Up to 1,000 homes faced evacuation on Thursday after a suspected unexploded Second World War device was found at a school.
A 300-metre exclusion zone was set up following the discovery at Lansdown Road in Bath where contractors using a digger unearthed the device at Royal High School.
Those living nearby were evacuated to Bath Racecourse and motorists were asked to find alternative routes as some roads in the area were closed.
The "large" device was discovered at around 4.40pm on Thursday as excavation work was carried out at the the site and the Explosive Ordnance Disposal team was alerted, Avon and Somerset Police Force Incident Manager, Inspector Rob Pearson, said.
At around 6pm, after studying pictures of the find, police were instructed to set up a cordon and evacuate those properties within it.
Mr Pearson said a range of emergency services were involved in a "multi-agency approach to keep people safe".
Inspector Gavin Usher said decisions to evacuate houses "are never taken lightly but during these incidents public safety will always be our primary concern".