Investigators Question Navy Probe of Iowa Blast : Battleships: One inquiry points to a possible accidental cause of the gun explosion. The GAO also has doubts about the sabotage theory.

Investigators from a national laboratory, in another blow to the Navy’s conclusions about the battleship Iowa disaster, told Congress on Friday that “a very simple scenario” could have accounted for the gun turret blast that killed 47 sailors last year.

Bags of gunpowder could have exploded after being pressed too hard and fast by a rammer device into the 16-inch gun’s barrel, Sandia National Laboratory officials said in testimony before the Senate Armed Services Committee.

In separate testimony, the General Accounting Office also called the Navy’s finding of probable sabotage into question and told the Senate panel that the nation’s four World War II-vintage battleships “seem to be top candidates for deactivation.”

The alternative explanations were aired only a day after Navy engineers produced an “unintended ignition” during tests of gunpowder bags like those used in the Iowa, another indication that the fatal explosion could have been accidental.

In its investigation report issued last September, the Navy concluded that the gunpowder could not have ignited accidentally.

After finding traces of a “foreign material” inside the breech of the gun, the Navy concluded that a sailor, 24-year-old Gunner’s Mate Clayton M. Hartwig, “most probably” placed a detonator inside the gunpowder bags and set off the blast intentionally.

Hartwig and 46 others perished in the blast, which occurred April 19, 1989.

Officials from Sandia, one of three major research institutions operating under the Energy Department, challenged the Navy’s claim that chemical traces discovered in the gun barrel pointed unequivocally to the presence of an unauthorized detonator inside the powder charge.

Most of the chemicals the Navy cited as probable components of a homemade detonator were commonly used in regular cleaning and maintenance of the gun barrel or were used to clean the turret after the explosion, the Sandia officials said.

In addition, the investigators offered evidence that the 600 pounds of gunpowder may have been rammed into the breech of the 16-inch gun so rapidly and pushed so far beyond its normal position that several explosive pellets could have sent sparks into an adjacent black powder ignition pad. The pad, in turn, would have ignited the rest of the bags of the explosive.

The theory, which the Navy first dismissed as irrelevant, offers an important alternative explanation of the cause of the disaster, one that casts serious doubt on the Navy’s controversial suggestion that Hartwig sabotaged the gun.

“We believe this is an extremely important result,” said Richard L. Schwoebel, chairman of the Sandia Advisory Group, which was created to look into the Navy’s investigation of the Iowa blast. “It suggests another way, a very simple scenario, in which the explosion could have occurred.”

The laboratory’s findings were underscored by a separate review undertaken by the General Accounting Office, the investigative arm of Congress.

“A close evaluation of the way the Navy conducted its investigation indicates that too early in the investigation (the Navy) ruled out other possible or plausible causes of the explosion,” said Frank C. Conahan, GAO assistant comptroller.

Citing unanswered safety questions and the cost of operating the nation’s four World War II-vintage battleships, Conahan told lawmakers that the recommissioned vessels “seem to be top candidates for deactivation” during the Pentagon’s coming budget crunch.

The GAO also reported that training, manpower and organizational problems that could affect safety continue to be a problem aboard the Iowa and the other three battleships.

In its investigation of last year’s blast, the Navy found a large number of inadequacies in the Iowa’s manpower and training procedures, but it said that none of the shortcomings contributed to the blast.

Conahan told the committee that the battleships are manned by personnel that tend to be less qualified, more poorly trained and less likely to get promotions than Navy personnel aboard other ships.

The Senate hearing produced harsh criticism of the Navy from Hartwig’s family and from lawmakers.

“The technical part (of the Navy’s investigation) is in shambles,” said Hartwig’s sister, Kathleen Kubicina, who has fought a pitched battle against the Navy’s findings. “Because there is doubt now, that’s great. That’s a victory for us.

“This was just a big horrible miscarriage of justice, she added.

Several lawmakers faulted the Navy’s investigation for discounting the possibility of accidental ignition and focusing with increasing intensity on Hartwig.

“The Navy’s investigative effort was flawed,” said Sen. Sam Nunn (D-Ga.), chairman of the Armed Services Committee. Nunn faulted the service for conducting an informal inquiry led by a single officer rather than a hearing procedure in which Hartwig’s family and other parties could have retained legal counsel, presented formal evidence and cross-examined witnesses.

Nunn said the Navy should review its guidelines for such accident investigations, “particularly when an individual who is deceased is pointed to as a party” to an accident.

The Navy placed a moratorium on the firing of the 16-inch guns after Thursday’s “unintended ignition” during testing at the Navy’s Surface Weapons Center at Dahlgren, Va. The four battleships, meanwhile, were in port in Long Beach and in Norfolk, Va.