The fire has spread and caused several explosions.
Close to 80 people have been injured and 17 firefighters are missing, according to Cuban authorities.
The fire started on Friday evening local time and was not yet under control on Saturday.
Around 800 people have been evacuated from a residential area nearby.
Satellite images from the area show a thick plume of black smoke stretching west as far as the capital, Havana, ten miles away.
Cuban President Miguel Díaz-Canel visited the area on Saturday.
The accident occurs at the same time as Cuba suffers from a lack of fuel.
There is no information about a lot of oil that has burned or is at risk of burning.