More than two dozen passengers were released from the hospital after a deadly runway crash at the LaGuardia Airport.

U.S. investigators are decoding the black box from an Air Canada Express plane that collided with a fire truck shortly after landing at New York’s LaGuardia Airport to determine what caused the first deadly accident at the airport in more than 30 years.

The cockpit voice recorder and data recorder have been recovered and sent to Washington DC, said Jennifer Homendy, chair of the National Safety Transportation Board, during a news conference Monday evening.

“At this point in the investigation, we have questions on everything,” she said.

The captain and co-pilot died in the collision that occurred at about 11:40 p.m., the Port Authority of New York and New Jersey said early Monday. More than 43 people were transported to the hospital and many have been released, Kathryn Garcia, executive director of the Port Authority of New York and New Jersey, told reporters in a briefing Monday afternoon.

The airport reopened at 2 p.m. local time, although the Port Authority warned travelers to expect residual delays and cancellations.

The plane, which took off from Montreal, was carrying 72 passengers and four crew, Jazz Aviation LP, which was operating the flight, said in a statement. The aircraft hit a Port Authority fire truck shortly after touching down and came to a standstill about halfway down the runway.

Homendy said the runway where the collision occurred will be closed for “some time.”

“It’s been a real challenge to get the entire team here, and they’re still arriving as I speak,” she said during the brief news conference, referring to long airport security lines amid a partial U.S. government shutdown. NTSB has completed a walking inspection of the crash scene, she said, and would provide more information about the crash on Tuesday.

Photos from the scene showed the front section of the plane, including the cockpit, sheared off, with debris dangling from the nose section. A demolished yellow rig lay behind the plane.

A recording of the air traffic control communication at the time of the LaGuardia incident shows “Truck 1 and company” requested to cross runway 4, which was where the Air Canada jet was due to land. The truck was responding to an emergency declared minutes earlier by a United Airlines Holdings Inc. flight, which reported a sickly smell in the cabin.

A subsequent unidentified voice, likely an air traffic controller, told Truck 1 to “cross 4 at delta.” Subsequently, the unidentified voice said “stop, stop, stop, stop Truck 1, stop, stop stop. Stop Truck 1.”

The unidentified controller then said to the pilots: “I see you collided with a vehicle there. Just hold position. I know you can’t move. Vehicles responding to you now.”

Homendy said a controller involved in such an incident would typically “be removed from duty.”

“Certainly it’s pretty traumatic for that air traffic controller,” she said. “And we’ll want to interview that air traffic controller as well as others that were in the tower, maybe not even in the tower.”