Three fire engines from Bognor and Chichester responded to the blaze at a property in Station Road at about 11pm.
Photos show a large response from other emergency services, with two ambulances and six police cars on the scene.
Nearby residents were asked to keep their doors and windows closed while firefighters worked.
A spokesperson for West Sussex Fire and Rescue said: “Please avoid the area to allow firefighters to work safely.”
Sussex Police confirmed six men have been arrested following the incident.
Nearby residents were asked to keep their doors and windows closed while firefighters worked.