Oil companies trade blame over Gulf of Mexico spill

Oil industry titans faced off on the first day of congressional hearings into the April 20 explosion on the Deepwater Horizon rig, which killed 11 workers and led to one of the worst oil spills in American history.

Democratic Senator Jeff Bingaman, leading the hearing, blamed "a cascade of failures" but warned against making "snap judgments" like banning all offshore drilling.

In prepared testimony, operator BP said rig owner Transocean was responsible for the failure of the giant blowout preventer valve which made it impossible to regain control of the well.

But Transocean, the world's largest offshore drilling contractor, said blaming them "simply makes no sense," with firm chief Steven Newman stressing "all offshore oil and gas production projects begin and end with the operator."

Newman also pointed the finger at Halliburton, saying the oil services company was responsible for vital cement work around the wellhead, which should have sealed the exploratory well until full production began.

Moments before the Energy and Natural Resources Committee hearing began, demonstrators took aim at BP, some with black teardrops painted on their faces in quiet protest, others calling out "BP kills wildlife, BP kills people, BP kills the planet."

Although it has not admitted being at fault, the British energy giant has accepted responsibility for the clear-up and is leading frantic efforts to stop an estimated 210,000 gallons of oil from spewing into the sea each day.

It lowered a giant dome over the main leak on Friday but by Sunday this had become clogged with ice crystals and was unable to function as intended as a funnel to divert the leaking oil up to a waiting tanker on the surface.

BP plans to make a second attempt this week with a smaller version, dubbed the "top hat," which it will lower onto the ruptured pipe nearly a mile (1,500 meters) down on the seabed.

BP began drilling a relief well on May 2 that could divert the flow until the well is permanently sealed, but this may not be ready until August so engineers are furiously searching for alternatives.

The company is even contemplating a bizarre operation to inject golf balls, tires and other "junk" into the main leak, and then jam it up.

The "junk shot" would be risky as experts have warned that tinkering with the blowout preventer could see crude shoot out unchecked at 12 times the current rate.

As efforts to contain the leak grow more desperate, an oil slick the size of a small country has developed off Louisiana, sending large expanses of sheen near vital shipping lanes and encircling ecologically fragile nature reserves.

Louisisana's 2.4 billion dollar fishing industry is already being hit by a partial ban and animals are at risk in a region that is a major migratory spot for rare birds and contains vital spawning grounds for fish, shrimp and crabs.

President Barack Obama has dispatched a fresh delegation of officials led by Energy Secretary Steven Chu to meet BP representatives in Houston, Texas and make sure they are doing everything they can to find potential solutions.

Obama has requested legislation be sent to Congress to reform existing laws so they cap damages linked to oil spills in the billions rather than in the millions of dollars.

Lisa Jackson, Obama's head of the Environmental Protection Agency, warned Tuesday the scale of the disaster was unprecedented, telling CNN the spill "has the potential to be worse than anything we've seen."

Hayward admitted in an interview with NPR radio it was "certainly possible" the well could go uncontained for months, a scenario that could see it the amount of oil leaked double the amount involved in Alaska's 1989 Exxon Valdez disaster.

Two days of public investigative hearings into the rig explosion and growing oil spill meanwhile got under Tuesday in a suburban New Orleans hotel.

The probe co-chaired by the US Coast Guard and the US government's Minerals Management Service, began with a moment of silence for the 11 dead workers.

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