A strong smell of burning plastic prompted staff at a downwind childcare centre to keep the children indoors until the fire was out. Police had initially considered evacuating the youngsters.
Fire and Emergency Muriwhenua area commander Wipari Henwood said the first fire crews needed some time to establish a water supply. Once that was done they were able to go in to contain the fire to the oven.
When the fire was out, about 3.45pm, they allowed a cooling off period before opening the oven and verifying it had been extinguished.
Waipapa Rd was down to one lane at times as firefighters laid hoses across the road from the nearest hydrant on the corner of Mawson Ave. Fire tankers and even a commercial water tanker shuttled water to the fire pumps.
The cause of the blaze, or the effect it will have on production, was not known at edition time yesterday.
Promax makes large tanks for industrial, transport, farm and domestic use. The company also produces septic tanks and even dog kennels.