Here is an observer's view of a dispersed oil slick at West Cameron Block 1988, Gulf of Mexico. This photo is an example of a case in which, just using visual observation, it is possible to see that application of dispersant to an oil slick has caused successful dispersion: what had been a cohesive slick has broken up into streaks, and oil that has been dispersed into the water column appears as a light-colored plume around the remaining streaks of surface oil.
Visual observation, however, is not always sufficient to determine whether or not dispersants are effective.
Revised: July 17, 2001
Office of Response and Restoration, National Ocean Service, National Oceanic
and Atmospheric Administration