About 50 people were evacuated from food-production company Hansells Masterton after smoke from a faulty motor or air conditioner filled a manufacturing area at the site yesterday morning.
Company chairman Alan Stewart said workers in the second floor area at the Opaki Rd site had seen smoke filling the room and raised the alarm before evacuating the premises about 9.20am yesterday.
"There was no fire found, it was only smoke. We think it was a faulty air-conditioning unit. Everybody got out safely."
Mr Stewart said up to 10 building staff were evacuated from the affected area alongside 40 Hansells workers. Personnel were to work in other areas at the site until the affected room had the all-clear.
Mr Stewart said sugars, flavours and colours were mixed in the room where the smoke was seen and the incident would have no effect on production. No highly flammable or explosive chemicals or materials were stored in the manufacturing area.
He said the evacuation was carried out without incident and he was satisfied with the safety checks and balances at the site.
"Anything is a crisis but we've actually finished all our July work and were starting on August anyway, so it will have no effect at all on production."
Masterton Fire Service station officer Mike Cornford said fire crews from Masterton were scrambled to the factory, and firefighters used breathing apparatus and thermal imaging cameras to track down the source of the smoke.
"The upstairs room was reasonably full of smoke but we weren't able to find the cause immediately. An investigation was launched and we believe it was a faulty motor or ventilation unit."
He said the factory building had been immediately cleared of staff and one worker had been treated for mild smoke inhalation at the site. Police were also at the scene yesterday.