Lightning struck a crude oil storage tank in the Cuban city of Matanzas, causing a spreading fire that led to four explosions which injured nearly 80 people and left 17 firefighters missing, authorities said.
Firefighters and other specialists were still trying to quell the blaze at the Matanzas Supertanker Base, which began during a thunderstorm Friday night local time.
The official Cuban News Agency said the lightning strike set one tank on fire and the blaze later spread to a second tank.
The injured are being treated at the Faustino Perez in Matanza but seven of the most seriously injured had to be transferred to Havana.
Residents of Dubrocq, the closest neighbourhood to the fire, were evacuated, but the thick smoke and strong smell of sulfur is driving residents from other further districts to voluntarily leave their houses.
The accident comes as Cuba struggles with fuel shortages. There was no immediate word on how much oil had burned or was in danger at the tank farm, which stores oil used to fuel electricity production.