PRUDHOE BAY, ALASKA, JUNE 19 -- This sprawling Arctic oil field celebrated its 10th anniversary today -- a steel and gravel monument to the quest for American oil independence that faces another major battle on another flat, marshy plain just 60 miles away.

Ten years after the 138-degree petroleum from beneath the frigid Alaska north slope first headed south through the Trans Alaska Pipeline, few of the many predicted disasters have occurred. There have been no major spills. The permafrost -- permanently frozen subsoil -- remains intact. The caribou who come through here or traverse the pipeline are enjoying a population boom.

Prudhoe Bay has become the largest oil field in American history and with nearby wells is producing today one-fifth of all U.S. petroleum. Yet, with the nation's most promising new areas for oil exploration just to the east and with American oil imports again climbing, the experts who brought this off find themselves blocked by some of the same environmentalist forces that fought the pipeline.

"The oil we will need to carry us into the 21st century," said Standard Alaska Production Co. President George N. Nelson, is "being held hostage" in the battle over the Arctic National Wildlife Refuge, a 19-million-acre tract down the coast.

Environmentalists charge that caribou in that refuge will be unable to adjust to drilling, particularly in their calving grounds and the ice flows where they escape summer mosquitos. They say the growth of the caribou population in the pipeline area only proves the natural disruption oil brings, for it has come at the expense of wolves and grizzly bears killed or frightened away by the influx of humans.

Prudhoe Bay, now pumping about 2 million barrels of oil a day down the pipeline to Valdez at the speed of a brisk jog, is expected to become a busy way station this August for legions of federal visitors flying on fact-finding missions to the refuge. This summer also marks the beginning of vacation bus tours to Prudhoe Bay up the 416-mile Dalton Highway, which until now carried only truckers supplying the pipeline.

Roger Herrera, the British-born Standard geologist who first explored the the refuge 20 years ago, expects to help escort members of Congress over the refuge's polygonally patterned tundra and meandering rivers. Fourteen separate groups, including two House and one Senate committee, are expected, as low oil prices mask growing worries among energy experts about dwindling U.S. resources.

Randall Snodgrass, Alaska program director for the Wilderness Society in Washington, also will be coming. For him and many other environmentalists, the refuge is "the last intact ecosystem in the country." Not only will oil development destroy it, he said, but it is unnecessary. He said improving the gasoline efficiency of U.S. automobiles just one mile a gallon eventually would save as much oil, about 3 billion barrels, as the middle range of estimates say the refuge might provide.

Leaders of the Anglo-American petroleum industry gathered here under the 24-hour sun today to celebrate the 10th anniversary of the first surge of oil down the pipeline and express consternation at the failure to follow up their success quickly.

Standard Oil President Frank E. Mosier predicted success at the refuge "if sanity prevails and we are able to show what professional environmentalists can do -- and by that I mean oil men."

Other U.S. exploration sites still hold promise -- the deeper Gulf of Mexico, the California coast, Bristol Bay -- but none has all that is offered by the refuge's coastal plain. Hererra, now Standard Alaska's manager of exploration and lands, notes that seismic studies show large geologic structures that often act as traps for oil and gas. The oil already found here is an additional clue.

Chevron and British Petroleum, which now owns Standard, have sunk a test well in the small piece of the refuge controlled by an Alaska native corporation, but they are keeping the results secret. More extensive exploratory wells cannot be drilled unless Congress approves, and one bill submitted by House Interior and Insular Affairs Committee Chairman Morris K. Udall (D-Ariz.) would ban drilling.

In 1986, the United States consumed about 16 million barrels of oil a day while producing 8.9 million barrels a day from its own wells. Historically, the country has drawn about two-thirds of its domestic oil from fields representing only 3 percent of all domestic oil fields discovered, according to a Congressional Research Service study. Those large fields are becoming scarce, with the refuge site thought to be one of the few left.

The principal oil companies at Prudhoe, Standard and ARCO invited several journalists here to watch the anniversary celebration and hear their message on the need for the refuge. The tour included a bumpy flight over its vast expanse, a patchwork of brown tundra, gray snow and blue water.

There was also a message here at milepost 0, where the pipeline rises out off the earth like the snout of a giant mosquito and heads south. Despite a loud, steady rumble from the main pumping station 200 yards away, two caribou strolled under the pipeline -- here suspended six feet off the ground -- and headed west.

The Central Arctic and Nelchina herds of caribou that encounter Prudhoe Bay and the pipeline have grown, environmentalists concede, but that does not mean that the Porcupine caribou herd at the refuge will be as fortunate. These caribou seem to choose a different part of the refuge every year, usually a flat barren spot (so they can spot wolves) where the snow has melted (so their brown calves will be camouflaged.)

But oil company environmentalists argue that there are more than enough calving sites and, sometimes, like this year, the caribou calve in Canada. They say the exploratory drilling -- all that is asked for now since the presence of oil must be proved -- is done in winter, when the herds are far to the southeast.

Demands to protect the coastal plain may evoke an image "something along the lines of Yosemite," said Dan B. Huxley, development planning manager for Standard Alaska. "In reality, the place is an arctic desert covered with ice and snow and largely uninhabitable nine months of the year."

Snodgrass rejects such talk. Even in winter the area is alive with arctic foxes, polar bears and other creatures. He called the refuge "the Yellowstone Park of the 21st century." Those who say it is too remote to worry about, he added, should remember that some Montana politicians made the same argument about Yellowstone in 1872.