Residents living near Charles Henry Street in the Highgate area of the city have been advised to keep windows and doors closed after the fire broke out at around 2.30am.
Images published by the West Midlands Fire Service show the fire raging at an industrial unit.
Along with dozens of firefighters, two specialist aerial appliances were also dispatched to the scene.
The fire service first tweeted at 5.21am to say: "Incident currently in progress. 70 Firefighters are currently working with 2 specialist aerial appliances. Avoid the area if possible due to road closures. Keep windows and doors closed in the area."
Two hours later more images revealed some of the damage after fire crews had managed to dampen down the flames.
A spokesman for the fire service said crews were called at 2.37am, with the first firefighters arriving within five minutes.
"16 appliances and over 70 firefighters tackled the fire," he said.
Tweeting at 7.16am, the fire service said it was identifying hot spots within the building using a drone, adding: "Reduced number of Firefighters on scene. Road closure to remain throughout the day at Macdonald Street from the junction of Charles Henry street until junction Bissel street also Charles Henry street from junction Macdonald Street."
"Our drone team were also in attendance and using our drones' thermal imaging capability, we were able to identify hot spots in the building and direct resources appropriately. Our colleagues from West Midlands Police closed roads in the area to keep the public safe and some road closures remain this morning.
"Crews worked tirelessly to contain the fire to the building in which it started, using high volume pumps from the nearby River Rea, covering jets and main jets.
"We have now scaled down to a watching brief, with some crews remaining on site monitoring for smoke and fire hotspots. Fire investigation crews are on site and the cause of the fire is unknown at this time."
West Midlands Ambulance Service also attended.
A spokesperson said: "We were called by the fire service at 2:54am to a fire at a building at the junction of Macdonald Street and Rea Street South in Birmingham. We sent two paramedic officers and the Hazardous Area Response Team (HART) to the scene. However, there were no patients who required treatment and we were stood down from the scene.”