The U.S. government is expected to announce that three-quarters of the oil from the BP Plc spill in the Gulf of Mexico has already evaporated, dispersed, or been captured or eliminated, The New York Times reported on Wednesday.
A government report, due to be unveiled on Wednesday morning was also expected to say that what is left of the oil is so diluted that it does not seem to pose much additional risk, the newspaper said.
The report found that about 26 percent of the oil released in the world's worst accidental marine oil spill was still in the water or onshore in a form that possibly could cause new problems.
But most is light sheen at the surface or dispersed below the surface and federal scientists believe that it is breaking down rapidly, The New York Times reported.
The report, by federal scientists with outside help, is the result of an effort to determine the total volume of oil released and to figure out where it went, the newspaper said. The National Oceanic and Atmospheric Administration was the lead agency on the report, the newspaper said.
On Monday, government scientists released revised figures showing almost 5 million barrels of oil leaked in the spill triggered in April by a deadly rig explosion at the BP-owned Macondo well.
The well was temporarily capped on July 15 and on Tuesday BP pumped heavy drilling mud into the well in a "static kill" operation it hopes will help permanently plug the well.
The National Wildlife Federation released a letter from nine scientists and marine researchers concerned over reports that BP was requiring confidentiality clauses in research contracts with scientists, which would prevent them from releasing findings for three years.
The letter, sent to U.S. Attorney General Eric Holder and incoming BP CEO Robert Dudley, demanded full public disclosure of all scientific data related to the disaster .