Frontier Airlines said Thursday it will require passengers to have their temperatures taken before boarding flights, starting June 1, in an effort to make traveling safer during the coronavirus pandemic.

Anyone with a temperature of 100.4 or higher will not be allowed to fly, said the budget carrier said, which is among the airlines that serves Spokane International Aiport. While the move is a first for U.S. carriers, according to the airline, Air Canada announced a similar measure earlier this week. London’s Heathrow Airport is testing temperature screenings, an official there told the BBC this week.

“The health and safety of everyone flying Frontier is paramount and temperature screenings add an additional layer of protection for everyone on board,” Frontier Airlines CEO Barry Biffle said in a statement. “This new step during the boarding process, coupled with face coverings and elevated disinfection procedures, will serve to provide Frontier customers an assurance that their well-being is our foremost priority and we are taking every measure to help them travel comfortably and safely.”

Earlier this week, Southwest Airlines CEO Gary Kelly told CBS News that temperature checks should be put into place, but he said that should be the job of the Transportation Security Administration.

“We are urging the TSA to begin temperature scans as part of the screening process at the checkpoints,” Kelly said.

Frontier said in the statement that the screening should take place as passengers enter airports, and suggested the TSA and airports “may be working to lay that groundwork.”

In a statement, the agency said no decision about health screening measures at airports had been made.

“Ongoing discussions with our Department of Homeland Security and interagency colleagues, as well as our airport and airline partners, will enable the agency to make informed decisions with regard to the health and safety of the aviation environment,” the statement said. “The safety and security of the traveling public and our employees will always be our top priority.”

Under Frontier’s new policy, the airline will use contact-free thermometers before boarding. If someone’s temperature is 100.4 or higher, they will be allowed to rest before a second check, as long as there’s enough time before takeoff. If a secondary screening is still too high, the passenger won’t be allowed to fly. The announcement said Frontier would help the traveler rebook or “otherwise accommodate the traveler’s preferences with respect to their reservation.”

Frontier’s airport employees will not be allowed to work if their temperature is higher than the cutoff when their shift begins.

The announcement follows moves by airlines to require flight attendants and passengers to wear masks during flights.