Four residents needed hospital treatment after emergency services were alerted to a chemical smell in a block of flats.
Firefighters, police officers and paramedics were called to Greenhill Court in Lodge Close at 9pm on Tuesday.
Fire crews wore breathing apparatus and specialist detection equipment to try to identify the unknown chemicals involved.
Oxfordshire Fire and Rescue Service sent four engines from stations in Banbury, Deddington and Oxford.
South Central Ambulance Service and Thames Valley Police also attended.
- Our top stories
6:50pm Sunday 1st February 2015
A WOMAN was sexually assaulted in the Bankside area of Banbury today.
UPDATE: Man left with serious head injuries after being hit with wooden item during fight in Bicester
3:17pm Saturday 31st January 2015
THREE men have been arrested after a man was left with "serious injuries," police say.
10:29am Sunday 1st February 2015
TRAINS from Oxford to the north of England will be disrupted until at least Tuesday after a landslip on Saturday.
7:43am Saturday 31st January 2015
IT'S been snowing overnight in Oxfordshire and here's some of the pictures our readers have sent in.
9:00am Saturday 31st January 2015
THE POPPY Appeal’s fundraising target has been smashed in the county.
1:20pm Saturday 31st January 2015
A British military healthcare worker has been brought back to England for Ebola monitoring after suffering a needle-stick injury while treating a person in Sierra Leone.