There is a gas leak in the apartment.
'Fuga' = FOO-ga (leak, also flight/escape). 'Gas' = gas (same as English, invariable).
When you smell gas — the immediate priority is to call the gas emergency line and evacuate.
'Fuga di gas' (gas leak) is the standard Italian term. In Italy, residential gas is predominantly methane (metano) from the national grid or LPG (GPL) in tanks. If you smell gas: do not switch any electrical switches on or off, do not use phones inside, open windows and doors, evacuate, then call from outside: 800.900.999 (national gas emergency) or 112.
Sento odore di gas — cosa devo fare?
I can smell gas — what should I do?
The first thing to ask — immediate evacuation is the answer.
Ho aperto le finestre e sono uscito/a dall'appartamento.
I've opened the windows and left the apartment.
Confirm correct procedure already followed.
Il contatore del gas è nel vano scale — posso chiuderlo?
The gas meter is in the stairwell — can I close it?
Only if trained — turning off the main valve stops the flow.
Italian gas distribution is managed by regional distributors (Snam Rete Gas for the national grid). All Italian gas appliances must carry CE marking and be installed by certified professionals (CIG certification). Annual gas appliance checks are strongly recommended. LPG (GPL) cylinders must be stored in ventilated areas — they are denser than air and collect at floor level.