Source: Deepwater Horizon Unified Command Response
Oil spill dispersants are chemicals that attempt to break down the oil into small drops and prevent it from reaching the surface or the U.S. shoreline. Dispersants are generally less harmful than the highly toxic oil leaking from the source and biodegrade in a much shorter time span.
The use of the dispersant at the source of the leak represents a novel approach to addressing the significant environmental threat posed by the spill. Preliminary testing results indicate that subsea use of the dispersant is effective at reducing the amount of oil from reaching the surface -- and can do so with the use of less dispersant than is needed when the oil does reach the surface. This is an important step to reduce the potential for damage from oil reaching fragile wetlands and coastal areas.
“We will continue our relentless efforts to secure the source of the spill. In the meantime, we will employ every available technique we can to minimize the environmental impact on coastal habitats, communities and the marine ecosystem. This requires a responsible assessment of the risks and benefits of specific tactics,” said Coast Guard Admiral Thad W. Allen, the national incident commander for the spill.
“Based on the scientific analysis of the EPA and NOAA and review by the National Response Team, it has been determined that the use of dispersants at the subsea source is the prudent and responsible action to take along with other tactics including surface dispersant, skimming and controlled burns."
This course of action was decided upon with thorough evaluation and consideration of many factors as well as consultation with stakeholders. While BP pursues the use of subsea dispersants, the federal government will require regular analysis of its effectiveness and impact on the environment, water and air quality, and human health through a rigorous monitoring program. EPA's directive to BP, including the monitoring plan the company must adhere to in order to ensure the protection of the environment and public health.