Dispersants are chemical agents (similar to soaps and detergents) that help break up an oil slick into very small droplets, which dilute throughout the water. While this does not remove the spilled material, smaller oil particles are more easily biodegraded and it provides a measure of protection for sensitive habitats threatened by a surface slick. Dispersants are sprayed onto spills by specially equipped boats or planes.
All environments contain naturally occurring microbes that feed on and break down crude oil. Dispersants aid biodegradation by forming tiny oil droplets, typically less the size of a period on this page (<100 microns), making them more available for microbial degradation. Wind, current, wave action, or other forms of turbulence helps this process. The increased surface area of these very small oil droplets makes the oil much easier for the petroleum-degrading microorganisms to consume.
Dispersants are one of several tools available to combat oil spills and are a necessary component of an effective response to large volume offshore spills when used appropriately. Its application, both surface and subsurface, is a critical element in preventing significant oiling of sensitive shoreline habitats during an oil spill response. However, misperceptions and knowledge gaps led to unanticipated restrictions on dispersant use during the Deepwater Horizon incident.
The Oil Spill JITF identified several recommendations to provide better understanding on the appropriate use of dispersants during an oil spill response and to improve on best practices in dispersant use, technology and application.
Improving Dispersant Communication Tools
Better communication is needed to promote understanding of the benefits and limitations of dispersants during a response effort, as well as the safety and effectiveness of dispersant products. The JITF is developing a series of fact sheets and other communication tools to address various aspects of dispersants. These tools will assist industry and government officials in educating the public and community stakeholders about what dispersants are, how they work, when their use is considered, and any associated environmental trade-offs and potential human health effects.
In addition, regional workshop are being conducted to facilitate communication with local stakeholders (e.g., non-government organizations (NGOs), elected officials, fishermen, academics, journalists, health leaders, etc.) about dispersant use for oil spill response in a specific sensitive, coastal environments. These stakeholders typically operate outside of traditional spill preparedness activities, and there is generally little interaction with ACs and Regional Response Teams (RRTs), because their missions are different than those associated with an oil spill response. It is expected that these workshops may serve as a model for increasing engagement with stakeholders in other areas and could serve to enhance future oil spill preparedness and response.
Assessing Research Efforts and Needs
Since the Deepwater Horizon oil spill, a number of dispersant-related research meetings have occurred or are planned. Because of this, the JITF recognized the need to interact at some level with all of these efforts and is developing a means to enhance coordination of research efforts overall. All of these efforts are seen as opportunities to solidify a working relationship with Federal government, Industry, and academia that will be involved in Gulf of Mexico (GOM) oil spill-related research in the foreseeable future.
In addition to direct interaction of researchers and the resultant exchange of ideas, there is a need to review, evaluate, and possibly address published research results in a timely manner. Toward this end, an expert panel will be chartered to review data collection efforts for spill impact assessments and evaluation of ecological recovery rates for offshore, near-shore, coastal and estuarine areas impacted by spills.
Subsea Injection of Dispersants
Subsea dispersant injection is a novel technique that was used during the Deepwater Horizon oil spill response effort. This technique played an important role in not only protecting the environment but also the health and safety of workers in vessels attempting to contain the well. Industry plans to incorporate this tool in response strategies for deepwater wells.
To support its use, API and its industry companies have developed a large-scale, multiple-year Subsea Dispersant Program to conduct controlled experiments. The Program will study the effectiveness of subsea injection over a range of conditions, the effects of dispersed oil on deepwater marine environments, numerical modeling upgrade needs that are necessary to better predict the fate of oil treated with dispersant and released from a deepwater well, and monitoring tools that could be used to determine the effectiveness of subsea injection during an event.
Review of Surface Application Techniques
Lessons learned from operational teams of the Deepwater Horizon response incident regarding targeting and application capabilities suggest that there were many complications to dispersant use that surrounded application. A project team formed to review dispersant surface application techniques and processes in order to validate safety margins and promote the use of as little dispersant as necessary to disperse the oil. When complete, the document will contain a prioritized list of areas of improvements on this issue. These items, along with the document as a whole, will be used as the foundation for Industry-government dialogue on a path forward.