Controlled explosions took place at schools in Corby and Kettering this week following national advice over the storage of chemicals.
The Explosive Ordnance Division attended Kingswood Secondary Academy on Monday (October 31) and Kettering Science Academy yesterday (Thursday).
The move followed advice given to schools across the country over the storage of 2,4 DNP (dinitrophenyl hydrazine), used in A-level chemistry classes.
Schools had been advised to check their stock and storage of the chemical by the Department for Education after fears it could explode if not stored correctly.
A spokesman for the Brooke Weston Trust, which runs KSA, said: “Following the recent nationwide alert from the National CBRN Centre regarding chemical 2,4 DNP (Dinitrophenyl hydrazine) Brooke Weston Trust can confirm that its secondary schools are assessing their chemical stocks of this item and, if necessary, following the recommended guidelines for its safe disposal.
“We can confirm that the Explosive Ordnance Division carried out a controlled explosion at Kettering Science Academy on November 3 in line with current advice and best practice.”
Kingswood Secondary Academy principal Andy Burton moved to reassure parents and residents.
He said: ““This is a national issue and the police have already worked with a number of schools and academies across the country to arrange for the disposal of this chemical.
“We contacted Northamptonshire Police after being advised by CLEAPSS that there was a low risk of it causing a small explosion or fire if it was dropped.
“We were advised not to release any information about the incident, in case it raised unnecessary alarm or concern.
“The whole operation was done in a safe and controlled environment when pupils had left the site.”
A Department for Education spokesman said: “We put out a reminder over the storage of 2,4 DNP which is used in chemistry at A-level to make sure it is done correctly.
“Some schools have come back after half term and gone to do a check and realised they have not been.”