The Fire Services Department deployed the HazMat team to handle the incident and remove the pesticide powder.

The siblings were taken to hospital and the nearby area was cordoned off to allow emergency vehicles to pass through.

Firefighters were still at the scene until early this morning, removing items from the apartment.

The case was listed as an "odor discovery," and no evacuation was required.

It is believed that the father used multiple bottles of pesticide powder to combat an ant infestation at their Kwong Tak Mansion apartment.