The likelihood of Bermuda being affected by the giant oil slick in the Gulf of Mexico is "very high", the Ministry of Environment warned last night.

But senior scientist Anthony Knap, president and director of Bermuda Institute for Ocean Sciences (BIOS), told The Royal Gazette the worst the Island could probably expect was tar balls.

"As far as oil slick heading Bermuda's way, I think that's inconceivable," he said. "By the time it reached us, it would certainly not be a coherent oil spill. It would be lumps of tar."

An estimated 1.6 million gallons of oil are reported to have leaked from a BP rig in the Gulf — thousands of kilometres from Bermuda — since an explosion on April 20 which killed 11 workers.

US President Barack Obama has warned of a "potentially unprecedented environmental disaster" along the coast of Louisiana, Mississippi, Alabama and Florida.

A Bermuda Ministry of Environment spokesman said yesterday: "The information we are receiving would suggest that the likelihood of some eventual impact is very high.

"It's believed to be only a matter of time before the oil slick reaches the Atlantic coast of Florida and, once that happens, it will move through this region of the Atlantic on the Gulf Stream and its eddies.

"Even less predictable at this time is what form any infiltration of oil residues into this region of the Atlantic Ocean will take, but tar balls on the beach are a possibility.

"As oil weathers over time, a floating residue of waxy lumps, also known as tar, are left behind. Tar balls were a frequent sight on Bermuda's beaches well into the 1980s."

The spokesman said the Island's Oil Pollution Response Team had not yet been put on alert but the Ministry was monitoring the situation daily.

Dr. Knap, an oil pollution expert who has written more than 30 papers on the topic, said: "We have always had tar, which is oil residue, washed up on the beaches of Bermuda because we are on the edge of the Sargasso Sea and, as a result, currents bring things our way.

"But what would happen is, if it did get into the current and squirted out into the Gulf Stream, it would be dispersed by the Gulf Stream to the north of us."

He said the oil would have broken up into little balls of tar by the time it got near to Bermuda and was unlikely to have any significant impact on the Island.

"It could add to the total amount of tar in the North Atlantic," he said. "But it wouldn't be this gooey spill that would come towards Bermuda. It's a hell of a long way away. It's a pretty big ocean. It means the chances of it having a major impact on Bermuda are very small."

He said BIOS advocated dispersing the oil with chemical dispersants. "It's the most effective way to deal with oil spills in the open ocean. There are trade-offs in doing that. You affect the fisheries and things that live in the sea."

Dr. Knap said people probably need not worry about the oil affecting Bermuda's endangered cahow, as the bird lives in the open oceans far south of the Island and any oil residue would be driven north.