The Federal Aviation Administration said planes were supposed to release fuel over “designated unpopulated areas, typically at higher altitudes so the fuel atomizes and disperses before it reaches the ground.” The agency said it was investigating the dump.

Adrian Gee, the spokeswoman for Delta, said the flight had dropped the fuel “to reach a safe landing weight.” She said airline officials “share concerns regarding reported minor injuries to adults and children.”

Many jetliners, especially those used on long flights, carry so much fuel when fully loaded that they take off weighing more than their maximum safe landing weight. Ordinarily, they consume enough fuel along the way to be well below the maximum threshold by the time they land. However, if a flight is cut short soon after takeoff, the plane may still be significantly overweight.

In that situation, pilots have three choices. They can circle for a while to burn off fuel, but in an emergency there may not be time. They can land overweight, which risks damaging the aircraft. Or they can jettison fuel in flight, generally by spraying it out through nozzles on the plane’s wings, if the plane is equipped.