A large factory fire south of Brisbane has been quelled with 20 firefighting crews taking three hours to contain the blaze.

Police are also investigating the cause of the fire at Crestmead which was sparked early on Thursday.

It destroyed half the property, but no one was inside at the time.

A smoke warning was issued for nearby residents because of burning plastic.

“There was a lot of toxic gas appearance around the area,” Queensland Fire and Emergency Services incident controller Craig Lashman told ABC radio.

“Scientific officers were on the scene earlier doing sampling around surrounding areas to ensure the community was safe.”

Queensland Police said a crime scene had been established and an investigation was underway.

– AAP