Delta Air Lines spent more than $10 million on sanitization and cleaning measures in response to the coronavirus.

The measures include electrostatic spraying to sanitize planes and expenditures on personnel, supplies and equipment, according to Delta’s chief customer experience officer Bill Lentsch. The airline now has 1,600 sprayers to sanitize planes before each flight, he said.

Delta is also among the airlines requiring employees and passengers to wear masks. Airlines have said those who do not comply may lose their future flight privileges on that airline.

Delta has banned more than 100 passengers who refused to wear masks.

“If you board the plane and you insist on not wearing your mask, we will insist that you don’t fly Delta into the future,” said CEO Ed Bastian said on the Today Show on Wednesday.

“It’s few and far between that you run into problems,” said Delta flight attendant Herdley Harrison. If there are passengers who don’t wear a mask, he asks them repeatedly to wear one, and it usually works the third or fourth time.

If a passenger refuses and does not qualify for a medical exemption, the customer is referred to a Delta conflict resolution officer.

Delta is also blocking middle seats until Sept. 30, and for some period beyond that.

The airline has rolled out its new policies while losing billions of dollars and slashing its workforce through buyouts and early retirements, as most travelers stay home due to the COVID-19 pandemic.

Airlines are touting safety practices as people weigh whether it is safe to fly. Delta says many of the new measures will be permanent.

In between flights, Delta employees or contractors pull open overhead bins and tray tables, spray a disinfectant throughout the cabin, then wipe down surfaces to clean them.

The process takes anywhere from about 40 minutes to a little over an hour, depending on the size of the plane, said Azeem Mistry, Delta’s director of airport operations.

Since flight schedules had at least 40-45 minutes between flights, it takes some extra time, but not much, according to Mistry.

He said the company is also considering other measures such as UV lights to sanitize surfaces or some other type of continuous cleaning mechanism throughout the flight.

“We’re looking at ways where we can maintain the same level of clean that you get at boarding throughout the flight,” Mistry said. “That’s the next step.”

Josh Smith, Delta’s manager of environmental health and industrial hygiene, said most of Delta’s planes already have HEPA filtration systems that clean air every 2-3 minutes, with air circulating vertically between vents overhead and in the floor of the cabin. Other planes in Delta’s fleet without HEPA filtration draw in outside air, he said.