The 17 missing people are "firefighters who were in the area closest to the fire" when an explosion took place, reported the Cuban presidency, which "requested the help and advice of friendly countries with experience in the petroleum sector.
On Twitter, President Miguel Diaz-Canel said that controlling the fire "could take time".
Three injured are in critical condition, three in very serious condition and 12 people are seriously injured, according to the official Granma newspaper.
The fire broke out on Friday evening when lightning struck one of the tanks of the oil depot in the suburbs of Matanzas, a city of 140,000 inhabitants 100 kilometers east of Havana. The fire then spread to a second tank.
According to Granma, "there was a failure in the lightning rod system which could not withstand the power of the electric discharge".
Mario Sabines Lorenzo, governor of Matanzas, said about 800 people have been evacuated.
According to Asbel Leal, director of trade and supply at the Cuban Petroleum Union (Cupet), the first tank "contained about 26,000 cubic meters of domestic crude, or about 50% of its maximum capacity" at the time of the disaster. . The second tank contained 52,000 cubic meters of fuel oil.
According to him, Cuba had never been confronted with a fire of "the magnitude of today".
The deposit supplies the Antonio Guiteras power plant, the largest in Cuba, but pumping to the plant has not stopped, Granma said.
This fire comes as the island has been facing supply difficulties since May to meet the increased demand for electricity due to the summer heat.
The authorities must carry out rotating cuts, which can go up to 12 hours a day in certain regions of the country, triggering the anger of exasperated residents who have organized around twenty demonstrations.