The Great Gulf of Mexico Oil Spewage Thread

The leak itself is far from over. With up to 40 million gallons of oil now in the sea, efforts to plug the hole (disgorging up to 19,000 barrels a day) have become frantic. Since Wednesday, BP has been trying to block the source by blasting it with mud and concrete. On Friday, things took a more desperate turn as BP added a dubious-sounding "junk shot" of shredded rubber and golf balls. BP's chief operating officer, Doug Suttles, said yesterday: "To date it hasn't yet stopped the flow. What I don't know is whether it ultimately will or not."

"It's the biggest environmental disaster of our time and it's not even over yet," said the marine toxicologist Dr Susan Shaw, director of the Marine Environmental Research Institute based in Maine. She has been diving among the damage and is horrified by the contamination caused by BP's continued use of dispersants. "They've been used at such a high volume that it's unprecedented. The worst of these – Corexit 9527 – is the one they've been using most. That ruptures red blood cells and causes fish to bleed. With 800,000 gallons of this, we can only imagine the death that will be caused."

According to Dr Shaw, plankton and smaller shrimps coated in these toxic chemicals will be eaten by larger fish, passing the deadly mix up the food chain. "This is dismantling the food web, piece by piece," she said. "We'll see dead bodies soon. Sharks, dolphins, sea turtles, whales: the impact on predators will be seen in a short time because the food web will be impacted from the bottom up."

The largest of the clouds, confirmed by a University of South Florida research ship last week, has gone deeper than the spill itself, defying BP's assurances that all oil would rise to the surface. It is now headed north-east of the rig, towards the DeSoto Canyon. This underwater trench could channel the noxious soup along the Florida coast, impacting on fisheries and coating 100-year-old coral forests. Tests on the toxicity of another chemical cloud, some 10 miles long and heading south-west of the site, are also being done by scientists from the University of Georgia.