A 100 square meter sulfur pile was on fire at an industrial site in Kwinana, Perth.
Fire fighters were called to Bis Industries on Port Road where five per cent of the 70,000 tonne pile was smouldering, The West Australian reports.
When sulfur burns, it produces sulfur dioxide, a toxic chemical that produces a strong odour.
More than 20 firefighters worked to extinguish the blaze, with chemical analysts and Department of Mines and Petroleum dangerous good officers also attending the scene.
It has not been identified whether anyone was on site during the time of the fire however no one is believed to be injured.