Gulf oil spill: A Q&A on one of the nation’s worst environmental disasters

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The British Petroleum well in the Gulf of Mexico that’s been spewing at least 210,000 gallons of oil a day since April 22 isn’t so much a spill as an eruption of crude, natural gas and mud.

Government and industry efforts continue to focus on stemming the leaks located 50 miles off the Louisiana coast and keeping a spreading blob of oil from the most environmentally sensitive areas onshore. But officials are certain that recovery from the disaster will be both long and costly.

Below, in a question-and-answer format, is an overview of what’s happened so far during one of the nation’s worst environmental mishaps and the outlook for the coming weeks and months.

Q: How did this happen?

A: The formal investigation of the accident has barely begun, but it appears that it began when an explosive mix of gas, oil and mud blew out of the well under extreme pressure and surged nearly a mile to the floating Deepwater Horizon rig at the surface. The failure could have involved a number of pieces of equipment deployed near where the well entered the sea floor, but it’s certain that a device called a blowout preventer -- meant to crimp the well closed during an emergency -- didn’t work.

Gas reached generators and other equipment running on the rig, producing a massive explosion and fire that eventually caused the floating platform to sink and ruptured piping to leak. At first, much of the leaking oil burned and it wasn’t until after the rig sank that the extent of the leak gradually became apparent. Eleven of 126 crewmen working on the rig are thought to have died in the initial explosion.

Q: What happened to the survivors of the rig’s crew? What did they see?

A: Although a number sustained burns or broken bones from leaping from the platform to the sea, all reached shore safely and only a few had to be hospitalized. Crew members interviewed by various media outlets since reaching shore have mentioned feeling two heavy thumps or thuds shake the platform, hearing a hissing sound, smelling petroleum and seeing mud and oil showering onto the deck from the rig’s derrick just before the explosions began.

Q: Has this sort of accident happened before? Could this be the worst oil spill in history?

A: There have been a number of major oil spills from offshore platforms, including the 1969 blowout of a Union Oil exploratory rig off Santa Barbara, Calif., that spilled 3.4 million gallons and became a rallying point for environmentalists. The 1979 blowout of an exploratory well, Ixtoc 1, in the Gulf of Mexico’s Bay of Campeche released an estimated 14.7 million gallons and took nine months to control; it is considered the second-worst oil spill behind only the Iraqi army’s destruction of hundreds of wells near the end of the first Persian Gulf War in 1991. The U.S. record is more than 10 million gallons released by the Exxon Valdez in Alaska in 1989.

Deepwater Horizon’s place on the list depends on how long it takes to stop the flow. So far, it’s released about the same amount as the Santa Barbara accident but far less than the estimated 8.7 million gallons of oil spilled into the Gulf and its estuaries by rigs and storage tanks damaged during Hurricanes Katrina and Rita in 2005.

Q: How many oil and gas rigs are operating in the Gulf? How many are in such deep water?

A: There are about 3,500 active wells in the Gulf. There are about 120 mobile offshore floating rigs and 50 fixed rigs able to operate down to depths of 10,000 feet below the sea surface; oil-industry analyst ODS-Petrodata says about two-thirds of the mobile rigs and half of the fixed platforms are working. Several offshore rigs near the site of the accident were shut down as a precaution in late April.

Q: Has the government stepped up inspections of the other rigs to make sure this doesn’t happen again?

A: Federal officials with the Minerals Management Service issued a number of safety alerts to all offshore operations in the Gulf and special inspection teams went out in the past week to visit 30 wells of particular concern. Interior Department officials said no major deficiencies were found. As investigations and congressional hearings on the accident continue, additional safety requirements for offshore wells are likely to be proposed.

Q: Who has responded to try to keep the spill from spreading?

A: The response has been a combined effort between workers and contractors of British Petroleum, which holds the lease for the well and the destroyed rig, and numerous federal agencies, including the U.S. Coast Guard, the National Oceanic and Atmospheric Administration, the Environmental Protection Agency and Interior, as well as many state agencies and volunteer groups working to protect shorelines.

BP’s efforts have mainly been toward using underwater robots and other devices to stop the leaks and clean up near the well with skimmer ships, while the Coast Guard has taken the lead in coordinating the application of hundreds of thousands of gallons of chemical dispersants, the burning of small patches of oil slick and the placement of containment booms by an armada of more than 256 vessels. More than 8,000 people are involved in the recovery work and more are planning to protect other potentially endangered coasts. About 2,500 volunteers also have been trained.

Q: What is the estimated cost of the cleanup? Who is going to pay the bill?

A: Damage specialists initially put the cleanup cost at between $3 billion and $7 billion. A growing list of lawsuits suggests that liability for the spill, injuries and economic damage _ and uncertainty about how long leaks will continue _ could push the tab much higher. BP officials have pledged to pay “all necessary and appropriate cleanup costs” as well as “legitimate and objectively verifiable” damage claims, but some analysts have questioned whether the self-insured company and its partners can really cover all the expenses.

Q: How long might the effects of the oil spill be felt? What happens to oil that’s beneath the surface?

A: Some of the oil and residue are likely to remain in the silt and sand of the Gulf for decades. Wildlife and human-health officials are more concerned about how much of the oil will wind up passing through microbes and plankton up the fish, marine-mammal and bird food chains. The good news so far is that most of the seafood-harvesting region of Louisiana hasn’t been affected, although there are signs the spill is starting to move in that direction.

Government scientists are starting to measure and track what’s happening with oil beneath the surface, but many unknown factors will determine how enduring the impact will be, including the ultimate amount of oil spilled, how well dispersants and barriers work and where the oil floats.

