There were around 400 people staying at the centre.
Battling the blaze
It's thought some of the people who escaped had their application to stay in Britain turned down, and they were due to be sent back to their own countries.
There are reports the riot started because staff handcuffed a woman asylum seeker who needed medical help.
Hundreds of firefighters are battling to get the blaze under control.
People who live nearby have been told to lock their doors.