A major fire broke out last night at an industrial estate in Highbridge, causing the M5 to temporarily close.
Eight fire engines attended the Walrow estate on Commerce Way to deal with the "massive" blaze.
A picture taken by a witness at around 6.20pm showed thick dark smoke pouring across the road.
The witness said: "I came out of my work cleaning at the Green Goblet [ecocup supplier] and heard loud popping sounds, and almost whooshes, like a firework being set off.
"But then I saw all the black smoke. My friend is a cleaner behind me in another unit and I ran down worried it was her, but it was further down.
"When I got there, there were already three fire engines, then more, around eight when I left [before 6.45pm]. People were moving cars off the front to allow fire engines and police to get closer."
Fire engines from Burnham-on-sea, Bridgwater, Cheddar, Taunton and Avon fire Service took on the blaze.
A statement from Devon and Somerset Fire and Rescue Service said: "At 21:34 crews confirmed that the building used as a vehicle workshop and storage building is 60% damaged by fire and 100% damaged by smoke. 8 Breathing apparatus, 1 Hose reel jet, 5 main jets, 1 Ariel platform ladder, 1 triple extension ladder, 1 light portable pump and small tools were used to extinguish the fire.
"The cause of the fire is yet to be determined."