Tyres were dumped behind the Cadbury's factory in Sheffield and set aloght in an arson attack this morning.
The blaze, off Penistone Road, Owlerton, was discovered at 6am after plumes of thick, black smoke were spotted.
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Firefighters said fly-tippers had dumped the tyres and set them alight.
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They spent around 30 minutes extinguishing the flames and damping down.
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Anyone with information should call South Yorkshire Police on 101.