First responders have revealed the likely reason a science experiment at a Sydney school ended in an explosion and led to a 10-year-old girl being flown to hospital with severe burns.

Eight ambulances and two helicopters, one with a specialist medical team on board, rushed to the incident at Manly West Public School in Balgowlah at about 1pm on Monday.

11 children around the age of 10 and one adult were impacted by the “Hazmat incident”, reportedly caused by a science experiment gone wrong.

Wellbeing support was offered to students. Photo / NCA NewsWire / Dylan Coker

It’s understood the incident occurred during a “black worm” experiment, which involves using an accelerant to set baking soda and sugar alight.

New South Wales Ambulance said Monday’s high winds were partially to blame for the Year 5 class’ experiment going wrong.

“We received multiple triple-zero calls reporting that a number of children had sustained burns during a science experiment, which was being conducted outside,” NSW Ambulance Acting Superintendent Phil Templeman said.

Police and Safe Work NSW staff near an empty bottle of flammable liquid at the scene. Photo / NCA NewsWire / Dylan Coker

“Today’s high winds have impacted the experiment and blown some of the materials around.”

The most seriously injured child, a young girl, suffered multiple burns to her body and was flown to The Children’s Hospital at Westmead in a stable condition after receiving treatment from CareFlight’s specialist doctor and a NSW Ambulance critical care paramedic.