With a thick shot of cement plugging the last worrisome part of BP's troubled well, government officials were one final pressure test away from declaring the source of America's worst offshore oil spill dead as early as Sunday.
If successful, the so-called "bottom kill" will close a chapter on a disaster story that began with a deadly explosion in the Gulf of Mexico and quickly became a central crisis for the Obama White House, a confirmation of the oil industry's inability to handle a major spill, and a reminder of the often risky and dangerous work required to feed the nation's fossil-fuel addiction.
Despite the known tally of the tragedy — the 11 men killed in the April 20 rig blowout, the lost season for the tourism and seafood industries, the thousands of dead creatures — a full accounting remains studded with unknowns, largely because it will take years to understand the disaster's effects on the environment.
"This spill began with a bang, ends with a whimper, and leaves a number of issues still screaming for attention," Rep. Edward J. Markey (D-Mass.), chairman of the House Select Committee on Energy Independence and Global Warming, said in a statement Saturday.
Much of the oil now floats beneath the ocean's surface. But with the public focused on the nation's economic malaise — and Washington lawmakers locked in partisan stasis —it remains to be seen whether this outsized environmental disaster will bring about major changes in the oil industry, energy policy, public opinion and politics.
"Moderate to heavy oil impacts" continue to hit roughly 109 miles of coastline, much of it in Louisiana, according to the federal government. But elsewhere in the gulf states, there are signs of a return to normal: Ribbons of surface oil have largely vanished, sunbathers are back on Florida beaches, seafood delicacies appear on New Orleans menus, and more fishing grounds open daily.
Yet unanswered questions stain the future: What will new federal regulations on the oil industry look like? Will they strangle jobs? Will tourists return? Will Americans again feel secure eating gulf seafood? Will BP really make good on its promise to pay for billions in potential damages?
"It's very confusing and dismal down here right now," said lifelong oysterman Dave Cvitanovich, who, like many Louisiana watermen, was drafted into BP's ad hoc cleanup industry that included flotillas of locals. "A hurricane comes and goes, and a week later you're back on your feet. But who knows whether this problem will still be around three months or a year from now?"
Of the estimated 4.9 million barrels of oil that gushed from the well, 25% was burned, skimmed or piped to tanker ships. A second 25% has evaporated or dissolved, according to government estimates.
Another 25%, classified by the government as "residual oil," consisted of light sheens on the water, thick goo on the shore and tar balls. The tar balls, though not harmful to humans, are likely to wash up on shore for some time.
"There's going to be a lot of oil out there that's going to show up on beaches for 10 years, 20 years," said R. Eugene Turner of Louisiana State University's Department of Oceanography and Coastal Sciences. "Tourists aren't going to like that at all."
The final 25% of the oil — the equivalent of four Exxon Valdez spills —- is of greatest concern to scientists. It is drifting 3,000 to 4,300 feet below the gulf's surface, in vast clouds of atomized droplets that could alter links in the chain of life.
This "dispersed" oil was broken into droplets, about the width of a hair, either when it shot at high speeds from the well's broken pipe or when it came into contact with the 1.8 million gallons of the controversial chemical dispersant Corexit.
The 5,000-foot depth of the leak exacerbates the mystery: Close to the surface, the Gulf of Mexico's warmth invigorates bacteria that have evolved to feed off natural oil seeps. But scientists are not sure what happens with oil-eating microorganisms in the darker, colder depths.
While one recent study showed that bacteria were slowly breaking down the oil, another found they were causing its "rapid decline." Last week, a third study said bacteria were mainly digesting natural gas that spewed from the well, but it didn't rule out that they were also consuming oil.
Kendra Daly, an ocean researcher at the University of South Florida, said the droplets could kill many plankton, a crucial component of the ocean food chain, possibly creating a cascade effect that could reduce the populations of other, larger species. Already researchers have found some evidence of oil harming plankton in an important spawning area off the Florida panhandle.
Susan Shaw, a marine toxicologist and director of the Marine Environmental Research Institute in Blue Hill, Maine, is among those concerned that the combination of the oil and dispersant is "more toxic than either alone" because the dispersants break down the lipid membranes of cells, allowing oil to enter organs more easily, she said.
But a study released in August by the Environmental Protection Agency showed that the dispersant-oil mix was no more toxic than oil alone. Critics say the tests were too limited. A better assessment, Shaw said, "will take decades."
A federal effort is underway to locate, measure and understand the effects of this remaining oil. In the meantime, independent researchers continue turning up surprises.
