Los Angeles County firefighters and paramedics responded to an elementary school in Cudahy, California, after children came into contact with jet fuel dumped by a plane flying overhead.

Seventeen children and nine adults were hit by the fuel and complained of minor injuries, the LA County Fire Department told Business Insider. The department's Health Haz Mat units responded and confirmed that the substance was jet fuel.

ABC 7 Los Angeles reported that the victims were complaining of skin irritation.

Two classes were outside in the school's playground when the liquid "rained down" just before noon, the Los Angeles Times reported.

It was not immediately clear which flight dumped the fuel, nor the reason. Jettisoning fuel to reduce weight is a common practice when a jet is forced to return to the airport after take-off, often due to a technical issue or passenger medical emergency.

Typically, jet fuel dissipates when it's jettisoned from a plane. It was not immediately clear why the fuel ended up reaching the ground in this instance.

Delta flight 89 from LAX to Shanghai, China, returned to the airport shortly after taking off at around the same time, according to data from FlightRadar24. The plane, a Boeing 777-200, passed 2,375 feet over the Cudahy area at 11:53 a.m.

Video posted to Twitter purported to show the plane dumping fuel on approach, but could not be independently verified by Business Insider.

Delta did not immediately return a request for comment.

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