The silo, five kilometres north of Quandialla, overheated from a chemical reaction at 8pm on Thursday, causing the grain to start burning.

Crews from Young, Wagga, Grenfell and Temora were called in to monitor the area over a series of four-hour shifts when Quandialla Rural Fire Service detected the scene was a hazardous material incident.

An 800 metre exclusion zone was put in place and the specialist Hazmat crew from Sydney were flown to the scene in the Fire and Rescue NSW helicopter.

The specialist crew was able to determine the heat using monitoring and thermal equipment and detect toxic gases the fire was expelling into the atmosphere.

“We were called in at 2am on Friday until daylight – we were just there keeping an eye on it,” Young Fire and Rescue NSW captain Don Smyth said.

“We couldn’t go within 800 metres of the silo,” he said.

Fire and Rescue NSW zone Inspector Jeremy Hood said they had to take all precautions with the silo fire.

“Silos are very dangerous – there is a risk of a dust explosion,” he said.

“Proper monitoring of toxic gases [had to be carried out] and [in situations like this] we have to empty the silo out slowly,” Inspector Hood said.

By 4pm Friday the situation was rendered safe and the silo was safe enough for experts to decant 20 tonnes of the grain.