The sister of the sailor the Navy said blew up a gun turret on the USS Iowa last year said yesterday that her brother has been "vindicated" by a congressional study showing the explosion that killed 47 people could have been accidental.

Kathleen Kubicina, who has defended her brother Clayton M. Hartwig since the Navy identified him as the prime suspect in the April 19, 1989 explosion, said she was "happy" at Thursday's report by the General Accounting Office, which led the Navy to reopen the official investigation into the disaster and suspend all firings of 16-inch guns on four battleships.

But Kubicina, in an interview, said she remains angry with the Navy for what she considers an inadequate investigation, and particularly with Rear Adm. Richard L. Milligan, who issued the Navy investigative report last September. "I'm holding Rear Adm. Milligan responsible," she said.

Kubicina said her life has been consumed the past 13 months with her investigation of the incident as she sought to exonerate her brother. He was described by the initial Navy investigative report as a "loner, a man of low self-esteem," who "most probably" committed suicide and mass murder because he wanted to die in the line of duty.

Kubicina said the GAO study, formally presented to the Senate Armed Services Committee yesterday, cast doubt on the technical underpinnings of the Navy's conclusion that sabotage of gunpowder was responsible for the explosion. The GAO study, based on tests at Sandia National Laboratories in New Mexico, blew so many holes in the sabotage theory that "you can walk elephants through them," she said.

A House Armed Services Committee report issued March 5 had already undermined seriously the validity of the the Navy's criminal investigation, Kubicina said. That House report accused the Navy of using evidence selectively and presenting "an unbalanced view of the facts."

Kubicina said she now wants two things from the Navy:

"I want Rear Adm. Milligan to remove my brother's name from the report and I want the Navy to say three little words {about the cause of the explosion}: 'We don't know.' That's it."

She said she did not want an apology from the Navy. "I probably wouldn't accept it. How can I accept an apology from the Navy after the way it has treated" the families of those killed in the explosion? she said.

"First the Navy took my brother, then the Navy took the last 13 months of my personal life," said Kubicina, who lives in Cleveland. "My husband had to check the morning paper to see where I was. My children watched me on television."

Hartwig's shipmate and friend, Kendall Truitt, like Hartwig a gunner's mate, said the reopening of the probe was "long overdue." His life received much scrutiny after it was revealed that he was the beneficiary of a Hartwig insurance policy.

Appearing on CBS television's "This Morning," Truitt said he was "bitter mostly toward the Naval Investigative Service. It's like they had their scripts ready and they just wanted to fill in the parts."

His wife, Carole, said the new developments mean "people are finally starting to believe what we've known all along, that Clay didn't have anything to do with it, that Ken and Clay weren't lovers, that he didn't kill himself and 46 others in a suicidal rage.

"And it means that now the Navy is finally going to have to face the music and say there might have been another cause. It could very well have been an accident and I think it's wonderful. It's about time."