An RAF bomb disposal unit carried out a controlled explosion on a powder chemical stored at University Academy Holbeach.
The visit last Wednesday (November 2) at 2pm followed a nationwide notification two days earlier by Consortium of Local Education Authorities for the Provision of Science Services (CLEAPSS) about a risk if the chemical – known as 2,4-DNP – is not stored correctly.
Academy principal Steve Baragwanath said a small hole was dug in a school field for the operation, which created a minor bang.
Although there was no risk to staff or pupils, he had asked if the operation could be carried out after school hours.
The chemical was only used in experiments a couple of times a year.