A Delta Air Lines flight out of Las Vegas was canceled Monday after several passengers and at least one crew member fell ill amid “uncomfortable temperatures” on the plane as they waited for it to take off during an unrelenting heatwave, the airline said.

Multiple customers on Flight 555, which had been bound for Atlanta from Harry Reid International Airport, were seen by first responders, including a passenger and a flight attendant who had to be transported to a local hospital, according to Delta.