On "AC360°," survivors of the BP oil rig explosion talk to Anderson Cooper about their 11 "fallen brothers." Watch "AC360°" live from the Gulf at 10 p.m. ET Thursday.
(CNN) -- Scientists now estimate the leaking BP oil well in the Gulf of Mexico was releasing 20,000 to 40,000 barrels -- or 840,000 to 1.7 million gallons -- per day through last week, the head of the U.S. Geological Survey said Thursday.
The scientists' previous estimate was 12,000 to 19,000 barrels per day.
The new estimate is of the well's flow rate prior to BP's cutting of the damaged riser pipe extending from the well's blowout preventer last week, U.S. Geological Survey Director Marcia McNutt said. After BP cut the riser on June 3, it placed a containment cap over the preventer's lower marine riser package to capture some of the leaking oil.
Scientists estimate that the spill's flow rate increased by 4 to 5 percent after the well's riser pipe was cut last week in order to place the cap atop the well.
BP says that with the cap, it is capturing about 16,000 barrels daily and funneling it to a ship on the surface. Before that, BP was capturing some oil through a siphon inserted into the well riser.
The latest figure was calculated in part by using high-definition video of the spill that BP released this week after demands from members of Congress.
Scientists from the Geological Survey, the Department of Energy and the National Oceanic and Atmospheric Administration and experts from universities and other research institutions worked on the latest estimates, McNutt said. The information is expected to help guide efforts to stop the spill and deal with its impact on coastal areas, fish and wildlife.
In a statement Thursday, BP said the company "fully supported this effort, providing the scientific team with data, including a considerable amount of high-resolution video."
Still, Rep. Edward Markey, D-Massachusetts, said there will be an opportunity in a few weeks for the scientists to get a better estimate of the size of the flow. The group has told BP that they could get a more accurate estimate if they can send down equipment to measure the flow as the company attempts to swap out the containment cap on the well.
BP has yet to agree to the request, Markey noted in a letter to the company Thursday. "There are concerns that, without the best information on the size and force of this gusher, that the effectiveness of the new containment cap and relief wells could be compromised," the letter says.
On Monday, BP announced that the new cap would fit better and serve as a better long-term containment option "to provide the greatest flexibility for operations during a hurricane and [it] is expected to be implemented in early July."
BP confirmed receiving Markey's letter. "We plan to respond in due course," BP said.
The new flow estimate came on a day when U.S. Coast Guard Adm. Thad Allen sent a letter to BP Board Chairman Carl-Henric Svanberg asking that he "and any appropriate officials from BP," meet June 16 with senior administration officials, including President Obama.
A senior administration official told CNN the meeting would take place at the White House.
Also Thursday, a federal official testified that the oil disaster is one in a long list of failures indicating that the oil and gas industry has failed to learn key safety lessons.
"The oil and gas industry must learn from its mistakes," testified Jordan Barab, deputy assistant secretary of labor for occupational safety and health, on Thursday.
Barab told the Senate Subcommittee on Employment and Workplace Safety that investigators are finding a lack of compliance during inspections of refineries.
"Time and again, our inspectors are finding the same violations in multiple refineries," he said.
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Incidents involving close calls, serious injuries and fatalities "are clear indication that essential safety lessons are not being learned," he said.
Subcommittee Chairwoman Patty Murray, D-Washington, cited a litany of incidents: Eleven workers died on the Deepwater Horizon rig in an April 20 blast that led to the current oil-well gusher in the Gulf; 15 workers died and more than 170 were injured in the BP Texas City refinery disaster in 2005; seven workers died in the Tesoro refinery fire in Anacortes, Washington, in April.
BP's response was not immediately available; the company didn't attend the hearing, an absence that infuriated Murray.
"Honestly, I find it very outrageous that even after an accident that killed 11 workers, BP is not putting a high enough priority on worker safety to send a representative to a hearing specifically focused on protecting workers in their industry," she said.
Sen. Johnny Isakson of Georgia, the ranking Republican on the subcommittee, said he supports offshore drilling but said that doesn't mean working Americans should tolerate "less than the maximum amount of security."
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The Deepwater Horizon catastrophe, experts said Thursday, highlights flaws in the drilling industry's main defense against oil and gas explosions: the blowout preventer, which is supposed to shut down an oil and gas well if something goes wrong.
Oil companies have treated such devices as virtually fail-safe. "They're certainly not fail-safe, because they didn't close this well," said petroleum engineering professor Paul Bommer of the University of Texas at Austin.
From 2000 to 2009, 72 spills dumped 18,000 barrels of oil into U.S. federal waters, versus 15 spills that put 2,000 barrels into the water during the prior decade, according to the Minerals Management Service of the Interior Department, which regulates energy exploration.
Avoiding such spills depends upon the reliability of the blowout preventer, which is essentially a faucet on top of the oil well that is intended to keep oil and gas from gushing to the surface. Rig workers use the preventer to keep a well under control, especially when oil and gas surge or "kick up" from a well.
When its valves don't do the job, the blowout preventer is intended to choke off the drilling pipe, like squeezing a straw while drinking.
And, if that fails to work, a blowout preventer has another line of defense: huge shear rams like giant scissors that are supposed to be able to cut and seal the drilling pipe.
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But, a mile underwater, where the pressure is intense, drill pipes need to be thick, especially the joints between them. And those joints are hard to cut.
"There are some parts of the pipe that the shears were never meant to cut," said Ford Brett, an expert in petroleum project management who is advising the Interior Department's oil drilling safety review.
"The blowout preventers had a probability of failing to crush that pipe that approaches 50 percent," said professor Robert Bea of the University of California at Berkeley, who is familiar with the study. "It would be like getting on an airplane having a 50 percent chance of making it to your destination."
Failures of basic communication sparked the ire of Sen. Bill Nelson, D-Florida, who blasted federal officials Thursday for not alerting local authorities that oil from the Gulf disaster had entered Florida waters.
"The Coast Guard is doing a great job, but they are stretched to the limit," Nelson said during a Senate hearing on the spill. "We are livid that the command and control is not there. ... Communication is not coming to the state and local government."
Billy Nungesser, president of Louisiana's Plaquemines Parish, told a Senate subcommittee that he didn't know where to direct his anger.
"I still don't know who's in charge," he said. "Is it BP? Is it the Coast Guard? ... I have spent more time fighting the officials of BP and the Coast Guard than fighting the oil." What is needed, he said, is someone "with the guts and the will to make decisions."
Responsibility is a key question for families of the 11 oil rig workers who were killed and the 15 others who were injured in the April 20 explosion of the Deepwater Horizon.
Victims and their families are suing BP and Transocean, the Swiss-based company that owns the drilling rig.
But getting a settlement from Transocean, the world's largest offshore drilling company, could be difficult.
The company has invoked a 19th-century American law to limit its liability to $26.76 million, a fraction of what the plaintiffs are likely to seek.
"It may work," said Martin Davies, professor of law and director of Tulane University's Maritime Law Center. "They've got a chance."
President Obama said Thursday that he had a "frank conversation" with congressional leaders about the fact that current federal laws are not adequate to deal with the disaster.
The White House and Congress agree on the need to update the laws in order to ensure that residents in the Gulf "are all made whole" and the government is in a "much better position" to respond to future environmental crises, he said.
BP has pledged to speed its payments to businesses that have suffered losses in the disaster, an Obama administration official said Thursday.