Under a new plan from the EPA, BP must conduct constant monitoring of dispersant use at the source of a major oil leak in the Gulf of Mexico, and source and provide data to the government.

The EPA late Wednesday, May 19, 2010, began posting results from the ongoing monitoring of BP's use of underwater dispersants in the Gulf of Mexico at www.epa.gov/bpspill.

On May 15, the agency and the U.S. Coast Guard authorized BP to use dispersants underwater at the source of the Deepwater Horizon leak. As the dispersant is used underwater, BP was required to do constant, scientifically rigorous monitoring so EPA scientists may determine the dispersant's effectiveness and impact on the environment, water and air quality, and human health. The agency is posting the information BP collects during the monitoring to ensure the public has access to this data.

While the EPA said it has not yet identified any significant effects on aquatic life, the agency on Thursday, May 20, 2010, also directed BP to begin using, within 72 hours, a less toxic and more effective dispersant. The agency said it took this step because BP is using this dispersant in unprecedented volumes and, last week, began using it underwater at the source of the leak – a procedure that has never been tried before. Given the unprecedented use, the EPA said it wants to ensure BP is using the least toxic approved product.

Regardless of which dispersant BP uses, the agency said it will closely scrutinize the monitoring results, and reserves the right to stop the company's use of dispersants underwater entirely if the science indicates that this dispersant method has negative impacts on the environment that outweighs its benefits.

The public can see results of the agency's ongoing air, water and soil quality monitoring on www.epa.gov/bpspill and on the dispersants in particular at www.epa.gov/bpspill/dispersants.html.

Additional information on the broader response from the U.S. Coast Guard and other responding agencies is available at www.deepwaterhorizonresponse.com.

Update 5/24:

The agency has also published BP's response to the Directive on Dispersants (available at the dispersants link above).

BP and several of the dispersant manufacturers claimed some sections of BP's response contain confidential business information (CBI). By law, CBI cannot be immediately made public except with the company's permission. The EPA challenged these companies to make more information public and, as a result, several portions of the letter can now be made public. The agency is currently evaluating all legal options to ensure that the remaining redacted information is released to the public.

SOURCES: Agency press releases of May 20, 2010 and May 24, 2010