A fumigation chemical used to treat cargo coming into the Port of Tauranga ‘spontaneously combusted' overnight causing people to evacuate from the Jean Batten Drive area.

About 25 firefighters from Tauranga, Mount Maunganui and Greerton, as well as a specialised Hazmat unit were called to a depot next to Bunnings after reports of an explosion and subsequent fire about 8pm.

The containers the fumigant was stored in.

Police had cordons in place on Hewletts Road to control the traffic coming in and out of Jean Batten Drive. Photo: Tracy Hardy.

Tauranga Fire Brigade senior station officer Mark Keller says a chemical infused fumigant spontaneously combusted causing a fire and toxic smoke.

'It was a nasty chemical and we had to get police to evacuate people in the Mount industrial area, east of Bunnings, as the smoke was drifting in that direction and towards Bayfair. People were evacuated 1.5km from the area.

'Our first concern was how toxic smoke was and how far it would drift with the south-west wind we had last night, as well as getting the fire out.”

The chemicals used in the fumigant proved difficult to put out once on fire, so firefighters used an aerial appliance to dump 1000 litres of water on it all at once, smothering the fire and extinguishing the flames.

'It was then a matter of making sure it stayed out as chemicals like this tend to reignite. We searched for a container we could put it in and submerged it in water to make sure it didn't reignite.”

While firefighters dealt with the burning chemical, police placed cordons in the area to control traffic coming in and out of Jean Batten Drive.

Officers were stationed at the intersection of Hewletts Road and Maunganui Road and at Hewletts Road and Totara Street, while other officers evacuated people from the immediate area.

'The police did a great job. Working with them allowed us to focus on getting the fire out as soon as possible,” says Mark.

St John Paramedics were treating police officers at the scene as they had been exposed to the toxic smoke as they evacuated people from the area.

Mark believes no one else was affected by the smoke.

'They were in the direct path of the smoke. They were given lots of water to flush their system and once the chemical is out there is normally no lasting effects. I don't think anyone was transported to hospital.

'We spent about five hours at the scene making sure the fire was out and everything was safe for people to return back to the area.

'I'm not sure how long people were evacuated for, I think it may have been around four hours.”

Tauranga Airport was also shut down during the incident, but airport staff managed to evacuate people from the airport using the road which runs west behind Bunnings.

Tauranga Airport rescue fire and security's Chris Walters says two 50 seater planes landed at the airport at 9pm.

"During both of these landings the airport was under lock down so for each flight we got all of our customers in their cars qued up together at the base of the control tower and led them across the airfield and out onto Totara st to the Hewletts rd intersection which allowed us to remain up wind of the incident.

"I would like to thank the passengers who opened their doors and offered and assisted with taking other passengers off these flights to the intersection of Totara and Hewletts so they could be picked up by their respective pairs here as they couldnt get into the terminal to be uplifted."

Chris says it was a fantastic show of how the community can work together with complete strangers in times of need.