Scientists and state officials are watching closely as crews try to stop the gusher that is leaking oil into the Gulf of Mexico and trying to assess whether any oil from the spill could reach Maine’s coastline.

• BP restarts top kill pumping after suspension
• Gulf of Mexico leak worse than Exxon Valdez spill
• Obama says: 'I take responsibility' for clean-up
• Head of the US minerals management service resigns

All Thursday's live updates as they happened

10.40am:

BP began pumping mud into the Macondo well at 7pm BST yesterday – a procedure (slightly) more technically known as 'top kill'.

This morning the oil company said things are going to plan with the latest attempt to stem the oil flow, or at least did not announce that anything is going wrong:

'Top kill' operations continued over the night and are ongoing. There are no significant events to report at this time. BP will provide updates on progress as appropriate.

In addition to watching the progress of the top kill, it will be interesting to see how the markets react to the announcement from the Obama administration that proposed exploratory drilling in the Arctic Ocean will be suspended until 2011 – potentially disrupting Shell Oil's plans to begin drilling five exploratory wells this summer.

Yesterday Barack Obama described the disaster as "heartbreaking" while BP chief executive Tony Hayward went for the phrase "absolutely gutted", in an apparent contest to see who was the most concerned as opinion polls suggest large parts of the US public are dissatisfied with both men.

Follow updates on the top kill, and get all your oil spill news here.

11.05am:

This interactive graphic by my colleague Paddy Allen show how the top kill should work.

BP's live feed of the oil leak doesn't appear to be working, but some other sites have video streams that I've had more luck with so far this morning.

The oil company does warn that the stream "may freeze or be unavailable from time to time", but other sites were running the footage not so long ago when BP was down – PBS news's footage was working well earlier, although it seems to have stalled now.

I'll keep looking for reliable streaming of the oil – BP said that throughout the top kill procedure "very significant changes in the appearance of the flows at the seabed may be expected", which could be exciting.

(Although it did add, disappointingly, that: "These will not provide a reliable indicator of the overall progress, or success or failure, of the top kill operation as a whole.")

11.30am:

The top kill has worked above ground but has never before been tried 5,000 feet beneath the sea. (Keen followers of the Gulf oil spill so far will recall that the same applies to every technique – and let's face it, there have been many – that BP has employed so far, as there have never been an oil leak this far beneath the surface before).

BP has rated the latest attempt's chance of success at 60 to 70 percent.

"The absence of any news is good news," said Coast Guard Admiral Thad Allen, who's overseeing the operation.

"It's a wait and see game here right now, so far nothing unfavorable."

Incidentally, the engineers working to stop the spill have come up with some ingenious names for their efforts so far. From introducing the word 'cofferdam' to a wider audience, to reinventing the top hat as a (failed) device to capture the oil, to the brilliantly named "junk shot", the terms for BP's attempts have never failed to capture the imagination.

Yesterday my colleague as conjuring up "a new TV series starring Jeremy Clarkson testing firearms", and 'top kill' is definitely my
favourite so far, although to me it sounds more like a Jean Claude Van Damme film.

.
.
What does the term mean to you? Comment below or email adam.gabbatt@guardian.co.uk if you're shy.

.

11.44am:

The second I start whinging in the comments section, the second the video starts streaming again – at least it is on PBS Newshour's web site.

12.21pm:

Hank Stuever, from the Washington Post, has been watching the live coverage of the oil spill too. He's not overly enamoured with it:

Spillcam combines the dread of horror films with the monotony of Andy Warhol's eight-hour silent movie of the Empire State Building. There is no sound and nothing happens, except the inexorable, unending flow. You watch a little, and then a little more, and then you can't stop watching as a steady plume of dark brown oil belches upward from the floodlit, rocky ocean floor.

12.35pm:

Paul Pemberton emails to recommend the 'Simultaneous Operations Overview - Subsea Operations' section of the BP web site, which is much more interesting than it sounds.

The site has lots of graphics showing the different types of equipment being used in both the top kill attempt and the wider clean up operation.

This image showing the vessels in action on the surface is a helpful source.

12.58pm:

The Los Angeles Times is reporting that President Obama will announce today he'll extend a moratorium on new deepwater drilling for six months in the wake of the Deepwater Horizon disaster.

This is more information coming out about the month long review the US interior ministry has just conducted into oil drilling. The Obama administration is also suspending proposed exploratory drilling in the Arctic Ocean following the report from interior secretary Ken Salazer.

Elsewhere Newsweek has an interesting article on which of the people most often quoted on the Gulf oil spill you can trust.

They've assessed the trustworthiness of interior secretary Ken Salazar, Louisiana governor Bobby Jindal and BP's Doug Suttles, among many others, with lots of links to examples of experts telling, or manipulating, the truth.

1.50pm:
This is Matthew Weaver taking over from Adam Gabbatt. BP's reputation is taking a massive kicking online. BP bashing on Twitter is being led by the spoof account @BPGlobalPR. It features links to T-shirts bearing a smudged-oil logo "BP cares". The same ironic term is also trending on the network at #BPcares.

Over on Facebook almost 150,000 users have expressed support for a group called BoycottBP.

2.22pm:
Top Kill has succeeded in blocking the leak, according to the LA Times citing a coast guard official Thad Allen.

The live feed still appears to show oil spewing from the sea bed, and the latest from BP is that there is nothing to report.

But the LA Times says:

The "top kill" effort, launched Wednesday afternoon by industry and government engineers, has pumped enough drilling fluid to block all oil and gas from the well, Allen said. The pressure from the well is very low, but persists, he said.

2.34pm:
BP's share price has increased by almost 6% on the news of Top Kill's apparent success, according to my colleagues on the business desk.

The US Geological Survey is due to hold a conference call with reporters at 3pm. Our US business correspondent Andrew Clark is due to take part.

The LA Times reporter, Jim Tankersley, who broke the story about about Top Kill succeeding, has back tracked slightly.

He tweeted: "To be clear: #topkill is not yet a success. Oil and gas flow have stopped. Small pressure persists. Cementing still to come. #oilspill."

2.43pm:
The New Orleans news site Nola.com is not getting quite as excited by Thad Allen comments, as the LA Times.

It reports:

An attempt to kill the runaway deepwater horizon well spilling oil into the Gulf of Mexico is going according to plan so far, leaving the coast guard admiral in charge of managing the spill "cautiously optimistic" but unwilling to say the well is capped.

2.55pm (8.55am CDT):
The LA Times has re written its Top Kill "success story" with the following clarification.

An earlier version of this story termed the effort "successful." Officials clarified that neither government nor BP officials had declared the effort a success yet. They caution that only after the cementing is complete and the well is sealed can the top kill be called successful.

3pm:

Here's a sumnmary of the main points so far:

• Reports say that the 'top kill' operation is going to plan and has stopped the flow of oil from the spill. Earlier reports that it had succeeded have not been confirmed by BP or government officials
• BP's share price has increased
• President Obama has extended a moratorium on new deepwater drilling for six months. The president is due to give a press briefing at the White House later.

3.20pm (9.20am CDT)
News is emerging on Twitter about what is being said at US Geological Survey (USGS) conference call.

Kate Sheppard, environmental reporter from Mother Jones, is providing a running commentary.

Flow rate call with USGS. Dr. Marcia McNutt, chair of flow rate technical group, talking to reporters.

