The police and the Fire Service were called to a house in Garden Lane just before 8 am where a gas pipe had ruptured and was pumping out highly explosive gas.
Parts of Devonshire Place and Val Plaisant were sealed off as two teams of firefighters went into the house.
Neighbours were evacuated and others living nearby were told to stay in inside and keep their doors closed.
The firefighters’ goal was to use a putty-type plug to stem the flow of gas from an old and badly corroded pipe.
Station officer Clive Russell, of the Fire Service, said: ‘The potential for an explosive mixture was minimised by positioning a high-pressure water jet to produce a vapour cloud around the rupture area.
A team of gas engineers from Jersey Gas isolated the leak and dug down to the main outside the building before cutting and capping the supply pipe.’