Some good news from the Gulf of Mexico, where BP has managed to shut off one of the three leaks from which oil is seeping out into the ocean.

There are still two points on the sea floor from which crude is leaking and forming the gigantic slick that threatens wildlife in the Gulf. This follows an accident aboard the Deepwater Horizon which caused the drilling rig to sink with the loss of 11 lives on 22 April.

Although the rate of leakage – estimated at 5,000 barrels a day – is likely to be unchanged following this development, it should make the job of dealing with the problem a bit easier, says BP.

The oil company also began moving a newly fabricated ‘containment dome’ to the accident site. It plans to lower this down to the seabed to catch oil for pumping to the surface, where it can be collected.

Yesterday the response teams conducted another controlled burn to remove oil on the surface (image right).

In other news, the Financial Times reports that the spill might be “the final nail in the coffin for the Obama administration’s climate change bill” as Democrats are increasingly unwilling to back the bill, due to the provisions it contains to expand offshore drilling.

There’s also an increasing focus on the dispersant chemicals which are being used to break up the oil. The Guardian says that “scientists fear [they] can cause genetic mutations and cancer”. The NY Times says the clean up crews are now “engaging in one of the largest and most aggressive experiments with chemical dispersants in the history of the country, and perhaps the world”.

“It’s basically a giant experiment," Richard Charter, of the Defenders of Wildlife group, agreed (AP). “I’m not saying we shouldn’t do it; we have no good options.”

Wired questions the decision to use the Corexit 9500 dispersant rather than the supposedly better Dispersit.

Meanwhile, ProPublica reports that the regulator of offshore drilling in the US “understated [the] risks of oil spills in plans to expand drilling” and that “congressmen raised concerns” about BP’s safety record before the Gulf oil spill.