The army has revealed it carried out a controlled explosion on a 'device' in Derbyshire.
At 3.25pm yesterday, Matlock firefighters were called to a factory in Darley Dale.
A Derbyshire Fire and Rescue Service (DFRS) spokesperson said a 'potentially volatile material' had been found.
One hundred workers were safely moved from the site and the A6 was closed for a period of time.
Shortly before 8.30pm yesterday, DFRS said a controlled explosion had 'successfully taken place'.
Station manager Dean Gazzard, of DFRS, said firefighters worked with the army bomb disposal unit, Derbyshire Constabulary and Derbyshire County Council's emergency planning team to bring the incident to a 'safe conclusion'.
He added: "I would like to reassure the public that there is no risk to residents living in the area, nor anyone travelling close to the scene.
"Working with our partners, safety cordons were put in place to ensure the safety of all local residents."
An army spokesperson said: "An army explosive ordnance disposal team supported emergency services in Derbyshire with the disposal of a device."
A Derbyshire Constabulary spokesperson said no arrests have been made.
A council spokesperson said its emergency planning team provided sandbags which were used by the army bomb squad as it carried out its work.
According to the Derby Telegraph, it is believed the business at the centre of the incident was an aero engine factory.
Arconic Engines in Dale Road North is a 'world-class producer of aero engine and industrial gas turbine components', according to its website.
The Derbyshire Times asked Arconic Engines for a comment this morning but had not received one at the time of publication.
Residents are advised not to be alarmed.
No further information is available.