Environmental impact statements must be prepared by federal government agencies early in the budget-proposal stage whenever the agencies take a long-range "new look" at an existing government program that affects the environment, the U.S. Court of Appeals ruled here yesterday.

The ruling reversed a specific finding by a lower-court federal judge that had required a government agency to prepare an environmental impact statement with each annual budget request in one such case, but still expanded the application of environmental laws early in the budgetary process.

To require environmental impact statements each year on continuing programs would be "ridiculous," the court said yesterday. But, the ruling continued, the federal government had an obligation early in the budget process to consider environmental issues to some extend.

The ruling came in a case brought by environmentalist groups, including the Sierra Club, against the secretary of the interior and the Office of Management and Budget.

The environmentalists claimed that an environmental impact statement was needed by Interior's Fish and Wildlife Service in its attempts to decrease the budget and cut down operations for the National Wildlife Refuge System.

In the U.S. District Court, the judge found that the environmental impact statement was needed in connection with the wildlife service's budget requests and that the Office of Management and Budget must prepare guidelines requiring such statements early in the budgetary process.

The government appealed, saying the proposal of a budget to OMB by the wildlife service was only an "intermediate step" in the budget process and that stage was too early to require the sometimes lengthy environmental impact statements.

U.S. Circuit Judge Harold H. Leventhal, writing for himself and U.S. Circuit Judge David L. Bazelon, said "it would be absurd to require an EIS on every decision on the management of federal land."

However, the majority judges said national environmental laws should be applied in proposals to OMB when an agency's request for budget approval and appropriations "is one that ushers in a considered programmatic course following a programmatic review."

In other words, the judges said, such a statement is required when "a new look is had" at a federal program and the result is what amounts to a proposal for legislation.

The majority judges upheld the requirement that OMB prepare internal guidelines for environmental impact statements to be used when it considers budget changes that amount to a "new look" at an ongoing program.

U.S. Circuit Judge George MacKinnon dissented from the majority opinion, saying he felt national environmental laws were never intended to apply to the budgetary process. He said such budget requests do not amount to "proposals for legislation."

"I do not feel that an EIS is ever required at the clearly pre-decisional stage at which the OMB or an agency submits a mere appropriation request," MacKinnon said.