Mariah - The Truth About Dispersants

Thank you for viewing my presentation. Here's what I would like to know from you: What is your personal opinion on dispersant usage and water safety?

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- Mariah

Informative Speech Final Draft, March 10, 2011

1. Mariah Singerman

2. The Truth about Dispersants

3. To inform

4.  As a result of my presentation, my audience will be able to describe the effects of dispersants.    


[coverslide][pp: toxic slide] The same dispersant that was heavily used in the oil spill was deemed so toxic that the UK’s Marine Management Organization completely banned it from use in British waters. Yet more than a million gallons of dispersant was applied to surface oil, with more than 700,000 gallons put underwater in the Gulf.   If it’s not safe for British waters, why is it safe for the Gulf of Mexico? As we all know, the oil that gushed into our ocean is toxic and harmful to plants, animals, and humans. Chemical dispersants are also very toxic. [pp: lifestyle slide] Since we live along the Gulf Coast, eat the seafood, and swim in the ocean, we all need to know the truth about dispersants. As an avid beachgoer in the summertime, I want to know what the water that I’m swimming in is safe for my body and for the creatures that live in it. Today you will learn what dispersants are, their benefits, and their effects on the environment.


I. Definition

            [pp: dispersant jug] Dispersants are chemicals designed to be sprayed onto oil slicks to accelerate the process of natural dispersion. When used appropriately, dispersants can be an effective method of response to an oil spill. They are capable of rapidly removing large amounts of certain oil types from the sea surface by transferring it into the water column.

A. What it is

            Dispersants are full of chemical compounds, and have two main components: a surfactant and a solvent. Surfactants molecules are made up of two parts: an oleophilic part that is attracted to oil and a hydrophilic, a part that is attracted to water.

B. How it works

            According to Jeff Goodell, author of “The Poisoning,” Chemical dispersants work similarly to dishwashing detergent, causing oil to break up into smaller droplets and move it from the ocean’s surface down to the waters below. In theory, these smaller droplets make it easier for bacteria and other natural processes to digest the oil. Dispersants are designed to break up surface oil slicks, dilute surface oil and transfer it to the water column, and prevent tar balls from forming.

C. Dispersants in action

            [pp: dispersant diagram] When dispersants are sprayed onto an oil slick, the solvent will dissolve and distribute the surfactants through the oil slick to the surface where oil and water meet, where they arrange themselves so that the oleophilic part of the molecule is in the oil and the hydrophilic part is in the water. This causes the oil and water surface to break apart, and small oil droplets will break away from the oil slick with the help of wave movement. If dispersion is successful, a characteristic brown plume of oil will spread slowly down from the water surface.

            There were direct benefits of dispersant usage.

            II. Benefits

Dispersants were used for several reasons. While there were some logical and practical reasons to use dispersants, there were also hidden reasons that people may not know about.

[pp: practical reasons] A. Practical Reasons

            Dispersants were used in the Gulf Coast oil spill because they are fast-working, use less manual labor, and are inexpensive. It only takes a few minutes for the oil to start breaking up and sinking after the dispersant is applied. The EPA claims that dispersants are generally less harmful than the highly toxic oil leaking from the source and biodegrade in a much shorter time span. With all toxic damage aside, dispersants were the best way to break up the heavy, sludgy oil. Dispersants are also easily applied. Specially equipped aircraft and boats can spray dispersant on oil slicks quickly and efficiently.

But there were also insidious reasons for dispersant usage.

[pp: other reasons] B. Other Reasons

            Because the use of dispersants was pre-approved in BP’s response plan, there was little oversight provided by federal health or safety agencies. Despite professionals knowing much of the damage dispersants could cause, they were used heavily. BP gave a total of $25 million to Louisiana State University, the Florida Institute of Oceanography and the Northern Gulf Institute to create a base-line study for future studies on dispersant. Then former head of BP, Tony Hayward said "It is vitally important that research start immediately into the oil and dispersant's impact, and that the findings are shared fully and openly. We support the independence of these institutions and projects, and hope that the funding will have a significant positive effect on scientists' understanding of the impact of the spill.” Intense research began after the damage was done.  Chemical dispersants also helped BP by effectively covering up the spill. Once the oil was not immediately visible, people started calming down. PR stands for public relations, a field concerned with the public image of companies. In an interview for Rolling Stone, Rick Steiner, a marine scientist who helped cleanup efforts in the Exxon Valdez oil spill, says “It’s about PR. It’s about keeping the oil out of sight, and out of the public mind, so fewer people really understand what is happening and get outraged by it.” When the oil was taken off the surface of the water, it looked like no oil spill had ever happened. But all the oil was still there, just in smaller form and underwater.

While there were some benefits to dispersant usage the overall negative effects are greater.

