Exxon Oil Spill Technology Advances from the Valdez Cleanup

EXXON OIL SPILL TECHNOLOGY ADVANCES FROM THE MLDEZCLEANUP Richard R. Lessard, Gregory DeMarco, and Roger C. Prince Exxon Research & Engineering Company 180 Park Avenue Flor ham Park, New Jersey 07932 Jeny Canevari G. P. Canevari and Associates 104 Central Avenue Cranford, New Jersey 07016 ABSTRACT: The Exxon Valdez oil spill in 1989 was the largest marine oil spill in U.S. history. It triggered a massive cleanup and accelerated major changes to the U.S. structure for combating oil spills. It also led to a number of successful new programs within Exxon and industiy aimed at reducing incidents, minimizing spillage of oil worldwide, and improving the capability to respond in the event of a spill. Exxon's response effort is widely acknowledged as the largest peacetime industrial mobilization ever in the United States and possibly in the world. Exxon immediately accepted responsibility and committed resources and personnel to clean up the environment affected by the spill The Valdez spill is the most studied ever. The cleanup involved the use of technology not previously applied to large spills. Many of these applications are now the subject of ongoing international research programs aimed at improving the ability to respond. This paper, written by several Exxon scientists who conducted technical studies in support of the cleanup, summarizes many of the technical learnings and advances that came out of the spill, and subsequent research studies with emphasis on how these apply to today's spills. This paper discusses only the response and cleanup. Exxon also initiated a number of programs to mitigate impacts on people, communities and wildlife affected by the spill. its regrets, and committed to clean up the spill. After a short transition period, Exxon took over management of all response operations working under the direction of the U.S. Coast Guard Federal On-Scene Coordinator (FOSC). Though this spill still remains the largest in U.S. history to the marine environment, the amount spilled ranks it relatively low on the list of all-time worldwide spills—number 53 according to the latest data summary issued by Cutter Information Corp. (Cutter Information, 1998). What made the Valdez spill noteworthy and led to such a massive response effort was the extent of shoreline impact (over 1,300 miles/2,000 km) and the environmentally sensitive area in which it occurred. Exxon personnel arriving on the scene had four priorities all to be worked concurrently (Harrison, 1991). The highest and most immediate priority was to off-load 1 million barrels (about 160,000 tonnes) of crude which remained on the Valdez—about 80% of the original cargo. Though the vessel was precariously balanced on Bligh Reef, Exxon experts worked closely with Coast Guard personnel to successfully transfer all the cargo to other tankers. This was later viewed as a major achievement, particularly because it occurred over an 11-day period without injury or further loss of cargo despite 15-foot (5-meter) tides and a major storm. The next priority was identification and protection of sensitive environmental areas. All parties involved, including fishermen, developed a priority listing of valuable resources. At the top of the list were salmon hatcheries. The early boom deployment focused on the hatcheries and important salmon streams and the oil was kept out of those areas. This was another very positive achievement. The third priority was on removal of oil from the water. For this priority there were disappointments. Overall, only about 60,000 barrels (9400 tonnes) of emulsion containing about 25% oil were collected by mechanical skimmers. The fourth priority was the removal of oil from the shorelines. This paper focuses on the third and fourth priorities. Summary of the spill On March 24, 1989, the Exxon Valdez, a 987-foot (300-meter), state-of-the-art tanker carrying 1.25 million barrels (196,000 tonnes) of Alaska North Slope (ANS) crude oil went aground on Bligh Reef in Alaska's Prince William Sound. The grounding opened 8 of the vessel's 11 cargo tanks and 3 of the 5 ballast tanks, releasing about 260,000 barrels (41,000 tonnes) of ANS into the water, almost all of it within the first few hours. The site of the spill was very remote, far from major population centers and only accessible by boat and aircraft. Consistent with the area oil spill contingency plan, the initial response was carried out by Alyeska Pipeline Service Company (operator of the marine terminal at Valdez) and by the U.S. Coast Guard. Exxon has very limited operations in Alaska. However, company personnel began arriving from its main center of operations on the Gulf Coast of Texas, some 3,000 