PHETCHABUN - Police believe a build up of toxic gas in a fish fermentation tank is what probably killed the five men who were assigned to clean it at a pla-ra plant in this northern province on Monday evening.
The provincial disaster prevention and mitigation office reported that forensic police reached this conclusion after examining the bodies of the five men, aged 30-76 years, found dead at the fermented fish plant in Moo 5 village of tambon Nong Khwai in Lom Sak district about 5.49pm on Monday.
One of the victims was the manager of the plant and a son-in-law of the factory owner.
Officials said the men were assigned to clean an old fermentation tank. Shortly afterwards, the plant owner lost all contact with them. A search revealed the tragedy.
Lom Sak district chief Pakpoom Poomee said later on Tuesday that the tank involved was not being used. It had been closed for five or six months.
The plant owner had told investigators he had ordered it cleaned for use to fill a new order he had received.
The district chief said the tank is three metres wide, four metres long and six metres deep.
“The victims might have inhaled a toxic gas and died from lack of oxygen. There were no signs of assault,” he said.
Mr Pakpoom said the plant had been in business for about two decades and its licence had been renewed annually.
Forensic police would examine samples from the bodies to determine the cause of death, he said.