Wiltshire Fire & Rescue Service were called to Swindon Skips in Brindley Close, on the Cheney Manor Industrial Estate, at 8.48pm last night, where they found some 750 tonnes of building and timber recycling material well alight.
Smoke from the fire can be seen from some considerable distance away.
Air quality is being monitored by Public Health England and people living locally are advised to keep windows and doors shut as a precaution if they are concerned.
The site is adjacent to the main railway line – trains were stopped for a time overnight but are now travelling through under caution.
The Fire & Rescue Service are expecting to be at the scene for most of the day.
A fire investigation will be carried out in due course; as yet, it is not known how the blaze started.