On July 4, Kelly Kemble Kerr and her 11-year-old son Kelly died after a heater in their View St, Manapouri, home caught fire and rapidly engulfed the rest of their home, a report said.
In documents released to the Otago Daily Times, an inquiry into the blaze by fire investigator Murray Milne-Maresca found the home had no working smoke alarms, there was no working cellphone at the property, an internal room used for storage was filled with combustible materials and there was only one entry and exit unblocked by furniture.
The home also had no insulation and was known to be cold. The occupants relied on heaters and a Yunca fire to stay warm.
The temperature the night the fire took hold was about -0.1°C.
About 3.30am, Fire and Emergency New Zealand received multiple calls about the fire.
Witnesses reported hearing an explosion during the fire which, when investigated, was found to be caused by cement boards absorbing water over time.
When the fire broke out, the water in the boards boiled, converted to steam and exploded.
Glass windows quickly broke, creating a continuous airflow to stoke the flames.
Timber framing was all that was left, which quickly burnt and caused the ceiling to collapse.
Media reported at the time Ms Kerr’s partner, Jason Hoggard, was working at sea when the fire occurred.
In one of the bedrooms, fire investigators found a wall-mounted panel heater and an electric oil column heater which showed heat damage.
"The wall-mounted panel heater was totally destroyed in the fire and operates at a relatively low temperature — it was unlikely to ignite any surrounding objects.
"These heaters were not the cause of the fire," Mr Milne-Maresca said in the report.
Investigators found a 3kW heater under the floorboards of the bedroom had combustible materials melted into its grill.
"Materials were either draped or had fallen on to the heater causing this fire which would of started very quickly based on the heater rated output," Mr Milne-Maresca found.
The sliding door to the hallway was open when the fire took hold, allowing the blaze to spread around the home.
"The heater showed signs that combustible materials has come in contact with it and moulded to the grill indicating bedding or similar material has ignited.
"Burn patterns, charring and the loss of materials indicated the fire started between the beds, first igniting combustible materials, and spreading through the dwelling assisted by the wind and the ventilation factors."
Mr Milne-Maresca reported he had four hypotheses into possible causes, or a combination of causes, into the fire.
Those were that the heater’s lead or plug had overheated causing ignition, the heater malfunctioned, radiant heat ignited the bedding, or combustible materials were draped or had fallen on to the heater and ignited.
