Nick Snow
OGJ Washington Editor
WASHINGTON, DC, Aug. 2 -- The dispersant used in response to the BP PLC crude oil spill in the Gulf of Mexico is generally no more or less toxic when mixed with oil than other oil-dispersant mixtures, the US Environmental Protection Agency said. Results of its test of dispersant and oil mixtures indicate that they were generally no more toxic than crude alone, it added.
“EPA has committed to following the science at every stage of this response; that’s why we required BP to launch a rigorous dispersant monitoring program, why we directed BP to analyze potential alternatives, and why EPA undertook this independent analysis of dispersant products,” said Lisa P. Jackson, the agency’s administrator.
“We have said all along that the use of dispersant presents environmental tradeoffs, which is why we took steps to ensure other response efforts were prioritized above dispersant use and to dramatically cut dispersant use,” she continued as EPA released the test’s results on Aug. 2. “Dispersant use virtually ended when the cap was placed on the well, and its use dropped 72% from peak volumes following the joint EPA-US Coast Guard directive to BP in late May.”
The findings were released 2 days before the US Senate’s Environment and Public Works Committee was scheduled to hold a hearing on the use of dispersants after oil began to leak from BP PLC’s Macondo well in the gulf after it blew out on Apr. 20. The explosion of Transocean Ltd.’s Deepwater Horizon semisubmersible rig killed 11 workers, and the rig’s collapse into the water ruptured connecting lines immediately beneath, setting off a massive spill.
A provision of HR 3534, which the House passed by 16 votes on July 30, also dealt with dispersants and their use in combating offshore oil leaks and spills.
EPA said it tested Corexit 9500 A, which BP used to battle the spill, as well as Dispersit SPC 1000, Nokomis 3-F4, Nokomis 3-AA, ZI-400, SAFRON Gold, Sea Brat No. 4, and JD 2000 in mixtures with Louisiana sweet crude oil during this second toxicity testing round on juvenile shrimp and small fish found in the gulf. The same eight dispersants were tested in the first round.
It found all eight dispersants were less toxic than the dispersant-oil mixture to the test species, that Louisiana sweet crude was more toxic to mysid shrimp than each dispersant alone, and that oil by itself had similar toxicity to mysid shrimp as the dispersant-oil mixtures with the exception of Nokomis 3-AA, which was found to be more toxic than oil.
EPA ordered BP to analyze potential alternatives to Corexit 9500 A for toxicity and effectiveness before it directed the damaged well’s operator to reduce its use of dispersants. When BP reported it could not find an alternative less toxic than Corexit, EPA began its own scientific tests of the eight dispersant products, it said.
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US Government Accountability Office.
