The scene of a house explosion that shook southwest Kitchener was busy again Tuesday as investigators continued to try and determine what caused the blast.

The explosion occurred shortly before midnight Saturday night at the corner of Activa Avenue and Isaiah Drive.

A family of four was home at the time. All four members of the Nguyen family were taken to hospital. Three were quickly released, while the father remains in hospital.

Heavy equipment has been brought in to dig through the rubble and remains of the house.

“It’s a very painstaking process. We’re going to be looking at each layer of the building as we take it off,” said Tom Ruggle, Kitchener’s chief fire prevention officer.

Officials say hydro and natural gas has been restored to all residents in the area.

Isaiah Drivewill remain closed for most of the week as the investigation continues.

“We’ll be here for at least another two days,” said Ruggle.

Police are not involved in the investigation as the explosion is not believed to be suspicious in nature.