The oil spill in the Gulf of Mexico was the worst spill in U.S. history. It had major environmental and economic effects.

Oil spills have the potential to affect human health. The kind of oil spilled in the Gulf, light crude oil, can cause skin irritation. Swallowing small amounts (less than a coffee cup) causes upset stomach, vomiting, and diarrhea, but is unlikely to have long-lasting health effects.

Oil also can spread in the water, join with the water to form a thick substance that is like hair mousse, sink, or form into sticky tar balls. Tar balls can also irritate the skin.

Studies are underway of the health impacts of the Gulf oil spill.