Some are relatively positive: Much of the oil appears to have stayed out of the Louisiana wetlands, a crucial hurricane barrier and fish nursery, thanks in part to vigorous oil-battling efforts at sea. A government spokesman recently estimated that just 550 acres of oil-contaminated marshes have been discovered. That pales in comparison with an average yearly wetlands loss of 9,600 acres in the state — the result of natural processes, oil industry dredging and flood control.
Other surprises are troubling: Earlier this month, University of Georgia researchers discovered layers of oil a few centimeters thick on the ocean floor, about 16 miles from the wellhead. Marine sciences professor Samantha Joye could not say whether the oil was from the BP spill. But she ruled out the possibility that it was from a natural seep.
POLITICS AND POLICY
The varied scientific conclusions have prompted a kind of political relativism: While environmental activists sound alarms — calling for tough drilling regulations and in some cases for an offshore drilling ban — some conservatives assert that the gaffe-prone Tony Hayward, ousted as BP's chief executive in the midst of the crisis, was right when he predicted the spill would have a "very, very modest" environmental impact.
A Financial Times/Harris Poll in July found that the spill had made 72% of Americans "more concerned" about water pollution. But now that the environmental drama will largely unfold in the vast obscurity of the sea, environmentalists are worried about their ability to rally an oil-dependent nation to their cause.
"It's kind of a challenge when the story is happening a mile underwater — and honestly, some of these impacts haven't even happened yet," said David Mizejewski, a naturalist with the National Wildlife Federation. "It's definitely something we're struggling with."
Even when images of oil-drenched birds were fresh in the news and BP was feeling the brunt of America's scorn, the massive spill failed to spur Congress to act on energy legislation. A sweeping, Obama-backed energy bill died in the Senate in July. Supporters pitched the bill as a way to reduce American dependency on fossil fuels, but opponents objected to its "cap and trade" emissions program.
A scaled-down bill, dealing largely with offshore operations, died in the Senate in early August, and it's doubtful that Congress will pass any major energy legislation before the November elections. Republicans, who tend to be more skeptical of vigorous changes to energy regulations, may retake one or both houses of Congress.
Thus it appears possible that the "greatest environmental disaster of its kind in our history" — as Obama put it in June — may not serve as a catalyst for major legislation.
That would set the BP spill apart from the Valdez spill of 1989 and the Santa Barbara oil spill of 1969, both of which eventually led to milestone environmental laws.
The difference is linked to the current partisan divide on environmental issues, said Mark Stoll, a professor of environmental history at Texas Tech University. Stoll also noted that lawmakers from the affected region have been among those most worried that energy legislation might kill their oil-reliant economy.
"I'm a little mystified by what the ramifications are going to be," Stoll said.
The Obama administration could end up making substantive changes to the business of offshore drilling with regulations that do not require Congressional approval. After the explosion, the administration scrapped the Minerals Management Service, the scandalously lax agency charged with oil-industry oversight, and replaced it with a Bureau of Ocean Energy Management, Regulation and Enforcement headed by Michael Bromwich, who prosecuted Marine Lt. Col. Oliver North during the Iran-Contra scandal.
The new agency has moved to enact more extensive environmental reviews of offshore projects, and last week it ordered permanent cement caps on more than 4,100 old and idle gulf wells. Obama also issued a deep-water drilling moratorium to buy time to determine how drilling could continue safely. The moratorium, which the administration estimates will kill up to 12,000 jobs, was widely criticized by Gulf Coast leaders.
Interior Department spokeswoman Kendra Barkoff said more rules are on the way.
"We are moving quickly and responsibly to raise the bar for the oil and gas industry's safety and environmental practices to prevent this type of disaster from happening again," Barkoff said in an email Saturday. "The oil and gas industry is having to meet new standards for everything from certification of well design and blowout preventers to planning for worst-case scenarios and being subjected to thorough environmental reviews."
During the spill, polls showed that the public disapproved of the president's overall handling of the crisis. But outside political races in gulf states, Obama's oil spill response hasn't been used much in broader attacks against him or Democrats as the nation heads toward midterm elections. In that sense, at least, the spill has not become "Obama's Katrina," as some predicted.
Alan Abramowitz, a political science professor at Emory University in Atlanta, said Republicans who famously chanted "drill baby, drill" at their last convention are in this case boxed in by their own convictions.
"It's been hard for Republicans to exploit this very much, because it doesn't really help their argument for deregulation and giving these corporations greater freedoms," he said.
For London-based BP, the world's fourth-largest company, the future holds one certainty: trouble.