McNutt says numbers didn't matter in response, which has "been based on a worst-case, catastrophic scenario."

Surface observations indicate 130k-270k barrels as of May 17, estimates that equal amount burned, dispersed, etc.

One of the teams evaluating flow says could be as high as 25,000 barrels, which would be 5x the previously accepted figures from NOAA/BP.

McNutt says that reasonable lower figure is 11,000 barrels per day, which is already more than twice as much as # given by NOAA, BP so far.

Team looking at satellite info estimates 12,000-19,000 per day flow from well. #BPspill 4 minutes ago via web

A Twitter stream from the Phoenix Sun also has a commentary on the call.

3.23pm (9.23am CDT):
Andrew Clark, who has also been listening to the USGS conference call, has this:

Marcia McNutt, director of US Geological Survey (and scientific adviser to interior sec Ken Salazar), has been giving figures suggesting flow of oil from the leak has been much higher than BP estimated.

According to three different scientific measurement methods, the leak has been flowing at minimum of 12,000 barrels per day, and it could be as much as 19,000 barrels. That's way above BP's estimate of 5,000 barrels.

As of May 17, a Nasa imaging plane found 130,000 to 270,000 barrels of oil on the surface of Gulf. Roughly the same volume again had already been burned, skimmed, dispersed or evaporated.

"This is obviously a very, very significant environmental disaster," McNutt said.

3.35pm (9.35am CDT):
Just to be clear: the USGS did not comment on the top kill operation, it was discussing the damage so far.

But Thad Allen, the US coast guard official, has been discussing top kill. He told the radio station NPR that it was too early to say whether it had succeeded:

"Over the course of the last 12 to 18 hours, they have been able to force mud down and not allow any hydrocarbons to come back up,"

"It's a matter of put some mud down, take some pressure readings, put some mud down, take more pressure readings. One thing they don't want to do is put so much mud down that there may be a structural problem for the well-bore casing and potentially rupture them, which would be something we wouldn't want to have happen."

3.43pm (9.43am CDT):
The head of the troubled US Minerals Management Service, Elizabeth Birnbaum, has been sacked.

The agency was heavily criticised over the leak. An official report found that it allowed staff at oil and gas firms to fill in inspection reports in pencil, with regulators later going over the answers in ink.

3.51pm (9.51am CDT):
The leak could have been five times worse than BP estimates, according to another disturbing update from the USGS. Andrew Clark writes:

To clarify further, the government had three measurement methods. All three agreed the spill has been at least 12,000 barrels per day. Two of them said an upper limit 19,000 per day. The third put the upper limit at 25,000 barrels per day, which would be five times what we were previously told both by the administration and by BP.

3.56pm (9.56am CDT):
Better news from Andrew Clark on top kill:

I've been talking to David Summers, a professor of mining engineering at Missouri University of Science and Technology, who has been following the operation closely.

He says that about seven hours after beginning the "top kill" attempt yesterday, BP was able to drop the pressure of mud being pumped into the well - which was a good sign.

"That means they had enough pressure to displace the oil from the well into the rock formation," says Summers, so the well now contains a column of BP's drilling mud instead of a spurt of oil.

However, the job isn't quite done yet: "They haven't been able to totally balance the pressure yet. The column of mud in there should be stable enough to stand there by itself. But they're still having to apply a little bit of pressure to keep the column stable. That means they may not have got the mud all the way down the well yet."

Still, Summers reckons it's going as well as can be expected and based on what he's seeing, he's optimistic: "The whole thing could be sealed and capped by this time tomorrow."

4.21pm (10.21am CDT):
This is Richard Adams in the Guardian's Washington office, taking over from Matt Weaver for the rest of the day.

10.38am CDT: It's a stinking hot day here in Washington, and the White House press corp is already assembled outside in the blazing sun waiting for President Obama's press conference to start at 12.45pm ET.

More bad news: the Deepwater Horizon spill is officially larger than the Exxon Valdez spill in Alaska back in 1989, making it now the worst oil spill in US history by some distance depending on which estimate you prefer.

Here's the AP description:

Even using the most conservative estimate, that means the leak has grown to nearly 19m gallons, surpassing the size of the 1989 Exxon Valdez disaster, which at about 11m gallons had been the nation's worst spill. Under the highest estimate, nearly 39m gallons may have spilled.

10.43am CDT: More on the Minerals Management Service director Elizabeth Birnbaum, who left her post today after scathing criticism of the agency for its lax work and overly-cozy relationships with the industry it was regulating. Birnbaum has only been in the job since July last year so it seems a little harsh. Ken Salazar, the interior secretary, said that Birnbaum resigned "on her own terms and of her own volition", rather than being sacked. But in such situations there's always a jumped/pushed element.

11.04am CDT: There's a fantastic on-the-ground report from Mac McClelland, a reporter for Mother Jones magazine, who details her run-ins with BP staff and local police in trying to report from the beaches of Louisiana, and what she found there:

The shoreline is packed with men in hats and gumboots and bright blue or white shirts. Nearly all are African-American, all hired from around New Orleans. They tell me they've been standing in these exact same spots for three days. It's breathtakingly hot. They rake the oil and sand into big piles; other workers collect the piles into big plastic bags, and still other workers take them to a plant where the sand is separated out and sent to a hazardous-waste dump and the oil goes on for processing. Then the tide comes in with more oil and everybody starts all over again. Ten dollars an hour. Twelve hours a day.

11.15am CDT: Not so long ago the Republican governor of Louisiana, Bobby Jindal, was telling anyone who would listen that the federal government was too big. For obvious reasons he now takes a rather different view, and will tell anyone who will listen that the federal government just isn't doing enough.

And because of the oil spill he doesn't have enough time to finish writing his biography:

A Jindal spokesman confirmed Tuesday that the governor's upcoming memoir, titled Real Hope, Real Change: New Conservative Solutions to Rescue America, won't be released in July as planned.

Those new conservative solutions to rescue America will just have to wait until the old federal government has rescued America from the oil spill.

11.30pm CDT: The cables are starting to count down the minutes until Obama's press conference in 15 minutes' time. "Arguably the most important if not the most important ever," says CNN's Wolf Blitzer, playing down the whole event.

CNN's John King wants to know why President Obama isn't showing more anger to the public, so maybe at this press conference the president will punch someone from BP to make that point. And why not? (Because violence is never the answer, kids.)

Wolf Blitzer says that he tweeted this morning that Obama was losing the crucial CNN guest commentator demographic, meaning James Carville, the Louisiana native who isn't happy. And if you've lost James Carville, you've lost middle America, right? Sorry, that was Walter Cronkite.

11.50am CDT: Obama's now talking in the East Room, starting with a quick update on the spill and the top kill operation.

"This procedure offers no guarantee of success," warns Obama. On BP, he says: "We will demand they pay every dime for the damage they have done.... Make no mistake, BP is operating at our direction."

"Those who think we were slow in our response or lacked urgency don't know the facts."

11.55pm CDT: Obama's now laying into the "scandalously close relationship between the oil industry and those who were regulating them", and how laws were "tailored by the industry to serve its needs and not the public's."

