Category Archives: Environment

New EPA data: Dispersant likely not increasing acute lethality of oil in BP oil disaster

Richard Denison, Ph.D., is a Senior Scientist.

I had reported in an earlier post – based on data provided to EPA by Nalco, the maker of Corexit® 9500, the main dispersant being used in the Gulf – that the dispersant appeared to increase the acute aquatic toxicity of oil.

At a press conference today, EPA released data from the second round of its own testing on Corexit 9500 (and seven other dispersants), and concluded that the acute toxicity of the dispersant-oil mixture is about the same as the oil by itself.

What explains the discrepancy?  To put it most simply:   It's not that the dispersant-oil mixture was less toxic in the EPA tests, it's that the oil EPA used – which is the actual oil that has been leaking into the Gulf – was more toxic than the fuel oil Nalco had used.  Here's a cartoon illustrating what I'm saying (the arrow shows the biggest change):

So the good news is that the dispersant doesn't appear to be increasing the acute aquatic toxicity of the oil released into the Gulf.  The bad news is that the oil is pretty toxic, and the dispersant certainly doesn't help directly with that.  And of course, the bigger questions about longer-term effects of dispersants and dispersed oil are not addressed by the new data.   Read More »

Also posted in Health Science| Tagged , | 4 Responses, comments now closed

Exceptions swallow the rule: "Rare cases" turn into daily approvals for dispersant use

Richard Denison, Ph.D., is a Senior Scientist.

What the EPA hath sought to take away from BP, the US Coast Guard hath given back.

Remember the May 26 Directive that, well, directed BP to "eliminate the surface application of dispersants" except in "rare cases when there may have to be an exemption" and where BP submits a written request and receives an exemption in writing from the Federal On-Scene Coordinator (FOSC, currently Admiral James Watson of the Coast Guard)?

Naturally, I was curious about the nature and number of such exemptions, given that, as I noted earlier, surface application of dispersants has continued since the May 26 Directive.  After I (and others, I expect) made inquiries a couple of weeks ago to get copies of the written requests from BP and written approvals from the FOSC, the Coast Guard has informed me that it has posted these documents on the Deepwater Horizon response website.

These documents reveal that, as of June 30 (the last day for which a document has been posted as of this writing), more than 40 exemption requests have been submitted – and approved.  These exemptions have allowed surface application of dispersant to occur virtually every day since the Directive was issued.

The documents also hold some other interesting details as to the rationales offered for the exemptions and the nature of the approvals.  Read More »

Also posted in Health Policy, Health Science, Regulation| Tagged , | 3 Responses, comments now closed

Not so fast: Why dispersants EPA ranks as "practically non-toxic" are still a concern

Richard Denison, Ph.D., is a Senior Scientist.

To judge by the headlines and leads of stories that ran on the websites of the New York Times (“The E.P.A. on Dispersants: Cure Is Not Worse Than the Disease”) and the Washington Post (“Oil dispersant does not pose environmental threat, early EPA findings suggest”) reporting on an EPA conference call held Wednesday, you’d think the first round of test results on dispersants conducted by EPA answered all outstanding questions and gave their use a clean bill of health.

Hardly.  (Despite the misleading headlines and leads, the rest of these stories were more nuanced and more accurate.)

As I reported in a post Wednesday, the new acute toxicity data were from tests conducted on the dispersants by themselves, rather than mixed with oil – which is what the environment sees.  Moreover, the new data did little more than confirm already available data showing that currently listed dispersants exhibit relatively low acute toxicity to fish and shrimp, and that by themselves they are less toxic than oil by itself.

So despite the hoopla, the new data from this first round of testing are of very limited utility in answering any of the more profound questions surrounding the use of dispersants.  Read More »

Also posted in Health Science| Tagged , , | 2 Responses, comments now closed

Hurry up and wait: Not much new revealed by EPA's initial round of dispersant toxicity testing

Richard Denison, Ph.D., is a Senior Scientist.

EPA held a press call today to discuss the initial results of its own testing of oil spill dispersants.  The testing by EPA was initiated after BP resisted complying with an EPA-Coast Guard Directive issued May 20 that directed the company to identify and switch to dispersants that are less toxic and more effective than the two Corexit® dispersants on which BP has exclusively relied to mitigate the effects of the oil disaster unfolding at Deepwater Horizon.  In expressing disappointment with BP’s response to the Directive, EPA indicated it would initiate its own toxicity and effectiveness testing of Corexit and other dispersants.  Today’s call reported on round 1 of that testing.

First let me say I applaud EPA for taking on the unglamorous task of conducting further testing and seeking to answer questions that would have been nice to have had answers to well before this mess developed.  Second, I understand that testing takes time, that this is only round one and EPA says more is coming, so that at least partially compensates for the distinctly anticlimactic feeling I had listening in on today’s call.

So, what did we learn today?  Not too much new. Read More »

Also posted in Health Science| Tagged , , | 2 Responses, comments now closed

Does dispersant toxicity count? No toxicity standard limits EPA's listing of oil spill dispersants

Richard Denison, Ph.D., is a Senior Scientist.  EDF’s Health Program Intern Shannon O’Shea provided valuable assistance in the research for this post.

The more I have looked into the question of how dispersants get listed and selected under the country’s National Oil and Hazardous Substances Pollution Contingency Plan (NCP), the more disturbing it gets.

