Southland Regional Council says the threat from a fire in a mound of fertiliser near the town of Winton has been dealt with.
Fire crews were sent to the Fertiliser New Zealand plant in an old limeworks shortly before 8am on Thursday.
The fire, in a five-tonne heap of sulphur fertiliser, produced significant fumes.
The regional council says a hazards officer advised the Fire Service on how to deal with the fire.
Plant owner John McDougall says he has no idea how the fire started, as no one had been anywhere near it.