NEW ORLEANS, Louisiana (CNN) -- Tropical Depression 3 formed near the Bahamas Thursday morning, the National Hurricane Center said, carrying sustained winds of 35 mph and possibly threatening operations to clean up the BP oil spill in the Gulf of Mexico.
The system showed significant signs of intensification during the overnight hours with thunderstorm activity increasing, CNN meteorologist Sean Morris said. Several forecast models show the system could move into the Gulf.
The National Hurricane Center issued tropical storm warnings and watches for portions of the Bahamas and Florida. If the system is powerful enough to become a tropical storm, with sustained winds of at least 39 mph, it would be named Bonnie.
Retired Coast Guard Adm. Thad Allen, who's leading the federal response to the spill, said Wednesday a tropical storm making a direct impact on the area could disrupt operations for 10 to 14 days.
BP has been working on a relief well that it has said will be the permanent fix to shut down the well. But because of the threat of inclement weather, BP has put the "casing" process of the relief well on hold, a BP spokesman told CNN Thursday morning.
Allen said a plug has been placed in the area of the well where the casing is located.
"We haven't completely stopped operations on the relief well, but we've put this -- basically this plugging device -- in to hold what we've got right now -- pending the decision on whether or not we can remain on scene," Allen said. "If we remain on scene, we'll remove that device and go on and proceed to lay the casing."
BP is also weighing a tactic called "static kill" that could help seal the broken well. The process involves pumping mud into the well to force oil back into the reservoir below. BP could begin a "static kill" as early as the weekend, weather permitting. The operation would also depend on governmental approval and the casing being installed, Allen said Wednesday.
BP said Thursday it was continuing well integrity testing, as the new cap that was placed on the sunken well July 12 was still keeping the oil inside and pressure was rising slowly. Though the new cap has stopped the flow of oil into the Gulf, government officials and BP have said that the cap is only a temporary fix for the oil disaster, which started when the Deepwater Horizon rig exploded and sank April 20.
The relief well is scheduled to be in place by the end of July if the approaching bad weather does not change that.
Severe weather could also cause an environmental setback. If the tropical weather system makes its way to the Gulf coast marshlands, it could diminish or erase encouraging signs of recovery from the BP oil spill, according to a scientist who spearheaded the first major examination of the Louisiana coast wetlands.
"Early marsh regrowth could easily be taken away with high winds and waves," said Tom Bianchi, a Texas A&M oceanography professor, who has spent his career researching marshes.
Bianchi, who used to live in New Orleans and lost his old home to Hurricane Katrina, said he felt an obligation to find out the status of the coastal wetlands in his former home state.
"I had to return. I had to hope and I was, honestly, shocked that we saw signs of new life," he said. "The marshes are badly, badly damaged, but we found some regeneration."
Bianchi and researchers from several other universities studied the wetlands off Grand Isle, Louisiana, by boat over the past week, funded by a $114,000 emergency grant from the National Science Foundation. Several days of inspecting the swampy home of mussels, crabs, sea grass and microbial creatures yielded good news for a precious part of the region's food chain, Bianchi said.
Vice President Joe Biden is returning to the Gulf region on Thursday for the first time since June 29. He is scheduled to visit Theodore, Alabama, to review efforts to combat the oil disaster in the coastal town and talk to residents, the White House said.
The government has been holding hearings on Capitol Hill to determine how better industry regulation can prevent future oil spills. Interior Secretary Ken Salazar and newly appointed Bureau of Ocean Energy Management Director Michael Bromwich appeared Thursday before the House Oversight and Government Reform Committee. They were expected to discuss "how exactly they plan to implement the reorganization and increase oversight and accountability" at the agency, according to committee chairman Rep. Edolphus Towns, D-New York.
In Towns' opening remarks, he made clear that though his hearing would focus on the government's role in the disaster, ultimately BP is at fault.
"While the Interior Department is responsible for regulating the oil industry and they have been taking a lot of heat for that, it does not change the fact that BP was responsible for the safety of its oil well and BP was responsible in terms of responding to the oil spill," Towns said. "And it is BP that is ultimately responsible for the entire cleanup and the costs, as well as the job losses and lost income resulting from the spill."
BP said Wednesday that it has incurred $4 billion in costs related to the spill, including 75,433 claim payments totaling $226 million.
Committee member Rep. Darrell Issa, R-California, said there's plenty of blame to go around.
"There were two weak links that led to this disaster: British Petroleum acting irresponsibly, failing to maintain safety standards well-established in the industry; failing to maintain their own safety standards; and being in too big a hurry to cut corners, cut costs, ultimately leading to the loss of life and the loss of billions of dollars to the American people around the Gulf and beyond," Issa said. "But there was another weak link-- a well-noted weak link, one that this committee has been pursuing change for almost six years now from: Minerals Management Service, an organization that has checks and balances that mean nothing."
Salazar responded that on his watch, the Interior Department has been working on reforming the former Minerals Management Service, now known as the Bureau of Ocean Energy Management, Regulation, and Enforcement.
"People have been fired. People have been sent over for criminal prosecution. People have been suspended and we've done everything that we can to clean house from an ethics point of view," the interior secretary said.
-- CNN.Com's Ashley Fantz contributed to this report
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