US HB6163

Amends Section 108 of the National Environmental Policy Act of 1969 (42 U.S.C. 4336b) to allow federal agencies to reuse previously completed environmental assessments and environmental impact statements for new projects

Permits a lead agency to satisfy NEPA requirements for a new major federal action by relying on existing environmental documents if the new action and its effects are "substantially the same" as those previously analyzed

Allows agencies to use environmental documents completed by other federal agencies or by project sponsors under federal supervision, not just their own prior work

Authorizes lead agencies to modify previously completed environmental assessments or impact statements when a new action is not substantially the same, rather than starting from scratch

Requires any modified environmental document to be made publicly available as a new environmental assessment or environmental impact statement