Long and occasionally chaotic security lines tested the patience of travelers Monday at the Minneapolis-St. Paul International Airport’s main terminal — and could do so for months.

The lines at Terminal 1, also known as the Lindbergh terminal, are the result of a construction project at the south checkpoint, limiting the number of people being screened there. Monday was the first test of the new configuration, which will last until mid-December.

“I’ve never seen anything like this,” said a frazzled Melanie West, of Raleigh, N.C. She had about 40 minutes to catch her flight, and wasn’t close to the north checkpoint entrance.

Lines for the south checkpoint, reserved for those with TSA PreCheck, Clear with PreCheck and airport employees, were often longer than those for passengers without expedited screening using the north checkpoint. This caused some consternation — PreCheck costs $85 for five years, and Clear, $179 a year.

More challenges lie ahead — the temporary system will be in place for teacher conferences in October and Thanksgiving, both busy travel times.

The checkpoint project is part of a multiyear $1.6 billion renovation that calls for a redo of the ticketing lobby and other areas. Parts have been walled outside security for construction, including new elevators, a coffee shop and restrooms, causing a pinch point at the terminal’s midsection.

“This is the worst I’ve ever seen it since Super Bowl Monday,” said Sean Stapleton, a tech executive from Carver referring to the day-after the Super Bowl, the busiest in MSP’s history.

“It’s not like I’m some rookie traveler,” said Stapleton, who flies 250,000 to 300,000 miles a year.

Stapleton and his friend, Mike Donovan, were flying to a conference in Las Vegas. “I’ve been running back and forth to see if the first class line is faster, but now I’m committed to this line,” said Donovan, of Chaska. “At least I got my steps in.”

Monday mornings are usually busy in Terminal 1, as business travelers take to the skies.

Metropolitan Airports Commission (MAC) spokesman John Welbes said wait times between 5 a.m. and 6 a.m., a usually busy period, were under a half-hour for most passengers Monday. The lines tended to ebb and flow throughout the morning.

Cliff Van Leuven, TSA’s federal security director for MSP, told MAC members that 41,400 people were screened Monday, not a particularly high number, and the average wait time was about 33 minutes. On Thursday, up to 46,000 people are expected to be screened, he said. One problem Monday morning was that an X-ray machine at the south checkpoint was not working, so not all six lanes were open, he said.

“We learned a lot of lessons this morning that will serve us better” in the future, van Leuven said.

The MAC used staff, contractors and volunteers on Monday to direct harried travelers to appropriate checkpoints, some brandishing glowing red lights to show the way. Adding to the confusion were yellow-vested construction workers moving about the terminal. Lines to check bags for Delta Air Lines flights swelled on occasion, as well.

Brian Cantrall, of Phoenix, purposely arrived at the airport nearly four hours ahead of time for his flight home. “I saw it on the news. They made it sound like Armageddon,” he said.

Some vented on social media. Twin Cities chef, restaurateur and TV personality Andrew Zimmern tweeted that the lines were “literally the worst I’ve ever seen since the airport was built. I’m on at least 2 flight(s) a week here and NEVER seen it like this. #lordoftheflies.” Fox Sports personality Jay Glazer called the scene “unreal” in a tweet.

A spokesman for Delta, the dominant carrier at the airport, said the airline “elected to briefly delay a limited number of flights due to extended security screening times at MSP’s Terminal 1 as a result of airport construction.”

On Sunday, U.S. Sen. Amy Klobuchar called on the TSA to increase staffing at MSP, saying that between 2012 and 2017 passenger traffic at the airport increased 12% while the number of TSA screeners was cut by 9%.

“It is critical that officials do everything possible to mitigate the impact on wait times caused by this construction, particularly as MSP has seen the numbers of passengers at the airport increase,” Klobuchar said in a news release.

Celia Hahn, president of the American Federation of Government Employees Local 899, which represents TSA screeners at MSP, said officers are being forced to work overtime, partly because about 60 officers are in training.

Hahn said TSA staffers are “stressed and tired,” and there’s a shortage of female officers. Recruiting women is especially hard “because this is not a family-friendly place to work,” she added. “It’s difficult to find day care at 3 a.m. on the weekends.”

Another checkpoint available to ameliorate the wait for travelers with carry-on luggage is located on the third floor of the Intercontinental MSP Airport Hotel, which opened in 2018. The checkpoint, connected to Concourse C by skyway, is open from 5:15 a.m. to 10 a.m. daily. Passengers may be dropped off at the entrance of the hotel, park in the ramp next to it, or take the Intercontinental shuttle from the terminal to the hotel.

A different skyway security checkpoint on the connector bridge between concourses C and G is temporarily closed, due to TSA staffing limitations, according to the MAC.