BP, operating with the U.S. Coast Guard and the Minerals Management Service, yesterday conducted a controlled burn on parts of an offshore oil spill in the Gulf of Mexico.

U.S. government officials have revised estimates of the Macondo spill's volume to 5,000 barrels per day, or five times the original figure. The revised spill estimate was made public by the US National Oceanic & Atmospheric Administration (NOAA).

The operator continues to escalate its response plan following the sinking of the Transocean Deepwater Horizon and subsequent release from the Mississippi Canyon 252 well (Macondo).

During a flyover on Tuesday, April 27 at 5:00 p.m. (CST), the Coast Guard identified a rainbow sheen approximately 600 miles in circumference with areas of emulsified crude in the U.S. Gulf of Mexico. The edge of the sheen was approximately 23 miles off the coast of Louisiana. Five staging areas are in place and ready to protect sensitive shorelines.

Improved weather for vessels and aircraft is aiding in the dispersion of the sheen that comprises the vast majority of the spill and is enabling skimming vessels to operate far offshore and aircraft to fly multiple dispersant sorties. Weathering and dispersion tactics are breaking down the oil into a frothy emulsion. Fire boom has also been deployed to contain and burn heavier pockets of oil. The latest response numbers are:

More than 100,000 feet of boom (barrier) has been assigned to contain the spill. An additional 286,760 feet is available and 320,460 feet has been ordered.

To date, the oil spill response team has recovered 16,311 barrels (685,062 gallons) of an oil-water mix. Vessels are in place and continuing recovery operations.

69 response vessels are being used including skimmers, tugs, barges and recovery vessels.

76,104 gallons of dispersant have been deployed and an additional 89,746 gallons are available.

BP is working closely with Gulf Coast state environmental officials to implement an extensive shoreline protection plan. This includes deployment of more than 100,000 feet of boom over the last two days to minimize impact to sensitive areas in the Mississippi River Delta area. Staging areas are also in place and ready to protect sensitive shorelines.

These areas include: Biloxi, Miss., Pensacola, Fla. Venice, La., Pascagoula, Miss., and Theodore, Ala.

BP, as operator of the MC252 lease, continues to work around-the-clock on Transocean's subsea equipment. Remotely-operated vehicles are monitoring the well and riser. Monitoring has detected an additional leak on the riser closer to the well. ROVs also continue to methodically work through procedures aimed at subsea activation of the blow-out preventer on the MC252 well.

In parallel with these offshore efforts, advanced engineering design and fabrication of a subsea oil collection system has started onshore. This will be the first time this proven shallow water technology has been adapted for the deepwater. It is expected to be ready for deployment within the next four weeks.

BP also today began preparations to drill a relief well into the MC252 exploration well following the arrival on site of the Transocean Development Driller III. Drilling plans have been approved by the U.S. Minerals Management Service. A second drilling ship, Transocean's Discoverer Enterprise, is also on its way to the site with plans being developed for a second relief well should it be necessary.

Preliminary estimates indicate that current efforts to contain the spill and secure the well are costing the MC252 owners about $6 million per day. This figure is expected to rise as activity increases. BP has a 65 percent interest in MC252.