A CONTROLLED explosion has taken place at a Hereford industrial estate this afternoon after the discovery of suspected phosphorus grenades.

Explosive Ordnance Device experts carried out a controlled detonation at Rotherwas Industrial Estate. 

The 200m cordon placed around the estate has been reduced to 50m so local residents and businesses, evacuated yesterday evening, can now return to their properties.

A 'crate' of devices has been located, containing 24 grenades. They have been carefully extracted and detonated.

They are believed to be self-igniting phosphorus (SIP) grenades. They are not explosive devices but glass jars with a combustible compound.

Dr Naveed Syed from Public Health England (PHE) West Midlands Health Protection Team said: "Any smoke emanating from the controlled detonation of the material should disperse quickly into the atmosphere, minimising exposure to the public. However residents are advised to shelter, close all windows and doors, and to keep away from the smoke to minimise any potential exposure.

"Smoke may contain substances that can irritate the lining of the air passages, eyes and the skin. Respiratory symptoms can include coughing and wheezing, breathlessness, sputum (phlegm) production and chest pain. Any health effects are likely to be very short-lived and probably due to the irritant effects of the smoke.

"People with asthma and other respiratory or heart conditions may be particularly susceptible to the smoke and should ensure they carry their medication and use as appropriate."

If you have any health concerns please call 111 or contact your GP.

The smoke (and potential flame) would be largely confined to the excavation area and dealt with quickly by on-site experts, a joint statement from Herefordshire Council and the police said.

It would pose a very low risk to passing vehicles but if there were any public safety concerns an extended cordon would be set up and further advice issued.

The statement added: “All items of ordnance can pose a danger if not handled correctly.

“As with other phosphorus grenades it is highly unlikely they would spontaneously ignite or detonate if left alone. With this particular device, the glass jar would need to be broken to expose the contents to air, resulting in them setting light.”

A number of homes and businesses were evacuated last night on the following reports of an explosion at the site where excavation work was taking place at around 4.30pm.

Superintendent Sue Thomas of West Mercia Police and Geoff Hughes, director economies, communities and corporate at Herefordshire Council, said: "We would like to stress that risks remain low and there is no need for undue concern, we have measures in place to ensure the safety of road users, nearby homes and businesses and workers on site.

"We would like to thank the community for their continued support, we can assure you that we are working very hard to resolve the situation. The public's understanding and co-operation is very much appreciated."

Further information and updates will be provided when available.