The accelerator of a diesel van was stuck down.
Fire crews have shared a video to explain what all the smoke was about in Sidmouth last night (Monday 7th October).
They were in the middle of a drill, when they were called to reports of a small car fire on the High Street.
The accelerator on the small van was stuck down, and diesel fumes filled the High Street - including a shop.
Crews used a van to clear the fumes from the shop and said "Diesel fumes while very unpleasant carry a lower amount of carbon monoxide than a petrol engine."
The van eventually ran out of fuel.
You can see a video of the incident on the Radio Exe Facebook page.
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