Flames engulfed a fourth tank at an oil storage facility in western Cuba on Tuesday as the raging fire consumes critical fuel supplies on an island grappling with a growing energy crisis.
Firefighters and specialists from Mexico and Venezuela helped fight the blaze in the province of Matanzas with boats, planes and helicopters as they sprayed foam on the containers.
The fire at the Matanzas Supertanker Base has killed at least one person and injured 125 others, with another 14 firefighters still missing.
It also forced officials to shut down a key thermoelectric plant on Monday after it ran out of water, sparking concerns about additional blackouts.
Those injured were treated mostly for burns and smoke inhalation.
More than 20 remain hospitalized, with five of them in critical condition.
The facility caught on fire late Friday after lightning struck one of its tanks, sparking several explosions as it spread over the weekend.