The flaming 1,000-foot hulk of the tanker Atlantic Empress apparently exploded off this tiny calypso island today, spewing millions of gallons of oil in the aftermath of the long-prophesied disastrous collision of the supertanker age.

While Coast Guard boats and planes from nearby Trinidad searched the oil-stained waters for 35 missing crewmen, a seagoing tug fought strong easterly winds and currents to pull the Aegean Captain, the second supertanker, clear of what threatens to become the largest oil spill in history.

The Atlantic Empress and the Aegean Captain collided in heavy rain at dusk Thursday, 20 miles northeast of Tobago and about 100 miles off the Venezuelan coast in the area where the Atlantic and Caribbean meet.

Both ships were fully loaded at the time. Each carried the potential thermal energy of a two-megaton hydrogen bomb.

Seven men from the Atlantic Empress and all 35 crewmen from the Aegean Captain were rescued. All were hospitalized here for burns, but by sunset a police spokesman said all had been released from the hospital.

A spokesman for the police superintendent of Trinidad and Tobago said the Atlantic Empress exploded about 4:30 p.m. and sank. Other reports, however, indicated that the ship or part of it still was visible at sunset.

By late this afternoon, the two burning ships had bled a vast black slick of crude oil across the usually crystalline Caribbean.

The spill stretched for more than 35 miles, just missing the fine and beaches at the island's northern tip and leaving hundreds of sea birds flopping helplessly, their feathers saturated with oil.

No one can say precisely how much oil has been spilled. Together, however, the two tankers carried 3.5 million barrels of oil - an amount equal to one-fifth of the daily petroleum consumption of the United States.

At least 2 million barrels of that appear almost certain to go into the water during the coming weeks, although some of the cargo of the Aegean Captain may be saved.

Firemen boarded the abandoned vessel and, according to one report, had brought under control flames that were leaping from a gash in the starboard bow.

Lt. Geoffrey L. Abbott of the Coast Guard Rescue and Coordination Center in San Juan, Puerto Rico, said the Atlantic Empress was carrying about 1.89 million barrels of crude oil at the time of the accident.

A spokesman for the owners of the Aegean Captain in London said the vessel was bound for Singapore after having loaded oil from refineries at Aruba and Bonaire in the Netherlands Antilles, west of here.

Authorities here are still investigating the cause of the collision. The ships struck each other at about 8 p.m., during a rainstorm, in weather that the U.S. Coast Guard spokesman described as "not at all unusual" in the shipping lanes of the Caribbean.

Such ships routinely carry dual radar systems that can spot oncoming vessles 10 miles away.

Supertanker critics, including British writer Noel Mostert, author of the 1974 book "Supership," for years have characterized mammoth tankers as seagoing environmental disasters sailing toward a place to happen.

Mostert's allegations of shortcomings in Very Large Crude Carriers - tankers of more than 200,00 tons - have been disputed by oil shippers but accepted by many environmentalists.

Writing about that class of vessles, and not specifically about the tankers involved in Thursday's collision, Mostert said they are oversized and undermanned, and operate within an alarmingly slim safety margin.

Mortest was particularly critical of the steering and propulsion systems. He noted that, unlike large warships and container ships, which can be maneuvered in emergencies by their multiple propellers alone, most VLCCs have only a single propeller and no backup control systems.

Since it take at least three miles and about 20 minutes to stop a VLCC traveling at 16 knots, emergency steering is particularly vital, he said.

The 288,000 ton Atlantic Empress, a Greek-registered vessel, measures 1,139 feet from bow to stern, more than twice the size of the Washington Monument, and is as tall as a nine-story building.

According to records of the Tanker Advisory Center in New York City, it is owned by Sun Enterprises Limited of Peraeus, which operates 34 other tankers. It was built in Denmark in 1974.

The 1,066-foot, 207,000 ton Aegean Captain was built in Japan in 1968 for Shell Oil Co., which sold it in 1977 to Quadrant Shipping Corp., a subsidiary of Coulouthros Ltd. of London, the 46-vessel fleet of Greek shipping tycoon Spiros Niarcos.

While not specifically referring to either the Atlantic Empress or the Aegean Captain, Mostert wrote in 1974: "At five years old, many supertankers are at the halfway point of their write-off lives; holding such ships together beyond the five-year point can be onerous, but doing so after 10 years could be nightmarish. . . . As the present generation of tankers degenerates, there will be an accelerating rate of . . . accidents" and disaster, he wrote, would be almost inevitable. CAPTION: Picture, Supertanker Atlantic Empress is towed out to sea amid billowing black smoke after collision near Tobago. AP; Map, no caption, By Richard Furno - the Washington Post