OIL AND GAS TRANSPORTATION Department of Transportation Is Taking Actions to Address Rail Safety, but Additional Actions Are Needed to Improve Pipeline Safety

Oil and natural gas are found in a variety of geologic formations distributed across the country, such as shale and tight sandstone.3 Shale plays—sets of discovered or undiscovered oil and natural gas accumulations or prospects that exhibit similar geological characteristics—are located within basins, which are large-scale geological depressions, often hundreds of miles across, that also may contain other oil and gas resources.