The blast and a subsequent fire occurred on Saturday in a three-story building in the town of St. Helier. British media put the initial death toll from the explosion at one.
Sky News said that there were at least three dead and ten missing after the blast.
The British broadcaster specified, citing the chief officer of the States of Jersey Police, Robin Smith, that residents had reported smelling gas the night before the explosion.
The exact cause of the blast is under investigation.