This report examines the use of chemical dispersants in the aftermath of the 2010 Deepwater Horizon oil spill.

This book examines the issues raised by the use of dispersants in the Deepwater Horizon spill. Dispersants change the distribution, not the amount, of oil within a marine environment. They are chemicals typically applied directly to oil on the water surface in order to break the oil into small droplets that can then mix with water below the surface. Discussed in this compilation is how well the government handled the dispersant issues it faced in the absence of necessary scientific information and pursuant to a regulatory regime that had failed to anticipate this kind of problem, and in light of lessons learned from this experience, how government procedures and existing laws might be improved to allow for sounder decisions regarding the use of dispersants in the future.

"The purpose of this report is to provide the Federal On-Scene Coordinator for the Deepwater Horizon MC252 Spill of National Significance with sufficient information to determine the presense or absence of sub-surface oil and dispersants amenable to removal actions under the provisions of the Clean Water Act, the Oil Pollution Act of 1990, and the National Oil and Hazardous Substances Pollution Contingency Plan."--Executive summary.

Whether the result of an oil well blowout, vessel collision or grounding, leaking pipeline, or other incident at sea, each marine oil spill will present unique circumstances and challenges. The oil type and properties, location, time of year, duration of spill, water depth, environmental conditions, affected biomes, potential human community impact, and available resources may vary significantly. Also, each spill may be governed by policy guidelines, such as those set forth in the National Response Plan, Regional Response Plans, or Area Contingency Plans. To respond effectively to the specific conditions presented during an oil spill, spill responders have used a variety of response optionsâ€"including mechanical recovery of oil using skimmers and booms, in situ burning of oil, monitored natural attenuation of oil, and dispersion of oil by chemical dispersants. Because each response method has advantages and disadvantages, it is important to understand specific scenarios where a net benefit may be achieved by using a particular tool or combination of tools. This report builds on two previous National Research Council reports on dispersant use to provide a current understanding of the state of science and to inform future marine oil spill response operations. The response to the 2010 Deepwater Horizon spill included an unprecedented use of dispersants via both surface application and subsea injection. The magnitude of the spill stimulated interest and funding for research on oil spill response, and dispersant use in particular. This study assesses the effects and efficacy of dispersants as an oil spill response tool and evaluates trade-offs associated with dispersant use.

Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 195. Monitoring and Modeling the Deepwater Horizon Oil Spill: A Record-Breaking Enterprise presents an overview of some of the significant work that was conducted in immediate response to the oil spill in the Gulf of Mexico in 2010. It includes studies of in situ and remotely sensed observations and laboratory and numerical model studies on the four-dimensional oceanographic conditions in the gulf and their influence on the distribution and fate of the discharged oil. Highlights of the book include discussions of the following: immediate responses to the Deepwater Horizon oil spill using Integrated Ocean Observing System resources; monitoring the surface and subsurface oil using satellites, aircraft, vessels, and AUVs; mapping the oceanographic conditions using satellites, aircraft, vessels, drifters, and moorings; modeling the spreading of surface oil trajectories and the three-dimensional dispersal of subsurface hydrocarbon plumes; oil spill risk analyses and statistical studies on the fate of the oil; and laboratory investigation of ocean stratification related to subsurface plumes. This book will be of value to scientists interested in the Deepwater Horizon oil spill, the Gulf of Mexico, and the potential for conveyance of oil spilled in the Gulf of Mexico to the North Atlantic. A more technical audience may include those interested in oil spill detection, trajectory model forecasting, and risk analyses and those with an interest in applied oceanography, including scientists, engineers, environmentalists, natural and living marine resource managers and students within academic institutions, agencies, and industries who are involved with the Gulf of Mexico and other regions with offshore oil and gas exploration and production.

Oil spills can be difficult to manage, with reporting frequently delayed. Too often, by the time responders arrive at the scene, the slick has moved, dissolved, dispersed or sunk. This Oil Spill Monitoring Handbook provides practical advice on what information is likely required following the accidental release of oil or other petroleum-based products into the marine environment. The book focuses on response phase monitoring for maritime spills, otherwise known as Type I or operational monitoring. Response phase monitoring tries to address the questions – what? where? when? how? how much? – that assist responders to find, track, predict and clean up spills, and to assess their efforts. Oil spills often occur in remote, sensitive and logistically difficult locations, often in adverse weather, and the oil can change character and location over time. An effective response requires robust information provided by monitoring, observation, sampling and science. The Oil Spill Monitoring Handbook completely updates the Australian Maritime Safety Authority’s 2003 edition of the same name, taking into account the latest scientific advances in physical, chemical and biological monitoring, many of which have evolved as a consequence of major oil spill disasters in the last decade. It includes sections on the chemical properties of oil, the toxicological impacts of oil exposure, and the impacts of oil exposure on different marine habitats with relevance to Australia and elsewhere. An overview is provided on how monitoring integrates with the oil spill response process, the response organisation, the use of decision-support tools such as net environmental benefit analysis, and some of the most commonly used response technologies. Throughout the text, examples are given of lessons learned from previous oil spill incidents and responses, both local and international. General guidance of spill monitoring approaches and technologies is augmented with in-depth discussion on both response phase and post-response phase monitoring design and delivery. Finally, a set of appendices delivers detailed standard operating procedures for practical observation, sample and data collection. The Oil Spill Monitoring Handbook is essential reading for scientists within the oil industry and environmental and government agencies; individuals with responder roles in industry and government; environmental and ecological monitoring agencies and consultants; and members of the maritime sector in Australia and abroad, including officers in ports, shipping and terminals.