The MMS prepared this environmental impact statement (EIS) on Chevron's plan to drill 20 new wells within the Destin Dome (DD) 56 Unit, to produce up to 450 trillion cubic feet of natural gas per day, and to transport the gas through pipelines to processing plants in Alabama. Volume 1---Section 1 states the reasons for the proposed development of the DD 56 Unit and describes the plan and pipeline in detail. Section II describes the proposal, the alternatives, and the mitigation measures. Section III describes the physical, biological, and social resources within the DD 56 Unit and in areas from Pascadoula, Mississippi, to Cape San Blas, Florida, that might be affected if Chevron is allowed to go ahead with the plan. This descriptive background information gives the status of these reasons as they are now. Section IV analyzes the environmental effects that could be anticipated from Chevron's plan, and a separate analysis of possible and expected effects is done for the resources described in Section III. Section V discusses how the Draft EIS was developed and distributed. Section VI lists the references cited in the main text. Section VII lists the people who wrote and worked on the EIS. Section VIII is a glossary of terms used. Section IX (Appendices) contains technical information, including descriptions of the geology and physical oceanography of the DD 56 Unit.