BP begins final countdown to 'static kill'; well could be sealed by Wednesday

BP prepared Tuesday to plug the worst oil leak in history, although the Gulf of Mexico region will be counting the environmental and economic costs for years, perhaps decades, to come.

Already delayed by a week due to Tropical Storm Bonnie, the long-awaited "static kill" was put off again at the last-minute when a leak was discovered on Monday in the cap that has been sealing the runaway well since July 15.

US spill chief Thad Allen said the leak had been stopped overnight and that the operation to ram in heavy drilling fluids, known as mud, would commence as soon as "injectivity tests" had given the procedure the all-clear.

"We have pump rates and we have pressure. That will then provide the basis for a decision to proceed to the static kill later on today," Allen said.

The hope is that injections of mud through the blowout preventer valve on top of the well will force the oil back down the reservoir, allowing concrete to be pumped in to seal it once and for all.

BP's now notorious Macondo well could be permanently out of action by Wednesday, although a "bottom kill" will be performed through a relief well mid-August to cement in the outer well bore and make sure of success.

The extent of the spill was confirmed on Monday as US government experts announced the rate the oil had been pouring out was 62,000 barrels a day -- more than 12 times faster than BP originally admitted.

This was higher than any previous official estimate and meant 4.9 million barrels of crude -- more than 205 million gallons -- had spewed into the Gulf in the 87 days it took to cap it, making it the biggest accident spill ever.

If BP is found guilty of negligence, the flow rate means it could face up to 17.6 billion dollars in fines. The firm has also set up a 20 billion dollar fund to pay claims from individuals and businesses hit by the disaster.

Shutting the well will bring some relief to coastal residents who have faced uncertainty and frustration in equal measure since the BP-leased Deepwater Horizon rig exploded in April and sank to the bottom of the Gulf.

But the full extent of the economic costs and environmental harm will not be clearly known for some time and a study Tuesday showed the impact is already starting to tell.

Of 1,200 coastal Gulf coast residents surveyed by researchers at the National Center for Disaster Preparedness (NCDP) at Columbia University last month, 40 percent said they had been directly exposed to the spill, a third said it had affected their kids, and 20 percent said it had hit their wallets.

Parents reported that their children had developed mental, behavioral or physical problems -- everything from respiratory problems and rashes to feelings of sadness or nervousness, difficulty socializing with other children, or trouble getting to sleep.

One in five residents told the Columbia researchers that their household income had fallen, with poor residents -- those who earned less than 25,000 dollars a year -- feeling the pinch more than the better-off.

While there is hope that Louisiana's marshes and fragile wetlands may recover relatively quickly, this is a spill of unprecedented size at an unprecedented depth and no one knows the real impact on the Gulf food chain.

Fishermen, who don't know when they will be able to fish again, if the fish will still be there, or if they will be safe to eat, are likely to lose their BP clean-up jobs in the coming weeks as the surface oil is all mopped up.

Oil workers face lay-offs due to President Barack Obama's moratorium on new deep sea drilling permits, and tourists are likely to give the coastal region a miss for several years to come.

BP, which replaced its under fire British chief executive Tony Hayward last week with American Bob Dudley, also faces a rocky road to recovery and has already agreed to sell off key assets.

The company last week posted a quarterly loss of 16.9 billion dollars and set aside 32.2 billion dollars to pay spill costs.