Obama made official the announcement of action against deep-sea drilling:

• suspend two permits to drill off the coast of Alaska
• cancel oil lease sales off the coast of the Gulf of Mexico and Virginia
• suspend new permits for deep water wells for a further six months
• suspend action of current wells being drilled in the Gulf of Mexico (that is, new wells being drilled, not wells in operation)

12.02pm CDT: CNN is tastefully carrying a small window with the "oil spill cam live" in the bottom righthand corner of the screen, showing oil (or mud, by now, we hope) gushing out while Obama is speaking.

12.07pm CDT: Asked about public concern at BP's continued involvement in the efforts to stop the spill, Obama responds: "This notion, that for the last three or four weeks somehow the federal government is sitting on the sidelines and we've just been letting BP make the decisions, is not true."

Obama says that one of his first questions, during a meeting in the situation room early on in the crisis, was whether the government had the technology to tackle to leak. He was told that it didn't, and that BP had did. "Should the federal government have this technology?" Obama said, and that will be one of the issues that the new panel being set up will consider.

"But for now, BP has the best technology, along with other companies, in capping the well down there."

12.18pm CDT: Chuck Todd of MSNBC asks Obama to address the Katrina comparisons, a very popular topic of conversation on the US right and left.

"I'll leave it to you guys to make these comparisons and make judgments. What I'm spending time thinking about is how we solve the problem," replies Obama, in a lofty tone. "I am confident people are going to look back and say this administration was on top of an unprecedented crisis."

Obama is very much on the defensive here and is lacking fluency in his answers. "I think there was a lack of anticipating what the worst case scenarios would be." No, really?

12.33pm CDT: Oh a question from Helen Thomas, about why America's military is still in Afghanistan. Because she has been in the White House press corp since the Chester Arthur administration, Obama politely responds.

Speaking of which, President Arthur would have done a great job at cleaning up this spill. He certainly cleaned up the US civil service.

Now the New York Times reporter is asking if Elizabeth Birnbaum was fired or sacked or what? "I only found about it this morning," says Obama, "I don't know the circumstances." Mmm.

12.40pm: "You never heard me say, 'drill, baby, drill'," says Obama.

On the live video feed from the well head, a robotic arm has appeared. Exciting? No, it appears to be part of the submarine.

Now there's a question about – really? – Arizona's immigration law and the decision to send 1,200 National Guard members to the border with Mexico. Obama is asked if he is favour of boycotting Arizona (because of its quasi-racist new law which requires the police to ask for immigration status of anyone they suspect of being an illegal immigrant).

"I'm president of the United States, I don't endorse boycotts or not endorse boycotts. That's something that the private citizens can make a decision about," says Obama, sensibly although perhaps a little too even-handedly.

12.47pm CDT: "And it's not just me, by the way. When I woke this morning and I'm shaving and Malia knocks on my bathroom door and she peeks in her head and she says, 'Did you plug the hole yet, Daddy?' Because I think everybody understands that when we are fouling the Earth like this, it has concrete implications not just for this generation, but for future generations," says Obama, now making the case that he is fully engaged on fixing the spill disaster, and so it seems is the rest of his family.

This is from the last question of the press conference, from Major Garrett of Fox News, who asked: "Is your boot on the neck of BP?", employing the metaphor used by interior secretary Ken Salazar.

"I would say we don't need to use language like that, what we need is action to make sure BP is made accountable," replies Obama. "The Gulf is going to be affected in a bad way. So my job right now is to make sure everyone in the Gulf understands, this is what I think about when I wake about in the morning and the last thing at night.

And Obama finishes by saying that he is responsible: "In case you're wondering who's responsible, I take responsibility. It is my job to make sure this thing is shut down."

12.56pm CDT: So the press conference is over, but this wasn't Obama's best effort. "People want a more visceral president," opines John King, a journalist who works for CNN.

Everyone on CNN agrees that because Obama has been in office now for a year and a half (actually, 16 months, but hey) everything is now his fault. Which seems more than fair. By now he should have got around to reading all the drilling licenses and environmental exemptions.

1.09pm CDT: Now the robotic arm appears to be using a spanner on the live video feed from the ROV. It's very cool, although to be honest it's doing a rubbish job.

TV expert thinks that it might be something to do with adding a sensor to measure the temperature. Apparently this is all good news.

(The spanner – or wrench, if you are American – is now just sitting on top of the leak.)

1.15pm CDT: Has the tide turned? It's now 24 hours since the top kill operation began – the initial period that would dictate the success or failure, according to BP – and all the news so far is that it appears to be working.

The colour of the fluid, as seen on the live feed, has certainly lightened since yesterday, and the experts are hailing this as an excellent sign of progress. "The fluid you see right now is almost 100% the fluid that's being pumped down from the surface to create the seal," says Professor Don van Nieuwenhuise from the University of Houston's geo-science programme, on CNN. "From what I can see it's going very well." Van Nieuwenhuise is a veteran of several top kill operations.

When can the cement go in and seal it up? That's the tricky part, the professor says, since it can lead to another rupture.

The New York Times is also cautiously reporting on the success of top kill:

The latest effort to plug a gushing underwater oil well in the Gulf of Mexico appeared to be working, officials and engineers said on Thursday morning, though definitive word on its success was still hours away.
....
But there were indications that the heavy fluid, called mud, was slowly building up within the well bore as it was being pumped from surface ships through pipes on the seafloor. At first, most of the mud was carried away by the oil and gas streaming up through the well at high pressure, but with enough mud being pumped in at a fast enough rate, it started accumulating inside the well as intended. Unless something goes wrong, at some point, enough mud — and thus enough weight — would accumulate to overcome the upward pressure of the escaping oil and gas, and seal the well.

A senior technician working on the measure said on Thursday that the vast amount of data collected so far was positive, and that there was general optimism that it was succeeding. Planning has begun for cementing the well, the next step in sealing it after the flow of oil and gas is stopped by the drilling mud, but that stage would not be undertaken for at least several hours.

Yesterday: The flow on Wednesday afternoon.

Notice how the flow was longer and straighter in the [bottom] image, indicating that it was at higher pressure (velocity) and that now it blows out at much closer distance, meaning it doesn't have the same pressure (velocity).

Today: the flow as seen this morning.

1.45pm CDT: To gauge how the fluid from the leak has changed, here are two screen grabs from today and yesterday, from the excellent site The Oil Drum, which is providing some valuable expert commentary:

Below ... are two pictures to show why I believe that the injection pressure of mud into the well has dropped, indicating that BP have filled the well, and are now holding pressure to see if there are any problems. I would assume, if none develop, that they will inject cement to seal the top of the well, sometime today.

2.35pm CDT: The AP are reporting that seven workers helping to clean up the Gulf oil spill are still in hospital after they reported dizziness, headaches and nausea while working on boats off the Louisiana coast:

West Jefferson Medical Center spokeswoman Taslin Alfonzo said Thursday that doctors believe the likely cause is chemical irritation and dehydration from long hours working in the heat. Alfonzo said the workers told doctors they believe chemicals used to break up the oil made them sick.

Authorities say the workers became ill Wednesday while cleaning up oil in Breton Sound, southeast of New Orleans. Officials ordered all 125 commercial boats working the cleanup there to leave the area.

3.15pm CDT: Oh dear. It appears that some evil hackers managed to briefly hijack the @BP_America official Twitter account.

