It occurred when a rack holding four litres of a mix of chemical substances collapsed at 1.10pm, The Star Online reported.

Among the chemicals were phosphorous and lithium, which are highly combustible.

School authorities however were quick to take action and immediately contacted the Fire and Rescue Department which sent its hazardous material (Hazmat) team to the scene.

The report said lithium was classified as a liquid explosive and Hazmat personnel had to stabilise the substance by allowing it to burn off.

They also neutralised the other chemicals.

No injuries were reported.