Government agencies, landowners, lenders, and investors to name a few interested parties increasingly scrutinize companies drilling for and producing oil and natural gas to evaluate their potential impact on the environment and the resulting liabilities. Concerns range from how a planned drilling operation will affect wetlands and aquatic ecosystems to the potential economic effect on an investment in a producing field from governmental or private lawsuits. In this paper, I will discuss the potential environmental obstacles and liabilities that may be presented to oil and gas companies now and in the future as their activities continue to present environmental risks. I will discuss four general categories: (1) environmental permits, licenses, or other governmental authorizations necessary to begin or continue operations, (2) civil and criminal sanctions incurred for failure to comply with environmental statutes and regulations, (3) remedial obligations imposed by environmental laws, and (4) lawsuits by landowners and others claiming property damage or personal injury due to alleged environmental contamination. Many oil and gas companies are not only assessing the effect of environmental legal liabilities on their business but also developing some form of environmental management system to address these risks.