Massive oil spill imperils Gulf Coast (images)

On April 20, the Deepwater Horizon, a semi-submersible offshore drilling rig operated by BP and located in the Gulf of Mexico close to the Louisiana shore, exploded. Two days later, it sank. At least 11 workers were killed in the accident.

The explosion, fire, and subsequent sinking has resulted in a massive, and still continuing, oil spill and slick that is threatening the coast line throughout the Gulf region states of Louisiana, Mississippi, Alabama, and Florida.

Now, as emergency response teams from a wide range of agencies try to plug the leak, which is said to be located at 5,000 feet below the surface, there is no known method for ceasing the oil spill or for fully containing the slick. Many people expect an ecological catastrophe along the coast and in the region of the spill, even as many methods are being used to contain the spill.

Here, the oil slick is seen near what is called Mississippi Canyon during an overflight by the National Oceanic and Atmospheric Administration on Monday. The slick has continued to spread and grow since then. Some say it could be weeks before the oil stops spilling into the Gulf.

Fire crews battle the ranging blaze on the Deepwater Horizon on April 21 the day after the semi-submersible offshore oil rig exploded.

A close-up image of the oil slick as seen on Thursday. Appearing as interlocking comma-like shapes--one almost transparent and one opaque--the oil slick comes close to touching the Mississippi Delta. The slick is made highly visible because of the reflection of the sun on the water.

The close-up of the oil slick seen in the previous image is taken from this wider-area satellite image of the Gulf Coast region.

A graphic depicting the location--as of Wednesday--of the giant oil slick produced by the spill from the now-sunk Deepwater Horizon.

Based on weather and wind forecasts made on Wednesday, this image depicts the predicted spread of oil slick by Friday. As seen here, it is expected that the oil will reach the coast by Friday, likely at the mouth of the Mississippi River. Such an occurrence could create a severe environmental hazard.

This image of the Gulf Coast and the oil spill, taken on Sunday by NASA's Aqua satellite and using its Moderate Resolution Imaging Spectroradiometer (MODIS) instrument, shows the Mississippi Delta on the left and the wide oil slick to the right.

A file photograph of the Deepwater Horizon, which was located about 50 miles off the southeast coast of Louisiana.

A close-up of the oil slick, as seen on Sunday. At least 42,000 gallons of oil are spilling into the Gulf every day.

An aerial image of U.S. Coast Guard skimming operations in the aftermath of the Deepwater Horizon disaster in the Gulf of Mexico.

During the aftermath of the Deepwater Horizon accident, crews above the surface sent a remotely-operated vehicle (ROV) down to where the semi-submersible offshore oil rig's "blowout preventer" was located. The ROV has a robotic arm, which is seen here, trying to activate the blowout preventer.

In this Coast Guard image, the U.S. Environmental Services' Preston Kott drives oil absorbent boom into a pollution control staging area at a warehouse in Venice, La., on Tuesday. Along with this one, staging areas have been set up all along the Gulf Coast in attempt to "actively identify, target and protect environmentally and economically sensitive areas," according to the Coast Guard.

The Deepwater Horizon's blowout preventer, which crews hoped could be activated by the robotic arm of a remotely-operated vehicle to cut off the flow of oil.

The oil slick, as seen on Tuesday.

A pollution containment chamber is moved into position at Wild Well Control in Port Fourchon, La., on Monday. The chamber is thought to be one of the biggest yet built and is planned for use in attempt to contain the oil spilling from the Deepwater Horizon.