An attempt to force Oxfordshire County Council to rethink plans to sign up to an incinerator near Bicester has ended in failure.
A cross-party group of 12 councillors called in the decision to commit to a 25-year deal with waste firm Viridor for the plant at Ardley.
The councillors said it was not in the interests of the people of Oxfordshire.
But the scrutiny committee voted five to three in favour of the scheme, with two members abstaining.
It means Oxfordshire County Council will sign the contract in September, despite Viridor not having planning permission.
A planning inspector is due to report the outcome of a public inquiry next month.
The council says an incinerator represents the best deal to get rid of the county's non-recyclable waste.