(CNN) -- The massive spill that has pumped oil into the Gulf of Mexico for nearly a month has laid bare the need for regulations covering the industry to be tightened, Interior Secretary Ken Salazar said Tuesday.
"Do the laws need to be changed?" he asked the Senate Committee on Energy and Natural Resources in one of his two Senate committee appearances of the day. "The answer is yes."
But Salazar expressed optimism that the spill may soon be stanched. Scientists and representatives of the oil giant BP, which is responsible for cleaning up the spill, have concluded that the best line of attack would be to carry out a "dynamic kill of the well," Salazar told the Senate Committee on Environment and Public Works.
Under the procedure, mud is inserted into the well, he said, referring to the drill bit lubricant that prevents oil or water from spurting through the drill hole.
"Hopefully, those efforts will contain the oil," he said about this weekend's planned intervention. "They'll stop the flow of oil and then move forward to what will be the ultimate demise of this well."
But any long-term solution will be achieved only by construction of relief wells, which are not expected to be completed before August, he said. Two of the wells are being drilled "just in case something goes wrong with the first one," he said.
BP was leasing the Deepwater Horizon from its owner, Transocean, on April 20, when an explosion on the drilling platform killed 11 people, sank the oil rig and triggered the mile-deep oil gusher that has defied efforts to stem it.
BP said Tuesday that the amount of oil flowing from the ruptured pipe into a collection tube has doubled to 2,000 barrels (84,000 gallons) a day.
But Salazar called the insertion tube and last week's failed attempt to cap the pipe by covering it with a dome "simply Band-Aids that will contain some of the oil, but probably will not contain all of the oil. In fact, it won't contain all of the oil."
Even determining what percentage of the spill that increased collection might represent was not clear, since reliable figures do not exist.
Officials were scrutinizing video of the discharge pipe in an attempt to figure out the rate at which oil was gushing into the gulf, Coast Guard Commandant Adm. Thad Allen told the Senate Committee on Commerce, Science and Transportation.
"We're trying to establish what is exactly flowing out of the riser pipe right now and trying to get an estimate of the overall amount of oil that has been released," he said.
Allen, who has been fighting spills for 30 years, is slated to retire from the Coast Guard on July 1. He called the gulf gusher "more complicated than any spill I've been been involved with."
In all, he said, about 20,000 people are employed in the gulf fighting the spill's spread.
But the federal government's effort is hindered by its failure to update its maps, the administrator of the National Oceanic and Atmospheric Administration told the same committee.
Many of the nation's environmental sensitivity index maps, which summarize what coastal resources are at risk if an oil spill occurs nearby, are outdated, said Jane Lubchenco.
"Twenty-one of 50 atlases are more than 10 years old," said Lubchenco. "Many of them do not reflect current information."
It would take $11 million to update those maps that are more than a decade old, but NOAA has not had the resources, she said. "The current request in our president's budget includes updating only one of those," she added.
"We have to attend to that," responded committee chairman Sen. Jay Rockefeller, D-West Virginia.
Asked if the reported existence of deep-sea plumes of oil some 10 miles long and three miles wide has been confirmed, Lubchenco said that researchers aboard the research vessel Pelican have "identified an anomaly that is subsurface that may be oil, but that has not yet been confirmed."
Lubchenco said the plume covered "a relatively large area," but she did not know its dimensions.
Analysis of samples should be complete within a week, she said. "What the instruments are showing is a very fine mist of something," she said. "It is not a glob, it is not big balls, it is not big drops. It's a fine mist."
If the oil reaches Florida's keys, it would be "significantly weathered, degraded and diluted," she said. "It's not as if there's going to be a massive amount of fresh oil washing up."
Asked about the potential impact of the oil on hurricane season, which begins June 1, Lubchenco said that too was uncertain. "The oil may actually prevent some evaporation and therefore diminish the power of a hurricane," she said. "It is unlikely it would be affecting its track. On the other hand, it would sort of depend on where the oil is and where the hurricane is."
She added, "The bottom line is we don't really know."
The scope of the disaster continued to spread as federal authorities closed more waters to fishing in the Gulf of Mexico, where commercial fishing is a $2.4 billion industry.
