Will TSA start allowing liquids? Not so fast, security experts say.

At a panel event in Washington last week, Homeland Security Secretary Kristi L. Noem said her agency is considering a change to airport security that would do away with a common passenger annoyance. If the Transportation Security Administration allowed travelers to carry on liquids of more than 3.4 ounces, fliers no longer would have to empty their water bottles or trash full-size containers of shampoo to clear a checkpoint.

“The liquids, I’m questioning,” Noem said during an interview at the conference hosted by politics website the Hill. “So that may be the next big announcement, is what size your liquids need to be.”

Noem was speaking just days after she announced that TSA was ending its “shoes-off” policy. But scanning liquids requires different technology than does inspecting travelers’ shoes. Some aviation security experts caution that the agency’s infrastructure might not be ready for such a move.

Noem has said that the Trump administration wants to usher in a new era of improved travel. From a security perspective, change does not appear imminent.

“I don’t think we’re at that point yet,” said Jeff Price, a professor of aviation management at Metropolitan State University of Denver.

“I was okay with the shoe-removal policy. That one seemed to make a lot of sense from a technological perspective,” Price said. “But these changes seem to be happening so rapidly. I think they need to pump the brakes just a little bit.”

To screen liquids, TSA requires some of the most sophisticated technology available in the security industry. The agency has been installing computed tomography (CT) scanners at a steady rate, but not fast enough to handle an abrupt change in policy.

Neither the Department of Homeland Security nor TSA answered questions about when the changes could occur, what a revision of the 19-year-old rule would entail, and whether the rollout would be nationwide or only at airports with the most advanced technology.

“Secretary Noem and TSA are constantly looking for ways to enhance security and improve the travel experience for the public,” read a statement that Homeland Security sent to The Washington Post. “Any announcements on policy changes will be made through official channels.”

Secretary of Homeland Security Kristi L. Noem, speaking during a news conference at Reagan National Airport this month, says she is questioning the amount of liquids fliers are permitted to carry on to a flight.

Gaps in technology

TSA has been loosening security measures drafted in the early 2000s, thanks to leaps in technology and intelligence methods. At hundreds of airports, passengers in standard lanes no longer have to remove electronics and liquids from their carry-on bags. Boarding passes can stay in pockets and purses. Shoes remain on.

For a change of this magnitude, analysts say one of two events must take place. The country must see large-scale advancements in scanning technology or a decline in threats against air travel safety.

Whether an airport is ready for your travel mug of coffee or jug of sunscreen depends on the type of scanning equipment it operates. The superstar of scanners, at least for now, is the computed tomography machine.

Since 2018, TSA has been investing billions of dollars in CT scanners, one of the most advanced pieces of equipment to grace security checkpoints. (The medical field uses the same technology to peek inside patients’ bodies.) Price said CT scanners, which generate three-dimensional images that TSA officers can inspect from different angles, are a welcome replacement. Older X-ray machines, he said, cannot reliably discern between harmless and harmful liquids.

Though the CT scanner is superior to earlier models, hundreds of airports are still waiting for the technology. As of June 30, TSA said it has installed more than 1,016 units in 278 airports, a sliver of the more than 5,000 public airports in the country, according to the Federal Aviation Administration. Price said deployment to a majority of airports could stretch until 2042, but he doesn’t anticipate it will take that long.

“There’s still a gap,” Price said, “and it could be another 10 years before that gap is filled.”

Aviation security analysts and advisers say they trust the technology, but they admit that no machine is infallible.

“Is it advanced enough at this point in time?” said Mike Evans, director of the Risk Intelligence Center at security firm Securitas. “That’s always going to be the case with any kind of technology. There’s always that hedge-your-bet approach to it.”

The United States has avoided aviation-based terrorist attacks on the scale of Sept. 11, 2001, Price said, but sometimes at the expense of convenience.

“The golden age of travel was wonderful for passenger convenience, but there was also a lot more safety incidents and accidents and a lot more security incidents, hijackings and bombings,” he said. “Travel now might not be nearly as fun, but we’re a lot safer.”

Evans said the relative calm over the years is proof that TSA’s measures are working. The protocols have “lowered the risk to an acceptable level,” he said, and authorities can take steps to refine the screening process.

However, before DHS ditches one of the bastions from the aughts, all of the essential elements — the technology, the trained employees — must be in place. According to security analysts, they aren’t.

Since 2019, the TSA has been acquiring and deploying computed tomography (CT) scanners, which allow passengers to leave their electronics and quart-sized bag of liquids in their carry-on bags. Dulles International Airport is one of about 100 airports employing the newer technology. (Andrea Sachs/The Washington Post)

Extra task for TSA officers

Since the start of the new administration, the White House and Congress have been picking away at TSA, reducing its workforce and eliminating its negotiating power.

In February, the DHS fired more than 200 TSA employees. The following month, the agency terminated collective bargaining for TSA security officers, saying in a news release that the union-backed practice was hindering its primary mission “to safeguard our transportation systems and keep Americans safe.” Sen. Mike Lee (R-Utah) has repeatedly called for the dissolution of the agency.

Caleb Harmon-Marshall, a former TSA employee who broke the news about DHS ending the shoes rule, said the department probably will wait until more airports are equipped with CT scanners to allow passengers to travel with regular-size liquids. He gives it two years. He also said TSA has bottle scanners, which its officers can use as supplemental security.

“The implementation may cause fatigue with the officers,” said Harmon-Marshall, who covers security issues in his Gate Access newsletter. “The tech is there, but you still need a live human to check these bags containing these larger size liquids.”

The United Kingdom has been trying to relax its liquid restrictions for years.

In 2019, Prime Minister Boris Johnson vowed the return of standard-size liquids by 2022. The deadline was pushed back to 2024 because not all of the airports were prepared. In June 2024, some airports started allowing up to two liters of liquids. Then the Department for Transport reversed its decision. This month, two airports — Birmingham and Edinburgh, neither the biggest nor the busiest hubs in the U.K. — introduced the more lenient measures.

On its website, Edinburgh Airport explained the revised policy. Passengers can carry up to two liters in multiple containers and leave them in their carry-on bags during the screening process. However, “not all airports will have the same equipment or capability.” This includes London Heathrow, which handled a record 83.9 million passengers last year, according to the Heathrow Media Center.

“It depends on what’s installed in what lane and who is on shift that day,” Evans said of Europe’s busiest airport. “Imagine that scaled across 50 states in the U.S.”

Expect disruptions

Rich Davis, a senior adviser with security assessment firm International SOS and a former chief security officer with United Airlines, trusts the government is acting scrupulously.

“I really don’t believe the secretary would bring it up unless there was a very good confidence level,” Davis said.

Even so, he said travelers should not expect a uniform rollout because of the technology disparities among U.S. airports. He said people should be prepared for a disjointed experience, depending on their point of departure.

“Nothing can happen uniformly overnight for the size of our country,” Davis said. “Something that’s available in Atlanta might not be available in Reno, Nevada, for instance, and that will cause a little bit of a disruption.”

Davis said officer training, including educating passengers, can help iron out the bumps. It might not be initially smooth, however, with security-lane slowdowns or slight confusions.

One way to keep the line moving is to continue traveling with tiny toiletries.

“Even if they change the rules, I don’t know if I’ll change my habits,” Davis said. “Everything has worked well for 19 years.”