It turns out EPA regulations impose no maximum toxicity limits on dispersants allowed to be listed on the NCP Product Schedule.  Nor is such a listing deemed by EPA to be an approval or authorization for use of a dispersant on a spill – it merely signifies (with one exception) that required data have been submitted to EPA.  Yet, once listed, a dispersant is effectively “pre-authorized” for use, and the guidance provided to officials charged with deciding whether to allow use of a dispersant, and if so which one and in what quantities and settings, makes scant mention of toxicity as a factor to be considered in the selection decision.

No wonder there’s little incentive to do the research needed to understand the full scope of impacts associated with dispersant use, let alone to develop and shift to safer and more effective dispersants.

This post examines the following questions:

  • How does a dispersant get listed on the NCP Product Schedule?
  • Is listing of a dispersant considered approval for use on a spill?
  • How is a dispersant approved for use in a spill?
  • How are decisions made about dispersant use?
  • How is toxicity information considered in making decisions about dispersant use?

Read More »

Also posted in EPA, Health Policy| Tagged , , | 4 Responses, comments now closed

Is BP complying with the Directive to reduce dispersant use in the Gulf?

Richard Denison, Ph.D., is a Senior Scientist.

[Note added 6/22:  I have corrected one of the figures below, which was based on a misunderstanding of the EPA/Coast Guard Directive.  Please see this correction for the updated information and a statement from EPA.]

As of yesterday, BP’s use of dispersants to address the ongoing Deepwater Horizon spill has topped 1.4 million gallons.

On May 26, 2010, EPA and the Coast Guard issued a Directive to BP calling for significant reductions in BP’s use of dispersants.  That directive set out three requirements:

  • Eliminate surface application of dispersant except in rare cases where exemptions are requested in writing and granted by the Coast Guard’s Federal On-Scene Coordinator (FOSC).
  • Limit subsurface application of dispersant to a maximum of 15,000 gallons per day.
  • Overall goal of reducing dispersant use by 75%.

Has BP complied?  The short answer is not even close.  The details follow.  Read More »

Also posted in Health Policy| Tagged , | 2 Responses, comments now closed

EPA data show dispersants plus oil are more toxic than either alone

Richard Denison, Ph.D., is a Senior Scientist.

In an earlier post, I noted in haste some apparent discrepancies between EPA and BP acute toxicity data on the Corexit® dispersants.  Little did I realize that the data mixup was actually telling me something much more significant:  that the dispersant maker’s own test data demonstrate that the combination of oil plus dispersant is quite a bit more toxic than the dispersant alone and – even more significant – the combination is more acutely toxic than the oil by itself.

Let me repeat that:  The data indicate that dispersed oil is more toxic than undispersed oil.  Read More »

Also posted in Health Science| Tagged , , | 8 Responses, comments now closed

Another BP leak – this time, it's their 2009 Gulf of Mexico oil spill contingency plan

Richard Denison, Ph.D., is a Senior Scientist.

Just as BP seems to be making some progress in slowing the leakage of oil from Deepwater Horizon, another leak has appeared.  Karen Dalton Beninato, writing on, has obtained, and posted for all to see, a copy of BP’s June 2009 “Gulf of Mexico Regional Oil Spill Response Plan” (caution, it’s a 600-page, 29 MB PDF file!).  [Note added 6/8:  Not sure how long it's been posted, but the BP Plan is up on the Minerals Management Service website, under "Documents" here (double caution:  this version is a 61 MB PDF!)]

There are some embarrassing parts, with no doubt more waiting to be discovered.  Here’s one example:  The Plan’s “worst-case scenario” for sites more than 10 miles offshore is a total leakage of 177,400 barrels of crude oil (Appendix H).  As reported by the Washington Post this morning, government estimates put the size of this spill at between 23 and 47 million gallons, or between 548,000 and 1.12 million barrels, and counting.

On the issue of dispersants, the Plan is also revealing.  Read More »

Also posted in Health Science| Tagged , , , | 4 Responses, comments now closed

Just what the doctor ordered: EPA tells BP to use less toxic oil dispersants in the Gulf

Richard Denison, Ph.D., is a Senior Scientist.

This just out:  The Washington Post is reporting that EPA has given BP 24 hours to identify and locate a supply of a less toxic dispersant to be applied to the Gulf oil spill, and to begin using it within an additional 72 hours.

As noted in my last post, EPA has identified numerous alternative dispersants that are both less toxic and more effective than those on which BP has been relying to date — more than 600,000 gallons of which have already been released into Gulf waters.  The Post also notes that some forms of the initial dispersants, sold by Nalco under the trade name Corexit®, were banned by the British government more than a decade ago.

Also posted in Health Science| Tagged , , | Comments closed

Compounding the problem: Why aren’t we using the safest and most effective dispersants in the Gulf?

Richard Denison, Ph.D., is a Senior Scientist.

Imagine learning you have a serious disease.  Your doctor decides to treat you with a drug, noting it could have some bad side effects.  He also plans to inject you with the drug, even though it’s only been used orally before now.  That makes you nervous enough to ask for the name of the drug. “Sorry, I can’t tell you,” he says.  “It’s proprietary.”  Even if you trust your doctor, you’re now left with no way to investigate the risks and tradeoffs you’re facing.

Imagine how mad you’d be if you learned your doctor hadn’t told you there were other drugs that not only had fewer side effects, but were more effective in treating your condition.  And then you learn he’s on the Board of Directors of the company that makes the drug he prescribed.

Now consider that the patient is the Gulf of Mexico, the doctor is BP, and the drug is the oil dispersants, sold by Nalco under the trade name Corexit®, more than 500,000 gallons of which have been applied to date, with no end in sight.  Read More »

Also posted in Health Policy, Regulation, TSCA Reform| Tagged , , , , , | 8 Responses, comments now closed
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