In the Gulf, struggling with the oil disaster (photos)

In September, Deepwater Horizon, an oil rig owned by Transocean and leased to BP, drilled the deepest oil well in history at a vertical depth of 35,050 feet. On April 20, an explosion left 11 crew members dead and unleashed a torrent of oil into the Gulf of Mexico that has since added up to many millions of gallons.

Since the explosion, BP and U.S. government agencies been struggling to contain and clean up the massive flow. Meanwhile, oil continues to gush. It has already devastated stretches of the Louisiana coast, threatening wildlife and livelihoods.

On Friday, BP CEO Tony Hayward acknowledged in an interview with CNN that the situation has become an "environmental crisis and catastrophe." Also on Friday, the company said that it is continuing with its "top kill" effort to try to stem the flow of oil, and Hayward said, "I think it's probably 48 hours before we'll have a conclusive view of this."

In this slideshow, CNET takes a look at efforts over the past five weeks to contain the disaster. In addition to the overall work to stop the flow itself, other efforts have included burning off oil, using chemical dispersants, and building booms and levees.

Here is an aerial image of oil on the Gulf's surface, taken from a U.S. Coast Guard aircraft in early May.

On Thursday, the U.S. Geological Survey estimated the well has spewed about 500,000 to 1 million gallons each day--greater than a previous estimate of 210,000 gallons a day.

If the estimates are accurate, even the most conservative figures would mean this disaster is worse than the 1989 Exxon Valdez spill in Alaska. The Valdez spilled 11 million gallons into Prince William Sound.

BP said Friday that it now estimates the total cost of the response to the Deepwater Horizon disaster at $930 million.

On May 5, a containment cofferdam is hoisted onto the deck of a ship, but efforts to use that containment method proved a failure.

On May 11, a containment chamber known as a "top hat" was loaded onto a ship's deck.

The unit was lowered onto the sea floor near the flow, and undersea robots positioned the cap over the flow. This effort failed too.

Remotely operated vehicles monitored and recorded the attempt to cover the well. The video display shows the "top hat" being lowered into the Gulf of Mexico on May 11.

In the meantime, other efforts to deal with the flow have been tried, such as burning oil off the water's surface.

Dark clouds of smoke fill the sky as oil burns during a controlled fire in the Gulf of Mexico.

Jeff Cantrell, vice president of Elastec/American Marine, relays information during a controlled burn.

In a process known as flaring, oil from the Deepwater Horizon wellhead was burned by the drillship Discoverer Enterprise on May 16.

Traditional booms have been used for at least two purposes during the crisis.

Here, Louisiana oil field diver Adam Shaw uses a hook to separate a more traditional oil boom that was to be used to trap oil for burning.

Booms have also been put in place to try to protect sensitive areas such as Bretan Island, La., which is a nesting ground for endangered birds.

According to the government's official response site, more than 3 million feet of booms had been deployed in the Gulf as of Thursday.

Less-traditional booms have also been deployed.

Here, in Fort Myers, Fla., volunteers stuff hair into nylon stockings to make oil-soaking containment booms.

The less-than-traditional booms use any kind of nylons--including tights, thigh highs, and knee highs--to hold hair, which is highly absorbent.

Volunteers have filled booms in Alabama as well. These were filled at Felix's Fish Camp in Mobile in mid-May.

Last week, the Army National Guard was creating levees across beaches on Elmer's Island, just west of Grand Isle, La.

The levees are designed to help prevent oil from from reaching sensitive wetland habitats.

Yet another way of trying to manage the flood of oil has been the use of chemical dispersants.

This image from BP shows how the chemical dispersant Corexit is being used to deal with the oil before it reaches the surface.

Hundreds of thousands of gallons of dispersant have been applied to the spill so far--an amount far greater than ever before used in U.S. waters.

Earlier this week the Environmental Protection Agency asked BP to curtail its use of Corexit over concerns about its effects on marine life. BP and the EPA have been arguing over the use of the dispersant. The agency is looking into whether there are less toxic alternatives available in large enough quantities.

Preparing to spray the chemical dispersant Corexit from the air, U.S. Air Force Master Sgt. Brad Franken prepares a C-130 spray operating loadmaster from the 910th Airlift Wing at Youngstown-Warren Air Reserve Station in Ohio.

Members of the 910th Airlift Wing are in Mississippi to assist with the response to the Deepwater Horizon oil spill. The 910th AW specializes in aerial spray and is the Department of Defense's only large area fixed-wing aerial spray unit.

A U.S. Air Force chemical-dispersing C-130 aircraft drops Corexit into the Gulf of Mexico.

In yet another effort to help deal with the crisis, the National Ocean and Atmospheric Administration has been providing coordinated scientific weather and biological response services to federal, state, and local organizations.

Here, Nick Shay, professor of meteorology and physical oceanography at the University of Miami, and Bill Olney, a flight electronics technician, prepare to deploy an air-launched probe from a NOAA plane last week to study the Gulf of Mexico Loop Current and how best to prepare for the oil's movements.

Some of the most tangible evidence of the oil spill's effect have been on the local wildlife population. Here, members of the Louisiana State Wildlife Response Team work to cleanse oil from a pelican.

On the beaches, containment efforts continue with gear including water-filled tiger dams such as this one being set up by National Guard members on the Gulf side of the Southwest Pass of the Mississippi Delta.

Teams made up of representatives from the Coast Guard, the state of Louisiana, and workers contracted by BP are now faced with cleaning up oil that is washing up along scores of miles of the Louisiana coast and beyond.

Cleanup of oil-contaminated sand, as here at Grand Isle, La., is often a very low-tech operation.

A member of a Shoreline Cleanup and Assessment Team walks along an oil-soaked beach in Port Fourchon, La. The big question for everyone: how long will this go on?