Firefighters tackling a blaze involving 100,000 tonnes of plastic recycling material and a factory unit say it is the largest fire seen in the West Midlands.
The fire has been blamed on Chinese lanterns that dropped on the plastics.
The fire service said 200 firefighters were at the scene in Smethwick. Three of them have been taken to hospital.
A plume of smoke is rising 6,000ft into the air from the fire at the Jayplas depot in Dartmouth Road.
Birmingham International Airport has been alerted, but there is currently no impact on flights.
The fire is on an industrial estate, but the closest residents are being advised to keep windows closed.
The fire service said Dartmouth Road, Halfords Lane and Brasshouse Lane were closed to traffic and that the fire was likely to cause congestion in the area.
It also urged motorists to avoid junction one of the M5 if possible.
Nearby Galton Valley Primary School in Brasshouse Lane is closed because of the road closures.
Area commander Steve Vincent said emergency services were called to the fire at about 23:00 BST on Sunday.
Mr Vincent said: "We haven’t evacuated any of the local residents because this is mainly an industrial area but we have had some minor injuries to some of our firefighters at the scene.
"We’re working with other emergency services and they’re all safely being treated.
"We will have major congestion in this area because we will be fighting this fire for the next few days.
"This is the largest fire that we’ve had in the West Midlands. It is a major fire and we’ve got support from surrounding fire brigades to help us deal with this."
The fire service said its control centre had received more than 200 calls about the blaze and urged people to call 999 only if really necessary.
The ambulance service said it had treated "nine patients for injuries received at the scene".
"Three of these patients were later conveyed to a local hospital as a precautionary measure," a spokesman added.
Area commander Steve Vincent says there are reports the fire "can be seen up to 50 miles away"
Eye-witness Jack Awal said he could see the fire from his home a couple of miles away in Handsworth.
He said: "I heard a loud bang and went outside to see what it was.
"I immediately recognised where the smoke was coming from. I knew it had to be a factory.
"It was like a scene from a movie. There were so many large explosions and loud bangs. It was like a firework display – there were loud crackles and bangs every few seconds."
No-one from Jayplas was available for immediate comment.