After a deluge of questions on FB to the EA about dispersants they sent out this about them:

[The Straight Story]

Questions and Answers on Dispersants

* Dispersant Application
* Monitoring and assessment of dispersants used in the BP spill response
* EPA’s list of authorized dispersants (NCP Product Schedule)
* Dispersant effects
* Surface use of dispersants
* Underwater use of dispersants
* General information about dispersants

Dispersant Application

* What is the current situation with subsea and surface dispersant use in relation to the BP Oil Spill?
* Given reports of dispersant toxicity, why would you even allow any application to continue?
* One step in the Lower Marine Riser Package (LMRP) Cap tactic is cutting the riser attached to the Blowout Preventer (BOP). Once BP cuts the riser, there could be an increased flow. Are you going to allow BP to increase their usage of dispersant then?

Monitoring and Assessment of Dispersants Used in the BP Spill Response

* What directives have been issued to BP with respect to its use of dispersants?
* Has BP been complying with EPA’s request to identify a less toxic dispersant alternative?
* What monitoring is BP required to perform regarding the subsea application of dispersants?
* What is dissolved oxygen (DO) and why would dispersant application monitoring be stopped if DO levels dropped?
* The monitoring and assessment directive calls for the use of a "CTD rosette." What is a CTD rosette?
* What is a toxicity test?
* What types of toxicity tests are required to monitor the biological impacts of subsurface dispersant application?
* There is toxicity test data available for the dispersants on the NCP Product Schedule and it talks about LC50s. What is an LC50?
* To date, how much dispersant has been used in the BP Oil Spill response? Is BP is running out of dispersants?
* How do scientists identify if the oil is dispersed?
* Why do scientists measure oil droplet size?
* How do scientists measure oil droplet size?

EPA’s List of Authorized Dispersants (NCP Product Schedule)

* BP is using Corexit 9500A dispersant. What can you tell us about about the ingredients or chemical composition of this product?
* Does EPA make a determination on the toxicity of dispersants before they are approved?
* EPA lists all dispersants that have been authorized for use on National Contingency Plan (NCP) Product Schedule

Dispersant Effects

* What are the tradeoff considerations being weighed regarding the impact of fish and wildlife when making decisions about the subsea use of dispersants?
* Are any human health effects expected as a result of using the dispersants?
* What effects could the use of dispersants have on marine life?
* How will we know the future and total effects on marine life of dispersant use?
* Apart from marine life, has the Unified Command been able to make an assessment on the effects of the dispersant on the environment?
* How will the government ensure the protection of the environment when dispersants are used?

Surface Use of Dispersants

* How do dispersants work on the water’s surface?
* Surface Use of Dispersants in the Response to the BP Spill

Underwater Use of Dispersants

* How do dispersants work under the water?
* Underwater Use of Dispersants in the Response to the BP Spill
* Is the underwater chemical dispersant that EPA approved contributing to underwater oil plumes?

General Information about Dispersants

* Have dispersants ever been used this much before?
* What are the future plans for use of dispersants for oil spills? Will the industry and federal government look to continue their use?
* Some History of Dispersant Use

Answers here:
http://www.epa.gov/bpspill/dispersants.html#qanda2