Thomas Adams School criticised for blowing up chemicals Published duration 1 November 2016

media caption The blast was supervised by police and bomb disposal experts

A school that blew up old chemicals on its playing field has been criticised for not providing a public warning of the blast.

Residents in Wem, Shropshire, were alarmed when The Thomas Adams School carried out the explosion on Monday while children were trick or treating.

The 19:30 GMT blast was supervised by police and bomb disposal experts.

Head teacher Liz Dakin apologised for "distress" caused, but said the school had followed police advice.

Police said they had also supervised two similar controlled explosions at schools in Redditch and Evesham in Worcestershire, also on Monday.

The De Montfort School in Evesham said a controlled explosion had taken place after the end of the school day and there was "no ongoing risk to students or staff".

In Wem, residents complained on the Lowe Hill school's Facebook page about the lack of advance warning.

media caption Neighbours have been talking about the explosion at a Wem school last night

One said the noise was "immense" and "worrying", especially when families were out celebrating Halloween.

Mrs Dakin said the school was acting in response to advice from Government advisory science service CLEAPSS to check for the chemical 2,4-DNPH - sometimes used in chemistry lessons.

What is 2,4-DNPH?

2,4-dinitrophenylhydrazine is used in chemistry lessons and is perfectly safe if stored correctly

A-level syllabus, where 2,4-DNPH was used in organic chemistry, has changed

Action needs to be taken if there is evidence it has dried out because it could cause burns

Destroying it with an explosion is one option

CLEAPSS said the situation has arisen in a number of schools across the country - the organisation would not be drawn on how many

CLEAPSS said the action taken in Wem was proportionate

If not stored properly the substance can cause serious harm.

Police were in attendance for its disposal, but Mrs Dakin said: "We also were not aware of how big the bang would actually be.

"We do apologise to the public for any distress caused but, of course, we were following police instructions."

image copyright Google Maps image caption The Thomas Adams School in Wem had been advised to get rid of certain chemicals

She added police had told her their time is being taken up by doing the same thing at schools across the country.

The school was open as usual on Tuesday.

West Mercia Police said officers assisted an explosive ordinance disposal unit who conducted a controlled explosion on some chemicals.

Safer Neighbourhood Inspector Nigel Morgan said: "The chemicals were safely dealt with by the EOD unit on the school playing field at around 8pm last night and although local residents may have experienced a loud bang, all relevant steps were taken to ensure that the local community were kept safe from harm".