Three men are fighting for their lives after an accident at a dairy farm in Cloverlea, near Warragul, east of Melbourne.
A farmer was inside a storage tank on the property when he was overcome with gas.
His two sons entered the tank to rescue him, and were also overcome.
Sarah Coster, the wife of one of the sons, says it was a shocking experience.
“It was just total chaos, there was just a horrible scene to see,” she said.
“As soon as I saw his eyes, the look in his eyes.”
The three men are in induced comas at the Alfred and Royal Melbourne hospitals.
Seven others, including two police officers and two paramedics were also affected by the fumes.
Police say the gas came from fermented cattle feed product.