Army Secretary Clifford L. Alexander Jr., brushing aside vehement objections from high-ranking environmental officials, yesterday approved a controversial permit for building a much-delayed oil refinery in southeastern Virginia.

The more than $600 million refinery -- the first scheduled to be built on the East Coast since 1957 -- had been strongly opposed by the Interior Department, Environmental Portection Agency and numerous environmental groups. Interior Secretary Cecil D. Andrus yesterday expressed disappointment and disagreement with Alexander's decision.

The refinery -- designed to handle 175,000 barrels of curde oil daily and located in Portsmouth -- had been viewed by industry officials, however, as a symbol of environmental roadblocks confronting American energy producers. Alexander's announcement was hailed as a breakthrough by Portsmouth Major Richard J. Davis, Virginia Gov. John N. Dalton and officials of the Washington-based firm that wants to build the refinery, the Hampton Roads Energy Co.

"We waited five years for this permit -- this has been the longest, toughest one," said company vice prsident Robert E. Porterfield.

Alexander said he sought to balance the nation's energy needs against the environmental objections. "I believe that the refinery and the Chesapeake Bay resources can coexist free of disastrous implications," he said. Alexander had tentatively approved the refinery in October, but had delayed a final decision to allow Andrus to register his objections.

An Army permit was required because the refinery's construction and operation would affect navigable waters. Alexander said he had instructed the Army Corps of Engineers to issue the permit to build the refinery and its marine terminal, which are planned for a 623-acre site on the west bank of the Elizabeth River, a tributary of Hampton Roads, the harbor connecting the James River, bay and Atlantic.

The battle over the refinery has centered largely on contentions by enviromentalists that the refinery's construction would likely lead to oil spills and damage to oysters, crabs and other marine life in the Chesapeake Bay area.

Despite Alexander's "final decision" yesterday, several other obstacles still confront the Hampton Roads Energy Co. For these and other reasons, Poterfield declined yesterday to say how soon the refinery's construction might start.

Refinery opponents have threatened a lawsuit to block the project and EPA has yet to approve two necessary permits dealing with air pollution.

One would govern emissions of three pollutants -- sulfur dioxide, nitrogen oxides and particulate matter -- from the plant. The other involves a proposal for alleviating discharges of hydrocarbons. The Virginia government has proposed to shift from oil-based to water-based asphalt in road construction in an attempt to offset increased hydrocarbon emissions from the refinery.

EPA and company officials indicated that decisions on the two permits were likely within the next few months.

The proposed refinery, moreover, faces prospects of court challenges by environmental organizations. "This is a black day," Joanne Berkley, vice chairman of Citizens Against the Refinery's Effects (CARE), said yesterday, noting that her group's board of directors already voted to contest Alexander's decision.

The National Wildlife Federation and other national environmental groups are preparing to join the anticipated court battle over the refinery, despite what are viewed as substantial legal obstacles.

"There's no question that it's a very difficult case," said Pat Parenteau, counsel to the National Wildlife Federation. "It would not be brought if it (the Chesapeake Bay) were not the largest and most productive estuary in the country."

Alexander's long-awaited decision had, nevertheless, been widely viewed as the key to the refinery's fate. Dalton had cited the proposed refinery as "a prime example of the costly delays and policy frustrations caused by overregulation of energy development."

The Hampton Roads Energy Co. is owned by oil entrepreneur John K. Evans of Washington and by Cox Enterprises, Inc., an Atlanta based newspaper publishing firm.