Firefighters on Tuesday finally overcame what officials described as the worst fire in Cuba's history that over four days destroyed more than 40% of the nation’s main fuel storage facility and caused massive blackouts across the island.

Reuters reported witnesses as saying the raging flames that destroyed four of the eight tanks of the Matanzas Supertanker port had died down and the towering plumes of thick black smoke streaming from the area were now mostly grey. As of Monday morning, three of the eight tanks had actually collapsed.

The fire, initially caused by a lightning strike on Friday 5 August, killed one firefighter and injured more than 100 other people — five remain in a critical condition — while at least another 14 firefighters have been reported as missing. A second fire broke out on Saturday.

On Tuesday, more helicopters joined the effort to put out the fire, along with two fireboats sent by Mexico along with heavy firefighting equipment. Mexico and Cuba’s political ally Venezuela were among those that had sent experts and specialist equipment and chemicals to help fight the massive blaze.

"We have not yet been able to access the impact area due to the conditions. There is combustion and so we cannot risk our lives for now," firefighter Rafael Perez Garriga told Reuters around noon local time on Tuesday.

Later in the day firefighters for the first time were entering the area and spraying foam and water on the still smouldering remains.

"Today we have managed to control the fire," Rolando Vecino, head of transport for the Ministry of the Interior, said on state-run television from the scene.

Blaze site: firefighters work to put out the deadly blaze Photo: AP/SCANPIX

According to state-owned oil company Cupet, storage tank 52 — that was first struck by lightning contained around 26,000 cubic metres of crude — while the second affected tank contained around 50,000 cubic metres of oil.

Authorities said that no oil had contaminated the nearby Matanzas Bay. However, they warned residents as far away as Havana to wear face masks and avoid acid rain due to the massive plume of smoke the fire generated.

Mario Sabines, governor of Matanzas province, about 60 miles (96 kilometres) from the capital city Havana, reportedly said the flames spread like an “Olympic torch” from one tank to the next, turning each into a “cauldron”.