People living next to Venezuela's biggest oil refinery say they smelled a strong odour of sulphur hours before a gas leak ignited in an explosion that killed at least 39 people and injured more than 80.
The Amuay refinery is still burning more than a day after the blast, sending up a thick column of black smoke.
Residents in a neighbourhood next to the refinery said they noticed the unusually strong odour from about 7pm local time on Friday.
Government officials say the blast occurred about 1.15am local time on Saturday when the gas leak created a cloud that ignited.
The cause of the disaster is under investigation.