A spectacular fire at a newly opened car franchise in Frankton was caused by a spark from an electric drill, an investigation has found.
The May 20 blaze at Macaulay Motors left a staff member with burns to his hands, destroyed three cars and prompted a large-scale callout by Fire and Emergency New Zealand.
In his report, Fenz investigator John Smalls found the fire was caused by a mechanic accidentally igniting petrol vapour while drilling a hole in a fuel tank.
The mechanic told Mr Smalls he drilled the hole to remove fuel from the vehicle's plastic fuel tank. The Mazda CX-5 was on a hoist with an empty drum underneath to catch the fuel.
He drilled one hole, the fuel sprayed out and immediately caught fire.
He told Mr Smalls it was "normal procedure" to remove fuel that way; because of an additive that crystallised in the fuel system, the fuel could not be siphoned out.
The entire fuel system, including the tank, would have been replaced.
The report said the drill's instructions stated it should not be operated in "explosive atmospheres such as in the presence of flammable liquids, gases or dust" because it had electric brushes in its motor that could emit sparks.
Staff working nearby attempted to fight the fire using three fire extinguishers.
Although the fire caused smoke damage to the workshop's interior, it ventilated through the roof early enough in its development that it did not spread horizontally beyond the three cars that were destroyed, Mr Smalls said.
More than 30 volunteer firefighters and five fire trucks from the Queenstown, Frankton and Arrowtown stations responded.
The blaze was brought under control within about half an hour of the 9.36am alarm.
The company did not want to comment.
