[Update 5/20/10 2:07 MDT: EPA issued a directive requiring BP to use a less toxic and more effective dispersant from the list of EPA authorized dispersants.]

On Monday I was invited to participate in a conference call with Rear Admiral Mary Landry, Federal On-Scene Coordinator for Unified Area Command, Deepwater Horizon Response. I asked Adm. Landry about the unprecedented use of subsea dispersants and what the ongoing testing and monitoring protocol looks like now that BP has resumed use of the dispersants near the wellhead, almost one mile below the surface of the ocean. In stead of parsing Adm. Landry's thoughtful response, I've reprinted it in its entirety.

Tim Hurst: Admiral, my question -- now that BP has resumed the use of subsea dispersants, I was hoping you could elaborate or comment on what if anything is being done in the ongoing process as these are being deployed at much deeper depths or, you know, unprecedented depths in unprecedented volumes.

ADM. LANDRY: I can. And thanks for your question. And I know -- if you didn't have the benefit of hearing or getting our quotes from any of the press conferences we've had, I really explained very carefully, as we march down the road to consideration for subsea dispersant, technically, we had pre-approval for dispersant in the Gulf of Mexico. And this pre-approval was granted, and it's built into the response plan.

After, you know, several years of analysis and peer review and science looking at it, it's certainly a trade-off.

When you decide to use dispersants even on the surface, you're basically saying that, you know, we already have the spill, we've got to minimize environmental impact as much as possible. And the value of dispersants off shore outweighs the benefit or the impact that could be felt near shore with the marshes and other areas.

That being said, I have a great respect for those who are concerned about the whole ecology of the Gulf of Mexico. So when we started using dispersants on the surface, it was really clearly with the guidance and protocols that are established in this pre-approval agreement. And we stuck very strictly to the protocols that are outlined.

We also started thinking about subsea injection, because, as you know, never been tried before in those depths, BP was proposing it. We were looking at it to say, you know, could you have less impact? And obviously, you use less volume. But could you have less impact, less negative impact overall? And so it was through the efforts of both the regional response team and the national response team.

I technically could have signed off on it right here. EPA and I could have signed off on it through the RRT right here and just moved ahead. But when that pre-approval was given for the surface dispersant, the pre-approval never envisioned subsea injection. And that's why we moved so cautiously to cross that threshold and consider it.And we only did it after a series of three different tests. The first test took place, and then folks came back and looked at the results and said, you know, I want a little more testing in a few other areas. So they added some other sampling criteria. And we required through the second test that sampling criteria.

And then they examined and said, you know, let's do a third test just to make sure we're not overlooking anything. And they were doing this in dialogue, in concert with the head of the EPA, Lisa Jackson, the head of NOAA, Dr. Lubchenco, and the career people that work for all those folks, who were heavily engaged in hard work and dialogue as we began to consider using this.

And they even engaged scientists as they crossed the threshold before they made the announcement to go ahead and use it. We are doing a very strict monitoring protocol right now. As we do this injection of subsea dispersant, there are sample being taken through the water column on the surface. You know, they're using all the technologies that are necessary to examine the impact that this is going to have. And they're not going to just stop with the sampling and analysis while we're injecting subsea dispersant. It's understood there will be long-term studies, near-term and long-term studies about this.

So it's a threshold we crossed. The decision was made based on extensive evaluation of the pros and cons. But I can tell you that I know the administrator of the EPA and the head of NOAA both want to engage the scientific community as we examine and analyze what the impacts are. And that's what will be done and what is promised to everyone.

Tim Hurst: Okay, thank you.

LT. CRAGG: Thank you, ma'am. And thank you, Tim.