According to Fox News, at least one rogue tweet was up on the official BP feed for only a brief time before it was caught by an eagle-eyed BP employee (at least they're good at something). The offending tweet read: "Terry is now in charge of operation Top Kill, work will recommence after we find a XXL wetsuit. #bpcares #oilspill".

3.30pm CDT: The Coast Guard is holding a press conference in Venice, Louisiana, saying that mud is still being pumped into the well and "wait and see" is still the order of the day. Admiral Thad Allen says mud is still coming out of the leak, which suggests the pressure still hasn't been contained. "They said this could take 24 to 36 hours, and they are in the process of monitoring it," said Allen, who was more downbeat than his previous appearance this morning.

3.54pm CDT: Vermont's independent Senator Bernie Sanders has a piece on the Gulf oil spill over at Comment Is Free America:

Offshore drilling simply does not achieve the goals that its advocates claim, and it is not worth the risk. If we are serious about wanting to break our dependence on foreign oil and move to energy independence; if we want to lower the cost of energy; if we want to combat climate change and cut greenhouse gas emissions; if we want to create millions of new jobs – then more offshore drilling is not the way to go.

4.02pm CDT: Admiral Thad Allen pops up on MSNBC to be interviewed/shouted at by Chris Matthews. Matthews barks at the admiral to ask if top kill is working. Allen won't be drawn, but does say: "They've successfully done something at 5,000 feet that's never been done before."

On the idea of getting a fleet of supertankers to cruise around sucking up oil from the water's surface, as was done off Saudi Arabia in the 1990s, Adm Allen says there are various problems, such as not having enough room around the Deepwater rig site, but that it's being considered.

4.30pm CDT: Bad news: the New York Times is reporting that the top kill effort has been suspended by BP because too much fluid is still escaping from the leak.

BP had to halt its ambitious effort to plug its stricken oil well in the Gulf of Mexico on Thursday afternoon when engineers saw that too much of the drilling fluid they were injecting into the well was escaping along with the leaking crude oil.

A technician at the BP command center said that pumping of the fluid had to be stopped temporarily while engineers were revising their plans, and that the company hoped to resume pumping by midnight, if federal officials approved.

The technician, who spoke on condition of anonymity because he was not authorized to brief reporters, said the problem was not seen as serious. "We're still quite optimistic," he said, but cautioned: "It is not assured and its not a done deal yet. All of this will require some time."

The NYT is doing some top reporting work on top kill.

5.15pm CDT: The Associated Press is confirming the New York Times story, mentioned below, that BP has suspended top kill operations for the time being:

BP is pausing its unprecedented attempt to plug the Gulf of Mexico oil leak, saying it wants to monitor the effects of the top kill attempt.

BP said Thursday that nothing was going wrong with the procedure that involves force-feeding mud into the blown-out well in an attempt to overcome the oil flowing upward.

BP says it hopes to resume shooting mud into the well Thursday night. Chief Operating Officer Doug Suttles says he is not surprised that it is taking longer than expected.

5.45pm CDT: My excellent colleagues Andrew Clark and Suzanne Goldenberg round up the latest Gulf oil spill news, including this dire warning:

Scientists warned there was potential for even greater damage with a forecast of an unusually hazardous hurricane season. The national weather service in its yearly forecast for the hurricane season starting 1 June predicted between eight to 14 hurricanes across the Atlantic. Of those, three to seven could be major hurricanes, category three storms or higher. Hurricane Katrina was a category three.

Amid all the talk of technology and top kills, it's easy to overlook the risks that remain, and how the people and the economy of the Gulf of Mexico will be living with the consequences of this for many years.

6pm CDT: Doug Suttles makes an appearance on CNN, and says that BP has restarted pumping mud into the well within the last hour, after earlier suspending pumping as reported by NYT and AP (see below). Based on Suttles comments it appears that pumping actually stopped for several hours earlier today as BP's engineers tried to judge what had happened.

Asked by CNN what had happened, Suttles said: "Too much of the mud is exiting the riser as opposed to going down the well bore." This could be fixed in several ways, including the infamous "junk shot", using a more viscous mud type, or finally restarting pumping at very high rates.

Shouldn't BP have given more information about the state of the pumping and the top kill, given the level of public interest? "I should apologise to folks that we haven't given more data on that, we've been so focussed on the operation," said Suttles. Once again, "We should know in the next 24 to 36 hours" if it's successful.

James Carville pops up on CNN to comment on Suttles' revelation about the stop-start pumping: "This is why no one believes BP any more."

6.55pm CDT: So, where are we now? It turns out that, rather than pumping mud into the well as part of its top kill procedure, that BP actually suspended pumping around midnight local time last night, because it needed more mud to be brought in. None of this was mentioned in the course of the day by BP, which merely repeated the 24-hour window line that it has maintained since the top kill operation started on Wednesday. Pumping has now resumed – although we only have BP's word for that.

The problem appears to be that the drilling mud was gushing from the the broken drill pipe. That doesn't mesh with BP's repeated statements during the day that everything was going according to plan. "The fact that we had a bunch of mud going up the riser isn't ideal but it's not necessarily indicative of a problem," said spokesman Tom Mueller told AP tonight.

BP only made these revelations after first the New York Times and the Associated Press reported that the top kill pumping had ceased. Now BP says it could be late tomorrow or the weekend before it knows if it has cut off the oil from the ruined well.

7.30pm CDT: The Washington Post has more details on BP's stop-start top kill process, and mentions that BP is considering a "junk shot" tonight:

Doug Suttles, BP's chief operating officer, said that on Wednesday the company had blasted high-pressure mud into the leaking well two times, trying to force the oil down in a procedure compared to using one firehose against another.

After doing it twice, Suttles said, the company stopped about midnight Wednesday, and spent Thursday assessing the plumes still shooting out of broken machinery. He said that company officials believed the two efforts had probably made some progress.

"I think some people believe it has. Some people believe it's less obvious it has," Suttles said. "What we do believe we've done is successfully pumped some mud, some of this drilling mud, into this wellbore."

But, Suttles said, oil was still coming out, despite these efforts: "What we do know is that we have not yet stopped the flow."

He said the company would try the procedure again Thursday evening and might add chunkier debris such as rubber balls to the mix in hopes of clogging the leaking pipe. That procedure is known as a "junk shot."

8pm CDT: This seems like a good place to wrap things up for the night. The latest word from BP is – guess what? – it will take another 24 to 48 hours before we know if top kill has been successful. But in the meantime, nothing has gone wrong, according to BP.

Since this is a hugely technical exercise, we turn to the experts, and few are more expert than Eric Smith of the Tulane Energy Institute, who says that BP's stop-start activities do not indicate the top kill had failed.

"The good news is that they pumped in up to 65 barrels a minute and the thing didn't blow apart," Smith told AP. "It's taken the most pressure it needs to see and it's held together."

The talking heads on cable teevee are demanding that a spill czar be appointed to take charge of things – someone like, here's a wild guess, Colin Powell.

Tomorrow Barack Obama visits Louisiana to see for himself.

... ...
www.guardian.co.uk Full Story]]>

• BP restarts top kill pumping after suspension
• Gulf of Mexico leak worse than Exxon Valdez spill
• Obama says: 'I take responsibility' for clean-up
• Head of the US minerals management service resigns

All Thursday's live updates as they happened

10.40am:

BP began pumping mud into the Macondo well at 7pm BST yesterday – a procedure (slightly) more technically known as 'top kill'.

