Multiple firefighters spent most of today battling a blaze inside two storage sheds containing palm kernel in Mount Maunganui.
Fire and Emergency NZ shift manager Daniel Nicholson said the first 111 call was received about the Waimarie St blaze at 9.01 am.
It was understood the fire, close to a cargo containers depot was at a nearby timber yard but later that was revised to two storage sheds at a neighbouring site, he said.
However, the attending firefighters were "actively protecting" the nearby Arbor Resources Limited' timber yard on Kereiti St, Nicholson said.
A worker at the nearby Burnsco store, who only wished to be known as Mike, said he called 111 after seeing smoke, then flames, coming from the roof of one of the storage sheds.
"The smoke was so thick the police shut the whole street down for at least half an hour, which meant our customers were turned away," Mike said.
One end of Waimarie St remained cordoned off last night.
Thick smoke billowed across Hewletts Rd towards Tauranga Airport, prompting police to issue a statement warning motorists to exercise caution and be aware of potential delays.
Port of Tauranga's chief Mark Cairns said he visited the site at 10.30am yesterday and the fire began inside Glencore Grain NZ's southern palm kernel storage shed.
The company had operated on the site for about five years, he said.
"Fortunately, no one was injured which was our first concern, and did not spread to other buildings or pose a risk to the Port's container operations."
The palm kernel was likely to be left smouldering for some time until decisions could be made about what do next, Cairns said.
"While there are various speculations about what may have caused the fire, but that is for the fire investigator to establish," he said.
It took several hours for the fire to be contained and brought under control.
Thirteen fire appliances attended the blaze.
Among those were two from Rotorua, one from Hamilton and several from the Western Bay of Plenty, including Ōmokoroa, Mount Maunganui, Greerton and Tauranga brigades.
Some of the firefighters were expected to remain at the scene overnight.
Nicholson said heavy machinery was being brought in to remove the smouldering product to enable the fire to be completely extinguished.
Twelve fire appliances were still at the scene at 3pm yesterday.
A fire investigator Luke Burgess was also at the scene yesterday, but he was too busy to talk about the potential cause of the blaze.
Several fire brigades responded including crews from the Tauranga and Mount Maunganui stations, he said.