LOS ANGELES－An airplane with engine trouble returning to Los Angeles International Airport, or LAX, on Tuesday morning dropped jet fuel onto five schools, leaving some people with minor injuries.

The fuel, described by fire officials as a vapor, caused minor skin and lung irritation to 56 children and adults but nobody was taken to the hospital and the only decontamination required was soap and water, officials said.

The airplane, Delta Flight 89, had taken off with 149 passengers on board and was en route to Shanghai when it turned around and headed back to the airport, according to the Los Angeles Times.

"Shortly after takeoff, Flight 89 from LAX to Shanghai experienced an engine issue requiring the aircraft to return to LAX," Delta spokesman Adrian Gee said. "The aircraft landed safely after an emergency fuel release to reduce landing weight."

The mist fell on five elementary schools, but all injuries were minor and there weren't any evacuations, Los Angeles County Fire Department Inspector Sky Cornell said.

"That's a great sign," Cornell said.

All the fuel evaporated very quickly and nothing flammable remained in the air or on the ground, he said.

Diego Martinez, a sixth-grader at Park Avenue Elementary in Cuday, said he and his classmates were outside for physical education class when they saw the airplane flying low overhead.

"It was very close," he said.

The FlightAware website's flight track showed the jet took off over the ocean and made an immediate right turn toward land and circled back over Southern California to approach the airport from the east.

The Federal Aviation Administration said it is investigating.

"There are special fuel-dumping procedures for aircraft operating into and out of any major US airport," the FAA said in a statement. "These procedures call for fuel to be dumped over designated unpopulated areas, typically at higher altitudes so the fuel atomizes and disperses before it reaches the ground."