Witney's main post office in Market Square had to be closed for the day after a member of staff fell ill from an allergic reaction.
Carpets in the building were cleaned after close of business last night and, according to Post Office spokesman Richard Hall, there was a build-up of fumes.
He added: "The place is being ventilated and it should be open as normal tomorrow.
"Our apologies to customers, but we cannot take risks with the safety of our customers and staff."
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