The heat from a massive fire which destroyed two industrial buildings near Kerikeri was so intense it melted a firefighter's face mask, the town's fire chief says.
The blaze, on Kapiro Rd, off State Highway 10 north of Waipapa, destroyed a large steel shed and an adjoining building which was home to several people as well as housing workshops and offices.
The alarm was raised about 12.40pm on Saturday with firefighters responding from Kerikeri, Ōkaihau, Kaikohe Rural and the recently established Bay of Islands Airport Rescue Fire.
Firefighters had to wear breathing apparatus to fight flames which leapt more than 10m in the air, fuelled by tyres, paint and solvents in the shed.
At one point the heat was so intense firefighters were forced to retreat.
The blaze was under control by 2pm but Kerikeri firefighters didn't get back to the station until after 8pm.
The volunteers had just finished cleaning and stowing their gear when they were called out to a medical emergency on Purerua Peninsula.
Kerikeri fire chief Les Wasson praised their efforts against the brigade's biggest blaze this year.
''It was an awesome effort by all the crews. I was rapt with their performance, they did the best they could under the conditions. The heat was so intense it was unbelievable. It was so hot one guy's mask melted.''
The biggest challenge was getting enough water, Wasson said.
The nearest hydrant was 2km east on Kapiro Rd so fire trucks had to shuttle water constantly. They were joined by a bulk water tanker filling up at a water treatment plant.
The other issue was the LPG and oxy-acetylene gas cylinders in both buildings.
Firefighters had no way of knowing if they were full so they had to be kept cool to prevent explosions.
Wasson said the fire started in a building at the front of the property then spread to a large shed originally built as a packhouse and later used as a contractor's depot.
Until Saturday it was used by at least four different businesses including a road marking company. Drums of paint may have caused the explosions which could be heard.
Firefighters initially tried to stop the blaze spreading to the shed but the amount of flammable material stored inside made that impossible.
''As soon as it broached the roof I knew we'd lost it.''
Firefighters did, however, stop the flames spreading to a hedgerow and a nearby house.
No one was injured but a number of people have been left homeless and have lost all their belongings.
The Kerikeri-based Rapid Relief Team, made up of Brethren Church volunteers, happened to be driving past after helping at the half marathon. They provided tea and water for weary firefighters.
A Fire and Emergency canteen truck was also brought in from Whangārei.
An investigation into the cause of the fire is under way.