A scary accident at Chicago O’Hare International Airport left a worker in critical condition after a plane and a towing vehicle collided Saturday evening. The incident happened around 7:35 p.m. when an Air Wisconsin jet, approaching its gate, struck the tug—a vehicle used to move aircraft—causing it to flip over and trap the driver underneath.

The 64-year-old tug operator, who works for United Airlines, suffered serious head and lower-body injuries. Emergency crews rushed him to Advocate Lutheran General Hospital, where he was stabilized. United Airlines said they’re making sure he gets the care and support he needs.

The Air Wisconsin plane, a Bombardier CRJ-200, had just landed from Kalamazoo-Battle Creek International Airport in Michigan. Thankfully, all passengers exited safely and were taken to the terminal without injury.

Despite the incident, operations at O’Hare continued smoothly, according to the Chicago Department of Aviation. The Federal Aviation Administration and Chicago Police are investigating what caused the crash.

This accident comes just a day after a tragic plane crash in Northeast Philadelphia, which claimed six lives on board and one person on the ground. It’s a sobering reminder of the risks in aviation, even on the ground. More updates are expected as the investigation unfolds.