Eight fire crews are currently battling a major blaze on an industrial estate in Calne.
Emergency services were called to a unit belonging to Qsil, a metal processing company, following reports of smoke issuing at around 1.30pm today (Saturday).
Around 40 firefighters are attending the serious incident on Porte Marsh Industrial Estate.
Crews from Calne, Chippenham, Devizes, Westlea, Trowbridge, Westbury, Warminster, Swindon, Corsham, Malmesbury and Shaftesbury are at the scene. The aerial ladder platform appliance is also on scene, but is not yet in use.
Wiltshire Police have deployed a drone to assist with monitoring the fire from above.
Officers have closed part of Porte Marsh Road, near Harris Road, as 999 crews work.
Firefighting efforts can be expected to last many hours, with smoke billowing from the roof.
A spokesperson for Dorset and Wiltshire Fire and Rescue Service said: “We are currently dealing with an industrial unit fire on the Porte Marsh estate.
“This is producing acrid smoke so anyone in the local area should keep doors and windows closed if affected.
“We have requested local road closures so please avoid the area.”
A spokesperson for Wiltshire Police said: “Port Marsh Road, Calne, has been closed following a fire at an industrial unit.
“We would urge people to avoid the area while emergency services attend and for those living in the local area to close their windows and doors due to smoke.
“Thank you for your patience.”