20 Years After the Exxon Valdez: Preventing--and Preparing for--the Next Oil Spill Disaster [Slide Show]
The biggest oil spill in U.S. history sparked improvements in tanker construction and navigation technology, along with better crew training, but the danger remains
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20 Years After the Exxon Valdez: Preventing--and Preparing for--the Next Oil Spill Disaster [Slide Show]
- GUIDED PASSAGE: To avoid other oil tankers from running aground in Prince William Sound, two escort vessels now accompany each tanker as they pass through. The advent of the satellite-enabled global positioning system (GPS) since the Exxon Valdez crash now allows vessels with transponders on them to be tracked second-to-second anywhere in the world. But the main improvement—and what has led to far fewer mega-disaster spills costing billions in cleanup in recent years—has been in maritime culture and practices, says Bea. Having rested, trained crewmen at the helm, he says, should help assure that there will be fewer anniversaries of devastating oil spills to commemorate in the future. Exxon Valdez Oil Spill Trustee Council
- BREAK IT UP: So-called dispersants—chemicals that break oils into small particles—were used in the Exxon Valdez disaster and continue to see use worldwide today. In response to the accident, Exxon helped create COREXIT® EC9500A in the 1990s, a top dispersant deployed today. "Dispersants reduce the impact on shorelines, sensitive habitats, birds and wildlife," says Kathryn Venter, a spokesperson for Nalco Energy Services that makes the product.
Nevertheless, some environmentalists are not keen on dispersant use, Bea says. After treating a slick in the Gulf of Mexico with dispersants, for example, scientists later found that undersea currents brought the toxic oil into the Caribbean Sea. In this image, a responder sprays dispersant after a tanker spill near the Galápagos Islands in 2001. The Ecuadorian military, which led the operation, along with assistance from the U.S., determined that dispersant would mitigate onshore oil wash-up. NOAA - 09.jpg Floating tubes called booms help corral oil slicks around ships or prevent them from washing ashore, plus it makes it easier for skimmers to lap up the black gold. In this image, workers roll out a boom during the Cosco Busan fuel spill in San Francisco Bay in 2007. Depending on sea conditions and the kind of petroleum spill, booms come in a variety of heights and depths. For example, some have skirts that drape several feet under the waterline. In general, these containment devices have not changed appreciably since the Exxon Valdez accident, says Steve Edinger, the administrator of the Office of Spill Prevention and Response (OSPR) with the California Department of Fish and Game. U.S. Fish & Wildlife Service
- THE GOOP RISES TO THE TOP: We've all heard that oil and water don't mix; the saying goes for heavy crude as well as cooking oil. Reuptake devices called skimmers are used to slurp oil off of the top of seas and rivers, much of which can be reused. Today's skimmers have improved 10-fold over those available in the early 1980s and can recover 300,000 gallons (1,140 kiloliters) of oil in 72 hours, according to the Exxon Valdez Oil Spill Trustee Council's 2009 Status Report. Crucial, Inc., a Gretna, La.–based company that manufactures skimmers, has recently worked on a proprietary coating to place on the rotating belts, discs and drums within different kinds of skimmers that wick up four to five times the oil of those with conventional, noncoated surfaces. Crucial, Inc.
