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Sticky Black Gobs on the Beach: The Science of Tarballs

What are those sticky black gobs sometimes seen on beaches? Tarballs. Explore the science of these pollutants.

flat, black tar glob on sand.
Tarball found on Dauphin Island, Alabama. Credit NOAA.

Walking on the beach is one of life’s great pleasures. Walking on the beach and ending up with sticky black balls attached to your feet is not so pleasurable. Tarballs, those sticky black globs, are often leftover from an oil spill. When crude oil (or a heavier refined product) hits the ocean’s surface, it undergoes physical change. The change process is called “weathering.” As the wind and waves stretch and tear the oil patches into smaller pieces, tarballs are formed. Tarballs can be as flat and large as pancakes, or as small as a dime.

people walking on beach with tarballs
Extensive tarballs are visible in the foreground and surf zone in this image from the Gulf Islands National Seashore, Flor., shot on July 1, 2010. Credit NOAA.

How long do tarballs remain sticky? Are tarballs hazardous to your health? How are tarballs removed from affected beaches? Those and other questions, including how to report new sightings of tarballs, can be found on our Tarballs page.

Last updated Tuesday, November 8, 2022 1:46pm PST