With a battered image and depleted coffers, the company will be forced to contend with massive waves of civil litigation, the possibility of federal environmental fines and a criminal investigation by the Justice Department.
BP's market value has plummeted: As of Sept. 16, the oil giant had shed 34% of its market capitalization compared with its December 2009 value. BP has spent an estimated $8 billion on cleanup and compensation in addition to the $20 billion it deposited in an escrow fund to compensate for economic losses.
Company officials warned earlier this month that if new legislation hindered the company's ability to obtain new gulf drilling permits, it may not be able to fund the ambitious restoration projects it has promised for the region.
But pledges to "make this right" — repeated in the company's incessant national TV campaign — may be only one drag on BP's finances.
Roughly 300 civil lawsuits for economic damages and wrongful death await BP in a federal courthouse in New Orleans. The Justice Department signaled last week that it might sue BP for violating environmental laws. Fadel Gheit, a senior energy analyst for Oppenheimer & Co., has estimated that BP could face a maximum $2.9 billion fine from that lawsuit alone. The Center for Biological Diversity has filed a separate lawsuit seeking $19 billion in damages under the Clean Water Act.
FBI agents are examining whether BP officials misled Congress on how quickly the company could clean up a major spill. And an ongoing Coast Guard investigation suggests the BP Deepwater Horizon operation was marked by deferred maintenance and pressure to skirt safety measures in order to finish an overdue job. BP's internal investigation blamed a series of mechanical and human failures, but it also took aim at two rig contractors, Halliburton and Transocean Ltd.
The company will also have to acquit itself in the court of public opinion. In 2000, BP underwent an environmentally friendly rebranding, changing its logo to a green and yellow starburst and touting itself as "beyond petroleum."
But the Deepwater Horizon fire was only the latest of the company's oil-related disasters: In 2005, an explosion at BP's Texas City, Texas, refinery killed 15 workers and injured more than 170. Last month, BP agreed to pay a record $50.6 million fine for safety violations discovered at the plant by federal inspectors in 2009.
Along the Gulf Coast, the impact of the spill on humans often mirrors the situation on the water: To the casual observer, things seem fine on the surface. But beneath are roiling unknowns.
In downtown New Orleans, locals and tourists still dine on famous gulf delicacies. At Drago's Seafood Restaurant in nearby Metairie, the house specialty, charbroiled oysters, remains on the menu, though occasionally with oysters from Texas.
Two hours to the south, Dean Blanchard, owner of one of the largest shrimp businesses in coastal Grand Isle, La., said the oil spill has nearly driven him out of business. He is thinking about shutting down and moving to Costa Rica.
"People are scared to eat our product. I had a fisherman tell me his mama won't eat shrimp," said Blanchard, 51. "I've let go of 90% of my workforce.... Last August, shrimpers brought me 2 million pounds of crop. This year, they are bringing me next to nothing."
Thad Allen, the federal spill response chief, has called the seafood going to market "the most tested, and safest, seafood in the world right now." But many fishermen in Louisiana don't believe it.
Cvitanovich, the Louisiana oysterman, reported seeing oil ooze up from the bottom of Barataria Bay in August , while news outlets were reporting that much of the oil was gone.
"We are busting our asses to clean this place up, but we still see dirty oil and tar balls on the beaches and marshes," he said. "We don't know what is on the bottom, or what the future holds."
Many docks remain shuttered and some of the largest seafood processors in the state are preparing to import higher-priced product from Texas and North Carolina if necessary.
"We've got a sticky situation," said Errol Voisin, plant manager at Lafitte Frozen Foods. "This year I ain't got a clue what's going to happen."
A similar uncertainty extends to the charter fishing captains, who are struggling to lure big-spending sport fishermen back out on the water.
It extends to New Orleans officials, who wonder whether five months of bad press will scare away their lucrative catch of gourmands, revelers and conventioneers.
It extends to the oil industry. Last week, the American Energy Alliance issued a report claiming that "punitive" post-spill tax increases on oil and gas in Obama's 2011 budget proposal would wreak havoc on the Gulf Coast economy.
It extends to the beach towns, where it's not always enough to wish the gooey oil away. In Orange Beach and Gulf Shores, Ala., where tourism was down 50% this summer, officials used BP recovery money to invest in more than a dozen high-tech machines that comb the sands for tar balls at night.
"I have a strong belief that we will come back to normal in the next three to four years," said Mike Foster, vice president of marketing for the area's visitors bureau. "But I don't know what next year will bring. Because it's peaks and valleys, ups and downs."
Times staff writers Louis Sahagun in New Orleans and Ron White in Los Angeles contributed to this report.