An environmental impact statement (EIS), under United States environmental law, is a document required by the 1969 National Environmental Policy Act (NEPA) for certain actions "significantly affecting the quality of the human environment".[1] An EIS is a tool for decision making. It describes the positive and negative environmental effects of a proposed action, and it usually also lists one or more alternative actions that may be chosen instead of the action described in the EIS. One of the primary authors of the act is Lynton K. Caldwell.
Preliminary versions of these documents are officially known as a draft environmental impact statement (DEIS)[2] or draft environmental impact report (DEIR).[3]