This morning the oil company said things are going to plan with the latest attempt to stem the oil flow, or at least did not announce that anything is going wrong:

'Top kill' operations continued over the night and are ongoing. There are no significant events to report at this time. BP will provide updates on progress as appropriate.

In addition to watching the progress of the top kill, it will be interesting to see how the markets react to the announcement from the Obama administration that proposed exploratory drilling in the Arctic Ocean will be suspended until 2011 – potentially disrupting Shell Oil's plans to begin drilling five exploratory wells this summer.

Yesterday Barack Obama described the disaster as "heartbreaking" while BP chief executive Tony Hayward went for the phrase "absolutely gutted", in an apparent contest to see who was the most concerned as opinion polls suggest large parts of the US public are dissatisfied with both men.

Follow updates on the top kill, and get all your oil spill news here.

11.05am:

This interactive graphic by my colleague Paddy Allen show how the top kill should work.

BP's live feed of the oil leak doesn't appear to be working, but some other sites have video streams that I've had more luck with so far this morning.

The oil company does warn that the stream "may freeze or be unavailable from time to time", but other sites were running the footage not so long ago when BP was down – PBS news's footage was working well earlier, although it seems to have stalled now.

I'll keep looking for reliable streaming of the oil – BP said that throughout the top kill procedure "very significant changes in the appearance of the flows at the seabed may be expected", which could be exciting.

(Although it did add, disappointingly, that: "These will not provide a reliable indicator of the overall progress, or success or failure, of the top kill operation as a whole.")

11.30am:

The top kill has worked above ground but has never before been tried 5,000 feet beneath the sea. (Keen followers of the Gulf oil spill so far will recall that the same applies to every technique – and let's face it, there have been many – that BP has employed so far, as there have never been an oil leak this far beneath the surface before).

BP has rated the latest attempt's chance of success at 60 to 70 percent.

"The absence of any news is good news," said Coast Guard Admiral Thad Allen, who's overseeing the operation.

"It's a wait and see game here right now, so far nothing unfavorable."

Incidentally, the engineers working to stop the spill have come up with some ingenious names for their efforts so far. From introducing the word 'cofferdam' to a wider audience, to reinventing the top hat as a (failed) device to capture the oil, to the brilliantly named "junk shot", the terms for BP's attempts have never failed to capture the imagination.

Yesterday my colleague as conjuring up "a new TV series starring Jeremy Clarkson testing firearms", and 'top kill' is definitely my
favourite so far, although to me it sounds more like a Jean Claude Van Damme film.

.
.
What does the term mean to you? Comment below or email adam.gabbatt@guardian.co.uk if you're shy.

.

11.44am:

The second I start whinging in the comments section, the second the video starts streaming again – at least it is on PBS Newshour's web site.

12.21pm:

Hank Stuever, from the Washington Post, has been watching the live coverage of the oil spill too. He's not overly enamoured with it:

Spillcam combines the dread of horror films with the monotony of Andy Warhol's eight-hour silent movie of the Empire State Building. There is no sound and nothing happens, except the inexorable, unending flow. You watch a little, and then a little more, and then you can't stop watching as a steady plume of dark brown oil belches upward from the floodlit, rocky ocean floor.

12.35pm:

Paul Pemberton emails to recommend the 'Simultaneous Operations Overview - Subsea Operations' section of the BP web site, which is much more interesting than it sounds.

The site has lots of graphics showing the different types of equipment being used in both the top kill attempt and the wider clean up operation.

This image showing the vessels in action on the surface is a helpful source.

12.58pm:

The Los Angeles Times is reporting that President Obama will announce today he'll extend a moratorium on new deepwater drilling for six months in the wake of the Deepwater Horizon disaster.

This is more information coming out about the month long review the US interior ministry has just conducted into oil drilling. The Obama administration is also suspending proposed exploratory drilling in the Arctic Ocean following the report from interior secretary Ken Salazer.

Elsewhere Newsweek has an interesting article on which of the people most often quoted on the Gulf oil spill you can trust.

They've assessed the trustworthiness of interior secretary Ken Salazar, Louisiana governor Bobby Jindal and BP's Doug Suttles, among many others, with lots of links to examples of experts telling, or manipulating, the truth.

1.50pm:
This is Matthew Weaver taking over from Adam Gabbatt. BP's reputation is taking a massive kicking online. BP bashing on Twitter is being led by the spoof account @BPGlobalPR. It features links to T-shirts bearing a smudged-oil logo "BP cares". The same ironic term is also trending on the network at #BPcares.

Over on Facebook almost 150,000 users have expressed support for a group called BoycottBP.

2.22pm:
Top Kill has succeeded in blocking the leak, according to the LA Times citing a coast guard official Thad Allen.

The live feed still appears to show oil spewing from the sea bed, and the latest from BP is that there is nothing to report.

But the LA Times says:

The "top kill" effort, launched Wednesday afternoon by industry and government engineers, has pumped enough drilling fluid to block all oil and gas from the well, Allen said. The pressure from the well is very low, but persists, he said.

2.34pm:
BP's share price has increased by almost 6% on the news of Top Kill's apparent success, according to my colleagues on the business desk.

The US Geological Survey is due to hold a conference call with reporters at 3pm. Our US business correspondent Andrew Clark is due to take part.

The LA Times reporter, Jim Tankersley, who broke the story about about Top Kill succeeding, has back tracked slightly.

He tweeted: "To be clear: #topkill is not yet a success. Oil and gas flow have stopped. Small pressure persists. Cementing still to come. #oilspill."

2.43pm:
The New Orleans news site Nola.com is not getting quite as excited by Thad Allen comments, as the LA Times.

It reports:

An attempt to kill the runaway deepwater horizon well spilling oil into the Gulf of Mexico is going according to plan so far, leaving the coast guard admiral in charge of managing the spill "cautiously optimistic" but unwilling to say the well is capped.

2.55pm (8.55am CDT):
The LA Times has re written its Top Kill "success story" with the following clarification.

An earlier version of this story termed the effort "successful." Officials clarified that neither government nor BP officials had declared the effort a success yet. They caution that only after the cementing is complete and the well is sealed can the top kill be called successful.

3pm:

Here's a sumnmary of the main points so far:

• Reports say that the 'top kill' operation is going to plan and has stopped the flow of oil from the spill. Earlier reports that it had succeeded have not been confirmed by BP or government officials
• BP's share price has increased
• President Obama has extended a moratorium on new deepwater drilling for six months. The president is due to give a press briefing at the White House later.

3.20pm (9.20am CDT)
News is emerging on Twitter about what is being said at US Geological Survey (USGS) conference call.

Kate Sheppard, environmental reporter from Mother Jones, is providing a running commentary.

Flow rate call with USGS. Dr. Marcia McNutt, chair of flow rate technical group, talking to reporters.

McNutt says numbers didn't matter in response, which has "been based on a worst-case, catastrophic scenario."

Surface observations indicate 130k-270k barrels as of May 17, estimates that equal amount burned, dispersed, etc.

One of the teams evaluating flow says could be as high as 25,000 barrels, which would be 5x the previously accepted figures from NOAA/BP.

McNutt says that reasonable lower figure is 11,000 barrels per day, which is already more than twice as much as # given by NOAA, BP so far.