NOAA has suspended fishing in 19 percent of the Gulf over which the federal government has jurisdiction, Lubchenco said. That's up from 10 percent that NOAA had ordered closed to fishing Monday.
The expansion means 45,728 square miles are now closed to fishing.
To ensure that seafood harvested from the gulf is safe, NOAA is working with the Food and Drug Administration to "realign its assets to implement a broad-scale seafood sampling plan," Lubchenco said.
Several restaurants and seafood wholesalers in Louisiana and Florida filed a class-action lawsuit in federal court Tuesday against BP over the spill, according to a statement issued by a spokeswoman for the New Orleans, Louisiana, law firm representing them.
The businesses are covered by the Oil Pollution Act, said the firm, which is asking the court to clear the way for appropriate claims.
"As a result of the spill," attorney Stephen Herman said in a statement, "my clients will have a difficult time obtaining fresh, local seafood. They'll have to pay higher prices for the seafood, and they run the risk of losing customers as a result of higher prices and limited availability."
After a helicopter tour of the region, Louisiana Gov. Bobby Jindal noted Tuesday that the oil from a gusher 50 miles off the coast of Mississippi was reaching his state's shores.
"We saw some heavy oil come into the wetlands, come into the marshlands," he said. "You can see this is heavier oil, this is not just sheen."
Lawmakers focused their investigative powers on the spill Tuesday. In response to a request from Sen. Bill Nelson, D-Florida, and Sen. Barbara Boxer, D-California, BP began releasing videos of the spill showing it spurting out in powerful blasts.
The House Natural Resources Committee said that, beginning May 26, it will hold a seven-part hearing to investigate the incident and "examine the future of America's offshore oil and gas policy."
BP is responsible for stopping the gusher and paying for the cleanup. Homeland Security Secretary Janet Napolitano said the company has paid more than $9.6 million without denying a claim.
Asked whether he supports a bill to raise the liability limits from $75 million to $10 billion, BP Chairman Lamar McKay said, "Well, I haven't looked at the specific legislation. What we have been very clear about is the $75 million, we're going to exceed that, that's irrelevant, and we've said that it's just irrelevant in this case."
President Barack Obama said Tuesday he was disappointed that an effort to ensure oil companies pay fully for any disasters they cause had stalled in the Senate on a partisan basis.
"This maneuver threatens to leave taxpayers, rather than the oil companies, on the hook for future disasters like the BP oil spill," he said in a statement. "I urge the Senate Republicans to stop playing special interest politics and join in a bipartisan effort to protect taxpayers and demand accountability from the oil companies."
Obama has decided to establish a presidential commission to investigate the disaster, an administration official said. The panel will explore "a range of issues," including federal oversight of offshore oil drilling, safety aboard rigs and environmental protection, said the official, who spoke on condition of anonymity ahead of an official announcement.
And a top official of the Interior Department agency that oversees offshore drilling is retiring a month earlier than planned. Chris Oynes had told his bosses after the Deepwater Horizon explosion that he would retire at the end of June, but announced Monday that he would step down at the end of May instead, an administration official said.
Oynes has been associate director of the Minerals Management Service's Offshore Minerals Management Program since 2007. Critics have accused the service of being too cozy with the industries it regulates. A 2008 report from the Interior Department's inspector general found that employees received improper gifts from energy industry representatives and engaged in illegal drug use and inappropriate sexual relations with them.
Speaking before the Senate Committee on Energy and Natural Resources, Salazar outlined steps he has taken to overhaul the Minerals Management Service, which has been criticized for having a cozy relationship with the oil and gas companies it's tasked with overseeing.
Salazar said his department has worked aggressively to contain the spill and to limit its economic and environmental damage. "We will get to the bottom of this disaster and will hold those responsible accountable," he said.
He sought to assure lawmakers that he will crack down on drilling practices in the Gulf of Mexico, the source of about a third of U.S. oil production.
Salazar said Tuesday that those involved have been terminated and prosecuted, and other personnel actions had been taken.
"The employees at MMS, some 1,700 of them, most of them are good public servants," he said. "There are some bad apples at MMS, and we have taken care of them, and to the extent that MMS employees were involved in any kind of negligence here or any kind of failure they will also be held accountable."