The EIS need not "consider an alternative whose effect cannot be reasonably ascertained, and whose implementation is deemed remote and speculative."

"Judicial review of the range of alternatives considered by an agency is governed by a `rule of reason'that requires an agency to set forth only those alternatives necessary to permit a `reasoned choice.'"

"There is reason for concluding that NEPA was not meant to require detailed discussion of the environmental effects of `alternatives' put forward in comments when these effects cannot be readily ascertained and the alternatives are deemed only remote and speculative possibilities, in view of basic changes required in statutes and policies of other agencies—making …

The court's responsibility lies in assuring that the agency had before it all the data to make an informed decision that adequately took account of the important environmental concerns.

Disagreement among experts, however, as to the technical plans and engineering feasibility of proposed action will not invalidate a FES.

Supporting studies need not be physically attached to the EIS; they need only be available and accessible.

Thus, for example, agencies are not required to consider alternatives which are "remote and speculative,"

Time and resources are simply too limited to hold that an impact statement fails because the agency failed to ferret out every possible alternative, regardless of how uncommon or unknown that alternative may have been at the time the project was approved.

—delegation of the EIS preparation to a private consult-ing firm with a "financial interest in an affirmative decision on the proposed project" was found to be acceptable under NEPA.