miles (5,000 km) away, on the first day of the spill. Exxon acknowledged responsibility for the spill, expressed Response to the oil on the water Spill response experts agree that spills which have had obvious and significant biological impacts have always involved near- 357 Downloaded from http://meridian.allenpress.com/iosc/article-pdf/1999/1/357/1752190/2169-3358-1999-1-357.pdf by guest on 21 December 2021 Robert J. Fiocco R. J. Fiocco Associates 77 Pine Grove Avenue Summit, New Jersey 07901 358 1999 INTERNATIONAL OIL SPILL CONFERENCE 1 OIL MOVING ONSHORE OR 1 INTO CRITICAL AREA(S) 1 1 Yes No IS PHYSICAL CONTROL AND RECOVERY FEASIBLE L I IS ACTION REQUIRED OR DESIRED Y€ >s 1 Yes 1 No No i I 1 MONITOR | MOVEMENTS IMPLEMENT ARE CONTROL/RECOVERY ACTIONS ADEQUATE I Yes No or Partially 1 J CONTINUE ACTIONS CAN OIL TYPE AND CONDITION BE CHEMICALLY DISPERSED 1 Yes IS A DISPERSION OPERATION POSSIBLE \· t 1 No 1 TREAT ONSHORE N 1 Yes No i WILL IMPACTS ASSOCIATED WITH CHEMICAL DISPERSION BE LESS THAN RESULTING WITHOUT CHEMICAL DISPERSION No I 1 REQUEST APPROVAL FOR USE OF DISPERSANTS USING ATTACHED PROCEDURE Yes WILL VULNERABLE RESOURCES OR HABITS BE ADVERSELY IMPACTED WITHOUT DISPERSANTUSE Figure 1. State of Alaska dispersant-use decision matrix in 1989. on the part of regulators as to whether or not oil would be dispersible. The result is Corexit 9500, a new product which has now been demonstrated effective on heavy, weathered and emulsified oils in the laboratory, in field tests and on actual spills. Corexit 9500 can disperse even heavy bunker oils provided they are still fluid enough to spread (Fiocco and Lessard, 1997; Lessard et. al., 1998). The key to the effectiveness of this product is the use of solvents that readily penetrate and remain in the oil film ("enhanced self-mixing") resisting extraction by sea water which enables the surfactants to carry out their function at the oil/water interface. Solvents used in earlier products, such as Corexit 9527, are more water soluble and can be extracted out of the oil, given sufficient time. This is not a problem for fresh or relatively unweathered oils because the film is loose and surfactants are more mobile and reach the interface very rapidly. But it can become an issue as the oil film viscosity rises and the rate of diffusion to the interface becomes slower and takes longer to occur. The key milestones in demonstrating the effectiveness of the new product were lab studies by Battelle Ocean Sciences in 1996 and the North Sea trials conducted by the U.K. National Environmental Technology Centre in 1997. In the Battelle tests, using weathered oils from the Morris J. Berman spill in Puerto Rico and samples of heating oil from one of Florida Power and Light's electrical plants, scientists demonstrated that Corexit 9500 maintains effectiveness at viscosities as high as 80,000 cP (see Figure 2). In the ensuing North Sea trials, significant quantities of Downloaded from http://meridian.allenpress.com/iosc/article-pdf/1999/1/357/1752190/2169-3358-1999-1-357.pdf by guest on 21 December 2021 shore or intertidal accumulations of oil (Lewis and Aurand, 1997). A successful response is one that prevents or minimizes the amount of oil reaching sensitive areas, preferably by removing it from the water but, failing that, by dispersing it into deep water where its impact can be less damaging to the environment. This position is supported by many international organizations, including the National Research Council (Butler, 1989; NRC, 1989), the International Maritime Organization, and the United Nations Environment Programme (IMO, 1995). The most critical time period during an oil spill response is early in the spill while the oil is still on the water. During that early period, oil is in its most confined and thickest state. All response options, be they mechanical, dispersion, or burning, have highest efficiency and effectiveness when applied as soon as possible after the spill has occurred. In the case of the Valdez, a number of factors worked against a prompt response. Mechanical equipment was for the most part unavailable in the first few days because the barge used for storage and transport of this equipment was under repair This left chemical dispersion as the only practical option. In 1989, Alaska was the only state in the United States to have defined pre-authorized zones where dispersants could be deployed at the sole decision of the FOSC without need for approval by the Environmental Protection Agency (EPA) or the state of Alaska (Lessard and DeMarco, 1998). The FOSC was merely required to inform these parties of the decision as soon as possible after making it. However, the dispersant-use decision matrix for Alaska (see Figure 1) contained