- BACK IN ACTION: Olive is expected to make a full recovery. When responders similarly cleansed otters after the Exxon Valdez despoiled Alaskan coastal areas, it took eight to 10 days to restore the otter's natural waterproofing; with Olive and the new thermal-reading technique, "it took just 53 hours," says Dave Jessup, senior veterinary scientist for the California Department of Fish and Game's Marine Wildlife Veterinary Care and Research Center. Sharon Toy-Choutka / California Department of Fish and Game
- OTTER LUCK: Using new thermal-imaging techniques to detect escaping body heat, rescue workers can see where oil and other impurities such as soap continue to prevent the otter's highly adapted fur from regaining to its normal water-repellency. The chart at right shows the temperature scale, with red and white colors showing areas of greatest heat loss. Olive is the first otter from the wild that the California Department of Fish and Game has tried the technique on. Did it work? [see the next slide]. Sharon Toy-Choutka / California Department of Fish and Game
- SCRUB DOWN: Oil clings to fur and feathers. Here, an otter found on February 21, 2009, that was soiled in a natural oil seepage event off of Monterey Bay, Calif., gets cleaned up at the Department of Fish and Game's Marine Wildlife Veterinary Care and Research Center in Santa Cruz. Nicknamed Olive, she has helped scientists test a new remediation technique, explained on the next slide [see Olive the Oiled Otter's Facebook page]. Otters stay warm in frigid waters by trapping air in their dense fur, which keeps the heat-robbing water away from their skin. Oil disrupts the interlocking barbs in the fur and makes it hard for the otter to groom the hairs back in place, leaving them vulnerable to their chilled environment. Even after washing with soap and water for two hours (otters get anesthetized prior to a cleaning session), oil, soap and salts can remain trapped in the fur, necessitating more rounds of washing. Sharon Toy-Choutka / Department of Fish and Game
- TARRED AND FEATHERED: An oiled seabird found after the massive oil spill. Though actual animal casualties will never be known, due to the large geographical area affected by the spill and bodies sinking underwater, estimates said that 40 percent of the pre-spill population of murres—common native black-and-white diving birds—died, according to the Exxon Valdez Oil Spill Trustee Council's 2009 Status Report. The council was formed to oversee restoration projects using the $900-million civil settlement reached with Exxon. Exxon Valdez Oil Spill Trustee Council
- OIL CAN'T HIDE: A new multispectral camera and thermal imager, mounted on aircraft that fly over a spill, can see the oil in ways the human eye cannot. "Oil gives off a different thermal pattern than non-oil," says Steve Edinger, the administrator for the Office of Spill Prevention and Response (OSPR) at the California Department of Fish and Game. This allows experts to accurately estimate the size of the spill, which they relay to a command center. Plus, by looking at wavelengths of light from the slick, "we can figure out the slick's thickness," says Judd Muskat, an environmental scientist at OSPR. This allows for the best deployment of cleanup resources, such as oil skimmers and booms (explained later in the slide show). This image shows the aftermath of the Cosco Busan bunker fuel spill. The tanker ran into the San Francisco–Oakland Bay Bridge in 2007. OSPR / Ocean Imaging
- FLOATING OIL WELL: The Sirius Star, a modern double-hulled tanker entered into service in 2008, made news recently when Somali pirates hijacked it and its precious cargo last November. As a very large crude carrier (VLCC), it can transport over two million barrels of oil, the equivalent of 84 million gallons (318,000 kiloliters) of crude. The Exxon Valdez was carrying 53 million gallons (200,630 kiloliters) when it wrecked. The Sirius Star is about 100 feet (30 meters) longer than the Exxon Valdez at 1,090 feet (330 meters). Even bigger ships, called ultra-large crude carriers, also roam the seas.
The United Nations has called for the phase-out of most single-hulled oil tankers, depending on weight class and when they entered service, by 2010. Double-hull tankers, as their name implies, provide two layers of material between oily cargo and the water outside. The case for double-hulling ships has been bolstered by reports like one from the U.S. Coast Guard in 1989 that concluded if the Exxon Valdez had a double-hull design, the amount of oil spilled might have been from 25 to 60 percent less. Some experts have questioned this because the gash was so deep that a second hull would most likely also have been breached. And double-hull tankers present safety issues of their own, says Robert Bea, a professor of civil engineering at the University of California, Berkeley. The ballast for these ships is often sandwiched between the two hulls; in the event of a hull breach, the ship may lose its stability and turn over on its side, Bea says. U.S. Navy - BREACH OF FAITH: The hull of the oil supertanker Exxon Valdez was ripped open when it ran onto Bligh Reef in Alaska's Prince William Sound on March 24, 1989. 10.8 million gallons (40,900 kiloliters) of oil poured forth, about 20 percent of the ship's hydrocarbon cargo. The biggest spill in U.S. history, the event captured the public's attention and galvanized congressional lawmakers into writing the 1990 Oil Pollution Act. The legislation beefed up the nation's ability to prevent and respond to oil spill disasters. USGS
