An investigation has been launched into an incident aboard a logging ship in Napier Port on Monday night which resulted in six workers being taken to hospital with carbon monoxide poisoning.
While four of the workers were discharged after initial treatment two, a man in his early 20s and one in his late 30s, remained in hospital in a general ward overnight and were eventually discharged this afternoon.
A Napier Port spokesperson said staff from the stevedoring company ISO, which worked with log exporter Ernslaw One, were affected in the emergency call-out.
Maritime New Zealand has confirmed an investigation would be carried out and it was likely to be several weeks before it was concluded.
Investigators, who were at the port yesterday, would be working in with ISO and the shipping company and the investigation would include scene investigations and interviews.
The incident happened about 8pm while the crews were at work on the log ship Nord Yilan.
Fire crews and St John Ambulance paramedics were called to the scene after it is understood a turbo system on the engine of a digger-loader failed and billowed exhaust smoke through the hold area.
A fire service spokesman said the turbo unit on the engine blew and billowed exhaust fumes, causing the workers in the hold to be affected.
Other port workers were able to remove the digger from the hold before the fire service arrived.
It is understood the digger may have briefly caught fire but was out by the time fire crews arrived.
There had been no fire danger to the ship and the fire crews left the scene just after 9.30pm.
Firefighters in full breathing protection gear had checked the hold to make sure the carbon monoxide had dissipated and helped paramedics treat the affected workers.
The Nord Yilan was scheduled to depart port around 7am on Wednesday.
Napier Port Culture and Capability manager Viv Bull said the management's thoughts were with those who had been affected by the gases.
"We are disappointed that an incident has happened on our port," Bull said.
"As the landowner, Napier Port takes a strong interest in the safe practice of companies operating on our site."
More than five Fire Emergency New Zealand crews attended the blaze at 8pm.