Team looking at satellite info estimates 12,000-19,000 per day flow from well. #BPspill 4 minutes ago via web

A Twitter stream from the Phoenix Sun also has a commentary on the call.

3.23pm (9.23am CDT):
Andrew Clark, who has also been listening to the USGS conference call, has this:

Marcia McNutt, director of US Geological Survey (and scientific adviser to interior sec Ken Salazar), has been giving figures suggesting flow of oil from the leak has been much higher than BP estimated.

According to three different scientific measurement methods, the leak has been flowing at minimum of 12,000 barrels per day, and it could be as much as 19,000 barrels. That's way above BP's estimate of 5,000 barrels.

As of May 17, a Nasa imaging plane found 130,000 to 270,000 barrels of oil on the surface of Gulf. Roughly the same volume again had already been burned, skimmed, dispersed or evaporated.

"This is obviously a very, very significant environmental disaster," McNutt said.

3.35pm (9.35am CDT):
Just to be clear: the USGS did not comment on the top kill operation, it was discussing the damage so far.

But Thad Allen, the US coast guard official, has been discussing top kill. He told the radio station NPR that it was too early to say whether it had succeeded:

"Over the course of the last 12 to 18 hours, they have been able to force mud down and not allow any hydrocarbons to come back up,"

"It's a matter of put some mud down, take some pressure readings, put some mud down, take more pressure readings. One thing they don't want to do is put so much mud down that there may be a structural problem for the well-bore casing and potentially rupture them, which would be something we wouldn't want to have happen."

3.43pm (9.43am CDT):
The head of the troubled US Minerals Management Service, Elizabeth Birnbaum, has been sacked.

The agency was heavily criticised over the leak. An official report found that it allowed staff at oil and gas firms to fill in inspection reports in pencil, with regulators later going over the answers in ink.

3.51pm (9.51am CDT):
The leak could have been five times worse than BP estimates, according to another disturbing update from the USGS. Andrew Clark writes:

To clarify further, the government had three measurement methods. All three agreed the spill has been at least 12,000 barrels per day. Two of them said an upper limit 19,000 per day. The third put the upper limit at 25,000 barrels per day, which would be five times what we were previously told both by the administration and by BP.

3.56pm (9.56am CDT):
Better news from Andrew Clark on top kill:

I've been talking to David Summers, a professor of mining engineering at Missouri University of Science and Technology, who has been following the operation closely.

He says that about seven hours after beginning the "top kill" attempt yesterday, BP was able to drop the pressure of mud being pumped into the well - which was a good sign.

"That means they had enough pressure to displace the oil from the well into the rock formation," says Summers, so the well now contains a column of BP's drilling mud instead of a spurt of oil.

However, the job isn't quite done yet: "They haven't been able to totally balance the pressure yet. The column of mud in there should be stable enough to stand there by itself. But they're still having to apply a little bit of pressure to keep the column stable. That means they may not have got the mud all the way down the well yet."

Still, Summers reckons it's going as well as can be expected and based on what he's seeing, he's optimistic: "The whole thing could be sealed and capped by this time tomorrow."

4.21pm (10.21am CDT):
This is Richard Adams in the Guardian's Washington office, taking over from Matt Weaver for the rest of the day.

10.38am CDT: It's a stinking hot day here in Washington, and the White House press corp is already assembled outside in the blazing sun waiting for President Obama's press conference to start at 12.45pm ET.

More bad news: the Deepwater Horizon spill is officially larger than the Exxon Valdez spill in Alaska back in 1989, making it now the worst oil spill in US history by some distance depending on which estimate you prefer.

Here's the AP description:

Even using the most conservative estimate, that means the leak has grown to nearly 19m gallons, surpassing the size of the 1989 Exxon Valdez disaster, which at about 11m gallons had been the nation's worst spill. Under the highest estimate, nearly 39m gallons may have spilled.

10.43am CDT: More on the Minerals Management Service director Elizabeth Birnbaum, who left her post today after scathing criticism of the agency for its lax work and overly-cozy relationships with the industry it was regulating. Birnbaum has only been in the job since July last year so it seems a little harsh. Ken Salazar, the interior secretary, said that Birnbaum resigned "on her own terms and of her own volition", rather than being sacked. But in such situations there's always a jumped/pushed element.

11.04am CDT: There's a fantastic on-the-ground report from Mac McClelland, a reporter for Mother Jones magazine, who details her run-ins with BP staff and local police in trying to report from the beaches of Louisiana, and what she found there:

The shoreline is packed with men in hats and gumboots and bright blue or white shirts. Nearly all are African-American, all hired from around New Orleans. They tell me they've been standing in these exact same spots for three days. It's breathtakingly hot. They rake the oil and sand into big piles; other workers collect the piles into big plastic bags, and still other workers take them to a plant where the sand is separated out and sent to a hazardous-waste dump and the oil goes on for processing. Then the tide comes in with more oil and everybody starts all over again. Ten dollars an hour. Twelve hours a day.

11.15am CDT: Not so long ago the Republican governor of Louisiana, Bobby Jindal, was telling anyone who would listen that the federal government was too big. For obvious reasons he now takes a rather different view, and will tell anyone who will listen that the federal government just isn't doing enough.

And because of the oil spill he doesn't have enough time to finish writing his biography:

A Jindal spokesman confirmed Tuesday that the governor's upcoming memoir, titled Real Hope, Real Change: New Conservative Solutions to Rescue America, won't be released in July as planned.

Those new conservative solutions to rescue America will just have to wait until the old federal government has rescued America from the oil spill.

11.30pm CDT: The cables are starting to count down the minutes until Obama's press conference in 15 minutes' time. "Arguably the most important if not the most important ever," says CNN's Wolf Blitzer, playing down the whole event.

CNN's John King wants to know why President Obama isn't showing more anger to the public, so maybe at this press conference the president will punch someone from BP to make that point. And why not? (Because violence is never the answer, kids.)

Wolf Blitzer says that he tweeted this morning that Obama was losing the crucial CNN guest commentator demographic, meaning James Carville, the Louisiana native who isn't happy. And if you've lost James Carville, you've lost middle America, right? Sorry, that was Walter Cronkite.

11.50am CDT: Obama's now talking in the East Room, starting with a quick update on the spill and the top kill operation.

"This procedure offers no guarantee of success," warns Obama. On BP, he says: "We will demand they pay every dime for the damage they have done.... Make no mistake, BP is operating at our direction."

"Those who think we were slow in our response or lacked urgency don't know the facts."

11.55pm CDT: Obama's now laying into the "scandalously close relationship between the oil industry and those who were regulating them", and how laws were "tailored by the industry to serve its needs and not the public's."

Obama made official the announcement of action against deep-sea drilling:

• suspend two permits to drill off the coast of Alaska
• cancel oil lease sales off the coast of the Gulf of Mexico and Virginia
• suspend new permits for deep water wells for a further six months
• suspend action of current wells being drilled in the Gulf of Mexico (that is, new wells being drilled, not wells in operation)

12.02pm CDT: CNN is tastefully carrying a small window with the "oil spill cam live" in the bottom righthand corner of the screen, showing oil (or mud, by now, we hope) gushing out while Obama is speaking.

