A pipe could corrode and leak gas.
Smeg have recalled their built-in barbecue. One of the gas feeder pipes may corrode and gas could leak out.
The affected barbecue has the model number BIBQ1205. It was sold at Kitchen Things and by Applico from April 2014 to March 2015.
Stop using the barbecue and turn the gas off at the source. Disconnect the gas supply. Check the model number and contact Applico. They will arrange for a technician to visit and fix the issue free of charge.