To the Gulf of Mexico now where efforts are continuing to protect vulnerable wetlands from a rapidly approaching oil slick. So far, an estimated four million gallons of oil has leaked from BP's damaged rig. And the parties involved in the disaster are all blaming each other.

 

Black Hawk helicopters help to line Louisiana's barrier islands with one-ton sand bags to bolster protection of the state's crucial wetlands.

Authorities also plan to use South Louisiana's system of locks and levees to release water and help keep most of the oil at sea.

BP engineers are continuing to try and stop the oil flow by using a giant containment dome over the top of the leak. They're also using small golf-balled sized pieces as a plug.

The device is expected to be in place by the end of the week.

Oil executives will now face intense questioning before two Senate committees.

Based on written testimony, the executives will blame each other's companies for the rig explosion and failure to control the oil slick.

Transocean's prepared testimony for the hearings blames the explosion on the failure to cement a plug to the underwater well.