The number of airport security workers failing to show up for work hit an all-time high over the weekend, straining checkpoint lanes at several major hub airports.

The number of unscheduled absences was 8 percent nationally, compared with 3 percent a year ago, as the Transportation Security Administration conceded that many of its workers could no longer handle the financial hardship of working without pay during the partial government shutdown. The agency said the stress was being felt at checkpoint lanes in New York, Atlanta, Chicago and Miami.

At Baltimore-Washington International Marshall Airport, one checkpoint was shut down at 5:35 p.m. Saturday because of a shortage of workers. At various points during the shutdown, airports in Atlanta, Houston and Miami also have operated under contingency plans to address the shortage.

“There is an increasing percentage of the TSA workforce that is calling out predominantly for financial reason,” said TSA spokesman Michael Bilello. “This is isolated now to a number of our largest hub airports.”

Bilello said the agency had sent special agents from its National Deployment Force to supplement checkpoint agents. NDF members normally are dispatched when there’s an event like the Super Bowl or a crisis like a major hurricane.

“We have fully deployed our established NDF and (are) increasing its size substantially,” Bilello said, “but TSA’s capability is still limited and will ultimately lead to increased lane closures in order to maintain security effectiveness.”

Bilello said NDF officers have been deployed to airports across the system, including Atlanta, Newark and LaGuardia.

TSA agents are among the estimated 800,000 federal employees who are furloughed or working without pay during the shutdown, which is entering its fifth week.

Brent D. Bowen, a professor of aviation at Embry-Riddle Aeronautical University’s Arizona campus, said the demand for TSA workers to continue work without pay would have an inevitable impact. “We can’t expect any group of people to work indefinitely for no pay,” Bowen said. “It affects morale, they’re worried about their families. When that happens you can’t focus on your job as well as you would under normal circumstances.”

Rolland Vincent, an industry expert and co-chair of an aviation group under the National Academies of Sciences, Engineering, and Medicine, said TSA agents have a vital job to do, and their work, along with that of the Federal Aviation Administration, is being recklessly undercut by the shutdown.

The nation, Vincent said, “is playing with guns.”

“We’re exposed,” added Vincent, co-chair of the Transportation Research Board’s subcommittee on commercial aviation. “Somebody is going to et hurt.”

Despite the record number of no-shows among TSA checkpoint agents Saturday, the TSA said virtually all of the 1.6 million passengers screened passed through within the agency’s 30-minute standard, and that almost 94 percent cleared through in 15 minutes or less.