A Transportation Security Administration employee works at a security checkpoint at Miami International Airport Friday in Miami. Credit: Lynne Sladky | AP

The number of Transportation Security Administration security airport workers who did not show up for duty Sunday reached a record 10 percent of the checkpoint workforce, leading to growing lines in several places, with the longest in Minneapolis and New Orleans.

The union that represents the TSA workers, the American Federation of Government Employees, has warned since the federal shutdown began that its employees are among the lowest salaried on the federal pay scale and simply may be unable to make the commute to airports if stranded without a paycheck.

“The fact of asking, or in fact demanding, that people continue to come to work and not receive something and have no idea whether they even will receive back pay in many cases is an absolute killer for morale,” said Erin E. Bowen, a psychology professor at Embry-Riddle Aeronautical University’s Arizona campus. “Any time you have these situations where people feel like they have no control over their work environment and no control over whether their effort receives payment, you’re going to see really wide-ranging consequences, and some of them are going to be bordering public safety concerns.”

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.

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

The absentee rate one year ago — Jan. 20, 2018 — was 3.1 percent, the TSA said.

In addition to a 35-minute wait at Minneapolis and a 45-minute wait in New Orleans (which hosted an NFL playoff game Sunday), the most busy 40 airports showed the strain of processing passengers while 1 in 10 workers were off the job. Fourteen airports had checkpoint waiting times of more than 20 minutes, with three of them pushing the maximum TSA acceptable wait time of 30 minutes. In Los Angeles (29 minutes), Tampa (28) and Chicago (27), the lines were extensive.

One of three TSA checkpoints at Baltimore-Washington International Marshall Airport was shut down twice over the weekend, but the TSA said Monday that it was operational again.

Overall, the TSA said that it screened 1.78 million passengers Sunday. They said that more than 93 percent of them waited for 15 minutes or less.