A massive oil spill in the Gulf of Mexico is spewing 159,000 litres of crude oil a day into the sea.
Crews are drilling in the Gulf of Mexico to reduce the pressure from a blown-out oil well off the Louisiana coast that is causing a potential environmental disaster.

An aerial photo taken near the coast of Louisiana shows some of the oil that's leaked from a pipeline since last week's explosion and collapse of the Deepwater Horizon oil rig. (Gerald Herbert/Associated Press) 

An offshore oil rig, the Deepwater Horizon, exploded last week, triggering the spill. It could take up to three months to drill a relief well from another rig brought to the site where the Deepwater Horizon sank after the blast.

49 vessels, including tugboats, barges and special recovery boats are currently working on containing the spill. Containment boom is being used to reduce the spread and oil skimmers that separate oil from water are being used to remove the oil from the water surface.

Efforts are being made to shut off the well but if it cannot be closed, almost 100,000 barrels, or 15.9 million litres, of oil could spill before the relief well gets up and running. The worst oil spill in U.S. history occurred when the Exxon Valdez spilled 41.6 million litres in Alaska's Prince William Sound in 1989.

One of the major concerns for authorities now is containing the spill, which threatens to coat marine mammals and birds with oily slime and taint hundreds of kilometres of white-sand beaches and rich seafood grounds.

Though oil is not expected to reach the coast until late in the week, if at all, concern has been growing about what will happen if it does.

In Gulfport, Mississippi where white sand beaches are a tourist playground and dolphins, whales and manatees are frequent visitors to Mississippi Sound, residents are bracing for the worst. The advancing spill is seen by locals as a threat to everything important in their region. It could wipe out the oyster industry, shrimping may not recover for years and tourism will be significantly affected.