"I could also hear the driver shouting "brake failure, brake failure".
The tanker was heading out of Lagos towards the Lagos-Ibadan Expressway when the crash occurred, engulfing at least 50 vehicles, leaving nine persons dead and four others injured.
The tanker, five buses, two trucks, a tricycle and 45 cars got burnt.
Fuel explosions are common in Nigeria, where oil is transported on poor roads by trucks in a poor state of fix, according to AFP.
"We are removing the burnt vehicles from the road in order to ease traffic congestion". A representative from the Federal Road Safety Corp (FRSC) told the BBC that the tanker lost control as it approached a bridge, and ended up falling on its side. The blaze quickly spread from vehicle to vehicle.
Images published on social media showed massive clouds of black smoke billowing into the sky from vehicles burning on the road.
Nigeria's President Muhammadu Buhari said he was "very sad to learn of the tragic loss of lives".
"As a government, we would not relent in putting measures in place to ensure safety of lives and property of all residents", said Lagos state government spokesman Kehinde Bamigbetan in an emailed statement.
Eyewitnesses, however, said the death toll could be higher as many people were trapped in their cars at the time of this report.