BOMB disposal experts have been called to Banbury following the discovery of an unidentified device giving off fumes on a building site.
Middleton Road in Grimsbury is closed in both directions between the Priory Vale Road junction and the Ermont Way junction.
Thames Valley Police spokesman Craig Evry said police were called at 12.40pm today after contractors working at a building site in Middleton Road found an item which let off fumes when it was disturbed.
He said: "The substance has not yet been identified but as a precaution a cordon has been put in place and residents have been advised to close their windows.
"Army bomb disposal staff from 11 EOD Regiment are attending to offer their expertise but it is not clear yet what the item is."
He added that firefighters were also attending the incident.