Homes in Calderdale have been evacuated after the bomb disposal team was mobilised to a property.
The army disposal team was called this morning from their base in Catterick, North Yorkshire.
A spokesperson for West Yorkshire Police said: "Police are in attendance at a property on Swift Place, Ripponden, after a reported hand grenade was found at a property.
"The Explosive Ordnance Disposal team has been called to examine the device."
Since the report this morning the bomb disposal team has stood down.
However, a police presence still remains at the scene.
The specialist EOD army unit is responsible for counter terrorist bomb disposal and Explosive Ordnance Disposal (EOD), the recovery and safe disposal of conventional munitions.
The army regiment also inspect and licence ammunition storage and enforce explosives safety regulations.
Keep up-to-date with all the latest news and breaking incidents in Halifax by joining our dedicated Facebook group here