The U.S. Department of Energy (DOE) and the Interstate Oil and Gas Compact Commission (IOGCC) are sponsoring a joint study to examine the changes in State regulatory programs and waste management practices since the mid-1980s, focusing on 17 States that reflect the diversity of Lower-48 E&P operations. This paper documents the preliminary findings of that study, which is expected to be completed Spring 1993. In 1987, the U.S. Environmental Protection Agency (EPA) identified what it felt were gaps and areas of concern with State regulatory programs for the management of oil and gas exploration and production (E&P) wastes, although it found State programs to be generally adequate. Included in the paper is an overview of the concerns expressed by EPA in 1987, a review of the budgets and staffing commitments of these 17 States to oil and gas regulation over time, and a review of the specific regulatory modifications made by the States since the mid-1980s to improve waste management and environmental protection associated with oil and gas E&P operations. The evolution of the waste management practices used by oil and gas operators since the mid-1980s is also briefly discussed.