Homes were evacuated and two people arrested after police searched a property under the Explosive Substances Act.
Essex Police put a 100m (328ft) cordon in place after searching the home in Meadgate Avenue, in the Great Baddow area of Chelmsford, on Tuesday.
Ahead of the warrant at the address, a 34-year-old man, from Chelmsford, was arrested on suspicion of an offence under Section 4 of the Explosive Substances Act 1883.
One “suspicious” item was removed from the property, the force said.