III. Negative Effects

            Some of the chemical ingredients in dispersants are highly toxic to humans and animals. According to The International Tankers Pollution Federation Limited, One of the most difficult decisions that oil spill responders and natural resources managers face during a spill is evaluating the environmental trade-offs associated with dispersant use. One type that that was used heavily in the spill is called Corexit 9527. It contains an ingredient called 2-butoxyethanol, known to cause internal bleeding and kidney damage.  

A. Animals

            1. Tradeoffs

[pp: sea life diagram] Unfortunately, much of the specific effects of dispersant on animals are unknown, especially long-term. The objective of dispersant use is to transfer oil from the water surface into the water column. This decreases exposure to oil for organisms that dwell on the surface and the shoreline. But the effect doesn’t turn out to be good for organisms living underwater. Dispersants increase the exposure for the water column’s communities of fish, eggs, larvae, as well as shrimp, corals, oysters, and other aquatic creatures. When trying to minimize the damage coming to the shore, it can be more seriously damaging the marine ecosystem.       

            2. Toxicity

Because it is so incredibly toxic, the UK’s Marine Management Organization has completely banned Corexit 9500. In Crude Oil and Other Oil Dispersants, is being reported that 2.61 parts per million of Corexit 9500 (mixed with oil) is lethal to 50% of fish exposed to it within 96 hours.  That means that 1 gallon of Corexit 9500 and oil mixture is capable of rendering 383,141 gallons of water highly toxic to fish. When I asked Dr. Richard Snyder, a marine biology professor at UWF and environmentalist, if dispersants were dangerous to marine life, he replied, “Yes. Think dish detergent in your fish tank.”

             Decisions should be made regarding the impact to the ecosystem as a whole, and this often becomes a trade-off among different habitats and species. Ecological factors that go into this decision include: expected sensitivity of exposed resources, proportion of the resource that would be affected, and recovery rates. Comparing the possible ecological consequences and toxicological impacts of these trade-offs is difficult. Richard Snyder agrees, “There were not perfect solutions, only tradeoffs. Use of dispersants increased bacterial breakdown of the oil but also increased its immediate toxic effect.” 

Dispersants can also affect humans negatively.

B. Humans

            Chemical dispersants can concentrate the leftover oil toxins in the water. They are carcinogenic, mutagenic, and highly toxic. [pp: food chain] The use of chemical dispersants has been raising some troubling questions about threats of cascading up the food web. Plankton and fish larvae will be poisoned before making their way into the animals higher up the food chain. Humans and surface animals may not get much affected by the slick but they can be affected by consuming these aquatic animals that are poisoned.

            [pp: cleanup worker] Clean-up workers for oil spills are also caught by the impact of chemical dispersants. CNN once reported that cleanup workers for the Exxon-Valdez spill had a life expectancy of just 51 years. Corexit 9500, the newest widespread dispersant originally developed by Exxon, is associated with headaches, vomiting, and reproductive problems as side effects at high exposure to clean-up workers. If inhaled, the respiratory tract can be irritated. People may feel weak, slur speech, lose concentration and judgment, and experience blurred vision and dizziness. Prolonged fume exposures can affect liver, blood, microcytosis, urinary system, and cause lung hemorrhage and Bronchopneumonia. According to the EPA, people working with dispersants are strongly advised to use a half face filter mask or an air-supplied breathing apparatus to protect their noses, throats, and lungs, and they should wear rubber or PVC gloves, coveralls, boots, and chemical splash goggles to keep dispersants off skin and out of their eyes.


[pp: Pensacola beach] Dispersant use has always been full of uncertainties. Loads of research is currently being done to fully understand dispersant effects. Richard Snyder says that people will not see or feel dispersants in the water and that the water has been safe to swim in for quite some time. We should all be able to enjoy the beautiful beaches on the Gulf Coast. The fact the UK’s Marine Management Organization has banned Corexit from being used in British waters is very telling about the dangers of dispersants. While there are good aspects of dispersant usage, there are also many negative factors that people should know about.


Dearing, S. (2010, August 4). U.S. scientists question use of dispersants on gulf oil spill. Retrieved from

Goodell, J. (2010, August 5). The poisoning. Rolling Stone, 1110, 59-65.

The International Tankers Pollution Federation Limited. (2010). Spill Response: Dispersants. Retrieved from

Ocean Studies Board. (2005). Oil spill dispersants: efficacy and effects. Retrieved from

Reinhardt, D. (2010, June 10). Crude oil and other oil dispersants: chemistry and facts. Retrieved from

Snyder, R. Personal communication. February 23, 2011.

The United States Environmental Protection Agency.( 2011, January 10). Questions and Answers on Dispersants. Retrieved from