NOAA’s National Ocean Service • Office of Response and Restoration

Tarballs

W hat are tarballs, and how 

do they form?

Tarballs, the little, dark-colored 

pieces of oil that stick to our 

feet when we go to the beach, 

are actually remnants of oil 

spills. When crude oil (or a 

heavier refined product) floats on the ocean surface, its physical 

characteristics change. During the first few hours of a spill, the 

oil spreads into a thin slick. Winds and waves tear the slick into 

smaller patches that are scattered over a much wider area. 

Various physical, chemical, and biological processes change 

the appearance of the oil. These processes are generally called 

“weathering.”

Initially, the lighter components of the oil evaporate much like a 

small gasoline spill. In the cases of heavier types of oil, such as 

crude oil or home heating oil, much of the oil remains behind. 

At the same time, some crude oils mix with water to form an 

emulsion that often looks like chocolate pudding. This emulsion is 

much thicker and stickier than the original oil. Winds and waves 

continue to stretch and tear the oil patches into smaller pieces, or 

tarballs. While some tarballs may be as large as pancakes, most 

are coin-sized (a relatively large tarball is shown in the photo at 

left). Tarballs are very persistent in the marine environment and 

can travel hundreds of miles.

How long will tarballs remain sticky?

Weathering processes eventually create a tarball that is hard 

and crusty on the outside and soft and gooey on the inside, not 

unlike a toasted marshmallow. Turbulence in the water or beach 

activity from people or animals may break open tarballs, exposing 

their softer, more fluid centers. Scientists have not been very 

successful at creating weathered tarballs in the laboratory and 

measuring the thickness of the crusty outer layer. Therefore, we 

don’t know how much energy is needed to rupture a tarball.

We do know that temperature has an important effect on the 

stickiness of tarballs. As air and water temperatures increase, 

tarballs become more fluid and, therefore, sticky--similar to 

an asphalt road warmed by the summer sun. Another factor 

influencing stickiness is the amount of particulates and sediments 

present in the water or on the shoreline, which can adhere to 

tarballs. The more sand and debris attached to a tarball, the 

more difficult it is to break the tarball open. These factors make it 

extremely difficult to predict how long a tarball will remain sticky.

Are tarballs hazardous to your health?

For most people, an occasional brief contact with a small amount 

of oil, while not recommended, will do no harm. However, some 

people are especially sensitive to chemicals, including the 

hydrocarbons found in crude oil and petroleum products. They 

may have an allergic reaction or develop rashes even from brief 

contact with oil. In general, we recommend that contact with oil 

be avoided. If contact occurs, wash the area with soap and water, 

baby oil, or a widely used, safe cleaning compound such as the 

cleaning paste sold at auto parts stores. Avoid using solvents, 

gasoline, kerosene, diesel fuel, or similar products on the skin. 

These products, when applied to skin, present a greater health 

hazard than the smeared tarball itself.

Tarballs bits and pieces

Beach Cleanup

There is no magic trick to making tarballs disappear. Once 

tarballs hit the beaches, they may be picked up by hand or by 

beach-cleaning machinery. If the impact is severe, the top layer of 

sand containing the tarballs may be removed and replaced with 

clean sand.

Are there more tarballs on beaches along the East Coast than 

on the West Coast?

The number of tarballs found on the beach depends on several 

factors: tanker traffic, wind patterns, sea currents, whether an 

oil spill occurred recently, and how often the beach is cleaned. 

Obviously, some beaches may have more tarballs than others, but 

to our knowledge, East Coast beaches are not necessarily more 

polluted with tarballs than beaches along the West Coast of the 

United States.

Reporting

New tarballs appearing on a beach may indicate an oil spill. If you 

notice unusual numbers of tarballs on the beaches, call the U. S. 

Coast Guard any time at (800) 424-8802.
U.S. Department of Commerce • National Oceanic and Atmospheric Administration November 2006

NOAA’s Office of Response & Restoration—Protecting our Coastal Environment

For further information about NOAA’s Office of Response and Restoration, 

please visit our Web site at 

http://response.restoration.noaa.gov or call (301) 713-2989.

References

Agency for Toxic Substances and Disease Registry. 1999. 

Toxicological Profile for Total Petroleum Hydrocarbons (TPH). Atlanta: 

U.S. Department of Health and Human Services. 231 pp.

Fingas, M.F., W.S. Duval, and G. B. Stevenson. 1979. The Basics 

of Oil Spill Cleanup. Hull, Quebec, Canada: Minister of Supply and 

Services. 155 pp.

Payne, J.R., and C.R. Philips. 1985. Petroleum Spills in the Marine 

Environment: Chemistry and Formation of Water-in-Oil Emulsions and 

Tar Balls. Chelsea, MI: Lewis Publishers. 148 pp. 

For additional information: 

http://response.restoration.noaa.gov

orr.adios@noaa.gov

(206) 526-6317