After speaking with the Joint Incident Command group this weekend, here’s an overview of what I’ve found out about dispersants used in the Gulf to control, contain and cleanup the BP oil spill...

- Dispersants are chemicals that can be used to break up oil and speed its natural degradation. They are generally less harmful than oil and biodegrade more quickly than untreated oil.

- According to EPA, dispersants have been useful in breaking up the oil offshore and preventing more oil from reaching fragile coasts and wetlands.

- BP has been allowed to use dispersants during this disaster because the spill was more than three miles from the shoreline. For this use, BP has been preauthorized to use approved dispersants. Conversely, BP has had to get daily approval from the Coast Guard and EPA to use dispersants in any surface applications.

*Each of these approvals and requests can be found at http://www.deepwaterhorizonresponse.com

- The EPA has been testing for dispersants near the shore and has detected no dispersant compounds. National Oceanic and Atmospheric Administration (NOAA) and EPA scientists are conducting rigorous ongoing monitoring and analysis of the effectiveness and toxicity of the dispersants used.

*As of the date of the EPA’s document, toxicity testing had not shown any significant effects of dispersants on aquatic life.

 - Mobile air monitors (see photo) taking samples throughout the region have detected only very small amounts of compounds that may be related to dispersants.

*I came upon one of these monitoring units on the sand dunes at Orange Beach just yesterday. The cleanup crew member I talked to had no idea what the device was or who had placed it on the sand dune.

 - While there has been concern that a lot of dispersant has been used because of the scope of the oil spill, the Coast Guard is tasked with approving surface dispersant application when preferred control methods such as skimming or burning are not available due to weather conditions or oil location.

*BP had a daily limit of 15,000 gallons back when the well was leaking oil.

- EPA began its own scientific testing of eight dispersant products and subsequently found that none of the eight dispersants tested, including the product in use in the Gulf, displayed biologically significant endocrine disrupting activity.*While most of the dispersant products alone have roughly the same impact on aquatic life, JD-2000 and Corexit 9500 were generally less toxic to small fish and JD-2000 and SAF-RON GOLD were least toxic to mysid shrimp.

 - Additional testing is needed to determine the acute toxicity of multiple concentrations of Louisiana Sweet Crude Oil alone and of combinations of Louisiana Sweet Crude Oil with each of the eight dispersants for two test species.

 - The EPA publishes a more detailed form on dispersants at its Website. For more information, visit http://www.epa.gov/bpspill/dispersants.

 - From that data referenced in #9, the chemical components of the dispersants COREXIT 9500 and COREXIT 9527 are...(Each is listed with CAS Registry Number and then  the Chemical Name)

57-55-61,2-Propanediol
111-76-2 Ethanol, 2-butoxy-*
577-11-7 Butanedioic acid, 2-sulfo-, 1,4-bis(2-ethylhexyl) ester, sodium salt (1:1)
1338-43-8 Sorbitan, mono-(9Z)-9-octadecenoate
9005-65-6 Sorbitan, mono-(9Z)-9-octadecenoate, poly(oxy-1,2-ethanediyl) derivs.
9005-70-3 Sorbitan, tri-(9Z)-9-octadecenoate, poly(oxy-1,2-ethanediyl) derivs
29911-28-2 2-Propanol, 1-(2-butoxy-1-methylethoxy)-
64742-47-8 Distillates (petroleum), hydrotreated light

*Note: This chemical component (Ethanol, 2-butoxy-) is not included in the composition of COREXIT 9500.

Ultimately, I’ve only been able to gather information on the dispersants through forms and communication with the Joint Incident Command.

I’ll have more insight when I interview LuAnn White at Tulane University tomorrow.