Silesia provincial Gov. Jaroslaw Wieczorek said the bodies of four people, including a child, were found and rescuers continued to comb by hand through the debris in search of those missing. The temperature is sub-freezing and there is some snow in the southern mountain resort of Szczyrk where the explosion occurred.
Earlier firefighters said that nine members of two families lived in the three-story house. One person was not at home at the time of the explosion Wednesday evening. Head of regional firefighters, Jacek Kleszczewski, said about a half of the debris had been checked and the action now focused on cutting through the collapsed ceiling structures.
A suspected cause was a gas leak during work on a pipeline. Prosecutors were on the site and are investigating. Footage on TVN24 showed firefighters and rescuers working through a huge heap of bricks that remained of the house.
A spokesman for Poland's gas company, Artur Michniewicz, said that after the blast, authorities cut off gas for a large part of the town for security reasons.