Fifty people from a Brixton apartment complex had to be evacuated as a fire spread quickly after what witnesses said was a series of explosions. Three people have been hospitalized with smoke inhalation.

“We were having lunch and heard a small explosion and we saw a black cloud of smoke going up and the growing fire,” an eyewitness near to the Canterbury Crescent complex told the London Evening Standard. “Some seconds after the first explosion he heard one or two more, also small. There were some people in the field in front, I guess calling the emergencies.”

The local fire station is located about 100 yards from the tower block, and the London Fire Brigade (LFB) said that 72 firefighters and 10 fire engines were dispatched to put out the flame.

“The ground floor flat was badly damaged by the blaze. The fire has also damaged a flat on the first and second floors of the 16-storey block,” said a statement from LFB. “Around 50 people were evacuated from the block. A man, a pregnant woman and girl were suffering with smoke inhalation and were taken to hospital by London Ambulance Service crews.”

LFB said that it is investigating the cause of the fire, which could be seen from miles away in south London, provoking a widespread reaction on social media.