a step requiring verification that the oil type and condition made it dispersible before granting approval for widespread use (Fräser, 1989). Paradoxically, the state plan also stated that if dispersants were to have maximum benefit, immediate use would be required. In the Valdez incident, the local FOSC elected to request field tests to verify that the oil was dispersible before authorizing full-scale deployment. Several large-scale field tests were needed to confirm effectiveness. By the time that permission to use dispersants was obtained, some of the oil had spread outside the pre-authorized zone and, more importantly, a major storm arose and the window of opportunity was closed. The storm churned the oil and water into emulsion, distributing it widely over Prince William Sound and the Gulf of Alaska. At about the same time the National Research Council (NRC) Committee on the Effectiveness of Oil Spill Dispersants issued its final report following several years of study. It concluded that under proper conditions, dispersant use can result in a net benefit to the environment and recommended that dispersants should be considered as a potential first response option to oil spills, along with other response options. Had this report been issued earlier, it is possible that the Coast Guard might not have been as hesitant to approve immediate dispersant application, though this is speculative. On hearing of the delay in approving dispersants for the Valdez spill, Dr. James Butler, head of the NRC committee, indicated that this would have been an excellent opportunity for dispersant use because the added energy provided by the storm would have helped disperse the oil into the water and then tidal currents would have carried it to the open ocean where it would be still further diluted, rendering it much less harmful than the untreated slick (Davidson, 1990). Dispersant advance triggered by Valdez experience. The root cause issue that resulted in loss of the dispersant window of opportunity in Alaska was uncertainty about the dispersability of ANS crude. Subsequent to the Valdez incident, Exxon revised its ongoing oil spill R&D program priorities. Because of the Valdez experience, the highest of these priorities was the development of a dispersant formula so effective that it would remove indecision EXXON VALDEZ/RECOVERY 359 Prior Limit of Effectiveness COREXIT 9500 COREXIT . Disp/Oil Ratio 1:25 9527 I ^ ^ 20000 Battelle Ocean Sciences 30000 J 40000 L 50000 60000 70000 80000 V I S C O S I T Y (cP) Figure 2. Corexit 9500 extends the "window of opportunity." oil (ANS crude, North Sea Forties crude, and IFO-180 bunker oil) were weathered at sea for up to 55 hours, creating emulsions. The Corexit 9500 was demonstrated effective on all three oils, though effectiveness dropped off some on the second day for the IFO180 (Lewis et aL, 1998). Dasic NS was also effective on the lighter Forties Blend, even after the oil had been on the sea for over 40 hours. The window of opportunity has now been shown to be sufficiently broad that today's regulators have less concern about whether or not dispersants are going to be effective. Prompt application of dispersants in several recent U.S. spills in the Gulf of Mexico underscores the confidence that FOSC's now have in the ability of dispersant products to effectively disperse oils, without need for time-consuming field tests. Shoreline cleaning After the oil had impacted the shorelines of Prince William Sound and the Gulf of Alaska, Exxon, working with government and local groups, committed itself to clean these shores. This cleanup was a mammoth task complicated by geographical and ecological factors. At its peak in 1989, the effort involved over 11,000 people. As a first step, nearly 3,600 miles (6,000 km) of shoreline were surveyed by assessment teams (Shoreline Cleanup Advisory Teams or SCATs) that generated geomorphological, biological, archaeological, and oiling information that led to sitespecific treatment plans (Teal, 1991). Most of the shoreline oiling outside of Prince William Sound was very light, involving scattered mousse and tar balls which could be cleaned by manual techniques (shovels, buckets, and hand-held tools). In Prince William Sound, however, the oiling was more severe and the heavily oiled shorelines required water washing to dislodge the oil. The consensus of all parties involved (14 organizations), as well as of oil spill consulting experts, was that it was imperative to remove bulk oil from the shorelines to minimize the potential for the beached oil to refloat and affect additional shorelines or wildlife beyond that already impacted. Ultimately, all of the impacted shoreline was cleaned to varying degrees. The principal