The Coast Guard says an oil sheen off Louisiana's coast is breaking up and is much smaller than when it was first spotted.
The sheen initially was reported to be about 10 miles long and a mile wide when it was spotted Wednesday about 130 miles southeast of New Orleans.
No source has been determined for the oil.
A Coast Guard spokesman said Friday that the sheen is dissipating and at last report was about five miles long and about 100 yards wide.
The sheen was in the area of two Shell production platforms, but Royal Dutch Shell says it is confident its operations were not the source.
The Coast Guard said it would have a pollution investigator aboard a Shell flight over the site on Friday.