The Transportation Security Administration would do temperature checks of travelers at U.S. airports for signs of fever under new legislation introduced Friday.

The bill, sponsored by Sen. Maria Cantwell (D-Wash.) and Sen. Rick Scott (R-Fla.), would require the TSA to set up a 120-day pilot program. Data collected from the pilot project would be used to expand the program to additional airports. Legislation to create a similar program was introduced in the House in July.

“Americans deserve all the available tools to fight COVID-19,” Cantwell said in a news release announcing the legislation, referring to the disease caused by the novel coronavirus. “For workers and the traveling public, a temperature check program provides important data. The legislation I introduced would require TSA to use innovative temperature screening technology to better protect passenger and worker health, and build public trust in the aviation system.”

For months, U.S. airlines have called on the TSA to conduct temperatures scans, saying such a measure would help build passenger confidence in air travel at a time when many are reluctant to fly because of concerns about the pandemic. But the agency has been reluctant to take on the task, saying that it’s not clear the scans would be an effective strategy for identifying those with the coronavirus. Some people may have the virus but not a fever, and some may have elevated temperatures but may not be infected with the virus, the agency says.

The Trump administration recently ended enhanced screening for travelers from a number of countries, including China and more than two dozen European nations. In announcing the decision, officials noted that the Centers for Disease Control and Prevention found that the screenings, which included temperature checks, showed “limited effectiveness” at catching sick people.

“We now have a better understanding of COVID-19 transmission that indicates symptom-based screening has limited effectiveness because people with COVID-19 may have no symptoms or fever at the time of screening, or only mild symptoms,” the agency said in a statement.

A CDC spokeswoman said 675,000 people underwent the screenings and fewer than 15 were identified as having covid-19.

Even so, a handful of airports in Hawaii, California, New Jersey and Washington state have begun doing temperature checks. Frontier Airlines also requires passengers to have their temperatures taken before they board their flights. Despite doubts about their effectiveness, the checks are popular with travelers. A recent survey by the International Air Transport Association found that 80 percent of travelers said temperature checks made them feel safer when traveling.

Under the legislation, the TSA would have 30 days to establish a pilot program at airports that “represent diverse operating” conditions. Data collected from the 120-day pilot, including the most effective technology for conducting the scans, would be used to expand the program, which would be in place until the end of the coronavirus emergency.

In addition, TSA officials would be required to develop policies that ensure the privacy of travelers’ personal and medical information, address how to deal with people who may have a fever unrelated to the coronavirus, and accommodate individuals with disabilities or who observe certain religious practices.

The measure would allow passengers who are barred from flying to cancel or change their flight at no cost to them.

“In addition to passengers, staff and other airport visitors self-screening and staying home if any symptoms develop, temperature checks could provide an added layer of defense against transmission in the air travel system,” said Chris Spitters, health officer for Snohomish Health District in Washington state. “It may not catch every case of covid boarding aircrafts, but it does add some additional protection above and beyond the existing strategies for maintaining passenger and crew safety with respect to covid.”