The Gulf’s warm air and water temperatures, marshes and sandbars can help degrade oil faster, say, than it has in Alaska’s Prince William Sound. The Ixtoc spill left relatively little lingering damage in the eastern Gulf. And while a storm system in the first week of the spill hampered containment efforts, experts say the expected arrival of one or more tropical storms in the Gulf could help dissipate the oil.

Q: Will the section of the Gulf closest to the spill become a “dead zone” because of the oil and chemicals used to break it up?

A: Marine biologists have been talking about a “dead zone” near the mouth of the Mississippi for many years, caused by agricultural runoff that nurtures algae but starves the water of oxygen.

Lisa Suatoni, a senior ocean scientist with the Natural Resources Defense Council (NRDC) who is monitoring the spill, said she’s “pretty sure the toxic qualities of the spill won’t cause its own version of a dead zone (farther out in the Gulf). Many of the effects will be sub-lethal, not acute.”

Q: What might be the impact of the spill if large quantities of oil are moved great distances by the Gulf Stream?

A: Some of the grimmest scenarios painted by some academic experts on spills and currents have the spill drifting south in the “Loop Current” that circles the middle of the Gulf and eventually mixes with another current near the tip of Florida to become the Gulf Stream. That could spread the oil slick in the coral reefs and island of the Keys and on north as far as Cape Hatteras, N.C., where the current moves farther away from land.

Government scientists say they don’t know if this will happen, but state and federal officials in Florida have been making plans on how to react if it does.

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Q: What factors could influence the oil reaching the Florida Keys and Atlantic beaches?

A: Again, one issue is how much oil there is to float away. Government scientists are working to understand how the oil broken up by chemicals is behaving. Slicks on the surface tend to evaporate and sink over time. Although oceanographers know generally how the Gulf Stream moves, it wiggles and wobbles and even seemingly disappears at times. Weather at sea is too uncertain to forecast where the oil will spread more than a few days ahead. Winds, hurricanes and cold fronts are among the many things that could keep oil near shore or break it up.

Q: What are tar balls? How dangerous are they to the environment?

A: Weathering, sunlight, even salt water itself eventually turns globs of oil into hard, asphalt-type material fairly quickly. These tar balls linger for decades -- they’re still all over Santa Barbara shorelines -- but any toxic material inside them is basically inert and won’t hurt humans if they don’t handle them too much or eat them.

Q: If you scooped up a glass of the floating oil foam and drank it, what would happen?

A: “Drinking oil is a bad idea,’’ said Gina Solomon, a public health specialist with the NRDC. Most of what’s known about this comes from documenting suicides and attempts that involved drinking gasoline. Petroleum is corrosive to the esophagus and stomach, and swallowing even a little would make you vomit. That would put small bits of oil into the lungs and likely lead to respiratory collapse.

Q: Assuming less-direct exposure, what health effects might humans face from the oil spill?

A: The federal Centers for Disease Control and Prevention lumps the several hundred chemical compounds found in crude oil as “total petroleum hydrocarbons” and says their leading effect is on the nervous system, typically producing dizziness or headache when fumes are inhaled or crude comes into extended contact with the skin, mouth or eyes.

There are several known and even more suspected carcinogens in hydrocarbons, but most health experts say the biggest immediate health threat from this spill inshore is to people with respiratory disorders and pregnant women. But they caution anyone who might do beach or wildlife cleanup to wear gloves, protective clothes, eyewear and boots and be sure to keep contaminated items out of homes.

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Q: Should we expect oil and gas prices to increase because of this spill?

A: They’re already going up and will go up more this summer as driving increases and the economy continues to recover. But energy experts say there’s no link to the spill -- at least, not so far. Deepwater Horizon’s well, called Macondo, wasn’t a producing well yet. The crews were actually preparing to cap it off for the time being.

The Gulf does account for about 40 percent of U.S. production, but most of the producing rigs are far south and west of the spill site, away from the direction the sheen has moved so far.

Still, if the leaking continues for many weeks and different wind patterns push the oil into those production zones -- or if it affects shipping and refining capacity along the coast -- there could be an effect on oil supplies. Longer term, new scrutiny of the safety of offshore, deepwater drilling could impact the ability of oil companies to develop new oil fields in the Gulf, off California and the East Coast.

Q. How might the oil spill affect different ecosystems along the Gulf coast?

A. Sandy beaches are the easiest ecosystem to clean up. The oil comes ashore, is tossed around by the waves, mixes with sand and becomes tar balls that can be picked up. When it gets into marshes or wetlands it is more problematic, because they are low-energy ecosystems with less wave action. Oil gets between individual marsh plants and sticks to them, and also soaks deep into the marsh’s bottom, where it can stay for years.

Mangroves also are difficult to clean up because their tangled roots make it impossible to use cleaning equipment, and chemical dispersants can’t be used because they also kill the mangroves.

Q. How might sea turtles, with a nesting season starting May 1, be affected by oil in the Gulf?

A. Sea turtles breathe at the ocean’s surface, so when they come up to breathe in an oil slick, they’re inhaling oil fumes, covering their face in oil, and often getting oil in their stomach and lungs. Rehabilitators who have dealt with oiled sea turtles said that the animals were entirely covered in a thick, sticky tar, including the insides of their mouths. All the sea turtle species in the Gulf of Mexico are at risk, including the critically endangered Kemp’s ridley turtles that live primarily in the Gulf of Mexico, loggerhead turtles, green turtles, and hawksbill turtles.

Sea turtles expected to start arriving on the beaches of Collier County to lay their eggs sometime next week, when the Gulf temperature rises to 81 degrees. If there is oil on the beach when the turtles crawl up to lay their eggs, they’d have to crawl through it. If it got on the eggs it could affect the baby turtles inside, and once the turtles hatch, if they have to crawl or swim through it, it could affect their survival.

_ Staff writer Katy Bishop contributed to this report

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