method on the 240 miles (400 km) of moderately to heavily oiled shorelines was to wash the oil from the rocks, using cold or warm water, or both. The oil was flushed into the Sound where it was contained by booms and removed by skimmers for subsequent separation and treatment. Some of the more aggressive clean-up techniques, such as hot water washing, have been criticized, but it must be realized that intertidal biota had already been impacted by the oil and all parties involved in the decision to clean the beaches agreed that it was critical to remove as much oil as feasible expeditiously to minimize further impact and accelerate the recovery process. The safety of the workers cleaning the beaches was of paramount importance. Therefore, it was agreed that operations would need to end by mid-September because of the onset of winter storms. Because this meant a relatively short cleaning window, Exxon initiated a number of supporting technical studies to identify innovative techniques to accelerate the cleaning process. To do this, the company re-assigned many of its scientists to special programs aimed at supporting the cleanup. Some of those re-assigned had prior experience in oil spill technology. These programs lasted until 1991 and eventually evolved into a focused R&D effort which has continued throughout the 1990s. Mechanical engineering. The shoreline cleaning effort was slow and tedious, involving thousands of workers with hoses on the beaches. One innovation conceived for accelerating cleanup stage were workhorse pieces of equipment called maxi-barges. These custom-built barges each had a crew of 50, about 10,000 feet of boom, several oil skimmers, fuel and storage tanks, generators, and water heaters. Many were also provided with unique equipment to treat shorelines not readily accessible by foot. Called an omni boom, this was an adaptation of a system normally used for pumping concrete on construction projects to which Exxon engineers attached a specially designed shower head which could deliver large amounts of water under pressure to rock faces and cliffs. These booms were ideal for the rugged rocky shorelines commonly found in Prince William Sound and helped teams safely clean hard-to-reach areas. Bioremediation. A second innovative application used to accelerate cleanup in Alaska was bioremediation. The concept involves stimulation of indigenous oil-degrading microbes through the addition of fertilizers to speed up the rate of natural degradation of the oil. This is a process which is only helpful when there is a nutrient deficiency. Exxon spent over 10 million dollars in collaboration with the U.S. EPA on bioremediation application during 1989 through 1991. A major contribution by Exxon scientists was the development of unique analytical approaches to track the degradation rate by comparing the falling levels of components to the concentration of a non-degradable marker called hopane. Studies confirmed that addition of nutrient accelerated the removal of hydrocarbon from Alaska beaches by Downloaded from http://meridian.allenpress.com/iosc/article-pdf/1999/1/357/1752190/2169-3358-1999-1-357.pdf by guest on 21 December 2021 10000 360 1999 INTERNATIONAL OIL SPILL CONFERENCE Chemical cleaners. The last shoreline cleaning advance to come out of the Valdez spill was the use of chemical cleaners to accelerate the removal of oil from beaches by helping to loosen the oil. Realizing that the Alaska North Slope crude on the shorelines was weathering rapidly with time making removal by water wash more difficult and time consuming, Exxon scientists sought a low toxicity chemical product which could loosen the viscous oil and expedite the cleanup. It was felt that such a product would also allow the continued use of colder water making it easier to remove the oil without having to resort to higher temperature water. Initially, the preference was to identify an existing product that would serve this purpose. However, after screening more than 100 available formulations, none was found that met all the criteria established by the authorities: high effectiveness, low toxicity, and not a dispersant. Many existing products were toxic because of aromatic solvents. Low toxicity cleaners were generally ineffective. Some products that were effective also dispersed the removed oil as fine droplets and could not be recovered. Exxon scientists then embarked on a special program to develop an entirely new agent that would satisfy the three requirements. In a period of only a few months, the product now marketed as Corexit 9580 was formulated, and proven in both laboratory tests in New Jersey and large-scale field tests on the shorelines in Alaska (Fiocco et aL, 1991). Corexit 9500 