While domestic oil production can help reduce America's dependency on foreign oil, it also brings a host of environmental risks. Extraction techniques can cause geologic instability and taint the water table, and offshore drilling accidents sometimes result in regional disasters that can destroy entire ecosystems.
The boom in domestic oil production came about as a result of increasing oil prices during the beginning of the 21st century. America has a number of oil reserves, but much of that oil is trapped in shale or other formations that are more difficult and expensive to extract than traditional oil fields. In particular, the formations found in North Dakota have been heavily exploited, causing a local economic boon in the formerly sparse region of the country.
The techniques required to extract this oil effectively, however, can cause problems for the local environment. Fracking, the practice of injecting fluids into a formation to increase the pressure and pull out more oil, has been linked to pollution and an increased chance of earthquakes. Transporting extracted oil has its own dangers, including the potential of rail or pipeline accidents. The Deepwater Horizon accident in 2010 resulted in the largest offshore oil spill in history. The spill contaminated the Gulf of Mexico, devastating the wildlife in the region, and it resulted in enormous economic damage.