Chemical factory burn-off in Sydney's south sends smoke billowing across city

A controlled burn-off from a chemical factory's chimney stack in Sydney's south has sent thick black smoke over the city. 

The fire burned from a chimney at the Qenos plastics plant in Botany, with plumes of smoke drifting over the area near Sydney Airport.

Qenos later said the burn-off was necessary after the plant lost power, with gases inside the factory needing to be funnelled into the flare and ignited. 

Fire and Rescue NSW kept a close eye on the burn-off but said it posed no risk to the community. 

The Environmental Protection Agency has launched an investigation into the fire. 

Qenos was fined in 2012 over a similar flare event. 

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