Conventional Dispersants

Conventional dispersants, also known as second-generation or Type 1 dispersants, are mixtures of surfactants and one or more solvents. They are specifically formulated to break up oil slicks into tiny droplets that disperse into the water column, preventing the oil from reaching shorelines. These dispersants are applied undiluted (neat) from vessels and use non-aromatic hydrocarbons as their solvent. The recommended dosage for conventional dispersants is 30–100% of the oil's volume.

Concentrate Dispersants

Concentrate dispersants are a more modern form, categorized as third-generation or Type 2 and Type 3. Like conventional dispersants, they're used to break up oil slicks. However, their application and composition differ slightly.

• Type 2 concentrate dispersants are applied diluted from vessels. They use oxygenates as their solvent, and the dosage is typically 5–15%.
• Type 3 concentrate dispersants are applied undiluted from either vessels. Their solvent is non-aromatic hydrocarbons, and their dosage is also 5–15%.

General Uses and Considerations

Dispersants work by enhancing the natural process of oil dispersion caused by water agitation. Their primary purpose is to reduce the amount of oil coming ashore by converting floating oil into small droplets that are less likely to contaminate shorelines and wildlife.

Advantages of using dispersants include:

• Their ability to be used in stronger currents and rougher seas.
• They are the quickest response method for oil spills.
• They help to inhibit the formation of water-oil emulsions, which can make oil more difficult to clean up.
• They reduce the possibility of contamination for sea birds and mammals that would otherwise encounter the surface slick.

Disadvantages of using dispersants include:

• They can adversely affect some marine organisms that would not typically be reached by the oil on the surface.
• They are not effective on all types of oils or in all environmental conditions.
• If used too close to shore, they can increase the penetration of oil into sediments.
• There is a limited time window after a spill during which they can be used effectively.