The blaze which was seen as far away as Penarth Pier broke out on August 7 in Rooks Bridge, near Burnham-on-Sea, Somerset.
The incident prompted the closure of a section of the A38, leading to heavy delays.
Emergency services responded to the fire, which after further calls indicating it involved a garage was upgraded to a commercial property fire.
A spokesman for Avon and Somerset Police said: “We have been supporting the fire service with closures on the A38 at Rooksbridge, at the junctions with Mudgley Road, Mendip Road, Fletchers Lane, Old Bristol Road and the A370 South.”
Motorists were advised to stay away from the area.
According to the Somerset County Gazette, one driver wrote on social media: “If you are coming off the M5 at Burnham to avoid traffic, the A38 is currently closed through Rooksbridge due to a fire.”
Devon and Somerset Fire and Rescue Service said teams from Cheddar and Burnham-on-Sea were first on the scene.
The response was soon upgraded to a commercial property fire, prompting a larger response.
Crews from Bridgwater, Winscombe, and Weston-super-Mare attended, along with an aerial ladder platform from Taunton.
A spokesman for Devon and Somerset Fire and Rescue Service said: “Firefighters discovered a detached building measuring approximately 10 metres by 20 metres fully involved in fire, with a number of vehicles also alight.”
Crews used breathing apparatus, attack jets and water supplies from a nearby hydrant to tackle the blaze.
The spokesman said: “Power cables were affected by the fire, prompting National Grid to attend and isolate the electricity supply.
“A neighbouring property was evacuated as a precaution because of its proximity to the fire.
“The fire service also confirmed cylinders were located inside the garage and were being cooled by firefighters, while a hazardous materials officer attended to support the operation.”
Crews used ground monitors, a hose reel jet, and thermal imaging cameras as they worked to bring the fire under control.
