Large areas of the Nigerian economic capital Lagos were enveloped in a dense cloud of mysterious fumes on Wednesday, triggering health concerns.
Residents in the heavily-populated inner city districts of Ikeja, Oregun and Gbagada complained of irritation to their eyes and stomach pains after what appeared to be smoke filled the streets.
"The smoke is attributed to a petroleum pipeline rupture. Smoke samples are under analysis. There is no cause for alarm so far," city health commissioner Bisi Adesina said on television.
Police spokesman Bode Ojaduni said: "We discovered the heavy smoke this morning, we have sent our men out to investigate it. For now we cannot accertain the source and the nature of the smoke."
Lagos is Africa's largest city, with more than 16 million residents living closely packed in what is often run-down slum accommodation. Pollution is a constant hazard.
Television images of the latest leakage showed a dense, fog-like grey cloud lying over the city centre, reducing visibility in some areas to less than 20 yards (metres).
