U.S. Coast Guard photo by Petty Officer 3rd Class Brandyn Hill (Deepwater Horizon Response on Flickr Creative Commons)

BP has successfully stopped the oil flowing out of the ruptured well in the Gulf of Mexico by filling the well with a special kind of mud.

It could be necessary to pump more mud into the well and workers may seal the top with concrete to assist in the proposed lasting solution of the two relief wells currently being drilled.

From a BBC News report:

The US government says the well leaked 4.9 million barrels of oil before being capped last month, with only 800,000 barrels being captured.

The US government is expected to announce today that the remaining oil in the Gulf poses little threat and that roughly 75% of the oil from the Deepwater Horizon leak has either dispersed, been captured, evaporated or been disposed of by other means.

A government report finds that about 26 percent of the oil released from BP’s runaway well is still in the water or onshore in a form that could, in principle, cause new problems. But most is light sheen at the ocean surface or in a dispersed form below the surface, and federal scientists believe that it is breaking down rapidly in both places.

–New York Times

The head of the National Oceanic and Atmospheric Administration, the main producers of the forthcoming US government report, said however, that the full impact of the spill in the Gulf is not yet known and that they will continue to monitor present and possible future damage, especially concerning the eggs and larvae of sea life like fish, crabs and shrimp.

For more on the story, see this article in the New York Times:

U.S. Finds Most Oil From Spill Poses Little Additional Risk

Another concern in the Gulf is chemical contamination from dispersants used in the cleanup operation. Some US Environmental Protection Agency officials disagreed with the EPA’s approval of BP using such chemical dispersants, but their warnings were unheeded.

Jeff Ruch, the executive director of the whistleblower support group Public Employees for Environmental Responsibility, said he had heard from five scientists and two other officials who had expressed concerns to their superiors about the use of dispersants.

–Guardian

Some studies have shown oil mixed with dispersants to be more toxic than oil on its own.

Read more on the story in the following Guardian article:

BP oil spill: Obama administration’s scientists admit alarm over chemicals

Additional resources:

New York Times – ‘Static Kill’ Appears to Be Working in Well, BP Says