resolved all the shortcomings of the available cleaner products cited above. After these tests and considerable toxicity evaluation, Exxon was certain that Corexit 9580 would be an important tool for improving the efficiency of beach washing without the need to resort to high water temperature. However, government authorities never approved widespread use of Corexit 9580 in Prince William Sound out of concern that it was really a dispersant. Chemical beach cleaners have since been shown effective and safe tools for cleaning oil-impacted shorelines. Used in subsequent spills after the Valdez, Corexit 9580 has more than lived up to the original expectations. It was tested by NOAA on beaches impacted by the Morris J. Berman spill in Puerto Rico (Michel and Benggio, 1995), and has been used to effectively and safely clean up after spills in Texas and in Canada. The Canadian government's own labs in Ontario have not only confirmed that it is the most effective cleaning agent available, but that it is also the least toxic to rainbow trout-the Canadian toxicity test species (Canevari et aL, 1994). In fact, this product, developed for but not used in the Alaska cleanup is now the only beach cleaner that is permitted to be used on shorelines in Canada. The new cleaner has also proved to be a major advance in the cleaning of vegetation in oiled habitats. Mangroves are ranked as one of the most sensitive marine environments. If mangroves are oiled, and no further action is taken, there is a high probability of mortality to the trees. One of the ways that viscous spilled oil can kill mangroves is by covering their breathing ports, called lenticels, and prevent them from obtaining oxygen from the atmosphere. Tests were conducted on oiled mangrove trees by Professor Howard Teas, University of Miami, that showed that Corexit 9580 could remove oil from the air-breathing pores without damaging them. The period of time after oiling for the cleaner to be effective was also established (Teas et aL, 1993). Similarly, a major research program conducted by LSU showed that Corexit 9580 could effectively remove oil from oiled marshgrass and accelerate recovery of the plants (Pezeshki et aL, 1995). After positive greenhouse studies, extensive field tests were conducted. Two years of field studies involving salt, brackish and fresh water species of marshgrass produced a complete data base matrix to support this remediation method. The study involved oiling with more stressful oils such as heavy fuel oil as well as South Louisiana crude oil. Downloaded from http://meridian.allenpress.com/iosc/article-pdf/1999/1/357/1752190/2169-3358-1999-1-357.pdf by guest on 21 December 2021 3-5 times as compared to reference beaches that were not bioremediated (Bragg et aL, 1992). Over 70 miles (120 km) of shoreline were remediated in 1989 with dramatic results. Bioremediation was used only after bulk oil had been first removed. Since the Valdez cleanup, bioremediation has been extensively studied and used to speed up the removal of oil on other spills, particularly on the Sea Empress spill. The many studies carried out— by EPA in the United States, by CEDRE in France, by SINTEF and Environment Canada in Norway, and by AEA in the United Kingdom— have confirmed the Alaska findings. The use of bioremediation on the Valdez spill was the most thoroughly studied application ever, giving impetus to the use of this technique to speed up the removal of the oil from shorelines. It continues to be an attractive option for speeding up the visual restoration of the impacted shorelines. The role of bioremediation in accelerating biological recovery, however, is not well understood. Oil-fines interaction (OFI). Another advance from the Valdez cleanup was an improved understanding of how natural cleanup proceeds after shoreline oiling. Natural processes have long been recognized as effective in the removal of spilled oil from the environment. This was the case in Alaska. Much of the remediation which was observed was clearly a result of natural forces. Data collected at 16 monitoring sites in Prince William Sound showed significant continued reductions in shoreline oil content during the winter of 1989-1990 well after cleaning operations had ceased. On high and moderate energy beaches, this natural cleaning appeared to be a result of wave action associated with winter storms. However, observations from lowenergy areas showed similar removals without the benefit of the wave action. This generated interest in better understanding the mechanisms by which oil is released from low energy shorelines. Exxon scientists worked with specialists who had previously studied beach cleaning phenomena, and confirmed a new mechanism for shoreline cleaning