Video showed Delta flight 89, a Boeing 777 bound for China, turning back to LAX Tuesday to make an emergency landing, and spewing fuel as it went in preparation for landing.

Unfortunately, that fuel ended up dousing children at Park Avenue Elementary in the city of Cudahy, CA.

Four teachers at the school have hired Gloria Allred to take on Delta. In the suit, obtained by TMZ, they say the pilot was asked by air traffic control if there was a need to dump fuel before landing ... and the pilot said no.

The suit alleges the pilot dumped the fuel without notifying the control tower ... and the big problem is ... it was done at an altitude of about 2,000 feet. According to docs, that's simply too low to allow the fuel to evaporate before it reaches the ground -- it should be done at 5,000 feet or higher.

In the suit, the teachers say their clothes, flesh and eyes were coated in jet fuel -- and it also got into their mouths. They say they had trouble breathing and needed medical treatment.