terminal at John F. Kennedy airport in New York can be even worse than at Logan. But Customs data show that the backups in Boston during peak periods appear to be increasing in recent weeks.
Massport’s chief executive, Thomas Glynn, said that the recent delays represent a sharp turnabout for Logan, which previously was able to quickly move international passengers through its terminal.
“A year ago, our waits were one- third to one-half of the other larger airports. That has been one of our bragging points,” Glynn said. “We have a great reputation, and we want to fix this problem.”
Customs and Border Protection announced last year that it would add about 2,000 agents to its border posts around the nation, but Massport officials and the Massachusetts congressional delegation note that Logan has not received a single additional position.
The expansion of international air service has been a major boon for Logan, which now has nonstop service to 46 foreign destinations, including Shanghai, Hong Kong, Dubai, Istanbul, and beginning this weekend, Tel Aviv.
Nearly five million international passengers passed through Logan in 2014, up about 10 percent from the year before.
“What’s happening in Boston is that it’s becoming a victim of its own success,” said Henry Harteveldt, a travel industry analyst and the founder of Atmosphere Research Group in San Francisco.
“Massport has become so successful in attracting international carriers and convincing US airlines to add international flights that now Logan is groaning under the burden of serving these people.”
Harteveldt warned that the international service could suffer if Logan gets a bad reputation as a slow-moving gateway. He said that carriers will reduce the number of flights, run smaller planes, or stop flying in and out of Boston altogether.
“It’s a very tough situation,” Harteveldt said. “What’s especially frustrating is this is your real welcome moment to the United States — and it’s not at all a pleasant one.”
Last year, Customs and Border Protection introduced new kiosks for US citizens to automate the process of submitting declaration forms and biographical information and to reduce the clerical work placed on its agents. The 40 kiosks, which cost Massport about $3 million, are said to speed up processing times for Americans.
Once through the kiosks, US citizens then rejoin foreign travelers to wait to be processed by customs agents. Massport said the airport needs more agents to reduce the wait times at that stage.
Massport is in the midst of $30 million worth of improvements to the international terminal that include new jet bridges, updated holding areas and baggage screening facilities, and renovation of the immigration and customs area.
In its letter, the congressional delegation wrote that the improvements could be undermined by continued customs delays and requested Homeland Security to respond by July 16 with a plan to address the problems.
Taryn Luna can be reached
at taryn.luna@globe.com. Follow her on Twitter @TarynLuna.