A major fire at Airedale International’s factory on the outskirts of Leeds on Friday has been tackled by 100 firefighters.
Roads were closed, causing traffic disruption, and motorists were urged to avoid the area.
About 20 fire engines were at the site and firefighters were expected to remain there overnight and well into Saturday, the fire service said.
Dave Walton, Assistant Chief Fire Officer, said: “This is a very significant incident that’s calling in resources from right across West Yorkshire.”
Mr Walton said it was too early to know the cause of the blaze but a “robust investigation” would take place once it was safe for investigators to enter the building.
The A65 New Road Side in Rawdon was closed and congestion was building on other neighbouring routes.
Police urged drivers to stay away from the Calverley, Horsforth and Rawdon areas “unless absolutely necessary”.
Smoke from the fire could be seen for miles.
Graham Branston emailed BBC News and said: “As I write, thick smoke 100ft high is still bellowing out of the works and has been for around an hour.”
Leanne Lister tweeted: “The fire in Rawdon looks and sounds absolutely horrendous.”