GALVESTON, TEX., JUNE 13 -- Salvage crews examining cargo sections of the still-burning Mega Borg discovered that the damaged tanker has lost 3 million gallons of oil since it exploded late Friday night and that oil still is leaking slowly from the center tank holding another 3 million gallons, Coast Guard Capt. Tom Greene said today.

But so far, a major spill has been averted along the Texas coast because the majority of the lost oil burned in fierce blazes aboard and around the ship or evaporated while floating in the warm Gulf of Mexico.

Greene said scientists and cleanup crews at the spill scene 57 miles southeast of Galveston have estimated that only 12,000 to 20,000 gallons of oil remain in the water. The spill is spread in a thin sheen whose outermost edge has what he described as a mousse-like consistency and is about 30 miles from land.

Greene said no oil is expected to reach the shore intact, although tar balls might drift onto the coast between Galveston and Corpus Christi by this weekend.

While a cleanup force of eight skimmers and more than 40 other vessels tries to contain the spill in international waters, the Norwegian Maritime Directorate, in consultation with the Coast Guard, opened hearings this morning on the cause of the incident.

One of the first facts revealed at the hearing in a small room at the historic Tremont Hotel was that the initial explosion apparently occurred at 11:30 Friday night, rather than 1 a.m. Saturday, as the Coast Guard has reported all week. It was unclear from today's testimony whether the 90-minute discrepancy indicated a delay in reporting the incident.

The new time was reported by Capt. C.M. Mahidhara, who testified that he had been aboard the Mega Borg only one month when the explosion occurred and was not totally familiar with the vessel or crew. He said he happened to be radioing his office in Hong Kong when the incident began.

"I heard a sort of bump -- I can't say there was an explosion -- a vibration," he testified. The lights went out, he said, tiles fell from the ceiling of the radio room and the passageway filled with smoke. Mahidhara said he rushed to his cabin where his wife and two young children were huddling in fear. "Get out! Get out!" he shouted, and they all ran to reach a lower deck but were trapped by smoke and flames.

"I looked forward and saw bright flames coming from the pump room . . . the ventilators," Mahidhara said. "Flames were licking up right over the bridge." Eventually, the captain said, he could count heads and determined that 37 people were on deck and four missing. Two, Seaman B. Cortez and Chief Officer Tojo Sagar, were found dead. Of Sagar, the captain noted: "They said he was in pieces."

Mahidhara, a sea veteran of 17 years, including nearly four as a captain, said crew members could do little to fight the fire. They tried to use ship's carbon-dioxide tank, he said, but the pipe had ruptured.

"There was too much smoke; the prevailing wind was starboard to port, so we did not attempt to start the emergency-fire pumps," he said, adding that smoke also prevented the crew from trying to reach the two men who are missing and presumed dead and were in the pump room. "It was too dangerous" to go there, he said. "I would have lost more people."

The panel of inquiry, seeking cause of the explosion, asked the captain whether special work was being done in the pump room, where the blast occurred. He said that the room had received "normal, routine maintenance" a few weeks earlier and that there was "no specific problem with the pumps we were using."

Fire flashed briefly aboard the ship late this afternoon, but Coast Guard officials said it was controlled quickly. Firefighters had been using foam for the first time but stopped when the re-flash occurred. The recurrence also delayed salvage efforts to stop leaks in the center tank.

The cleanup effort is expected to take a new twist Thursday. Texas General Land Commissioner Garry Mauro, a proponent of bioremediation to fight a spill, has persuaded federal officials to test the procedure for the first time.

The concept involves using microorganisms to "eat" the oil in a process that reduces oil to an emulsion of fatty acids. When the microbes run out of oil to eat, they die. Mauro said about 100 pounds of the substance will be used the next few days.

Tests at the University of Texas Marine Science Center indicated that bioremediation eliminated 99 percent of oil within 24 hours while not spreading toxicity through the food chain. But the process has never been tested on a large scale.