USE OF DISPERSANTS - U.S. National Response Team (NRT)

areas may not be feasible. For these reasons, dispersant application is an important complementary spill responsetechnique and should be included along with other techniques as on option in developing the appropriate responsestrategy. Under the Letters of Agreement, use of dispersants will be considered when and where physical removal isimpossible or insufficient for protecting natural resources, including listed species.In-Situ BurningIn-situ burning is an oil spill response technique that can quickly remove large volumes of oil from the water surfaceby igniting oil that is towed away from the main slick in fire-resistant boom. Though in-situ burning is a highlyuseful and important response option, there are some differences in the range of oil and weather conditions underwhich in-situ burning and dispersants are effective. For example, in-situ burning is not effective once oil has spreadto less than about two millimeters thick. Also, if winds are blowing shoreward toward populated areas or sensitiveenvironments, in-situ burning is unlikely to be employed due to concerns about potential effects of the smoke plume.Under conditions for which in-situ burning would not be effective or creation of a smoke plume is deemedunacceptable, dispersants may be a viable option.No ActionAnother alternative is not attempting to remove released oil from the water surface, potentially allowing the oil towash ashore. The oiled shoreline could be cleaned or allowed to recover naturally. Due to the importance ofnearshore and shoreline habitat to a variety of organisms and the difficulty of cleaning oiled shorelines withoutinflicting further injury, this alternative is considered the least desirable from several perspectives, includingprotection of listed species and critical habitat. Unrecovered oil poses a high risk of exposure and injury to wildlife,especially sea birds, marine mammals, and intertidal organisms. Cleaning and rehabilitation of oiled wildlife,particularly marine mammals, have had limited success and release of rehabilitated animals creates a risk ofintroducing disease into wild populations.ConclusionsThe purpose of dispersants, used alone or in conjunction with other open-water spill response techniques, is toquickly remove spilled oil from the water surface, thereby reducing exposure to wildlife and preventingcontamination of sensitive nearshore and shoreline habitat. Under appropriate conditions, dispersants can reduceenvironmental impacts from oil spills, including injury to listed species and critical habitat. Dispersant application isnot likely to adversely affect listed species beyond the potential effects of the spilled oil or add to the cumulativeenvironmental stresses currently acting on the species.The parties to these Caribbean Letters of Agreement pre-authorizing dispersants as an oil spill response technique inthe designated zones conclude that this action is not likely to adversely affect the listed species or critical habitatpresent in the area under consideration and that formal consultation under Section 7 of the Endangered Species Actis not necessary. We request that you concur with these conclusions. Consultation will be re-initiated if additionalinformation not previously considered becomes available indicating adverse effects to listed species or criticalhabitat from the identified action.ReferencesAllen, A. A. and R.J. Ferek. 1993. Advantages and disadvantages of burning spilled oil. In Proceedings of the1993 International Oil Spill Conference, March 29 - April 1, 1993, Tampa, Florida, pp. 765-772.Ernst, C.H., J. Lovich, and R.W. Barbour. 1994. Turtles of the United States and Canada. Washington D.C.:Smithsonian Institution Press, pp. 29-102.Fritts, T.H. and M.A. McGehee. 1982. Effects of Petroleum on Development and Survival of Marine TurtleEmbryos. USFWS/OBS-82/37. USDOI, Fish and Wildlife Service, 41 pp.Geraci, J.R. 1990. Physiologic and toxic effects on cetaceans. In Sea Mammals and Oil: Confronting the Risks.