not previously reported in the literature. Interactions between fine mineral particles, such as clay, with polar components in oil residue were found to play an important role by facilitating the mobilization and removal of both surface and subsurface oil (Jahns et aL, 1991). These interactions result in flocculated aggregates of solids-stabilized emulsions in which very fine oil droplets are coated with microsized mineral fines and surrounded by sea water (Bragg and Yang, 1995). In this form, the oil no longer adheres to the sediment surfaces and it can be removed even under low energy conditions. The large available surface area of the flocculated oil also promotes its eventual biodegradation by indigenous microorganisms. This is now viewed as a major advance in our understanding of one of the primary ways that shorelines clean themselves following an oil spill. Subsequent to the Valdez cleanup, this mechanism was confirmed for other spills where oil removal also occurred at low energy conditions. At the Second International Oil Spill Research and Development Forum in London in 1995, oil spill experts from around the world collectively expressed high interest in this phenomenon and rated the continued improved understanding of the role of OFIs in shoreline cleaning as a top research priority. It was very effective in accelerating shoreline restoration following the Sea Empress spill in 1996 (Lee et aL, 1997). The ITOSS project in Svalbard, Norway (carried out by SINTEF and Environment Canada) has further clarified the phenomenon of OFI, building on the learnings of the Valdez cleanup to further explore how this knowledge can be turned into a pro-active technique for accelerating natural cleaning through addition of fine minerals (Sergy et aL, 1999) EXXON VALDEZ/RECOVERY The studies of ecologically important fresh, brackish and salt marsh grass species indicated the oiling caused severe change in leaf gas exchange functions unless the plants were cleaned with the shoreline cleaner. Application of the shoreline cleaner Corexit 9580 improved stomatal conductance and transpiration rates, gross fixation of atmospheric C0 2 -C and the regeneration of the new shoot. Cleaning with Corexit 9580 clearly accelerated recovery as evidenced by the regeneration and gross fixation of atmospheric C0 2 -C. Summary References 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. Biography Dr. Dick Lessard heads Exxon's oil spill R&D program. He is a noted lecturer on dispersants and has given presentations to government agencies around the world. During the Valdez cleanup, Dr. Lessard coordinated many of the scientific studies which underpinned the cleanup strategies proposed by Exxon. 15. 16. Bragg, J.R.; Prince, R.C.; Wilkinson, J.B.; and Atlas, R.M; Bioremediation for Shoreline Cleanup Following the 1989 Alaska Oil Spill; Exxon Company U.S.A.; Houston, TX; 1992. Bragg, J.R. and Yang, S.H.; Clay-Oil Flocculation and its role in Natural Cleansing in Prince William Sound Following the Exxon Valdez Oil Spill; Exxon Valdez Oil Spill: Fate and Effects in Alaskan Waters, P. G. Wells, J. N. Butler, and J. S. Hughes (editors) 1995. Butler, J.N.; Using Oil Spill Dispersants on the Sea; Proceedings of the 1989 Oil Spill Conference Proceedings; API; Washington, D.C.; 1989. Canevari, G.P.; Fiocco, R.J.; Lessard, R.R.; and Fingas, M.; Corexit 9580 Shoreline Cleaner: Development, Application, and Status; ASTM Symposium on Use of Chemicals in Oil Spill Response; ASTM STP 1262; Philadelphia, PA; 1994. Cutter Information Corp.; International Oil Spill Statistics, 1997; Arlington, MA; 1998. Davidson, A.; In the Wake of the Exxon Valdez; Sierra Book Clubs; San Francisco, CA, 1990, Pg. 44. Fiocco, R.J., Canevari, G.P., Wilkinson, J.B., Jahns, H.O., Bock, J., Robbins, M., and Markarian, R.K.: Development of Corexit 9580—A Chemical Beach Cleaner; Proceedings of the 1991 Oil Spill Conference; API; Washington, D.C.; 1991. Fiocco, RJ. and Lessard, R.R.; Demulsifying Dispersant for an Extended Window of Use; Proceedings of the 1997 International Oil Spill Conference; API; Washington, D.C.; 1997. Fräser, J.P.; Methods for Making Dispersant Use Decisions; Proceedings of the 1989 Oil Spill Conference; API; Washington, D.C.; 1989. Harrison, O.R.; An Overview of the Exxon Valdez Oil Spill; Proceedings of the 1991 International Oil Spill Conference; API Publication 4529; Washington, DC; 1991; pp 313-319. International Maritime Organization; IMOIUNEP Guidelines on Oil Spill Dispersant Applications Including Environmental Considerations; IMO; London; 1995. Jahns, H.O.; Bragg, J.R.; and Dash, L.C.; Natural Cleaning of Shorelines Following the Exxon Valdez Spill; Proceedings of the 1991 International Oil Spill Conference; API