What is crude oil?

Crude oil is a dark yellow-to-black oily liquid that is usually found in natural underground reservoirs. It was formed when the remains of animals and plants from millions of years ago were covered by layers of sand. Heat and pressure from these layers turned the remains into crude oil. This process is why crude oil is called a fossil fuel. Crude oil is extracted and used to make fuel and other petroleum products.

Crude oil is a mixture of a wide variety of constituents. It consists primarily of hydrocarbons, which are chemicals composed of hydrogen and carbon. Crude oil also contains hundreds of substances that include benzene, chromium, iron, mercury, nickel, nitrogen, oxygen, sulfur, toluene, and xylene. Total petroleum hydrocarbons is a term used to describe the several hundred chemical compounds that originally come from crude oil.

There are four types of crude oil:
Class A: Light, Volatile Oils: These oils are highly fluid and highly toxic to humans, and include jet fuel and gasoline.
Class B: Non-Sticky Oils: These oils are waxy and less toxic to humans, and include diesel fuel and light crude oil.
Class C: Heavy, Sticky Oils: These oils are brown or black and sticky or tarry, and include most crude oils. Their toxicity is low, but if spilled, their impacts on waterfowl and wildlife can be severe.
Class D: Non-Fluid Oils: These oils are non-toxic and include heavy crude oils. They are difficult to clean up, and if spilled, their impacts on waterfowl and wildlife can be severe.

Crude oil is refined to produce gasoline, diesel fuel, jet fuel, residential fuel oil, kerosene, liquefied petroleum gases such as propane and other sources of energy to produce heat or electric power. It is also used to make lubricants, waxes, ink, crayons, eyeglasses, tires, CDs and DVDs, ammonia, dishwashing liquid, and some health and personal care products. The United States is the third top crude oil-producing country, after Russia and Saudi Arabia.

You can be exposed to crude oil if you live near an oil refinery or if there is an oil spill or leak nearby. You can be exposed if you eat contaminated seafood. Most exposure to crude oil is through total petroleum hydrocarbons and crude oil byproducts such as gasoline, oil products, heating sources, or consumer products. Everyone is exposed to total petroleum hydrocarbons from many sources.

You may be exposed to crude oil from an oil spill through tarballs at a beach or shoreline. Winds and waves can tear patches of spilled oil into smaller pieces called tarballs. Tarballs are small pieces of oil that are remnants of oil spills and can stick to rocks, sand, or marine animals. Oil contaminants may stick to the fur of pets, who can transfer the contamination to people.

You can be exposed to crude oil if you work in an oil refinery, on an oil drilling rig, or on an offshore oil facility. Exposure at work can occur through contact with the skin, ingestion, or breathing crude oil liquid, drops, or fumes.

Exposure to crude oil may irritate the eyes, skin, and respiratory system. It may cause dizziness, rapid heart rate, headaches, confusion, and anemia. Prolonged skin contact with crude oil may cause skin reddening, edema, and burning of the skin.

When crude oil is burned, either accidentally or as a spill control measure, it emits chemicals that affect human health. These chemicals include carbon dioxide, carbon monoxide, lead, nitrogen oxides, particulate matter, polycyclic aromatic hydrocarbons, sulfur dioxide , and volatile organic compounds.

If you are exposed to burning crude oil, you may be exposed to high levels of particulate matter and may experience the health effects of particulate matter. Exposure to burning crude oil may harm the passages of the nose, airways, and lungs. It may cause shortness of breath, difficulty breathing, coughing, itching, red or watery eyes, and black mucous.

Handling tarballs may cause an allergic skin reaction or skin rashes.

If you think your health has been affected by exposure to crude oil, contact your health care professional.

For poisoning emergencies or questions about possible poisons, contact your local poison control center at 1-800-222-1222.

This description is based on the information found in the Web links listed with this topic.

Locations where Crude Oil may be found: more neighborhoods >>
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Last Updated: February 12, 2013