12.07pm CDT: Asked about public concern at BP's continued involvement in the efforts to stop the spill, Obama responds: "This notion, that for the last three or four weeks somehow the federal government is sitting on the sidelines and we've just been letting BP make the decisions, is not true."

Obama says that one of his first questions, during a meeting in the situation room early on in the crisis, was whether the government had the technology to tackle to leak. He was told that it didn't, and that BP had did. "Should the federal government have this technology?" Obama said, and that will be one of the issues that the new panel being set up will consider.

"But for now, BP has the best technology, along with other companies, in capping the well down there."

12.18pm CDT: Chuck Todd of MSNBC asks Obama to address the Katrina comparisons, a very popular topic of conversation on the US right and left.

"I'll leave it to you guys to make these comparisons and make judgments. What I'm spending time thinking about is how we solve the problem," replies Obama, in a lofty tone. "I am confident people are going to look back and say this administration was on top of an unprecedented crisis."

Obama is very much on the defensive here and is lacking fluency in his answers. "I think there was a lack of anticipating what the worst case scenarios would be." No, really?

12.33pm CDT: Oh a question from Helen Thomas, about why America's military is still in Afghanistan. Because she has been in the White House press corp since the Chester Arthur administration, Obama politely responds.

Speaking of which, President Arthur would have done a great job at cleaning up this spill. He certainly cleaned up the US civil service.

Now the New York Times reporter is asking if Elizabeth Birnbaum was fired or sacked or what? "I only found about it this morning," says Obama, "I don't know the circumstances." Mmm.

12.40pm: "You never heard me say, 'drill, baby, drill'," says Obama.

On the live video feed from the well head, a robotic arm has appeared. Exciting? No, it appears to be part of the submarine.

Now there's a question about – really? – Arizona's immigration law and the decision to send 1,200 National Guard members to the border with Mexico. Obama is asked if he is favour of boycotting Arizona (because of its quasi-racist new law which requires the police to ask for immigration status of anyone they suspect of being an illegal immigrant).

"I'm president of the United States, I don't endorse boycotts or not endorse boycotts. That's something that the private citizens can make a decision about," says Obama, sensibly although perhaps a little too even-handedly.

12.47pm CDT: "And it's not just me, by the way. When I woke this morning and I'm shaving and Malia knocks on my bathroom door and she peeks in her head and she says, 'Did you plug the hole yet, Daddy?' Because I think everybody understands that when we are fouling the Earth like this, it has concrete implications not just for this generation, but for future generations," says Obama, now making the case that he is fully engaged on fixing the spill disaster, and so it seems is the rest of his family.

This is from the last question of the press conference, from Major Garrett of Fox News, who asked: "Is your boot on the neck of BP?", employing the metaphor used by interior secretary Ken Salazar.

"I would say we don't need to use language like that, what we need is action to make sure BP is made accountable," replies Obama. "The Gulf is going to be affected in a bad way. So my job right now is to make sure everyone in the Gulf understands, this is what I think about when I wake about in the morning and the last thing at night.

And Obama finishes by saying that he is responsible: "In case you're wondering who's responsible, I take responsibility. It is my job to make sure this thing is shut down."

12.56pm CDT: So the press conference is over, but this wasn't Obama's best effort. "People want a more visceral president," opines John King, a journalist who works for CNN.

Everyone on CNN agrees that because Obama has been in office now for a year and a half (actually, 16 months, but hey) everything is now his fault. Which seems more than fair. By now he should have got around to reading all the drilling licenses and environmental exemptions.

1.09pm CDT: Now the robotic arm appears to be using a spanner on the live video feed from the ROV. It's very cool, although to be honest it's doing a rubbish job.

TV expert thinks that it might be something to do with adding a sensor to measure the temperature. Apparently this is all good news.

(The spanner – or wrench, if you are American – is now just sitting on top of the leak.)

1.15pm CDT: Has the tide turned? It's now 24 hours since the top kill operation began – the initial period that would dictate the success or failure, according to BP – and all the news so far is that it appears to be working.

The colour of the fluid, as seen on the live feed, has certainly lightened since yesterday, and the experts are hailing this as an excellent sign of progress. "The fluid you see right now is almost 100% the fluid that's being pumped down from the surface to create the seal," says Professor Don van Nieuwenhuise from the University of Houston's geo-science programme, on CNN. "From what I can see it's going very well." Van Nieuwenhuise is a veteran of several top kill operations.

When can the cement go in and seal it up? That's the tricky part, the professor says, since it can lead to another rupture.

The New York Times is also cautiously reporting on the success of top kill:

The latest effort to plug a gushing underwater oil well in the Gulf of Mexico appeared to be working, officials and engineers said on Thursday morning, though definitive word on its success was still hours away.
....
But there were indications that the heavy fluid, called mud, was slowly building up within the well bore as it was being pumped from surface ships through pipes on the seafloor. At first, most of the mud was carried away by the oil and gas streaming up through the well at high pressure, but with enough mud being pumped in at a fast enough rate, it started accumulating inside the well as intended. Unless something goes wrong, at some point, enough mud — and thus enough weight — would accumulate to overcome the upward pressure of the escaping oil and gas, and seal the well.

A senior technician working on the measure said on Thursday that the vast amount of data collected so far was positive, and that there was general optimism that it was succeeding. Planning has begun for cementing the well, the next step in sealing it after the flow of oil and gas is stopped by the drilling mud, but that stage would not be undertaken for at least several hours.

Yesterday: The flow on Wednesday afternoon.

Notice how the flow was longer and straighter in the [bottom] image, indicating that it was at higher pressure (velocity) and that now it blows out at much closer distance, meaning it doesn't have the same pressure (velocity).

Today: the flow as seen this morning.

1.45pm CDT: To gauge how the fluid from the leak has changed, here are two screen grabs from today and yesterday, from the excellent site The Oil Drum, which is providing some valuable expert commentary:

Below ... are two pictures to show why I believe that the injection pressure of mud into the well has dropped, indicating that BP have filled the well, and are now holding pressure to see if there are any problems. I would assume, if none develop, that they will inject cement to seal the top of the well, sometime today.

2.35pm CDT: The AP are reporting that seven workers helping to clean up the Gulf oil spill are still in hospital after they reported dizziness, headaches and nausea while working on boats off the Louisiana coast:

West Jefferson Medical Center spokeswoman Taslin Alfonzo said Thursday that doctors believe the likely cause is chemical irritation and dehydration from long hours working in the heat. Alfonzo said the workers told doctors they believe chemicals used to break up the oil made them sick.

Authorities say the workers became ill Wednesday while cleaning up oil in Breton Sound, southeast of New Orleans. Officials ordered all 125 commercial boats working the cleanup there to leave the area.

3.15pm CDT: Oh dear. It appears that some evil hackers managed to briefly hijack the @BP_America official Twitter account.

According to Fox News, at least one rogue tweet was up on the official BP feed for only a brief time before it was caught by an eagle-eyed BP employee (at least they're good at something). The offending tweet read: "Terry is now in charge of operation Top Kill, work will recommence after we find a XXL wetsuit. #bpcares #oilspill".

3.30pm CDT: The Coast Guard is holding a press conference in Venice, Louisiana, saying that mud is still being pumped into the well and "wait and see" is still the order of the day. Admiral Thad Allen says mud is still coming out of the leak, which suggests the pressure still hasn't been contained. "They said this could take 24 to 36 hours, and they are in the process of monitoring it," said Allen, who was more downbeat than his previous appearance this morning.