Publication 4529; Washington, DC; 1991. Lee, K.; Lunel, T.; Wood, P.; Swannell, R. and StoffynEgli, P.; Shoreline Cleanup by Acceleration of Clay-Oil Flocculation Processes; Proceedings of the 1997 International Oil Spill Conference; API; Washington, D.C.; 1997. Lessard, R.R. and DeMarco, G.; Evolution of the U.S. Dispersant Policy Since the 1960s; SpillCon 98 Dispersant Workshop; Australian Institute of Petroleum and Australian Maritime Safety Authority; Cairns, Queensland, Australia; 1998. Lessard, R.R.; DeMarco, G.; Fiocco, R.J.; Lunel, T.; and Lewis, A.; Recent Advances in Oil Spill Dispersant Technology with Emphasis on New Capability to Disperse Heavy Oil; SPE International Conference on Health, Safety, and Environment in Oil and Gas Exploration and Production; Caracas, Venezuela; 1998. Lewis, A. and Aurand, D.; Putting Dispersants to Work: Overcoming Obstacles; API Publication No. 4652A; Washington, DC; 1997. Downloaded from http://meridian.allenpress.com/iosc/article-pdf/1999/1/357/1752190/2169-3358-1999-1-357.pdf by guest on 21 December 2021 The Exxon Valdez spill was an unfortunate accident that happened to an oil company with one of the best marine safety records in the oil industry. It demonstrated that accidental oil spills can happen to anyone, and emphasized the need for constant vigilance. It was a milestone event, not just for Exxon, but for the entire U.S. oil industry. Prevention is clearly the first priority and Exxon has taken a number of specific steps to reduce the risk of oil spills and to strengthen response capabilities. New Exxon systems have since been implemented which have reduced the rate of spillage from an already impressive record. Some of these are modified tanker routes, drug and alcohol testing programs, periodic assessment of all facilities, and strengthened pilot training programs. In the United States, the total number of Exxon oil spills reaching water has dropped dramatically since 1990. During 1997, less than 1 barrel of oil was spilled from Exxon-operated vessels worldwide. This is less than one tablespoon spilled for every million gallons transported. The marine industry average is over 100 gallons per million gallons transported. The Valdez experience ultimately led to a number of advances in oil spill response technology: • Corexit 9500 is an advanced new dispersant capable of dispersing very viscous crude oil emulsions and heavy bunker oil. The product is responsible for having made responders aware that the window of opportunity for dispersant response is much wider than previously thought. • Learnings from Exxon's application of techniques for accelerating recovery of shorelines (e.g., bioremediation) have been extensively documented and shared with others. Each of these has led to international studies which have improved on the advances originated in the Valdez response. Some of these studies are continuing ten years after the spill and Exxon's R&D continues to support a number of them. • The chemical cleaner Corexit 9580 has been demonstrated a safe and effective technique for use on shorelines as well as on vegetation. Had it been used in the Alaska cleanup, it would have undoubtedly reduced the need for hot water washing. 361 362 1999 INTERNATIONAL OIL SPILL CONFERENCE 21. Sergy, G.; Guenette, C ; Owens, E.; Prince, R.and Lee, K.; In Situ Treatment of Oiled Sediment Shorelines; Proceedings of the 1999 International Oil Spill Conference; API; Washington, D.C.; 1999. 22. Teal, A.R.; Shoreline Cleanup-Reconnaissance, Evaluation, and Planning Following the Valdez Oil Spill; Proceedings of the 1991 International Oil Spill Conference; API; Washington, DC; 1991. 23. Teas, H.; Lessard, R.R.; Canevari, G.P.; Brown, C.P.; Glenn, R.; Saving Oiled Mangroves Using a New NonDispersing Shoreline Cleaner; Proceedings from the 1993 International Oil Spill Conference; API; Washington, DC; 1993. Downloaded from http://meridian.allenpress.com/iosc/article-pdf/1999/1/357/1752190/2169-3358-1999-1-357.pdf by guest on 21 December 2021 17. Lewis, A.; Crosbie, A.; Davies, L.; and Lunel, T.; Dispersion of Emulsified Oil at Sea; Report AEAT 3475; AEA Technology pic; Oxfordshire, U.K.; 1998. 18. Michel, J. and Benggio; Testing and Use of Shoreline Cleaning Agents during the Morris J. Berman Oil Spill; Proceedings of the 1995 International Oil Spill Conference; API; Washington, D.C.; 1995. 19. National Research Council; Using Oil Spill Dispersants on the Sea; National Academy Press; Washington, D.C.; 1989. 20. Pezeshki, S.R.; DeLaune, R.D.; Nyman, J.A.; Lessard, R.R.; Canevari, G.P; Removing Oil and Saving Oiled Marsh Grass Using a Shoreline Cleaner, Proceedings of the 1995 International Oil Spill Conference; API Publication 4620; Washington, DC; 1995.