Dozens of passengers onboard became violently ill.
"Battalion 3, at this time we have a Frontier Airlines coming in with 253 souls onboard, numerous patients feeling nausea, vomiting," a member of the El Paso Fire Department is heard saying in an audio recording. "Also, we might want to make this a hazmat, again not knowing what's causing the illness."
Another fire official is heard saying: "This might be carbon monoxide. We have our monitors uploading."
Multiple passengers were treated for the potential carbon-monoxide poisoning. Some who were onboard the flight said it was initially delayed in Las Vegas as maintenance crews worked to repair a fuel line.