DUBAI, United Arab Emirates (AFP) — An abandoned tanker carrying more than one million barrels of crude oil could contaminate vast areas of the Red Sea in a severe, long-term environmental disaster if it breaks up or explodes, experts warn.

The Greek-flagged Sounion, struck on 21 August by Yemen’s Houthi rebels, was still on fire as recently as Saturday, maritime monitors said.

Threatening an oil spill four times the size of the 1989 Exxon Valdez disaster off Alaska, a leak or on-board blast could cause almost irreparable damage, said Julien Jreissati, Middle East and North Africa program director at Greenpeace.

“Once released, an oil spill of this magnitude could be nearly impossible to contain, spreading contamination across vast areas of seawater and coastlines,” Jreissati told Agence France-Presse.

“The long-term impacts on marine biodiversity could be devastating, with oil residues potentially persisting in the environment for years or even decades.”

The Houthis have been firing drones and missiles at ships in the vital commercial route since November, saying they are targeting vessels linked to Israel, the United States and Britain in a show of solidarity with Palestinians over the Israel-Hamas war in Gaza.

The Sounion, carrying 150,000 tons of crude oil, lost engine power and caught fire after the initial strike, forcing the evacuation of its 25 crew members by a French frigate serving with the European Union’s Aspides force, which is patrolling the area.

The Houthis then returned and detonated charges on the ship’s deck, setting off new fires. It is anchored west of the rebel-held port city of Hodeida, midway between Yemen and Eritrea.