3.54pm CDT: Vermont's independent Senator Bernie Sanders has a piece on the Gulf oil spill over at Comment Is Free America:

Offshore drilling simply does not achieve the goals that its advocates claim, and it is not worth the risk. If we are serious about wanting to break our dependence on foreign oil and move to energy independence; if we want to lower the cost of energy; if we want to combat climate change and cut greenhouse gas emissions; if we want to create millions of new jobs – then more offshore drilling is not the way to go.

4.02pm CDT: Admiral Thad Allen pops up on MSNBC to be interviewed/shouted at by Chris Matthews. Matthews barks at the admiral to ask if top kill is working. Allen won't be drawn, but does say: "They've successfully done something at 5,000 feet that's never been done before."

On the idea of getting a fleet of supertankers to cruise around sucking up oil from the water's surface, as was done off Saudi Arabia in the 1990s, Adm Allen says there are various problems, such as not having enough room around the Deepwater rig site, but that it's being considered.

4.30pm CDT: Bad news: the New York Times is reporting that the top kill effort has been suspended by BP because too much fluid is still escaping from the leak.

BP had to halt its ambitious effort to plug its stricken oil well in the Gulf of Mexico on Thursday afternoon when engineers saw that too much of the drilling fluid they were injecting into the well was escaping along with the leaking crude oil.

A technician at the BP command center said that pumping of the fluid had to be stopped temporarily while engineers were revising their plans, and that the company hoped to resume pumping by midnight, if federal officials approved.

The technician, who spoke on condition of anonymity because he was not authorized to brief reporters, said the problem was not seen as serious. "We're still quite optimistic," he said, but cautioned: "It is not assured and its not a done deal yet. All of this will require some time."

The NYT is doing some top reporting work on top kill.

5.15pm CDT: The Associated Press is confirming the New York Times story, mentioned below, that BP has suspended top kill operations for the time being:

BP is pausing its unprecedented attempt to plug the Gulf of Mexico oil leak, saying it wants to monitor the effects of the top kill attempt.

BP said Thursday that nothing was going wrong with the procedure that involves force-feeding mud into the blown-out well in an attempt to overcome the oil flowing upward.

BP says it hopes to resume shooting mud into the well Thursday night. Chief Operating Officer Doug Suttles says he is not surprised that it is taking longer than expected.

5.45pm CDT: My excellent colleagues Andrew Clark and Suzanne Goldenberg round up the latest Gulf oil spill news, including this dire warning:

Scientists warned there was potential for even greater damage with a forecast of an unusually hazardous hurricane season. The national weather service in its yearly forecast for the hurricane season starting 1 June predicted between eight to 14 hurricanes across the Atlantic. Of those, three to seven could be major hurricanes, category three storms or higher. Hurricane Katrina was a category three.

Amid all the talk of technology and top kills, it's easy to overlook the risks that remain, and how the people and the economy of the Gulf of Mexico will be living with the consequences of this for many years.

6pm CDT: Doug Suttles makes an appearance on CNN, and says that BP has restarted pumping mud into the well within the last hour, after earlier suspending pumping as reported by NYT and AP (see below). Based on Suttles comments it appears that pumping actually stopped for several hours earlier today as BP's engineers tried to judge what had happened.

Asked by CNN what had happened, Suttles said: "Too much of the mud is exiting the riser as opposed to going down the well bore." This could be fixed in several ways, including the infamous "junk shot", using a more viscous mud type, or finally restarting pumping at very high rates.

Shouldn't BP have given more information about the state of the pumping and the top kill, given the level of public interest? "I should apologise to folks that we haven't given more data on that, we've been so focussed on the operation," said Suttles. Once again, "We should know in the next 24 to 36 hours" if it's successful.

James Carville pops up on CNN to comment on Suttles' revelation about the stop-start pumping: "This is why no one believes BP any more."

6.55pm CDT: So, where are we now? It turns out that, rather than pumping mud into the well as part of its top kill procedure, that BP actually suspended pumping around midnight local time last night, because it needed more mud to be brought in. None of this was mentioned in the course of the day by BP, which merely repeated the 24-hour window line that it has maintained since the top kill operation started on Wednesday. Pumping has now resumed – although we only have BP's word for that.

The problem appears to be that the drilling mud was gushing from the the broken drill pipe. That doesn't mesh with BP's repeated statements during the day that everything was going according to plan. "The fact that we had a bunch of mud going up the riser isn't ideal but it's not necessarily indicative of a problem," said spokesman Tom Mueller told AP tonight.

BP only made these revelations after first the New York Times and the Associated Press reported that the top kill pumping had ceased. Now BP says it could be late tomorrow or the weekend before it knows if it has cut off the oil from the ruined well.

7.30pm CDT: The Washington Post has more details on BP's stop-start top kill process, and mentions that BP is considering a "junk shot" tonight:

Doug Suttles, BP's chief operating officer, said that on Wednesday the company had blasted high-pressure mud into the leaking well two times, trying to force the oil down in a procedure compared to using one firehose against another.

After doing it twice, Suttles said, the company stopped about midnight Wednesday, and spent Thursday assessing the plumes still shooting out of broken machinery. He said that company officials believed the two efforts had probably made some progress.

"I think some people believe it has. Some people believe it's less obvious it has," Suttles said. "What we do believe we've done is successfully pumped some mud, some of this drilling mud, into this wellbore."

But, Suttles said, oil was still coming out, despite these efforts: "What we do know is that we have not yet stopped the flow."

He said the company would try the procedure again Thursday evening and might add chunkier debris such as rubber balls to the mix in hopes of clogging the leaking pipe. That procedure is known as a "junk shot."

8pm CDT: This seems like a good place to wrap things up for the night. The latest word from BP is – guess what? – it will take another 24 to 48 hours before we know if top kill has been successful. But in the meantime, nothing has gone wrong, according to BP.

Since this is a hugely technical exercise, we turn to the experts, and few are more expert than Eric Smith of the Tulane Energy Institute, who says that BP's stop-start activities do not indicate the top kill had failed.

"The good news is that they pumped in up to 65 barrels a minute and the thing didn't blow apart," Smith told AP. "It's taken the most pressure it needs to see and it's held together."

The talking heads on cable teevee are demanding that a spill czar be appointed to take charge of things – someone like, here's a wild guess, Colin Powell.

Tomorrow Barack Obama visits Louisiana to see for himself.

... ...
www.guardian.co.uk Full Story]]> http://about-marine-biology.com/marine-biology-1/bp-oil-spill-top-kill-live-coverage/feed/ 0 http://about-marine-biology.com/marine-biology-1/what-are-the-top-schools-in-the-nation-for-marine-biology-and-for-zoology/ http://about-marine-biology.com/marine-biology-1/what-are-the-top-schools-in-the-nation-for-marine-biology-and-for-zoology/#comments Sat, 29 May 2010 05:15:36 +0000 T11 http://704bae253830f58591b53dc53f91afc9_67179b0dfb56b0c4437e02a633f7c848 Full Story

]]> Full Story

]]> http://about-marine-biology.com/marine-biology-1/what-are-the-top-schools-in-the-nation-for-marine-biology-and-for-zoology/feed/ 0