10 SAILORS KILLED IN STEAM BLAST

The steam blast that killed 10 sailors aboard the Norfolk-based USS Iwo Jima in the Persian Gulf Tuesday could have been caused by faulty maintenance or sailors neglecting proper procedure as they fired the boilers, said Navy sources familiar with the operation of steam plants.

Steam at temperatures up to 850 degrees was spewed through a leak in the lines that power the amphibious assault ship, killing six sailors instantly, the Navy said. Four others, suffering from burns and inhaled steam, died hours later aboard the hospital ship USNS Comfort, the Navy said.

The number of sailors killed indicated that the leak occurred along a main steam line leading either to the turbine that turns the propeller shaft or in the line that powers the generator, which sends electricity to the ship, said the sources, who spoke on condition of anonymity.

Mostly junior sailors – boiler technicians, firemen and machinist's mates – work in the spaces where those lines run, the sources said.

"A main steam line had to go for that many people to be killed," said one of the sources, a Norfolk-based surface force official. The surface force consists of ships, such as the Iwo Jima, that are not submarines or fixed-wing aircraft carriers.

The Iwo Jima, the first in its class of warships, carries Marines and helicopters to be used for amphibious landings.

Navy officials would not speculate about the cause of the incident, saying that an investigation is under way and that a number of things could have gone wrong.

"It's real tough to say what could have caused a leak like that," said one of the sources, an assistant engineer for the Military Sealift Command. "But coming out of a routine maintenance period, it seems more likely that it was somebody making a mistake."

The incident occurred about 8:15 a.m. local time, 12:15 EST, as the ship was getting under way after a port call in Manama, Bahrain, according to a Navy release. The ship had been undergoing repairs for the past five days, the Los Angeles Times reported.

The ship, which was deployed to the Persian Gulf on Sept. 16, carries about 1,700 Marines and a Navy crew of about 685. The nearly 30-year-old vessel was heading toward the coast of Oman for an amphibious assault exercise on a beachhead there, according to news reports.

The boilers were shut down, and the ship was towed back to Bahrain about three hours after the incident, the Navy said.

Navy officials in Norfolk and Washington said they didn't know what kind of maintenance had been done in Bahrain.

"We don't know if it's related or not," said Lt. Cate Mueller, a spokeswoman at Atlantic Fleet headquarters in Norfolk.

The Navy uses steam to power most of its large ships, such as the assault ships and aircraft carriers. Other methods of powering ships include diesel and gas turbine. Gas turbines are used in newer ships and are similar to jet engines. And on some steam-driven vessels nuclear reactors create the heat.

The two boilers aboard the 602-foot Iwo Jima contain water that is turned into steam, which in turn flows over turbine blades to power the ship's propellers and generator.

The sources said if the maintenance involved any work on the boilers or pipes leading from them, an improperly tightened flange or an incorrectly installed gasket may have broken loose under the steam's pressure. Steam flows through the Iwo Jima's lines from the boilers at 600 pounds per square inch.

Another possibility was that the sailors who started the boilers failed to clear the lines of water, left when steam condensed after the engines were shut down for maintenance, the sources also said.

According to Navy procedure, water normally is drained from the lines through a series of valves before the steam is forced through the pipes. When steam pressure builds in lines with water that has not been removed, "it's like the water is being shot out of a gun," the sealift command engineer said.

Sailors call this a "water hammer," a phenomenon that has been known to break the blades on a turbine, the engineer said. It could easily cause a rupture in a steam line, he said.

"When you’re dealing with 600 pounds of steam, a water hammer can do a lot of damage," he said.

The pressure combined with the high temperatures make steam pipes dangerous in this sort of situation, the engineer said.

"That's why when one breaks, people die," he said. "In addition to the burns, you can't breathe."

Details about the incident trickled into Norfolk. Six of the bodies were flown to the United States, the Los Angeles Times reported.

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