Petroleum and its derivatives supply a significant part of the world's energy. Oil is used to produce electricity, to operate vehicles and for a number of other vital purposes. Unfortunately, exploiting the earth's petroleum resources can be difficult, and it has a serious environmental impact. As oil reserves decrease, the disadvantages of drilling for oil increase.

Inaccessibility

World oil consumption continues to increase, and once-full reserves are slowly becoming depleted. This means that oil companies must work to find new sources of oil. Sources of oil once considered too difficult to drill, such as the continental shelves, are now being targeted for possible oil rigs. Distant parts of the planet, such as the Antarctic and inaccessible areas currently used as parks and wildlife refuges have also been considered as existing oil supplies begin to run dry. Oil extraction is expected to become steadily more difficult.

Oil Spills

Oil extraction and transportation comes with a risk of oil spills. As oil companies begin to exploit more difficult resources, such as off-shore oil reserves, and transport oil longer distances, the chance of a spill increases. For instance, 2010's Deepwater Horizon oil spill stemmed from a problem on an off-shore oil rig. According to Santa Clara University, only 5 to 15 percent of any oil spill can be recovered, leaving a large amount of oil in the environment. This oil can kill plants and animals, disrupt local ecosystems and cause serious damage to local businesses and tourism. Spilled oil is also considered a health hazard for humans.

Environmental Contamination

Petroleum drilling can release not only oil into the environment, but an assortment of other dangerous substances, such as heavy metals. According to Santa Clara University, drilling fluid and drilling mud often contain cadmium, mercury, arsenic, lead, radioactive materials and other hazardous waste. If allowed to escape, this waste can have serious environmental effects.

Health and Safety Hazards

Workers on oil rigs, both on land and off-shore, are routinely exposed to health and safety hazards. For instance, rigs drilling for oil often encounter pockets of pressurized gas which create an event called a blowout. Blowouts can cause fires, create an explosion and scatter drilling waste a significant distance. The 2010 Deepwater Horizon spill began with an explosion on the drilling rig which killed 11 workers and injured several more.