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Frontier Airlines will begin temperature screening all passengers and crew members next month, becoming the first US carrier to announce such a safety measure.

The airline said Thursday that the screening regimen with a touchless thermometer will start June 1 and “anyone with a temperature exceeding 100.4 degrees Fahrenheit will be denied boarding.”

Passengers who test above that limit “will be given time to rest,” and if a second screening is also high, “a Frontier gate agent will explain to the customer that they will not be flying that day for the health and safety of others.”

Tests will be conducted at the boarding gate by the agent.

CEO Barry Biffle said the temperature screenings are “an additional layer of protection for everyone onboard.” The airline is one of several U.S. carriers to require all passengers and crew to wear face masks.

On Thursday morning, Frontier said it is no longer charging customers $39 or more to reserve an empty neighboring seat as part of a social distancing initiative. The change came after lawmakers blasted the plan as “unreasonable.” Frontier said it will continue to block seats but not charge customers.

Airlines for America, the industry’s trade group, suggested that either the TSA or some other government agency should conduct temperature checks as part of regular airport screening, rather than having individual airlines conduct the tests. That view was echoed Friday morning by Joanna Geraghty, president of JetBlue Airways, in an interview on CNN’s New Day.

“We want people flying that are healthy,” Geraghty said. “There are questions around whether temperature checks can actually identify whether an asymptomatic person has a coronavirus. Temperature checks are good just to ascertain whether somebody has an illness, and potentially shouldn’t be flying. Our perspective is there needs to be a global industry standard for this. Different standards for different airlines is going to be challenging for the traveling public. Our recommendation is for the government to step in.”

She said that based on discussions with the FAA and TSA, there could be more changes in the next few weeks.

“This is an evolving conversation,” she said.

Southwest Airlines (LUV) CEO Gary Kelly told CNN on Wednesday that the airline is “urging the TSA” to take travelers’ temperatures.

“At this time, no decision has been made regarding specific health screening measures at airports,” the agency said in a statement Friday.

The TSA said it is relying on health expertise for guidance and confirmed that it’s in “ongoing discussions” with the airlines.

CNN Business’ Chris Isidore and Jackie Wattles contributed